Exact evaluation of capture effect under NCFSK demodulation
Wei Ren, J. Ward, Stephen Hodgart, Martin N. Sweeting · IEE Proceedings - Communications · 2001
The capture effect can improve throughput of random multiple access protocols. An exact model for evaluating the capture effect is proposed for noncoherent FSK demodulation (NCFSK) under a slow fading assumption. This model takes into account the bit decision process of the NCFSK demodulator in the presence of both co-channel interference and noise. An approximate and simplified model is also presented for comparison. Additionally, a Gaussian assumption-based model is derived, which turns out to be too pessimistic for slow fading channels. The capture effect is investigated by means of the proposed exact model in a low Earth orbit satellite channel. The result shows that a relatively large link margin can result in a large capture probability, and consequently benefit slotted ALOHA protocols with a substantial throughput improvement.