Extended-range Wireless Sensor Networks with Enhanced IEEE 802.15.4 CSMA/CA
28 October 2011
An extended range wireless sensor network (WSN) technology is presented in this paper. The proposed technology is based on the cross-layer optimization of the IEEE 802.15.4 standard. In the physical layer, the use of directive and adaptive phased-arrays is proposed for the WSN gateways. Consequently, a neighbor-cooperative CSMA/CA algorithm is proposed to alleviate the hidden terminal problem that is aggravated with the use of directive antennas at the one side of the communication links (asymmetric links). With the proposed technology, a 3-fold increase of the single-hop range is achieved and transmission efficiency of the MAC is improved with minimal impact on the overall throughput, protocol complexity, overhead efficiency, and scalability.