A Spectrum Management Strategy for Visible Light Communications Using an Adaptive Threshold Approach

Abstract

The accessibility of network resources is the primary criteria used to perform handover in existing handover strategies in communication systems. Moreover, the access technique approach implemented in visible light communications (VLC) which utilizes the availability of the channel as the sole criteria for handover instead of the capacity of the channel to support QoE of nodes leads to frequent handovers and poor QoE performance. In this work, the use of adaptive threshold-fixing is proposed to dynamically fix the trigger threshold for handover to match the minimum QoE constraints of the VLC node. Therefore, a node will remain in its current channel as long as the minimum QoE requirements are supported by the present channel. Hence, nodes will only handover if the current channel does not support the least QoE constraints of specific node applications and new channels with better QoE are available. To achieve this, the proposed algorithm dynamically adjusts the handover triggering threshold based on link information extracted from channel at discrete time to meet the minimum QoE constraints of node applications instead of switching to a new available channel. The proposed alogorithm is implemented using Monte Carlo simulations of different VLC scenarios and is compared with a reactive spectrum handoff strategy. Simulations results of the proposed strategies demonstrate a significant reduction of spectrum handoffs while maintaining better throughput for node applications.