Uplink Roaming Queue Control to Prevent Packet Duplication
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Solution Overview
Problem
Wireless communication technologies face issues of packet duplication and out-of-order delivery during station roaming between access points, leading to inefficient resource utilization and increased latency due to redundant transmissions and packet loss.
Innovation Solution
A method and station design that proactively manage uplink data transmission by identifying the last acknowledged sequence number (last ack SN) and dropping failed packets with preceding SNs, then transmitting a second set of packets starting from the next SN, ensuring seamless roaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the station retransmits all unacknowledged packets to the second AP after roaming, then packet delivery reliability is improved, but packet duplication occurs and wireless resources are wasted
Solution Approach 1:
The station performs preliminary actions by dropping failed packets with SNs preceding the last ack SN before roaming occurs. This proactive packet filtering ensures that only relevant packets are transmitted to the second AP, preventing duplication while maintaining reliability.
Solution Approach 2:
The invention extracts and removes unnecessary packets (failed packets with SNs before last ack SN) from the transmitting queue before roaming. This extraction eliminates redundant transmissions that would cause packet duplication and waste wireless resources.
2Reliability
If the station retransmits packets to the second AP after roaming, then packet delivery is maintained, but transmission latency increases due to redundant transmissions
Solution Approach 1:
The station performs preliminary packet filtering by dropping failed packets with SNs preceding the last ack SN before initiating retransmission to the second AP. This preliminary action reduces the number of packets that need to be transmitted, thereby reducing transmission latency while maintaining delivery reliability.
Solution Approach 2:
Instead of retransmitting all unacknowledged packets (excessive action), the invention applies partial action by selectively retransmitting only the packets that need to be sent to the second AP (those with SNs >= last ack SN), optimizing transmission efficiency.
3Loss of substance
If conventional packet filtering approaches are used at the network level, then packet duplication is reduced, but the station still inefficiently retransmits data that the second AP is predetermined to discard
Solution Approach 1:
The station performs self-service by autonomously managing its transmitting queue and making intelligent decisions about which packets to retain and which to drop based on the last ack SN. This self-service mechanism eliminates the need for complex network-level coordination while optimizing transmission efficiency.
Solution Approach 2:
The station performs preliminary filtering of packets locally before transmission, dropping failed packets with SNs before the last ack SN. This preliminary action at the station level prevents inefficient retransmissions of packets that would be discarded by the second AP, improving overall transmission efficiency.
Data Source
AI summary
A roaming method for managing uplink data transmission performed by a station includes transmitting a first set of packets from a transmitting queue of the station to a first access point, updating the transmitting queue, and transmitting a second set of packets from the updated transmitting queue to a second access point after roaming. The packets in the transmitting queue are identified by sequence numbers (SNs). All failed packets remaining in the transmitting queue that have SNs preceding the last ack SN are dropped for a roaming scenario. The second set of packets starts with a packet having an SN subsequent to the last ack SN. The last ack SN is defined as a specific SN of the last packet indicated as successfully received by the first access point.