Deafness: A MAC problem in ad hoc networks when using directional antennas

Romit Roy Choudhury, Nitin H Vaidya

Research output: Contribution to journalConference articlepeer-review


This paper addresses deafness - a problem that appears when MAC protocols are designed using directional antennas. Briefly, deafness is caused when a transmitter fails to communicate to its intended receiver, because the receiver is beamformed towards a direction away from the transmitter. Existing CSMA/CA protocols rely on the assumption that congestion is the predominant cause of communication failure, and adopt backoff schemes to handle congestion. While this may be appropriate for omnidirectional antennas, for directional antennas, both deafness and congestion can be the reason for communication failures. An appropriate directional MAC protocol needs to classify the actual cause of failure, and react accordingly. This paper quantifies the impact of deafness on directional medium access control, and proposes a tone-based mechanism as one way of addressing deafness. The tone-based mechanism, ToneDMAC, assumes congestion as the default reason for communication failures, and applies a corrective measure whenever the cause is deafness. Simulation results indicate that ToneDMAC can alleviate deafness, and perform better than existing directional MAC protocols.

Original languageEnglish (US)
Pages (from-to)283-292
Number of pages10
JournalProceedings - International Conference on Network Protocols, ICNP
StatePublished - Dec 1 2004
EventProceedings of the 12th IEEE International Conference on Network Protocols, ICNP 2004 - Berlin, Germany
Duration: Oct 5 2004Oct 8 2004

ASJC Scopus subject areas

  • Engineering(all)


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