Visible Light Communication (VLC) using Light Emitting Diodes (LEDs) within the existing lighting infrastructure can reduce the implementation cost and may gain higher throughput than radio frequency (RF) or Infrared (IR) based wireless systems. Current indoor VLC systems may suffer from poor downlink resource allocation problems and small system throughput. To address these two issues, we propose an algorithm called a conflict graph scheduling (CGS) algorithm, including a conflict graph and a scheme that is based on the conflict graph. The conflict graph can ensure that users are able to transmit data without interference. The scheme considers the user fairness and system throughput, so that they both can get optimum values. Simulation results show that the proposed algorithm can guarantee significant improvement of system throughput under the premise of fairness.

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IntroductionWith the rapid development of Internet and the quick emergence of mobile Internet, clouding computing [2], Internet of things [3], the problem of Future Internet constantly occurs [4], such as the problems of Internet mobility, routing scalability, multi-homing and security. Many solutions are put forward to satisfy the need of future Internet network, for example, virtualization network topology [5], redesign content centric network architecture [6], and split resource identifier and locator [7], etc. What identifier and locator split means is to represent the double semantic of IP with identifier and locator respectively. At present, the identifier and locator split architecture, for which the realization of resource identifier mapping service system [8] is of great importance, is widely studied by worldwide researchers. The core issue to realize the resource identifiers mapping system is its resource mapping and searching algorithm, which should be able to satisfy scalability, mass data mapping, update and inquiry, etc.In the P2P system, the DHT-based resource searching method includes Chord [10], CAN [11], Pastry [12] and Tapestry [13] in the P2P structured network. The Chord based method has the advantage of self-organization, scalability, robustness and rapid inquiry for its distributed hash table based identifier mapping system. So, the technology of Chord may become one of the promising candidate technologies for the resource searching of future Internet network. But in the future Internet network, the issues of scalability, quick inquiry, high frequency mapping and data update will rise in the resource mapping service system for there will be mass data and application in it. It is found that one of three or so the indexes in the Chord routing table are repetitive, which reduces the inquiry efficiency and increases the hops of inquiry [14]. Moreover, a small number of nodes with hotspot information are visited most often than the vast majority of information access nodes, which leads to long-tail effect of inquiry data [15] and increases the inquiry average hops and delay. Taking full advantage of Chord, the Future Network Chord (FN Chord), an improved algorithm of resource identifier mapping and searching in identifier and locator split future network, is put forward to decrease the average inquiry delay and the average inquiry hops in the paper. The improved algorithm based on interest index table in the future network Chord is proposed to solve the long-tail effect problem