An Investigation of Cooperative Slotted ALOHA with the Capture Effect

It has been shown that cooperative transmissions improve the throughput of slotted ALOHA. However, the impact of the capture effect on cooperative slotted ALOHA, which has practical significance for radio channels with fading, shadowing and the near-far effect, remains unknown. This paper proposes and analyzes a random access protocol which incorporates cooperative transmissions and the capture effect in slotted ALOHA. Numerical results illustrate that this scheme improves the throughput by 56% in Rayleigh fading channels when the capture ratio is 3 dB as compared to cooperative slotted ALOHA without the capture effect.