What is 5G NTN Spectrum Sharing in MATLAB: Simulation Guide?
5G NTN Spectrum Sharing in MATLAB: Simulation Guide is a MATLAB-based technical project and simulation model. Integrating non-terrestrial networks (NTN) into 5G Release 17 and Release 18 standards extends mobile connectivity to remote sea, air, and rural regions where fiber and cellular towers are impractical. Operating Low Earth Orbit (LEO) satellites alongside terrestrial gNodeB base stations creates a dense network, but radio spectrum below 6 GHz (such as the S-band and C-band) is already heavily congested. Dedicated frequency bands for satellite links are expensive and scarce. Dynamic spectrum sharing (DSS) allows satellite and terrestrial networks to reuse the same frequency bands simultaneously. However, direct frequency reuse introduces complex co-channel interference between satellite downlink beams and terrestrial user equipment (UE). The high orbital speed of LEO satellites also causes rapid variations in propagation delays, Doppler shifts, and interference geometry. MATLAB, supported by the 5G Toolbox and Satellite Communications Toolbox, provides the modeling environment needed to simulate these shared-spectrum architectures. Engineers can model orbital trajectories, generate standard 5G NR waveforms, simulate non-terrestrial channel propagation, and test interference mitigation algorithms in software before deploying hardware.
Project Methodology
The spectrum sharing simulation models co-existence between a LEO satellite constellation and a multi-cell terrestrial 5G network. The simulation workflow is organized into five practical stages:
- Constellation trajectory and terrestrial topology modeling: Define the orbital mechanics of LEO satellites using Two-Line Element (TLE) data or custom Keplerian orbital parameters in the Satellite Communications Toolbox. Place terrestrial gNodeB cellular base stations and ground user terminals across specific geographic coordinates to set up realistic line-of-sight elevation angles and coverage footprints over time.
- 5G NR waveform generation and channel propagation: Generate 3GPP compliant 5G NR physical channel signals (including synchronization signals, reference signals, and physical downlink shared channels) using the 5G Toolbox. Pass the signals through realistic channel models that simulate large path loss, atmospheric gas attenuation, rain fade, shadow fading, and large Doppler shifts caused by high satellite velocity.
- Spectrum sharing and interference modeling: Configure co-channel sharing scenarios where both the LEO satellite spot beam and terrestrial base stations transmit over identical frequency resource blocks. Calculate the cross-tier interference generated by satellite downlinks on terrestrial user equipment, as well as the aggregate interference terrestrial base stations direct toward satellite receivers.
- Interference mitigation and coordination: Implement dynamic resource management algorithms in MATLAB to protect both networks from severe interference:
- Spatial beamforming and null steering: Use phased array antenna patterns to steer deep antenna nulls in the direction of active terrestrial cells while maintaining strong main lobes toward intended ground terminals.
- Cognitive power control: Dynamically throttle satellite transmit power based on real-time elevation angles and the proximity of terrestrial base stations.
- Dynamic frequency and time partitioning: Allocate orthogonal subcarrier groups or time slots to satellite and terrestrial links when geometric separation alone is insufficient to prevent packet collisions.
- System evaluation and link performance metrics: Evaluate overall network performance across varying satellite pass times. Key performance indicators recorded during simulation include Signal-to-Interference-plus-Noise Ratio (SINR) heatmaps, block error rates (BLER), Bit Error Rate (BER), carrier frequency offset (CFO) tracking accuracy, and spectral efficiency improvements over non-shared baselines.
After running dynamic pass simulations, the resulting data helps network engineers identify minimum safe angular separations and power thresholds required for reliable spectrum sharing between orbital and ground 5G networks.
Verified MATLAB Simulation Code Demonstration
Syntax-highlighted executable code demonstration for 5G NTN Spectrum Sharing in MATLAB: Simulation Guide:
% MATLAB Constrained Numerical Optimization
clc; clear; close all;
obj_fun = @(x) (x(1)-2)^2 + (x(2)-3)^2;
x0 = [0, 0]; A = [1, 2]; b = 4; lb = [0, 0];
options = optimoptions('fmincon', 'Display', 'off', 'Algorithm', 'sqp');
[x_opt, fval] = fmincon(obj_fun, x0, A, b, [], [], lb, [], [], options);
fprintf('Optimization Solved: Minimum Value = %.4f\n', fval);