Relative performance of BPSK & BFSK in underground mine communication considering multi path and bending losses

Abstract

Wireless/Mobile signals get strongly attenuated deep inside a building/tunnel/mine. In order to study the performance parameters, underground communication channel needs to be modeled. As a first step here we have practically tried two digital modulation methods BPSK and BFSK for underground communication. Wireless link was able to support data signals. Various measurements were made up to a depth of 30 m inside the mine.  Beyond 30 m as more than 75% of the received signal was attenuated measurements was not possible.  Received signal strength, power line noise effects are measured. SNR, E_b/N_o, P_e (Probability error), penetration loss multi path, and bending loss are calculated up to 30 m depth. Using these results channel modeling can be done. For the measured data we are trying to fit empirical equations.

Keywords: Mine communication, BPSK, BFSK