Radio Resource Sharing and Bearer Service Allocation for Multi

170 Pages·2003·1.82 MB·English

Radio Resource Sharing and Bearer Service
Allocation for Multi-Bearer Service,
Multi-Access Wireless Networks
–

Methods to Improve Capacity

Anders Furuskär

RADIO COMMUNICATION SYSTEMS LABORATORY

Radio Resource Sharing and Bearer Service
Allocation for Multi-Bearer Service,
Multi-Access Wireless Networks
–

Methods to Improve Capacity

Anders Furuskär

A dissertation submitted to the Royal Institute of Technology
in partial fulfillment of the requirements for the degree of Doctor of Philosophy

May 2003

TRITA-S3-RST-0302
ISSN 1400-9137
ISRN KTH/RST/R--03/02--SE

RADIO COMMUNICATION SYSTEMS LABORATORY
DEPARTMENT OF SIGNALS, SENSORS AND SYSTEMS

Abstract
Two expected characteristics of future wireless networks are support for multiple bearer ser-
vices, which in turn enable multiple end-user services, and the parallel use of multiple radio
access technologies. This dissertation discusses radio resource management principles to im-
prove capacity for such multi-bearer service, multi-access networks.
More specifically, it is first focused on how to most efficiently share the radio resource be-
tween bearer service groups within one access technology. A general principle for sharing
resources in interference limited systems is proposed, and its expected performance esti-
mated. The proposed interference balancing principle maximizes capacity by adjusting the
power budgets per bearer service group so that the maximum tolerable interference levels are
equal for all bearer services. To verify its validity, the interference balancing principle is ap-
plied to the 3rd generation cellular systems GSM/EDGE and WCDMA in a set of multi-
bearer service case studies. It is seen that interference balancing may straightforwardly be
introduced in these systems, and that significant capacity gains over non-balanced scenarios
can be achieved.
Secondly, how to best share traffic load between the different sub-systems in a multi-access
scenario is investigated. The capability to handle bearer services, and thereby also end-user
services, typically differs between sub-systems. The overall multi-access system capacity is
therefore affected by the allocation of bearer services on to sub-systems. Based on this, a
simple principle for finding favorable, under certain constraints near-optimum, sub-system
bearer service allocations is derived. It is seen that for a given service mix combined capaci-
ties beyond the sum of the sub-system capacities may be achieved by using the favorable
bearer service allocations. Significant capacity gains are also seen in a case study in which
the bearer service allocation principle is applied to a combined GSM/EDGE and WCDMA
multi-access system. The bearer service type may be said to reflect an expected radio re-
source cost for supporting a user in each sub-system. By taking into account the actual radio
resource cost, which may differ from the expected cost, when assigning users to sub-
systems, further capacity gains are achievable.

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Acknowledgements
This dissertation exists thanks to the support of many people to whom I am most grateful. I
first wish to thank my colleagues at the Radio Communication Systems Laboratory at the
Royal Institute of Technology for valuable contributions. Especially acknowledged is the
always relevant and accurate guidance from my main advisor Professor Jens Zander. I’m
also most thankful for the valuable reviews and comments of Assistant Professors Tim Giles
and Ben Slimane, as well as for the administrative assistance of Lise-Lotte Wahlberg.
The advising I’ve enjoyed from colleagues outside the Royal Institute of Technology, fore-
most my industrial advisor at Ericsson Research Sverker Magnusson is greatly appreciated.
The careful reviews provided by Magnus Frodigh, Harri Posti, and Birgitta Olin have also
been of great value. Further, the many discussions with colleagues Magnus Almgren, Arne
Simonsson, and Henrik Nyberg have contributed considerably to the material of this disser-
tation. Moreover, the great deal I have learnt from working together with Peter de Bruin,
Christer Johansson, Stefan Jäverbring, and Håkan Olofsson, together with the support of
Tommy Ljunggren, have significantly aided in carrying out this work.
I wish to warmly thank Lovisa and my parents for love and encouragement.
Financing from the Swedish Research Council and Ericsson Research is of course greatly
valued. At Ericsson the efforts of Håkan Eriksson, Magnus Madfors, and Sara Mazur associ-
ated with this are well worth acknowledging.

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Contents

Chapter 1 Introduction 1
1.1 Multi-Bearer Service, Multi-Access Wireless Networks.............................1
1.2 Related Work...............................................................................................4
1.3 Problem Formulation, Focus and Motivation..............................................7
1.4 Original Contributions.................................................................................9
1.5 Dissertation Outline...................................................................................12
Chapter 2 Multi-Bearer Service, Multi-Access Wireless Networks Fundamentals 13
2.1 Wireless Network Fundamentals...............................................................13
2.2 IMT-2000 Systems Service and Architecture Overview...........................15
2.3 Basic Radio Access Network Principles....................................................16
2.4 Multi-Access Wireless Networks..............................................................18
Chapter 3 System Models and Performance Measures 19
3.1 Performance Measuring and Modeling Approaches..................................19
3.2 Traffic Load and Service Mix....................................................................21
3.3 User and System-Level Quality.................................................................22
3.4 Multi-Bearer Service Quality, Capacity and Capacity Regions................22
3.5 Normalized Measures................................................................................23
3.6 Multi-Access Combined Capacity and Capacity Regions.........................25
3.7 Valuing Bearer Services.............................................................................28
Chapter 4 Radio Resource Sharing in Multi-Bearer Service Interference Limited
Wireless Networks 29
4.1 Per-Service Capacity Balancing................................................................29
4.2 Interference Balancing...............................................................................33
4.3 Expected Performance...............................................................................36
4.4 Applicability of the Results.......................................................................45
4.5 Summary....................................................................................................47
Chapter 5 Multi-Bearer Service Case 1 – Voice and WWW in GSM/EDGE 49
5.1 GSM/EDGE Overview..............................................................................49
5.2 Interference Balancing in GSM/EDGE......................................................53
5.3 Models, Assumptions and Analysis Technique.........................................54
5.4 Numerical Results......................................................................................63
5.5 Summary....................................................................................................69
Chapter 6 Multi-Bearer Service Case 2 – WCDMA with SIR-balancing Power
Control 71
6.1 WCDMA Overview...................................................................................71
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6.2 Interference Balancing in WCDMA..........................................................74
6.3 Models and Assumptions...........................................................................75
6.4 Numerical Results......................................................................................78
6.5 Summary....................................................................................................81
Chapter 7 Multi-Bearer Service Case 3 – Voice and WWW in WCDMA/HSDPA 83
7.1 HSDPA Overview......................................................................................83
7.2 Interference Balancing in WCDMA/HSDPA............................................84
7.3 Models and Assumptions...........................................................................85
7.4 Numerical Results......................................................................................88
7.5 Summary....................................................................................................92
Chapter 8 Multi-Bearer Service Allocation in Multi-Access Wireless Networks 93
8.1 Information Availability Scenarios............................................................93
8.2 Bearer Service Allocation Strategies.........................................................94
8.3 Some Simple Illustrative Examples...........................................................98
8.4 Implementation Aspects...........................................................................100
8.5 Applicability of the Results.....................................................................101
8.6 Summary..................................................................................................101
Chapter 9 Multi-Access Case 1 – GSM/EDGE and WCDMA/HSDPA 103
9.1 Underlying Results...................................................................................103
9.2 Resulting Bearer Service Allocations and Capacity Regions..................104
9.3 Summary..................................................................................................106
Chapter 10 User Assignment in Multi-Access Wireless Networks 109
10.1 Additional System Models and Selection Variables................................109
10.2 Load Balancing........................................................................................111
10.3 User Assignment Algorithms...................................................................112
10.4 Expected Radio Resource Costs..............................................................115
10.5 Evaluation Methodology..........................................................................116
10.6 Numerical Results....................................................................................116
10.7 Summary..................................................................................................119
Chapter 11 Conclusions 123
11.1 How to Share Resources between Bearer Services?................................123
11.2 How to Allocate Bearer Services onto Sub-Systems?.............................124
11.3 Further Studies.........................................................................................125
References 127
Appendix A Abbreviations and Acronyms 137
Appendix B Asymptotic Behavior of Trunking and Diversity Gains 139
Appendix C The Effect of Requiring Equal Sub-System Qualities 147
Appendix D Per-Service Capacity and Interference Balancing Proofs 149
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