Uplink OFDMA Random Access Backoff for Collision Reduction
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Solution Overview
Problem
Existing wireless LAN systems face challenges in providing high-efficiency and high-performance communication in high-density environments, particularly in managing the random access procedure of multiple terminals effectively.
Innovation Solution
A wireless communication terminal and method that utilize a backoff counter within a contention window for uplink multi-user random access, decrementing the counter based on resource units indicated by a trigger frame, and performing uplink multi-user transmission through selected resource units, with carrier sensing to ensure channel availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple terminals perform random access simultaneously in high-density environments, then the system can support more users and improve productivity, but the collision probability increases and channel access efficiency deteriorates
Solution Approach 1:
The channel access mechanism is segmented into two distinct phases: a random access phase for initial channel contention and a scheduled access phase for subsequent data transmission. This segmentation allows terminals to efficiently contend for channel access initially, then transition to a more organized scheduled access mode, reducing collisions and improving overall channel access efficiency in high-density environments.
Solution Approach 2:
The access point performs preliminary actions by sending a trigger frame that schedules specific resource units for random access before the actual data transmission. This preliminary scheduling organizes the random access process, allowing terminals to know in advance which resource units they can use, thereby reducing collisions and improving channel access efficiency while supporting multiple simultaneous users.
2Productivity
If traditional contention-based channel access is used, then the system is simple to implement, but resource utilization rate is low and access efficiency deteriorates in high-density scenarios
Solution Approach 1:
The channel access mechanism dynamically transitions between two modes: random access mode for initial channel contention and scheduled access mode for organized data transmission. This dynamic adaptation allows the system to maintain simplicity during initial access while achieving high resource utilization during data transmission, effectively balancing complexity and productivity in high-density environments.
Solution Approach 2:
The trigger frame acts as an intermediary that mediates between the access point and multiple terminals. It carries scheduling information that organizes random access resource units, enabling coordinated access without requiring complex distributed coordination among terminals. This intermediary mechanism improves resource utilization while keeping the overall system complexity manageable.
Data Source
AI summary
Provided are a wireless communication terminal including: a processor; and a communication unit, wherein the processor obtains a backoff counter for an OFDMA-based random access of the terminal, wherein the backoff counter is obtained within a range of a contention window for the uplink OFDMA-based random access, receives a trigger frame indicating an uplink multi-user transmission, when one or more resource unit(s) in which random access can be performed is indicated by the trigger frame, decrements the backoff counter based on a number of resource units(s) in which random access can be performed, and when the backoff counter is 0 or decremented to 0, performs an uplink multi-user transmission through a selected resource unit among the resource units(s) and a wireless communication method using the same.