Interference Suppression Performance of CMA Using Time-Domain Inter-Symbol Spreading in Time-Varying Channel Environment

Blind adaptive array (BAA) can suppress unknown co-channel interference without reference signal. Vehicle-to-everything (V2X) communication and underwater acoustic communication (UWAC) are seen as promising application towards Beyond 5G and 6G. Capacity enhancement is still essential for such extensive scenario and thus effective interference suppression can contribute to realizing efficient spatially multiplexed transmission without frequent reference signal insertion. Focusing on the constant modulus algorithm (CMA) as one of the BAAs, this paper investigates its fundamental interference suppression performance under the intense time varying channel environment, anticipating UWAC application. In addition, effectiveness of time-domain inter-symbol spreading (TISS) to expand operating domain of CMA is also clarified under several interference environment.