Scheduling Request Management in Unlicensed Bands
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Solution Overview
Problem
Conventional wireless communication systems experience inefficiencies and delays when operating in unlicensed frequency bands due to restrictions like Listen-Before-Talk (LBT) rules, which cause unnecessary delays in scheduling requests for multiple logical channels.
Innovation Solution
User equipment determines the priority level of logical channels and initiates timers only for low-priority channels, allowing high-priority channels to transmit scheduling requests at the next available opportunity, thereby reducing delays and improving data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional systems automatically initiate timers for both logical channels when a scheduling request is transmitted for one radio resource, then channel access control is maintained, but transmission delay increases for high-priority data
Solution Approach 1:
The patent applies different timer initiation rules to different logical channels based on their priority levels. High-priority logical channels do not have timers initiated, allowing immediate retransmission attempts, while low-priority channels have timers initiated to control access. This local differentiation resolves the contradiction by eliminating unnecessary delays for high-priority data while maintaining control for low-priority channels.
Solution Approach 2:
The patent segments the logical channels into high-priority and low-priority groups, applying different scheduling request management rules to each segment. This segmentation allows the system to optimize for speed in high-priority channels while maintaining control mechanisms in low-priority channels, thereby reducing overall transmission delay without compromising system stability.
2Productivity
If multiple scheduling requests are transmitted simultaneously on different MA channels, then resource allocation efficiency improves, but channel contention and collision probability increase
Solution Approach 1:
The patent changes the parameter of timer initiation based on logical channel priority. By not initiating timers for high-priority channels, the system allows more aggressive access attempts, improving resource allocation efficiency for critical data. The timer mechanism remains active for low-priority channels to prevent excessive contention, thus balancing efficiency and reliability.
3Reliability
If timers are initiated for all logical channels to control access, then channel contention is reduced, but transmission speed decreases
Solution Approach 1:
The patent applies timer control selectively based on local channel priority characteristics. High-priority channels receive expedited treatment without timer constraints, maximizing transmission speed for critical data. Low-priority channels maintain timer-based control to reduce contention. This local quality approach resolves the contradiction by applying different control intensities to different channels based on their importance.
Data Source
AI summary
This document describes techniques and apparatuses for managing scheduling requests in an unlicensed frequency band. These techniques include a user equipment receiving first and second configuration messages allocating radio resources for first and second logical channels, respectively, at a scheduling request (SR)-transmission occasion on first and second multiple-access (MA) channels, respectively, in the unlicensed frequency band (402, 404). In aspects, the user equipment detects that the first MA channel is busy and the second MA channel is idle (406). The user equipment transmits a scheduling request via the second radio resource (408) and initiates a timer for the second logical channel to prohibit transmission of an additional scheduling request via the second radio resource until expiration of the timer (410). The user equipment also determines whether to initiate another timer for the first logical channel based on a priority level of the first logical channel (414).