Shifted Coded Slotted ALOHA

The random access scheme is a fundamental scenario in which users transmit through a shared channel and cannot coordinate each other. In recent years, successive interference cancellation (SIC) was introduced into the random access scheme. It is possible to decode transmitted packets using collided packets by the SIC. The coded slotted ALOHA (CSA) is a random access scheme using the SIC. The CSA encodes each packet using a local code prior to transmission. It is known that the CSA achieves excellent throughput. On the other hand, it is reported that in the coding theory time shift improves the decoding performance for packet-oriented erasure correcting codes. In this paper, we propose a random access scheme which applies the time shift to the CSA in order to achieve better throughput. Numerical examples show that our proposed random access scheme achieves better throughput and packet loss rate than the CSA.