Bandwidth Expansion in a Simple Gaussian Sensor Network Using Feedback

The problem of lossy source channel communication under a received power constraint in a simple Gaussian sensor network is studied in this paper. A group of sensors are placed to observe a common Gaussian source. The noisy observations are then transmitted over a Gaussian multiple access channel (MAC) to the sink, where the source is estimated with a quadratic distortion criterion using all received sensor observations. We propose an analogue transmission scheme that uses noiseless causal feedback from the sink to remove correlation between the observation samples, combined with time division multiple access of the MAC. The proposed scheme offers same performance with reduced received power and sensor network size, compared with optimal transmission scheme with single channel use; and converges to the absolute performance bound with low received power level for the same use of bandwidth.