A performance model for maximum ratio combining receivers with adaptive modulation and coding in Rice fading correlated channels

This paper presents a packet reception model of a wireless link with a single-antenna transmitter and a multiple-antenna maximum-ratio combining (MRC) receiver. The objective of this model is to assist in the performance evaluation of systems with adaptive modulation and coding (AMC) in Rice fading channels under the effects of channel or branch correlation. The model is useful for cross-layer design purposes, as it provides an accurate and relatively low-complex representation of the underlying physical (PHY) layer. This means that the model can be included in the optimization of upper layers without requiring a full PHY-layer simulation or model. The paper focuses on the derivation of closed-form expressions of correct packet reception probabilities of different modulation and coding schemes (MCSs) with different values of block error rate (BLER) and spectral efficiency. The results indicate that channel correlation is not always a source of reduction of link-layer throughput of a multiple antenna system. At low values of signal-to-noise ratio (SNR), channel correlation can improve performance rather than reducing it. By contrast, at high SNR values, channel correlation is shown to always reduce the performance of the receiver. It is also observed that high values of Rice factor tend to reduce the influence of the random signal component and thus the degrading effect of correlation. The line-of-sight component tends to reduce performance in high SNR scenarios, but considerably improving it in the low SNR regime.