JOURNAL OF NETWORKS (JNW)
ISSN : 1796-2056
Volume : 3    Issue : 8    Date : November 2008

Computational Time-Division and Code-Division Channel Access Scheduling in Ad Hoc Networks
Lichun Bao and J.J. Garcia-Luna-Aceves
Page(s): 26-34
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Abstract
Using two-hop neighborhood information, we present the hybrid activation multiple access (HAMA)
protocol for time-division channel access scheduling in ad hoc networks with omni-directional
antennas. Different from other approaches, HAMA is a node-activation channel access protocol that
also maximizes the chance of link activations using time- and code-division schemes. The
throughput and delay characteristics of HAMA in randomly-generated multihop wireless networks
are studied by analyses and simulations. The results of the analyses show that HAMA achieves
higher channel utilization in ad hoc networks than previous similar works, namely, the node
activation multiple access (NAMA), the link activation multiple access (LAMA) and pair-wise link
activation multiple access (PAMA). In addition, HAMA achieves better throughout than an existing
scheduling algorithm based on complete topology information, and much higher throughout than
the ideal CSMA and CSMA/CA protocols. The main contribution of this work is to computationally
derive channel access schedules according to local network topology information instead of
on-demand negotiations or static global coordinations.

Index Terms
Channel access scheduling, medium access control protocol, MAC, ad hoc networks.