Optimization of Non-Orthogonal Multiple Access Based Visible Light Communication Systems

Abstract

In visible light communication (VLC), the data is transmitted by modulating the light emitting diode (LED). The data-rate is throttled by the narrow modulation bandwidth of LEDs, which becomes a barrier for attaining high transmission rates. Non-orthogonal multiple access (NOMA) is a new scheme envisioned to improve the system capacity. In addition to multiple access schemes, optimization techniques are applied to further improve the data rate. In this letter, convex optimization is applied to NOMA-based VLC system for downlink. The proposed optimization system is analyzed in terms of the bit error rate (BER) and the sum-rate.

On the Achievable Max-Min User Rates in Multi-Carrier Centralized NOMA-VLC Networks

“…5a, box-plot type is used to show the results; therefore, for the reader's convenience, it is necessary to briefly describe the main elements of the box-plot: (i) The median of the number of iterations needed for convergence (y-axis values) is shown by the red line in the middle of the boxes, (ii) the ends of the boxes show the lower (Q1) and the upper (Q3) percentile of the y-axis values, (iii) the small horizontal lines above and beneath the boxes, called the whiskers, show the lowest and the highest value of the number of iterations needed for convergence excluding the outlier points, (iv) the outlier points are denoted here in a red plus sign and refer to the unexpected In Fig. 5a, the number of iterations needed for convergence considering a different number of users in the network, [10,20,30,40] users, is demonstrated. One can observe from the figure that for all considered cases, the algorithm successfully prevents the LEDs from having an odd number of users with a relatively low number of iteration.…”

“…In Fig. 5a, the number of iterations needed for convergence considering a different number of users in the network, [10,20,30,40] users, is demonstrated. One can observe from the figure that for all considered cases, the algorithm successfully prevents the LEDs from having an odd number of users with a relatively low number of iteration.…”

“…In the above equations, Equation (20) ensures that the percentage difference between the maximum and minimum data-rates of any two users should be lesser than a predefined constant C ∈ [0, 1]. Equation ( 21) ensures that no user suffers a service outage.…”

Design and Demonstration of a TDD-Based Central-Coordinated Resource-Reserved Multiple Access (CRMA) Scheme for Bidirectional VLC Networking

“…In another study [10], the NOMA scheme was introduced to enhance the achievable throughput in high-rate VLC downlink networks. An optimization formulated as a multiobjective non-convex function using the cuckoo search (CS) algorithm was proposed for an NOMA-based VLC system for downlink transmission in [11]. Research on orthogonal frequency division multiplexing (OFDM) can enhance the utilization of the VLC frequency.…”

Power Allocation Optimization in NOMA-Based Multi-Cell VLC Networks

“…Several works proposed solutions for improving the sumrate in single-cell NOMA-VLC networks. In [6]- [8], power allocation (PA) schemes were proposed, which outperformed the gain ratio PA. Cuckoo Search (CS) optimization was used in [9] to optimize the VLC system parameters, including PA, with the objective of maximizing both the received power and the achievable rate. In [10], a joint power-line communication (PLC)-VLC PA strategy was proposed to maximize the network sum-rate.…”