Method for realizing cross-channel roaming switching of wireless terminal in WLAN

Abstract

The invention provides a method for realizing cross-channel roaming switching of a wireless terminal in a WLAN. The WLAN network is at least formed by one SDN controller and a plurality of programmable APs, the adjacent APs work on different channels, and each AP is provided with two same-frequency wireless network cards. When the wireless terminal is far away from an original AP, a controller firstly adjusts an auxiliary wireless network card channel of a neighbor AP of the controller to a wireless terminal work channel in order to acquire a signal intensity value of the wireless terminal; secondly, one neighbor AP is selected as a switching target AP through a switching strategy, and a virtual AP is transferred to a target AP; and finally, the original AP is commanded to issue a channelswitching announcement. After the wireless terminal receives the channel switching announcement, the wireless terminal switches the channel to the target AP channel. After the channel is switched, thewireless terminal can directly transmit user data with a new AP. The wireless terminal only needs to switch the channel in the whole switching process, and the time is within a few milliseconds, so that a purpose of fast cross-channel roaming switching of the wireless terminal in the WLAN is achieved.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to a method for realizing roaming switching of a wireless terminal in a WLAN. Background technique [0002] According to the IEEE 802.11 specification, a terminal (STA) working in the infrastructure mode and its associated access point (Access Point, AP) together form a basic service set (BSS). In the basic service set, the wireless terminal must establish an Only after being associated can it communicate with other nodes, that is, the data transmission between the wireless terminal and other nodes must be forwarded by the AP. Because in a basic service set, the network coverage of AP is very limited, usually within 200 meters. Such a small transmission distance limits the mobile range of the wireless terminal. [0003] In this regard, the coverage of the network is generally extended by increasing the number of APs in the network. Connect multiple APs together ...

AI Technical Summary

Problems solved by technology

[0005] However, there are several main problems in the current standard: one is that the two APs for fast switching need to be on the same channel. Terminals are constantly switched between APs, which not only affects terminal services, but also seriously consumes AP performance

The second problem is that the fastest switching time based on the 802.11r standard modification is limited to a theoretical 50ms, which is not enough for some real-time multimedia services

The third problem is that these handover decisions are made by wireless terminals, but due to the diversity of wireless terminals, some terminals do not support related 802.11 handover protocols, which makes it difficult for WLAN networks to provide unified services for all wireless terminals. more complicated

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