Dynamic Constellation Mapping and SER Performance for Asynchronized PNC Using QPSK
Aditi Singh, Tamseel Mahmood Syed, L.L. Joiner · 2020 10th Annual Computing and Communication Workshop and Conference (CCWC) · 2020
The increased throughput performance of physical-layer network coding (PNC) has led to rigorous research in this field for two-way relay systems or multi-way systems. For coherent detection of information received by the relay node and decoding the correct symbols transmitted by the user nodes after removing self-information, synchronization in the system is a critical requirement. This paper aims to study the symbol error rate (SER) performance of an asynchronized PNC system, i.e. a system with phase misalignments. The symbols of two end users arrive with a phase difference of φ. We study a mapping scheme for the combined signal at the relay based on its superimposed constellation structure incorporating the phase difference φ. An analytical bound on SER performance at the relay node in presence of phase difference φ is derived. Simulation results showing identical SER performance for a fixed value of φ, independent of the individual link phase offsets, have been presented. It can be seen that mapping provides better spectral efficiency when compared to the de-noise and forward scheme with a slight tradeoff in SER performance compared to non-mapped case.