Cooperative sensor networks with misinformed nodes

The communication capacity of Cooperative SEnsor Networks with Mobile Access (C-SENMA) is considered when some sensors may be misinformed with erroneous messages. It is assumed that a global message is first distributed to all the nodes, each node receiving the message correctly with probability 1-β. The nodes cooperate in delivering the global message to the mobile access point. Three system configurations are discussed based on whether a polling channel and/or an energy constraint are present. The first type is C-SENMA with Polling with No Energy constraints (PNE), where the mobile access point has the ability to poll individual sensors. Without energy constraints, each sensor can transmit for an unlimited number of times. The second type is C-SENMA with No Polling with No Energy constraints (NPNE), where adaptive polling is not allowed and sensors have to transmit according to a predetermined schedule. The third type is C-SENMA with No Polling with an Energy constraint (NPE), where each node has a limit on the number of transmissions. The capacities of the three system configurations are analyzed. It is shown that, the capacity for C-SENMA PNE is the same as that when there are no misinformed sensors. For C-SENMA NPNE, with the absence of the polling channel, there is a loss on the achievable rate, proportional to β, the probability that a sensor is misinformed. Results are extended to multiple simultaneous transmissions with the presence of channel fading. The optimal number of simultaneous transmissions is investigated under three different fading situations.