Energy Efficient Clear Channel Assessment for LR-WPAN
IEEE 802.15.4 LR-WPAN is a specification for low-cost, low-powered and low data rate transmission. This standard uses CSMA/CA protocol for contention resolution. One of the tasks performed by CSMA/CA algorithm is Clear Channel Assessment (CCA), used to find the status (IDLE or BUSY) of the channel. There are three operating modes to perform CCA. As per the standard CCA mode 2 and 3 are based on carrier sensing where as CCA mode 1 is based on Energy Detection Threshold (EDThreshold). CCA in most of the WPAN is based on carrier sense. EDThreshold dependent CCA mode 1 is more advantageous in case of energy constraint networks, as minimum energy is consumed in channel allocation using EDThreshold. This property of EDThreshold is utilized in CCA for LR- WPAN and is implemented in NS2. Simulation results of EDThreshold based mode 1 CCA indicate that number of packets dropped decreases, network as well as node throughput increases and energy consumption is also less when compared to Carrier Sense Threshold (CSThreshold) based mode 1 CCA, It is also observed from the results that MAC_PACKET_ERROR is also acceptable (i.e < 1% ).
Keywords: CCA, Carrier sensing, EDThreshold, LR-WPAN
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