Centralized Channel Allocation Technique to Alleviate Exposed Terminal Problem in CSMA/CA-Based Mesh Networks--Solution Employing Chromatic Graph Approach--


IEICE TRANSACTIONS on Communications   Vol.E88-B    No.3    pp.958-964
Publication Date: 2005/03/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.3.958
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Ubiquitous Networks)
Category: Network
IEEE 802.11,  mesh network,  multihop transmission,  exposed terminal problem,  TCP,  coloring problem,  

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This paper proposes a channel allocation principle that prevents TCP throughput degradation in multihop transmissions in a mesh network based on the carrier sense multiple access with collision avoidance (CSMA/CA) MAC protocol. We first address the relationship between the network topology of wireless nodes and the TCP throughput degradation based on computer simulations. The channel allocation principle is discussed in terms of resolution into a coloring problem based on throughput degradation. The number of required channels for the proposed channel allocation principle is evaluated and it is shown that two channels are sufficient for more than 96% simulated multihop patterns. The proposed channel allocation principle is extendable to generic mesh networks. We also clarify the number of required channels for mesh networks. The simulation results show that three channels are sufficient for more than 98% patterns in the generic mesh networks when the number of nodes is less than 10.