QoS Specific Medium Access Control for Wireless Sensor Networks with Fading

A new MAC protocol is proposed for the reachback operation in a wireless sensor network deployed for reconstructing a random field. Referred to as QUality-of-service specific Information REtrieval (QUIRE), the proposed protocol optimizes the network performance under the metric of information rate per slot per Joule while ensuring a given QoS requirement. Based on the density of sensor deployment and the QoS requirement specified by the maximum distortion for random field reconstruction, QUIRE partitions the sensor network into disjoint and equal-sized cells. It completely eliminates redundant transmissions by ensuring, via carrier sensing, that only one sensor in each cell transmits. It fully explores the diversity of a fading environment by incorporating channel state information into carrier sensing so that the sensor with the best channel transmits. Simulation results demonstrate that QUIRE achieves orders of magnitude of improvement in system latency and energy expenditure over fixed allocation schemes such as TDMA and random access protocols such as slotted ALOHA.