LTE handover

A Novel Self-Organizing Network Algorithm
For Modeled HetNets LTE-Advanced Through
Hybrid Fractional Frequency Reuse (HFFR)
Scheme
Dissertation submitted in partial fulfillment of the requirement for the degree of
MASTER OF TECHNOLOGY
in
Computer Science & Engineering
Submitted by
Mona lamba
Reg. No.-09RITS1132
Roll No.-14M1A11
Under the Guidance of
Mr. MARENDER.DAGAR
Assistant Professor
Department of Computer Science & Engineering
Shri Ram College of Engineering and Management,
Palwal, Haryana

For More info Https://ThesisScientist.com
Chapter 1
INTRODUCTION
For developing to 4G mobile communications, the need to evolve the systems towards
giving support to a broader range of telecommunication uses, including multimedia
service, is increasingly obtaining significance. Consequently, ITU prolongs 4G technique
as IMT-Advanced, and exhibits high network convergence, data rate, ubiquitous and
continuous link as features. Successively, mobile operators now face the issue of
preserving these increasingly complex networks constitute of many Radio Access
Technologies (RATs), different cell types and subscribers with a variety of QoS
requirements. The earning of the mobile operators is, usually, degrading simultaneously.
Therefore, it is important that combining and operating novel and usable network nodes
require minimal manual efforts to control OPEX. Therefore, considerable industry
momentum has construct currently to set up Self-Organizing Network (SON)
characteristics that can manage mobile network deployment, operation and management.
Within the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE)
standardization, SON was among the early system requirements; SON characteristics were
included in the first 3GPP LTE Release..
1.1 3G LTE network structure
SON works in 3GPP has been inspired by sufficient by SON studies and the set of
requirements explained by the operators‘ bond, Next Generation Mobile Network. As a
technique which satisfies above specified conditions, LTE -Advanced is in the
significance now. As indicated in Fig 1, 3G LTE uses backbone relied on ALL-IP,
interworking with different networks continuously. The service stipulate from 3GPP LTE-
Advanced is always joined with data rate of over greater 100Mbps and lower delay; it is
feasible to continuously interwork with sufficient facilities in HSDPA and WCDMA
networks. In case of choosing 3GPP LTE-Advanced, it is possible to link obtainable 4G
and 3G networks, so all of transmission services could be used with only one mobile

terminal. The most unusual process for this is service continuity technique by seamless
link. LTE-Advanced should provide high-speed data transmission primarily in hot-spot
space, and gives service continuity during session movement and movement terminal with
only a mobile terminal. Since, in LTE-Advanced where many networks usable, it is
actually complex to give service continuity essentially. And due to every resource in LTE-
Advanced system and the network state i.e. bandwidth, error rate replace variably, it is
assumed that it is not possible to manage service continuity with artificial, procedural, and
static management method employed to the usable voice service. As a solution for this, we
suggest a self-organizing network (SON) concept in LTE-Advanced. it is targeted at
constructing heterogeneous networks spread more stably and efficiently through
employing self-organization concept that different networks unite and act each other for
better impact, so that it has got a lot of care as core technology to hire commercial system
of future mobile communication networks after 4G as well as LTE-Advanced. As of yet, it
generally concentrates on growth of physical aspect i.e. performance enhancement,
establishing base stations and ability expansion, but it is seen that if a mechanism which
assures service continuity relied on self-monitoring process is developed, it will play a
important role in market expansion of LTE-Advanced; self-monitoring is a technique for
performing traffic management and improving resource ability by examining some
surrounding information about neighboring terminals and cells, which is the central
technology of SON.
Figure 1.1 3G LTE network structure

We recommend a service self-organization technique to sustain the service continuity
effectively depending on SON, in which a mobile terminal collects some news about its
current state of every cell and a base station, depending on the news collected by
maintaining inner or neighbouring cells, managing service continuity on its own and
distributes related data and converges. In other words, related news of cells and mobile
terminals changes, the operation of context functions i.e. cell selection, ISHO, load
management, source assignment and QoS mapping is followed; every function is
appropriate into the change, exchanges the phenomenon of reorganization, and interacts;
these activities go toward to satisfy service continuity.
In current literature, SON has been exhibited. SON associates to Minimization of Drive
Tests (MDT). An essential driver for mobile operators implementing SON is to diminish
OPEX and CAPEX in all phases of the network engineering life cycle: planning,
deployment, and operation. The SON characteristics also targeted to enhance network
performance. The use of SON is essential, if not predictable, for most operators operating
multi- vendor, multi-RAT and multi-layer networks in which an overloading no. of
features has to be gathered and analyzed. For SON to be desirable to mobile operators, its
advantages, included both performance improvement and OPEX/CAPEX degradation,
should exceed in weight the cost to implement and to preserve SON-related services.
Towards this aim, operators have a no. of high-level goals for every phase of the network
engineering life cycle:
1 Planning of current sites (or extension of available ones) should be as simple, time- and
cost effective as possible, lead to the less no. of sites (or the most cost-efficient
deployment) for a needed performance, and relied on sufficiently right news.
2 Deployment of new sites should be as simple as possible with the less cost and effort—
i.e, ―plug and play‖—and with no interoperability problems.
3 Operation of the network(s) should also be as simple as possible with the less cost and
attempt, allow for fast and effective identification of an issue and its reason, suggest
immediate (and preferably automatic) reaction to aspects (for example, self-optimization
and self-healing), and conclude the best possible performance and optimum use of the
deployed resources. A brief of SON services and where they are sufficient in the network

engineering life cycle is overviewed in Fig. 1. This fig shows that operational
effectiveness for mobile operators is needed to enhance as current SON characteristics
become existed. By operational effectiveness, we mean effectiveness in endeavor and cost
spent in deployment, planning and operation, as well as network achievement. This article
gives a summary of SON 3GPP standardization, including its relation to MDT and its
needed usage in the three network engineering phases. First, usable SON solutions in
3GPP (up to Release 11, ended in early 2013) are described. Following that a brief of
ongoing SON standardization (such as Release 12, need to be accomplished at the end of
2014) and a future vision for SON is given. At last, we give a point of view on how these
solutions are associate to mobile operators, including potential issues.
Figure 1.2: SON Algorithm
3GPP is an organization for standardizing LTE which is known as 3.9th generation with
GSM, HSDPA, WCDMA hired by new 89% of mobile communication users. It has been
execute the standardization of LTE-Advanced for satisfying the system requirement of
IMT-Advanced by complement of LTE technology. Though it is complex to expect that
LTE-Advanced is more developed in epochal technology in comparation of LTE, it is
recommended to be improved in the area of broadband support, network cooperative

communication, many antenna spread, SON technology. The examiner on the idea of
common radio resource administration, whose goal is to keep up every access network in a
synthetic way to provide ISHO function and to evaluate the achievement in many
heterogeneous access networks, is being conducted actively. Particularly, 3GPP gives a
network structure for combined radio resources management in TR25.881 the technique
standard text and common radio resource management (CRRM) the mechanism of the
combined radio resources management to support that, and many projects to modify and
complement the weak point of CRRM are being recommended.
1.2 Aim and Objectives:
The important goal of this thesis is represented as demonstrating a self-organising based
process for current versions of heterogeneous LTE-Advanced networks to simultaneously
improve both quality of service and ability. The main index terms of this research could be
exhibited as: SON; LTE-A, HetNets; Femtocell; Interference, Multi-Layer; Handover,
Access Control; Power Control, eICIC. The self-organising method of this research is
described as the primary goal, to be got through the following targets:
1. The first objective of the thesis condensed on coordinated resource assignment by
usage self-organising schemes. The efficient frequency reuse is recommended among
femto and macro sub-networks, to hire bandwidth optimisation for diverse access
cellular networks. The current dynamic bandwidth provides method is designed over
a unique algorithm to hire resource assignment for many base stations, by allotting
the complete accessible spectrum. The involved resource optimisation mechanism
enhances network throughput and diminishes network complexity, while preserving
a essential fraction of the existed resources within the complete network.
2. The second goal is to assure the mobility management requirements within the
coordinated LTE-A network. This objective is approached by recommending of a
recently made handover algorithm, which exploits the usable network mobility
features.
3. The third goal of this research stately concentrates on inter-cell interference mitigation
reling on power control mechanisms. The improved inter-cell interference coordination
(eICIC) algorithm is planned relied on downlink power reaction among femto and macro

sub-networks. To accomplish this goal, self-organising power association is suggested to
be deployed between femto stations. The new eICIC algorithm diminishes the complete
interference, as well as increasing the victim mobile subscribers‘ achievement, by
following network sending power.
1.3 Methodology of Thesis.
The need of hardware implementation and disbursement is enhancing by cellular network
developments. This thing has been the greatest motivation for this thesis to stress self-
organising answers for this sub-systems association matters in LTE-Advanced. The
hierarchical SON style in this work begins from the channel distribution objections as the
first challenge, goes toward the mobility management objections for the mobile nodes, and
ended by the interference management resolution., Each of the recommended issues are
introduced and talked about in detail in this thesis work, to take by the formulation of
problem and answer inside the offered chapters. This research relied on network
simulations, as well as a literature survey about the obtainable research work to figure out
the delivered novelty, in contrasts of the decided essential works. In spite of, the analysis
and changes for the recommended novel algorithms are for different layers in the open
system interconnection (OSI) model, OPNET network simulator has been hired as the
most appropriate software for our simulation work.
The designing of appropriate algorithms for the aforesaid contributions at the first phase is
including the simulation-based experiments of this thesis. Subsequently, a no. of different
scenarios are planned and modeled relied on multi-layer network architecture. The built
scenarios in OPNET simulator have been obtained according to physical structure of LTE-
A and LTE networks, which are accompanied by extra configurations to determine many
network statistics
1.4 SON Characteristics
A .Self-Configuration: The starting configuration of network elements in a mobile
network is complexes by a greater no. of parameters supporting configuration manually is
complex and time consuming. This is a seen candidate for automation because network
nodes usually have common values for greater portions of the form settings. Self-

configuration network elements may be connected with a starting set of site-specific
features in an optional planning step. This assembling of features may be combined via the
3GPP automatic radio configuration data-handling function (ARCF), and may include pre-
configured neighbor relations, cell identities, transmit power levels, antenna
configurations, operational carrier, etc. The ARCF, along with any software upgrades, are
sent to the eNB in the self-configuration installation mechanism once the development of
connectivity is done. The eNB is operational after self-testing and prepared to support
mobile terminals.
B. Automatic Neighbor Relations (ANR): Ordinarily, a big optimization/configuration
cost for operators has been the handed creation of neighbor relations among cells. This is
based on the LTE ANR function placed in the eNB. It aids in administration of neighbor
cell relations within E-UTRAN, between UTRAN and EUTRAN and from E-UTRAN to
GERAN and CDMA2000 cells. An RNC or an eNB can demand a UE to decode
neighboring cell system news and appraise the decoded news back depending on the UE
ANR characteristic. Relied on this news, the eNB can search a unique cell identifier for
the neighboring cell. This shows that the supporting eNB has sufficient information to
begin a handover to the founded cell. Alternatively, the eNB may further utilize the
unmatched cell identifier to get connectivity news from the neighboring base station
through S1 eNB/MME optimization-transfer mechanisms and begins development of an
X2 interface. The evident advantage of ANR is that by using UEs to create and update
neighbor relations the whole procedure can be completed automatically. Giving the no. of
UEs in a network, this process is faster, more flexible and cost effective in comparation of
manual optimization or drive tests.
C. Automatic Cell Identity management: Mobility in 3GPP networks relied on UE
guided reporting of physical cell identifiers (PCIs) that rather should be temporary
unmatched. Matched PCIs can cause to confusion (a cell has two or more neighboring
cells with the identical cell identifier) or collision (neighboring cells have the identifier
cell identifier). PCI collision/confusion can be examined through the UE ANR
mechanism. The OAM system, observed of the examined PCI collision/confusion, can
begin a centralized PCI re-assignment procedure. This acquainted a new PCI to the cell
relied on the neighbor-relation news in the OAM system. Optionally, the OAM system

may give the eNB with a set of existed PCIs to select from, and authenticate the eNB to
select an optional PCI, in consideration of provided PCIs in environment eNB.
D. Random Access Optimization: The primary goal of the random access mechanism is
for UEs to notice their existence to the network and establish uplink time synchronization
with it. In the mechanism, the UE will select an access slot, a preamble waveform and a
transmission power. These features are subjected to optimization to satisfy requirements in
terms of:
• Access probability, which is the possibility of a UE having completed access after a
certain no. of random access trys.
• Access delay (AD) probability, where access delay is explained as the time duration for
a random access mechanism to complete once it is began by a UE.
To support RACH achievement estimation and optimization, the UE can be assisted to
give a RACH report to the eNB after a completed access attempt. This solution depends
on UE reports because the UE can control radio-related problems which the network may
not be known of. Hence, identical as the ANR function, this characteristic makes utilize of
UE reporting and monitoring capabilities.
E. Mobility Robustness Optimization (MRO): Robust mobility support is central to
mobile networks and MRO is an essential SON characteristic. MRO demands for intra-
LTE mobility are explained with respect to efficient mobility failure rates while neglecting
unimportant handovers as much as possible. The corresponding handover demands can
also be performed among any RAT or between any two RATs. The LTE MRO function
can be located in the eNB. The handovers are UE-guided, which signify that the UE is
optimized by its supporting eNB to forward a Measurement Report (MR) once a reporting
criterion is fulfilled. By getting a measurement report involving information about the
candidate cell triggering the report, the supporting eNB may start the handover mechanism
to the goal cell through S1 or X2 signaling. If the handover unsuccessful, the UE will
attempt to re-build the link to the radio access network or move to inactive mode and
rebind at a later step . Current additions to UE Radio Link Failure (RLF) reports in
Release 11 include feedback about the time elapsed since unsuccessful (such as for
dismissal of stale reports) and news and signaling to examine inter-RAT mobility failures.
Similarly, a handover (HO) report can be sent from a different RAT to E-UTRAN to

exhibit an unimportant inter-RAT HO. In such conditions, upon indication from the source
E-UTRAN and after a total handover, the goal RAT strengthens the UE with inter-RAT
cell measurements in the source RAT (E-UTRAN). If the coverage of one or more E
UTRAN cells is find out as acceptable for a certain time after the HO, then the inter-RAT
HO is supposed unimportant. The identical procedure allows E-UTRAN to configure a
timer in an aimed RAT to examine inter-RAT ping pongs. Especially, if an inter-RAT HO
towards E-UTRAN occurs within such a pre-described time window, the HO is supposed
―too early‖. The MRO answer integrates occurrences monitored by UEs which are not
showed directly from the network together with news from numerous eNB to examine the
primary reason of failure. Notices that from Release 10, MRO empower UE signaling of
RLF Reports after active-inactive transitions, which is specifically helpful in inter- RAT
mobility unsuccessful resolution.
1.5 MOBILITY LOAD BALANCING (MLB)
The aim of MLB is to control uneven traffic distributions, while diminishing the no. of
demanded HOs and redirections. The thresholds triggering which is an offloading action
can be enabled by general cell overload and connected load-performance indicators. By
the negligence of jeopardizing mobility robustness, the same goals are described for MRO
can also be supposed. The MLB service is in the eNB.
A difficulty with heterogeneous networks is that small cells may drag too small traffic,
which calls for macro cell offloading mechanism. Cell range expansion is one such
mechanism , where a Range Expansion Bias (REB) is taken for small cells when finding
measurement-report triggering standard for some or all UEs.
The compromise of the REB can be seen as mobility burden balancing. These adjustments
demand to consider UE-certain aspects i.e. detection capabilities and current traffic-
burden contributions due to the volatile act of interference in the range-expansion place. In
3GPP, eNB can allot resource status details through X2. Energy is an essential cost in
running mobile networks. The only standardized procedure to diminish energy
consumption is to inactivate cells that are locally not demanded. To give network energy
conserving, signaling support is explained among BSs as well as among RATs. If an eNB
has turned off a certain cell to diminish energy consumption, it may notice neighboring

eNB through a deactivation indication over X2. However, an eNB can demand a
neighboring eNB to re-activate a prior turned-off cell through a cell activation demand.
Release 11 has suggested some inter-RAT support, where it is possible to move cell
activation/deactivation details among RATs (for example UTRAN) through SON sending
messages. The latter technique diminishes complexity while managing interoperability.
1.6 SON For Release 12 And Beyond
Following the work done on SON and MDT in current 3GPP Releases, a new study item
to discover SON started in early 2013 and concluded in mid-2014. Specification work
initiated thereafter and is needed to finish by the last of 2014. In the following sections we
explain the Release 12 achievements further. Possible achievements beyond Release 12
are then also mentioned.
Release 12 SON: Current specifications make able mobility settings among various UEs
to be distinguished. The goal of the ―SON for UE types‖ task is to determine if such
differentiation can have a negative influence on interoperability. If this is so, then answers
to the interoperability issues are supposed. One aspect detected is the ping-pong handovers
caused by different mobility settings in neighboring cells.
Active Antenna Enhancements: Active antenna systems are one path to increase the
capacity of usable networks. The presently, comparatively fixed by deployments,
generally just joining vertical sectorization. Since, the technique does make able the
possibility of greater dynamic usage, involving cell shaping, UE-specific beam making,
and cell splitting and adding. The case where the no. of cells and the cell coverage modify
over time is explained in Figure 3. Such splitting and joining can be used to adapt system
capacity based on traffic conditions. It can be seen as a way to give more reliable
coverage/capacity management. Because, the capability to split and join cells dynamically
makes the actual management of these systems increasingly complex. With this keeping in
mind the work in Release 12 targeted at make able support for network deployments relied
on the generic characteristics of agile antennas. More certainly it studied whether usable
SON characteristics for deployment automation can be discovered to deal with dynamic
modify possible with active antennas i.e. cell splitting or joining. The primary
concentration on the study item associated to connection failures due to the cell splitting

and joining, as well as influence on MRO. The work will proceed with a Release 13
work item.
Pre-Release 12 Small Cells Enhancements — the term small cells globally mention low
power, operator-controlled, radio-access nodes. Small cells, which include Pico-, femto-,
metro- and micro-cells, have a range from tens to hundreds of meters. They are frequently
deployed by operators wherever extra capacity is needed. Certain SON functions for small
cells may diminish network planning efforts, enhance network optimization and address
issues and scenarios certain to small-cell deployment. Mobility strength is a challenge,
certainly because moving UEs may switch frequently among little cells. The involved
Release 12 improvements are designed to give the network extra details (such as further
RLF reports if failure occurs after re-establishment and UE time-to-trigger (TTT) details),
which can be used during MRO analysis so that better corrective events can be thought. In
addition to, OAM and S1-based answers have been involved to make easier inter-RAT
RLF reporting in ―LTE island coverage‖ scenarios where there is no LTE coverage
environment the small cells.
Multi-Vendor Network Element Plug and Play — The Release 12 work item deal with
scenarios where an eNB is joined to the protected operator network either through an
external network or a non-protected operator network. Server addresses needed for several
configurations are obtain through domain name servers.
1.7Operator Perspective On SON
The fad in network operations is to slowly go from ―semi-manual‖ toward autonomous
planning, deployment, and optimization. An open-loop or semi-manual operation means
that SON services suggested configurations which are initially sanctioned by the operator
before being strengthen. Autonomous network operation, also called closed-loop, intend
that sanctioned by the operator is neglected. Instead, the operator clearly explained high-
level performance objectives (in the form of a scheme) and monitors to what degree the
scheme is fulfill in the network.
In the planning phase, the DSS and CCO functions, with the help of MDT, can diminish
the operator‘s try in planning (i.e., decrease OPEX) and selecting optimum network
extensions (i.e., diminish CAPEX). Operators will still need a starting planning attempt to

deploy the coverage layer, but this attempt will diminish as the coverage layer is enlarged
(or completed) and has to be discovered with a capacity layer. It is required that the DSS
and CCO functions will be centralized and will generally work at the NM level. This is
due to the DSS and CCO analyze and optimize a cluster of BSs and the dynamics of the
recommended reconfigurations or extensions are comparatively slow such as up to less
reconfiguration per day or week for CCO or long-term extensions deployed over many
months for DSS. To include NM-centralized SON in the planning stage efficiently,
operators must address the following aspects:
1 Availability and accuracy of input data for proper NM-centralized SON decision-
making
Input data gives to NM-centralized SON functions may be in the form of KPI and MDT
reports/traces, improve with geographic coordinates. Collection of this data is given by
UE and eNB characteristics that are only optional. Due to this and the availability of
inherited BS s and UEs, the existence of input data may be neglected. A considerable
portion of input data may be given by vendor-proprietary answers.
2 Facilitating the collection and processing of data. Due to the large no. of base stations
and subscribers, as well as currently logging and reporting of associated details, a large
amount of data needed to be managed by the operator‘s network management system.
This requirement sufficient for Itf-N transport network capacity, processing capacity and
data storage capability for the NM-centralized SON algorithms.
3 Linking and synchronizing the NM-centralized SON functions with an operator’s
existing planning tools and Processes, as well as BSS/OSS systems. It is appropriate
that the identical, up-to-date input data is existed to all tools/processes involved in the
planning phase. Discrepancies in input data among different processes and tools at the
time of planning might consequence in sub-optimum configurations and network
unstableness.
1.8 PROPOSED SCHEME
If LTE-Advanced happens 4G-integrated standard, and a commercialization, service
givers which have many access networks, could associate a variety of access networks
relying on IP core network without another networks investment.

Figure 4: Two-layered control mechanism for service self-organization [2]
This thesis, with this industrial background, suggests a layered technique for giving
support to service continuity usage of SON, which is middle part for commercial system
use in LTE-advanced distributed networks. Fig 4 shows a two-layered management
method for the service of self-organization relied on SON.
1.9. Novel Research Contributions
This research involved, evaluates and suggests new self-organising network management
for HetNets LTE-A networks. The self-organisation methodology of this work is take
advantage by its different novel techniques to handle with bandwidth allocation, mobility
management and interference alleviation. The primary contribution chapters of this thesis
are presented on Figure 1-5. The self-organising strategy is determined as the primary
methodology of the work to help all the contributions. The novel techniques and their
important algorithms are mentioned and explained as follows:

Figure 1.5: Thesis main contributions on LTE-A system
Access Control: Sharing of the usable bandwidth using fixed frequency channels are
applied for heterogeneous cooperation, to efficient the channel utilizing between macro
and femto applications. A dominating challenge of this cooperation is explored, when an
efficient method is needed to distribute the usable resources, either to a femto cell or
macro cell at a certain time. Therefore, an efficient resource allocation is required to
overcome this challenge.
- Resource Allocation: The novel frequency reuse algorithm is suggested for OFDMA-
based LTE-A network by the usage of self-organising functionalities. In this process,
channel‘s physical resource blocks (PRBs) are examine as the units of this allocation, and
every cell has the responsibility to apprise the neighboring cells about its filled PRBs as
part of self-organization algorithm.
Mobility Management: The common mobile users between macro and femto uses are
needed to be fulfill in cases of mobility, especially from macro to femto, and vice versa.
The first challenge in this scenario is either the omission of handovers or facing
unimportant handovers during this strategy due to having inaccurate channel estimations
to start the handover process. Result, right handover plan is needed to plan an intelligent
handover process.

- Handover Plan: An appropriative handover plan is used by involving a novel handover
algorithm, relied on self-organising communications. The suggested multi-check plan
determine more correct calculations in the handover initiation phase, while avoiding
unimportant handovers through the system.
Interference Coordination: By the usage of identical frequency channel by both sub-
networks is expected to create higher levels of inter-cell interference. Therefore, as a
dominant challenge, network cooperation needs interference mitigation schemes to send
smooth signals to the last users. Hence, improved ICIC (eICIC) solution is involved based
on power control functionalities, for interference alleviation in macro-femto transmissions.
- Power Control: The new power control algorithm is put into femto stations‘ functional
blocks within the self-organising power balance algorithm. The power management
technique points on downlink transmission, as the primary link of interference between
macro and femto sub-networks in LTE-A.
Chapter 2
LITERATURE REVIEW
2.1 Related Work
M. Peng et al. [3] here author WiMAX is broadband wireless access system based which
defines PHY and MAC layer both fixed and mobile profiles. In this system effectively
supports wide variety of (BWA).QoS provisions are analyzed for different application
traffics.IN these provisions and mechanisms enhance QoS performance of network in term
of packet loss and delay .It can also designed to provide wireless last mile broadband
access in the (MAN).They provides high quality broadband services to fixed . WiMAX
standard to mitigate the effect of these impediments. The channel quality condition that
spectral and data and QoS performance of the network. There various service flows have

been analyzed for different application traffic and QoS performance found to in
accordance in provisions in the standard. The FTP traffic is best server with nrtPS.
T. Jansen et al. [5]: In this author proposed Network cost and network quality of services
are important concerns in the widespread deployment of WiMAX networks. This paper
presents a novel network design and optimization model for mobile WiMAX access
networks utilizing multi-hop relays. The proposed model aims to determine optimal
locations of base stations and relay stations so that the network can guarantee quality of
services in term of the access data rate and the service coverage to serve potential user
traffic demand in the area. Network technology has become potential solutions to bring
broadband internet access to people in the remote area where a wired network
infrastructure cannot reach. With the support of the IEEE 802.6. It can standard, one can
deploy the network topology using multi-hop relay. There are to enhance services of the
base stations. To enable network operators to provide low cost coverage with the quality
of services guarantee, there is a need for an efficient network design. Several works have
devoted to the studies of the performance improvement of wireless networks and the
wireless network design problems. The authors propose an adaptive cross-layer bandwidth
scheduling strategies for the hierarchical cellular networks the authors consider WiMAX
radio network planning and present the practical network deployment with performance
analysis and evaluation. Although the results give insight of the real network performance,
the mathematical model was not used to optimize the network installation. Later works in
proposed mathematical models for
Henning Sanneck et al. [8]: In this author used in optimization algorithms in order to
provide opportunistic and elible all-IP network. The real time QoS requirements of real-
time and interactive service .It can also avoid a large degree by controlling only packet
delay-jitter in the fixed and mobile environment. These applications have significantly
different traffic and term of bandwidth and communication network to offer an acceptable
performance. The system considered the SCA project is based on the use of the Internet
and wireless communication for Pre-WIMAX .The jitter and packet loss presented the
same behavior static and mobile environments. The modal can used operator to improve
main factors of QoS needed by airlines companies.

L.C. Schmelz et al.[4 ] :here author present self organization network in long term
evalution advance heterogeneous network .In this paper author proposed a two level
control machines for these service of self organization based network. SON based service
self-organization that provides service and continuity when mobile user and session
mobility can implement of better service wireless communication access. The ITU
regulates 4G Technique as per higher data rate a network convergence and seamless
connection .LTE-Advanced is always connected with data rate of maximum100Mbps and
minimum delay. It provides high-speed data communication in hot-spot area that can offer
service continuity during mobility only a mobile terminal. The LTE system to provide an
network state such as bandwidth rate change variably. Self-organization concept have
different network unite and interact for better effect and received a lot of attention as core
technology can apply
Commercial system of future mobile communication network after 4th
generation. Self –
monitoring technology for performing traffic control and improving resource capacity and
analyzing same context information of cell terminals.
H. Y. Lateef et al. [10]: Here author provide high speed broadband access is to use
wired access technologies such as cable modem. The digital subscriber line (DSL),
Ethernet and fiber optics. It is too difficult and expensive for carriers to build and
maintain wired networks. Broadband Wireless Access (BWA) is flexible, efficient, and
cost effective solution to overcome the problems. There relay station acting a
capable role of extending the range of Base station for long distances in WiMAX
networks. In this appropriate to areas with partial infrastructure such as rural,
mountainous and lake. The Base stations with each having wired connections and it
is also suitable to those areas. Where obstacles made the coverage limited. In this
paper the performance analysis of Relay stations has been done in WIMAX networks.
WiMAX is an ideal technology for backhaul applications because it eliminates
expensive leased line or fiber alternative. They can provide broadband access to
locations in worlds rural and developing areas where broadband is currently
unavailable. WiMAX has numerous advantages such as improved performance and
robustness, end to end internet protocol (IP) based networks, secure mobility, and
broadband speeds for voice, data and video.

When number of nodes increases it is observed that throughput is obtained higher
with relay station. As number of nodes increases value of throughput is observed
higher with 10 nodes. The distance increases after 200 meters the value of good put
with relay station is obtained higher than without relay station. Then distance
increases it is observed that dropped packets are obtained higher than with relay
station. Similarly for number of nodes also initially dropped packets is less but as
nodes increases value of dropped packets also increases,
Chen, Yan et al. [11]: Here author proposed WiMAX and LTE are cost efficient
service to operarators and end subscribers .The author evaluate the effect of QoS and
cost effective placement in WiMAX network . The parameters and contribute to the
technology in cost efficient manner in QoS. There scheduling algorithms are aim of
attending effective link and method and radio resource management. It can permit the
broadband service and offer reliable and fast wireless broadband.WiMAX2 highest
channel spectral and enhanced spectral at the cell edge. In mobility support were expand
to 350km/h. the two types of user one single and other multi user MIMO throughput
improvement. It can support to femtocells and low power base station increase and
coverage. They perform a relay station increase the capacity and base station technology.
They are distributed a cell to relay into coverage holes. QoS can compared various
parameter and scenarios models of WiMAX network. The factor performance can be
distance from RS to MS cell size. Two views of RS based on cost effective deployment
and QoS in RS. The small difference in throughput SNR compared with cost .the
performance may be little bit reduce an entire network. The wireless technology depends
on cell planning.
Ismat Aldmour et al. [30]: Here author proposed two wireless technology WiMAX and
LTE two process that competing technologies.LTE is an multiple heterogeneous access
technology mode. Their current activities in standardization both WiMAX and LTE
presented with a perspective the prospects of both technologies. They can both starting
their 4G version while having much in common. The technical similarities and difference
between the two technologies trying to point to point differences to other one technology.
Winning as the technology for near future public network .LTE coming from the

generation path for wireless mobile ph standing and WiMAX coming from data network
industry.
O. Oluwakayode et al. [12]: Here author the physical layer and cooperative truncated
automatic repeat request protocol at the data link layer. The first derive an exact closed
form expression. The spectral efficiency of the proposed joint AMC-cooperative ARQ
scheme. This system performance measure, then optimize an AMC scheme which
directly satisfies a prescribed packet loss rate constraint at the data-link layer. There
transmission modes at the source and relay are chosen based on the channel statistics. This
can turn quantifies the possible gain achieved by joint design of AMC and ARQ in
wireless relay networks.
The selection decode and forward protocol, still checks whether the data received at the
relay is correct, prior to a possible relay to destination retransmission . Cooperative ARQ
protocol is presented benefiting from the spatial diversity of the relay channel,
outperforms a traditional ARQ scheme, particularly.
L. Yun et. al. [15] here author performance improvement of WiMAX system using Smart
Antenna today world a larger number of wireless transmission technologies exist. They
depending upon the network such as PAN, WALAN, WMAN and WAN. They can
promise to deliver higher data rate and operators towards them. Broadband Wireless
Access (BWA) network as per need for broadband and mobile services are getting into
demand. It can increasingly acquiring a great deal of an alternative technology to DSL and
cable modems. WiMAX system is actually coming into being right now. There painless
Wi-Fi , turning your computer on will automatically connect you to closest available.
Ali et al .[16]: Here author can Device-to-device (D2D) communication is a promising
new feature in LTE-Advanced networks. The cellular networks, devices can only
communicate with the base station via uplink or downlink paths. The ever-increasing
demand of proximity-based social/commercial services and applications. The architecture
of D2D under laying LTE networks is therefore brought up to enable efficient discovery
and communication between proximate devices. There D2D have physical proximity
could be able to discover each other .LTE radio technology and to communicate with each
other via a direct data path. MAC layer functions to support D2D discovery and
communication under lying. LTE networks are analyzed. In addition, a centralized

scheduling strategy in base station is proposed to coordinate D2D data communication
operating in LTE FDD downlink spectrum. The performances of D2D data
communication under laying LTE system are calibrated in a multi-link scenario via
system-level simulation. D2D data communication is scheduled by base station with the
proposed scheduling method and the hybrid D2D and cellular system
Dutta, C. and Singh et al. [17]: Here author the performance is the best criterion for
developing any communication system. The work presented here is aimed at increasing
the speed & performance of the OFDMA (Orthogonal Frequency-Division Multiple
Access) modulator and demodulator. This paper presents a high level implementation of a
high performance FFT for OFDM Modulator and Demodulator. The design has been
coded in Verilog and targeted into Xilinx Spartan3 FPGAs. The developed OFDMA
communication structure is then targeted to the OFDMA based WiMAX communication
modules, WiMAX is poised to broadcast the Internet throughout the world, and the
changes in our lives will be dramatic. WiMAX is providing the capabilities of the Internet,
without any wires, to every living room, portable computer, phone, and hand held device.
The WiMAX modules utilize the OFDMA scheme in their physical layer of
communication. The multipath mobile broadband channel by coding and interleaving the
information across the subcarriers prior to transmission. After organizing the time and
frequency resources in an OFDMA system into resource blocks for allocation to the
individual mobile stations, the coded and interleaved information bits of a specific mobile
station are modulated onto the subcarriers of its resource blocks. Then OFDM modulation
is cost effectively realized by the Inverse Fast Fourier Transform (IFFT) that enables the
use of a large number of sub carriers— up to 1024 according to the Mobile WiMAX
system profiles to be accommodated within each OFDMA
K.M.I., Sandeep et al.[18] here author communication through high frequency band been
considered for future commercial celleular network .It ratio propagation property of
service area will increased. The sleep operation of relay station can reduce power
consumption DTMC model for relay station reduces can power. A novel energy efficiency
metric called relay energy efficiency. The author proposed relay station scheme achieves
higher energy efficiency than other conventional schemes. The base station is required to

meet the service converage cellular network environment .the density of base station of
service provider. The data rates and coverage
Dey, S and Shilpa et al [ 19]: In this author single test bed takes a large amount of time
and cost. The implementation of a whole network in real world is not easily possible and
very costly. The simulator helps the network developer to check whether the network is
able to work in the real time. The time and cost of testing the functionality of network
have been reduced and implementations are made easy. In this paper, we introduce the
main features of different simulator and consider their advantage. Then work is also
simulated on the computer. A network simulator is a technique of implementing then
works on the computer. The protocols used to handle traffic in a network, graphical
applications text-based applications advanced forms and programming-oriented tools
providing a programming framework. NS2 is a discrete event simulator targeted at
networking research. It provides support for simulation of TCP, routing, and multicast
protocols overall networks (wired and wireless).It provides an integrated , versatile , easy-
to-use GUI –based network design a network with SNMP TLI,TFTP,FTP.
Karim, et al. [20]: In this author use Worldwide Interoperability for Microwave
Access(WiMAX) is one of the newest technologies developed for broadband wireless
networks, which offers high data rate and high flexibility for the radio resource
management. Network using smart antenna is proposed. It is based on OPNET simulation
tool and uses System-in-the-Loop function to interconnect the simulated system with a
real network, for a better functional and performance evaluation. It is based on OPNET
simulator and uses the System-in-the-Loop function to interconnect the simulated system
with a real network, for a better functional and performance evaluation .The test was
developed in the framework of the SMART-Net , which aimed to investigate the use of
smart antennas in Wireless Mesh. The OPNET simulator, of a basic WiMAX network
with nodes equipped with smart antennas. It presents basic scenarios and for evaluation of
smart antennas integration on WiMAX nodes and the obtained performances. The
simulations results presented in this paper illustrate that, for fixed WiMAX nodes. The
proposed smart as will bring a significant performance gain, expressed in terms of
capacity and coverage. Because of the fast beam switching, these smart antennas can be

used successfully in fixed scenarios. The smart antenna behavior on mobile WiMAX
nodes is a subject of further research.
Anouari, T. and Haqiq et al. [24]: Here author a study of cell coverage and usage
capacity by varying distances between a relay node and a base station in a WiMAX cell.
The Network simulation version 2 (NS-2) isused to simulate a cell employing a relay node
with the light WiMAX module. A stationary user communicates with TCP data in
downlink. There are three simulation cell models. First and second models are for
evaluating cell coverage and improvement of cell coverage with a relay node. Using relay
nodes is another option which can reduce the cost. Relay nodes can improve the coverage
area and the usage capacity by using point to multi-point connections between base
stations and users. There are three types of relay node, Amplify and Forward (AF),
Selective Decode and Forward (DCF), and Demodulation and forward (DMF). A DCF
relay has the transmission performance better than others under different radio channel
condition. The relay capability is defined in mobile new generation WiMAX standard. A
WiMAX cell improvement in downlink cell coverage and usage capacity at cell edge.
There employing a relay node at different distances away from the base station. There are
three simulation models which are no relay, relay, and cell edge models, for simulating the
downlink TCP packets receiving at test node. From first model simulation results show
that without a relay node, throughput drops very fast at 200 meters away from base
station.
Thontadharya, H.J. and Devaraju et al. [29]: Here author provides wireless
transmission of data using a variety of transmission mode, from stationary point-to-
multipoint links to portable and fully mobile internet access. The technology is IEEE
802.16 and also called Broadband Wireless Access. This officially called Wireless
MAN in it has been commercialized under the name ‘WiMAX’ by the industry alliance
called the WiMAX. Their mission of the Forum is to promote and certify compatibility
and interoperability of broadband wireless. A WiMAX is bridge between short
distance communications and long distance communications and works. There other
technologies and protocols to extend the ‘last mile’ support in data communication.

The multi-hop WiMAX scenario that would possibly occur in the future can identify
and solutions are suggested and tested. There large numbers of WiMAX scenarios of
different sizes with different type of applications, models, devices, resources and
methodologies have been simulated and various aspects like mobility. QoS
interference control, traffic congestion and network balance have been studied
intensively.
Falk, et al. [27]: Here author proposed an Networks represent a good solution to offer
Internet access in sparse population areas. The latest wireless technologies, such as
WiMAX, offer high data rates services, but they are not designed for wireless mesh
architectures. This paper proposes a wireless mesh solution based on WiMAX nodes
equipped with smart antennas, and presents some tests for performance evaluation of the
proposed solution. The WiMAX mesh node is emulated by interconnecting, via Ethernet,
a Base Station and a Subscriber Station. To avoid interference between the two radio
interfaces, they are configured to operate on different frequency bands. The WiMAX
mesh node is simulated in OPNET and its performance is compared with a real life
implementation of such a hybrid mesh node. The performance evaluation was done using
an experimental platform, consisting of both a simulated and a real life part, which are
interconnected through the System in the Loop OPNET. Worldwide Interoperability for
Microwave Access (WiMAX) was developed for broadband wireless networks, and it
offers high data rate over long distances. An application suitable for WiMAX technology
is its usage in wireless backhaul networks, to provide coverage over low density areas or
as alternative solutions to wired networks. Such a solution offers resilience in disaster
scenarios obtained through self healing property facilitated by the wireless
communication. . Wireless Mesh Networks are the solution for wireless backhaul (WMN).
On one side, the WMNs share common features with ad hoc networks (MANET), on the
other side, the WMNs, being used for backbone, have minimal mobility and no constraint
on power consumption.

Chapter 3
BACKGROUND
3.1 Conventional LTE Network Multiplexing and Duplexes
LTE data transmission is totally relied on orthogonal frequency-division multiplexing
(OFDM) to carry the data on various carrier frequencies. In this regards, the usable
bandwidth is distributed into various overlapping sub-carriers. The OFDM sub-carriers are
operpendicular to each other, so the inter-symbol interference is stopped by giving
independent modulation for every subcarrier.
3.2. Supported Duplexes
In mobile systems duplex communication is the capability of the users to set up a dual-
path communication for sending and reception, instead of a simplex communication,
which has only-send or only-listen modes of operation. Two types of duplexes are
mentioned in LTE, namely: LTE time division duplex (LTE TDD) and LTE frequency
division duplex (LTE FDD).
LTE TDD
The identical frequency band is utilized for duplex in LTE TDD in both the directions,
which is also called as ―unpaired spectrum‖. The identical frequency channel hosts send
and receive processes in various time-slots in asymmetric turns. Hence, the number of
time-slots in downward link is greater than the number of time-slots in upward link.
LTE FDD
The radio transmitter and receiver works in various carrier frequencies at the identical
time, in LTE FDD. The uplink and downlink frequency bands are a parted by the
frequency offset, which stops latency, although requiring more complex circuits and
deployment. The receiver can perform an frequency depend on a time of LTE.
LTE Frame Structure
The system robustness is enhanced by splitting the sending data between various carriers.
The LTE frame structure relied of OFDM slots and FDD duplex is given on. The typical
LTE frame has the overall length of 10ms, which is distributed into 10 sub frames and 20
single slots. The length of every slot in the radio frame is 0.5ms and two slots create one

LTE sub frame of 1ms. Each slot also carry 7 OFDM symbols involving common (short)
cyclic prefix with a copy at the last of the symbol. The most essential function of cyclic
prefix is to work as a guard interval to stop the inter-symbol interference between the
symbols. If to include the frequency domain into our structure, every of the OFDM
symbols involves 12 subcarriers, which together make one physical resource block (PRB)
as the most essential unit in LTE in various measurements. Hence, we can tell one two-
dimensional unit in LTE is one PRB, which is built of one slot in time domain and 12
subcarriers in frequency domain. Other two-dimensional unit in LTE is one Resource
Element, which is built of one symbol in time domain and one subcarrier in frequency
domain.
Figure 3.1: LTE Frame Structure
3.3 OFDMA in Downlink
LTE downlink utilise orthogonal frequency division various access, which gives OFDM-
based multiplexing for various access. OFDMA gives low-data rate sending and lower
maximum transmission power from various users. This also further enhances the existing
OFDM robustness, fading and interference removal. They give the subcarriers in OFDMA
multiplex.

Figure 3.2: Multiple subcarriers configuration in OFDMA
The deployment flexibility across various frequencies requirements minimum
modification by the usage of orthogonal frequencies in OFDMA. Scalability of OFDMA
is one of the much essential advantages, in which its subcarrier structure built it capable to
support a widely range of bandwidth. The scalability of this multiplexing scheme also
gives more flexibility of deployment with minimum changes to the existing air interface.
This system is capable to be deployed in various frequency band intervals to address the
various spectrum allocation schemes. In the case of sending methods, since the processing
of OFDMA signal gives effective frequency flat channels, complete multi-input-multi-
output (MIMO) technology could be deployed in integration with existing OFDMA
system , which could be greatly utilize in later versions of LTE-Advanced.
3.4 SC-FDMA in Uplink
In LTE-A uplink, individual carrier frequency division various access (SC-FDMA) is
preferred over OFDMA, because it diminish the peak to average power ratio (PAPR). The
SC-FDMA process has identical structure to OFDM and OFDMA, except the joining of a
discrete Fourier transform (DFT) block before representing the subcarriers. Hence, SC-
FDMA could also be determined as an OFDMA modulation, but with an additional DFT
block. SC-FDMA is more desirable instead of OFDMA, since it diminish the PAPR by a
ratio of the dimensions of the opposite DFT (IDFT) and DFT in its modulator, which
diminishes cost of power amplifier for mobile users. They can describe the symbol
sending of OFDMA and SC-FDMA [30].

Figure 3.3: OFDMA vs SC-FDMA transmissions
3.5 Necessity of Self-Organising Approaches for HetNets
Latest version of LTE-A systems, which are more pointed on heterogeneous networks,
plans to satisfy coverage and capacity needs. Relation of the advanced release of LTE with
heterogeneity from one side, and self-configuration plans in every step of LTE-Advanced
made the other side, could make a heuristic process in this regard. Figure 3.4 depicts the
self-organisation process in cellular networks.

Figure 3.4: Self-organization process in cellular networks
3.5.1. SON Solution for Resource Allocation
The LTE base stations are required to be equipped with SON abilities to diminish human
involvement, as well as preserving capital expenditures (CAPEX) and operational
expenditures (OPEX). Determining the exponential achievement of data traffic, channel
optimization is the primary goal of resource allocation schemes in LTE-A systems. Hence,
schemes like fractional frequency reuse, incomplete reuse and channel sharing are planned
along with SON algorithms for network cooperation, e.g. macro-femto cooperation, in
case of frequency re-use strategies.
3.5.2. SON Solution for Mobility Management
Unimportant handovers are seen as the critical challenge in network mobility
management, which are technically due to the inaccurate network measurements.
Moreover to plan a ubiquitous network support, it is important to prevent any needless

handover, e.g. unimportant macro to femto handovers. Self-Organizing mobility
management algorithms begin a comprehensive handover process with more right network
situation monitoring to maximize network reception and lessen the number of unimportant
handovers within the cells.
3.5.3. SON Solution for Interference Coordination
The network cooperation is included to decrease the complete costs for the network
operators. The inter-cell interference management has appropriate in concept of HetNets,
due to the essential of interference as one of the big challenges in OFDMA-based
networks [13]. In downward link side of network, where the network node sends to a
variety of users, more challenges are required to be faced due to greater interference.
Sending of power is also essential to control purpose of managing the interference in the
neighboring cell, as well as the goal cell.
Hence, it appear very logical as a common practice for LTE, to use less sending of power
near the cell border purpose of apply interference mitigation measures and diminish the
inter-cell interference.
3.6. Deployment Structure and Interfaces
As an OFDM-based scheme, LTE technology is prioritized over the conventional 3G
version by its physical characteristics. The explained OFDMA and SC-FDMA transmissions
are attened by channel optimization schemes, like co-channel deployment, to get positive
influences on QoS satisfaction for the end users. Moreover, supported modulation techniques
and interface architecture are also appropriate characteristics of LTE network, which could
transport network capacity improvements.
3.6.1. Deployment Methodologies
In little-cell deployment, macro-femto cooperation needs certain network design to deploy
a dual-path transmission by use of bandwidth resources. The deployment methodology of
macro and femto sub-networks gives channel allocation and resource blocks sending,
either by sharing the frequency channels or by allocating apart channels.
Multi-Channel Deployment
In multi-channel deployment, macro and femto nodes use apart frequency channels for
transmission. In this arrangement, single or multiple frequency bands are gave to each

application, which could prevent co-channel interference due to the using different
frequency channels. Avoiding interference by using apart channels could increase quality
of service by diminishing number of dropped packets in the network layer and raising the
number of effective transmissions. Though, on the other hand, the multi-channel
deployment scheme could not satisfy the channel optimization and financial expectations.
Co-Channel Deployment
Use of identical frequency channels for outdoor and indoor applications is favored in
LTE-Advanced. The co-channel deployment abilities of heterogeneous networks give the
benefit of channel optimisation, which diminish the network implementation expenditure
by saving more frequency channels. However, a heuristic macro-femto cooperation
scheme is needed for this type of deployment, not only to prevent the co-channel
interference, but also to arrange other network layer responsibilities among the sub-
networks, e.g. handover and resource managements.
3.6.2. Modulation Schemes
The quadrature amplitude modulation (QAM) is utilized to modulate the transmitted bits
within the OFDM signal in LTE distributed channels. Applying various modulation
techniques in LTE makes the bit detection process more appropriate against distortion and
noise within the sending of channel. Three types of modulation stratigies are used as
depicts.
Figure 3.5: Modulation types in LTE
In case of caring noisy channel situations, the modulated data with quadrature step shift
keying (QPSK) gives more reliable decision at the receiver side,
Due to a great distance between the modulations points (2 bits per symbol). On the other
side, 16QAM and 64QAM map 4 and 6 bits onto one modulation symbol respectively,
which targets higher data throughput when the SNR on the sending channel is greater.

3.6.3. Interface Architecture
The air interface of LTE network is refered to evolved universal terrestrial radio access
network (EUTRAN), which is communicate to the evolved packet core (EPC)
configuration. The LTE interface architecture is mentioned. The X2 interface gives inter-
connections among macro nodes (eNodeB). The total X2 interface is relevant for the
nodes within a unified network, and not single networks like home or indoor uses.
Figure 3.6: Entire LTE interfaces architecture
The S1 interface is used to join Nodes to the EPC platform by the management and system
architecture gateways. Hence there is ability to install S1 interface between small-cell
nodes, e.g. femtocells (HeNodeBs), and EPC through the suitable gateways.
3.7. Channel Sharing and Access Control Necessity
The 3rd generation partnership project (3GPP) Version 10 LTE-A has been revealed with
further improvements to the LTE systems to satisfy IMT-Advanced expectations.
Heterogeneous networks, as a appropriate improvement of LTE-A over LTE, needs
channel use and access control to be determine to optimize the bandwidth allocation
among variety of the sub-networks.
3.7.1. Resource Allocation Scheme
The node choosing in LTE Rel-8 is relied on downlink received signal strongness.
Determining the same scheme for LTE-A, the usefulness of low-power nodes will be

greatly diminished. The reason is, because of greater power and larger coverage of
macrocell, they pull most of the user terminals, while not giving sufficient resources to
effectively serve those users. Hence, the first consideration of resource allocation is the
good distribution of channel resources, which is essential to balance the traffic and prevent
QoS remove within the network.
3.7.2. Frequency Reuse Pattern
Frequency reuse scheme is globally used on the existing generations of cellular networks,
in which the transmission of various cells or sectors of a cell are orthogonalised in the
frequency domain by separating the total usable spectrum into non-overlapping segments.
The usage of wide channels for LTE and LTE-A networks limits the usable spectrum,
which targets in performance and quality reductions in every cell. Hence, the application
of improved techniques for frequency reuse is essential to start the channel optimization.
The depicts two different techniques for frequency reuse within neighboring cells.
Figure 3.7: Different frequency reuse strategies
Although the frequency reuse style results in the preserving of bandwidth resources,
applying the identical frequency for the neighboring cell sectors targets in Interference and
network quality reduces, particularly for the users at cell boundaries.
3.7.3. Network Access Modes
It has been proved that the traffic offload to femtocells can diminish the prices for the
network operators by up to 70%. Hence, network access is another essential sub-network
function, e.g. for indoor nodes, which is needed for access by public users. Different

network access modes are categorized relied on network allowance to the users to be
arranged by the transceivers within each geographic portion.
Open Subcarrier Group: In open subcarrier group (OSG), also refered to as ―Open
Access‖ mode, the network user groups have instant access to any portion of the network
upon need. In macro-femto network, both macro users and indoor users can utilize the
Femtocell, while there is no such list of permitted users in femto access points.
Closed Subcarrier Group: On the other side, there are a few problems due to
installment of a greater number of low-power nodes. Generally in co-channel installment
scenarios in heterogeneous networks, interference may become complex due to usage of
low-power nodes, which could guide to large outage of the macro users. The femtocells is
capable to work in a closed subcarrier group (CSG), also named as ―Closed Access‖
mode, in which a list of permitted users is gave for the Femtocell. In this mode, only the
users usable on that list, i.e. CSG user, are permitted to access to the femtocells. Since the
possibility of inter-cell interference in CSG is greater than OSG, suitable interference
coordination techniques are important to be planned in network cooperation.
Hybrid Access Mode: Hybrid access mode is a new aspect in addition to open and
closed access modes, which is suggested in LTE release. In hybrid access mode, all the
users have open access to the cell, but those users who are subscribed have superiority to
obtain access and get charged differently . Hence, the cell behaves UEs as CSG if their ID
is in the access list and provides them priorities; otherwise it behaves them as OSG and
serves them as normal.
3.8 Related Work:
There have been an raising in global need for wireless data services as well as real-time
uses like VoIP, audio and video streaming (Sengupta, Chatterjee & Ganguly, 2008); this
increasing needs is as a result of rapid achievements which has been massively witnessed
in various wireless technologies currently. Countless researches are occurring in areas of
wireless technologies deployment (generally WiMAX) using Voice over IP based network
system, all in a offer to come up with a communication system that will be capable to give
optimal wireless services so as to meet the enhancing user demands. As self-reliant units,
holons have a degree of independence and manage circumstances and problems on their

certain levels of existence without reaching greater level holons for assistance. The self-
reliant characteristic suggests that holons are stable, capable to sustain disturbances.
In (Flizikowski, Majewski, & Przybyszewski, 2010), the authors have inquired to a
remarkable extent the audio, data and video support characteristics in WiMAX Networks.
Their research was focused on determining the QoS installment over WiMAX Networks
and comparison of the performance got using WiMAX service classes like Unsolicited
Grant Service (UGS) and extended real time Polling Service (ertPS). The studies executed
by these authors have assured that WiMAX Networks supports real-time uses more
compared to other wireless access technologies like WLAN and 3G.
A traffic-aware scheduling algorithm for the installment of VoIP applications over
WiMAX Networks have been suggested in (Ansari & Haghani, 2008), the authors
critically determine the performance of the suggested method in comparison with different
notable conventional methods. They further mentioned how the effectiveness of VoIP
over WiMAX networks performance can be enhanced upon by the use of their suggested
scheduling methods. But their proposed algorithm was not inquired under known
performance metrics to determine and set up its robustness in QoS supports.
Rong et al. (2007) suggest an integrated adaptive power allocation (APA) - call
admission control (CAC) downward link resource management framework for
OFDM-TDD based multiservice network by caring into account the service giver and
subscriber. This study generate algorithm of both.
Niyato and Hossain (2007) suggest a pricing model for adaptive bandwidth sharing in an
combined Wi-Fi/WiMAX network. Game theory has been ustilize to analyze and get
pricing for bandwidth sharing between a WiMAX base station and Wi-Fi access point
routers.
Hung-Yu et al. (2005) discussed the interference issues and suggest an effective approach
for using of WiMAX mesh by the design of multi-hop routing and scheduling algorithm
technique. This technique determined both traffic load need and interference situations.
Simulation results depicts that the suggested schemes effectively enhanced the network
throughput performance in IEEE 802.16 mesh networks and got high spectral utilization.
A scheduling mechanism and a routing algorithm is generated (Liqun et al. 2005) to
maximize the spatial reuse in wireless mesh networks and to obtain better network

throughput and spectral effectiveness. The model needs the receiver to be free of
interference and determines the interference range as equal to the communication range.
The authors in (Shrivastava & Vannithamby, 2009) handle that though WiMAX Networks
are effective in supporting data traffic, the capability of VoIP when install over IEEE
802.16e WiMAX system is not impressive as a target of overwhelming MAP overhead
always produced by dynamic scheduling of VoIP traffic. In their work, they took
persistent scheduling as a mechanism in IEEE 802.16e WiMAX system in order to lessen
MAP overhead happening. The only deficiency inherent in their suggested
persistent/group scheduling process is that it made sort of ―resource hole‖ in the slot at the
data allocation portion which guide to inefficient resource providing. Majority of the VoIP
QoS inquires have been worked on Ethernet LAN, Wireless LAN as opposite to WiMAX
access networks. In most of the events where it has actually been done with the
installment of WiMAX networks, the researchers have failed to see at some notable
complicated codec algorithms/schemes with decreased value of voice frame size per
packet that can be perform on voice/video calls/conference to increase the quality of VoIP
performance when installed over WiMAX Networks. These complicated codec schemes
gives tremendous compression effectiveness that saves network bandwidth importantly in
wireless schemes like WiMAX networks. However, majority of the researchers that have
done some associated work on inquiries of VoIP system performance when installed over
WiMAX networks used other network simulators such as NS-2, E-modeling, NetSim, etc
for designing, modeling and simulation of the network which most computer networking
students and professional industrial practitioners are not quite very much conversant with.
This research will utilize OPNET Network Simulator which is preference universal among
IT students and communication professional to see at the performance criteria as well as
some codec algorithms allowed and curtained by ITU-T for voice and video conferencing
by the usage of VoIP over IEEE 802.16e standard WiMAX networks in a campus
network.
A research (Ghosh et al. 2008) explains the IEEE 802.16 standard for stable WiMAX
802.16d. This standard is also named as 802.16-2004, which gives high data rate over a
large portion by reusing frequency. Moreover, this study examines only the throughput
and does not determine delay, jitter, latency and packet loss. Another research (Fong et al.

2004) shows an overview of different features of Broadband Wireless Access to support a
fastly growing network. This research integrate the scalability with WiMAX standards
such as IEEE 802.16 and a hierarchical Local Mobile
Klund et al. (2008) mentioned the history of WiMAX standards and its benefits such as
MAC of IEEE 802.16, which support various transport technologies involving Internet
Protocol release IPv4, IPv6, Ethernet and Asynchronous Transfer Mode (ATM). The
WiMAX 802.16e helps power preserving and sleep modes to enlarge the battery life of
mobile devices and it also supports hard and soft handoffs to give users with seamless
joints. Another research (Hoymann 2008) states four different Physical (PHY) layers but
determines only the Orthogonal Frequency Division Multiplex (OFDM) layer. A summary
of the OFDM based transmission mode of the WiMAX IEEE 802.16 standard is
represented. The MAC and PHY layer are mentioned in detail. The MAC layer
configurations with various levels of robustness are also analyzed.
A research (Sayenko et al. 2009) gives the estimation for WiMAX MAC header overhead
to reserve enough amounts of slots for the constant-rate uses. This research shows many
simulation scenarios to demonstrate how the scheduling answer allocates resources in
different cases. The scheduling answer was relied on the round-robin scheduling. The
simulation scenarios execute in ns-2. It could be more appropriate if the study could give
comparative results compare with other wireless technologies MAC header overhead to
integrate value to the results.
Jain et al. (2009) suggest a multi-channel Carrier Sense Multiple Excess (CSMA) with
collision avoidance scheme. This research evaluates the performance of receiver based
channel choice, comparing with IEEE 802.11 Distributed Coordination Function (DCF)
using ns-2 simulator. Moreover, at a given time, one packet can be sent only on any
channel, but many packets can be received at different channels at the same time.
A research (Chatterjee et al. 2007) utilize Forward Error Correction (FEC) and Automatic
Repeat Request (ARQ) to support streaming services and examining the problem of real
time streaming media over WiMAX and exploited the flexibility characteristics in
MAC layer of 802.16a standard. The authors suggest the size of MAC packet data units
to create adaptive to the instantaneous wireless channel situation.

Huang et al. (2009) mention that a good scheduling control is complex to support mixed
VOIP (Voice over IP) and for non-real time services in mobile WiMAX as given in the
802.16e standards which gives mobile support in cellular deployments.
Table I: Literature review
Author Title Work
J Jaffar et al Performance
Analysis of VoIP
Codecs over
MPLS Networks
[2009]
Here authors evaluates the quality of service of
video transmission on Differentiated Services
(Diff-Serve) with Multiprotocol Label Switching
(MPLS) network is being simulated. The
objective of this thesis is to study the influence of
the QOS mechanism via DiffServ-MPLS on
network parameters such as
Packet loss, delay and throughput for different
video resolutions.
Haniyeh
Kazemitabar et
al
A comprehensive
review on VoIP
over Wireless
LAN networks
[2012]
This thesis has demonstrated a survey on VOIP
over WLAN, its advantages and challenges and
also VOIP capacity over WLAN and the number
of calls for different voice codecs and intervals
based on IEEE 802.11b standard.
M.A. Mohamed
et al
Performance
Analysis of VoIP
Codecs over
WiMAX Networks
[2012]
Here authors evaluate the performance of
different VOIP codecs over the WIMAX network.
Simulation results show that the G.723 is better
than codecs G.711, G.726, G.728 and G.729
because it has lower delay and higher MOS,
traffic received and throughput.
Mohd Nazri
Ismail et al
Performance
Evaluation of
Audio Codecs
using VoIP Traffic
in Wireless LAN
using RSVP
[2013]
This thesis deals with VOIP over VPN
implementation between open source application
and hardware device in campus environment. In
this, the evaluation of performance of CPU
Utilization, Jitter, Delay, Memory Usage and
MOS(mean opinion score).

Elechi
Onyekachi et al
Investigating the
QoS of Voice over
IP using WiMAX
Access Networks
in a Campus
Network [2013]
This thesis attempts to identify some of the
network performance parameters that service
providers will focus on to develop a VOIP over
WIMAX communication tool that will serve as a
voice communication broadband replacement
technology to old circuit switch voice
communication.
Mojtaba
Seyedzadegan
et al
SPEECH
QUALITY
EVALUATION
BASED CODEC
FOR VOIP OVER
802.11P [2013]
This thesis provides the quick and technical
overview of concept, standard, technology and
architecture for IEEE 802.16 WiMAX.
D.Ramesh et al Techniques to
Improve
Performance of
VoIP over 802.11e
WLAN [2013]
In this thesis authors presented a Media Access
Control Protocol that provides the quality of
service for VOIP over wlan. In this, the
characteristics of our proposed protocol are No
hardware modification of VOIP STA. Backward
compability in order to minimize the cost of
development no modification of access points.
Preetinder
Singh et al
VOIP Over
Wimax: A
Comprehensive
Review [2014]
This thesis provides focusing on quality of service
scheduling services and performance related
metrices such as jitter, packet end to end delay
and MOS(mean opinion score).
Dr. Abdul-Bary
R.Sulaiman et
al
Performance
Analysis of VoIP
Codecs over
MPLS Networks
[2014]
This thesis evaluated the performance measures
such as delay variation, delay, page response
time, throughput and packet drop for different
types of traffic such as voice, video, data in their
movement in a congested network for both
MPLS-TE and Conventional IP Network.
Rahul Singh et
al
A Review Thesis:
Voice over Internet
Protocol [2014]
This thesis deals with VOIP to a level that allows
discussion of security purposes and concerns. In
this, VOIP components will include network
components, gateway, end user equipment, call
processors and two of common architectures.
Lamia Bakri Evaluation of Here authors the network performance analysis to

Abd Elhaleem
Derar et al
Voice Codecs of
VoIP Applications
for UMTS [2014]
evaluate the effects of the application of different
voice encoder schemes on quality of service of
VOIP system which is deployed with the UMTS
network.
Fourty et al. (2010) determined and classified wireless networks. This study proposed that
WiMAX made the possibility to get a connectivity of the identical type as the rented lines
used by network‗s operators for the Internet or telephony transmission T1 (for American
suppliers) or E1 (for European suppliers).
In their specific researches in (Salah, 2009) and (Yanfeng & Aiqun, 2006), the authors
prove that it is important that the abilities of a network to support VoIP applications be
determined prior to its arrangements with such network. According to them, the network‘s
readiness to support installment with VoIP system could be inquied by usage of network
modeling and simulation approaches, measuring for voice packet end-to-end delay, voice
packet delay variation, throughput and voice jitter after inserting real time (VoIP) traffic
into the network. The author‘s argument if adhered to, will aid in solving a high deal of
problem as it will preserve both time and resources instead of just installing real-time
applications such as VoIP with just any wireless access scheme without prior inquiry of
whether such network has any real-time use support capabilities or not. With reference to
Halepovic, Ghaderi & Williamson, (2009), VoIP system has become greatly famous more
than ever even as WiMAX Networks are been install in many countries across the globe.
Hence, many researchers in current years as well as recently have points extensively on
different characterstics of VoIP services over WiMAX networks, all focused on inquiring
and identifying network add-on performance standard that will increase the quality of
service delivery of VoIP system over WiMAX networks.
3.9. LTE-Advanced Technical Challenges
Installing the existing LTE platform in the transition to advanced LTE systems guides to
challenges in different aspects such as network capacity, quality of service, resource

scheduling, handover planning, inter-cell interference coordination, etc.
Figure 3-9: Technical challenges in a HetNets scenario
A concise explanation and important suggestions are done in this section to become more
familiar with the primary technical challenges when working with new versions of
heterogeneous LTE network. Figure 2-11 depicts a typical HetNets scenario with its
technical challenges.
3.9.1. Capacity and Coverage Support
The mean ability of the network is determined as aggregated throughput from all users
combined to a single cell. However, the average cell coverage is also determined as the
lowest user throughput that can be assurance in 95% of cases. The ability and coverage
optimisation algorithms could assures acceptable values for ability and coverage by
raising the transmission power provided to a physical resource block (PRB), but also
causes more inter-cell interference. Hence the suitable ICIC technique is also required to
be considered along with these algorithms.
3.9.2. Overall Quality of Service in HetNets
Though the network MIMO is provided in LTE-Advanced systems, it does not
recommend a assured quality of service. There are some challenges associated to timing
issues of the packets belonging to various streams in a different QoS network. The first
challenge is the usage of MIMO to arrange the packet sending with different QoS

characteristics, and the second challenge is searching of suitable radio resources for each
stream to assure QoS for various MIMO topologies. Therefore, QoS satisfaction is needed
to be determined, while giving coverage and ability planning.
3.9.3. Channel Optimization and Resource Allocation
The wants of having a heuristic resource allocation plan is more dominanting when a
variety of uses are install within HetNets architecture. The resource partitioning could be
install with various schemes, such as time-domain, frequency-domain, or spatial-domain.
The time-domain partitioning could greater adapt to user distribution and traffic burden
modifications, while the frequency-domain partitioning is less granulous and brittle for
resource allocation, but is more manageable in asynchronous networks. Hence, giving a
self-organising resource allocation could be more efficient.
3.9.4. Mobility Management and Handover
Different issues require to be considered to get the greater outcome in case of users‘
mobility. User speed, useable bandwidth, macro and femto superiority, power of the
sending signal, etc. are important to be determined to maximise the network throughput.
The unimportant handovers also required to be minimized to obtain to the utmost
effectiveness in case of users‘ mobility.
3.9.5. Interference Challenge and Mitigation Plan
The interference alleviation scheme is generally categorized into three primary schemes
of: interference cancellation, interference averaging and interference avoidance
techniques. Giving of the interference avoidance plan results increased performance with
less complexity within the network, contrasting to the interference cancellation and
averaging stratigies. Hence the interference mitigation technique is preferred to be applied
within the complete network. The most appropriate challenge in this regard is building a
trade-off between channel optimisation and an interference-free network, which is planned
to be addressed by development of inter-cell interference coordination (ICIC) algorithms

LTE handover

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