Collision Avoidance and Recovery for Multicast Communications in Ad Hoc Networks

Kwan Shek LAU  Derek C.W. PAO  

IEICE TRANSACTIONS on Communications   Vol.E88-B   No.7   pp.2937-2943
Publication Date: 2005/07/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.7.2937
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
medium access control,  collision avoidance,  receiver-initiated recovery,  multicast,  wireless ad hoc networks,  

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The basic carrier sense multi-access control scheme for multicast communications in wireless ad hoc networks suffers from the well know hidden terminal problem. The data packet collision probability is relatively high, and the packet delivery ratio is sensitive to the network topology, nodes distribution and traffic load. In this paper, we generalize the virtual carrier sense collision avoidance approach to reduce packet collisions in multicast communications. The sender and receivers exchange RTS and CTS packets to reserve the channel. When more than one receivers reply with CTS packets, the sender will detect an "expected" collision which may be interpreted as a valid "clear-to-send" signal provided the collision satisfies the given timing requirements. Together with a receiver-initiated local recovery mechanism, the reliability and packet delivery ratio can be improved to close to 100%.