Revenue Maximization in Resource Allocation

226 Pages·2012·7.73 MB·English

Nilo Casimiro Ericsson
Revenue Maximization
in Resource Allocation:
Applications in Wireless
Communication Networks
October 2004
SIGNALS AND SYSTEMS
UPPSALA UNIVERSITY
UPPSALA, SWEDEN
c Nilo Casimiro Ericsson, 2004
(cid:176)
ISBN 91-506-1773-7
Printed in Sweden by Eklundshofs Graflska, Uppsala, 2004
Till min ˜angel
Abstract
Revenue maximization for network operators is considered as a criterion
for resource allocation in wireless cellular networks. A business model en-
compassing service level agreements between network operators and service
providers is presented. Admission control, through price model aware ad-
mission policing and service level control, is critical for the provisioning of
useful services over a general purpose wireless network. A technical solution
consisting of a fast resource scheduler taking into account service require-
mentsandwirelesschannelproperties,aservicelevelcontrollerthatprovides
the scheduler with a reasonable load, and an admission policy to uphold the
service level agreements and maximize revenue, is presented.
Two difierent types of service level controllers are presented and imple-
mented. One is based on a scalar PID controller, that adjusts the admitted
data rates for all active clients. The other one is obtained with linear pro-
gramming methods, that optimally assign data rates to clients, given their
channel qualities and price models.
Two new scheduling criteria, and algorithms based on them, are presented
and evaluated in a simulated wireless environment. One is based on a
quadratic criterion, and is implemented through approximative algorithms,
encompassing a search based algorithm and two difierent linearizations of
the criterion. The second one is based on statistical measures of the service
rates and channel states, and is implemented as an approximation of the
joint probability of achieving the delay limits while utilizing the available
resources e–ciently.
Twoschedulingalgorithms, onebasedoneachcriterion, aretestedincom-
bination with each of the service level controllers, and evaluated in terms of
throughput, delay, and computational complexity, using a target test sys-
tem. Results show that both schedulers can, when feasible, meet explicit
throughputanddelayrequirements, whileatthesametimeallowingtheser-
vice level controller to maximize revenue by allocating the surplus resources
to less demanding services.
Acknowledgments
First of all, my supervisors Professor Anders Ahl¶en and Professor Mikael
Sternad, deserve my greatest gratitude for sharing their enthusiasm, knowl-
edge, and experience, but also for pushing me forward in times of less
progress. It has been fun and interesting to work with you, and I hope
that we continue our work together in the same familiar spirit. Thanks also
toallthepeopleintheSignals&SystemsgroupatMagistern, thatalsocon-
tribute to the stimulating atmosphere, and especially to Mathias Johansson
for also proof-reading parts of this thesis.
The work is supported by the Swedish Foundation of Strategic Research,
through the PCC (Personal Computing and Communications) research pro-
gram. Within PCC, the Wireless IP (WIP) project develops innovative
approaches to increase spectrum e–ciency and throughput for data over
wireless links.
Familyand friends makethe efiort worthwile. I’mglad Ihave you to share
the good times, and the not so good times, with.
Finally, I want to acknowledge the huge support from Jenny, my partner
for life. There has to be a meaning with the things that you do every day,
and to me, Jenny has brought that, and much more.
For you who read my licentiate thesis -
here’s the sequel, and it’s better!

Contents
1 Introduction 1
1.1 Contributions and Outline . . . . . . . . . . . . . . . . . . . . 2
1.2 Mapping Application Requirements onto Service Requirements 3
1.2.1 Internet Protocol . . . . . . . . . . . . . . . . . . . . . 5
1.2.2 Service Level Control in IP: IntServ and DifiServ . . . 6
1.3 Resources and Capacity . . . . . . . . . . . . . . . . . . . . . 6
1.3.1 Partition of the Resources . . . . . . . . . . . . . . . . 7
1.3.2 E–cient Use of the Resources . . . . . . . . . . . . . . 8
1.4 Scheduling and Admission Control . . . . . . . . . . . . . . . 9
1.4.1 Common Objectives for Link Schedulers . . . . . . . . 9
1.4.2 A Framework for Service Level Control over Wireless
Networks . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Revenue - the Criterion 13
2.1 Who Are the Actors?. . . . . . . . . . . . . . . . . . . . . . . 14
2.1.1 Deployment . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1.2 Operation . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.1.3 Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.2 Business Models . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.2.1 Single Service Provider. . . . . . . . . . . . . . . . . . 17
2.2.2 Multiple Service Providers . . . . . . . . . . . . . . . . 17
2.2.3 Advantages of Having Multiple Service Providers on
One Network . . . . . . . . . . . . . . . . . . . . . . . 19
2.3 Revenue from Operation . . . . . . . . . . . . . . . . . . . . . 21
2.3.1 Service Difierentiation . . . . . . . . . . . . . . . . . . 21
2.3.2 Service Level Agreement . . . . . . . . . . . . . . . . . 21
v
vi Contents
2.3.3 Pricing Models . . . . . . . . . . . . . . . . . . . . . . 25
2.3.4 Business Models and Pricing Today . . . . . . . . . . 30
2.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3 Admission Control 37
3.1 Overview and Notation . . . . . . . . . . . . . . . . . . . . . 38
3.2 Admission Policing . . . . . . . . . . . . . . . . . . . . . . . . 40
3.2.1 Implementation of an Admission Policy . . . . . . . . 43
3.3 Service Level Control . . . . . . . . . . . . . . . . . . . . . . . 45
3.3.1 Service Level Control as a Linear Control Problem . . 47
3.3.2 Service Level Control as a Mathematical Program-
ming Problem . . . . . . . . . . . . . . . . . . . . . . . 51
3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4 Scheduling 55
4.1 Motivations for the Use of Scheduling . . . . . . . . . . . . . 56
4.1.1 Motivation 1: Improving Spectrum E–ciency . . . . . 56
4.1.2 Motivation 2: Fulfllling Service Requirements . . . . . 56
4.1.3 Motivation 3: Channel Prediction Works. . . . . . . . 57
4.2 Optimization of Resource Allocation . . . . . . . . . . . . . . 57
4.2.1 Channel Constraints . . . . . . . . . . . . . . . . . . . 58
4.2.2 Service Requirements . . . . . . . . . . . . . . . . . . 60
4.2.3 Complexity . . . . . . . . . . . . . . . . . . . . . . . . 62
4.3 A Scheduled Communication System . . . . . . . . . . . . . . 62
4.3.1 Channel Estimation . . . . . . . . . . . . . . . . . . . 63
4.3.2 Channel Prediction . . . . . . . . . . . . . . . . . . . . 64
4.3.3 Downlink Channel Quality Signalling. . . . . . . . . . 65
4.3.4 Downlink and Uplink Schedule Signalling . . . . . . . 67
4.3.5 Conclusions and Outline of a Proposed System . . . . 68
5 Scheduling Algorithms 71
5.1 Deflnitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.2 Wireline Fair Scheduling Algorithms . . . . . . . . . . . . . . 72
5.2.1 Generalized Processor Sharing (GPS) . . . . . . . . . 72
5.2.2 Weighted Fair Queueing (WFQ) . . . . . . . . . . . . 74
5.2.3 Worst-case Fair Weighted Fair Scheduling (WF2Q) . . 74
5.2.4 Round Robin (RR) . . . . . . . . . . . . . . . . . . . . 75
5.2.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.3 Wireless Fairness Throughput Scheduling Algorithms . . . . . 76
5.3.1 Proportional Fair Scheduling (PF) . . . . . . . . . . . 76
Contents vii
5.3.2 Score Based Scheduling (SB) . . . . . . . . . . . . . . 77
5.3.3 CDF-based Scheduling (CS) . . . . . . . . . . . . . . . 78
5.4 Wireless QoS Scheduling Algorithms . . . . . . . . . . . . . . 78
5.4.1 Modifled Proportional Fair Scheduling (MPF) . . . . . 79
5.4.2 Modifled Largest Weighted Delay First (M-LWDF) . . 80
5.4.3 Exponential Rule (ER) . . . . . . . . . . . . . . . . . 81
5.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6 Power-n Scheduling Criteria 85
6.1 The Quadratic Scheduling Criterion . . . . . . . . . . . . . . 88
6.1.1 The Weighting Factor . . . . . . . . . . . . . . . . . . 90
6.2 Linearization of the Quadratic Criterion . . . . . . . . . . . . 94
6.2.1 Alternative Derivation 1: Difierentiation . . . . . . . . 95
6.2.2 Alternative Derivation 2: Taylor expansion . . . . . . 96
6.3 Algorithms based on the Quadratic Criterion . . . . . . . . . 97
6.3.1 Motivation of Difierent Linear Algorithms . . . . . . . 97
6.3.2 Non-updated Linear Algorithm (MAXR) . . . . . . . 99
6.3.3 Updated Linear Algorithm (ITER) . . . . . . . . . . . 99
6.3.4 Controlled Steepest Descent (CSD) . . . . . . . . . . . 101
6.3.5 Summary of Computational Complexity . . . . . . . . 102
6.3.6 Deviations from Optimum by the Approximations . . 104
6.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
7 Probability based Scheduling Criteria 111
7.1 Probability of Service Failure . . . . . . . . . . . . . . . . . . 113
7.1.1 Delay Requirements . . . . . . . . . . . . . . . . . . . 113
7.1.2 Jitter Requirements . . . . . . . . . . . . . . . . . . . 117
7.2 Probability of a Good Resource . . . . . . . . . . . . . . . . . 119
7.3 Combining the Probabilities . . . . . . . . . . . . . . . . . . . 121
7.4 Probabilistic Criterion Algorithms . . . . . . . . . . . . . . . 122
7.4.1 The CDF Based Scheduling Algorithm (CBS) . . . . . 122
7.4.2 The Score Based Scheduling Algorithm (SBA) . . . . 124
7.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8 Simulations 129
8.1 Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
8.1.1 Data Tra–c . . . . . . . . . . . . . . . . . . . . . . . . 130
8.1.2 Wireless Transmission . . . . . . . . . . . . . . . . . . 130
8.1.3 Control Signalling . . . . . . . . . . . . . . . . . . . . 130
8.2 Channel Models . . . . . . . . . . . . . . . . . . . . . . . . . . 131
viii Contents
8.2.1 General Channel Model . . . . . . . . . . . . . . . . . 131
8.2.2 Non-correlated Rayleigh Channels . . . . . . . . . . . 133
8.2.3 Real-world Fading Channels . . . . . . . . . . . . . . . 134
8.2.4 Emulated Channels. . . . . . . . . . . . . . . . . . . . 135
8.3 Scheduling Based on the Quadratic Criterion . . . . . . . . . 136
8.3.1 Non-correlated Rayleigh Fading Channel Model . . . . 138
8.3.2 Performance in the Presence of Correlation in Time
and Frequency . . . . . . . . . . . . . . . . . . . . . . 144
8.3.3 Flat and Static Channels . . . . . . . . . . . . . . . . 151
8.3.4 Service Level Control as a Linear Program . . . . . . 153
8.4 Probability Based Scheduling Algorithm . . . . . . . . . . . . 153
8.4.1 Performance in the Presence of Correlation in Time
and Frequency . . . . . . . . . . . . . . . . . . . . . . 154
8.4.2 PID Service Level Control . . . . . . . . . . . . . . . . 155
8.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
9 Case Study 159
9.1 Mobile Environment . . . . . . . . . . . . . . . . . . . . . . . 160
9.2 Service Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
9.3 ITER Scheduling and PID-based Service Level Control . . . . 163
9.3.1 PID controller . . . . . . . . . . . . . . . . . . . . . . 163
9.3.2 ITER Scheduling Controlling Bufier Levels . . . . . . 164
9.3.3 ITER Scheduling with Saturated Service Level Control169
9.3.4 Controlling Bufiers with More Flexible Clients . . . . 171
9.3.5 ITER Scheduling Controlling Delays . . . . . . . . . . 172
9.3.6 PID SLC with Slower Sampling . . . . . . . . . . . . . 174
9.3.7 Conclusions from ITER Scheduling with PID SLC . . 175
9.4 SBA Scheduling and PID Service Level Control . . . . . . . . 175
9.4.1 PID Controller . . . . . . . . . . . . . . . . . . . . . . 175
9.4.2 SBA Scheduling Controlling Delays . . . . . . . . . . . 176
9.4.3 PID SLC with Slower Sampling . . . . . . . . . . . . . 177
9.4.4 Conclusions from SBA Scheduling with PID SLC . . . 180
9.5 SBA Scheduling with Linear Program SLC . . . . . . . . . . 180
9.5.1 Linear Program . . . . . . . . . . . . . . . . . . . . . . 180
9.5.2 LP SLC Without Bufier Level Rate Correction . . . . 182
9.5.3 LP SLC With Bufier Level Rate Correction . . . . . . 183
9.6 ITER Scheduling with Linear Program SLC . . . . . . . . . . 185
9.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
10 Conclusions and Future Work 187