Central AP Coordinated Handover for Distributed Access Points
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Solution Overview
Problem
In wireless local area networks, handovers between access points cause temporary disconnections, leading to packet loss and service interruptions, especially for voice and video services, which degrade user experience.
Innovation Solution
A method where a central AP coordinates handovers between distributed APs by sending instructions to switch from receiving to listening mode during handovers, ensuring no data frame loss and avoiding acknowledgement collisions, using sequence numbers to detect duplicate frames and optimize network resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the wireless terminal disconnects from the former AP to connect to the latter AP during handover, then the wireless terminal can move between coverage areas, but packet loss occurs leading to service interruption
Solution Approach 1:
The target distributed AP is pre-configured with the wireless terminal's information and starts receiving data frames before the handover is complete. The source distributed AP continues to forward data frames to the target AP during the transition, ensuring no packet loss occurs while the terminal switches APs.
Solution Approach 2:
The central AP acts as an intermediary that coordinates the handover process between source and target distributed APs. It sends instructions to both APs to ensure seamless data frame forwarding and manages the transition to prevent service interruption.
2Reliability
If multiple distributed APs simultaneously return acknowledgement frames during handover, then data reception is confirmed, but acknowledgement frame collisions occur
Solution Approach 1:
The target distributed AP is pre-instructed by the central AP to skip returning acknowledgement frames during the handover transition period. This prevents acknowledgement frame collisions while ensuring data frames are still received and forwarded properly.
Solution Approach 2:
The acknowledgement frame return behavior dynamically changes during handover. The target AP transitions from not returning acknowledgements (during initial handover) to returning acknowledgements (after handover completion), controlled by instructions from the central AP.
Data Source
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AI summary
A method for handover between distributed access points is disclosed. A central AP makes a handover decision on a wireless terminal, and when the wireless terminal meets a handover condition, determines that the wireless terminal is handed over from an AP 1 to an AP 2, and sends a first instruction to the AP 2. The first instruction includes an identifier of the wireless terminal, and the first instruction is used to instruct the AP 2 to start receiving a data frame from the wireless terminal, and forbid the AP 2 to return an acknowledgement frame to the wireless terminal. The central AP sends a handover success notification message to the AP 1 and the AP 2. The handover success notification message includes the identifier of the wireless terminal, and the handover success notification message is used to instruct the AP 1 to stop receiving the data frame from the wireless terminal, and is used to instruct the AP 2 to return the acknowledgement frame to the wireless terminal. In a handover process, it is ensured that no data frame sent by the wireless terminal during the handover between the AP 1 and the AP 2 is lost, and service interruption is avoided. In addition, a collision among multiple acknowledgement frames can be avoided.