LTE-Training-With Basic Parameters and tecgnology

For internal use only
1 © Nokia Siemens Networks
Long Term Evolution (LTE)
Helsinki
12th May, 2009
Harri Holma, Antti Toskala
Nokia Siemens Networks

Outline
• Background of LTE
• 3GPP Status & LTE Schedule
• LTE Physical Layer
• LTE Layer 2/3
• LTE Architecture
• LTE UE Connection management
• LTE Network Algorithms
• LTE Network Performance
• LTE Frequency variants
• LTE Benchmarking with HSPA+
• LTE Advanced
Reference material:

Background of LTE
• End 2004 3GPP workshop on UTRAN Long Term Evolution
• March 2005 Study item started
• December 2005 Multiple access selected
• March 2006 Functionality split between radio and core agreed
• September 2006 Study item closed & approval of the work items
• December 2007 1st version of all radio specs approved for Release 8
• March 2009 Backwards compatibility (ASN.1) started
2005 2006 2007 2008
Feasibility
study
started
Multiple
access
selected
Feasibility
study closed
Work item
started
Work plan
approved
Stage 2
approved
Stage 3
approved
ASN.1
frozen!
2009

LTE Status in 3GPP
• LTE functional freeze has been reached, so no new
functionality to be introduced anymore in Release 8
• RRC (Radio Resource Control) specification is the biggest
open issue in LTE specifications
• NSN/Nokia and Vodafone introduced an action plan in
3GPP in September to ensure things are completed.
Different companies took responsibility of different areas
• For December 2008 version most of the open issues also in
LTE RRC were solved, target freezing date for ASN.1 for
March 2009 was reached.
– Any commercial devices thus needs to be build on top of the March
2009 RRC specification (Freeze also for X2/S1 specs)
– First feedback from 1st round of meetings did not reveal major
problems (that could not be solved with backwards compatible CRs)

LTE Timing in 3GPP
• LTE started backwards compatibility March 2009
• Historically, it has taken 1.25-1.5 years from the backwards compatibility
until commercial launch with HSDPA and HSUPA
– Note that then the basis was existing and stable Release 99
• LTE commercial launch expected 2H/2010
2003 2004 2005 2006 2007
1 2
1 2
1.5 years
1.25 years
1 = Backward compatibility
2 = 1st commercial launch
HSDPA
HSUPA
2008 2009 2010
1 2
1.5 years
LTE

General Requirements for UTRAN Evolution
Feasibility study started in 3GPP for UTRAN Long Term Evolution with the
following requirements
• Packet switched domain optimized
• One way (radio) delay below 5 ms
• Peak rates uplink/downlink 50/100 Mbps
• Ensure good level of mobility and security
• Improve terminal power efficiency
• Frequency allocation flexibility with 1.25/2.5, 5, 10, 15 and 20 MHz
allocations, possibility to deploy adjacent to WCDMA*
• WCDMA evolution work on-going to continue with full speed
Operators are also requiring higher radio capacity
• Depending on the case 3-4 times higher capacity expected than
with Release 6 HSDPA/HSUPA reference case
* For small bandwidths 1.4 and 3.0 MHz adopted instead

Multiple Access Selection
Due to the large bandwidth, up to 20 MHz, and up to 100 Mbps data rates ->
something more than just a new modulation or larger chip rate was needed
3GPP decided in the feasibility study to use as multiple access OFDMA
(Downlink) and SC-FDMA (Uplink)
3GPP considered several alternatives
• OFDMA
• SC-FDMA
• And use of Multi-carrier WCDMA
• For the downlink the choice was clear, while for the uplink a bit more
debate too place between OFDMA and SC-FDMA as especially
companies with WiMAX background preferred similarity with WiMAX.
– SC-FDMA was also our preference (see later slides on PAR issues)
– The chosen multiple access methods will be driven with reuse 1 like in WCDMA

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RAN1#54bis
RAN1#54
RAN1#53bis
RAN1#53
RAN1#52b
RAN1#52
RAN1#51bis
Nokia/NSN Most Active in 3GPP LTE Work
• Nokia/NSN most active contributor in 3GPP RAN1 for LTE
Nokia/NSN
most active

OFDMA in LTE Downlink

OFDM benefits
Superior performance in frequency selective fading channels
Complexity of base-band receiver is much lower
Good spectral properties and handling of multiple bandwidths
Link adaptation and frequency domain scheduling
offer high potential for throughput etc gain
Other cell interference can be effectively reduced by
Interference Rejection Combining (IRC).

FFT – a fundamental element in OFDM
FFT = Fast Fourier Transform, IFFT = Inverse FFT
FFT/IFFT allows to move between time and frequency domain representation and is
a defacto block in an OFDMA system where system parameters enable that
As an example a sinusoidal wave input and “block wave” input for an FFT block
Time Domain
FFT
Frequency Domain
FFT
f
f
This corresponds to the frequency
Of the input sinusoidal wave
t
Fundamental frequency

Bandwidth Scalability
1.4 MHz
3.0 MHz
5 MHz
10 MHz
20 MHz
FFT size
128
256
512
1024
2048
Bandwidth
Scalable bandwidth 1.4 – 20 MHz using different number of sub-carriers and
different FFT size
Large bandwidth provides high data rates
Small bandwidth allows simpler spectrum re-farming, e.g. 450 MHz and 900 MHz
Narrow spectrum refarming
High data rates

DL air interface technology
OFDM-based DL air interface
Frequency bandwidth options are 1.4
MHz, 3.0 MHz, 5 MHz, 10 MHz, 15 MHz
and 20 MHz
Each BW has fundamentally similar
features
• Symbols are parameterized equally
• 15 kHz subcarrier spacing
• Clock is 2N (8x) multiple of 3.84 MHz
• FFT scales as a power of two
3GPP is discussion also alternative
parameters for the broadcast use
(Mobile TV case
Up to 20 MHz

OFDM Transmitter/Receiver Chain
OFDM is used in various
systems, like:
• DVB-T
• DVB-H
• WLAN (IEEE family)
– Including WiMax
• Key component is the
inverse discrete Fourier
transform
• IDFT/IFFT
• Moving between time and
frequency domain
representation
frequency
Transmitter
totalradio BW (
eg. 20 MHz)
Modulator
Cyclic
Extension
Remove
Cyclic
Extension
Equaliser
Bits
frequency
Receiver totalradio BW (
eg. 20 MHz)
Modulator
Bits
IFFT
IFFT
Serial to
Parallel
…
IFFT
Serial to
Parallel
FFT
…
Demodulator

OFDM symbol fundamentals
At 20 MHz BW, FFT=2048
OFDM symbol length 66.68 μs
• Robust for mobile radio channel with
the use of guard internal/cyclic
prefix (see next slide)
• Overheads of guard interval and
channel spacing are not excessive
6 OFDM data symbols per one 0.5 ms
slot
• Additionally one symbol for pilot
sequence (& TS), Shared Control
signaling and occasionally for
system info
copy of Np last samples
cyclic
prefix
OFDM symbol, Tsym
FFT length NFFT
Guard
Interval
symbol window
OFDM symbol before
CP insertion
delay
spread
cyclic
prefix
symbol window
cyclic
prefix
OFDM symbol before
CP insertion
OFDM symbol, T sym
FFT length N FFT
Guard
Interval
OFDM symbol at the transmitter
OFDM symbol at the receiver

Cyclic Prefix – Preventing Inter-symbol
Interference (ISI)
Having the cyclic prefix longer than the channel multi-path delay
spread prevents ISI
The part of the signal waveform itself is copied to be used and
cyclic prefix (instead of a break in transmission)

Maintaining sub-carriers orthogonal
The OFDMA refers indeed to the Orthogonal FDMA as the
parameters for the sub-carrier are chosen to that neighboring
sub-carriers have zero value the desired sampling point for any
sub-carrier
Sampling point for
a single sub-carrier
Zero value for
other sub-carriers
15 kHz
Total transmission bandwidth

OFDMA Transmitter
Windowing is needed for pulse shaping for meeting the spectrum masks
• This is even more needed if some clipping is applied (typical) in the
transmitter as that makes the spectrum wider compared to the ideal OFDM
spectrum
• Compare to pulse shaping filters with WCDMA
The length of the filters will “eat” part of the time from cyclic prefix
Serial
to
Parallel
X0
XN-1
x0
xN-1
IFFT
Parallel
to
Serial
Add
CP
Windowing
DAC
RF Section
Input
Symbols

Downlink Multiple Access – OFDMA
User multiplexing in sub-carrier domain
Smallest allocation is 12 sub-carrier i.e. the bandwidth of 180 kHz.
• Largest 20 MHz, supported by all devices (if specified for the given
frequency band)
Single Resource
Block
…
180 kHz
Total
System
Bandwidth
1 ms Allocation Period
…
Sub-carriers for the
First Symbol in a
Single Resource
Block
Resource Blocks for User 1

OFDMA Channel Estimation
Reference Signals
Symbols / Time Domain
Sub-carriers /
Frequency domain
•Channel estimation
based on reference
symbols.
•Interpolation in time
and frequency domain
• In WCDMA common
pilot channel (CPICH)
was used for this
(together with
reference symbols on
DCH)

OFDM challenges
Peak-to-average ratio of the transmitted signal (crest factor,
also referred in 3GPP discussions as Cubic Metric, CM)
Sensitivity to frequency error
• This addressed by having sufficiently large sub-carrier
spacing
• In case of too large frequency error, the sub-carriers start to
interfere each others

Why not to use OFDM in the uplink?
The transmitted OFDM signal should be seen as a sum of sinusoid
This is not suited for a highly linear, power efficient terminal amplifier
The envelope needs to be with as low Peak-to-Average Ratio (PAR) as
possible.
Power Amplifier sees this!
IFFT
…
Frequency domain
QAM modulated inputs
Time domain signal
(sum of sinusoids)
FFT
…
Frequency domain
QAM modulated outputs

SC-FDMA in LTE Uplink

SC-FDMA with CP
Sending only one symbol at the time results to low PAR envelope
• In 3GPP Cubic Metric being considered as it represents better the
device amplifier impact than PAR
This allows to benefit from the modulation PAR/CM properties in devices
This is important for small size devices aiming for up to 23 dBm TX
power.
frequency
Transmitter
Receiver
total radio BW (eg. 20 MHz)
Modulator Cyclic
Extension
Remove
Cyclic
Extension
FFT
MMSE
Equaliser
IFFT Demodulator Bits
Bits
frequency
Transmitter
Receiver
total radio BW (eg. 20 MHz)
Modulator Cyclic
Extension
Remove
Cyclic
Extension
FFT
MMSE
Equaliser
Bits
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
CM vs rolloff with different modulations
rolloff
CM
[dB]
SC pi/2-BPSK
SC QPSK
SC 16-QAM
OFDM pi/2-BPSK
OFDM QPSK
OFDM 16-QAM

SC-FDMA Transmitter Chain
The receiver is expected to
use e.g. frequency domain
equalizer
• This is simpler as ISI does
not need to be considered
due to the cyclic prefix
• Other possibilities exists
such as Turbo equalizer
This example uses the
frequency domain generation
of the SC-FDMA signal, in
theory could be generated
without FFT as well in the
transmitter. Use of FFT
however ensures good
spectral properties
Remove
Cyclic
Extension
FFT
MMSE
Equaliser
Remove
Cyclic
Extension
FFT
MMSE
Equaliser
Modulator
Bits
Modulator
Cyclic
Extension
IFFT
…
Sub-
carrier
mapping
frequency
Total radio BW (E.g. 20 MHz)
Transmitter
Receiver
DFT
IDFT

Uplink Multiple Access – SC-FDMA
User multiplexing in frequency domain
Smallest uplink bandwidth 180 kHz.
• Largest 20 MHz (terminal are required to able to receive & transmit up to
20 MHz, depending on the frequency band though.)
IFFT
Terminal 1 Transmitter
Terminal 2
Transmitter
frequency
frequency
IFFT
FFT
FFT
frequency BTS Receiver

SC-FDMA Change of data rate
…
Double
data rate
… Bandwidth
Symbol duration
•When data rate changes, more symbols per slot is being
transmitted. As the bandwidth increases the symbol duration
decreases.
•For double data rate the amount of FFT inputs in transmitter
doubles (as well as total BW) and symbol duration is halved

Physical Layer Structures

Introduction
• LTE physical layer based on OFDMA
downlink and SC-FDMA in the uplink
direction
• This is the same for both FDD and
TDD mode of operation
• There is no macro-diversity in use
• System is reuse 1, single frequency
network operation is feasible
– Interference control done by the BTS
scheduler, supported by the inter-BTS
information exchange (over X2 interface)
X2
X2

LTE Physical Layer Structure – Frame Structure
(FDD)
The slot structure (allocation with 1 ms sub-frame resolution) has been
designed to facilitate short round trip time
With TDD there were originally two different frame structures but agreement
was reached on a single TDD frame structure that is otherwise as with FDD
but some specific fields to enable also TD/SCDMA co-existence (China)
10 ms frame
0 1 19
18
…
0.5 ms slot
1 ms sub-frame

LTE Physical Layer Structure – Frame Structure
(cont)
Data Symbols
Control Symbols
D
L
Sub-carriers
0.5 ms Slot
1 ms Sub-frame
10 ms Radio Frame
…
0 1 2 3 19
18
17
1-3 symbols for control
(2-4 for 1.4 MHz)
Data symbols only in every 2nd symbol

LTE Physical Layer Structure – Downlink
The following downlink physical channels are defined
• Physical Downlink Shared Channel, PDSCH
– This is intended for the user data (compare with HS-PDSCH in
WCDMA)
• Physical Downlink Control Channel, PDCCH
• Physical Broadcast Channel, PBCH
• Physical Control Format Indicator Channel, PCFICH
• Physical Multicast Channel, PMCH (Not in Release 8)
• Physical Hybrid ARQ Indicator Channel, PHICH
Configuration
Normal cycli
c prefix kHz
15
=
Δf 7
kHz
15
=
Δf 6
Extended cyclic prefix
kHz
5
.
7
=
Δf 3
OFDMA Symbols
PMCH only

LTE Physical Layer Structure – Downlink
Reference Signal
1
1
1
Not used for
transmission on
this antenna port
Reference
signals on this
antenna port
Resource element
R0
R0
R0
R0
R0
R0
R0
R0
reference signal: R1
reference signal:
R1 R1
R1
R1
R1
R1
R1
R1
subframe x
subframe x
1RB
Needed for receiver channel estimation (like CPICH in WCDMA)
Sufficient distribution in time and frequency domain needed.

Downlink channels for data & control
(PDCCH/PDSCH)
Downlink control information in the few first symbols to indicate which
resources (resource blocks) are allocated for a given user (UL&DL!)
Respectively the uplink resources to be used are informed by eNode B
• PDCCH allocation is dynamic (see next slide for PCFICH)
• QPSK modulation for PDCCH.
Data Symbols
Control Symbols
D
L
U
L
Uplink Allocations
User 1 Data & Control
User 2 Data & Control
Frequency
Sub-carriers
0.5 ms slot

Other downlink channels
• Physical Broadcast Channel, PBCH
– This carriers the BCH (system information like RACH parameters)
• Physical Control Format Indicator Channel, PCFICH
– Indicates how many OFDM symbols (1 to 3) are used for PDCCH(s)
Physical Multicast Channel, PMCH
– MBMS (multicast) data
• Physical Hybrid ARQ Indicator Channel, PHICH
– HARQ feedback for uplink packets

Sub-frame structure
Short cyclic prefix
Long cyclic prefix
Copy
= Cyclic prefix
= Data
5.21 μs
16.67 μs
Sub-frame length is 1 ms for all bandwidths
• 0.5 ms is the slot length
• Originally it was planned to use 0.5 ms sub-frame but
signaling overhead was too excessive
Slot carries 7 symbols with short cyclic prefix or 6 symbols
with long cyclic prefix

Resource Blocks
Resource allocation can be done with Resource blocks
Resource block has bandwidth of 180 kHz, equal to 12
subcarriers
10 MHz = 50 resource blocks = 600 subcarriers
Resource block
180 kHz = 12
subcarriers
Subcarrier 15 kHz

Synchronization Signal in Downlink
Synchronization Signal is allocated in the 1.08-MHz block in the
middle of downlink bandwidth to faciliate UE cell search
ƒ Cell search procedure (see later slides) not dependent on system BW
Info is located in the end of slots 0 and 10 (In FDD)
ƒ Synchronisation Signal can indicate 504 (168 x 3) different values and
from those one can determine the location of cell specific reference
symbols
#0
Frame Tf = 10 ms
#19
1.08 MHz (= 6 resource blocks)
Slot 0.5 ms

Subcarrier Modulation
QPSK
2 bits/symbol
16QAM
4 bits/symbol
64QAM
6 bits/symbol
In both directions QPSK, 16QAM or 64QAM are used, depending on the
channel (Control channels to be using mainly QPSK, RACH sequences are
phase modulated sequences but not pure QPSK)

Downlink Physical Layer Parameters
3.0 MHz 5 MHz 10 MHz 15 MHz 20 MHz
Subframe (TTI) 1 ms
Subcarrier 15 kHz
FFT 128 256 512 1024 1536 2048
Subcarriers1 72+1 180+1 300+1 600+1 900+1 1200+1
1DC subcarrier included
Symbols per frame 7 with Short CP and 6 with Long CP
Cyclic prefix 5.21 μs with Short CP and 16.67 μs with Long CP
1.4 MHz

Channel Coding
•The user data (including
paging messages and
multicast data) are turbo
encoded, (encoder from
WCDMA)
•The control information with
convolutional encoding
– Note however open issues in
the specs currently
– Tail biting convolutional codes
to be used
• Turbo codes would be
difficult to beat with big
margin thus no point
adapting something
different
CRC Attachment
Code Block
Segmentation and
CRC Attachment
Channel Coding
Rate Matching
Channel Coding
Code Block
Concatenation
Data and Control
Multiplexing
Channel
Interleaver
Control
Data

LTE Physical Layer Structure – Uplink
The following uplink physical channels are defined
• Physical Uplink Shared Channel, PUSCH
– This is intended for the user data (compare with HSUPA in WCDMA,
but this is now fully dynamic allocation not just rate control like in
WCDMA)
• Physical Uplink Control Channel, PUCCH
• Physical Random Access Channel, PRACH

Uplink Subframe Structure (PUSCH)
In the uplink direction the QAM modulation is sending only one
symbol at the time.
Momentary data rate (controlled by the eNode B scheduler)
depends on the allocated transmission bandwidth (and CP
length)
Reference Symbol
Normal CP slot
0 1 2 3 4 5 6
Extended CP slot
0 1 2 3 4 5

Uplink resource mapping
Subcarriers
Reference Symbols
Resource Block
Resource Elements
Modulation
Symbols for
Data
Time domain
Signal Generation
0.5 ms slot
Reference Symbols
Control Information Elements
(Only part of the resource elements)
Modulation
Symbols for
Control
Control Information Elements

Random Access Channel (RACH)
The RACH operation uses around 1.08 MHz MHz bandwidth
This is equal to 6 resource blocks of 180 kHz
Similar ramping as with WCDMA (due inaccuracy of absolute
power level setting in devices, +/- 9 dB in WCDMA, similar
values also in LTE though uplink power setting dynamic range a
bit smaller than in WCDMA)
307200×Ts
TPRE TGT
TCP
Preamble
CP
0.1 ms 0.1 ms
0.8 ms

Physical Layer Compared to HSPA
LTE builds on the learning of several WCDMA/HSPA Releases
and covers from the start HARQ, BTS scheduling and adaptive
coding and modulation (+ multiple antenna TX/RX with MIMO)
Feature
Multiple Access
Fast power control
Adaptive modulation
BTS based scheduling
LTE
OFDMA
SC-FDMA
No
Yes
Time/Freq
HSUPA
WCDMA
Yes
Yes
Time/Code
Fast L1 HARQ Yes Yes
HSDPA
WCDMA
No
(associated DCH only)
Yes
Time/Code
Yes
Largest BW 20 MHz 5 MHz 5 MHz
Soft handover No Yes No
(associated DCH only)

Physical Layer Procedures

LTE Uplink Power Control
LTE uplink is using also closed loop power control, rate slower
than with WCDMA
• This needed due reuse 1 and to limit uplink receiver
dynamic range
Power control commands connection with scheduling grants
Control over power spectral density, not absolute power
-> Thus power is changing based on the BW used (as
allocated by the BTS)
frequency
frequency
Power per Hz unchanged
TTI 1
TTI 2

LTE Uplink Power Control (cont)
Cell wide overload indicator (OI) exchanged over X2 between nodes on a
slow basis,
• Expected average delay is in the order or 20 ms, number of bits is still for
discussion in 3GPP
• This can be used for Inter-Cell Interference Coordination (ICIC) as well
UE
eNode B
Serving eNode B
Overload
indicator
Scheduling and TPC
Uplink data
X2
A neighboring
eNode B
Interference
To AGW

LTE Timing Advance
When UE has previously established time alignment:
• TA update rate: on a per-need basis, 2 Hz is fast enough also for high speed UEs
• Granularity of TA signalling: 0.52us
•What to base the TA command on:
– When the UE has data to transmit, implementation issue in Node B (e.g. based on
sounding RS, CQI)
– If the UE has no data to transmit, e.g. periodic signals such as sounding RS may be
ordered
• How to transmit TA in the downlink: Part of MAC layer signalling
When no TA is established or UE is out of sync
• TA command is based on RACH preamble
• Initial TA will have to cover the full cell range, part of RACH procedure
UE
eNode B
Timing Advance
Uplink data or RACH

LTE Channel Quality Information (CQI)
• To enable frequency domain scheduling, one needs channel
CQI not only on the time domain (like in HSDPA) of the
expected link quality but also in the frequency domain.
• Different combinations exists in specs, and also event and
period reporting options (-> a lot for testing) :
– Wideband feedback (this is also always together with following
options)
ƒ UE to report one wideband value
– Higher Layer-configured sub-band feedback or UE selected sub-bands
ƒ Delta to configured sub-bands is signaled or in the UE selected case UE
report M best sub-bands
UE
eNode B
Data with modulation &
Position in frequency domain
Based on the CQI received
CQI

Cell Search Procedure
• Upon power on, UE will search for the primary synchronization
signals (3 different possibilities)
• In Step 2 UE will determine out of each 168 values the which
of the 168 possible secondary synchronization signal is used
– Thus total of 504 different values possible for the physical cell ID
• The synchronization signal information is also used to
determine what kind of cell specific reference symbols are in
use in the cell to facilitate demodulation of BCH after obtaining
frequency and timing synchronization from synchronization
signals
• After a successful BCH decoding UE may access the system
from the radio perspective (see later RACH procedure)

Physical Layer Retransmission (HARQ) procedure
• 8 processes are used for continuous operation both uplink and
downlink (no process number configuration like in HSDPA)
•HARQ principle used is stop-and-wait-ARQ
PUSCH/PDSCH 1 2 3 4 5 6 1 2
…
CRC Check Result Fail Pass
NACK
ACK
RLC layer
1st TX 1st TX
2nd TX
1st TX (new packet)
…
From scheduler buffer
7 8

LTE Measurements
• measurements from LTE on LTE (intra-LTE):
– UE measurements:
ƒ RSRP (reference signal received power ),
ƒ E-UTRA carrier RSSI (received signal strength indicator)*,
ƒ RSRQ (reference signal received quality)
– eNode B measurement:
ƒ DL reference signal transmit power
• measurements from LTE on other systems:
– UTRA FDD: CPICH RSCP, carrier RSSI, CPICH Ec/No
– GSM : GSM Carrier RSSI
– UTRA TDD: P-CCPCH RSCP ,carrier RSSI
* Not reported as part of the RSRQ definition

LTE Measurements – Carrier RSSI & RSRQ
E-UTRA Carrier Received Signal Strength Indicator, comprises the total
received wideband power observed by the UE from all sources, including
co-channel serving and non-serving cells, adjacent channel interference,
thermal noise etc.
Reference Signal Received Quality (RSRQ) is defined as the ratio
N×RSRP/(E-UTRA carrier RSSI), where N is the number of RB’s of the
E-UTRA carrier RSSI measurement bandwidth. The measurements in the
numerator and denominator shall be made over the same set of resource
blocks.

LTE Measurements – RSRP & DL Reference Signal
Transmitted Power
Downlink reference signal transmit power is determined for a considered
cell as the linear average over the power contributions (in [W]) of the
resource elements that carry cell-specific reference signals which are
transmitted by the eNode B within its operating system bandwidth.
Reference signal received power (RSRP) is determined for a considered
cell as the linear average over the power contributions (in [W]) of the
resource elements that carry cell-specific reference signals within the
considered measurement frequency bandwidth.
If receiver diversity is in use by the UE, the reported value shall be
equivalent to the linear average of the power values of all diversity
branches.

RACH Procedure
• RACH procedure = preamble + random access response
• Any user data or signaling data is carried on the shared data
channel. RACH does not carry data (different from WCDMA
Release 99)
• RACH occupies 6 resource blocks in a sub-frame
– The eNode B may also schedule data in the resource blocks reserved
for random access channel preamble transmission.
• Power ramping between preambles
Downlink / eNode B
PUSCH
PRACH
response
Uplink / UE
Preamble
Not detected
UE specific data
Preamble
Next
PRACH
resource
On the resources
indicated by
PRACH response

LTE TDD Aspects

TDD Multiple Access
• In LTE TDD mode same
multiple access as in FDD
• This is a big difference
compared to WCDMA
where TDD was totally
different
– Some harmonization was
done e.g. chip rates and
channel coding solutions
• From market
perspective China
Mobile pushing this
– As evolution step for the
on-going TD-SCDMA
deployment
UE with TDD support
TDD eNode B
OFDMA
SC-FDMA
f1
f1
Downlink TX
allocation
Time
Uplink TX
allocation
Time

LTE TDD Frame Structure
TDD may change between uplink and downlink either with 5 or 10 ms period
The specific fields (DwPTS, GP, UpPTS) are inherited from TD-SCDMA
• GP = Guard Period, DwPTS/UpPTS = DL/UL pilots
• 1 ms sub-frame otherwise same as FDD UL or DL sub-frame
10 ms frame
0.5 ms slot
1 ms sub-
frame
One half-fame (5 ms)
UpPTS
DwPTS
GP
Change between DL and UL

TD-SCDMA co-existence with LTE TDD
• With the common frame structure (& slot) duration it is still
possible to parameterize the LTE TDD mode to operation so
that the site can have compatible uplink and downlink split
– This would need to be rather static parameter
0.5 ms slot
1 ms LTE TDD sub-frame
UpPTS
DwPTS
GP
Change between DL and UL
…
…
TD-SCDMA slot
Adjusted relative timing to avoid UL/DL overlap

Differences in procedures for TDD
The reason for differences procedures is the needed change
between uplink and downlink
• This impacts especially the control signaling
• Cell search symbols (PSS and SSS) have different location
• ACKs/NACks in one go more than in FDD (with varying
timing, see next slide)
DL UL UL DL DL UL UL DL
S S
SSS
PSS
S-RACH/SRS
RACH
P-BCH D-BCH
SSS
PSS
S-RACH/SRS
RACH
SF#0 SF#2 SF#3 SF#4 SF#5 SF#7 SF#8 SF#9
1 ms
SF#1 SF#6

Differences in procedures for TDD - HARQ
The HARQ timing is not constant like in FDD
• This has made some combinations not feasible (like semi-
persistent scheduling + TTI bundling) in TDD.
Data DATA
3ms
1ms
Data ACK DATA ?? ACK
3ms 3ms 3ms
5ms
1ms
ACK ACK
3ms
1ms
3ms
3ms DATA
(a) Conceptual example of FDD HARQ Timing (propagation delay and timing advance is ignored)
(b) Conceptual example of TDD HARQ Timing (special subframe is treated as ordinary DL subframe)

TDD performance – For coverage FDD had
advantage
UL Coverage for TDD and FDD, UE target bitrate 2 Mbps
3
8
13
18
23
28
33
38
43
48
0.00 0.10 0.20 0.30 0.40 0.50
Distance [km]
#
of
PRB
0.00
0.50
1.00
1.50
2.00
2.50
Bitrate
[Mbps]
UE BW FDD
UE BW TDD
Bitrate FDD
Bitrate TDD
Data rates
Resources
When coming closer to cell edge, TDD needs to earlier to try to
increase bandwidth as TX time is reduced

LTE Layer 2/3

LTE Protocol Layers
RRC:
• Broadcast of system information
• Radio connection & Radio bearers
• Paging, handovers, QoS
management, radio measurement
control
RLC:
• Retransmission control (ARQ)
• Segmentation
• Flow control towards aGW
MAC:
• Mapping & mux of logical channels to
transport channels
• Traffic volume measurement reporting
• Hybrid-ARQ
• Priority handling
PHY:
• FEC encoding/decoding
• Error detection
• Support of HARQ
• Modulation/demodulation
• Frequency and time synchronization
• Power control, antenna diversity,
MIMO
RRC
RLC
MAC
Physical Layer
PDCP
Transport Channels
Logical Channels
Radio Bearers
Control-plane User-plane
L1
L2
L3
PDCP:
• Ciphering
• Header Compression

LTE layer 2
The Layer 2 protocols (MAC & RLC), terminate in the BTS
(known in 3GPP as eNode B)
Also PDCP (Packet Data Convergence Protocol) terminates
in the eNode B
User Plane LTE protocol stacks
PDCP
UE
RLC
MAC
Physical Layer
PDCP
eNode B
RLC
MAC
Physical Layer

LTE layer 2 Structure Header
Compressions
Ciphering

Layer 2 (MAC)
The Medium Access Control (MAC) signaling is also terminated in eNode
B, similar to MAC-hs with HSDPA (or MAC-e with HSUPA)
The transport channels from the MAC layer are mapped to the physical
channels, and respectively the MAC layer provides the logical channels to
RLC layer.
The following transport channels are defined in the downlink:
ƒ Broadcast Channel (BCH)
ƒ Downlink shared Channel (DL-SCH)
ƒ Paging Channel (PCH)
ƒ Multicast Channel (MCH)
In the uplink
ƒ Uplink Shared Channel (UL-SCH)
ƒ Random Access Channel (RACH)
• No DCH like in WCDMA!

MAC PDU Structure
MAC header MAC Control Elements MAC SDU MAC SDU
… Padding
Payload with type indicated in the header
DL-SCH: Types of payload
elements
• Logical channel identity
• CCCH
• UE contention resolution
identity
• Timing Advance
• DRX command
• Field lengths
UL-SCH: Types of payload elements
• Logical channel identity
• CCCH
• Power Headroom Report
• C-RNTI
•Short Buffer Status Report
• Long Buffer Status Report

LTE layer 2 – RLC AM
AM-SAP
DCCH/
DTCH
Transmission buffer
Data Field
Receiving buffer
Reassembly
DCCH/
DTCH
Transmitting side Receiving side
AMD Header
STATUS
Data Field
AMD Header
Segmentation/
concatenation
Retransmission
buffer
Control
Biggest difference to WCDMA: Lack of ciphering, data
comes ciphered from PDCP layer
Header has sequence number and info of the last received
packet

LTE layer 2 – RLC UM
UM-SAP
DCCH/ DTCH
Transmission buffer
Data Field
Receiving buffer
& HARQ Reordering
Reassembly
AMD Header Data Field
AMD Header
Segmentation/
concatenation
DCCH/ DTCH
Also un-acknowledged mode supported (in figure) and
transparent mode (not shown)
Transparent mode RLC only to common channels (BCCH,
CCCH and PCCH) which do not have HARQ

LTE layer 2 – PDCP
NAS
RLC
Sequence
numbering
RLC
Header
compression
Integrity
protection
User Plane
Control Plane
Ciphering
Data Field
PDCP Header Data Field
PDCP Header
Deciphering
Re-ordering
Integrity
protection
User Plane
Control Plane
Header
decompression
In WCDMA PDCP was only for user plane, now also for
control plane due ciphering

Layer 3 (RRC)
• The Radio Resource Control (RRC) signaling is also terminated in eNodeB
(compared to RNC in WCDMA)
• One of the enablers for the flat model is the lack of macro-diversity
• No need for RNC like functional element -> everything radio related can
be terminated in eNodeB
• RRC to handle: Broadcast, Paging, RRC connection management,
Mobility managements and UE measurements …
– Only two states in LTE RRC (see later slides)
Control Plane LTE protocol stacks
RRC
UE
RLC
MAC
Physical Layer
RRC
eNodeB
RLC
MAC
Physical Layer
PDCP PDCP

Mapping of the Logical/Transport Channels to L1
In the uplink direction both control and user data all mapped to PUSCH
RACH UL-SCH
PUSCH
PRACH
Physical Channels
Logical Channels CCCH DCCH DTCH
In the downlink direction unicast user data on PDSCH, multicast
data can be also on PMCH. RRC Control information all on DL-SCH
BCH DL-SCH
PDSCH
PBCH
CCCH DCCH DTCH MCCH MTCH
PDCCH
PCH
PCCH BCCH
MCH
PMCH
Transport Channels
Physical Channels
Logical Channels
Transport Channels

LTE Architecture

LTE Architecture Evolution
GGSN
Node B
HSPA R6
SGSN
LTE R8
RAN
eNode B
SAE
Gateway
Only user plane elements shown!
RNC
The LTE architecture is
flat, only two nodes for
the user data
• See later slides for
details
This is similar that is
enabled in I-HSPA when
deployed together with
the one tunnel solution
Also the ciphering is in
eNodeB
One key facilitator is lack
of macro-diversity (soft
handover)

LTE Architecture – Control Plane
The interface between
RAN & Core network is
called S1 interface
Interface between
eNodeBs is named X2
Note: for ciphered RRC messages
also PDCP used
S1_MME
between MME&
eNodeB
X2
RRC
UE
RLC
MAC
Physical Layer
RRC
eNode B
RLC
MAC
Physical Layer
RRC
eNode B
RLC
MAC
Physical Layer MME
S1_MME
S1_MME
NAS NAS
MME = Mobility Management Entity

LTE Architecture – X2 interface
The X2 interface has the following
functionalities:
• In inter- eNode B handover to
facilitate handover and provide data
forwarding
• In RRM to provide e.g. load
information to neighboring eNode Bs
to facilitate interference
management
•X2 is a logical interface i.e. it can
routed via core network as well,
does not need direct site-to-site
connection
– User data only in case of handover
event (data forwarding unit rerouted
from WG)
X2
PDCP
eNode B
RLC
MAC
Physical Layer
RRC
PDCP
eNode B
RLC
MAC
Physical Layer
RRC

X2 Interface – Interference Management
Downlink TX
eNode B
…
One PRB = 180
kHz
… …
Measurement Granularity in Frequency
In the downlink direction measurement is: Maximum Tx Power per PRB normalized
Threshold level
X2-interface
eNode B
PRBs Exceeding
Threshold level

X2 Interface – Interference Management (2)
Uplink RX
eNode B
One PRB = 180 kHz
…
Uplink RX bandwidth
In the uplink direction measurement is: Maximum Tx Power per PRB normalized
Threshold levels
for Interference
X2-interface
eNode B
Interference
Level of PRBs
Measured
Interference

LTE Architecture – S1 interface
The S1 interface has the following
functionalities:
• It connects the eNode B to the evolved
packet core. Divided to control plane
(S1_MME) and user plane (S1_U) parts
• S1_U carries the user data to SAE
gateways
• S1_MME connects to the mobility
management entity
• Carriers the NAS (non access stratum)
signaling (authentication etc. protocols
between core and UE)
• Separate ciphering for S1 interface (as
PDCP in eNode B)
RRC
eNode B
RLC
MAC
Physical Layer
MME
S1_MME
S1_U
SAE Gateways
PDCP

LTE/SAE Architecture (Radio and Core)
PCRF
MME
HSS
IP
Networks
Data
Control
S1_MME
Serving SAE
Gateway
eNode B
S1_U
PDN SAE
Gateway
S11
SGI
Operator Services
(IMS etc…)
Radio
eNode B
X2

LTE Peak Bit Rates

LTE Structure for 10 MHz with 2x2 MIMO
10 ms = 10 subframes = 140 symbols
=PDSCH
=PBCH
=Reference
=Synchronization
=PCFICH
=PDCCH
=PHICH
=Reserved for
4x4 MIMO
PCFICH PCFICH PCFICH PCFICH PCFICH PCFICH PCFICH PCFICH PCFICH PCFICH
Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref.
PHICH PHICH PHICH PHICH PHICH PHICH PHICH PHICH PHICH PHICH
PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH
PDCCH Rsvd Rsvd PBCHPBCHPBCHPBCH PDCCH PDCCH PDCCH PDCCH PDCCH Rsvd Rsvd PDCCH PDCCH PDCCH PDCCH
Ref. Ref. Rsvd Rsvd Ref. Rsvd PBCHPBCHRef. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Rsvd Rsvd Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref.
Ref. Ref. S-SynP-SynRef. Rsvd PBCHPBCHRef. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. S-SynP-SynRef. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref. Ref.
PDCCH S-SynP-SynPBCHPBCHPBCHPBCH PDCCH PDCCH PDCCH PDCCH PDCCH S-SynP-Syn PDCCH PDCCH PDCCH PDCCH
PCFICH S-SynP-SynPBCHPBCHPBCHPBCH PCFICH PCFICH PCFICH PCFICH PCFICH S-SynP-Syn PCFICH PCFICH PCFICH PCFICH
PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH PDCCH PDCC
10 MHz = 600 subcarriers

LTE Structure for Middle 1.4 MHz with 2x2 MIMO
1.4 MHz
10 ms = 10 subframes
=PDSCH
=PBCH
=Reference
=P-Synchronization
=PCFICH
=PDCCH
=PHICH
=Reserved for 4x4 MIMO
=S-Synchronization

PDCCH S-Syn P-Syn PBCH PBCH PBCH PBCH
Ref. Ref. S-Syn P-Syn Ref. Rsvd PBCH PBCH Ref.
LTE Structure – One Example Resource Block
1 ms subframe
1 resource block = 12
subcarriers = 180 kHz
=PDSCH
=PBCH
=Reference
=P-Synchronization
=PCFICH
=PDCCH
=PHICH
=Reserved for 4x4 MIMO
1.4 MHz =S-Synchronization

Modulation coding 1.4 MHz 3.0 MHz 5.0 MHz 10 MHz 15 MHz 20 MHz
QPSK 1/2 Single stream 0.7 2.1 3.5 7.0 10.6 14.1
16QAM 1/2 Single stream 1.4 4.1 7.0 14.1 21.2 28.3
64QAM 3/4 2x2 MIMO 6.6 18.9 31.9 64.3 96.7 129.1
64QAM 1/1 2x2 MIMO 8.8 25.3 42.5 85.7 128.9 172.1
64QAM 1/1 4x4 MIMO 16.6 47.7 80.3 161.9 243.5 325.1
Peak Data Rates – Downlink
• Following overheads reduced
– Synchronization, reference, PBCH, PCFICH, PHICH and 1 PDCCH symbol
• Relative overheads
– Reference symbol overhead 9.5% with 2x2 MIMO
– PDCCH overhead 7.1% with single symbol (two symbols with 1.4 MHz)
– Other overheads <1% with 10 MHz bandwidth
• Peak rate 172 Mbps with 2x2 MIMO and 20 MHz
• Following overheads not reduced: CRC, L2/L3 headers, IP headers

Peak Data Rates – Uplink
• Following overheads reduced
– 1 symbol for reference symbol
– 1 resource block for PUCCH
• Relative overheads
– Reference symbol overhead 14.3%
– PUCCH overhead 2.5%
• Peak rate 57 Mbps with 20 MHz and 16QAM
• Following overheads not reduced: CRC, L2/L3 headers, IP headers
Modulation coding 1.4 MHz 3.0 MHz 5.0 MHz 10 MHz 15 MHz 20 MHz
QPSK 1/2 Single stream 0.7 2.0 3.5 7.1 10.8 14.3
64QAM 1/1 V-MIMO (cell) 8.6 24.2 41.5 84.7 129.6 171.1

LTE UE Categories
• All categories support 20 MHz
• 64QAM mandatory in downlink, but not in uplink (except Class 5)
• 2x2 MIMO mandatory in other classes except Class 1
• Class 3 expected initially
Class 1 Class 2 Class 3 Class 4 Class 5
10/5 Mbps 50/25 Mbps 100/50 Mbps 150/50 Mbps 300/75 Mbps
Peak rate DL/UL
20 MHz
RF bandwidth 20 MHz 20 MHz 20 MHz 20 MHz
64QAM
Modulation DL 64QAM 64QAM 64QAM 64QAM
16QAM
Modulation UL 16QAM 64QAM
16QAM 16QAM
Yes
Rx diversity Yes Yes
Yes Yes
1-4 tx
BTS tx diversity
Optional
MIMO DL 2x2 4x4
2x2 2x2
1-4 tx 1-4 tx 1-4 tx 1-4 tx

LTE Latency

Latency Evolution for HSPA and LTE
0
10
20
30
40
50
60
70
80
90
100
HSDPA/R99 HSPA RU10 HSPA RU30 LTE scheduled LTE -
preallocated
ms
RNC + core
BTS + Iub
Retransmissions downlink
Retransmissions uplink
Air interface
Scheduling request + grant
UE
Commercial
Evolution
“Typically, more than 80% of all data bursts in WCDMA/HSPA networks are
so small (<100kB) that they are more sensitive to latency than throughput.“
Source: Major global operator

NSN LTE Latency Measurements
Ping LTE
0
5
10
15
20
25
30
0 10 20 30 40 50 60 70 80
Ping number
ms
Stabile ping
<20 ms

0
5
10
15
20
25
30
LTE scheduled LTE scheduled
(measured)
LTE - preallocated
ms
Measured end-to-end
RNC + core
BTS + Iub
Retransmissions downlink
Retransmissions uplink
Air interface
Scheduling request + grant
UE
Expectations vs Measurements
Perfect match
with
expectations

LTE Link Budgets

Link Budget – Uplink
• LTE 64 kbps at least similar link budget as HSPA 64 kbps or
GSM voice
23 dBm terminal
2 resource blocks
for 64 kbps = 360
kHz
Small interference
margin (low capacity)
No soft handover
gain
Uplink
Data rate [kbps] Voice 64 64
GSM HSUPA LTE
Transmitter - UE
a Max tx power [dBm] 33.0 23.0 23.0
b Tx antenna gain [dBi] 0.0 0.0 0.0
c Body loss [dB] 3.0 0.0 0.0
d EIRP [dBm] 30.0 23.0 23.0
Receiver - Node B
e Node B noise figure [dB] - 2.0 2.0
f Thermal noise [dBm] -119.7 -108.2 -118.4
g Receiver noise floor [dBm] - -106.2 -116.4
h SINR [dB] - -17.3 -7.0
i Receiver sensitivity [dBm] -114.0 -123.4 -123.4
j Interference margin [dB] 0.0 3.0 1.0
k Cable loss [dB] 2.0 2.0 2.0
l Rx antenna gain [dBi] 18.0 18.0 18.0
m MHA gain [dB] 2.0 2.0 2.0
n Fast fade margin [dB] 0.0 1.8 0.0
o Soft handover gain [dB] 0.0 2.0 0.0
Maximum path loss 162.0 161.6 163.4
Delta [dB] Reference -0.4 1.4

Link Budget – Downlink
• Downlink 1 Mbps link budget similar to uplink 64 kbps
40 W BTS
2 dB cable loss
(could be avoided
with RF head)
10 MHz bandwidth
Data rate [kbps] Voice 1024 1024
GSM HSDPA LTE
Transmitter - Node B
a Tx power [dBm] 44.5 46.0 46.0
b Tx antenna gain [dBi] 18.0 18.0 18.0
c Cable loss [dB] 2.0 2.0 2.0
d EIRP [dBm] 60.5 62.0 62.0
Receiver - UE
e UE noise figure [dB] - 7.0 7.0
f Thermal noise [dBm] -119.7 -108.2 -104.5
g Receiver noise floor [dBm] - -101.2 -97.5
h SINR [dB] - -5.2 -9.0
i Receiver sensitivity [dBm] -104.0 -106.4 -106.5
j Interference margin [dB] 0.0 4.0 4.0
k Control channel overhead [%] 0.0 % 20.0 % 20.0 %
l Rx antenna gain [dBi] 0.0 0.0 0.0
m Body loss [dB] 3.0 0.0 0.0
Maximum path loss 161.5 163.4 163.5
Delta [dB] Reference 1.9 2.0

LTE Downlink Bit Rates
– Interference Limited, Other Cells 100% Loaded
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
10
20
30
40
50
60
70
80
90
100
Distance from BTS [relative to cell radius, 1=cell edge]
Mbps
LTE 20 MHz
LTE 10 MHz
LTE 5 MHz
HSDPA 5 MHz
Cell edge G-factor = -4 dB
2x2 MIMO
Clear benefit of larger
bandwidth over the
whole cell area
Median data rate 10-20
Mbps for 10-20 MHz
LTE

Coverage Impact of the Spectrum
Okumura-Hata with 6 dB lower antenna gain with 700 and 900.
TDD link budget loss 3 dB.
Typical site coverage area in urban area
4.2
3.2
2.1
1.7
1.0
0.6
0.0 1.0 2.0 3.0 4.0 5.0
700
900
1800
2100
2600 FDD
2600 TDD
MHz
km2

Packet Scheduling

Frequency Domain Scheduling
Frequency
Resource block
Transmit on those resource
blocks that are not faded
Carrier bandwidth
• Frequency domain scheduling uses those resource blocks that are not
faded
• Not possible in CDMA based system

Gain of Frequency Domain Scheduling
• Up to 40% gain from frequency domain scheduling with
– low km/h
– large number of users
– no MIMO
0 5 10 15 20 25 30
UE speed [kmph]
40% FDPS gain
Frequency selective CQI
Wideband CQI (no FDPS)
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
Average
cell
throughput
[Mbps]

Time and Frequency Domain Schedulers
FD Scheduler
Filter of
NMaxFDM
Packet Scheduler
Control channel
resource check
TD Scheduler
Buffer
status
CQI QoS
UE to
PRB
Mapping
CQI
Past Averaged Throughput,
Scheduled Throughput
Scheduled Throughput per PRB
HARQ
• Time domain scheduling provides QoS differentiation
• Frequency domain scheduling provide efficiency gains

Inter Cell Interference Coordination (ICIC)
• LTE is designed for frequency reuse of one ⇒
no frequency planning required
• Inter-site interference coordination is possible
by exchanging load information over X2
interface = soft frequency reuse
• Options: proactive and reactive schemes
• Simulations show no clear performance gains
from inter-site interference coordination
• Our recommended default configuration is
frequency reuse one with flat power spectrum
and fast dynamic QoS-aware packet
scheduling
X2
X2

LTE Capacity

Spectral Efficiency Relative to 10 MHz
0%
20%
40%
60%
80%
100%
120%
LTE 1.4
MHz
MIMO
LTE 3
MHz
MIMO
LTE 5
MHz
MIMO
LTE 10
MHz
MIMO
LTE 20
MHz
MIMO
Downlink
Uplink
LTE Capacity vs Bandwidth
-40% -13% Reference
• LTE maintains high efficiency with bandwidth down to 3.0 MHz
• The differences between bandwidths come from frequency scheduling
gain and different overheads

LTE Capacity vs Bandwidth (2)
• Larger bandwidth brings multiple gains: higher capacity, higher data
rates and higher efficiency
Sector capacity
1.5
4.4
8.3
17.4
36.2
0.6 2.1
3.8
7.9
16.3
0
5
10
15
20
25
30
35
40
LTE 1.4
MHz MIMO
LTE 3 MHz
MIMO
LTE 5 MHz
MIMO
LTE 10 MHz
MIMO
LTE 20 MHz
MIMO
LTE bandwidth
Mbps
Downlink
Uplink

LTE Spectral Efficiency
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1x2 MRC 2x2 MIMO 4x2 MIMO 2x4 MIMO
(est)
4x4 MIMO
bps/Hz/cell
LTE Capacity with MIMO
UE Class 1-5
UE Class 2-5
UE Class 2-5
UE Class 5
R1-072444
• Only minor capacity gain from more transmission branches at BTS
• Typically capacity gain <15% when number of transmission branched
doubled
UE Class 5
<15%
<15%
<15%

0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0 5 10 15 20 25 30 35 40 45 50
mean registered UE per cell [-]
Spatial
Multiplexing
Utilization
[%]
2x2 Dynamic MIMO CL - R 167m
High MIMO usage in
small isolated cell.
MIMO usage
decreases in larger
cells.
MIMO Dual Stream Utilization – Isolated Cell
MIMO usage
decreases with large
number of UEs.

0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0 5 10 15 20 25 30 35 40 45 50
mean registered UE per cell [-]
Spatial
Multiplexing
Utilization
[%]
MIMO Dual Stream Utilization – Hexagonal Grid
MIMO dual stream
usage is very limited in
high loaded system.
Typically <10%.

Impact of LTE BTS Power to Capacity
ISD (Km) Power
SE
(bit/Hz/Se
ctor
Sector
Capacity
(Mbps)
Gain
Respect
(20W+20W)
0.5 20W+20W 1.54 15.4 0.0%
0.5 30W+30W 1.54 15.4 0.0%
0.5 40W+40W 1.54 15.4 0.0%
1.7 20W+20W 1.55 15.5 0.0%
1.7 30W+30W 1.51 15.1 -2.6%
1.7 40W+40W 1.52 15.2 -1.9%
3.2 20W+20W 1.28 12.8 0.0%
3.2 30W+30W 1.33 13.3 3.9%
3.2 40W+40W 1.37 13.7 7.0%
ISD (Km) Power
SE
(bit/Hz/Se
ctor
Sector
Capacity
(Mbps)
Gain
Respect
(20W+20W)
0.5 20W+20W 1.58 15.8 0.0%
0.5 30W+30W 1.58 15.8 0.0%
0.5 40W+40W 1.58 15.8 0.0%
1.7 20W+20W 1.43 14.3 0.0%
1.7 30W+30W 1.47 14.7 2.8%
1.7 40W+40W 1.5 15 4.9%
3.2 20W+20W 1.12 11.2 0.0%
3.2 30W+30W 1.2 12 7.1%
3.2 40W+40W 1.25 12.5 11.6%
2.1GHz
700MHz
Only large cells show
gain (+7%) from more
than 40 W power per 10
MHz at 700 MHz.
Slightly higher gain
(+12%) from 80 W vs 40
W at 2.1 GHz band.

Impact of Uplink Cell Size to Capacity
0.86
0.62
0.56
0.85
0.68
0.83
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
1
S
p
e
c
tr
a
l
E
ffi
c
i
e
n
c
y
(b
p
s
/
h
z
/
s
e
c
to
r
)
10M-500m-FB-2Rx-2G 10M-MC3-FB-2Rx-2G 10M-3.2Km-FB-2Rx-2G
10M-500m-FB-2Rx-700MHz 10M-MC3-FB-2Rx-700MHz 10M-3.2Km-FB-2Rx-700MHz
2GHz 700MHz
1.17
0.62
0.92
0.85
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1
S
p
ectral
E
fficien
cy
(b
p
s/Hz
/secto
r)
2GHz-10MHz-FB-2Rx 2GHz-10MHz-FB-4Rx
700MHz-10MHz-Fb-2Rx 700MHz-10MHz-Fb-4Rx
2.1GHz 700MHz
48.3% 37.6%
Highest capacity in small cells
(0.5 km). Higher frequency (2.1
GHz) suffers more from larger
cell size (1.7-3.2 km).
0.5
Km
1.7
Km
3.2K
m
0.5
Km
1.7
Km
3.2
Km
4rx diversity in uplink helps to
extend cell size and capacity
especially at 2.1 GHz band.

Maximum LTE Subscribers with 1+1+1 @ 20 MHz
Cell capacity 35 Mbps
Convert Mbps to GBytes
Busy hour average loading
50%
Busy hour carries 15% of
daily traffic
30 days per month
3 sectors per site
20 MHz x 1.74
bps/Hz/cell
/ 8192
x 50%
/ 15%
x 30
x 3
x 3 ⇒ 4600 GB/site/month
3600 seconds per hour x 3600
Total 920 subs/site
5 GB traffic per user / 5 GB
Cell capacity 35 Mbps
Required user data rate
3 sectors per site
From simulations
1 Mbps
x 3
Overbooking factor 20
Total 1050 subs/site
Traffic volume based dimensioning Data rate based dimensioning
Busy hour average
loading 50%
x 50%
Up to 1000 broadband
subscribers can be
supported per LTE BTS site

Wireless Capacity Limits – Example Elisa
Finland

Estimated max network throughput
360.0
108.0
2.7
0
50
100
150
200
250
300
350
400
1xHSPA today 5xHSPA+ 5xHSPA + 2x20 MHz
LTE
Gbps
Macro Cell Capacity Limits – Throughput
Assumptions
Busy hour load 50%
Sites carrying 50% of traffic 15%
Voice share 10%
Sectors 3
Busy hour share 15%
HSPA cell throughput 4.0
HSPA+ cell throughput 6.0
LTE 10 MHz cell throughput 35.0
Traffic per sub per month [GB] 1.0

Macro Cell Capacity Limits – Data Volumes
Total network level data volume
14.6
291.6
1047.6
0
200
400
600
800
1000
1200
1xHSPA today 5xHSPA+ 5xHSPA + 2x20
MHz LTE
TB/day
Total mobile data in Finland
was 17 TB/day on average
during 2H/2008. Assuming
Elisa market share 50% gives
around 10 TB for Elisa.
20x growth
potential
70x growth
potential

Maximum Subscribers
0.4
8.7
31.4
0
5
10
15
20
25
30
35
1xHSPA today 5xHSPA+ 5xHSPA + 2x20
MHz LTE
Millions
Macro Cell Capacity Limits – Subscribers
• Each subscriber with 1 GB/month
31 M subs á 1 GB/month,
or 3.1 M subs á 10
GB/month. That is 10
GB/month for every single
Elisa subscriber!

0
1000
2000
3000
4000
5000
6000
7000
8000
Elisa Typical European
operator
Claro Argentina Comcel Colombia
Voice
subs/site
But Some Countries will hit Shannon Limit This
Year – Example Latin America
Low number of sites
No new 3G spectrum
x
3G air interface will be
major bottleneck!
=
• 3G deployed by refarming into
existing 850/1900 which is already full
of GSM voice
• AWS spectrum will be available in
Chile 2009 – other countries not clear
• 700 broadband spectrum availability
not clear

HSDPA (+2G) Usage Growth in Finland
• The total data volume growth 3.4x during 1H/2008 and 2.1x during
2H/2008. The annual growth was 7.3x.
• The usage per sub per month grew from 460 MB during 2H/2007, to 730
MB in 1H/2008 and 1000 MB in 2H/2008.

Voice (VoIP) in LTE

Voice is Still Important in LTE
Paging in
LTE
2G/3G RAN
MME
E-UTRAN
MSC-S MGW
CS call setup
in 2G/3G
CS Fallback handover
• Voice with LTE terminals has a few different solutions
• The first voice solution in LTE can rely on CS fallback handover where
LTE terminal will be moved to 2G/3G to make CS call
• The ultimate LTE voice solution will be VoIP + IMS
• CS voice call will not be possible in LTE since there is no CS core
interface

Single Radio Voice Call Continuity (SR-VCC)
LTE VoIP
3G CS voice
LTE VoIP
3G CS voice 3G CS voice 3G CS voice
Single Radio Voice Call
Continuity (SR-VCC)
• Options for voice call continuity when running out of LTE coverage
• 1) Handover from LTE VoIP to 3G CS voice
– Voice handover from LTE VoIP to WCDMA CS voice is called SR-VCC
– No VoIP needed in 3G
• 2) Handover from LTE VoIP to 3G VoIP
– VoIP support implemented in 3G

Fast Track to LTE VoIP (VoLTE)
Primary Voice service to MSC Server with IMS-ready upgrade
A simple software upgrade to an MSS system to provide carrier-grade VoIP service
and interoperability with current 2G and 3G networks.
Broadband LTE
introduction
MGW MSS
LTE
HSPA & I-HSPA
2G/3G
CS/PS
Increased radio
efficiency for voice
service
LTE
HSPA & I-HSPA
2G/3G
Full IMS centric
multimedia service
architecture
LTE
HSPA & I-HSPA
PS
Evolution
to
IMS
VoIP
solution
Introduce
NVS
VoIP
solution
NVS
IMS
MGW MSS NVS
CS/PS
Data only LTE Fast track LTE VoIP Fast IMS multimedia

0
5
10
15
20
25
30
35
40
45
50
GSM EFR GSM
AMR
GSM
DFCA
WCDMA
CS voice
5.9 kbps
HSPA
VoIP/CS
12.2 kbps
HSPA CS
5.9 kbps
LTE VoIP
12.2 kbps
User
per
MHz
Voice Spectral Efficiency Evolution from GSM to
LTE
• 15 x more users per MHz with 3GPP LTE than with GSM EFR!

Quality of Service (QoS) Differentiation

• For every EPS bearer the following QoS parameters are available
– QoS Class Identifier (QCI)
– Allocation Retention Priority (ARP)
– Aggregate Maximum Bit Rate (AMBR) (for all bearers together for one terminal)
• Additionally, for Guaranteed Bit Rate (GBR) bearers
– Guaranteed Bit Rate (GBR)
– Maximum Bit Rate (MBR) – but not part of Release 8
EPS Bearer Attributes
EPS=Evolved Packet System

LTE QoS Profiles
• A single scalar parameter (QoS Class Indentifier
=QCI) is a pointer to a set of QoS parameters
• QCI is called Label in LTE
• Simplified approach compared to 2G/3G where
each parameter is indicated separately
3G LTE/SAE
Residual BER
SDU error rate
Delivery of
erroneous SDUs
Max SDU size
Delivery order
Transfer delay
ARP
Traffic class
Traffic handling
priority
Max bit rate
Guaranteed bit
rate
QCI (QoS Class
Identifier)
ARP
Max bit rate
Guaranteed bit
rate
Aggregate max
bit rate
Per bearer
Per terminal

QoS Class Indentifier (QCI) Table in 3GPP
GBR
1
Guarantee
Delay
budget
Loss rate Application
QCI
GBR
100 ms 1e-2 VoIP
2
GBR
150 ms 1e-3 Video call
3
GBR
300 ms 1e-6 Streaming
4
Non-GBR 100 ms 1e-6 IMS signalling
5
Non-GBR 100 ms 1e-3 Interactive gaming
6
Non-GBR 300 ms 1e-6
TCP protocols :
browsing, email, file
download
7
Non-GBR 300 ms 1e-6
8
Non-GBR 300 ms 1e-6
9
Priori
ty
2
4
5
1
7
6
8
9
50 ms 1e-3 Real time gaming
3
• Operators can define more QCIs
• Several bearers can be aggregated together if they have the same QCI

Network Initiated Bearer in LTE
UE
SGSN
UE
SGSN
UE
MME
UE
MME
3G UTRAN LTE E-UTRAN
= Non-GBR bearer
for IMS signalling
= UE initiated GBR
bearer (VoIP)
= Network initiated
GBR bearer (VoIP)
• Guaranteed bit rate QoS requires its own bearer (PDP context)
• New bearer must be initiated by UE in 3GP
• New bearer can be initiated by network in LTE ⇒ less requirements for
the terminal and better network control
IMS VoIP IMS VoIP

LTE UE Connection Management Overview

LTE Radio Resource Control (RRC) States
RRC Connected State
• UE location is known in MME
with an accuracy of a cell ID
• The mobility of UE is handled by
the handover procedure
• The UE performs the tracking
area update procedure
• A signalling connection exists
between UE and MME
RRC Idle state
• No signalling connection
between UE and network exists
• No UE context exists in E-
UTRAN
• UE performs cell reselections
• Paging needed when the there is
data in downlink direction
• RACH procedure used on
establish RRC connection
RRC
connection S1 connection
Handovers
MME
LTE
UE

LTE UE RRC Connection Maintenance
• UE’s RRC connection can be maintained even if UE is
inactive
• RRC connection may be released due to the following
reasons
inactive >x min
2. High mobility: UE makes x
handovers within m minutes
1. UE is inactive for a long
time
3. Max number of RRC
connected UEs reached.
Release longest inactive UE.

LTE Tracking Area
Tracking area 1 Tracking area 2
Tracking area update
MME
• Tracking area (TA) is similar to Location/routing area in 2G/3G
• Tracking Area Identity = MCC (Mobile Country Code), MNC (Mobile
Network Code) and TAC (Tracking Area Code)
• When UE is in Idle, MME knows UE location with Tracking Area accuracy

LTE Handovers

LTE Handover Principles
• Lossless
– Packets are forwarded from the source to the target
• Network-controlled
– Target cell is selected by the network, not by the UE
– Handover control in E-UTRAN (not in packet core)
• UE-assisted
– Measurements are made and reported by the UE to the network
• Late path switch
– Only once the handover is successful, the packet core is involved

Handover Procedure
SAE GW
MME
Source
eNB
Target
eNB
SAE GW
MME
SAE GW
MME
SAE GW
MME
= Data in radio
= Signalling in radio
= GTP tunnel
= GTP signalling
= S1 signalling
= X2 signalling
Before handover
Handover
preparation
Radio handover
Late path
switching

User Plane Switching in Handover
UL DL
UL
DL
UL
DL
DL
UL
DL
DL
UL
Before handover
Packet
forwarding
Late path
switching
UL DL

Data Forwarding
• Data Forwarding between source and target eNB ensures lossless
operation
• Downlink
– source eNB forwards all downlink RLC SDUs that have not been acknowledged
by the UE to the target eNB
– target eNB re-transmits and prioritize all downlink RLC SDUs forwarded by the
source eNB as soon as it obtains them
– reordering and duplication avoidance in the UE
• Uplink
– source eNB forwards all successfully received uplink RLC SDUs to the EPC
– UE re-transmits the uplink RLC SDUs that have not been successfully received
by the source eNB
– Reordering and duplication avoidance in EPC

Handover Preparation
UE Source Target MME GW
1. Measurement
control
2. Measurement
report
3. HO
decision
4. HO request
5. Admission
control
6. HO request ack
• 1. The source eNB configures the UE
measurement procedures with
MEASUREMENT CONTROL
• 2. UE is triggered to send
MEASUREMENT REPORT to the
source eNB. It can be event triggered
or periodic
• 3. Source eNB makes handover
decision based on UE report + load
and service information
• 4. The source eNB issues a
HANDOVER REQUEST to the target
eNB
• 5. Target eNB performs admission
control
• 6. Target eNB sends the HANDOVER
REQUEST ACKNOWLEDGE to the
source eNB

Handover Execution
7. HO command
8. Status transfer
Forward
packets to
target
Buffer
packets
from
source
9. Synchronization
10. UL allocation and timing
advance
11. Handover
confirm
• 7. Source eNB generates the
HANDOVER COMMAND towards UE
• Source eNB starts forwarding packets
to target eNB
• 8. Source eNB sends status
information to target eNB
• 9. UE performs the final
synchronisation to target eNB and
accesses the cell via RACH procedure
– DL pre-synchronisation is obtained
during cell identification and
measurements
• 10. Target eNB gives the uplink
allocation and timing advance
information
• 11. UE sends HANDOVER CONFIRM
to target eNB
• Target eNB can begin to send data to
UE

Handover Completion
12. Path switch
request
13. User plane update
request 14.
Switch
downlink
path
15. User plane update
response
16. Path switch request
ack
17. Release resources
18.
Release
resources
• 12. Target eNB sends a PATH SWITCH
message to MME to inform that the UE
has changed cell
• 13. MME sends a USER PLANE
UPDATE REQUEST message to Serving
Gateway.
• 14. Serving Gateway switches the
downlink data path to the target side
• 15. Serving Gateway sends a USER
PLANE UPDATE RESPONSE message
to MME.
• 16. MME confirms the PATH SWITCH
message with the PATH SWITCH ACK
message.
• 17. By sending RELEASE RESOURCE
the target eNB informs success of
handover to source eNB and triggers the
release of resources.
• 18. Upon reception of the RELEASE
RESOURCE message, the source eNB
can release radio and C-plane related
resources associated to the UE context.

Handover Measurement Procedure
1. eNodeB sends Measurement control to UE giving Reporting
thresholds
2. UE identifies others cell ids from Synchronization signal
• See earlier slides on the cell search procedure
3. UE measures other cells’ signal from Reference Symbols
(RS)
• No need to read Broadcast channel (PBCH)
4. When the reporting threshold condition is fulfilled, UE sends
Handover measurements to eNodeB
• See earlier slides on the measurements

Neighborlist Generation in LTE
• LTE UE can detect the intra-frequency neighbors without
neighborlists ⇒ simpler network management
• UE reports other cell ids to eNodeB
• If the target cell id is known by eNodeB, it will proceed with
the handover.
• If the target is not known by eNodeB and no is X2 enabled,
1. eNodeB asks UE to decode Global cell id of the target cell
2. eNodeB finds out the target cell’s IP address from O&M
3. eNodeB enables X2 connection to the target cell
4. eNodeB proceeds with the handover
• 2G network operators need to define the neighborlists
• Also 3G network operators need to define the neighborlists
but it is possible for UE to detect the new cells outside
neighborlist which makes neighborlist creation simpler.

Terminology in LTE and in 3G
– Connection and Mobility Management
3G LTE
PDP context EPS bearer
Location area Not relevant (no CS core)
Routing area Tracking area
Radio access bearer Radio bearer + S1 bearer
GPRS attached EMM registered
Handovers (DCH) and cell
reselections (PCH) when RRC
connected
Handovers when RRC
connected
RNC hides mobility from
core network
Core network sees every
handover
Connection management
Mobility management

LTE Frequency Variants

3GPP Supported FDD Frequency Bands
1
2
3
4
5
7
8
9
6
2x25
2x75
2x60
2x60
2x70
2x45
2x35
2x35
2x10
824-849
1710-1785
1850-1910
1920-1980
2500-2570
1710-1755
880-915
1749.9-1784.9
830-840
Total [MHz] Uplink [MHz]
869-894
1805-1880
1930-1990
2110-2170
2620-2690
2110-2155
925-960
1844.9-1879.9
875-885
Downlink [MHz]
10 2x60 1710-1770 2110-2170
11 2x25 1427.9-1452.9 1475.9-1500.9
1800
2600
900
US AWS
UMTS core
US PCS
US 850
Japan 800
Japan 1700
Japan 1500
Extended AWS
Europe Japan Americas
788-798 758-768
777-787 746-756 US700
2x10
2x10
13
12 2x18 698-716 728-746
14
704-716 734-746
2x12
17
US700
US700
UHF (TV)
815-830 860-875
2x15
18
US700
830-845 875-890
2x15
19
832-862 790-820
2x30?
xx
Japan new 800
Japan new 800

Region
3GPP Supported TDD Frequency Bands
Operating
band
Total
spectrum
Frequencies [MHz]
Rel-8
Band 39
Band 40
40 MHz
100 MHz
1880-1920
2300-2400
Rel-7
Band 38 50 MHz 2570-2620
Rel-99ÆRel-6
Band 33
Band 34
Band 35
Band 36
Band 37 20 MHz
60 MHz
15 MHz
20 MHz
60 MHz
1910-1930
1850-1910
2010-2025
1900-1920
1930-1990
1
2
Note:
*1 IMT2000 Frequency. Generally in EU and China
*2 IMT2000 Frequency. Used in China
*3 TDD bands allocated in USA/Canada as part of technology agnostic approach in PCS bands.
Current commercial deployments in these bands are FDD
*4 Operating band numbers are for LTE TDD from TS 36.104, different numbering scheme in
WCDMA TS 25.105
Ref: 3GPP TS 36.104
3
3
3
4
Rel-9
Band ??
Band ??
200 MHz
200 MHz
3400-3600 ?
3600-3800 ?
3.5 GHz
bands under
study

TDD Spectrum Allocation in China
• Total of 155 MHz allocated to TDD
• TD-SCDMA deployment with limited rollout in TDD2 band (10 cities)
• Next step geographically expansion in TDD2 band
• Next TD-SCDMA spectrum expected to be TDD1 band (PHS switch-off after
telecom reorganization)
• CMCC envisages 2.3GHz TDD3 band for TD-LTE (100 MHz BW)
• Current national 3G telecommunication strategy
CMCC Ö TD-SCDMA
CT Ö EV-DO
CU Ö WCDMA/HSPA
TD-SCDMA
rollout TD-LTE
40 MHz 15 MHz 100 MHz

First 2.6 GHz Auctions – Norway and Sweden
• Norway (29 M€)
– Telenor 2x40 MHz
– Teliasonera 2x20 MHz
– Hafslund 2x10 MHz
– Craig Wireless 1x50 MHz
Telenor UL Telenor DL
Netcom
UL
Netcom
DL
Craig Wireless TDD
Hafslund TDD Hafslund TDD
• Sweden (225 M€)
– Telenor 2x20 MHz
– Teliasonera 2x20 MHz
– Tele2 2x20 MHz
– HI3G 2x10 MHz
– Intel 1x50 MHz
Norway allocation

ECC SE42 (CEPT Report 019) applied to
2.6 GHz ECC band plan
TDD
2570
Restricted block, max TDD
EIRP=25 dBm / 5 MHz ⇒
Pico / Femto BTS
FDD
FDD
2570 2575
2620
40 MHz
2500 2690
Potential FDD to TDD
interference
2615 2620

US 700 MHz Auction March 2008
• Frequency variants Band 12, 13 and 14 cover 700 MHz
• Band 12 covers lower A, B and C blocks (mostly AT&T)
• Band 13 covers upper C block (mostly Verizon)
• New band 17 will cover just lower A and B blocks for AT&T
B C D E A B C C A D
Saf
ety
C A
B D
Saf
ety
B
698 MHz 746 MHz 806 MHz
A
Band 12
Uplink
Band 12
Downlink
Band
13 DL
Band
13 UL
Band
14 DL
Band
14 DL
Blocks A and B
and lower C
Block C

LTE 5 MHz in 900/1800 MHz Refarming
24 GSM carriers
GSM only operation in 5 MHz
LTE 3 MHz (2.8
MHz)
1.5 MHz
LTE 3 MHz in coordinated case
takes 14 GSM carriers
LTE
1.4
MHz
0.7 MHz
LTE 1.4 MHz in coordinated case
LTE 5 MHz (4.6 MHz)
2.5 MHz
LTE 5 MHz in coordinated case

Digital Dividend (UHF – TV Bands) for LTE700
792 822 862
832
Downlink Uplink
• Total spectrum 790-862 MHz
• Enables 2x30 MHz FDD operation
• 3 operators, each having 10 MHz LTE FDD carrier
• Optimized spectrum for coverage LTE coverage

790-862 in Germany (March 4th)
Potentially available
already 2010

Spectrum Resources – Typical European Case
700
(10 MHz) LTE 10 MHz
900
(10 MHz) GSM 1xHSPA+ GSM
1800
(15 MHz) GSM LTE 15 MHz
2100
(15 MHz) 3xHSPA Multicarrier
HSPA
2600
(FDD 20 MHz) LTE 20 MHz
Current Future
LTE capacity and
high data rates
HSPA capacity
LTE capacity
HSPA coverage +
GSM maintenance
LTE coverage
• HSPA and LTE typically deployed at different frequencies

HSPA+ and LTE

3GPP LTE Downlink Spectral Efficiency Summary
0.0
0.5
1.0
1.5
2.0
2.5
UTRA baseline E-UTRA 2x2
bps/Hz/cell
Alcatel-Lucent
Ericsson
Huawei
InterDigital
Motorola
NEC
Nortel
Nokia-Siemens
Qualcomm
Samsung
Texax Instruments
Average
HSPA
0.55 bps
LTE 1.7
bps
• Downlink spectral efficiency shown to be 3 x HSPA R6 (=UTRA
baseline), which was the target of LTE

3GPP LTE Uplink Spectral Efficiency Summary
• Uplink spectral efficiency shown to be >2 x HSPA R6, which was the
target of LTE
0.0
0.2
0.4
0.6
0.8
1.0
1.2
UTRA baseline E-UTRA 1x2
bps/Hz/cell
Alcatel-Lucent
Ericsson
Huawei
InterDigital
Motorola
NEC
Nortel
Nokia-Siemens
Qualcomm
Samsung
Texax Instruments
Average
HSPA
0.33 bps
LTE 0.75
bps

Key Features for LTE Downlink Spectral Efficiency
Compared to HSPA R6
Inter-cell interference rejection
combining or cancellation
MIMO = combined use of 2 tx and 2 rx
antennas
Frequency domain packet scheduling
+10%
+20%
+40%
Total gain up to 3.1x
OFDM with frequency domain
equalization +20..70%
Compared to single antenna BTS
tx and 2-rx terminal
Not feasible in HSPA due to
cdma modulation
Possible also in HSPA but better
performance in OFDM solution
Due to orthogonality
• 3GPP R7/R8 brings equalizer, MIMO and frequency domain scheduling
to HSPA

HSPA Data Rate Evolution
14 Mbps
21-28
Mbps
Downlink
3GPP R5
3GPP R6
3GPP R7
Uplink
42 Mbps
84 Mbps
3GPP R8
3GPP R9
168 Mbps
3GPP R10+
14 Mbps
0.4 Mbps
5.8 Mbps
11 Mbps
11 Mbps
23 Mbps
54 Mbps
DC-HSDPA
DC-HSDPA
+ MIMO
4-carrier
HSDPA
DC-HSUPA
4-carrier
HSUPA
16QAM
64QAM or
MIMO
• HSPA has strong data rate evolution beyond 100 Mbps making HSPA
competitive long term solution for broadband data

Spectral Efficiency Evolution
Evolution of HSPA efficiency
0.55
1.06 1.11
1.31
1.44 1.52
1.74
0.33 0.33 0.33
0.53
0.65 0.65
0.79
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
HSPA
R6
HSPA
R6
+
UE
equalizer
HSPA
R7
64QAM
HSPA
R8
DC-
HSDPA
+
3i,
UL
IC
HSPA
R9
DC-
HSDPA+MIMO,
UL
progressive
PC
HSPA
R10
QC-
HSDPA+MIMO
LTE
R8
bps/Hz/cell
Downlink
Uplink

HSPA Evolution Matching LTE Requirements
[LTE Requirements in 3GPP 25.913]
Peak rate downlink 100 Mbps 168 Mbps
3GPP LTE requirements HSPA+ capability
Peak rate uplink 50 Mbps 54 Mbps
Spectral efficiency
downlink 3xHSPA R6 3xHSPA R6
Spectral efficiency uplink 2xHSPA R6 2xHSPA R6
1-way user plane latency <5 ms 3.6-4.9 ms incl. 10%
retransmit
Control plane latency <50 ms <50 ms
Enhanced MBMS 1 bps/Hz >1 bps/Hz
Spectrum flexibility 1.4-20 MHz 4.2-20 MHz
Architecture Minimized interfaces 2 element user plane
• HSPA can fulfill all LTE requirements – except for <4 MHz and TDD.
• All these features supported by Flexi FSME system module
Duplexing Harmonized FDD and TDD FDD only

Harmonization of HSPA and LTE
• HSPA and LTE have been developed by the same
standardization organization. The target has been
simple multimode implementation.
• HSPA and LTE have in common
– Sampling rate using the same clocking frequency
– Same kind of Turbo coding (also maximum block size close
enough)
• The harmonization of these parameters is important
as sampling and Turbo decoding are typically done
on HW due to high processing requirements

Broadband Wireless Status

HSDPA Data Growth Exceeded Expectations
10 TB/day
20 TB/day
Different colors = different operators
• HSDPA usage tens of TB/day and busy hour throughput several Gbps
• HSDPA traffic has increased 4-5 times within 12 months = 3% per week
Example busy site in live network
• >40.000 AMR calls per day
• >100 simultaneous AMR calls
• >160.000 HSDPA calls per day
• >50 GB data per day
• >10 Mbps busy hour throughput

HSPA Broadband Penetration Hitting 10% of
Population in Advanced Markets
USB modem
penetration from 2%
to 7% in 12 months in
Sweden (mid-2008)
HSPA penetration of population – 3Q/2008

HSDPA Penetration Growth in Finland
• HSDPA penetration has increased from zero to 9% within 1.5 years. The
penetration is here defined relative to the total population of 5.36M.
• HSDPA makes 23% of all broadband connections
• Source: http://www.ficora.fi/attachments/5fgEgJfk4/mk08_36s_a4_08_090330.pdf

DSL Penetration Has Dropped in Some HSDPA
Markets
-2%
0%
2%
4%
6%
8%
10%
12%
14%
R
o
m
a
n
i
a
B
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i
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H
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a
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y
S
p
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a
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P
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a
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U
K
L
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l
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c
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R
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A
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t
r
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l
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F
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d
DSL subscriber growth, 1Q 2008 - 2Q 2008 [Source: Analysys Mason, 2008]
DSL penetration has
decreased in countries with
high HSDPA penetration
DSL subscriber growth, 1Q 2008 - 2Q 2008 [Source: Analysys Mason, 2008]

LTE-Advanced

LTE-Advanced (LTE-A) in 3GPP Release 10
• ITU has defined schedule for IMT-Advanced (IMT-A) with
submission deadline October 2009
• Local area data rate up to 1 Gbps and wide area 100 Mbps
• 1st technical 3GPP workshop in April 2008
– Until end of 2008 the clear focus was on LTE Release 8
– The same multiple access to be used also in LTE-Advanced as in LTE
– 3GPP during 2009 to work with the LTE-Advanced study item, no
specifications to be developed until 2H/2010 (technical report in 2009)
2011
3GPP
2007 2008 2009 2010
1st Workshop
Study Item
Start
Technology
Submissions
Specification
Created
ITU-R
Circular
Letter
Close Study &
Start Work Item
Evaluation
Process
Specification
Created

LTE-Advanced technologies:
• The following topics are being worked with*
– Wider bandwidth support (up to 100 MHz)
– Uplink MIMO (2 TX antennas in UE), also further DL MIMO (8-by-X)
ƒ Uplink multiple access stays unchanged as decided in Jan 2009
ƒ Also with 2 antenna TX SC-FDMA to be used
– Co-ordinated multipoint transmission (CoMP)
ƒ Receiving transmission from multiple sectors (not necessary visible for UE)
Rel’8
100 MHz bandwidth
Rel’8 Rel’8 Rel’8 Rel’8
Release 10 LTE-Advanced UE resource pool
Release 8 UE uses a
single 20 MHz block
20 MHz
* 3GPP TR 36.814

LTE-Advanced Technologies: Relays
• The use of Relays attracts a lot
of interest in 3GPP
• The existing specification
allows use of MBSFN sub-
frames
– Release 8 devices are not
expecting transmission in MBSFN
sub-frame (and during which relays
can be provided with data)
• Backhaul for relay can be in-
band or out-band
Data
Ctrl
transmission gap
(“MBSFN subframe”)
Ctrl
One subframe
No relay-to-UE transmission
eNB-to-relay transmission
relay link access
link
direct link

0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
HSPA R6 HSPA R10
QC+MIMO
LTE R8
2x2 MIMO
LTE R8
4x4 MIMO
LTE-A R10
2x2 MIMO
LTE-A R10
4x4 MIMO
bps/Hz/cell
Downlink
Uplink
Spectral Efficiency Improves but Only Moderately
• Shannon law limits link performance improvements
• Only moderate gain in spectral efficiency
HSPA
LTE
LTE-A

Technology Evolution
42-168
Mbps
1.21-1.91
bps/Hz/cell
162 dB
HSPA+
150-300
Mbps
1.7-2.71
bps/Hz/cell
162 dB
LTE
1 Gbps
2.4-3.71
bps/Hz/cell
-
LTE-A targets
14-rx mobile
7-14 Mbps
1.0
bps/Hz/cell
162 dB
HSPA
70-150x
2-4x
~1x
• Peak bit rate increases by a factor of 100x
• Spectral efficiency increases by a factor of 3x (=interference limitation)
• No substantial improvements in coverage (=noise limitation)
New radio solution needed to improve coverage and capacity
⇒ active antennas, high density of small BTS, C-MIMO and relaying
Peak bit
rate
Spectral
efficiency
Coverage
(1 Mbps)

Abbreviations
• AMR = Adaptive Multirate
• ARP = Allocation and Retention priority
• aSN-GW = Access service note gateway
• AWGN = Additive white Gaussian noise
• BCH = Broadcast Channel
• CDG = CDMA development group
• CM = Cubic metric
• CPE = Customer premise equipment
• CS = Circuit switched
• CQI = Channel quality information
• DCH = Dedicated Channel
• DL = Downlink
• DL- SCH = Downlink shared Channel
• DRX = Discontinuous reception
• DTX = Discontinuous transmission
• eNB = eNode B
• ECM = EPS connection management
• EMM = EPS mobility management
• EPC = Evolved packet core
• EPS = Evolved packet system
• FCC = Federal communication commission
• FDD = Frequency division duplex
• FFT = Fast Fourier Transform
• GBR = Guaranteed bit rate
• HARQ = Hybrid automatic repeat request
• HO = Handover
• HSPA = High speed packet access
• HSDPA = High Speed downlink packet access
• HSUPA = High speed uplink packet access
• HS-PDSCH = High Speed Physical Downlink Shared Channel
• ICIC = Inter-cell interference coordination
• IETF = Internet engineering task force
• ILBC = Internet low bit rate codec
• LTE = Long term evolution
• MBR = Maximum bit rate
• MCC = Mobile country code
• MCH = Multicast Channel (MCH)
• MIMO = Multiple Input Multiple Output
• MNC = Mobile network code
• MME = Mobile management entity
• NAS = Non-access stratum
• OFDMA = Orthogonal Frequency Division Multiple Access
• PBCH = Physical Broadcast Channel
• PCH = Paging Channel
• PCS = Personal communication service
• PCFICH = Physical Control Format Indicator Channel
• PDSCH = Physical Downlink Shared Channel
• PDCCH = Physical Downlink Control Channel
• PRACH = Physical Random Access Channel
• PMCH = Physical Multicast Channel, PMCH
• PHICH = Physical Hybrid ARQ Indicator Channel
• PUCCH = Physical Uplink Control Channel
• PUSCH = Physical Uplink Shared Channel,
• QCI = QoS class identifier
• QoS = Quality of Service
• RACH = Random acccess channel
• RLC = Radio link control
• RRC = Radio resource control
• RSSI = Received signal strength indicator
• SC-FDMA = Single Carrier Frequency Division Multiple Access
• SDU = Service data unit
• SR-VCC = Single radio voice call continuity
• TA = Tracking Area
• TAC = Tracking Area Code
• TDD = Time division duplex
• TSG = Technical specification group
• UE = User equipment
• UL = Uplink
• UL-SCH = Uplink Shared Channel
• UMTS = Universal mobile telecommunication system
• VoIP = Voice over IP
• WCDMA= Wideband code division multiple access
• WiMAX = Worldwide interoperability for microwave access

Annex: 1
3GPP LTE Release 9 work/study items
(Following TSG RAN Plenary 03/2009, next plenary end of
May, 2009)

Huawei
Ericsson
RF requirements for LTE pico NodeB
UMTS/LTE in 800 MHz for Europe
Raporteur
Title
True Position
Network-Based Positioning Support for LTE
CMCC
Enhanced DL Transmission for LTE
CMCC
LTE TDD Home eNodeB RF Requirements
Qualcomm
Positioning support for LTE
Motorola
LTE FDD Home eNodeB RF Requirements
Huawei
MBMS support in LTE
NSN
SON (for LTE)
ALU
Support of IMS emergency calls
*
Benefit/Notes
MIMO +
beamforming
For 1900-1920
MHz in Europe
DL methods
Self organizing
Networks
* Covers also HSPA -> trend that in many areas LTE and HSPA work done jointly!
NTT DoCoMo,
(NSN &
Ericsson)
LTE-Advanced
Study item,
specs in
Release 10
ALU
Support of HNB/HeNB enhancements RAN
3 aspects
Huawei
Support of HNB/HeNB enhancements RAN
2 aspects
*
*
Ericsson
RF Requirements for Multi-carrier and Multi
RAT BS Started in 2008*
Powerwave/Andrew
LTE FDD Repeaters
Ericsson
UMTS/LTE 3500 MHz Started in 2008*

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