Aspects of favorable propagation in Massive MIMO

By Hien Quoc Ngo, Erik G. Larsson, T. Marzetta. European Signal Processing Conference, 2014

303 citations recorded by the source corpus.

Favorable propagation, defined as mutual orthogonality among the vector-valued channels to the terminals, is one of the key properties of the radio channel that is exploited in Massive MIMO. However, there has been little work that studies this topic in detail. In this paper, we first show that favorable propagation offers the most desirable scenario in terms of maximizing the sum-capacity. One useful proxy for whether propagation is favorable or not is the channel condition number. However, this proxy is not good for the case where the norms of the channel vectors are not equal. For this case, to evaluate how favorable the propagation offered by the channel is, we propose a “distance from favorable propagation” measure, which is the gap between the sum-capacity and the maximum capacity obtained under favorable propagation. Secondly, we examine how favorable the channels can be for two extreme scenarios: i.i.d. Rayleigh fading and uniform random line-of-sight (UR-LoS). Both environments offer (nearly) favorable propagation. Furthermore, to analyze the UR-LoS model, we propose an urns-and-balls model. This model is simple and explains the singular value spread characteristic of the UR-LoS model well.

Subfields: Computer Networks and Communications, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/d8f6d396396494b35b9b94d16886b563b91f73d4

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Citations in the corpus

Channel Hardening and Favorable Propagation in Cell-Free Massive MIMO With Stochastic Geometry (2017, background): “Favorable propagation means that the users’ channel vectors are almost orthogonal [18].”
Wireless Access in Ultra-Reliable Low-Latency Communication (URLLC) (2018, background): “This property is rather speciﬁc to systems operating below 6 GHz in a rich scattering environment [39].”
6G and Beyond: The Future of Wireless Communications Systems (2020, background): “This characteristic is most prominent in classic massive MIMO communications [161].”
Massive MIMO Performance Evaluation Based on Measured Propagation Data (2014, background): “The term “favorable” is first defined in [6] as the mutual orthogonality among user channels, and “favorable” propagation is further investigated in theory in [7].”
Millimeter Wave Communications for Future Mobile Networks (2017, background): “Due to the highly directional transmissions in mmWave communication systems, users from different directions may be well separated using different spatial beams, which is also known as favorable propagation [191].”