Performance analysis of gain ratio power allocation strategies for non-orthogonal multiple access in indoor visible light communication networks

Abstract

Non-orthogonal multiple access (NOMA) is a promising method for enhancing the throughput in visible light communication (VLC) networks. In NOMA, signal power domain control, called gain ratio power allocation (GRPA), can significantly improve the user sum rate with full-time frequency resource utilization. In indoor NOMA-VLC networks, the scenario in which users are covered by VLC illuminants on the ceiling is typical. First, this paper proposes a novel GRPA strategy for a single VLC cell. Second, due to the difficulty of direct comparisons between our and previously reported GRPA strategies, this paper presents an alternative lower bound for comparability. Third, in two-and threeuser cases, this paper analytically demonstrates that our NOMA-VLC GRPA strategy outperforms the aforementioned strategy, when successive interference cancellation (SIC) is used. Moreover, in the multi-user case, experimental results show that the average user data rate (AUDR) of multi-user cases under our strategy is better than that under the previous strategy. Finally, our paper provides both analytic and numerical results to prove that VLC single-cell system throughput under our strategy is better than that under the previous strategy. The proposed alternative lower bound is also proved to fit the original NOMA-VLC GRPA target asymptotically based on indoor VLC channels. Furthermore, to achieve the same AUDR, our strategy supports worse received conditions than does the previous strategy.

Strategy-Based Gain Ratio Power Allocation in Non-Orthogonal Multiple Access for Indoor Visible Light Communication Networks

“…The asymptotic properties of (17) were proved in our previous study [25]. In this paper, we prove the compactness between (16) and (17) for VLC channels.…”

“…Further, 1/2 is the semi-angle of the LED, FOV is the width of the FOV angle at the PD receiver, and n is a constant for the refractive index. In summary, (1) indicates that a decrease in FOV leads to a decrease in user coverage [9], [25].…”

“…can be used to measure the equivalent VLC user data rate [9], [25], [30]. We provide several reasons for this assertion as follows.…”

“…In [22], the PLS method of GRPA was improved to solve the problem of users with similar channels and accommodate a varying number of users in a MIMO-VLC system. In [23]- [25], various approaches including PLS and FTPA were compared, leading to a re-design of the power allocation strategy in NOMA-VLC networks.…”

A Low-Complexity Resource Allocation Algorithm for Indoor Visible Light Communication Ultra-Dense Networks

“…The reference values for the three characters in VLC-UDNs are provided as follows [7]: the terminal density is higher than 0.25 terminals per m 2 ; the traffic density is higher than 10 Mbps/m 2 ; and the distance between the APs is less than 10 m. Being different from the radio signals in the traditional radio frequency ultra-density networks (RF-UDNs), the visible light in VLC-UDNs has a line of sight (LoS) and it is easily blocked, which interrupts communication [8]. The strong directivity of light sources limits the coverage of a single light source and results in the user channel quality being closely related to the terminal's spatial location [9]. Compared with radio frequency networks, VLC-UDNs have a higher AP density, which would cause increase the prominence of interference in…”