Scalar Quantize-and-Forward for Symmetric Half-duplex Two-Way Relay Channels

Scalar Quantize & Forward (QF) schemes are studied for the Two-Way Relay Channel. Different QF approaches are compared in terms of rates as well as relay and decoder complexity. A coding scheme not requiring Slepian-Wolf coding at the relay is proposed and properties of the corresponding sum-rate optimization problem are presented. A numerical scheme similar to the Blahut-Arimoto algorithm is derived that guides optimized quantizer design. The results are supported by simulations.