Beam Failure Recovery Resource Reselection in Wireless SCell
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Solution Overview
Problem
In wireless communication systems, especially in Scell environments, beam failure recovery (BFR) procedures face challenges due to limited resources and high latency, leading to inefficient random access resource reselection and potential high power consumption in UE devices when no suitable beams are available for transmission.
Innovation Solution
A method is introduced where a UE initiates a random access resource reselection step in the BFR procedure if no suitable beams are found, utilizing a timer to manage the reselection process, allowing for retransmissions without applying backoff times, thereby preventing indefinite resource reselection and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE continuously performs random access resource reselection when no suitable beams are available, then the beam failure recovery reliability is improved, but the power consumption increases indefinitely
Solution Approach 1:
The patent applies preliminary action by establishing a maximum reselection counter limit before the UE enters indefinite reselection loops. The counter is initialized to a maximum value and decremented with each reselection attempt, preventing excessive power consumption by stopping the process before it becomes unsustainable.
Solution Approach 2:
The patent implements feedback mechanisms through the reselection counter that monitors and controls the number of reselection attempts. When the counter reaches zero, the UE stops reselection and reports beam failure, providing feedback to the network to prevent continuous power-consuming operations without success.
2Reliability
If the UE performs multiple random access preamble transmissions, then the probability of successful beam failure recovery increases, but the latency increases
Solution Approach 1:
The patent applies partial action by limiting the number of random access preamble transmissions to a maximum counter value. Instead of attempting all possible reselections, the UE performs a controlled number of attempts and stops when the counter reaches zero or a suitable beam is found, balancing success probability with latency constraints.
Solution Approach 2:
The patent changes the parameter of transmission count by introducing a decremented counter that controls the number of preamble transmissions. This dynamic parameter adjustment allows the system to adapt between attempting more transmissions for reliability or fewer transmissions for lower latency based on the counter value.
3Adaptability or versatility
If the UE reselects random access resources frequently, then the adaptability to changing beam conditions is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the resource reselection process into discrete, manageable steps controlled by the counter. Each decrement of the counter represents a discrete reselection attempt, making the complex process manageable and easier to control through simple counter operations rather than complex continuous monitoring.
Data Source
AI summary
A method for transmitting signals by a medium access control (MAC) entity of a transmission end in a wireless communication system is disclosed. The method comprises initializing a random access procedure on a secondary cell for beam failure recovery (BFR); transmitting an indication for requesting at least one suitable beam to a lower layer; if information about the at least one suitable beam is not received from the lower layer, incrementing a random access preamble transmission counter; and when the random access preamble transmission counter is less than a maximum value, retransmitting the indication for requesting the at least one suitable beam to the lower layer.