Interference-Aware NOMA for Cellular-Connected UAVs: Stochastic Geometry Analysis

Abstract

Efficiency of cellular-connected UAVs is challenged by spectrum inefficiency, limited number of concurrent connectivity, and strong interference. To overcome these issues, in this paper, we study the performance of downlink non-orthogonal multiple access for cellular-connected UAVs. We develop a novel framework based on stochastic geometry for the co-existence of aerial users (AUs) and terrestrial users (TUs), where the spatial distribution of the base stations (BSs) follows a Poisson Point Process. In our analysis, two user association policies and two types of receive antennas are considered while an intercell interference coordination (ICIC) technique is also in place. As the main performance measures, we then analytically derive the coverage probability and average rate of AUs and TUs. These derivations are then used to provide quantitative insights on the impact of different system parameters and settings including AU's altitude, TU's distance from the BS, power allocation, successive interference cancellation (SIC) constraints, user association policy, antenna beamwidth, and the number of coordinated BSs. Based on our analysis we then propose an interference-aware scheme based on maximum-SINR user association, directional antenna, and ICIC. A benchmark scheme based on minimum-distance user association, omni-directional antenna, and without ICIC is considered. Compared to the benchmark scheme, our proposed scheme improves the AU's coverage probability by threefold and TU's average rate by sixfold. Compared to the orthogonal multiple access, our proposed scheme trades off a slight reduction in the AU's coverage probability (~1%) with a significant increase in the achieved rate of the TUs (603Kbps/resource block).

A Systematic Review of Interference Mitigation Techniques in Current and Future UAV-Assisted Wireless Networks

“…The authors of [38] study the downlink performance of NOMA for UAV-assisted wireless networks. A new framework based on stochastic geometry is developed for the co-existence of terrestrial users and aerial users where the Poisson point process governs the BSs's spatial distribution.…”

Performance Analysis of Directional Ultra-Dense Networks with Dynamic Spectrum Partition Strategy

“…A distance-based ICIC for edge users in small cell networks was introduced in [25], and then the coverage probability of edge users was derived using stochastic geometry. Te authors of [26] studied the coverage probability and average rate of downlink non-orthogonal multiple access for cellular-connected UAVs with user association ICIC scheme. However, the interference management strategies of cellular networks mentioned in the literature above are all from the level of network framework, without considering how to avoid intercell interference from the perspective of users.…”

“…(1) Initialize: N i,j � 0, C se,j � [0, 2π). ( 2) for i � 1 to N s do (3) Calculate N i,u ; (4) for t � 1 to N i,u do (5) Calculate θ se,t and then obtain the shaded area coverage C sh,t ; (6) for j � 1 to N c do (7) if j ≠ N c then (8) if N i,j � 0 then (9) if φ se,j �� ϕ or φ se,j ∈ [0, 2π)/C sh,t then (10) Subchannel B j is assigned to to u t ; (11) Mark C se,j � C se,j /C sh,t ; (12) Mark N i,j � 1; (13) break; (14) else if φ se,j ∈ C sh,t then (15) Return to line 5; (16) end if (17) else if N i,j � 1 then (18) Return to line 5; (19) end if (20) else (21) Select an idle subchannel B j to assign it for u t ; (22) Mark C se,j � C se,j /C sh,t * ; (23) Mark N i,j � 1; (24) end if (25) end for (26) end for (27) end for * If used, the tag is invalid.…”

Rethinking Dense Cells for Integrated Sensing and Communications: A Stochastic Geometric View

“…The authors in [16] provided analytical frameworks for system-level analysis and design of up-link heterogeneous cellular networks where the locations of multiple antennas BSs modeled as points of homogeneous PPP. In addition, a novel framework based on stochastic geometry for the co-existence of aerial and terrestrial users was developed in [17], where the spatial distribution of the BSs has been assumed to follow a PPP. Tractable framework for symbol error probability, outage probability, ergodic rate, and throughput for downlink cellular networks with different MIMO configurations based on SG approach have been provided in [18].…”