Uplink Interference Mitigation Techniques for Coexistence of 5G Millimeter Wave Users With Incumbents at 70 and 80 GHz

Abstract

The millimeter wave spectra at 71-76GHz (70GHz) and 81-86GHz (80GHz) have the potential to endow fifth-generation new radio (5G-NR) with mobile connectivity at gigabit rates. However, a pressing issue is the presence of incumbent systems in these bands, which are primarily point-to-point fixed stations (FSs). In this paper, we first identify the key properties of incumbents by parsing databases of existing stations in major cities to devise several modeling guidelines and characterize their deployment geometry and antenna specifications. Second, we develop a detailed uplink interference framework to compute the aggregate interference from outdoor 5G-NR users into FSs. We then present several case studies in dense populated areas, using actual incumbent databases and building layouts. Our simulation results demonstrate promising 5G coexistence at 70GHz and 80GHz as the majority of FSs experience interference well below the noise floor thanks to the propagation losses in these bands and the deployment geometry of the incumbent and 5G systems. For the few FSs that may incur higher interference, we propose several passive interference mitigation techniques such as angular-based exclusion zones and spatial power control. Simulation results show that the techniques can effectively protect FSs, without tangible degradation of the 5G coverage.

A Review on Coexistence Issues of Broadband Millimeter-Wave Communications

“…In particular, there is a growing interest in the coexistence of cellular networks and existing incumbents over the band beyond 70 GHz [126], since this band is licensed worldwide and features a large available spectrum [127]. Over this band, the interference from the interferer to the victim depend on three factors: the path loss, the equivalent isotropic radiated power (EIRP) from the interferer, and the effective antenna gain at the victim [111], [128], [129].…”

“…For the active mitigation, probes installed near the victim monitor the level of interference caused by each of the cells and require the cells generating an excess level of interference offload part of work to other cells [127]. For the passive mitigation, the common approaches adopted include angular exclusion zones [111], [129], [130], which limit the use of beams within some sectors in the angular domain, and power control [129], which adjust the interferer transmit power.…”

Towards green communication in 5G systems: Survey on beamforming concept

“…In [46], an uplink interference computation algorithm was designed for 70 and 80 GHz frequency bands to mitigate the interference by sectoring the cell zones and exclude certain zones from the transmission via switching off certain beams. Moreover, the spatial power control method helps in elevating the coverage area affects resulting from the beam on/off method.…”

Interference Challenges and Management in B5G Network Design: A Comprehensive Review

“…The combined frequency range depends on a direct transmission in order to mitigate the path loss for the cellular users (CUs) in both Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) transmission [23]. However, because of the short wavelength as well as several intra-cell interferences by neighboring devices, the frequency bands of B5G suffer from attenuation, fading, reflection, refraction, scattering, shadowing, and absorption by brick walls and concrete buildings, preventing them from penetrating long distances [24,25]. Meanwhile, in ultra-dense network urban areas, users face penetration, scattering, and interference problems.…”