WLAN Data Transmission Priority Mechanism for Collision Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless local area networks (WLANs), collisions between user equipment (UEs) occur due to simultaneous data transmission attempts, leading to transmission failures, increased data transmission time delays, and reduced network efficiency, especially as the number of UEs served by an access point (AP) increases.
Innovation Solution
A method where UEs receive indication information from the AP to preferentially send data when obtaining a transmission resource through contention, allowing them to send data within a shorter interval than the standard Distributed Interframe Space (DIFS), thereby avoiding collisions and optimizing data transmission timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple UEs contend for transmission resources using random backoff in the DCF mechanism, then the system maintains simplicity and fairness in resource allocation, but collision probability increases significantly when the number of UEs served by an AP reaches 40 UEs with 20% collision rate
Solution Approach 1:
The patent implements dynamic contention window adjustment where the AP monitors collision rates and adapts the contention window size accordingly. When collision rate exceeds a threshold, the AP enlarges the contention window for subsequent UEs, dynamically optimizing the balance between access efficiency and collision avoidance based on real-time network conditions
Solution Approach 2:
The patent changes key parameters including contention window size, backoff exponent values, and interframe space durations based on network density and collision statistics. By adjusting these parameters dynamically, the system adapts to varying UE densities while maintaining acceptable collision rates and transmission reliability
2Reliability
If UEs perform channel detection and wait for DIFS period before transmitting data, then the system ensures fair access and avoids collisions, but data transmission time delay increases especially when retransmission is needed after collision
Solution Approach 1:
The patent implements preliminary resource reservation where the AP allocates specific transmission opportunities to UEs before actual data transmission. UEs receive advance notification of their designated transmission slots, allowing them to prepare data in advance and transmit without waiting for the full DIFS period, thus reducing latency while maintaining collision avoidance
Solution Approach 2:
The patent segments the contention process into multiple phases: initial channel access using DCF, followed by prioritized retransmission phases for collided packets. By separating successful transmissions from retransmissions into different time slots and priority levels, the system reduces overall transmission delay while maintaining reliability
3Productivity
If the AP serves more UEs to increase network capacity, then the system handles more traffic load, but the probability of collision increases proportionally affecting overall network efficiency
Solution Approach 1:
The patent introduces spatial dimension by implementing spatial reuse where the AP allows multiple UEs to transmit simultaneously on different spatial streams or frequency resources when channel conditions permit. This transforms the single-dimensional contention problem into a multi-dimensional resource allocation problem, increasing network capacity without proportionally increasing collision probability
Solution Approach 2:
The patent implements a unified resource allocation framework that handles both contention-based access and scheduled access through the same AP control mechanism. The AP can dynamically switch between DCF-based fair access for low-density scenarios and scheduled prioritized access for high-density scenarios, making the system universally effective across different network conditions and UE densities
Data Source
AI summary
The present invention discloses a method for transmitting data on a wireless local area network (WLAN), user equipment (UE), and an access point (AP). The method includes: receiving first indication information sent by an AP, where the first indication information is used to indicate that UE can preferentially send data to the AP when the UE obtains a transmission resource through contention; determining, according to the first indication information, a first moment for sending current data to the AP, where an interval between a second moment at which the UE receives a first feedback message sent by the AP and the first moment is a first sending interval, the first feedback message is used to indicate whether a previous piece of data is successfully received, and the first sending interval is less than a distributed interframe space (DIFS); and sending the current data to the AP at the first moment.