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Wireless Control Networks with Real-Time Constraints
Published in V. Çağri Güngör, Gerhard P. Hancke, Industrial Wireless Sensor Networks, 2017
Alphan Ulusoy, Ozgur Gurbuz, Ahmet Onat
Multi-path fading can cause significant degradation in the received signal strength over wireless channels, hence the capacity and quality of wireless communication networks are seriously degraded. Diversity techniques try to alleviate the effects of fading by generating and/or combining independently fading copies of the transmitted signal at the receiver [11], and cooperative diversity is one of the recent techniques to provide antenna diversity across cooperating nodes of a wireless network. In cooperative communications, the wireless broadcast advantage is exploited to disseminate the data to the cooperating nodes and via the cooperative transmissions, the receiver is provided with multiple copies of the original signal emanating from geographically separated transmitters (cooperating nodes); thus creating diversity at the receiver. At the receivers of cooperating nodes, Maximal Ratio Combining (MRC) is implemented, so that signals received from different nodes (branches) are combined in such a way that output Signal to Noise Ratio (SNR) is maximum, equal to the sum of SNRs of individual branches. This results in improved SNR at the receiver, higher link reliability, hence reduced number of retransmissions.
Performances of Digital Receivers
Published in Stefan R. Panić, Mihajlo Stefanović, Jelena Anastasov, Petar Spalević, Fading and Interference Mitigation in Wireless Communications, 2013
Stefan R. Panić, Mihajlo Stefanović, Jelena Anastasov, Petar Spalević
Often, this approach is used for determining the average SNR at the output of the receiver when the maximal-ratio combining (MRC) space diversity technique is applied at the reception and no correlation between the channels is assumed. In such a case, as described later, the output SNR is formed as a sum of the individual channel SNRs, xi, as () x=∑i=1Nxi,
4 Design Considerations for Integrated MIMO Radio Transceivers
Published in Krzysztof Iniewski, Wireless Technologies, 2017
Yorgos Palaskas, Ashoke Ravi, Stefano Pellerano, Sumeet Sandhu
The optimal receiver performs maximal ratio combining (MRC) of two antennas [15,16], which maximizes the SNR. Intuitively, maximal ratio combining optimally aligns the channel phases onboth antennas and weights their amplitudes in proportion to the channel amplitudes. The resulting SNR is proportional to the channel power, that is, the sum of the squares of channel amplitudes on all antennas.
Effect of estimation error on dual MRC receiver over Hoyt fading channels
Published in International Journal of Electronics Letters, 2019
Bhargabjyoti Saikia, Rupaban Subadar
Diversity is a simple and efficient method to counter the issue of fading which exploits the random behaviour of the wireless channels. In an ideal scenario, the maximal ratio diversity combining technique performs optimally (Simon & Alouini, 2005). Nevertheless, in practice avoiding correlation in the case of spatial diversity is almost impossible and with correlation, the performance of diversity receivers degrades. Diversity receivers with antenna correlations have been studied in Aalo (1995), Alexandropoulos (2017), Aruna and Sahu (2012), Kamdar and Xu (2015), Sagias and Karagiannidis (2005) and Subadar and Sahu (2009, 2011) for various channels and combining techniques. Hoyt fading channels consider a non-homogeneous environment, hence more fit with the practically obtained data. Maximal ratio combining (MRC) receiver needs to estimate the channel envelope and the phase to optimise its performance. The performance highly depends on the accuracy of the estimation. The performance of diversity receiver has been studied in Aruna (2015), Aruna and Sahu (2014), Badarneh and Almehmadi (2016), Duong, Shin, and Hong (2007), Jeong, Lee, and Yoon (2011), Ma, Schober, and Pasupathy (2005a, 2005b), Radaydeh (2007), Tang, Aloini, and Goldsmith (1999), Yao (2007) and Yao and Jin (2007), considering channel estimation error. In these papers mainly the bit error rate and outage performance have been studied. It has been observed that the performance of diversity receiver has been studied with correlation as well as estimation error separately. But the combined effect of correlation and estimation error is still not known. This fact highly motivated us to know the performance of the receiver in the presence of both of these effects.