BAN-BAN Interference Rejection With Multiple Antennas at the Receiver

Rejection of interference from a nearby body area network (BAN) becomes significant in BAN applications, where a number of BANs are operating in the near vicinity of each other. Two interference rejection combining (IRC) techniques, optimum combining (OC) and Weiner-Hopf (WH) solution, are applied to the on-body wireless communication channels, and a more robust interference rejection technique, applicable to on-body channels, is proposed and compared to the conventional IRC algorithms. Three on-body channels are investigated by real time measurements of the desired and interference signals in an indoor environment with the antennas mounted on two human subjects walking around each other. The output signal to interference plus noise ratio improvement achieved with each algorithm is presented for the three channels and the dependence of the interference rejection gain on the average desired signal to interference ratio has been shown along with the covariance matrices for each channel. OC gives around 3-5 dB interference rejection gain for belt-wrist and belt-head channels. The WH solution gives the worst performance for all the channels. The proposed algorithm gives a flexible handle on the interference rejection gain and gives better rejection than the two conventional algorithms with proper interval selection.