Design of Wireless Fronthaul With mmWave LOS-MIMO and Sample-Level Coding for O-RAN and Beyond 5G Systems

This paper proposes novel designs of line-of-sight multiple-input multiple-output (LOS-MIMO) and a unique sample-level coding scheme for wireless fronthaul (WFH) deployment in Open Radio Access Network (O-RAN) and beyond the fifth-generation (5G) systems. The objective of these designs is to achieve high capacity, robustness, and ultra-reliability in WFH, providing performance comparable to fiber-optic fronthaul solutions. Firstly, by optimizing array configuration parameters, such as array aperture size, antenna separation, and the proposed analog multipath beamforming scheme, LOS-MIMO operating at millimeter-wave (mmWave) bands emerges as a critical enabler for WFH, delivering the required high data rates to support lower-level split options as defined by the 3rd Generation Partnership Project for fronthaul networks. Furthermore, the use of a non-uniform array design effectively enhances the robustness of WFH by addressing the performance degradation caused by spatial aliasing when LOS-MIMO is employed with uniformly spaced linear array at shorter distances. Additionally, the proposed augmented sample-level coding not only seamlessly integrates with the fronthaul design but also provides benefits for ultra-reliable applications carried over the fronthaul. Through extensive simulations at both system and link levels, it is demonstrated that employing high-rank LOS-MIMO at mmWave bands for WFH ensures high capacity, robustness, and reliable performance. Overall, the analysis presented in this paper establishes that WFH can be effectively designed to meet the stringent requirements of fronthaul networks and represents an attractive option for future disaggregated RAN deployments.