Resource allocation and interference management in OFDMA-based VLC networks

Abstract

Resource allocation and interference management are two main issues that need to be carefully addressed in visible light communication (VLC) systems. In this paper, we propose a resource allocation scheme that can also handle the intercell interference in a multi-user VLC system that employs orthogonal frequency division multiple access (OFDMA). Particularly, we suggest dividing the cell coverage into two non-overlapping zones and performing a two-step resource allocation process, in which each step corresponds to a different level of allocating resources, i.e., zone and user levels. We initially define both zones in terms of the physical area and the amount of allocated resources and we investigate the impact of illumination requirements on defining both zones. Through simulations, we evaluate the performance of the proposed scheme in terms of the area spectral efficiency and the fairness level between the two zones. We show that both performance measures can be potentially enhanced by carefully setting a certain design parameter that reflects the priority level of the users located in the region around the cell center, denoted as Zone 0, in terms of the achievable rate. We further eventuate the system performance in a realistic transmission ✩ scenario using a simulation tool.Recently, the noticeable advances in white light emitting diodes (LEDs) technology motivated utilizing the visible light spectrum for data transmission along with the white LEDs main function of illumination [6,7,8,9,10,11].In addition to providing the required bandwidth, using white LEDs for data transmission has many advantages over the RF technology. For example, they are cheap, energy efficient and no extra infrastructure is needed since white LEDs would be already installed for lighting. Furthermore, using white LEDs for data transmission would inherently ensure data security since light does not propagate through walls.

Elite User Clustering-Based Indoor Heterogeneous VLC Interference Management and Sub-Channel Allocation Strategy

“…As depicted in Fig. 3, the visible light communication networks are typical ultra-dense networks (UDNs) that have three characteristics: high terminal density, high traffic density requirement and high access point density [15]. The coverage of the VLC AP can be determined by the distance between the half power angle and the vertical ground of the AP.…”

“…Users access the VLC network according to the signal strength strategy (SSS) [11]. When the user is located in the overlapping area of the coverage cell, the user may receive resources distributed by cells more than one [13], [15]. Fig.…”

“…In order to evaluate the performance of the receiver, the degree of satisfaction of the k-th user [15] is used to measure the user's quality of service (QoS) as follows:…”

“…To provide the center user the highest signalto-noise ratio (SNR) with subcarriers resources allocation, authors of Ref. [15] investigate a two-step resource allocation algorithm in which each step corresponds to a different level of the resource allocation process. In Ref.…”

Space Division Multiple Access With Distributed User Grouping for Multi-User MIMO-VLC Systems

“…Nevertheless, since COTS white LEDs usually have a very limited dynamic range and suffer from severe LED nonlinearity, the practical implementation of precoding might be quite challenging [27]. As a multiple access scheme generated from OFDM, orthogonal frequency division multiple access (OFDMA) has already been applied in multiuser VLC systems [28], [29], where the overall modulation bandwidth of the system is divided and shared by all the users. However, the available bandwidth of each individual user becomes relatively small due to spectrum partitioning, which inevitably leads to reduced achievable rate, especially when the VLC system is expected to support a large number of users.…”