Enhanced CCA Scheme for Slotted CSMA/CA in IEEE 802.15.4 LR-WPANs

Saeyoung AHN  Wook KIM  Sunshin AN  

IEICE TRANSACTIONS on Communications   Vol.E94-B   No.4   pp.1072-1075
Publication Date: 2011/04/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.1072
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Network
CSMA/CA,  CCA,  frame acknowledgement,  beacon-enabled mode,  energy efficiency,  802.15.4,  LR-WPAN,  CC2420,  

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Recently, IEEE 802.15.4 has been standardized for WSNs (Wireless Sensor Networks). This paper proposes an enhanced CCA scheme which involves the data transmission device sending a notifyBusyChannel (nBC) signal in the backoff period when the Channel Using Quotient (CUQ) exceeds 0.5. The CUQ stands for the rate of channel utilization in the previous slot duration. In a single CCA operation, the device nodes are made aware of the busy status of the channel by the nBC signal. We implement the ECCA scheme in a hardware chip for a performance evaluation. The results show that the proposed scheme has short queuing times and less energy consumption than IEEE 802.15.4 CCA. And the scheme is compatible with conventional IEEE 802.15.4 devices.