Layered Adaptive Collaborative Constellation for MIMO Visible Light Communication

In this paper, we propose a novel technique to effectively design a channel adaptive collaborative constellation called the layered adaptive collaborative constellation (LACC) for multiple-input multiple-output visible light communications. Recently, a channel-adaptive space-collaborative constellation (CASCC) that designs the constellation with the consideration of channel into the model to improve the receiver mobility and enhance the error performance. However, this scheme only considers into optimization four constellation points that form a diamond shape in the receiver space. Our proposed scheme effectively exploits the layered structure of collaborative constellation and overcomes the aforementioned drawbacks of CASCC. Furthermore, an improved low-complexity maximum likelihood (ML)-based detector is derived. Simulation results show that the LACC can achieve some performance gain, compared with previous constellation design schemes for different scenarios, especially really high-correlation channels and under imperfect channel state information. Moreover, the proposed detector drastically reduces computational complexity while maintaining the same performance as a traditional ML detector.