Multiplexing Gain of Millimeter-Wave Massive MIMO Systems with Distributed Antenna Arrays

Abstract

This paper is concerned with spatial multiplexing analysis for millimeter-wave (mmWave) massive MIMO systems. For a single-user mmWave system employing distributed antenna subarray architecture in which the transmitter and receiver consist of Kt and Kr subarrays, respectively, an asymptotic multiplexing gain formula is firstly derived when the numbers of antennas at subarrays go to infinity. Specifically, assuming that all subchannels have the same average number of propagation pathsL, the formula implies that by employing such a distributed antenna-subarray architecture, an exact average maximum multiplexing gain of KrKtL can be achieved. This result means that compared to the co-located antenna architecture, using the distributed antenna-subarray architecture can statistically scale up the maximum multiplexing gain proportionally to KrKt. In order to further reveal the relation between diversity gain and multiplexing gain, a simple characterization of the diversity-multiplexing tradeoff is also given. The multiplexing gain analysis is then extended to the multiuser scenario as well as the conventional partially-connected RF structure in the literature. Moreover, simulation results obtained with the hybrid analog/digital processing corroborate the analysis results.

Milimeter-Wave Massive Mimo: A Promising Technology for New and Emerging Networks

“…Here are some of its peculiar advantages: i. Large Bandwidth: mmWave frequencies provide access to large bandwidths, enabling high data rates and increased capacity [19,[21][22][23]. The availability of abundant spectrum allows for the allocation of wider channels, which is particularly beneficial for Massive MIMO systems.…”

“…ii. Spatial Multiplexing: The use of mmWave frequencies enhances spatial multiplexing capabilities, as the smaller wavelengths enable closely spaced antenna arrays [20,23]. This results in higher spatial resolution, allowing for increased capacity and better performance.…”

“…A mmWave massive MIMO system utilizing a distributed antenna architecture can achieve significantly higher multiplexing gain compared to a system with a co-located antenna architecture [23,24]. iii.…”

“…As a result of spectrum scarcity, frequency planning significantly improve the utilization of the available spectrum [43]. However, reusing frequency in neighboring cells creates interferences among users [32,23]. Some key spectrum management techniques in mmWave massive MIMO are: i. Spatial Frequency Reuse (SFR): SFR is a frequency reuse technique that exploits the spatial dimension by dividing the coverage area into multiple sectors or zones.…”