Alexander Pastukh

Satellite direct-to-cell connectivity can extend 5G Internet of Things (IoT) services into areas without terrestrial coverage by reusing terrestrial mobile-service spectrum. This study examines aggregate interference at a non-terrestrial network (NTN) satellite receiver in selected bands within 694–2690 MHz, where terrestrial duplex arrangements differ between regions. A satellite receiving an uplink may also receive terrestrial downlink emissions from another country using TDD or an overlapping FDD downlink. Six geographical case studies combine satellite motion, population-based terrestrial deployments, and aggregate-interference calculations over a 180 kHz receiver bandwidth. Results are presented as interference-to-noise ratio (I/N) complementary cumulative distribution functions and geographical maps, with nadir and random off-nadir pointing cases. In the evaluated TDD cases, BS contributions dominate the upper part of the aggregate-interference distributions, and elevated interference extends beyond the emitting countries. These findings identify cross-border interference pathways under the assumed deployments, loading, spectral coupling, and antenna patterns. They do not establish that duplex arrangement outweighs deployment density independently of these assumptions. The adopted −6 dB I/N threshold is a screening reference; service availability, link performance, and the effectiveness of mitigation techniques are not evaluated.

Direct-to-cell (D2C) non-terrestrial networks (NTNs) based on 5G technology are emerging as a key complement to terrestrial cellular networks, extending connectivity to underserved and remote areas while enabling integration with existing mobile ecosystems. As these systems begin operating in frequency bands already used by terrestrial International Mobile Telecommunications (IMT) networks, coexistence becomes critical. This paper presents a victim-centric methodology for evaluating D2C interference into terrestrial 5G networks in the 694/698 MHz-2.7 GHz regulatory study range. Seven downlink carrier cases and four uplink carrier cases between 734 and 2620 MHz are evaluated. For a prescribed external interference-to-noise ratio, the external contribution is referenced to receiver thermal noise, while terrestrial intra-network interference remains part of the baseline and interfered signal-to-interference-plus-noise ratio (SINR). The resulting throughput loss is translated into candidate power-flux-density (PFD) and equivalent-power-flux-density (EPFD) protection levels. A reference non-geostationary-satellite-orbit (NGSO) system is used only to motivate the assumed receiver-exposure fractions; the numerical network results are therefore conditional on those exposure assumptions. The same external interference level produces approximately three times greater network throughput loss at base stations than at user equipment, so direction-specific protection levels are required. For downlink protection, the tested 3 dB noise-rise case gives candidate PFD levels from −109.23 to −98.17 dB(W/(m²·MHz)); for opposite-direction cross-border uplink protection, I/N = −6 dB gives candidate EPFD levels from −138.23 to −130.18 dB(W/(m²·MHz)) for non-AAS base stations. The approximately 11 dB offset for AAS cases results from the maximum-gain normalization used in EPFD and should not be interpreted as evidence of greater satellite exposure. These values are tested candidate levels rather than estimates of an exact 5% crossing point.

The 8.025–8.400 GHz band is one of the key X-band downlink ranges for modern Earth observation satellites, enabling high-rate transmission of imagery and sensor data for agriculture, environmental monitoring, greenhouse gas assessment, disaster response and security-related applications. The potential introduction of 5G networks into this band raises serious concerns about harmful interference to Earth observation ground stations cand, consequently, about the continuity and growth of the global Earth observation data chain. This paper investigates the feasibility of sharing this downlink band between Earth observation systems and 5G networks using a Monte Carlo simulation framework. The model includes a low-Earth-orbit Earth observation satellite with dynamically tracking ground stations and dense urban, suburban and rural deployments of 5G base stations and user devices, together with established radio-propagation and clutter models and representative protection objectives for satellite downlinks. The results suggest that, to keep interference at acceptable levels, ground stations would need to be located far from 5G deployments, which is difficult to achieve in practice and could seriously limit the future expansion of Earth observation infrastructure.

The integration of unmanned aerial vehicles (UAVs) into precision agriculture, as envisioned in the agricultural systems, promises significant gains in crop monitoring, yield forecasting, and targeted agro-technical interventions. However, the use of IMT frequency bands for real-time UAV communications introduces new spectrum sharing and compatibility challenges. Unlike terrestrial user equipment, airborne agricultural drones operate always outdoors, above the base-station downtilt, with predominantly line-of-sight (LoS) propagation to multiple cells, drastically altering compatibility conditions and potentially increasing interference to other operators. This paper proposes a Monte Carlo-based simulation framework analysis of interference generated by such UAVs in IMT frequency allocations across 694–2690 MHz. Simulations model rural and urban macrocell deployments typical of large-scale farmlands, incorporating 3D antenna patterns, altitude-dependent air-to-ground channel models, realistic LTE/NR power-control schemes, and UAV operational patterns. Key metrics include aggregate uplink interference at victim cells, downlink degradation at UAVs, and cross-link interference in TDD systems. Results show that even low-power UAV transmissions can exceed harmful interference thresholds in multiple adjacent-channel cells. Operational recommendations are provided to ensure coexistence of precision-agriculture UAVs with terrestrial IMT networks.

The global expansion of 5G and the anticipated rollout of 6G networks have intensified the demand for mid-band spectrum, particularly within the 4400–4800 MHz range. While the 4800–4990 MHz segment is already standardized for International Mobile Telecommunications (IMT), the 4400–4800 MHz sub-band remains under consideration by the ITU-R due to coexistence concerns with Fixed-Satellite Service (FSS) systems, especially those governed by Appendix 30B of the Radio Regulations. This study investigates the potential interference from 5G/NR base stations to FSS earth stations operating within 4500–4800 MHz using Monte Carlo simulation. Employing realistic deployment parameters and propagation models, the study evaluates long- and short-term interference across varying elevation angles and urban/suburban environments. The results indicate that while significant separation distances are required at very low elevation angles, the risk of harmful cross-border interference is minimal at typical operational angles. These findings support the feasibility of shared use of the 4400–4800 MHz band for 5G/NR without compromising FSS integrity.

This article addresses interference mitigation strategies for radio astronomy service (RAS) within the 6650-6675.2 MHz frequency band, focusing on the 5G NR network deployment and its potential impact on RAS operations. Guided by ITU-R recommendations and methodologies, the study explores both generic and site-specific interference cases. Using Monte-Carlo simulations and propagation models, including Recommendations ITU-R P.2001 and ITU-R P.2108, it estimates interference levels from 5G NR base stations, highlighting necessary separation distances across various deployment scenarios. The results indicate that urban IMT deployment requires a minimum separation of 55-60 km, while rural and suburban setups may necessitate 30-70 km based on terrain shielding and adjacent channel conditions. This study is useful for regulators and network planners that plane to implement 5G NR networks in the countries where the frequency band 6650-6675.2 MHz is in use by RAS, providing adaptable separation guidelines according to local environments and 5G NR deployment specifics.

RedCap technology is set to become a critical component in the growth of the Internet of Things (IoT), enabling sensors and wearable devices for medical, industrial, and commercial applications. However, because RedCap primarily operates in non-public networks and does not synchronize its time-division duplexing (TDD) mode with 5G NR networks, interference risks arise. This is particularly concerning as traditional 5G NR networks prioritize downlink communication, whereas RedCap is designed for uplink. This study investigates the potential interference between RedCap non-public networks and 5G NR in TDD FR1 and FR2 frequency bands using Monte Carlo simulation techniques. The results illustrate how RedCap deployments may impact 5G NR performance in urban and suburban environments. Key insights are provided to inform strategies for minimizing interference and ensuring coexistence between these technologies.

This paper studies the density of active devices in the European Union, China, India, United States and Canada estimating the interference the satellite will experience in the 868 MHz and 915 MHz frequency bands. The analysis evaluates aggregate interference to the satellite IoT uplink (Earth-to-space) using the interference-to-noise ratio (INR) protection criteria. The methodology of calculations is based on the recommendations and reports from the International Telecommunication Union (ITU-R) and widely accepted approaches used in compatibility studies between terrestrial and satellite systems.

This paper presents studies of the effect of the Doppler frequency shift on the satellite link availability when regular smartphones are used as user equipment. The studies evaluated the NTN downlink channel showing how the availability of the link changes when using Doppler shift compensator at the satellite side and when it's not used. Additionally, the study simulates a typical NTN constellation in S-band and compares the link availability time when the Doppler shift compensator is used and is not. Conclusions are drawn about the challenges of using unmodified mobile phones for communication and how it might be affected by the Doppler shift.

The study evaluates the possibility of the shared use of the 6425-7125 MHz frequency band between licensed and unlicensed systems namely by 5G and Wi-Fi technologies respectively. Using Monte-Carlo analysis, the study simulates work of the 5G network in the presence of Wi-Fi devices with different density rates. The results of the study are presented as 5G downlink and uplink throughput losses due to the interference from Wi-Fi devices. Based on the results, it is shown that hybrid sharing of the upper 6 GHz band is not feasible and should be avoided.