Performance Analysis of MRC Receivers with Adaptive Modulation and Coding in Rayleigh Fading Correlated Channels with Imperfect CSIT

Abstract

This paper addresses the performance analysis of an adaptive wireless link with one antenna transmitter and a multiple antenna maximum-ratio combining (MRC) receiver. Two main assumptions are used in this paper: (1) Rayleigh fading correlated channels (i.e., MRC branch correlation) and (2) imperfect (outdated) channel state information at the transmitter (CSIT) side. The main contribution of this work lies in the derivation of analytic expressions (in terms of a series expansion) of the statistics of correct packet reception conditional on the decisions made by the transmitter based on outdated CSIT. The novelty of this derivation is the joint modelling of spatially correlated branches, imperfect CSIT, and adaptive modulation based on threshold-trigger decision. Contrary to common belief, the results presented here suggest that spatial correlation not always affects the performance of the MRC receiver: at low signal-to-noise ratio (SNR), correlation can improve performance rather than degrading it. In contrast, at high SNR, correlation is found to always degrade performance. At high SNR, correlation tends to worse the degrading effects of imperfect CSIT, particularly when the number of antennas increases. Imperfect CSIT causes errors in the assignment of MCSs, thus reducing throughput performance. These errors become more evident in the high SNR regime, particularly when the values of branch correlation and the number of antennas increase.

A Space-Time Correlation Model for MRC Receivers in Rayleigh Fading Channels

“…The literature of MRC transceivers has focused on the derivation of outage and bit error probability distributions (see [7][8][9][10][11][12][13][14][15][16][17]). The effects of imperfect channel knowledge at the receiver side of MRC systems in Rayleigh fading correlated channels can be found in [7,8].…”

“…The effects of imperfect channel knowledge at the receiver side of MRC systems in Rayleigh fading correlated channels can be found in [7,8]. Imperfect channel state information at the transmitter side with SINR-based resource allocation for correlated MRC receivers in Rayleigh fading channels was presented in our previous work in [9]. The bi-variate distribution of correlated Rayleigh distributions has been presented in [10].…”

“…1 − λ 2 Y m + λ m Z to calculate the distribution of multivariate chi square distribution with correlation. Our previous work in [9] has used the following linear correlation model to calculate the performance of equi-correlated MRC receivers.…”

“…where Z m and G are auxiliary circular zero-mean independent Gaussian random variables and ρ is the correlation coefficient. The work in [9] used a frequency domain approach to obtain the statistics of the SNR of the MRC receiver. The CCDF (complementary cumulative distribution function) of the post-processing SNR was found to be given by:…”

Adaptive Transmission Power Control for Reliable Data Forwarding in Sensor Based Networks

“…In this way, even if part of data packets is lost during the data transmission, some nodes' data can still reach the sink successfully, which improves the data collection success rate. (d) Improve the reliability of data transmission by using data encoding [32]: the mechanism of this method is that if a packet is encoded in a certain way, the receiver node can deduce the missing data based on the received information even if it does not collect all the data so that the reliability of data transmission is improved. For example, the Error Correcting Code (ECC) method is an effective way to guarantee the reliability of end-to-end packets.…”