Clear Channel Assessment in Ultra-Wideband Sensor Networks

Bin ZHEN  Huan-Bang LI  Ryuji KOHNO  

IEICE TRANSACTIONS on Communications   Vol.E91-B   No.4   pp.998-1005
Publication Date: 2008/04/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e91-b.4.998
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Network
ultra-wideband,  preamble-assisted modulation,  clear channel assessment,  wireless sensor networks,  

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Impulse ultra-wideband (UWB) is an attractive technology for large ad hoc sensor networks due to its precise ranging capacity, multi-path fading robustness and low radiation power. The transient and carrier-less nature of low radiation pulse and harsh multipath channel condition makes it cumbersome to implement carrier sensing. We proposed clear channel assessment (CCA) based on preamble-assisted modulation (PAM) for UWB sensor networks. Preamble symbols are periodically inserted into the frame payload in the time domain to serve as regular feature for reliable CCA. We simulated the CCA performance in the multipath UWB channel model developed by IEEE 802.15.4a. PAM and CCA configurations were optimized for the distributed carrier sense multiple access protocol. PAM was accepted by 802.15.4a group as an optional feature. Furthermore, the multiplexed preamble symbols can be exploited for channel estimation to improve communication and ranging.