Joint serially concatenated continuous phase modulation and physical-layer network coding

This paper presents a joint physical-layer network coding (PNC) and serially concatenated continuous phase modulation (SCCPM) scheme in a two-way relay (TWR) channel. This proposed scheme can be viewed as a serial concatenated codes (SCCs) scheme in which the joint CPM and PNC is the inner code and the convolutional code (CC) is the outer code. It aims to improve the spectral efficiency, error performance and power efficiency of the PNC system by utilizing the technical advantage of CPM and SCCs. An iterative decoding algorithm for the relay receiver over AWGN channels is investigated. Emphasis is put on the extrinsic logarithmic likelihood ratios (LLRs) of the XORed codewords generated by the soft input soft output (SISO) inner decoder. Simulation results are also provided to show the error performance of the joint scheme.