Client, access point, communication system and switching method

Abstract

The embodiment of the invention provides a client, an access point, a communication system and a switching method. When the client moves close to a first access point and then close to the second access point and is located in a commonly coverage range of the first and second access points, a signal receiving module is used for receiving signals from the first and second access points through an omnidirectional antenna. A switching condition judging module judges whether the switching condition is met or not according to the signal strength of the signal received at the first access point or the signal strength of signals received at the first and second access points. If so, a switching command is sent to a switch executing module. The switch executing module is used for starting a switching program to switch the client from the first access point to the second access point according to the switch executing command. The client, the access point, the communication system and the switching method ensure the switching reliability.

Description

technical field [0001] The present invention relates to wireless communication technology, in particular to a client, an access point, a communication system and a switching method. Background technique [0002] Due to the advantages of wireless communication-based subway control and passenger information systems, such as continuous two-way connection, high data transmission rate, and low cost, the system is attracting more and more attention nowadays. Taking the wireless subway communication system based on wireless local area network (WLAN) as an example, some access points (APs) are arranged along the railway track, and a client is set at the train end. The client on the train and the equipment beside the track can exchange information. [0003] figure 1 It is a schematic structural diagram of a wireless local network including a switching mechanism in the prior art. Such as figure 1 As shown, access points AP are set up along the subway track from left to right i-1 ...

AI Technical Summary

Problems solved by technology

The determination of the place to start switching depends on the determination of the RSSI threshold, but the propagation process of wireless signals, that is, electromagnetic waves, is affected by various environmental factors around. In fact, it is difficult to determine an accurate RSSI threshold for each access point

[0007] From this it can be seen that in figure 2 In the illustrated embodiment, since the client's forward antenna i The signal strength of the signal received by the rear-facing antenna will drop sharply. It is necessary to ensure that the client has enough time to receive the signal from the AP. i Switch to AP i+1 , you need to accurately determine the RSSI threshold to accurately determine where to start switching, but the RSSI threshold is difficult to accurately determine

Once the determined RSSI threshold is inappropriate, the client cannot i Switch to AP i+1 on, the reliability of switching cannot be guaranteed

In addition, the switching quality is not high and the system cost is high

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