Discrete‐input continuous‐output memoryless channel capacity of cooperative hierarchical modulation

Abstract

Hierarchical modulation (HM) is a layered modulation scheme, which is widely employed by the telecommunication industry. The higher flexibility and lower complexity of the HM scheme has its dramatic benefits for wireless communications, hence the achievable performance of cooperation-aided coded HM has drawn substantial research interests. In this study, a triple-layer HM-aided four-node cooperative communication system is proposed, and its discrete-input continuous-output memoryless channel capacity is derived, which is used for finding the optimal position of the relay nodes as well as to design appropriate HM constellations. The authors' simulation results show that if a rate-1/2 'perfect' channel code is assumed, the four-node network becomes capable of conveying a coded HM-64QAM Q2 signal in three time slots at an average signal-to-noise ratio of −0.71 dB.