Abstract
In this thesis, we propose the power allocation schemes for distributed detection in wireless sensor networks and consider the amplifier gain based on the log-likelihood ratio (LLR) of the instantaneous observation signal received by the sensor node. If the absolute value of LLR is large, the instantaneous observation signal could be more reliable and the transmission power should be large. On the other hand, if the absolute value of LLR is too small, the instantaneous observation signal node could be less reliable and the transmission power should be small. But, if the absolute value of LLR is extremely small, we consider the sensor node should not transmit data to the fusion center so as to save power. Therefore, the idea of “censoring” is included in the proposed power allocation schemes. We also propose the power allocation scheme for the sensor nodes with the constrained transmission power since the transmission power of the senor node can not transmit with unlimited power. In addition, we consider the power allocation scheme with fusion weighting according to the different channel noise variances and expect the less total transmission power. Finally, the transmission power of the proposed schemes is compared to the equal power allocation scheme and find that the less total transmission power is required for achieving the same detection error probability.