A Study of Irregular Repetition Slotted ALOHA Over LEO Satellite Channel with Capture Effect

Abstract

It has been shown that packet repetition and successive interference cancellation (SIC) can effectively improve the throughput of frame-slotted ALOHA (FSA) and have been investigated within the Digital Video Broadcasting (DVB) standardization. However, basing on collision channel model, the throughput upper bound for different versions of FSA is up to 1 packet/slot. Capture effect, which is significant in practical radio channels utilizing power unbalance, can be considered to solve packet colliding problem under high traffic load situation. This paper proposes and analyses irregular repetition slotted ALOHA (IRSA) over low earth orbit (LEO) satellite channel by considering capture effect. The possibility of using link budget to enlarge power differential at satellite receiver is analyzed and a novel scheme of SIC is also provided. Numerical results exhibit that under 3 dB capture threshold, the novel SIC scheme has a 22% improvement in throughput by taking advantages of additional power unbalance.