Date Added: Jul 2011
To maximize lifetime of Wireless Sensor Networks, medium access control protocols usually trade off reliability for energy efficiency. Channel errors, collisions, idle listening, and overhearing further aggravate the problem. The authors' paper investigates opportunities to improve reliability in Wireless Sensor Networks under such constraints. They consider a multi-hop data gathering network in which sensor nodes are deployed around a sink. Nodes periodically sense data and forward it to next hop nodes. For such a network, a Medium Access Control protocol, called CPS-MAC, is proposed. This protocol uses cooperative communication to improve reliability by using overhearing to its advantage. In conventional protocols, overhearing causes nodes to receive packets which are not meant for them.