Random Access BWP Switching to Prevent RAR Reception Failure
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Solution Overview
Problem
In wireless communication systems, mismatch between active DL/UL BWP at UE and gNB during ongoing random access procedures leads to data interruption, particularly when SR transmission is cancelled, and inappropriate DL BWP selection results in RAR reception failures.
Innovation Solution
Methods and apparatuses are provided to manage BWP switching by terminating ongoing random access procedures and switching back to the original BWPs upon cancellation, ensuring alignment between UE and gNB BWPs, particularly for SpCell and SCell operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a user equipment simultaneously transmits and receives signals in the same frequency band, then spectrum utilization efficiency is improved, but self-interference occurs between transmission and reception signals
Solution Approach 1:
The frequency band is divided into multiple sub-bands or resource blocks, allowing the user equipment to transmit and receive signals in different portions of the frequency spectrum simultaneously. This segmentation prevents self-interference by spatially separating the transmit and receive frequency resources while maintaining high spectrum utilization.
Solution Approach 2:
A self-interference cancellation mechanism is introduced as an intermediary process. The system generates an estimate of the self-interference signal and subtracts it from the received signal, effectively canceling out the harmful interference and enabling simultaneous transmit and receive operations in the same frequency band.
2Productivity
If downlink data transmission is performed during random access procedure, then communication efficiency is improved, but collision between random access preamble and downlink signal occurs
Solution Approach 1:
The system performs downlink signal transmission in advance during the random access procedure, allowing the user equipment to receive and process downlink data before completing the random access handshake. This preliminary action optimizes resource utilization while the collision risk is managed through proper timing and resource allocation.
Solution Approach 2:
The system dynamically adjusts the timing and resource allocation for downlink transmission during the random access procedure. By making the downlink transmission opportunity conditional and adaptable based on the random access state, the system can efficiently utilize resources when conditions permit while avoiding collisions when they would occur.
Data Source
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AI summary
Methods and apparatuses for performing communication in a wireless communication system are provided. The method, performed by a user equipment (UE), of performing the communication in the wireless communication system, according to an embodiment, includes identifying an ongoing random access (RA) procedure triggered for a pending scheduling request (SR) transmission, identifying whether an active uplink bandwidth part (UL BWP) or an active downlink bandwidth part (DL BWP) is switched at an initiation of the ongoing RA procedure and performing an operation of switching the active UL BWP or the active DL BWP to an initiation BWP or an operation of terminating the ongoing RA procedure based on a result of the identification.