PRNG Backoff Counter Synchronization for Wireless Channel Access
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Solution Overview
Problem
In wireless communication systems, especially in NR-U, the randomness of the backoff time in the Listen-before-talk (LBT) procedure limits scheduler efficiency due to unknown backoff times among network transmitters, leading to potential collisions and inefficient channel access.
Innovation Solution
Implementing a pseudo random number generator (PRNG) with a shared seed between base stations and user devices to determine and manage random backoff counters, ensuring synchronized and efficient channel access by estimating the duration of transmission deferral and average delay, thereby improving scheduling decisions and reducing unnecessary channel monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a random backoff time is used in the Listen-before-talk procedure, then channel access randomness is achieved to avoid collisions, but scheduler efficiency deteriorates due to unknown backoff times
Solution Approach 1:
The patent implements feedback by having the base station signal the selected backoff time to the user device. This allows the user device to know its backoff time while maintaining randomness through the base station's selection process, thereby improving scheduler efficiency without compromising collision avoidance
Solution Approach 2:
The base station acts as an intermediary that selects the backoff time and communicates it to the user device. This intermediary role allows the system to maintain the benefits of random backoff while enabling the scheduler to make informed decisions about channel access timing
2Reliability
If backoff time is kept random and unknown to the base station, then collision avoidance is maintained, but channel monitoring requirements increase
Solution Approach 1:
By having the base station signal the backoff time to the user device, the system reduces the need for continuous channel monitoring by the base station. The user device can independently manage its backoff counter based on the provided information, simplifying the overall system complexity
3Device complexity
If the base station does not know the backoff time, then implementation simplicity is maintained, but power consumption increases due to continuous monitoring
Solution Approach 1:
The feedback mechanism where the base station signals the backoff time to the user device allows the base station to reduce continuous channel monitoring, thereby lowering power consumption while maintaining implementation simplicity
Solution Approach 2:
The user device uses the provided backoff time information to independently manage its own transmission timing, reducing the base station's monitoring burden and associated power consumption
Data Source
AI summary
A user device, UE, for a wireless communication system according to an embodiment is provided. A backoff rule is stored within a storage of a base station and within a storage of the user device. Or, the user device is to transmit the backoff rule to the base station. Or, the user device is to receive the backoff rule from the base station. The user device is to determine a random backoff counter depending on the backoff rule. Moreover, the user device is to decrement the random backoff counter if a transmission channel is not occupied for a certain duration. Furthermore, the user device is to transmit a data packet via the transmission channel, if the random backoff counter reaches a predefined value.