An Overview of IEEE 802.16m Radio Access Technology Globecom 2010

Dr. Sassan Ahmadi
Principal Engineer and Chief Architect, 4G Wireless Systems

Intel Architecture Group
Wireless Technology Division
Intel Corporation

December 6, 2010

 Road to 4th Generation of Cellular Systems
 Mobile WiMAX Network Architecture
 IEEE 802.16m Protocol Structure and System Operation
 MAC Layer
 Physical Layer
 IEEE 802.16m Mixed-Mode (Legacy) Operation
 IEEE 802.16m Performance Evaluation
 References

 Note: For more detailed information on IEEE 802.16m standard see the following
book:
• Mobile WiMAX, A Systems Approach to Understanding IEEE 802.16m Radio
Access Technology, Sassan Ahmadi, Academic Press, November 2010

Sassan Ahmadi/IEEE GLOBECOM 2010/December 2010 2

2007 2010

Cellular (3GPP)
1G 2G 3G
LTE/LTE-Advanced
Analog TDMA WCDMA

Broadband Wireless IEEE IEEE IEEE 802.16m
(WiMAX) 802.16-2004 802.16-2009

Wireless LAN IEEE
IEEE 802.11a/b/g IEEE 802.11n
(Wi-Fi) 802.11ac/ad

OFDMA + MIMO New Spectrum
All-IP Core Network

Sassan Ahmadi/IEEE GLOBECOM 2010/December 2010

Mobility
New capabilities of Systems Beyond IMT-2000

High New
Mobile
Enhanced Access
4G
IMT-2000
IMT-2000 Next Generation
3G of mobile WiMAX .

Evolution
mobile WiMAX

New Nomadic / Local
Low Area Wireless Access

1 10 100 1000

Peak Useful Data Rate (Mbits/s)

ITU-R Recommendation M.1645 Vision for Systems beyond IMT-2000


 The key features of IMT-Advanced systems can be summarized as
follows:
• Enhanced cell and peak spectral efficiencies, and cell-edge user
throughput to support advanced services and applications
• Lower air-link access and signaling latencies to support delay sensitive
applications
• Support of higher user mobility while maintaining session connectivity
• Efficient utilization of spectrum
• Inter-technology interoperability, allowing worldwide roaming capability
• Enhanced air-interface-agnostic applications and services
• Lower system complexity and implementation cost
• Convergence of fixed and mobile networks
• Capability of interworking and coexistence with other radio access
systems


50
Background
Services
BER < 10-6

10
Data Rate (Mbps)

Streaming Services
10-9 < BER < 10-6

5

Interactive Services
1 10-9 < BER < 10-6

0.5
Conversational
Services
10-6 < BER < 10-3

10 100 1000
Delay (ms)

Four service classes specified for IMT-Advanced systems (conversational, interactive,
streaming, background services) and their characteristics in terms of reliability, bit rate,
and latency


High Mobility New Mobile Access
(120 – 500 km/h)

IMT-Advanced
Enhanced Systems
IMT 2000 ,
cy
Systems a ten s
IMT 2000 g L i ce
Systems a sin erv
re S
ec ing
s , D reas
ate , Inc
ta R ility
Da ob New Nomadic/Local
Low Mobility/
s ing ng M
Nomadic rea rovi Wireless Access
(0 – 30 km/h) Inc Imp

1 10 100 1000

Layer 2 Data Rate (Throughput at MAC Layer) Mbps

The services and performance of the systems noticeably increased as the
systems evolve from one generation to another.


Requirements IMT-Advanced IEEE 802.16m
Peak spectrum efficiency DL: 15 (44) DL: 8.0/15.0 (22/44)
(bit/sec/Hz) (system-level) UL: 6.75 (24) UL: 2.8/6.75 (1x2/2x4)
DL: (4x2) = 2.2 DL: (2x2) = 2.6
Cell spectral efficiency
UL: (2x4) = 1.4 UL: (1x2) = 1.3
(bit/sec/Hz/sector) (system-level)
(Base coverage urban) (Mixed Mobility)
DL: (4x2) = 0.06 DL: (2x2) = 0.09
Cell-edge user spectral efficiency (bit/sec/Hz)
UL: (2x4) = 0.03 UL: (1x2) = 0.05
(system-level)
(Base coverage urban) (Mixed Mobility)
Latency (ms) C-plane: 100/U-plane: 10 C-plane: 100(idle to active); U-plane: 10
Optimal performance up to 10 km/h; Graceful: degradation up to
Mobility 0.55 at 120 km/h
120 km/h; Connectivity up to 350 km/h; Up to 500 km/h
bit/sec/Hz (link-level) 0.25 at 350 km/h
depending on operating frequency
Intra frequency: 27.5
Intra frequency: 27.5; Inter frequency: 40 (in a band); 60
Handover interruption time (ms) Inter frequency: 40 (in a band)
(between bands)
60 (between bands)
VoIP capacity 40 (4x2 and 2x4)
60 (DL: 2x2 and UL: 1x2)
(Active users/sector/MHz) (system-level) (Base coverage urban)
DL: 2x2 (baseline), 2x4, 4x2, 4x4, 8x8
Antenna Configuration Not specified
UL: 1x2 (baseline), 1x4, 2x4, 4x4
Cell Range and Coverage Not specified Up to 100 km; Optimal performance up to 5 km
Multicast and Broadcast Service (MBS) 4 bit/sec/Hz for ISD 0.5 km
Not specified
(system-level) 2 bit/sec/Hz for ISD 1.5 km
MBS channel reselection interruption time Not specified 1.0 sec (intra-frequency); 1.5 sec (inter-frequency)
Location determination latency <30 sec; MS-based position
Location based services (LBS) Not specified determination accuracy <50 m; Network-based position
determination accuracy <100 m
Up to 40 MHz
Operating bandwidth 5 to 20 MHz (up to 100 MHz through band aggregation)
(with band aggregation)
Duplex scheme Not specified TDD, FDD (support for H-FDD terminals)
Operating frequencies IMT Bands IMT Bands


Source Destination

Application Layer Application Layer

Presentation Layer Presentation Layer

Logical Protocol Links
Session Layer Session Layer

Transport Layer Transport Layer
Layer-3 Signaling

Network Layer Network Layer Network Layer Network Layer

1 2 3 4
User-Plane Latency
User-Plane Latency
Transmit Reference Data-Link Layer Data-Link Layer
Data-Link Layer Data-Link Layer Receive Reference Point
Point

Physical Layer Physical Layer Physical Layer Physical Layer

Intermediate Network Nodes

Logical Data Path

Layer-2 Signaling Radio Air-Interface

The user-plane latency is defined as the one-way transit time between a packet being
available at the IP layer of the origin and the availability of this packet at IP layer of the
destination. The user-plane packet delay includes delay introduced by associated protocols
and signaling assuming the user terminal is in the active-mode.


NAP Visited NSP Home NSP
R2

R1 R3 R5
ASN1 Visited Home
MS CSN
CSN

Control
Plane

Bearer R4
Plane

ASP Network/ ASP Network/
ASN2 Internet Internet

The network reference model is a logical representation of the network architecture. The
NRM identifies functional entities and reference points over which interoperability is
achieved. The WiMAX NRM consists of MS, ASN, and CSN, which are described in the
following sections. The interfaces R1-R8 are normative reference points.


Bearer Path ____
R6 Control Path - - - -
Data Path R1
Authenticatiion
Function ASN-GW BS1
R3
Handover Key R8 ASN-GW1
Function Distribution
R1
RRM Relay R4 BS2
Context Function DHCP Proxy R6
Paging R3 R4
Proxy Mobile Control Service Flow R1 R6
IPClient Authentication BS3
Location
R4
Register Mobile IP FA
AAA Client R8 ASN-GW2
R1
BS4
R6 R6
ASN

Data Path Context Radio Resource
Function Function Agent The ASN comprises network elements
Radio
Resource
such as one or more base stations and
R1 R8
Handover Control Authentication one or more ASN Gateways (ASN-GW).
Function Relay
An ASN may be shared by more than one
Paging Agent
Connectivity Service Networks (CSN). The
Service Flow
Management BS Key Receiver radio resource control functions in the BS
would allow Radio Resource Management
(RRM) within the BS. The CSN is defined
ASN as a set of functions that provide IP
connectivity to user terminals.


CSN
(MIP HA)

R3 R3
Inter-ASN R3 Mobility

ASN-GW R4 ASN-GW
(MIP FA) (MIP FA)

R6 Intra-ASN R6 Mobility R6 R6

R8
BS1 BS2 BS3

Intra-ASN R8 Mobility

MS MS MS MS
Direction of Motion
1 2 3 4

Three different mobility scenarios are supported in WiMAX networks. When the mobile
station moves from positions 1 to 2 or 1 to 3, an ASN-anchored mobility through R8 or R6
reference points, respectively, is involved, whereas moving from position 1 to 4 involves a
CSN-anchored mobility scheme though R3 reference point.


The paging reference model can be decomposed into three separate functional entities:
 Paging Controller administers the activity of an idle-mode MS in the network. It is identified by a
PC Identifier and can either be collocated with the BS or separate from the BS across R6
reference point.
 Paging Agent manages the interaction between the PC and IEEE 802.16 specified paging
related functionality implemented in the BS. A PA is collocated with the BS.
 Paging Group consists of one or more Paging Agents. A Paging Group resides entirely within a
NAP boundary and is managed and provisioned by the network operator.
 Location Register is a distributed database with each instance corresponding to an Anchor PC.
Location registers contain information about mobile stations in Idle State. The information for each
MS includes current Paging Group ID, paging cycle, paging offset, last reported BS Identifier, last
reported Relay PC ID.
Location Location
Register Register

R4
Paging Paging
Controller Controller

BS1 BS2 BS3 BS4 BS5 BS6
Paging Paging Paging Paging Paging Paging
Agent 1 Agent 2 Agent 3 Agent 4 Agent 5 Agent 6

Paging Group 1 Paging Group 2 Paging Group 3


IEEE 802.16 Entity
CS SAP IEEE 802.16 Entity
CS SAP
Service Specific Convergence

Network Control and Management System
Radio Resource Service Specific
Sublayer

Network Control and Management System
Control and Convergence
(CS) Management Sublayer
CS Management/Configuration Functional Group (CS)
MAC SAP
MAC SAP CS Management/Configuration

M-SAP--------------C-SAP

M-SAP--------------C-SAP
Medium Access Control Functional
Group MAC CPS

MAC Common Part Sublayer
(MAC CPS)
MAC Management/Configuration
MAC Management/Configuration

Security Sublayer
Security Sublayer Management Information Base
Management Information Base
(MIB)
(MIB) PHY SAP
PHY SAP

Physical Layer
Physical Layer (PHY)
(PHY)
PHY Management/Configuration
PHY Management/Configuration
Control Plane Data Plane Management Plane
Data/Control Plane Management Plane

IEEE 802.16m reference model is very similar to IEEE 802.16-2009 standard with the exception of soft
classification of MAC common part sub-layer into radio resource control and management and medium access
control functions.

Layer 3
Network Layer

Management SAP and Control SAP

CS-SAP
System
Relay Radio Resource Location
configuration Convergence Sublayer
Functions Management management
management

Mobility Idle Mode
Multi-Carrier MBS
Management Management
Classification

Service flow and
Network-entry Security
Self Organization Connection Header
Management management
Management suppression

Radio Resource Control and Management (RRCM) MAC SAP

Layer 2
Fragmentation/Packing
Medium Access Control (MAC)
ARQ

Multi Radio Sleep Mode Scheduling and
QoS
Coexistence Management Resource Multiplexing

MAC PDU formation
PHY Control

Link Adaptation Control
Data Forwarding Interference Encryption
Ranging (CQI, HARQ, power Signaling
Management
control)

Control-Plane Data-Plane

Layer 1
PHY Protocol (FEC Coding, Signal Mapping, Modulation, MIMO processing, etc.)

Physical Layer


L3
Network Layer

Management SAP and Control SAP

Radio Resource Control and Management (RRCM) CS SAP

System Convergence Sublayer
Relay Radio Resource Location
Configuration
Functions Management Management
Management
Service Flow
Mobility Idle Mode Classification
Multi-Carrier E-MBS
Header
Service flow and Suppression
Network-entry Security
Self Organization Connection
Management

MAC SAP

Scheduling and Resource Multiplexing

L2
Fragmentation/Packing

ARQ

Multi Radio Sleep Mode
QoS
Coexistence Management

PHY Control
MAC PDU Formation
Link Adaptation Control
Data Forwarding Interference
Ranging (CQI, HARQ, power Signaling
Management
control) Encryption

HARQ/CQI
Medium Access Control (MAC) Ranging
Feedback
PHY SAP

PHY Protocol (FEC Coding, Signal Mapping, Modulation, MIMO processing, etc.)

L1
Physical Layer

Control-Plane Data-Plane
Control Primitives between MAC CPS Functions

Control Messages/Signaling (Control Plane)

Data Path (Data Plane)


IP IP
MS Packets Packets
Reports

Convergence
Convergence
Service Flow Classification Service Flow Declassification

Sublayer
Sublayer
Header Compression Header Decompression

Payload Selection and ARQ and ARQ and
Packet Segmentation Packet Reassembly

Sequencing

PDU Formation and PDU Retrieval and
Priority Handling Multiplexing De-multiplexing
Scheduling and Resource Multiplexing

Encryption Dercryption
(MAC)

Retransmission Control HARQ HARQ

Redundancy Redundancy
Version Version

Channel Coding Channel Decoding

Modulation Scheme Data Modulation Data Demodulation

PHY
PHY
MIMO Mode Selection MIMO Encoding MIMO Decoding

Resource/Power Assignment Resource Mapping Resource Demapping

Antenna Mapping Antenna Mapping Antenna Demapping

BS MS


Paging To
Available Mode Access
State
From
To
Connected State
Initialization
State
Paging
Unavailable
Mode

Power Down
Power On/Off

Normal Network Re-Entry/Fast Network Re-Entry

Initialization State
Access State* Connected State Idle State

From Access State,
Connected State, or
Idle State
Scanning and DL
Synchronization
From Initialization Sleep mode
(Preamble Detection)
State or Idle State
Ranging and UL Sleep Listening
synchronization Interval Interval

To Initialization
Broadcast Channel To Access State State Basic Capability
Acquisition Negotiation
Active Mode
Cell Selection From Access
Decision To Idle State
State
MS Authentication,
Authorization & Key
Exchange To Initialization
State
Scanning Mode

Registration with
Serving BS

To Connected
Initial Service Flow State
Establishment


Sleep Request/Sleep
Network Re-entry Process
Response Messages

Active Mode/Scanning
Connected
Idle State Mode Sleep Mode
State
(Normal Operation)

Deregistration Request/ Traffic Indication/Bandwidth
Deregistration Command Request Messages

Upon completion of initial network entry, the MS starts normal operation in the Active Mode
while periodically scanning the neighboring base stations for handover. It may transition to the
Idle State through deregistration messages or exit the Idle State and enter the Active Mode by
performing network re-entry procedures. The MS may transition to the Sleep Mode after
negotiating the sleep intervals with the serving BS and it may exit the Sleep Mode upon
receiving a traffic indication message or availability of uplink traffic.


 The convergence sublayer interfaces with network layer and MAC CPS through CS and MAC
SAPs, respectively and performs the following functions:
◦ Accepting Protocol Data Units (PDUs) from the network layer
◦ Performing classification of higher layer PDUs
◦ Processing the higher layer PDUs based on the classification (i.e., payload header compression)
◦ Delivering CS PDUs to the appropriate MAC Service Access Point (SAP)
◦ Receiving CS PDUs from the peer entity
 The Internet Protocol CS (IPCS) and Generic Packet CS (GPCS) are two types of the service
specific CS that are supported by IEEE 802.16m.
 When using GPCS, the classification is performed in protocol layers above the CS and the
relevant information for performing classification is transparently provided during connection setup
or change.
 The Asynchronous Transfer Mode CS (ATM CS) and Ethernet CS variants that were specified in
IEEE 802.16-2009 standard are no longer supported in IEEE 802.16m due to lack of industry
interest.
SFID1 CIDi1: STIDi+FID1


Network Layer
SFID3 CIDi3: STIDi+FID3 MSi
Classifier

Packets SFID4 CIDi4: STIDi+FID4


SFID6 CIDk1: STIDk+FID1

SFID7 CIDk2: STIDk+FID2 MSk
SFID8 CIDk3: STIDk+FID3
Base Station
Logical MAC Connections

Air-Interface


Six logical identifiers are defined to identify an active user and its associated connections
 Station Identifier (STID): A 12-bit STID assigned to the MS during network entry/re-entry which
uniquely identifies the MS within the coverage area of the serving BS. Each MS registered in the
network is assigned an STID.
 Temporary Station ID (TSTID): This logical identifier is used to protect the mapping between the
STID and the MS MAC address. A TSTID is assigned during initial ranging process. During
registration procedure the BS assigns and transfers an STID to the MS using encrypted
registration response message. The serving BS discards the TSTID when the MS successfully
completes the authentication procedures.
 Flow Identifier (FID): Each MS connection is assigned a 4-bit FID that uniquely identifies the
connections with the MS.
◦ The FIDs identify control and transport connections.
◦ An FID that has been assigned to one DL/UL transport connection cannot be assigned to another DL/UL
transport connection belonging to the same MS.
◦ An FID that has been used for a DL transport connection can be assigned to another UL transport connection
associated with the same MS.
 Deregistration Identifier (DID): The DID uniquely identifies an idle-mode MS for the paging
purposes.
 Context Retention Identifier (CRID): If Deregistration with Content Retention (DCR) mode is
enabled, the network assigns a 72-bit CRID to each MS during network entry or upon handover to
an IEEE 802.16m BS in a mixed-mode operation.
 E-MBS Identifier: A 12-bit value that is used along with a 4-bit FID to uniquely identify a specific E-
MBS flow in an E-MBS zone.


H E Type MSB of Header Content
T C (3 Bits) (11 Bits)

LSB of Header Content MSB of CID
(8 bits) (8 Bits)

MAC Header Payload CRC
LSB of CID Header Checksum Sequence
(8 Bits) (8 Bits)

E
H E Type MSB of Length
Header Content S CI EKS
(19 Bits) T C (6 Bits) (3 Bits)
F

LSB of Length MSB of CID
(8 bits) (8 Bits)
Bandwidth Request Bandwidth Request Uplink Transmit Power
(19 Bits) (11 Bits) (8 Bits)

LSB of CID Header Checksum Sequence
MSB LSB MSB LSB
(8 Bits) (8 Bits)
Incremental/Aggregate Bandwidth Request (BR) Bandwidth Request with Uplink Transmit Power Report

Bandwidth Request CINR Feedback Type Preferred CQI
Reserved (4 Bits)
(11 Bits) (7 Bits) (3 Bits) Period (3 Bits)
Generic MAC Header (GMH)
MSB DCD Change Indicator (1 Bit) LSB MSB FBSS Indicator (1 Bit) LSB

Bandwidth Request and Carrier to Interference plus Noise (CINR) Report Channel Quality Indicator Channel (CQICH) Allocation Request

Uplink Maximum
Preferred
Uplink Transmit Power Transmit Power Bandwidth Request Power Saving Class
DIUC Index
(8 Bits) Headroom in dB (11 Bits) (6 Bits)
(3 Bits)
(6 Bits)

MSB LSB MSB Power Class Activation (1 Bit) LSB
Reserved (1 Bit)
Reserved (1 Bit)
Physical Channel Report Bandwidth Request and Uplink Sleep Control Report

ARQ Block Serial Number/
Reserved
MAC SDU Serial Number
(8 Bits)
(11 Bits)
Signaling MAC Header
MSB LSB

ARQ Block Serial Number (BSN) or MAC SDU Serial Number (SN)


 The IEEE 802.16m specifies three types of MAC headers:
◦ Advanced Generic MAC Header (AGMH) that is used for MAC PDUs containing either MAC
management messages or user payload
◦ Short-Packet MAC Header (SPMH) that is utilized in conjunction with persistent or group
allocations
◦ Signaling MAC header
 The MAC header formats are mutually exclusive and are not used simultaneously for
the same connection.
Extended Header Type Usage

MAC SDU Fragmentation Extended Header (FEH) Fragmentation of large MAC SDUs

MAC SDU Packing Extended Header (PEH) Packing of small MAC SDUs

MAC Control Extended Header (MCEH) Transmission and fragmentation of control messages

Multiplexing Extended Header (MEH) Multiplexing of different connections on the same MAC PDU

MAC Control ACK Extended Header (MAEH) Acknowledgement of MAC control message

Piggyback Bandwidth Request Extended Header (PBREH) Piggyback bandwidth request

MAC PDU length extended header (MLEH) Extension of the size of MAC PDUs for large PDUs.

ARQ Feedback Extended Header (AFEH) ARQ feedback

Rearrangement Fragmentation and Packing Extended Header
ARQ feedback for fragmented/packed MAC PDUs
(RFPEH)

ARQ Feedback Polling Extended Header (APEH) ARQ feedback


EH
MAC PDU Length Extension
Extended Length Extended Header Group Length (4 bits)
Flow ID (4 bits) Header Length (3 bits) (3 bits)
(1 bit)
(1 bit)

Length (8 bits) Extended Header Content 1
Extended Header Type 1 (4 bits)
(Variable Length)

Advanced Generic MAC Header (AGMH) Extended Header Content 1
(Variable Length)

Extended Header Group Length
Extended
Flow ID (4 bits) Header Length (3 bits)
(1 bit) Extended Header Content 2
Extended Header Type 2 (4 bits)
(Variable Length)
Length (4 bits) Sequence Number (4 bits)

Extended Header Content 2
(Variable Length)
Short Packet MAC Header (SPMH)

Extended Header Content N
Extended Header Type N (4 bits)
(Variable Length)

Extended Header Content N
(Variable Length)

Extended Headers


MAC signaling headers are different type of headers that are used in MAC PDUs with no payload. They are
sent as standalone or concatenated with other MAC PDUs.
MAC Signaling Header Type Usage
Bandwidth Request with STID Bandwidth Request
Bandwidth Request without STID Bandwidth Request

Service Specific Scheduling Control Change or acknowledge of the scheduling or QoS parameters

Sleep Control Configuration of sleep mode operation parameters

MS Battery Level Report Terminal’s battery level reporting
Uplink Power Status Report Uplink power control status reports
Correlation Matrix Feedback Correlation matrix based precoding
MIMO Feedback MIMO feedback

Flow ID Signaling Header Type Length
(4 Bits) (5 Bits) (3 Bits)

Signaling Header Content (Size < 36 bits)


Extended FEH/PEH/ Connection
AGMH
Header(s) RFPEH/MCEH Payload

MAC PDU with Single Connection Payload

EH
Flow ID (4) = x Length (3)
(1)

Length (8)

FEH/PEH/ FEH/PEH/ Connection Connection
Extended
AGMH MEH RFPEH and RFPEH and Payload Payload
Header(s)
MCEH (flow x) MCEH (flow y) Flow ID=x Flow ID=y

NI_FI
Type (4 bits)
(4 bits)

FID (4 bits), LI (1 bit), Length (11 or 14 bits), Reserved (1 bit)

FID (4 bits), LI (1 bit), Length (11 or 14 bits), Reserved (1 bit)

EH Indicator Bitmap (Variable)

MAC PDU with Multiple Connections Payload

The MAC PDU contains a variable-sized payload. Multiple MAC SDUs and/or SDU fragments
from different unicast connections corresponding to the same MS can be multiplexed into a
single MAC PDU. The multiplexed unicast connections are associated with the same security
association.


MS BS

DL Synchronization

AAI_RNG-REQ
(MS ID* is transmitted over the air)

AAI_RNG-RSP
(TSTID is assigned by the BS)

Basic Capability Negotiation

MS Authentication and Authorization

Key Exchange

AAI_RNG-REQ
(MS ID is transmitted over the air)

AAI_RNG-RSP
(STID is assigned by the BS)

Data and Control Plane Establishment


MS Serving BS Target BS

HO-REQ

HO-RSP
BS Initiated HO
HO-CMD

HO-REQ

HO-REQ
MS Initiated HO
HO-RSP

HO-CMD

HO-IND

Network Re-entry with Target BS
Data Communication
with Serving BS
during Network Re-entry HO-COMPLT

Data Plane Re-established

In IEEE 802.16m, the handover process may be initiated by either the MS or the BS.


The IEEE 802.16-2009 standard defines four basic mechanisms for handover:
 Hard Handover (HHO):
◦ A process that is based on Received Signal Strength Indicator (RSSI)
measurements conducted on the preamble. The MS continuously measures the
RSSI of the serving BS and reports the values periodically to the serving BS. The
neighbor base stations are advertised periodically by the serving BS through a
broadcast MOB_NBR-ADV message. During the scanning period, user data is not
exchanged between the MS and the serving BS; instead the MS receives the
preambles from the each neighbor and calculates the RSSI.
 Fast Base Station Switching (FBSS):
◦ The MS and BS both maintain a list of the base stations (i.e., Diversity Set) that
are involved in FBSS operation. An Anchor BS, with which the MS only
communicates, is defined in the set. The MS may add or drop a BS to or from the
list. The Anchor BS may be changed by using HO messages or by using fast
anchor selection feedback. The measurements are based on Carrier to
Interference-plus-Noise Ratio (CINR) calculations conducted on the pilot
subcarriers in DL and UL subframes.


MS Serving BS Target BS (No 1) Target BS (No 2)

MOB_NBR-ADV

MOB_SCN-REQ

MOB_SCN-RSP

CDMA Code

Scanning Interval
Anonymous RNG-RSP
(No Data Traffic)

RNG-REQ

RNG-RSP

Scan BS No 2

MOB_SCN-REP

MOB_MSHO-REQ

MOB_BSHO-RSP

MOB_MSHO-IND

Network Re-entry with BS No 2


MS Anchor BS Target BS

MOB_NBR-ADV Receive Neighbor BS
Parameters and Compare
MOB_SCN-REQ Measured CINRs to Thresholds

MOB_SCN-RSP

CDMA Code

Anonymous RNG-RSP

RNG-REQ

RNG-RSP

MOB_MSHO-REQ

MOB_BSHO-RSP
Compare Measured
CINRs to Thresholds and
MOB_MSHO-REQ Update Diversity Set

MOB_BSHO-RSP

Update Anchor BS
MOB_MSHO-IND
to Target BS


 Macro Diversity Handover (MDHO):
◦ An MDHO process is initiated with a decision for an MS to transmit to and receive from
multiple base stations at the same time.
◦ For an MS and a BS that support MDHO, the MS and the BS maintain a list of BSs that are
involved in MDHO with the MS. The list is called the Diversity Set.
◦ Among the base stations in the Diversity Set, an Anchor BS is defined. The normal operation
where the MS is registered with a single BS is a particular case of MDHO with Diversity Set
consisting of a single BS; the Anchor BS.
◦ When operating in MDHO, the MS communicates with all base stations in the Diversity Set for
UL and DL unicast messages and traffic. There are two methods for the MS to monitor DL
control information and broadcast messages. In the first method, the MS monitors only the
Anchor BS for DL control information and broadcast messages. In the second method, the MS
monitors all the base stations in the Diversity Set for DL control information and broadcast
messages.
 Seamless Handover:
◦ In addition to optimized HHO, MS and BS may perform seamless HO, which is a variant of
HHO, to reduce HO latency and message overhead.
◦ The seamless HO is only enabled if the MS, the serving BS, and the target base stations
support seamless HO. A BS supporting seamless HO must include the connection identifier
descriptor in the system information.


MS Serving BS Target BS

HO-REQ
CID and TEK Pre-update
HO-RSP
Action
Time Seamless HO
HO-IND (BS-ID) Initiation Decline

Unicast Encrypted DL Data, UL Grant

BW-REQ, Unicast Encrypted UL Data

RNG-REQ (CMAC)

Target BS RNG-RSP (CMAC)
Becomes
Serving BS Completion of
BW-REQ (0)
Seamless HO


The HO process consists of the following stages:
 Cell Reselection: the MS may use neighbor BS information acquired from a decoded
MOB_NBR-ADV message or may request to schedule scanning intervals or sleep intervals to
scan neighbor base stations for the purpose of handover to a potential target BS.
 HO Decision and Initiation: the HO process begins with a decision for an MS to HO from a
serving BS to a target BS. The decision may originate either at the MS or at the serving BS.
 Downlink Synchronization: the MS synchronizes to the DL transmissions of the target BS and
obtains system configuration information.
 Ranging: the MS and target BS must perform initial ranging or HO ranging. If the RNG-REQ
message includes the serving BS-ID, then the target BS may request the serving BS to provide
the MS information over the backhaul. The normal network re-entry process may be simplified by
target BS possession of MS information.
 Termination of MS Context: the final step in HO is termination of MS context that is defined as
serving BS termination of context of all connections belonging to the MS and the context
associated with them (i.e., information in queues, ARQ state machine, counters, timers, header
suppression information, etc., is discarded).
 HO Cancellation: an MS may cancel HO via MOB_HO-IND message at any time prior to
expiration of Resource_Retain_Timer after transmission of MOB_MSHO-REQ (in case of MS-
initiated HO) or MOB_BSHO-REQ (in case of BS-initiated HO).


Select Alternative Target
Initiate Cell Selection
BS

DL Synchronization and New DL Synchronization
System Information and System Information
Acquisition Acquisition
(DL/UL Parameters) (New DL/UL Parameters)

Cell Rejected Cell Rejected

Ranging and UL Ranging and UL
Synchronization Synchronization
Cell Rejected Cell Rejected

Basic Capability Negotiation MS Re-authorization

Cell Rejected

MS Authorization and Key
Re-registration and
Exchange
Cell Rejected

Reestablishment of Service
Registration with BS
Flows

IP Connection IP Connection
Normal Operation
Establishment Reestablishment

Operations with the Base Station

Transfer of Operational
Parameters

HO Execution
Connection Establishment

Cell Reselection
Scanning Intervals
for Detecting and Normal Operation
Evaluating Neighbor
Cells

HO Decision


MS Serving BS Target BS MS Serving BS Target BS

AAI_HO-REQ AAI_HO-REQ

AAI_HO-CMD AAI_HO-CMD
Action Time

Action Time
AAI_HO-IND AAI_HO-IND

HO Ranging Initiation Deadline

HO Ranging Initiation Deadline
(Dedicated) CDMA Ranging Code (Dedicated) CDMA Ranging Code

Disconnect Time
AAI_RNG-ACK AAI_RNG-ACK

Maintain Data Communication
Unicast Encrypted DL Data/UL Grant with the Serving BS during
Network Re-entry

Unicast Encrypted UL Data/Bandwidth Request

AAI_RNG-REQ (CMAC) AAI_RNG-REQ (CMAC)

AAI_RNG-RSP (CMAC) AAI_RNG-RSP (CMAC)

Completion of Network Re-entry and HO Completion of Network Re-entry and HO

Network Re-entry Procedures when Entry-Before-Break Disabled Network Re-entry Procedures when Entry-Before-Break Enabled


 For handover from a new serving to a legacy target BS, the legacy MS detaches from the legacy
zone of the serving BS to the target BS using legacy handover signaling and procedures.
 For handover from a new BS to a legacy BS, the new MS detaches from the serving BS and
performs handover procedures specified by IEEE 802.16m. The MS performs network re-entry
with target legacy BS using network re-entry procedures specified in IEEE 802.16-2009 standard.
 An MS performs handover from a legacy BS to a new BS by using either zone-switching or direct
handover process.
◦ The zone-switching handover is applicable to new base stations supporting coexisting legacy and new system.
◦ The direct handover is applicable to new base stations which only support new mobile stations. A new BS may
also decide to keep a new MS in the legacy zone when coexist-ing with legacy systems.
Serving Serving
MS Target New BS MS Target New BS
Legacy BS Legacy BS

LZone MZone LZone MZone

MOB_MSHO-REQ MOB_MSHO-REQ

MOB_BSHO-RSP MOB_BSHO-RSP

MOB_HO-IND MOB_HO-IND
(Target BS-ID) (Target BS-ID)

RNG-REQ RNG-REQ

RNG-RSP RNG-RSP

RNG-RSP (including Zone-Switching Parameter) Data Path Established

Synchronization with MZone RNG-RSP (including Zone-Switching Parameter)

AAI_RNG-REQ
Synchronization with MZone
Ranging Purpose Indication = Zone Switch

AAI_RNG-REQ
AAI_RNG-RSP
Ranging Purpose Indication = Zone Switch

Data Path Established AAI_RNG-RSP

Data Path Established

The Target BS Instructs the MS to Switch Zone during Network Re-entry The Target BS Instructs the MS to Switch Zone after Network Re-entry


Delay Bit Error Rate
Service Class Categories Bit Rate Use Cases
Requirement (BER) Margin
Tele-presence/Video-conference,
Point to Multi-Point, Multi-Point to
Collaborative work Navigation systems,
Multi-Point, Multi-Point to Point, < 20 ms 1 - 20 Mbps 10-9 ≤ BER ≤ 10-6
Real-time Gaming, Real-time video
Highly Interactive
streaming
Asymmetric, Interactive, Low Remote Control Sensors, Interactive
20 – 100 ms 8 - 512 kbps 10-9 ≤ BER ≤ 10-6
Rate geographical maps
Point to Multi-Point, Multi-Point to Rich data call, Video
Multi-Point, Multi-Point to Point, 20 – 100 ms 1- 50 Mbps 10-6 ≤ BER ≤ 10-3 broadcasting/streaming, High quality video
Interactive, High Rate conference, Collaborative work
Voice telephony, Instant messages,
Multiplayer gaming, Audio streaming, Video
Conversational, Soft BER 100 - 200 ms 8 - 512 kbps BER ≤ 10-3
telephony (medium quality) Multiplayer
gaming (high quality)

Conversational, Symmetric QoS, High quality video telephony, Collaborative
100 - 200 ms 1 - 50 Mbps 10-6 ≤ BER ≤ 10-3
Tight BER work, Access to databases, file systems

Messaging (data/voice/media),
Point to Point Unidirectional Web browsing, Audio on demand, Internet
8 kbps – 50
(Uplink or Downlink), > 200 ms 10-9 ≤ BER ≤ 10-6 radio, Access to databases, Video
Mbps
Asymmetric, Delay Tolerant download/upload, Peer-to-peer file sharing,
Video streaming


 There are three types of service flows as follows:
◦ Provisioned: This type of service flow is provisioned by the network management
system and its AdmittedQoSParamSet and ActiveQoSParamSet attributes are
both null.
◦ Admitted: This type of service flow has resources reserved by the BS for its
AdmittedQoSParamSet, but these parameters are not active (i.e., its
ActiveQoSParamSet is null). The admitted service flows may be provisioned by
other mechanisms in the network.
◦ Active: This type of service flow has resources committed by the BS and its
ActiveQoSParamSet attribute is non-empty.

AuthorizedQoSParamSet
(BS only)

AdmittedQoSParamSet
(SFID and CID)

ProvisionedQoSParamSet
(SFID)
ActiveQoSParamSet
(SFID and Active CID)

Relationship between the QoS Parameter Sets

 Uplink/Downlink Indicator parameter identifies service flow direction relative to the originating
entity.
 Maximum Sustained Traffic Rate is a parameter that defines the peak information rate of the
service. The rate is expressed in bits per second and pertains to the service data units at the input
to the system. This parameter does not limit the instantaneous rate of the service since this is
governed by the physical attributes of the entrance port.
 Maximum Traffic Burst parameter defines the maximum burst size that is accommodated for the
service. Since the physical rate of input/output ports, any air-interface, and the backhaul will in
general be greater than the maximum sustained traffic rate parameter for a service, this
parameter describes the maximum continuous burst the system should accommodate for the
service assuming the service is not currently using any of its available resources.
 Minimum Reserved Traffic Rate parameter specifies the minimum rate, in bits per second,
reserved for this service flow. The BS is required to satisfy the bandwidth requests for a
connection up to its minimum reserved traffic rate The value of this parameter excludes the MAC
overhead.
 Maximum Latency is a parameter, whose value specifies the maximum interval between
reception of a packet at the convergence sublayer of the BS or MS and the transmission of the
corresponding physical layer PDU over the air-interface. A value of zero for maximum latency is
interpreted as no commitment.
 SDU Indicator is a parameter whose value specifies whether the SDUs are fixed or variable
length.


 Paging Preference is a single bit indicator of a mobile station’s preference for the reception of
paging advisory messages during the Idle State. It indicates that the BS may present paging
advisory messages or other indicators to the MS, when there are MAC SDUs bound for an idle
mode MS.
 Uplink Grant Scheduling Type specifies which uplink grant scheduling service type is
associated with uplink service flow. This parameter is present in the uplink direction.
 Tolerated Jitter is a parameter whose value specifies the maximum delay variation (jitter) for the
connection. This parameter is present for a DL or UL service flow, which are associated with
Uplink Grant Scheduling Type = UGS or ertPS.
 Request/Transmission Policy is a parameter whose value specifies certain attributes for the
associated service flow.
 Traffic Priority is a parameter whose value specifies the priority of associated service flow. This
parameter is present for a DL or UL service flow, which are associated with any Uplink Grant
Scheduling Types except UGS.
 Unsolicited Grant Interval parameter defines the nominal interval between successive data
grant opportunities for a DL service flow, which are associated with Uplink Grant Scheduling Type
= UGS or ertPS.
 Unsolicited Polling Intervals parameter defines the maximum nominal interval between
successive polling grants opportunities for a UL service flow, which are associated with Uplink
Grant Scheduling Type = rtPS.


 Unsolicited Grant Service (UGS) is designed to support real-time uplink service flows that
transport periodic fixed-size data packets such as VoIP without silence suppression. This service
class provides fixed-size grants on a real-time periodic basis, which eliminates the overhead and
latency due to MS bandwidth requests and ensures timely availability of the grants to meet the
real-time characteristics of the service flow.
 Real-Time Polling Service (rtPS) is designed to support real-time UL service flows that transport
variable-size data packets on a periodic basis such as MPEG video format. This service offers
real-time, periodic, and unicast request opportunities, which meet the service flow’s real-time
requirements and further allow the MS to specify the size of the desired grant. This service
involves more overhead than UGS, but supports variable-sized grants for optimal data transport.
 Extended Real-Time Polling Service (ertPS) is a scheduling mechanism which utilizes the
advantages of UGS and rtPS. The BS provides unicast grants in an unsolicited manner similar to
UGS, reducing the latency of bandwidth request. Unlike the UGS allocations, the ertPS
allocations are variable-sized.
 Non-Real-Time Polling Service (nrtPS) offers unicast polls on a regular basis, which ensures
that the UL service flow receives request opportunities even during network congestion. The
serving BS typically polls nrtPS connections every one second and provides timely unicast
request opportunities.
 Best Effort (BE) service is designed to support applications for which no minimum service
guarantees (e.g., no rate or delay requirements) are required. The MS is allowed to use
contention-based and unicast request opportunities for data transmission.


 In addition to the legacy service class attributes, IEEE 802.16m defines a new service class
attribute called Maximum Sustained Traffic Rate per Flow.
 The new attribute defines the peak information rate of the service flow. The maximum rate is
denoted in bits per second and pertains to the service data units at the input of the convergence
sublayer.
 This parameter does not include transport, protocol, or network overhead information and does
not limit the instantaneous rate of the service flow since this is governed by the physical attributes
of the ingress port. However, at the destination network interface in the uplink direction, the
service is regulated to ensure conformance to this parameter. The time interval over which that
the traffic rate is averaged is defined during service negotiation. In the downlink direction, it may
be assumed that the service was already regulated at the ingress to the network. If this parameter
is set to zero, then there is no explicitly mandated maximum rate. The maximum sustained traffic
rate field specifies only a bound, not a guarantee that the rate is available.
 Adaptive Grant and Polling Service (aGPS) is a new service class defined in IEEE 802.16m
where the BS may grant or poll an MS periodically and may negotiate only primary QoS
parameters or both primary and secondary QoS parameter sets with the MS.
◦ Initially, the BS uses QoS parameters defined in the primary QoS parameter set including primary Grant and
Polling Interval (GPI) and primary Grant Size. During the service, the traffic characteristics and QoS
requirement may change.
◦ Adaptation includes switching between primary and secondary QoS parameter sets or changing of GPI/Grant
size to values other than those defined in the primary or second-ary QoS parameter sets when the traffic can
be characterized by more than two QoS states.


QoS Class Applications QoS Parameters
UGS Maximum sustained rate, Maximum latency tolerance, Jitter
VoIP
Un-Solicited Grant Service tolerance
rtPS Minimum Reserved Rate, Maximum Sustained Rate,
Streaming Audio, Video
Real-Time Packet Service Maximum Latency Tolerance, Traffic Priority
ErtPS
Voice with Activity Minimum Reserved Rate, Maximum Sustained Rate,
Extended Real-Time Detection (VoIP) Maximum Latency Tolerance, Jitter Tolerance, Traffic Priority
Packet Service
nrtPS
Minimum Reserved Rate, Maximum Sustained Rate, Traffic
Non-Real-Time Packet FTP
Priority
Service
BE Data Transfer, Web
Maximum Sustained Rate, Traffic Priority
Best-Effort Service Browsing
aGPS
Maximum Sustained Traffic Rate, the Request/Transmission
Adaptive Granting and Application Agnostic
Policy, Primary Grant and Polling Interval, Primary Grant Size
Polling


 An ARQ block is generated from one or multiple MAC SDUs or MAC SDU fragments
corresponding to the same flow.
 The ARQ blocks can be variable in size.
 An ARQ block is constructed by fragmenting MAC SDU or packing MAC SDUs and/or MAC SDU
fragments. The fragmentation or packing information for the ARQ block is included in the
extended header within MAC PDU.
 When a MAC PDU is generated for transmission, the MAC PDU may contain one or more ARQ
blocks. If the MAC PDU contains traffic from a single connection, the MAC PDU itself will be a
single ARQ block. If information from multiple ARQ connections is multiplexed into one MAC
PDU, the MAC PDU contains multiple ARQ blocks.
 The number of ARQ blocks in a MAC PDU is equal to the number of ARQ connections
multiplexed in the MAC PDU.
 The ARQ blocks of a connection are sequentially numbered. The ARQ block Sequence Number
(SN) is included in MAC PDU using a FPEH or MEH headers. The original MAC SDU ordering is
maintained. In the legacy system, the size of the ARQ blocks is fixed and the length of the ARQ
blocks is specified by the serving BS for each connection and signaled through MAC
management messages. In that case, if the length of the MAC SDU is not an integer multiple of
ARQ block size, the last ARQ block may be padded. The MAC SDU partitioning into ARQ blocks
remains in effect until all ARQ blocks are received and acknowledged by the receiver.
 If the initial transmission of an ARQ block fails, a retransmission is scheduled with or without
rearrangement. In case of ARQ block retransmission without rearrangement, the MAC PDU
contains the same ARQ block and corresponding fragmentation and packing information, which
was used in the initial transmission.


ACK
DONE

ACK ACK
Retransmission with
Retransmission without Rearrangement
Rearrangement

WAITING FOR
NOT SENT Transmit OUTSTANDING RETRANSMISSION
ACK REARRANGEMENT

NACK

ARQ_BLOCK_LIFETIME ARQ_BLOCK_LIFETIME

DISCARD
ARQ_BLOCK_LIFETIME


MAC SDU 1 MAC SDU 2 MAC SDU 3 MAC SDUs

ARQ Block 1 ARQ Block 2 ARQ Blocks

1st 2nd 3rd 1st 2nd 3rd 4th
Sub-block Sub-block Sub-block Sub-block Sub-block Sub-block Sub-block
ARQ Block1 ARQ Block2 ARQ Sub-blocks
ARQ ARQ ARQ ARQ ARQ ARQ ARQ
Block 1 Block 1 Block 1 Block 2 Block 2 Block 2 Block 2

MAC PDU 1 MAC PDU 2
st nd
1 2 3rd 1st 2nd 3rd 4th
PEH 1st Fragment of
Sub-block Sub-block PEH Sub-block 2nd Sub-block Sub-block
Sub-block Fragment of ARQ Sub-block MAC PDUs
AGMH AGMH
(SN 1) ARQ Block1
ARQ ARQ (SN 2) ARQ ARQ Block1 +ARQ Block 2
ARQ ARQ ARQ (1st Transmissions)
Block 1 Block 1 Block 1 Block 2 Block 2 Block 2 Block 2

Successful Transmission Failed Transmission

MAC PDU 3 MAC PDU 4
rd st nd
3 1 2 3rd 4th
RFPEH FPEH
Sub-block Sub-block Sub-block Sub-block Sub-block
AGMH (SN 2, AGMH (SN 2,
ARQ ARQ ARQ ARQ ARQ
SSN 1) SSN 3)
Block 1 Block 2 Block 2 Block 2 Block 2

Retransmission of MAC PDU 2 with Rearrangement

MAC PDU 3
rd
3 1st 2nd 3rd 4th
PEH Sub-block 2nd Sub-block Sub-block
Sub-block Fragment of ARQ Sub-block
AGMH
(SN 2) ARQ ARQ Block1 +ARQ Block 2
ARQ ARQ ARQ
Block 1 Block 2 Block 2 Block 2 Block 2

Retransmission of MAC PDU 2 without Rearrangement


 In order to achieve increased throughput and lower latency in packet transmission, HARQ
scheme is designed to combine ARQ error-control mechanism and FEC coding. It consists of a
FEC subsystem contained in an ARQ system. In this approach, the average number of
retransmissions is reduced by using FEC through correction of the error patterns that occur more
frequently; however, when the less frequent error patterns are detected, the receiver requests a
retransmission where each retransmission carries the same or some redundant information to
help the packet detection.
 HARQ uses FEC to correct a subset of errors at the receiver and rely on error detection to detect
the remaining errors. Most practical HARQ schemes utilize CRC codes for error detection and
convolutional or Turbo codes for error correction.
 HARQ mechanism is used for all unicast data traffic in both downlink and uplink.
 The IEEE 802.16m HARQ scheme is based on an N-process stop-and-wait protocol. The N-
process stop-and-wait mechanism makes use of the waiting time and transmits other sub-
packets. Both BS and MS are required to maintain multiple simultaneous HARQ channels. The
DL HARQ channels are identified by HARQ Channel Identifier (ACID), whereas the UL HARQ
channels are identified by both ACID and the index of UL subframe in which UL HARQ data burst
is transmitted.
 The received sub-packets are combined by the FEC decoder as part of the decoding process.
The use of incremental redundancy HARQ is mandatory in IEEE 802.16m compliant. Each sub-
packet contains part of codeword identified by an SPID. In order to specify the start of a new
transmission, a single-bit HARQ Identifier Sequence Number (AI_SN) is toggled on every new
HARQ transmission attempt on the same ACID.


Frame N Frame N+1
Subframe

DL S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 S5 S6 S7

Assignment Assignment
+ DL Burst + DL Burst

UL S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 S5 S6 S7

HARQ HARQ
Feedback Feedback
Example FDD DL HARQ Timing
Frame N Frame N+1
Subframe

S0 S1 S2 S3 S4 S0 S1 S2 S3 S4
DL DL DL DL DL DL DL DL DL DL

Assignment Assignment
+ DL Burst + DL Burst

S5 S6 S7 S5 S6 S7
UL UL UL UL UL UL

HARQ HARQ
Feedback Feedback

Example TDD DL HARQ Timing

The IEEE 802.16m uses adaptive asynchronous HARQ in the downlink. In adaptive asynchronous HARQ, the
resource allocation and transmission format for the HARQ retransmissions may be different from the initial
transmission. In case of retransmission, appropriate signaling is required to indicate the resource allocation and
transmission format along with other HARQ parameters.


Frame N Frame N+1
Subframe

DL S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 S5 S6 S7

Assignment + HARQ
Assignment
Feedback

UL S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 S5 S6 S7

UL Burst UL Burst
Example FDD UL HARQ Timing
Frame N Frame N+1
Subframe

S0 S1 S2 S3 S4 S0 S1 S2 S3 S4
DL DL DL DL DL DL DL DL DL DL

Assignment + HARQ
Assignment
Feedback

S5 S6 S7 S5 S6 S7
UL UL UL UL UL UL

UL Burst UL Burst

Example TDD UL HARQ Timing

The IEEE 802.16m uses a synchronous HARQ scheme in the uplink where the interval between successive
transmissions/retransmissions is the same, resulting in less overhead in resource assignment. In synchronous
HARQ, resource allocation for the retransmissions in the uplink can be fixed or adaptive according to control
signaling. The default operation mode of HARQ in the uplink is non-adaptive.


Convergence Sublayer

 The payloads associated with multiple transport MAC Control Functions Service Flow Classification
connections corresponding to the same security Header Suppression
association can be multiplexed and encrypted
together in a MAC PDU.

Control for MAC Signaling Headers
Messages Messages MAC SDU MAC SDU MAC SDU MAC SDU

 If N transport connections are multiplexed, one
MEH and N FPEH and/or FEH are present in a Fragmentation SDU Fragmentation/Packing Function

MAC PDU.
 The AGMH and the MEH headers carry the
MAC PDU
ARQ
MAC PDU MAC PDU MAC PDU
information about the Flow IDs and lengths of Payload Payload Payload Payload
MAC PDU MAC PDU
the payloads. Payload Payload

 The FPEH and FEH headers carry the MPDU Formation
information about the transport and
management connections’ payload, Multiplexing Security (Encryption/Authentication)

respectively.
 Multiple MAC PDUs may be concatenated into a MAC PDUs

single transmission in UL or DL directions. For
Concatenation Function
the MS attached to a BS, each MAC PDU in an
UL or DL PDU is uniquely identified by a Flow Concatenated MAC PDUs

ID. The MAC PDUs containing control Physical Layer

messages, user data, and bandwidth request
MAC CPS Data Plane
may be concatenated into the same Functional Blocks

transmission. Control Connection

Transport Connections (ARQ)

Transport Connections (non ARQ)


Convergence Sublayer

MAC SDUs MAC SDUs
Flow ID = A Flow ID = B

Unencrypted Payload A Unencrypted Payload B

Integrity Check
PN, EKS Encrypted Payload A Encrypted Payload B
Value (ICV)

Unencrypted
Encrypted PDU
Headers

Other Extended Integrity Check
AGMH MEH PN,EKS Encrypted Payload A Encrypted Payload B
Headers Value (ICV)

Unencrypted Headers Encrypted PDU

Multiplexing of Connection Payloads Associated with the Same Security Association


 The connection-oriented MAC layers in the serving BS and the MS communicate using the MAC
control messages to perform the control-plane functions.
 The MAC control messages are contained in MAC PDUs and are transported over broadcast,
unicast, or random access connections.
 There is a single unicast control connection. In order to improve reliability, the HARQ mechanism
is used for MAC control messages that are sent over unicast control connections.
 The IEEE 802.16m MAC control messages can be fragmented.
 The MAC management messages in IEEE 802.16m are distinguished from their legacy
counterparts by an “AAI” prefix denoting the “Advanced Air-Interface” messaging.
 Unlike IEEE 802.16-2009 standard, the IEEE 802.16m MAC control messages are encoded in
ASN.1 format.
 The MAC management messages may or may not be encrypted depending on their function. A
MAC management message included in a MAC PDU whose encryption control bit value does not
match the combined message type and corresponding context is discarded.
 The MAC management messages are grouped based on their usage; e.g., Network entry/re-entry,
Sleep Mode operation, Idle Mode operation, etc.
 The legacy MAC management messages, depending on their types, are carried over basic or
primary management connections as well as broadcast or initial ranging connections, whereas in
IEEE 802.16m, the type of connections for carrying MAC control messages are classified as
unicast, broadcast, and initial ranging.


IEEE 802.16-2009 Standard
IEEE 802.16m MAC Management
Usage Equivalent Connection Type
Message
Message
Broadcast of system information and
AAI_SCD
parameters (Additional Broadcast N/A Broadcast
System Configuration Descriptor
Information)
AAI-LBS-ADV
Broadcast of system information N/A Broadcast
LBS Advertisement
AAI_RNG-REQ
Network Entry/Re-entry RNG-REQ Initial Ranging or Unicast
Ranging Request
AAI_RNG-RSP
Network Entry/Re-entry RNG-RSP Initial Ranging or Unicast
Ranging Response
AAI_RNG-ACK
Network Entry/Re-entry N/A Broadcast
Ranging Acknowledgement
AAI_SBC-REQ
Network Entry/Re-entry SBC-REQ Unicast
MS Basic Capability Request
AAI_SBC-RSP
Network Entry/Re-entry SBC-RSP Unicast
MS Basic Capability Response

AAI_PKM-REQ
Network Entry/Re-entry PKM-REQ Unicast
Privacy Key Management Request

AAI_PKM-RSP
Network Entry/Re-entry PKM-RSP Unicast
Privacy Key Management Response
AAI_REG-REQ
Network Entry/Re-entry REG-REQ Unicast
Registration Request
AAI_REG-RSP
Network Entry/Re-entry REG-RSP Unicast
Registration Response
AAI_RES-CMD
Network Entry/Re-entry RES-CMD Unicast
Reset Command


 A session is defined as the duration of time from the moment that an MS performs initial network
entry and registers with the network and an exclusive MS context is generated in the network until
the MS signs off the network and the MS context is flushed out. During this time, the MS may
transit between different states and may perform a number of network re-entries and re-register
with the serving BS upon transition from Idle to Connected State.
 In the legacy standard, a connection is defined as unidirectional mapping between base station
and mobile station MAC layers. Connections are identified by a 16-bit connection identifier. There
are two types of connections; i.e., management and transport connections, where the
management connections can be of basic, primary, or secondary type.
◦ The basic connection is used by the BS and MS MAC layers to exchange short and time-sensitive MAC
control messages. The primary management connection is utilized by the BS and MS MAC layers to
exchange long and delay-tolerant MAC control messages.
 In IEEE 802.16m, a connection is defined as a mapping between MAC layers of a BS and one or
more mobile stations. When the mapping is between a BS and an MS, the connection is called a
unicast connection. Otherwise, it is a multicast or broadcast connection.
◦ Unicast connections are identified by the combination of a 12-bit STID and a 4-bit FID. Multi-cast and
broadcast connections are identified by the reserved STIDs. In IEEE 802.16m, the connections can
alternatively be classified as management connections and transport connections. Management connections
carry MAC control messages. Transport connections, on the other hand, are used to carry user data includ-ing
upper layer signaling such as DHCP as well as data-plane signaling such as ARQ feedback.
 There is a difference between the notion of connection in IEEE 802.16m and the legacy standard.
In IEEE 802.16m, connections are either management (bi-directional for unicast and
unidirectional for broadcast connections) or transport (unidirectional).


 The transport connections can be added, changed, or deleted as follows:
◦ Dynamic Service Addition
 A set of MAC management messages for addition of a new service flow and
thereby a new transport connection
◦ Dynamic Service Change
 A set of MAC management messages for changing the parameters of an
existing service flow
◦ Dynamic Service Deletion
 A set of MAC management messages for deleting an existing service flow
 To support Emergency Telecommunications Service (ETS) and E-911, the
emergency service flows are given priority in admission control over the
regular service flows.


 Sleep is a mode in which an MS conducts pre-negotiated periods of absence from the serving BS
air-interface.
 Sleep mode is intended to minimize MS power usage and decrease usage of serving BS radio
resources. A single power saving class for each mobile station is managed in order to operate the
active connections associated with the MS.
 The Sleep Mode may be invocated when an MS is in the Connected State. When Sleep Mode is
activated, the MS is provided with a series of alternate listening window and sleep intervals. The
listening window is the time in which the MS is available to exchange control signaling as well as
data in the uplink or downlink.
 The IEEE 802.16m provides a mechanism for dynamically adjusting the duration of sleep
windows and listening windows based on changing traffic patterns and HARQ operations. The
length of successive sleep cycles, each comprising a sleep and listening window, may remain
unchanged or may change based on traffic conditions.
 The sleep and listening windows can be dynamically adjusted for the purpose of data
transmission as well as MAC control signaling. The MS can send and receive data and MAC
control signaling without deactivating the Sleep Mode.
 Sleep Mode entry is initiated either by the MS or the BS. When the MS is in Active Mode, sleep
parameters are negotiated between the MS and BS. The serving BS determines when the MS
can transition to the Sleep Mode. The sleep cycle is measured in units of frames. The start of the
listening windows is aligned with the frame boundaries. The MS ensures that it has the latest
system information for proper operation; otherwise, the MS does not transmit in the listening
window until the system information is updated. A sleep cycle is the sum of sleep and listening
windows.


Negative Positive
Traffic Traffic Data Traffic
Indication Indication
W0 W1 W0 W1

SF LW LW LWE LW

F
SW SW SW

W0: Initial Sleep Cycle
Wi: ith Sleep Cycle Sleep Cycle Update:
WL: Final Sleep Cycle For best effort traffic Wi = min(2 * Wi-1, WL)
LW: Listening Window For real-time traffic Wi = W0
LWE: Listening Window Extension
SW: Sleep Window

Sleep Cycle

Listening Window Sleep Window

DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/ DL/
UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL UL

Radio Frame n Radio Frame n+1 Radio Frame n+2 Radio Frame n+3

Micro-sleep Periods


Downlink VoIP/Silence
Downlink HARQ ACK/NACK
Insertion Descriptor (SID) Uplink VoIP/SID transmission
for Uplink transmission
transmission

Uplink HARQ ACK/NACK
Downlink/Uplink allocation
for Downlink transmission

Downlink Uplink Downlink Uplink Downlink Uplink Downlink Uplink

Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms) Sleep Cycle (20 ms)

No Persistent Allocation (Downlink and Uplink VoIP Traffic)



Persistent Allocation (Uplink VoIP Traffic only)



Persistent Allocation (Downlink VoIP Traffic)



Persistent Allocation (Downlink SID Packets)


 IEEE 802.16m facilitates collocated multi-radio operation and coexistence on a mobile platform
through pre-negotiated periodic absence of the IEEE 802.16m MS from the serving BS. The
pattern of such periodic absence is referred to as Collocated Coexistence (CLC) class. The
following CLC class parameters are defined:
◦ CLC Start Time (start time of a CLC class); CLC Active Interval (duration of a CLC class designated for non-
native radio activities); CLC Active Cycle (time interval corresponding to active pattern of a CLC class
repeating); CLC Active Ratio (time ratio of CLC active intervals to CLC active cycle of a CLC class); and
Number of Active CLC Classes (number of active CLC classes of the same type of an MS)
 IEEE 802.16m supports three CLC classes and they differ from each other in terms of the time
unit of CLC start time, active cycle and active interval.
Rescheduled
Initial First First Second
A-MAP A-MAP
Transmission Retransmission Retransmission Retransmission

DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL

CLC Active Interval
Subframe (No Transmission)

Radio Frame k Radio Frame k+1 Radio Frame k+2 Radio Frame k+3

Rescheduling Synchronous HARQ Retransmissions to Avoid CLC Active Interval

...
DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL

Subframe CLC Active Interval CLC Active Interval
(No Transmission) (No Transmission)
Radio Frame k Radio Frame k+1 Radio Frame p Radio Frame p+1

CLC Active Cycle

Type I CLC Class Example


 Idle State provides a power saving mechanism for the MS by allowing the MS to become
periodically available for DL broadcast traffic messaging (e.g., paging message) without
registration at a specific BS.
 The network assigns each Idle Mode MS to a paging group during Idle Mode entry or location
update. This allows the network to minimize the number of location updates performed by the MS
and the paging signaling overhead incurred by the BS.
 The base stations and Idle Mode mobile stations can belong to one or multiple paging groups.
Idle mode mobile stations may be assigned to paging groups of different sizes and shapes based
on user mobility.
 The MS monitors the paging message during mobile station’s paging listening interval. The start
of the mobile station’s paging listening interval is derived based on paging cycle and paging
offset. The paging offset and paging cycle are defined in terms of the number of superframes. The
mobile stations may be divided into logical groups in order to distribute the paging overhead.
 An MS may be assigned to one or more paging groups. If an MS is assigned to multiple paging
groups, it may also be assigned multiple paging offsets within a paging cycle where each paging
offset corresponds to a separate paging group. The MS is not required to perform location update
when it moves within its assigned paging groups. The assignment of multiple paging offsets to an
MS allows monitoring paging message at different paging offset when the MS is located in one of
its paging groups. When an MS is assigned to more than one paging group, one of the paging
groups is called Primary Paging Group and others are known as Secondary Paging Groups. If an
MS is assigned to one paging group, that paging group is considered the Primary Paging Group.


 When different paging offsets are assigned to an MS, the Primary Paging Offset is shorter than
the Secondary Paging Offsets. The distance between two adjacent paging offsets should be long
enough so that the MS paged in the first paging offset can inform the network before the next
paging offset in the same paging cycle so that the network avoids unnecessary paging of the MS
in the next paging offset.
 An Idle State MS (while in paging listening interval) wakes up at its primary paging offset and
looks for primary Paging Group Identifier (PGIDs) information. If the MS does not detect the
primary PGID, it will wake up during its secondary paging offset in the same paging cycle. If the
MS can find neither primary nor secondary PGIDs, it will perform a location update.

Listening Interval

Paging Offset 3 Paging Offset 3

Paging Cycle 1 Paging Cycle 1
Paging Offset 1 Paging Offset 1 Paging Offset 1

Paging Offset 2 Paging Offset 2
Paging Cycle 2

Superframe i Superframe i+1 Superframe i+2

Superframe Superframe Superframe
Boundary Boundary Boundary


 The BS transmits the PGID_Info MAC control message at a predetermined location in the paging
listening interval in order to advertise the paging groups that are supported by the BS or to which
the BS is associated. The PGID_Info is transmitted by the BS regardless of any notifications for
the mobile stations.
 The BS transmits the PGID_Info immediately after the superframe header and advanced MAPs in
the first subframe of the superframe and during mobile station’s paging listening interval.
Superframe = 20 ms

Radio Frame = 5 ms

Transmission bandwidth
Primary Superframe Header

Secondary Superframe Header

Advanced MAPs (Control Channels)

PGID_Info

Secondary Advanced Preamble Subframe


 Persistent Allocation (PA) is a technique to reduce assignment overhead for connections with
periodic traffic pattern and relatively fixed payload size.
◦ To allocate resources persistently to a single connection, the BS transmits separate DL or UL Persistent A-
MAP IEs.
◦ The persistent scheduling does not include any consideration for HARQ retransmission of data packets. The
resources used for retransmissions can be allocated one at a time as needed using a DL or UL Basic
Assign-ment A-MAP IE.
 The Group Resource Allocation (GRA) is a scheduling mechanism that allocates resources to
multiple users as a group in order to reduce the control overhead.
◦ The users are grouped according to the commonality of channel conditions and operational parameters such
as modulation and coding scheme, MIMO mode, HARQ burst size, and resource size. A bitmap is used to
represent different combinations of HARQ burst sizes and resource sizes that are used by a group.
Control Signaling
(Resource Allocation) for Persistent Allocation

... Frame k Frame k+1 Frame k+2 Frame k+3 ...
User Persistent
Allocations
Control Signaling
(Resource Allocation) for Dynamic Allocation

... Frame k Frame k+1 Frame k+2 Frame k+3 ...
User
Allocations


 Bandwidth Request (BR) is a mechanism that an MS uses to inform the serving BS about need
for UL bandwidth allocation.
 The MS may use a contention-based random access BR indicator and an optional quick access
message on BR channel, a standalone bandwidth request, a piggybacked bandwidth request
carried in an extended header in the MAC PDU, or a bandwidth request using fast feedback
channel.
 Bandwidth requests in standalone and piggybacked schemes are done in form of the number of
bytes needed to carry the MAC PDU excluding the physical layer overhead. The bandwidth
request message from the MS indicates the size of the payload excluding any header, security, or
other MAC PDU overhead that are included during transmission over the air-interface.
 An MS requests UL bandwidth per-connection basis. In addition, the MS may request bandwidth
for multiple connections in piggyback scheme.
 Two mechanisms may be used by a network operator to impose cell access restrictions. The first
mechanism is an indication of cell status and special reservations for control of cell selection and
reselection. The second mechanism, referred to as access class control, prevents selected
classes of users from sending initial access messages for control of emergency calls.
 The serving BS may advertise a minimum access class in the BR channel configuration within a
DL control message.
 When an MS has data to send in the uplink using the contention-based random access bandwidth
request mechanism, it must ensure that the priority of the information access class is higher than
or equal to the minimum access class advertised by BR channel configuration within the DL
control message


 The MS waits until the BR channel configuration within a DL control message advertises an
access class with a priority less than or equal to that requested by the MS.
 When the MS access class is allowed, the MS appropriately sets its internal back off window. The
bandwidth request channel and bandwidth request preambles are used for contention-based
random access. Each BR channel indicates a BR opportunity.
 The 3-step random access based BR procedure is illustrated in Figure 6-25. In step 1, the MS
transmits a BR preamble sequence and a quick access message on a randomly selected
opportunity. The BR-ACK A-MAP IE is sent in the next DL frame if the BS detects at least one BR
preamble sequence in the BR opportunities in the previous frame. In this case, if the BR-ACK A-
MAP IE is not sent in the next DL frame, the MS assumes an implicit NACK and may restart BR
procedure.

MS BS MS BS

1- BR Preamble Sequence and Quick Access Message 1- BR Preamble Sequence and Quick Access Message

BR-ACK A-MAP IE BR-ACK A-MAP IE

2- Grant for UL Transmission 2- Grant for Standalone BR Header

3- Scheduled UL Transmission 3- Standalone BR Header

4- Grant for UL Transmission

5- Scheduled UL Transmission


 The security architecture of IEEE 802.16m consists of the MS, the BS, and the
Authenticator.
 Within the MS and BS, the security functions are classified into two logical
categories: 1) Security management entity and 2) Encryption and integrity.
 The security management entity includes the following functions:
◦ Overall security management
◦ Extensible Authentication Protocol (EAP) encapsulation/de-encapsulation for authentication
◦ PKM control functions through key generation/derivation/distribution, and key state
management
◦ Authentication and Security Association (SA) control
◦ Location privacy
 Encryption and integrity protection
Extensible Authentication Protocol
(Outside the Scope of IEEE 802.16m
Specification)

entity consists of the following
Authorization/Security
functions: Association Control
EAP Encapsulation/De-encapsulation

◦ User data encryption/authentication
◦ Management message authentication
◦
Location Privacy Enhanced Key Management PKM Control
Protection of management message
confidentiality
Standalone Signaling Header User Data and Management Message
Management Message Authentication
Authentication Encryption
Encryption and Authentication Functions


Nominal channel bandwidth (MHz) 5 7 8.75 10 20
Sampling factor 28/25 8/7 8/7 28/25 28/25
Sampling frequency (MHz) 5.6 8 10 11.2 22.4
FFT size 512 1024 1024 1024 2048
Sub-carrier spacing (kHz) 10.94 7.81 9.76 10.94 10.94
Useful symbol time Tu (µs) 91.429 128 102.4 91.429 91.429
Symbol time Ts (µs) 102.857 144 115.2 102.857 102.857
Number of OFDM symbols per 5ms frame 48 34 43 48 48
CP FDD
Idle time (µs) 62.857 104 46.40 62.857 62.857
Tg=1/8 Tu
TDD
TTG + RTG (µs) 165.714 248 161.6 165.714 165.714
Symbol time Ts (µs) 97.143 136 108.8 97.143 97.143
FDD
CP Idle time (µs) 45.71 104 104 45.71 45.71
Tg=1/16 Tu Number of OFDM symbols per 5ms frame 50 35 44 50 50
TDD
TTG + RTG (µs) 142.853 240 212.8 142.853 142.853

Symbol Time Ts (µs) 114.286 160 128 114.286 114.286

CP Number of OFDM symbols per 5ms frame 43 31 39 43 43
FDD
Tg=1/4 Tu Idle time (µs) 85.694 40 8 85.694 85.694
TDD
TTG + RTG (µs) 199.98 200 264 199.98 199.98
IEEE 802.16m uses OFDMA in both uplink and downlink as the multiple access scheme
IEEE 802.16m supports other bandwidths between 5 and 20 MHz than listed by dropping edge tones
from 10 or 20 MHz


CP
  ( N 1) / 2

  ( N 1) / 2 1 Tg Tu

  ( N 1) / 2  2 cos(c t )

Serial to ... Parallel to D/A
QAM Cyclic Prefix

...
Modulator
Parallel IFFT Serial
Insertion
Conversion s (t )
Converter Conversion and Filtering
 ( N  1) / 2  2
 ( N  1) / 2  1
Input QAM
Bits Symbols  ( N  1) / 2 mTu time (m+1)Tu

sm (0), sm (1), sm (2), …,sm(N-1)

sm

One Useful OFDM Symbol

Frequency Domain Time Domain


76
Channel

to IFFT

RF Down-
D/A and RF Up-
Conversion and
Conversion
A/D

L-1 zeros

L-1 zeros

L-1 zeros

CP Insertion Remove CP 0
0

Parallel to Serial Serial to Parallel
Conversion Conversion
... ... from
DFT
NFFT Point FFT NFFT Point IFFT
... ...
Sub-carrier

to IFFT
Sub-carrier
Demapping and
Mapping
Equalization

Processing Block Specific to SC-FDMA
... ...
M Point DFT M Point IDFT

0

0
... ...
Serial-to-Parallel Parallel to Serial

from
DFT
Conversion Conversion

Frequency Division Duplex (FDD)

DL DL F1
Frequency Separation

UL UL F2

Time Division Duplex (TDD)

DL UL DL UL F1

Switching Gaps
Half-Duplex FDD (H-FDD)

DL DL F1

UL UL F2

H-FDD with Complementary User Grouping
DL DL DL DL
(Group A) (Group B) (Group A) (Group B) F1
UL UL UL
UL (Group B)
(Group A) (Group B) (Group A) F2

Radio Frame Radio Frame

Listening to DL Broadcast Channels
(No UL Transmission)


Superframe = 20 ms

SF0 SF1 SF2 SF3

Frame = 5 ms

F0 F1 F2 F3

Subframe

Superframe Headers
S0 S1 S2 S3 S4 S5 S6 S7

OFDM
Symbol
S0
S1
S2
S3
S4
S5


TTG and RTG Gaps
Legacy Frame Control Header, DL/UL MAPs

Legacy Frame Control Header, DL/UL MAPs
Legacy UL Control

Legacy UL Control
Channels

Channels
Legacy UL Zone Legacy UL Zone
Legacy Preamble

Legacy Preamble
Legacy DL Zone

Legacy DL Zone
New DL Zone

New DL Zone

New DL Zone

New DL Zone

New DL Zone

New DL Zone
New UL Zone New UL Zone

Legacy Radio Frame from the Point of View of Legacy BS/MS

DL UL DL UL

New Radio Frame from the Point of View of Legacy BS/MS

DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL

Frame Offset New Frame Duration = 5 ms

Legacy Frame Duration = 5 ms


...

Subchannel = 2 x Clusters
P P P

P
18 Sub-carriers

P P P
P P

P P P

UL-PUSC Tile
Subchannelization
Even-Numbered DL-PUSC Slot
OFDM Symbol
P P Cluster Subchannel Offset
Odd-Numbered
OFDM Symbol
Cluster
Nsym
Symbol
...

DL-PUSC Subchannelization Offset
Number of
Subchannels
Number of
DL/UL Subframe DL/UL Subframe DL/UL Subframe Symbols

Physical/Logical Resource Data Region Parameters in
Blocks in IEEE 802.16m the Legacy System


Distribute Physical Resource Distribute Physical Resource Units to Distribute Sub-carriers to
Units to Frequency Partitions Localized and Distributed Groups Logical Subchannels
S0
Localized S1

Permute
Group S2

FP 1
S3
S4
Distributed Inner S5
Group Permutation S6
S7
S8
Physical Sub-carriers

S9
Outer Permutation

...
Localized
Permute Group
FP 2

Distributed Inner
Group Permutation
Permute

Localized
FP 3

Group

Inter-cell (Semi Static) Intra-cell (Dynamic)


Sub - band Mini- band Frequency CRU/ DRU Sub - carrier
Partitioning Permutation Partitioning Allocation Permutation
CRU(FP0)
0
1
2
3
FP0 20
0 21
PRUSB PRUSB 1
2 DRU(FP0)
PRU 0 0 3
0 1 1 12
2 2 12 28
1 20
2 3 3 28 36
3 8 8 44
9 9 36 13
4 44
5 10 10 13 29
6 11 11
16 16 21
7 29 CRU(FP1)
8 17 17 8
9 18 18 9
10 19 19 FP1
24 24 8 10
11 11
12 25 25 9 16
48 Physical Resource Units

26 26 10

48 Logical Resource Units
13 17
14 27 27 11
32 32 16 18
15 19
16 33 33 17
17 34 34 18
35 35 19 DRU(FP1)
18
19 40 40 37 37
20 41 41 45 45
21 42 42 14 14
22 43 43 22 22
23 4 4
24 5 5 FP2 CRU(FP2)
25 6 6
7 7 24 24
26 25 25
27 26 26
28 PRUMB PPRUMB
27 27
29 12 12 32 32
30 13 20 33 33
31 14 28 34 34
32 15 36 35 35
33 20 44 30
34 21 13 38 DRU(FP2)
35 22 21 46
36 30
23 29 15 38
37 28 37
38 29 45 46
39 FP3 15
30 14 40
40 31 22
41 36 30 41 CRU(FP3)
42 42
37 38 43 40
43 38 46 41
44 39 15 4 42
45 5
44 23 6 43
46 45 31 4
47 46 39 7 5
47 47 23 6
31 7
39
47
DRU(FP3)
23
31
39
47
Multi - cell Procedure


CRU(FP0)
0
1
Sub-band Mini-band Frequency 2
Partitioning Partitioning Partitioning PRUFP0 3
20
21
PRU PRUSB PPRUSB 0
1
2
DRU(FP0)
0 0
1 1 3 12
0
2 2 12 28
1
3 3 20 36
2
8 8 28 44
3
9 9 36 13
4
10 10 44 29
5
11 11 13
6
7 16 16 21 CRU(FP1)
17 17 29
8 8
18 18
9
19 19
PRUFP1 9
10 10
11 24 24 8
11
12 25 25 9
16
13 26 26 10
17
14 27 27 11
18
15 32 32 16
19
16 33 33 17
17 34 34 18 DRU(FP1)
18 35 35 19
19 40 40 37 37
20 41 41 45 45
21 42 42 14 14
22 43 43 22 22
23 4 4
5 5
PRUFP2 CRU(FP2)
24
25 6 6
24 24
26 7 7
25 25
27 26
28
PRUMB PPRUMB 26
27 27
29 12 12 32
32
30 13 20 33
33
31 14 28 34
34
32 15 36 35
35
33 20 44 30
34 21 13 38
DRU(FP2)
35 22 21 46 30
36 23 29 15 38
37 28 37
38 29 45 PRUFP3 46
39 15
30 14
40 40
31 22 CRU(FP3)
41 41
36 30
42 42
37 38 40
43 43
38 46 41
44 4
39 15 42
45 5
44 23 43
46 6
45 31 4
47 7
46 39 5
23
47 47 6
31
Sector-Common Procedure 39 7
47 DRU(FP3)
23
31
39
47

Sector-Specific Procedure


HARQ Feedback Channels i and j

Secondary Fast Feedback Channels

c00 c01 c00 c01 c00 c01
P0 c5 c10 c15 c20 c25
c02 c03 c02 c03 c02 c03
c0 c6 c12 P1 c21 c26

...

...
c10 c11 c10 c11 c10 c11

Frequency
HARQ

Frequency
Mini-Tile c1 P2 c12 c16 c22 c27 Feedback
c12 c13 c12 c13 c12 c13 Mini-Tile
c2 c7 c13 c17 P3 c28

...

...
c20 c21 c20 c21 c20 c21
c3 c8 P4 c18 c23 c29
c22 c23 c22 c23 c22 c23
c4 c9 c14 c19 c24 P5
UL Subframe

UL Subframe
Pilot
Primary Fast Feedback Channels
HARQ Feedback

Index of Distributed LRUs in a Frequency Partition
Channels
c01
c00 c02 c04 c06 c08
0
c01
Fast Feedback c01 c03 c05 c07 c09
1
Channels

...
c11
c10 c12 c14 c16 c18

Frequency
0 Feedback
Mini-Tile
c11
Bandwidth Request c11 c13 c15 c17 c19
1
Channels

...
c21
c20 c22 c24 c26 c28
0
c21
c21 c23 c25 c27 c29
Traffic Channels 1

UL Subframe

UL Subframe
UL Tile

A20 A21 B30 B31 A22 A23 A20 A21 B32 B33 A22 A23 A20 A21 B34 B35 A22 A23


UL Subframe
... ...



Frequency


Tile 1
3 OFDM
Symbols
Tile 2

P P

4 Sub-carriers
Tile 3

Allocation of Legacy Uplink
Transmission Bandwidth
of the Legacy System

Control Channels Tile 4

P P
Tile 5
Transmission Bandwidth of the BS

Slot
Tile 6

New PUSC Tile 1

New PUSC Tile 2
of the New System

6 OFDM Symbols

DRU New PUSC Tile 3 P P

4 Sub-carriers
New PUSC Tile 4

New PUSC Tile 5 P P

New PUSC Tile 6
UL Subframe UL Subframe UL Subframe

Uplink Portion of the TDD Radio Frame


Pattern 1 Transmit FP1 Power
Power FP2 Power FP3 Power



Frequency Partition 1 Frequency Partition 2 Frequency Partition 3 Frequency Partition 4

Reuse-1 Partition Reuse-3 Partitions

Logical Resource Units

Downlink FFR

Pattern 1 gIoT

Pattern 2 gIoT

Pattern 3 gIoT

Frequency Partition 1 Frequency Partition 2 Frequency Partition 3 Frequency Partition 4

Reuse-1 Partition Reuse-3 Partitions

Logical Resource Units

Uplink FFR


Important considerations in design of pilot structures for support of multi-antenna OFDMA systems
include the following:
 Identical pilot pattern for each physical resource block: Pilot spacing in time and frequency must
be in proportion with the resource block size. If the location of the pilot tones within a resource
block is not maintained the same across all resource blocks within the system bandwidth or
alternatively the pilot sub-carriers have different positions within each resource block, the filtering
and interpolation operations during channel estimation becomes excessively complex.
 Pilot density: Proper pilot overhead must be considered as a tradeoff between accurate channel
estimation under various mobility conditions and higher throughput.
 Types of pilots: Pilots are typically classified as common and dedicated. Each MS in the cell can
estimate the channel over entire bandwidth using the common pilots while dedicated pilots in the
MS assigned resource block can be used for channel estimation. In conventional MIMO schemes,
the dedicated pilots are typically adaptively precoded.
 Pilot power boosting: In general, the power of pilot sub-carriers is boosted relative to data sub-
carriers in order to enhance the channel estimation with pilot hopping or shifting. To avoid symbol
to symbol power fluctuation when using pilot boosting, it is desirable to place the pilot sub-carriers
regularly on every symbol or to employ power adjustment for data sub-carriers over a symbol.
 Per antenna power balance: When using multiple transmit antennas, it is important to maintain
balanced power distribution across antennas. For this purpose, if there are two transmit antennas,
each OFDM symbol should contain the same number of pilot tones associated with different
antenna ports.


P1 P1 P1 P1 X X P1 P4 P3 P2
P1 P5 P7 P3
P2 P2 X X P2 P2 P2 P6 P8 P4
18 Contiguous Sub-carriers

P2 P3 P4 P1

P3 P7 P5 P1
P4 P8 P6 P2


P1 P1 P1 P1 X X
P2 P2 X X P2 P2

P5 P1 P3 P7
P6 P2 P4 P8
P4 P1 P2 P3

P1 P1 P1 P1 X X
P2 P2 X X P2 P2

6 OFDM Symbols 6 OFDM Symbols 6 OFDM Symbols 6 OFDM Symbols
P7 P3 P1 P5
P8 P4 P2 P6
Antenna Port 1 Antenna Port 2 Antenna Port 1 Antenna Port 2 P3 P2 P1 P4

Single Data Stream Dual Data Stream 6 OFDM Symbols 6 OFDM Symbols

To overcome the effects of pilot interference among the neighboring sectors or base stations, an interlaced
pilot structure is utilized in the downlink by cyclically shifting the base pilot pattern such that the pilots of
neighboring cells do not overlap.


P1 P1 P1 P1

P2 P2

6 Sub-carriers

P1 P1 P1 P1

P2 P2

6 OFDM Symbols 6 OFDM Symbols
Uplink Tile Pilot Patterns for Single and Dual Data Streams

P1 P1 P1 P2
6 Sub-carriers

P1 P1 P2 P1

6 OFDM Symbols 6 OFDM Symbols
Uplink PUSC Tile Pilot Patterns for Single and Dual Data Streams


 The pilot structures are all of narrowband type; i.e., the reference tones only provide channel
information for a fraction of transmission bandwidth since the pilot sub-carriers are contained in
physical or logical resource blocks.
 Some closed-loop MIMO modes require channel information over the entire transmission
bandwidth. This information can only be provided through non-precoded periodic wideband
signals.
 The MIMO midamble is used for precoding matrix index selection in closed-loop MIMO.
 For open-loop MIMO, midamble can be used to calculate the channel quality indicator. MIMO
midamble is transmitted every radio frame on the second downlink subframe.
 The midamble signal occupies the first OFDM symbol in a DL type-1 or type-2 subframe. For the
type-1 subframe, the remaining 5 consecutive OFDM symbols form a type-3 subframe. For type-2
subframe, the remaining 6 consecutive OFDM symbols form a type-1 subframe.
Primary/Secondary
Preambles
MIMO Midambles Switching Gap

DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL

Structure of the MIMO Midamble in Time

Sub-band 1

Sub-band 2

Sub-band n
Antenna Antenna Antenna Antenna Null
Port 1 Port 2 Port 3 Port 4 Sub-carrier

Structure of the MIMO Midamble in Frequency


Systematic Bits
Input Bits XS Output Bits
YS
Parallel to Serial
Converter
Parity Bits XP1

Constituent
Convolutional
Encoder 1

Puncturing
Constituent
Turbo Interleaver Convolutional
Encoder 2

Interleaved
Interleaved Bits Parity Bits XP2

Turbo Encoder Structure
Output Bits

Decision

De-interleaver

Interleaver
Parity Bits XP1 Decoder 1 Decoder 2

Systematic Bits
XS

Interleaver

Interleaved
Parity Bits XP2

Iterative Turbo Decoder Structure

Convolutional Turbo Coder is used in IEEE 802.16m


 Convolutional Turbo Code (CTC) with code rate 1/3
◦ FEC block sizes ranging from 48 to 4800
◦ Bit grouping: solve the 64QAM degradation problem
◦ FEC CRC and burst CRC
 Burst size signaling
◦ A small set of burst sizes and simple concatenation rule
◦ Rate matching (continuous code rate)
 Control channels (DL: SFH and A-A-MAP; UL: SFBCH and BW-REQ) FEC is based
on TBCC
• Minimal code rate is 1/4 for DL and 1/5 for UL
• Random puncturing with sub-block interleaver and rate-matching
 HARQ coding
◦ HARQ-IR (4 SPID defined for DL, signaled in A-MAP)
◦ CoRe (Two versions for 16QAM and 64QAM, DL CoRe version signaled in A-MAP, UL CoRe
version changes when using circular buffer wrap around)

Bit
FEC Block FEC
Burst CRC Burst Randomizing Selection
Function CRC Encoder Collection Modulation
Addition Partition and
Addition (CTC)
Repitition


BURST BURST BURST
INDEX SIZE # OF FEC BLOCKS INDEX SIZE # OF FEC BLOCKS INDEX SIZE # OF FEC BLOCKS
(BYTE) (BYTE) (BYTE)

1 6 1 23 90 1 45 1200 2

2 8 1 24 100 1 46 1416 3

3 9 1 25 114 1 47 1584 3

4 10 1 26 128 1 48 1800 3

5 11 1 27 145 1 49 1888 4

6 12 1 28 164 1 50 2112 4

7 13 1 29 181 1 51 2400 4

8 15 1 30 205 1 52 2640 5

9 17 1 31 233 1 53 3000 5

10 19 1 32 262 1 54 3600 6

11 22 1 33 291 1 55 4200 7

12 25 1 34 328 1 56 4800 8

13 27 1 35 368 1 57 5400 9

14 31 1 36 416 1 58 6000 10

15 36 1 37 472 1 59 6600 11

16 40 1 38 528 1 60 7200 12

17 44 1 39 600 1 61 7800 13

18 50 1 40 656 2 62 8400 14

19 57 1 41 736 2 63 9600 16

20 64 1 42 832 2 64 10800 18

21 71 1 43 944 2 65 12000 20

22 80 1 44 1056 2 66 14400 24


Channels Descriptions
PA-Preamble Enable Timing/Carrier acquisition common to all BS’s.
Preamble
SA-Preamble 256x3=768 preamble indices for Cell ID

MIMO channel estimation, CQI and PMI estimation
MIMO Midamble
Low PAPR Golay sequence, and Reuse 3

Primary Super Frame Header
Essential system parameters and system configuration information.
SFH
Secondary Super Frame Header Located in the first DL subframe of a superframe
DL

Contain the information such as resource allocation/HARQ/MIMO
Assignment A-MAP
Presents in every DL subframe
A-MAP
Non-User Specific A-MAP Contain the resource allocation for Assignment A-MAP
HARQ Feedback A-MAP UL HARQ ACK/NACK
Power Control A-MAP Power control information
Primary Fast Feedback CQI & MIMO Rank
UL Feedback
Secondary Fast Feedback PMI & Band Selection
Channel
UL HARQ Feedback Channel DL HARQ ACK/NACK
UL Ranging Non-Synchronized AMSs Initial Entry and Handover
Channel Synchronized AMSs Periodic uplink time synchronization
BW REQ Channel 3-Step fast & 5-Step robust uplink bandwidth request
Sounding Channel UL Channel Sounding

94 Sassan Ahmadi/IEEE GLOBECOM 2010/December 2010

Frequency
System Bandwidth

Subframe

FDD
Duplex DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL DL
Mode

TDD
Duplex DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL
Mode

Radio Frame

Superframe

Superframe Primary Advanced Secondary Advanced FDD Idle Time/
Headers Preamble Preamble TDD Switching Gaps

Legacy Preamble PA-Preamble SA-Preamble
20 ms Superframe
5 ms Legacy Radio Frame 5 ms New Radio Frame 5 ms New Radio Frame
DC

EFGH ABCD EFGH ABCD EFGH ABCD EFGH ABCD

FrameOFFSET
Frequency
512-Point FFT

PA-Preamble and Legacy 1024-Point FFT
Preamble Occupy Uncorrelated
... ...
Locations in Frequency Domain 2048-Point FFT

Frequency Frequency

Sub-carrier Assignment in PA-Preamble Sub-carrier Assignment in Legacy Preamble


6 OFDM Symbols

P-SFH NP-SFH
NSFH
Distributed

Logical
Resource
S-SFH NS-SFH Units
SA-Preamble

NPRU

Data and Control
Blocks

Time
20 ms
40 ms
80 ms
160 ms P-SFH S-SFH SP2 S-SFH SP3 S=SFH SP1


SFH IE Type Content

LSB of Superframe number, S-SFH change count, S-SFH Size, S-SFH Number of
P-SFH IE
Repetitions, S-SFH Scheduling information bitmap, S-SFH SP change bitmap
Start superframe offset, MSB of superframe number, LSB of 48 bit ABS MAC ID, Number
of UL ACK/NACK channels, Number of UL ACK/NACK channels, Power control channel
resource size, Non-user specific A-MAP location, A-A-MAPMCS selection, DL
S-SFH SP1
permutation configuration, UL permutation configuration, Unsync ranging allocation
interval channel information, Unsync ranging location in the frame, RNG codes
information, Ranging code subset/ partition, ABS EIRP, Cell bar information
Start superframe offset, Frame configuration index, UL carrier frequency, UL bandwidth,
MSB bytes of 48 bit ABS MAC ID, MAC protocol revision, FFR partitioning info for DL
S-SFH SP2
region, FFR partitioning info for UL region, AMS Transmit Power Limitation Level,
EIRPIR_min
Start superframe offset, Rate of change of SP, SA-sequence soft partitioning, FFR
partition resource metrics, N1 information for UL power control, UL Fast FB Size, # Tx
antenna, SP scheduling periodicity, HO Ranging backoff start, HO Ranging backoff end,
S-SFH SP3 Initial ranging backoff start, Initial ranging backoff end, UL BW REQ channel information,
Bandwidth request backoff start, Bandwidth request backoff end, Uplink AAI subframe
bitmap for sounding, Sounding multiplexing type (SMT) for sounding, Decimation value D/
Max Cyclic Shift Index P for sounding


HARQ Feedback A-MAPs
Power Control A-MAPs
Non-User-Specific A-MAPs

Assignment A-MAPs

...
Guardbands
A-MAP A-MAP A-MAP A-MAP A-MAP UL-Control UL-Control
A-MAP Region
Region Region Region Region Region Region Region

MIMO Midamble
SA-Preamble

PA-Preamble
RTG
TTG
SFH

DL Bursts UL Bursts
DL Bursts
DL Bursts UL Bursts
DL Bursts UL Bursts

Guardbands

DL DL DL DL DL UL UL UL DL
Radio Frame = 5 ms

P-SFH Subframe
PFBCH/SFBCH

HARQ
S-SFH Feedback
SP1/SP2/SP3
BW-REQ


H-ARQ Feedback A-MAP
Power Control A-MAP
Non-User Specific A-MAP
Assignment A-MAP

NA-MAP
A-MAP Region

...
Distributed Resource

Primary Frequency Partition
Units Partition
Assignment A-MAP

Nsym

Localized Resource
Units Partition

DL/UL Subframes

A-MAP A-MAP A-MAP A-MAP A-MAP
UL UL UL UL
DL DL DL DL DL
A-MAP Region Location in TDD Mode with 4:4 DL:UL Ratio

Radio Frame = 5 ms


Assignment A-MAP IE Type Usage
Allocation information for AMS to decode DL bursts using continuous logical
DL Basic Assignment
resources
Allocation information for AMS to transmit UL bursts using continuous logical
UL Basic Assignment
resources
Allocation information for AMS to decode DL bursts using sub-band based
DL Sub-band Assignment
resources
Allocation information for AMS to transmit UL bursts using sub-band based
UL Sub-band Assignment
resources
Feedback Allocation Allocation or deallocation of UL fast feedback control channels to an AMS
UL Sounding Command Control information for AMS to start UL sounding transmission
Allocation for AMS requesting bandwidth using a ranging or bandwidth
CDMA Allocation
request codes
DL Persistent DL persistent resource allocation
UL Persistent UL persistent resource allocation
Group Resource Allocation Group scheduling and resource allocation
Allocation for AMS to send MIMO feedback using MAC messages or
Feedback Polling
extended headers
Indication of decoding status of bandwidth request opportunities
BR-ACK
and resource allocation of bandwidth request header
Broadcast Broadcast burst allocation and other broadcast information


Non-user
Non-user Specific Channel Code QPSK SFBC
Specific
A-MAP Coding Repetition Modulator Encoder
A-MAP Symbols

Physical Processing of Non-user Specific A-MAP Information Elements

Assignment
Assignment Data CRC Channel Code QPSK SFBC
A-MAP
A-MAP-IE Scrambler Insertion Coding Repetition Modulator Encoder
Symbols

Physical Processing of Assignment A-MAP Information Elements

HARQ Feedback Code STID
A-MAP-IE Repetition Scramble
I/Q
Multiplexing
SFBC
HARQ Feedback
Encoder/
A-MAP Symbols
Precoder
I/Q
Multiplexing

Physical Processing of HARQ Feedback A-MAP Information Elements

MSB I Code
ith Power Control QPSK
LSB Q Repetition
A-MAP IE Modulator
(x2) SFBC
Power Control
Encoder/
A-MAP Symbols
(i+1)th Power MSB I Code Precoder
QPSK
Control LSB Q Repetition
Modulator
A-MAP IE (x2)

Physical Processing of Power Control A-MAP Information Elements


HARQ Feedback A-MAP
A-MAP Region

Power Control A-MAP
Non-User Specific A-MAP Broadcast Assignment A-MAP IE
Assignment A-MAP 1
Assignment A-MAP 2

...
Assignment A-MAP N

...

AAI_TRF-IND
AAI_PAG-IND All data traffic and management messages are composed of a AGMH
and a payload
AAI_NBR-ADV
AGMH Payload
...

AAI_TRF-IND
Data Burst 1

Data Burst 2 FRMT Parameters for AAI_TRF- IND

FRMT: This parameter indicates the type of Traffic Indication in AAI_TRF-
IND control message (SLPID bitmap-based or SLPID-based traffic indication)


Frame # 4i 4i+1 4i+2 4i+3 4i+4 4i+5 4i+6 4i+7 4i+8 4i+9 4i+10 4i+11

CQI Report A #
CQI Report B # Bi Ai+1 Bi+1 Ai+2 Bi+2 Ai+3
CQI for Reuse 1

CQI for Reuse 3
Short-term Long-term Report B Punctures Short-term Allocation Period (p=1)
Report = 2 Short-term Report A at every 4th Long-term Allocation Period (q=0)
Frames Frame Number of Reports (n=2)

Frame # 8i 8i+1 8i+2 8i+3 8i+4 8i+5 8i+6 8i+7 8i+8 8i+9 8i+10 8i+11 8i+12 8i+13 8i+14 8i+15

CQI Report A #
CQI Report B # Bi Ai+1 Ai+2 Ai+3 Bi+1 Ai+5 Ai+6 Ai+7
Short-term
Report = 2
CQI for MIMO Mode
Frames Note: Ai+4 = Ai+3
SM (Rank 2)
Long-term Report B Punctures Short-term Short-term Allocation Period (p=1)
CQI for MIMO Mode Report A at every 8th Frame Long-term Allocation Period (q=1)
SFBC Number of Reports (n=2)


 The sounding channel is used by a mobile
station to send sounding signals for MIMO
feedback, channel quality feedback, and uplink

Wideband Sounding Channel
channel measurement at the base station.

Data/Control Channels


 Uplink sounding enables sounding-based
downlink MIMO in TDD mode and uplink
closed-loop MIMO in TDD and FDD modes.
 The sounding channel occupies specific uplink
sub-bands (narrowband sounding signal) or the
entire bandwidth (wideband sounding signal) DL DL DL DL DL UL UL UL

over one OFDM symbol TDD Radio Frame = 5 ms

 The sounding signal is transmitted over
predefined sub-carriers within the sub-bands.



The sounding channel parameters are
transmitted in System Configuration Descriptor
MAC control message and SFH SP1 broadcast
channel.
 The periodicity of the sounding signal for each
MS is configurable. The sounding channel is DL DL DL DL DL UL UL UL
frequency-division multiplexed (narrowband TDD Radio Frame = 5 ms

sounding) or time-division multiplexed Narrowband Sub-band based Sounding

(wideband sounding) with other control and
data channels.


Copy Samples

Non-Synchronized Initial
Ranging Format 0
RCP RP RP
Gap
TRanging CP TRP TRP
Uplink Subframe
Copy Samples

Non-Synchronized Initial
Ranging Format 1 RCP RP
Gap

TRanging CP TRP
Uplink Subframe

Synchronized
CP CP CP CP CP CP
Ranging

Tg Tu
3 OFDM Symbols = 1 Basic Unit 3 OFDM Symbols = 1 Repeated Basic Unit
6 OFDM Symbols = 1 Uplink Subframe

Copy Samples Copy Samples

Legacy Non-
Synchronized Initial CP CP
Ranging
Tg Tu Tu Tg
Copy Copy Copy Copy
Samples Samples Samples Samples
Initial and Periodic
Ranging Channels in
CP CP CP CP CP CP
FDM-based UL-PUSC
Zone
Tg Tu Tu Tg Tg Tu Tu Tg Tg Tu Tg Tu
Periodic Ranging
Initial Ranging Channel Initial Ranging Channel
Channel
(Non-synchronized MS) (Non-synchronized MS)
(Synchronized MS)
6 OFDM Symbols = 1 Uplink Subframe

Format TRCP TRP ∆fRP Physical Resource Maximum Coverage

144 Sub-carriers  3
IEEE Std 802.16-2009 - - ∆f 12 km
OFDM Symbols

IEEE 802.16m 1 Sub-band  1
3.5Tg + Tu 2Tu ∆f /2 18 km
Format 0 Subframe

IEEE 802.16m 1 Sub-band  3
3.5Tg + 7Tu 8Tu ∆f /8 100 km
Format 1 Subframe


Single-BS MIMO
Modes

Closed-loop Closed-loop Open-loop Open-loop Closed-loop Closed-loop Open-loop
SU-MIMO MU-MIMO SU-MIMO MU-MIMO SU-MIMO MU-MIMO SU-MIMO

Localized Resource Allocations Distributed Resource Allocations

Multi-BS MIMO
Modes

Closed-loop
PMI Restriction PMI Recommendation Collaborative MIMO
Macro Diversity

Single-BS with PMI Coordination Multi-BS Precoding with Coordination


MIMO Mode Selection

Precoder Vector/Matrix Selection

User 1
Encoder
Data
IFFT

User 2
Data Encoder Sub-
IFFT
carrier

...

...
...
Resource MIMO
...
...

Scheduler Precoder and

...
Mapping Encoder
... Antenna

...
...
Mapping IFFT
User N-1
Data
Encoder
User N IFFT
Data

Feedback
CQI, CSI, ACK/NACK
Mode/ Rank/ Link Adaptation Layers Streams Antenna Ports

Mini-Band based CRU Sub-Band based CRU
DRU
Mode Index Description MIMO Encoding Format MIMO Precoding Permutation Support Permutation Support
Permutation Support
(Diversity Allocation) (Localized Allocation)

Mode 0 Open-Loop SU-MIMO SFBC Non-Adaptive Yes Yes Yes

Open-Loop SU-MIMO
Mode 1 Vertical Encoding Non-Adaptive Yes Yes Yes
(Spatial Multiplexing)

Closed-Loop SU-MIMO
Mode 2 Vertical Encoding Adaptive No Yes Yes

Open-Loop MU-MIMO
Mode 3 Horizontal Encoding Non-Adaptive No No Yes

Closed-Loop MU-MIMO
Mode 4 Horizontal Encoding Adaptive No Yes Yes

Open-Loop SU-MIMO Conjugate Data
Mode 5 Non-Adaptive No No No
(Transmit Diversity) Repetition


MIMO Mode Selection

Precoder Vector/Matrix Selection

Resource Allocation
MCS/Packet Size
ACK/NACK IFFT
Mode/ Rank/PMI

Sub-
IFFT
carrier

...

...
Encoder

...
User Resource MIMO
Precoder and

...
Data Mapping Encoder
Antenna
Mapping IFFT

IFFT

Layers Streams Antenna Ports

Mode Index Description MIMO Encoding Format MIMO Precoding

Mode 0 Open-Loop SU-MIMO SFBC Non-Adaptive

Open-Loop SU-MIMO
Mode 1 Vertical Encoding Non-Adaptive

Closed-Loop SU-MIMO
Mode 2 Vertical Encoding Adaptive

Open-Loop Collaborative
Mode 3 Spatial Multiplexing (MU- Vertical Encoding Non-Adaptive
MIMO)

Closed-Loop Collaborative
Mode 4 Spatial Multiplexing (MU- Vertical Encoding Adaptive
MIMO)


Long-term FB Short-term FB Event-driven FB

STC_Rate (indicates the preferred Narrow band CQI for best-M Preferred MIMO feedback
number of MIMO streams for SM; mode
e.g., STC Rate 1 means SFBC with Sub-band Index for best-M
precoding)

Short-term PMI for
CL SU/MU MIMO
Sub-band Index for best-M

Correlation Matrix R for Stream Index for OL MU MIMO
Transform CB and long-term BF

Wideband CQI

Long-term PMI


Downlink Coherent Combining or Dynamic Cell Selection
(Joint Transmission/Dynamic Cell Selection)

Downlink Coordinated Scheduling/Beamforming

n
a tio
r din
C oo
ell

ce
-c

rfa
tra n
In

nte
tio
ina

SI
d
or

r-B
o
ll C

e
Uplink Coordinated Multi-point Reception

Int
e
(Receiver signal processing at central BS) r-C
te
In


 There are two ways to support legacy systems in IEEE 802.16m
◦ TDM of the DL zones and FDM of the UL zones (when UL PUSC is used in legacy UL)
◦ TDM of the DL zones and TDM of the UL zones (when AMC is used in legacy UL)
 The UL link budget limitations of the legacy are considered in both UL approaches by
allowing the legacy allocations to use the entire UL partition across time.
 The synchronization, broadcast, and control structure of the two systems are mainly
separated and these overhead channels present irrespective of the relative load of
the network (i.e., the percentage of legacy and new terminals in the network).
 In TDD duplex scheme, the frame partitioning between DL and UL and the switching
points are synchronized across the network to minimize inter-cell interference.
 The frame partitioning in IEEE 802.16m (superframe/frame/subframe) is transparent
to the legacy BS and MS.
 The new BS or MS can fall back to the legacy mode when operating with a legacy
MS or BS, respectively.
 While a number of upper MAC functions and protocols may be shared between
legacy and new systems, most of the lower MAC and PHY functions and protocols
are different or differently implemented (a dual-mode operation for support of legacy).
The legacy and new systems can simultaneously operate on the same RF carrier by
dynamically sharing in time and/or frequency the radio resources over the frame.


In order to improve the throughput of both IEEE 802.16m and the legacy systems in the mixed-mode
operation, the frame structure for the legacy support was modified.

Current Frame Configuration (2 wasted symbols, 4 symbol legacy zone, 21 symbol new zone)

System Bandwidth
Legacy Zone
LEGACY PREAMBLE

NEW PREAMBLE

NEW MIDAMBLE
Legacy Zone
NOT USED

TTG
New Zone

DL Subframe DL Subframe DL Subframe DL Subframe DL Subframe
4 Usable 5 Usable 5 Usable 6 Usable 5 Usable
6 OFDM Symbols 6 OFDM Symbols 6 OFDM Symbols
OFDM Symbols OFDM Symbols OFDM Symbols OFDM Symbols OFDM Symbols

6 SYMBOL 6 SYMBOL 6 SYMBOL 6 SYMBOL 5 SYMBOL
SUBFRAME SUBFRAME SUBFRAME SUBFRAME SUBFRAME

Modified Frame Configuration (0 wasted symbols, 4 symbol legacy zone, 23 symbol new zone)

System Bandwidth
Legacy Zone
LEGACY PREAMBLE

NEW PREAMBLE

NEW MIDAMBLE

Legacy Zone

TTG
New Zone

DL Subframe DL Subframe DL Subframe DL Subframe DL Subframe
4 Usable 5 Usable 5 Usable 6 Usable 6 Usable
6 Usable OFDM Symbols 6 Usable OFDM Symbols 6 Usable OFDM Symbols
OFDM Symbols OFDM Symbols OFDM Symbols OFDM Symbols OFDM Symbols

5 SYMBOL 6 SYMBOL 6 SYMBOL 6 SYMBOL 6 SYMBOL
SUBFRAME SUBFRAME SUBFRAME SUBFRAME SUBFRAME


ble e
am am
re Fr er
yP ing io
ac itc
h ad ead
R H
g g
Le Sw p hin cy o l
L
/U Ga itc ga ntr
AP L Sw Le Co
D L ap
Legacy Uplink Control Channels


M
L- AP L/
D G A-MAP Region A-MAP Region
y D L- M


c U A-MAP Region
ga y U A-MAP Region A-MAP Region
Le gac
Le y
ar
nd Legacy Legacy Legacy
co l e ar
y
Se mb im Legacy Legacy
w a Uplink Pr ble Uplink Uplink

Ne Pre ew eam Uplink Uplink
Zone N r Zone Zone
Legacy Downlink Zone




P
Zone Zone
New Downlink Zone

New Downlink Zone
New Downlink Zone

New Downlink Zone

New Downlink Zone
Superframe Headers

Superframe Headers
New Uplink New Uplink New Uplink
Control Control Control
Channels Channels New Uplink Channels New Uplink
Control Control
Channels Channels

New Uplink New Uplink
New Uplink New Uplink
Zone Zone
Zone Zone
New Uplink
Zone

DL Subframe UL Subframe DL Subframe UL Subframe DL Subframe UL Subframe DL Subframe UL Subframe DL Subframe UL Subframe
Legacy Radio Frame 5 ms Legacy DL Subframe

DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL DL DL DL UL UL UL DL DL
New Frame 5 ms New DL Subframe
Superframe 20 ms

Hypothetical distribution of time-frequency resources between the legacy and the new systems




Urban Urban
Simulation Parameters Indoor Hotspot (InH) Rural Macro-cellular (RMa)
Micro-cellular (UMi) Macro-cellular (UMa)
Baseline Parameters
Base station Antenna Height 6 10 25 35
(m) (On the Ceiling) (Below Rooftop) (Above Rooftop) (Above Rooftop)
Number of BS Antennas
Up to 8/Up to 8 Up to 8/Up to 8 Up to 8/Up to 8 Up to 8/Up to 8
(Receive/Transmit)
Base Station Transmit Power 24 (40 MHz) 41 (10 MHz) 46 (10 MHz) 46 (10 MHz)
(dBm) 21(20 MHz) 44 (20 MHz) 49 dBm (20 MHz) 49 (20 MHz)
Mobile Station Transmit Power
21 24 24 24
(dBm)
Number of MS Antennas
(Receive/Transmit)
Minimum Distance between
3 10 25 35
MS and BS (m)
RF Carrier Frequency (GHz) 3.4 2.5 2 0.8
Outdoor to Indoor Penetration
N/A See Annex 1, Table A1-2 of [6] N/A N/A
Loss
Outdoor to In-Car Penetration 9 dB 9 dB
N/A N/A
Loss (Log-Normal, σ = 5 dB) (Log-Normal, σ = 5 dB)
Parameters for Analytical Assessment of Peak Spectral Efficiency
Number of BS Antennas
(Receive/Transmit)
Number of MS Antennas
(Receive/Transmit)
Parameters for System-Level Simulations
Network Layout Indoor Floor Hexagonal Grid Hexagonal Grid Hexagonal Grid
Inter-Site Distance (m) 60 200 500 1732
Urban Micro-cellular Channel Urban Macro-cellular Channel Rural Macro-cellular Channel
Channel Model Indoor Hotspot Channel Model
Model Model Model
Randomly and uniformly Randomly and uniformly
Randomly and uniformly
Randomly and uniformly distributed over area distributed over area
User Distribution distributed over area
distributed over area 50% pedestrian users and 100% high speed vehicular
100% vehicular users
50% users indoor users


Urban Urban
Simulation Parameters Indoor Hotspot (InH) Rural Macro-cellular (RMa)
Micro-cellular (UMi) Macro-cellular (UMa)

All mobile stations have fixed All mobile stations have fixed All mobile stations have fixed All mobile stations have fixed
and identical speed with and identical speed with and identical speed with and identical speed with
User Mobility
randomly and uniformly randomly and uniformly randomly and uniformly randomly and uniformly
distributed direction distributed direction distributed direction distributed direction
MS Speed (km/h) 3 3 30 120
Inter-Site Interference Explicitly Modeled Explicitly Modeled Explicitly Modeled Explicitly Modeled
BS Noise Figure (dB) 5 5 5 5
MS Noise Figure (dB) 7 7 7 7
BS Antenna Gain (Bore-Sight)
0 17 17 17
(dBi)
MS Antenna Gain (dBi) 0 0 0 0
Thermal Noise Level (dBm/Hz) –174 –174 –174 –174
Parameters for Assessment of Cell Spectral Efficiency and Cell Edge User Spectral Efficiency
Traffic Model Full Buffer Full Buffer Full Buffer Full Buffer
220 MHz (FDD) 210 MHz (FDD) 210 MHz (FDD) 210 MHz (FDD)
System Bandwidth
40 MHz (TDD) 20 MHz (TDD) 20 MHz (TDD) 20 MHz (TDD)
Number of Users/Cell 10 10 10 10
Parameters for Evaluation of VoIP Capacity
Traffic Model VoIP VoIP VoIP VoIP
25 MHz (FDD) 25 MHz (FDD) 25 MHz (FDD) 25 MHz (FDD)
System Bandwidth
10 MHz (TDD) 10 MHz (TDD) 10 MHz (TDD) 10 MHz (TDD)
Simulation Duration for a
20 20 20 20
Single Drop (s)
Parameters for Link-Level Simulation (Mobility Requirement)
Traffic Model Full buffer Full buffer Full buffer Full buffer
Urban Micro-cellular Channel Urban Macro-cellular Channel Rural Macro-cellular Channel
Channel Model Indoor Hotspot Channel Model
Model Model Model
System Bandwidth (MHz) 10 10 10 10
Number of Users/Cell 1 1 1 1


Test Environments
Requirements Duplex Scheme DL/UL
InH UMi UMa RMa
Cell spectral efficiency (bit/s/Hz/cell) 6.93 3.22 2.41 3.23
ITU-R requirement 3.0 2.6 2.2 1.1
TDD
Cell edge user spectral efficiency (bit/s/Hz/cell) 0.260 0.092 0.069 0.093
DL
FDD
TDD
UL
FDD
VoIP Capacity (Users/Sector/MHz) 140 82 74 89
TDD
ITU Requirement 50 40 40 30
DL/UL
VoIP Capacity (Users/Sector/MHz) 139 77 72 90
FDD
ITU Requirement 50 40 40 30


Core Documents
1.P802.16m Project Authorization (PAR)
2.P802.16m Five Criteria
3.IEEE 802.16m Work Plan
4.IEEE 802.16m System Requirements Document (SRD)
5.IEEE 802.16m System Description Document (SDD)
6.IEEE 802.16m Evaluation Methodology Document (EMD)
7.IEEE 802.16m Amendment Working Document (AWD)
8.System Evaluation Details for IEEE 802.16 IMT-Advanced Proposal (SED)
9.Candidate IMT-Advanced RIT based on IEEE 802.16 (IEEE Contribution to ITU-R Working Party
5D)
10.Style Guide for 802.16m Amendment Contributions
11.IEEE 802.16m Internal Documents Configuration Control Procedure (CCP)
Additional Resources
1. IEEE 802.16 IMT-Advanced Candidate Proposal Page http://ieee802.org/16/imt-adv/index.html
2. ITU-R (IMT-Advanced submission and evaluation process) http://www.itu.int/ITU-
R/index.asp?category=study-groups&rlink=rsg5-imt-advanced&lang=en
3. IEEE P802.16m/D9 Draft Standard


An Overview of IEEE 802.16m Radio Access Technology Globecom 2010

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