Differential amplify-and-forward relaying using linear combining in time-varying channels

Differential encoding and decoding can be employed to circumvent channel estimation in wireless relay networks. This article studies differential amplify-and-forward relaying using linear combining with arbitrary fixed combining weights in timevarying channels. An exact bit error rate (BER) analysis is obtained for this system using DBPSK modulation and over time-varying Rayleigh fading channels. The analysis is verified with simulation results for several sets of combining weights and in various fading scenarios.