Abstract-We consider the communication from a cooperative sensor network to a mobile access point. We assume that sensors are informed with a global message and some nodes are misinformed with random messages. Nodes transmit to the mobile access point in a pre-scheduled order. We derive an achievable rate for the information retrieval process when d sensors are transmitting at a time. For the Gaussian multiple access channel under the total network power constraint, we show that the maximum achievable rate for the Gaussian multiple access channel is O(log 2 d), obeying the same scaling law as the capacity of an Gaussian multiple-input-single-output channel.

Abstract-The problem of retrieving information by a mobile access point from a sensor network where sensors cooperatively transmit messages using a common codebook is considered. It is assumed that there is a probability that a sensor is misinformed with a wrong message, which complicates the information retrieval process. The access point uses the capacity achieving stay-k scheduler that schedules a sensor to transmit for k consecutive code-letters before switching to a new sensor. The random coding exponent is derived as a function of k, and it is shown that there is an optimal k that gives the largest error exponent. The application of low-definition parity-check (LDPC) codes is considered next. It is shown in simulations that the optimal k of the stay-k scheduler for LDPC codes can be inferred from that for the random coding exponent.Index Terms-Cooperative transmission, error exponent, low-density parity-check (LDPC) codes, sensor networks.

In signal field reconstruction applications of sensor network, the locations where the measurements are retrieved from affect the reconstruction performance. In this paper, we consider the design of medium access control (MAC) protocols in sensor networks with mobile access for the desirable information retrieval pattern to minimize the reconstruction distortion. Taking both performance and implementation complexity into consideration, besides the optimal centralized scheduler, we propose three decentralized MAC protocols, namely, decentralized scheduling through carrier sensing, Aloha scheduling, and adaptive Aloha scheduling. Design parameters for the proposed protocols are optimized. Finally, performance comparison among these protocols is provided via simulations.

We consider the transmission of two independent sources with different priorities over unknown fading channels. One source (protocol information) has a low information rate and a delay constraint. The other source has a high information rate

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