Performance Analysis of Physical Layer Network Coding for Two-Way Relaying over Non-Regenerative Communication Satellites

Two-way relaying is one of the major applications of broadband communication satellites, for which Physical Layer Network Coding (PLNC) is an efficient technique. Earlier studies have considered satellites employing PLNC with onboard processing. This paper investigates the performance of PLNC over non-regenerative satellites, as a majority of the operational and planned satellites do not have onboard processing. Assuming that the channel magnitudes of the two users are equal, two operating conditions are considered with uncoded-QPSK relaying. In the first operating condition, both users are completely synchronized in phase and transmit power, and in the second operating condition, phase is not synchronized. The peak power constraint imposed by the satellite amplifier is considered and the error performance bounds are derived for both the conditions. The simulation results for end-to-end Bit Error Rate (BER) and throughput are provided. These results shall enable communication system designers to decide system parameters like power and linearity, and perform trade-off analysis between different relaying schemes.