A Physical Layer Scheme in Two-Way Relay Networks with Soft Network Coding

The previous schemes are introduced, including traditional network coding (NC) scheme, physical-layer network coding (PNC) scheme, soft network coding (SNC) scheme and pseudo physical-layer network coding (PPNC) scheme. As an improved scheme of PNC, PPNC does not need synchronization mechanism, however its BER performance gets worse due to the hard decision applied on the relay node. The new proposed pseudo physical-layer soft network coding (PPSNC) scheme adopts soft decision not hard decision compared with PPNC scheme. The computational complexity and BER performance of the proposed scheme are analyzed and compared with the previous schemes. Theoretical analysis shows that the proposed scheme has similar computational complexity with PPNC scheme, and has lower computational complexity than the other schemes. The simulation results show that the proposed scheme has better BER performance than PPNC scheme. At the same time, the performance of PPSNC in MIMO environment is also discussed. The simulation results show that PPSNC scheme in MIMO environment outperforms the previous schemes.