Random Access Contention Resolution for Low-Power Reduced-Capability UEs
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing radio resource configuration and UE power consumption, particularly for reduced capability UEs, leading to increased latency and power consumption during random access procedures and data transmission.
Innovation Solution
Implementing improved random access procedures for reduced capability UEs that allow early detection of contention resolution failures, optimizing Buffer Status Report (BSR) table selection, and aligning Connected Discontinuous Reception (C-DRX) configurations with service periodicity to reduce latency and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the frequency domain resource allocated to the message is increased, then the reliability of contention resolution is improved, but the power consumption of the UE increases
Solution Approach 1:
The UE performs partial decoding of the message by checking only the frequency domain resource allocation indicator against its allocated resources, rather than fully decoding the entire message. This partial action approach allows the UE to detect allocation failures quickly without consuming excessive power, resolving the contradiction between reliability and power consumption.
Solution Approach 2:
The UE autonomously determines whether the message is allocated to it by comparing the frequency domain resource indicator with its allocated resources, and self-manages the contention resolution process by deciding whether to continue or restart the random access procedure. This self-service mechanism reduces power consumption by eliminating unnecessary full decoding operations.
2Reliability
If the message decoding complexity is increased to ensure successful decoding, then the reliability of contention resolution is improved, but the latency of the random access procedure increases
Solution Approach 1:
The UE performs partial verification of message allocation by checking only the frequency domain resource indicator, rather than performing complete message decoding. This partial action approach maintains sufficient reliability for contention resolution while significantly reducing the time required, thus resolving the contradiction between reliability and latency.
Solution Approach 2:
When the UE determines that the message is not allocated to it (based on frequency domain resource mismatch) or that contention resolution has failed, it skips the remaining decoding steps and immediately restarts the random access procedure. This skipping mechanism reduces overall latency by avoiding unnecessary processing steps.
3Measurement precision
If the BSR table size is increased to provide more granular buffer status reporting, then the precision of buffer status information is improved, but the device complexity increases
Solution Approach 1:
The system dynamically selects between different BSR table configurations (first BSR table with coarser granularity, second BSR table with finer granularity) based on service requirements and UE capabilities. This dynamic adaptability allows the system to achieve high precision when needed while maintaining lower complexity for other scenarios, resolving the contradiction between precision and device complexity.
Solution Approach 2:
The patent introduces configurable parameters (such as bsr-TableIndicator) that allow dynamic adjustment of BSR table selection and granularity. By changing these parameters based on service type and UE capability, the system can optimize between precision and complexity without being constrained by a fixed table structure.
4Use of energy by moving object
If the C-DRX periodicity is decreased to improve power saving, then the energy consumption is reduced, but the latency for service data transmission increases
Solution Approach 1:
The system dynamically adjusts C-DRX configuration parameters (drx-OnDurationTimer, drx-InactivityTimer, drx-SlotOffset) based on service periodicity and data arrival patterns. This dynamic configuration allows the UE to achieve power saving through extended sleep periods while ensuring that the network can wake the UE in time for urgent data transmissions, resolving the contradiction between power consumption and transmission latency.
Solution Approach 2:
The network performs preliminary configuration of C-DRX parameters based on expected service patterns and periodicity. By pre-configuring appropriate timer values and wake-up schedules, the system prepares the UE for both power-saving operation and timely data reception, eliminating the need for frequent configuration changes and reducing overall latency.
Data Source
AI summary
This disclosure relates generally to a method, device, and system for random access. One method performed by a wireless device may include: initiating a random access procedure with a wireless communication node; receiving control information carrying scheduling information for reception of a message carrying contention resolution information, the scheduling information indicating a frequency domain resource allocated to the message, and the contention resolution information indicating whether a contention resolution associated with the random access procedure is successful; and in response to one of: the frequency domain resource allocated to the message being larger than a threshold; or the message being unable to be decoded successfully, performing at least one of: considering the contention resolution to be unsuccessful; stopping a contention resolution timer associate with the random access procedure; discarding a temporary C-RNTI assigned by the wireless communication node for the random access procedure; or triggering another random access procedure.