Channel allocation method in d2d communication coexisting with wifi in unlicensed frequency band

Abstract

The present invention provides a channel allocation method in D2D communication where an unlicensed frequency band and WiFi coexist. The method mainly includes: clustering the D2D-U devices coexisting with WiFi based on the distance, assigning a cluster head to each cluster, and the cluster head of each cluster according to the monitoring results of the surrounding spectrum environment by the D2D-U device members in the cluster, Dynamically select the currently used channel of its cluster, and the cluster head uses a competition mechanism to obtain the right to use the currently used channel on behalf of its cluster, and allocates the resources of the currently used channel to each D2D-U device in the cluster for use. The present invention aims at the randomness of WiFi AP positions and WiFi AP working channels. By dividing D2D-U devices into several disjoint clusters, and dynamically adjusting the working channels in the clusters according to the spectrum environment, not only makes full use of the idle spectrum At the same time, it can reduce the channel interference between D2D-U devices and between D2D-U devices and WiFi users, and improve the performance of communication links as much as possible.

Description

technical field [0001] The present invention relates to the technical field of wireless communication, in particular to a channel allocation method in D2D communication where an unlicensed frequency band and WiFi coexist. Background technique [0002] With the rapid development of D2D (Device to Device, device to device) business and LTE-U (LTE in Unlicensed Spectrums, LTE in unlicensed frequency band) technology, the integration of D2D and LTE-U is an inevitable trend of future communication development. An important application scenario in the fifth generation mobile communication (5G). However, the initial WiFi and D2D networks are designed to operate in different frequency bands. To deploy D2D in unlicensed frequency bands, the differences between WiFi and D2D communications must be considered. [0003] The characteristics of the WiFi (Wireless Fidelity, wireless fidelity technology) system are as follows: [0004] The WiFi system is deployed in the unlicensed frequenc...

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Problems solved by technology

[0008] WiFi system can only be used for short distance communication

The channel fading in the 5GHz unlicensed frequency band is very large, and the agreement stipulates that the transmit power on the unlicensed frequency band is limited

[0016] 1. Channel selection problem: The 802.11 protocol itself does not regulate how nodes select channels in the initial stage of the network. The default mechanism will make WiFi APs randomly work on a certain channel

However, in actual deployment, because the 802.11 protocol has no clear channel selection specification, the channel selected by the WiFi AP is also relatively random.

With the increase in the number of WiFi APs and WiFi terminals, the channel selection of D2D-U devices is more complicated than the above situation, and channel reuse is inevitable, but the WiFi system does not have a regular cell shape and planned coverage like the LTE system Range, the installation position of WiFi AP is relatively random, it can be placed arbitrarily according to the needs of the owner, and the channels used are also random, so it is much more difficult for D2D-U devices to achieve channel multiplexing in unlicensed frequency bands than in cellular networks

As of now, there is no effective channel selection mechanism to guarantee the coexistence of D2D-U devices and WiFi users

[0019] 2. Channel access problem: The opportunity for D2D-U devices to access unlicensed frequency band channels is limited by the WiFi system using the 802.11CSMA / CA mechanism. D2D-U devices will not perform channel detection before communicating. If they directly access the channel, it will cause WiFi System performance is significantly reduced;

[0020] After research, although D2D-U devices use the LBT competition mechanism to ensure the fairness of WiFi user access channels, but for scenarios where D2D-U devices are densely deployed such as commercial areas, each D2D-U device uses the LBT competition mechanism to compete with each other. Interference and competition will greatly reduce the success rate of WiFi and D2D-U devices accessing channels, affecting network throughput

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