High Connectivity with Minimum BER in Wireless Sensor Networks

Power saving is considered a significant issue relating to wireless ad hoc and sensor networks, where nodes normally use limited battery power. Transmitting using unnecessary high power introduces excessive interference. It is much better if the network designer would have each node transmit at the lowest possible power while the network connectivity is preserved. This paper introduces the optimal common transmit power, defined as the minimum transmit power used by all nodes necessary to guarantee network connectivity. This is desirable in sensor networks since nodes are relatively simple, while modifying transmit power after deployment is difficult. The optimal transmit power used in this paper has been derived in previous work. It is subject to the specific routing and medium access control (MAC) protocols considered. However, the approach can be additionally extended to other routing and MAC protocols. In this paper, connectivity is defined in terms of a quality of service (QoS) constraint given by the maximum tolerable bit error rate (BER) at the end of a multihop route with an average number of hops. General Terms Sensor networks, Ad hoc wireless networks, power saving, network connectivity. Keywords medium access control (MAC), quality of service (QoS), bit error rate (BER), probability mass function (pmf). 1