A Real-Time Asynchronous Uplink UOWC System Based on Multiuser Detection Technique

In this paper, a real-time asynchronous code-division multiple access (CDMA) based uplink multiuser system for underwater optical wireless communication (UOWC) is proposed and implemented. A parallel receiver structure is introduced to balance the algorithm complexity with real-time performance. The proposed system mitigates the impact of multiuser sampling frequency offsets and multiple access interference (MAI) through a delay update scheme and a multi-branch decorrelating detector. The real-time performance for three users is evaluated under dynamic bubble channel. Experimental results demonstrate the system's effectiveness in mitigating the dynamic channel effect and MAI, as well as the system's support for real-time asynchronous access.