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AN INVESTIGATION INTO THE ADVANCED 
TIME DIVISION MULTIPLE ACCESS(ATDMA) 

PROTOCOL FOR A PERSONAL 
COMMUNICATION NETWORK 

This thesis is presented in partial fulfilment of the requirements for 
the degree of Master of Technology in Information Engineering at 

Massey University. 

YIFANLI 

1997 



CONTENTS 

Abstract ... ...................... .. ........................... ........... ...... .. ................. .................... ....... . V 

Acknowledgments .... ... ................. .... ...... .. .... ..... ... .......... ... .... ... .. .............................. .. VI 

CHAPTER I INTRODUCTION 

1.0 General Introduction .. .... .... .. .. ...... ....................... .. ..... ... .. .. ....... ..... ... .. ............. 1 

1.1 Thesis Structure ...... .. ........ ... .. .. ....... .. .................. ........................................ .. .. 3 

CHAPTER II OVERVIEW OF MULTIPLE ACCESS PROTOCOLS FOR 
CELLULAR WIRELESS NETWORKS 

2.0 Introduction .......... .. ....... ...... ......................... ........ ........... ............ ............ .......... 5 

2.1 Cellular wireless networks ............ .. .. ....... ...... .... .. .................... ....................... .. 6 

2.1.1 Cellular concept and frequency reuse ..... .. .......... .. .... .. ............ ...... .. ...... 6 

2.1.2 Interference and system capacity .......... .... ........... .... .. ......................... .. 11 

2.1.3 Development of wireless networks .... ..... .. .. .. ...... .. .. ... .... .. .. .. ...... .. .. ....... 14 

2.1 .4 Wireless LANs ..... ........ .. ........ ...... ............................................... .. ....... 16 

2.2 Classification of multiple access protocols .... .. ...................................... .... .. ..... 20 

2.3 Multiple access protocols for mobile radio ....................................................... 22 

2.3 .1 Pure ALOHA ................................... ..................................................... 22 

2.3.2 Slotted ALOHA ....................... .... .. .... .. .................................. ...... ...... ... 23 

2.3 .3 TM-BCMNCD ... .... ... .... ..... .... .... ... ..... ... ... .... ..... .. .. .. .. .... ... .. ... ... .......... . 24 

2.3.4 The Frequency Division Multiple Access (FDMA) ...... .. ..................... 26 

2.3.5 Time Division Multiple Access (TDMA) ............................................ 26 

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2.3.6 Code Division Multiple Access (CDMA) ..... ...... ................ .......... .... ... 28 

2.3.7 R-ALOHA .............. ............................................ ......... .. ... ..... ..... ... ....... 31 

2.3.8 Packet Reservation Multiple Access (PRMA) ..................................... 32 

2.3.9 Advanced Time Division Multiple Access (ATDMA) ....................... . 34 

2.4 Discussion and comparison ..... ............... ..... .. ... ............ ...... ........... ................. ... 35 

2.5 Conclusion .................. ....................... ..... ............. ....... ...... .... ........................ ... . 37 

CHAPTER III ATDMA AIR INTERFERENCE IN A MICROCELL 
ENVIRONMENT 

3. 0 Introduction ........................................................... .... ... ......... .. .. ....... ... .... .. .. .... .. 3 8 

3.1 ATDMA protocol structure and system requirements .. .. .... .... .. ........ ... ........ ..... 39 

3.1.l ATDMA protocol structures ...................... ..... .... ........ .............. ............ 39 

3.1 .2 ATDMA operating environments .. ... ..... ....... ..... ...... ..... ......... ..... .. ..... .. .43 

3.1.3 Service supported by an ATDMA system .... ... ......... ..... ... ... .. ...... ... .. .. . .43 

3.1.4 Duplexing choice ... ......... ............ .................... ......... ............. .... ........ .... 45 

3.1.5 Adaptive air interface ..... ... .. .. .. ... ...... ....... ....... .... ......... ......... .. .. .... ........ 45 

3 .1.5 .1 Adaptive to cell type .... ... .... ...... ...... ... ....................... ....... ...... 46 

3.1.5.2 Adaptive to user/traffic ...... ..... .. .. ..... .... ...... .. ......... .. .. ....... ..... .46 

3.1.5.3 Adaptive to interference ... ...................................... ... ... .. .... .. .. 47 

3.1.5.4 Adaptive to source activity ....... ....... ......... ............. ... ... ..... .. .. .48 

3.2 ATDMA functional model.. .......................... ........... .............. ........................... 49 

3.3 Advantage of the ATDMA protocol ............................ ................................ ..... 52 

3 .4 Microcells in personal communication systems ..................................... .......... 5 3 

3.4.1 Radio propagation ... .. .. .... ................... ...... ..... ........................... ..... ....... 55 

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3.4.2 Multiple fading ..................................................................................... 56 

3.4.3 Local movement and Doppler spread ...... ..................................... .. .. .... 58 

3.4.4 Shadowing and path loss ...................................................................... 60 

3.4.5 Time dispersion ....................... .. ................. .... .......... ..... ... ... ..... .. .......... 62 

3.4.6 Channel modelling technique ............................................................... 65 

3 .5 Conclusion .... ......... .. ....................... ... ....... ................................... ... ..... ............. 67 

CHAPTER IV PERFORMANCE OF THE ATDMA PROTOCOL IN A 
CELLULAR RADIO ENVIRONMENT 

4.0 Introduction .... .... ... ... ... ... ....... ......... ............. ................ ... .. .. .............. ........... ...... 69 

4.1 The microcell channel model ............................................................................ 70 

4.1.1 An area-to-area path loss prediction model .... ... ........ ..... .. ........ ..... ..... .. 70 

4.1.2 The microcell prediction model.. .......................................................... 74 

4.1.3 Carrier-to-interference analysis of the microcell prediction model ...... 77 

4.2 Simulation of the ATDMA protocol.. .... ......................... ...................... ... .... ...... 81 

4.3 Validation of simulation mode .................................................... . .... 91 

4.4 Simulation results .................. .... ..... ....... ..................... ...... ...... .............. ......... .... . 92 

4.5 Conclusion ........................................................................................................ 106 

CHAPTERV OVERALL CONCLUSION AND SUGGESTION FOR 
FUTURE WORK 

5. 0 Overall conclusion and suggestion for future work .............................. .... ........ 108 

III 



REFERENCES ........ .... ... .. .... ...... .. ..... ... .... ...... ... .. .... ...... ... .... ..... .... ... ... ... ................. . 113 

APPENDIX 

A SIMULATION PROGRAM FOR THE ADVANCED TIME 
DIVISION MULTIPLE ACCESS (ATDMA) PROTOCOL IN A 
MICROCELL ENVIRONMENT .... ..... ... .............. ..... ........ .... ...... ... .... .... ... 120 

IV 



ABSTRACT 

The performance of the Advanced Time Division Multiple Access (ATDMA) 

protocol in a microcell environment has been investigated in this thesis. The ATDMA 

protocol is a new generation protocol which can support both circuit switched and 

packet switched transmission modes. The protocol can also adapt in a varying 

propagation environment. This thesis examines the efficiency of the protocol in a 

microcell environment and also examines different access techniques for voice and 

data traffic to improve the efficiency of the protocol. To study the performance of the 

protocol a discrete event based simulation model has been developed which includes a 

microcell channel model of a city area. 

A data block reservation scheme has been developed in this work, which increase the 

traffic efficiency of the protocol. By combining the data block reservation scheme and 

capture effect, the ATDMA protocol's performance in transmitting mixed voice and 

data traffic in an urban microcell environment was investigated by means of computer 

simulation. The simulation model was used to find out the appropriate parameters for 

the optimum performance of the protocol and then to investigate the performance of 

the protocol. With consideration of the capture ratio, the effect of capture has also 

been evaluated in a more practical manner. 

V 



ACKNOWLEDGMENTS 

I would like to express my appreciation to my supervisor Dr. Jamil Y. Khan, for his 
continuous guidance, advice and encouragement throughout this research work. 

I am also grateful to Professor RM. Hodgson for his interest and encouragement 
during this study. 

I wish to thank my great friend Noel Harris who has in the last weeks proofread the 
thesis. 

My sincere thanks also goes to all those who helped me directly or indirectly in the 
completion of this research work. 

Finally, I thank my wife, Lin, and my son, Mochi, for their understanding and 
encouragement. 

VI