Penalised and doubly-penalised parallel/successive interference cancellation multi-user detectors for asynchronous upstream optical code division multiple access passive optical network

Optical code division multiple access (OCDMA) is one of the emerging technologies for next generation passive optical networks that can offer customers a Gb/s-class experience in the upstream. However, OCDMA suffers from multiple access interference (MAI) that significantly reduces the capacity of the system. To mitigate MAI, three novel interference cancellation (IC) techniques have been proposed for incoherent direct sequence OCDMA systems that make use of some prior information to enhance their performance. Some of the IC structures exploit the non-negativity of the solution, while others exploit in addition to the non-negativity information the noise variance information. The proposed IC detectors outperform the conventional correlation receiver, the decorrelator detector, the linear parallel/successive interference cancellation detectors and even the linear minimum mean square error detector.