CDMA Unslotted ALOHA Systems with Packet Retransmission Control

Hiraku OKADA  Takeshi SATO  Takaya YAMAZATO  Masaaki KATAYAMA  Akira OGAWA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E79-A    No.7    pp.1004-1010
Publication Date: 1996/07/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Multi-dimensional Mobile Informatin Network)
CDMA unslotted ALOHA,  throughput,  delay,  system stability,  retransmission control,  

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In this paper, we analyze the throughput and delay performances of the CDMA unslotted ALOHA system considering packet retransmisson. We also clarify the stability of the system. Based on these results, we propose the optimal retransmission control (ORC) to improve the performances. The ORC is the scheme to prevent the system from drifting to an undesirable operating point by controlling the birth rate of retransmitted packets. As a result, it is shown that the throughput and delay performances of the system with the ORC are better than without the ORC and the system does not drift to an undesirable operating point.