The Effect of Exerting Adequate Persistence in Collision Avoidance Protocols
CALIFORNIA UNIV SANTA CRUZ DEPT OF COMPUTER ENGINEERING
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Many medium-access control MAC protocols based on a collision-avoidance handshake between the sender and the receiver have been proposed for wireless networks. To date, however, the analysis of these protocols has assumed non-persistent strategies in sending control packets for collision avoidance. The persistent strategies discussed in the past for CSMA and CSMACD provide performance improvements over non-persistent access only at small traffic loads. We present and analyze a limited persistence approach to the transmission of collision-avoidance control packets. With limited persistence, a node senses the channel before sending collision-avoidance control packets. If the channel is sensed busy, the node persists sensing for an amount of time proportional to the transmission time of a control packet. The node can transmit its control packet if the channel is idle within its persistence waiting time and the channel is known to be available for transmissions otherwise, the node backs off for a random amount of time and tries sending its control packet at the end of that time. We analyze the effect of limited persistence in source-initiated and receiver-initiated collision avoidance protocols by comparing their throughput with and without persistence the analysis shows that limited persistence makes collision-avoidance protocols more efficient.
- Computer Systems Management and Standards
- Radio Communications