THROUGHPUT–FAIRNESS OPTIMIZATION FOR WI-FI AND LTE-LAA COEXISTENCE IN THE UNLICENSED 5 GHZ SPECTRUM: A PROPORTIONAL FAIRNESS APPROACH
Area:
Department of Computer Science and Engineering
Abstract:
The rapid growth of mobile data traffic has encouraged cellular operators to build Long Term Evolution (LTE) in the 5 GHz unlicensed band utilizing License Assisted Access (LAA) where the success of LAA depends on fair co-existence with incumbent Wi-Fi networks. Due to the different channel-access criteria of LAA's Listen-Before-Talk (LBT) mechanism and Wi-Fi's Distributed Coordination Function (DCF), uncoordinated coexistence may drastically reduce Wi-Fi performance or underutilize the shared spectrum. We provide a proportional-fair analytically tractable optimisation framework for Wi-Fi/LTE-LAA coexistence on a shared 5 GHz channel. For both networks, we develop closed-form throughput equations based on a discrete-time Markov chain model. To find the optimal channel time-sharing factor, we design and solve a proportional fairness objective under Karush-Kuhn-Tucker (KKT) conditions. With Wi-Fi throughput degradation within 5% of solo performance and an inter-network Jain's Fairness Index (JFI) of 0.95-0.98, extensive simulations show that the suggested system may boost the aggregate LAA throughput by up to 78% over existing fairness-based standards. The results show that the proposed coexistence management approach for 5G-Advanced and upcoming 6G unlicensed-spectrum installations is feasible.
