Resource Allocation Schemes High Speed Wireless Access Networks

140 Pages·2002·7.46 MB·English

Resource Allocation Schemes for High Speed
Wireless Access Networks
Rathneswaran Vannit hamby
-1t hesis submit ted in conformit y wi t h the requirements
for the Degree of Doctor of Philosophy,
Department of Electrical and Cornputer Engineering:
at the University of Toronto
@ Copyright by Rathnemaran Vannithamby 2001
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To my late father and rny family
Resource Allocation Schemes for High Speed Wireless
Aeeess Networks
Rat hneswaran Vannit hamby
Degree of Doctor of Philosophy
Department of Electrical and Cornputer Engineering
University of Toronto
2001
Abstract
The focus of this thesis is to efficiently allocate the radio resources in novel ways to achieve
performance benefits in CDMA systems through proper channel access control techniques.
The capacity of the integrated services with different data rates and quality of service re-
quirements is analyzed. It is first shown that the system performance deteriorates when voice
and high data rate services are integrated. To improve the system performance. a channel access
control technique for deiay insensitive high data rate traffic is proposed.
Resoiirce allocation and schediiling sciiemes arc! proposed and sti idietl for a systeni wi t h only
high data rate Internet users. The scheduling schemes exploit the packet mode trarisniission
to achieve better performance in the time-slotted systems where rates are aliocated according
to the channel conditions. These schernes are compared in terms of throughput and delay. and
also fairness in the allocated data rates. It is shown that the overall system performance is
severely afTected by the adverse channel conditions seen by a few users. To improve the system
performance. a technique is proposed that identifies and delays the transmission for stich users
until the conditions improve.
A tirne muse duster size of three ceb is considered tu mininrize the interference. Whcn
the cluster size is Iarger than one cell, the transmission From neighboring base stations niust be
coordinated. To efficient Iy reuse the t ime, aigorithms are developed for best-effort and real-t ime
services. A dynamic time share allocation algorithm is proposed and studied that can uniquely
coordinate the transmission time for high data rate Internet users in time reuse clusters larger
than one ceI1. A time slot assignment scheme is &O proposed and studied for real-tirne high data
rate services. It efficiently packs and dynamicdy ailocates the time slots so that the cal1 blocking
probability is lower than various fixed and dynamic schemes in aU t r a c c onditions.
Acknowledgements
1 would like to thank my supervisor Prof. Elvino S. Sousa for his invaluable advice.
guidance. support and patience. He has always been accessible and very helpful.
1 would also like to thank my Ph.D. Committee. Prof. R. Bonert. Prof. J. Friedlander
. .
(Math emat ics Dept .) Dr. B. Hashem (extemal appraiser from Norte1 Networks) Prof. K.
Y. Plataniotis and Prof. A. 3'. Cénetsanopoulos.
1 am thankful to my colleauges in communications group, especially the wireless group
for providing a pleasant working atmosphere and good conversation. Special thanks to
Alagan, Halim and Wilson.
Sarah Cherian's and Diane Bettencourt Silva's administrative help are also grateful1y
acknowledged.
During this work. 1 assisted by the financial support provided by NSERC. CITO.
IVBS
OGS, and the Lniversity of Toronto Open Fellowship.
1 am deeply grateful to my wonderful family for their never-ending care.
Contents
Abstract ii
Acknowledgement s iii
Contents iv
List of Abbreviations and Acronyms viii
List of Mat hematical Terrns x
List of Figures xii
List of Tables xv
Int roductioa 1
1.1 Overviem of CDMA Cellular Systems . . . . . . . . . . . . - . . . . . . . . 1
1.1.1 MultipleAccess. . . . . . . . . . . . . . . . . . . . . . . . . . . - . 3
1.1.2 Mobile Radio Propagation . . . . . . . . . . . . . . . . . . . . . . . 4
1.1.3 Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
-
1 1 S patial Reuse . . . . . . . . . . . . . . . . . . . . . . . . . . - . . . 3
1.1.5 Wideband CDMA Systems . . . . . . . . . . . . . . . . . . . . . . . 6
-
1 -2 Radio Resource .~llocaito n . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
1.3 Motivation and Thesis Outiine . . . . . . . . . . . . . . . . . . . . . . . . . 9
- 4 Thesis Contribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2 Channel Access Control Schemes for Integrated Services 16
2.1 fntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.2 System hlodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.2.1 Cellular System Mode1 . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.1.2 Traffic Mode1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2.3 Interference Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3 VSG-CDLIA System Capacity . . . . . . . . . . . . . . . . . . . . . . . . . '20
2.3.1 Interference Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.3.2 Bit Error Probability Analysis . . . . . . . . . . . . . . . . . . . . . 24
2.4 Numerical Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.4.1 Mean and Variance of Inter-ce11 Interference . . . . . . . . . . . . . 28
2.4.2 Capacity of the Systeni with Voice and Data Csers . . . . . . . . . 29
2.4.3 Capacity of the System with Low Data Rate and High Data Rate
2.3 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3 Rate Allocation and Scheduling Schemes 39
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.2 System Mode1 and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.2.1 CellularSystem'1Iodel . . . . . . . . . . . . . . . . . . . . . . . . . 42
3-22 Time-Slot ted Structure and Transmission Modes . . . . . . . . . . . 4.3
3.2.3 Traffic Mode1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
3.2.4 Rate and Powr .i llocations . . . . . . . . . . . . . . . . . . . . . . 45
3.3 Scheduling Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.3.1 Scheduling Schemes for TDM Mode Transmission . . . . . . . . . . 49
3.3.2 Scheduling Schemes for CDM Mode Transmission . . . . . . . . . . 52
3.3.3 Impiement ation of Rate and Ponrer Allocations . . . . . . . . . . . . 36
--
3.4 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a
4
..
3.4.1 Effect of Shadowing . . . . . . . . . . . . . . . . . . . . . . . . . . . a
t
3.4.2 Transmission Backoff Probabiiity and Performance Trade-off . . . . 59
3.4.3 Performance Cornparison of Scheduling Schemes . . . . . . . . . . . 69
3.5 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
4 Transmission Time Coordination Among Base Stations 67
-4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
4.2 Systern Mode1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.3 Dynamic Time Coordination: Comple'aty and Effectiveness . . . . . . . . Cl
1.3.1 Complexity of Dynamic Schemes . . . . . . . . . . . . . . . . . . . 72
4.3.2 Effectiveness of Various Schemes . . . . . . . . . . . . . . . . . . . . -t.a-
4.4 Time Coordination Schcmes . . . . . . . . . . . . . . . . . . . . . . . . . . LrIr
--
4.4.1 Fixed Time Share .-\llocation (FTSA) . . . . . . . . . . . . . . . . . r r
4.4.2 Dynamic Time share .-\l location (DTSA) . . . . . . . . . . . . . . . 79
4.5 SimulationResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 ;
4.51 Time Reuse Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . 85
4.3.3 Range of Time Share .4 llocations . . . . . . . . . . . . . . . . . . . 87
-1.5.3 Algori t hni Execution Time . . . . . . . . . . . . . . . . . . . . . . . 85
4 .5 .4 Enhancenients to the DTSA-AIg . . . . . . . . . . . . . . . . . . . . 89
4.6 ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
4.7 Appendix A: A Numerical Example . . . . . . . . . . . . . . . . . . . . . . 90
5 Time Slot Allocation Schemes 93
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
5.2 System Mode1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4
3 Channel Allocation Schernes . . . . . . . . . . . . . . . . . . . . . . . . . . 95
5.4 Unified Channel -1llocati on (UCA) Scheme . . . . . . . . . . . . . . . . . . 97
5.41 Virtual Channel Set (VCS). . . . . . . . . . . . . . . . . . . . . . . 98
5.5 Performance Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
5 1 Simulation Parameters . . . . . . . . . . . . . . . . . . . . . . . . . 100
5-52 lmplernentation of Channel Assignment Scliemes . . . . . . . . . . . IO1
5.5.3 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
5-54 Irnplenientation Issues . . . . . . . . . . . . . . . . . . . . . . . . . 107
5.6 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
6 Conciusions 110
6.1 Thesis Surnrnary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
6.2 FutureCVork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Il4
Bibliography 116
List of Abbreviations and Acronyms
AMPS advanced mobile phone system
AR$ automatic repeat request
BER bit error rate
CDF cumulative distribution function
CDM code division multiplexing
CDMA code division multiple access
DCA dyn amic channel allocation
DTSA dynamic time share allocation
DTSA-Alg dynamic time share allocation-aigorithm
DS direct sequence
ER equal rate
EP eqiial power
FDD frequency division duplex
FEC fonvard error correct ion
FF fastest first
FCA fked channel allocat ion
FTSA fixed time share allocation
FTSA-A1g hed time share allocat ion-aigorit hm
FDMA irequency division multiple access
IP internet protocoi
MAI multiple access interference
MC-CDMA mu1 t i code-code division multiple access
MTSO mobile t elephone swit ching office
PN pseudo noise
QoS quality of senrice
RR round robin