A Random Access Micro-Cellular System Based on CSMA and Power Control

Satoru KUBOTA  Kouichi MUTSUURA  Osamu AKIZUKI  Shinjirou OOSHITA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E81-A   No.7   pp.1349-1357
Publication Date: 1998/07/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Fundamentals of Multi-dimensional Mobile Information Network)
random access,  micro-cellular,  RAMCS,  CSMA,  throughput,  

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A random access micro-cellular system based on CSMA (RAMCS/CSMA) is proposed. On uplink in RAMCS/ CSMA, packets are transmitted by means of CSMA at the same carrier frequency in any cell. On downlink, packets are broadcast conforming to TDMA, also at the same carrier frequency in any cell. In RAMCS/CSMA, deployed microcells produce higher system capacity. Nevertheless, " handoff on a terminal " isn't required. In this paper, overview of the system, fundamental uplink performance, and two kinds of power control methods are presented. As for the control methods, one is control according to packet priority. The other is a way according to location of a mobile terminal. By means of CSMA, throughput performance on uplink becomes great and is saturated at 0. 39 per cell. And the performance strongly depends on the threshold level on carrier sense. Such a throughput performance is peculiar to RAMCS/CSMA and different from an ordinary CSMA system. The optimum threshold is also indicated here. Furthermore, it is clarified that both power control methods highly improve the throughput performance. As a result, it is found that RAMCS/CSMA is excellent for mobile communications.