On the cooperation gain in 5g heterogeneous networking systems

In 5G networking, it is promising to integrate cellular system and wireless local area networks (WLAN) to enhance the throughput. The access point of the WLAN can be authenticated as a relay receiver in cellular system to assist the communication between the base station and the user equipment. In this paper, we model the integrated system as a Receiver Frequency Division Gaussian Relay Channel (RFD-GRC) and study how to improve the achievable transmission rate by adopting Decode-and-Forward (DF) and Compress-and-Forward (CF) schemes in the system.Specifically, making use of the orthogonality between the source frequency band (SFB, the cellular system frequency band) and the relay frequency band (RFB, the WLAN frequency band), we independently divide the available SFB and RFB into two subbands and adopt DF and CF in the two subbands, respectively. Joint bandwidth and power allocation of this hybrid DF-CF scheme is optimized, resulting in a cooperation gain larger than that achieved by DF and CF schemes individually.A sub-optimal setting for the hybrid DF-CF scheme is also given, simplifying the implementation and approaching the optimal rate performance. Numerical analysis confirms the effectiveness of the new scheme.