A New Multi-Channel Mesh Architecture with DCF-Based Inter-AP Communication and Radio-Aware Packet Forwarding for IEEE 802.11-Compliant WLANs

Luis LOYOLA
Tomoaki KUMAGAI
Kengo NAGATA
Shinya OTSUKI
Satoru AIKAWA

Publication
IEICE TRANSACTIONS on Communications   Vol.E90-B    No.1    pp.78-91
Publication Date: 2007/01/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.1.78
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Terrestrial Radio Communications
Keyword: 
multihop networks,  mesh networks,  IEEE 802.11 wireless LAN,  

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Summary: 
The mesh topology based on the standard IEEE 802.11 for wireless LANs (WLANs) appears to be a very promising architecture on the way to realizing an ubiquitous high-speed wireless Internet access in the future. However, the current IEEE 802.11 protocol is aimed at single Access Point (AP) environments and many problems related to the wireless meshed interconnection of APs and Mobile Terminals (MTs) remain unsolved. Some proposed solutions to build such mesh architectures are based on ad-hoc-oriented single-channel schemes that modify IEEE 802.11 protocol. The main problem with this type of schemes, however, lies in the very low performance of the single-channel architecture itself when the network becomes larger or the offered traffic load increases. The task group IEEE 802.11s is currently discussing and working out a standard for IEEE 802.11-compliant mesh architectures for various usage scenarios including residential, office and campus/community/public access network but much work is ahead since the group was recently established. In this paper we propose a new multi-radio multi-channel mesh architecture for WLAN hot spots, which works using a Distributed Coordination Function (DCF)-based technique for interconnecting APs, and also a radio-aware packet forwarding scheme among APs. A major advantage of the system is that, putting routing issues aside, it introduces no changes into the MAC protocol of IEEE 802.11. The simulation results obtained in OPNET v.10.0 show the great potential of our mesh architecture to support real-time traffic with any packet size, and the effectiveness of the radio-aware forwarding scheme in improving the delay performance of the mesh network.