An enhanced multiple random access scheme for satellite communications

In this paper, we introduce Multi-Slots Coded ALOHA (MuSCA) as a multiple random access method for satellite communications. This scheme can be considered as a generalization of the Contention Resolution Diversity Slotted Aloha (CRDSA) mechanism. Instead of transmitting replicas, this system replaces them by several parts of a single word of an error correcting code. It is also different from Coded Slotted ALOHA (CSA) because collided data are used in the iterative decoding of the frame. In MuSCA, the entity in charge of the decoding mechanism collects all bursts of the same user (including the interfered slots) before decoding and implements a successive interference cancellation process to remove successfully decoded signals. Simulations show that the achievable total normalized throughput is greater than 1.25 and 1.4 for a frame of 100 and 500 slots, resulting in a gain of 85% and 75% with respect to CRDSA and CSA respectively. This gain comes from the combination between diversity introduced by the random distribution of the data on the frames and MuSCA decoding algorithm, allows the system to transmit on average more than one packet per slot. This paper is a first analysis of the proposed scheme and opens several perspectives.