Channel Estimation and Carrier Offset Control for Cooperative MIMO Sensor Networks

A sensor network is considered with a multiple antenna element collector node and single element sensor nodes. The sensors form a cooperative MIMO network employing eigencoding on the uplink with variable-rate transmission. The individual sensors have differing frequency offsets which must be estimated at the collector along with the flat-fading channel and propagation delays. Offset and timing control commands are transmitted on the downlink with the eigencode and water-filling powers. A generalized successive interference cancellation (GSIC) algorithm for collector-based channel/offset/delay estimation is presented with quadratic complexity in the number of sensors. Analytical and simulation results demonstrating the efficacy of GSIC and performance degradation due to carrier offset/channel/timing estimation errors are given