4G Femtocells: Resource Allocation and Interference Management

85 Pages·2013·1.823 MB·English

by  Haijun Zhang, Xiaoli Chu, Xiangming Wen (auth.)

SPRINGER BRIEFS IN COMPUTER SCIENCE
Haijun Zhang
Xiaoli Chu
Xiangming Wen
4G Femtocells
Resource
Allocation and
Interference
Management
123
SpringerBriefs in Computer Science
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StanZdonik
PengNing
ShashiShekhar
JonathanKatz
XindongWu
LakhmiC.Jain
DavidPadua
XueminShen
BorkoFurht
VSSubrahmanian
MartialHebert
KatsushiIkeuchi
BrunoSiciliano
Forfurthervolumes:
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Haijun Zhang • Xiaoli Chu (cid:129) Xiangming Wen
4G Femtocells
Resource Allocation and Interference
Management
123
HaijunZhang XiaoliChu
CollegeofInformationScience DepartmentofElectronic
andTechnology andElectricalEngineering
BeijingUniversityofChemical TheUniversityofSheffield
Technology Sheffield,UK
Beijing,China,People’sRepublic
XiangmingWen
BeijingUniversityofPosts
andTelecommunications
Beijing,China,People’sRepublic
ISSN2191-5768 ISSN2191-5776(electronic)
ISBN978-1-4614-9079-1 ISBN978-1-4614-9080-7(eBook)
DOI10.1007/978-1-4614-9080-7
SpringerNewYorkHeidelbergDordrechtLondon
LibraryofCongressControlNumber:2013947965
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Preface
Femtocells have been considered as a promising technology to provide better
indoor coverage and spatial reuse gains in the last few years. Femtocells are low
power,lowcostanduserdeployedwirelessaccesspointsthatuselocalbroadband
connections as backhaul. Not only the users but also the operators benefit from
femtocells. On the one hand, users enjoy high-quality links; on the other hand,
operators decrease the operational expenditure (OPEX) and capital expenditure
(CAPEX) due to the traffic offloading and user’s self-deployment of femtocell
base stations (FBSs). Orthogonal frequency division multiple access (OFDMA)
basedfemtocellshavebeenconsideredinmajorwirelesscommunicationstandards,
e.g.,LTE/LTE-Advanced.Due to spectrumscarcity andimplementationdifficulty,
spectrum-sharing,ratherthanspectrumsplitting,betweenfemtocellsandmacrocells
ismorepreferablefromtheoperator’sperspective.However,co-channeldeployed
femtocellsmayleadtosevereco-channelinterferencebetweenfemtocellsindense
deployment,andcross-tierinferencebetweenmacro-tierandfemto-tier.
Duetothefadingcoefficientsofdifferentsubchannelsarelikelytobeindepen-
dentfordifferentusers,whichareknownasmultiuserdiversity(MUD),maximum
system spectral efficiency can be achieved by selecting the best user for each
subchannel and adapting the associated transmit power. Therefore, resource allo-
cationisoneofthemostimportanttechniquesforfemtocellstomaximizespectral
efficiencyandmitigateinterference.Powercontrolandsubchannelallocationhave
been widely used to alleviate cross-tier and/or co-tier interference and satisfy
diversequalityofservice(QoS)forco-channeldeploymentoffemtocells.However,
there has not been any book specifically addressing femtocell network resource
allocation with various objectives, constraints and optimizing variables taken into
consideration.
Inthisbook,weaddresstheforegoingissuesandprovideanin-depthdiscussion
on the latest resource allocation and interference management issues for femto-
cells. The discussion begins with introducing femtocells and their development
in Chap.1. After that, resource allocation in dense deployed femtocells is inves-
tigated in Chap.2. Such techniques include user scheduling and power control to
maximize capacity of femtocells. In Chap.3, an interference-aware pricing-based
v
vi Preface
resource allocation algorithm for co-channel femtocells is proposed to alleviate
their interference to macrocells without degrading the femtocells’ capacity. The
subchanneland power allocation problem is modeled as a non-cooperativegame.
A suboptimal subchannel allocation algorithm and an optimal power allocation
algorithm are proposed to implement the resource allocation game. In Chap.4,
resourceallocationisinvestigatedinbothuplinkanddownlinkfortwo-tiernetworks
comprising spectrum-sharing femtocells and macrocells. A resource allocation
scheme for co-channel femtocells is proposed, aiming to maximize the capacity
for both delay-sensitive users and delay-tolerant users subject to delay-sensitive
users’ QoS constraints and the interference constraint imposed by the macrocell.
The subchannel and power allocation problem is modeled as a mixed integer
programming problem, then transformed into a convex optimization problem by
relaxingsubchannelsharing,andfinallysolvedbythedualdecompositionmethod.
Thecomplexityoftheproposedalgorithmsisanalyzed,andtheeffectivenessofthe
proposedalgorithmsis verifiedby simulations.InChap.5, we proposean energy-
aware uplink power control scheme for two-tier femto-macro networks based on
non-cooperativegame.InChap.6,weproposeadifferentiated-pricingbasedpower
allocationalgorithmfortheuplinkofspectrum-sharingfemtocells,basedonanon-
cooperativegameframework.Concludingremarksandfuturetrendsareprovidedin
Chap.7.
Beijing,China,People’sRepublic HaijunZhang
Sheffield,UK XiaoliChu
Beijing,China,People’sRepublic XiangmingWen
Contents
1 Introductionto4GFemtocells............................................... 1
1.1 4GFemtocellNetworks.................................................. 1
1.2 ResourceAllocationandInterferenceManagement.................... 2
1.3 ChallengesandIssues.................................................... 4
References...................................................................... 4
2 AntColonyAlgorithm(ACA)BasedDownlinkResource
AllocationinFemtocells...................................................... 7
2.1 Introduction .............................................................. 7
2.2 SystemModelandProblemFormulation............................... 8
2.2.1 SystemModel.................................................... 8
2.2.2 ProblemFormulation............................................ 10
2.3 ResourceAllocationUsingACA........................................ 10
2.3.1 ApplicationofACAinResourceAllocation................... 11
2.3.2 AlgorithmDescription........................................... 12
2.3.3 ParametersandConvergenceofACA .......................... 14
2.4 PerformanceEvaluation ................................................. 14
2.5 Conclusion ............................................................... 17
References...................................................................... 17
3 Cross-TierInterferencePricingBasedUplinkResource
AllocationinTwo-TierNetworks............................................ 21
3.1 Introduction .............................................................. 21
3.2 SystemModelandProblemFormulation............................... 23
3.2.1 SystemModel.................................................... 23
3.2.2 ProblemFormulation............................................ 25
3.3 Interference-AwareResourceAllocation ............................... 25
3.3.1 AGameTheoreticFramework.................................. 26
3.3.2 Interference-AwareSubchannelAllocation .................... 27
3.3.3 Interference-AwarePowerAllocation .......................... 28
3.3.4 Semi-distributedImplementation............................... 29
3.4 SimulationResultsandDiscussion...................................... 30
vii
viii Contents
3.5 Conclusion ............................................................... 33
References...................................................................... 35
4 Resource Allocation in Femtocells with Cross-Tier
InterferenceLimits ........................................................... 37
4.1 Introduction .............................................................. 37
4.2 SystemModelandProblemFormulation............................... 39
4.2.1 SystemModel.................................................... 39
4.2.2 ProblemFormulation............................................ 39
4.3 SubchannelandPowerAllocationAlgorithm.......................... 40
4.3.1 Transformation of Optimization Problem
byTime-SharingRelaxation .................................... 41
4.3.2 DualDecompositionMethod.................................... 42
4.3.3 IterativeResourceAllocationAlgorithm....................... 44
4.3.4 DownlinkCase................................................... 45
4.4 SimulationResults and Discussions.................................... 46
4.5 Conclusion ............................................................... 49
References...................................................................... 49
5 Energy Efficient Power Control in Femtocells with
InterferencePricing .......................................................... 51
5.1 Introduction .............................................................. 51
5.2 SystemModelandProblemFormulation............................... 52
5.2.1 SystemModel.................................................... 52
5.2.2 ProblemFormulation............................................ 53
5.3 Non-cooperativePowerControlGamewithConvexPricing.......... 54
5.3.1 FemtocellUtilityFunction ...................................... 55
5.3.2 Super-ModularGames........................................... 55
5.3.3 Energy-AwarePowerControlNPG-CP ........................ 57
5.4 PerformanceEvaluation ................................................. 58
5.5 Conclusion ............................................................... 60
References...................................................................... 61
6 Differentiated-PricingBasedPowerAllocationinDense
FemtocellNetworks........................................................... 63
6.1 Introduction .............................................................. 63
6.2 SystemModelandProblemFormulation............................... 64
6.2.1 SystemModel.................................................... 64
6.2.2 ProblemFormulation............................................ 65
6.3 Differentiated-PricingBasedPowerAllocation ........................ 66
6.3.1 GameTheoreticBasedonDifferentiatedPricing.............. 67
6.3.2 Differentiated-PricingFunction................................. 69
6.3.3 DynamicPowerAllocation...................................... 70
6.4 SimulationResultsandDiscussion...................................... 70
6.4.1 SimulationParameters........................................... 70
6.4.2 PerformanceAnalysis ........................................... 71
Contents ix
6.5 Conclusion ............................................................... 72
References...................................................................... 73
7 ConclusionsandFutureWorks.............................................. 75
7.1 Conclusions .............................................................. 75
7.2 FutureWorks............................................................. 76