Scheduling Request Prohibit Timer for PUCCH Load Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE wireless communication systems, the scheduling request periodicity in the uplink direction leads to significant unnecessary load on the Physical Uplink Control Channel (PUCCH) due to repeated transmissions, which increases access delay and interferes with other user equipment transmissions, failing to meet the low latency requirements of IMT Advanced networks.
Innovation Solution
Implementing a scheduling request prohibit timer in user equipment to prevent early retransmissions of scheduling requests, allowing transmissions only at predetermined opportunities, thereby reducing PUCCH load and distributing retransmissions in time, and configuring different timer lengths for various user equipment to avoid collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If scheduling request periodicity is set to short value to reduce access delay, then access delay is improved, but load on PUCCH increases significantly due to repeated transmissions
Solution Approach 1:
The patent implements a prohibit timer that creates periodic transmission opportunities for scheduling requests. Instead of continuous or frequent periodic transmissions, the timer enforces a prohibited period after each scheduling request transmission, allowing only periodic retransmissions when the timer expires. This transforms the transmission pattern from high-frequency periodic to controlled periodic, reducing overall transmission load while maintaining access responsiveness.
Solution Approach 2:
The prohibit timer is configured in advance with a specific duration before scheduling request transmissions occur. This preliminary timing configuration prevents immediate retransmissions and distributes transmissions over time. The timer value is predetermined and applied before each transmission opportunity, proactively controlling the transmission rate to balance access delay requirements with channel load reduction.
2Loss of time
If scheduling request periodicity is reduced to meet latency requirements, then latency is improved, but interference with other user equipment transmissions increases
Solution Approach 1:
The prohibit timer enforces periodic gaps between scheduling request transmissions from the same user equipment. This periodic structure distributes transmissions in time, reducing collision probability with other user equipment. The timer creates a rhythmic transmission pattern that naturally spacing out interference events, allowing other UEs to transmit during prohibited periods without experiencing continuous interference.
Solution Approach 2:
The prohibit timer duration is configured in advance to preemptively avoid interference scenarios. By setting the timer before transmissions occur, the system proactively prevents potential interference events rather than reacting to them. The preliminary timing configuration ensures that retransmissions are spaced out before interference problems can arise, reducing overall interference impact on the system.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Method and arrangement in a user equipment for transmitting scheduling requests to a base station. The base station is adapted to serve the user equipment. The user equipment is configured to transmit scheduling requests to the base station only at certain predetermined scheduling request opportunities. The method comprises triggering a scheduling request transmission, transmitting a scheduling request to the base station at the next occurring scheduling request opportunity, starting a scheduling request prohibiting timer and prohibiting any further scheduling request retransmission at future scheduling request opportunities while the scheduling request prohibiting timer is running. Also, a corresponding method and arrangement in a base station is described.