Parallel Random Access Preamble Transmission for NR Beam Sweeping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE systems, user equipment (UE) can only perform one random access procedure at a time, limiting the ability to reduce the total time of the procedure and increase the chances of successful random access response reception and contention resolution, especially with the introduction of New Radio Access Technology (NR) requiring beam forming and beam sweeping for higher frequency bands.
Innovation Solution
The method involves transmitting multiple random access preambles in parallel for a single random access procedure, with the UE monitoring responses across multiple reception windows and retransmitting if initial responses are unsuccessful, allowing for efficient beam sweeping support in NR systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If multiple random access preambles are transmitted in parallel for a single random access procedure, then the total time of the random access procedure is reduced and the chances of successful response reception are increased, but the device complexity and protocol management complexity increase
Solution Approach 1:
The random access procedure is segmented into multiple parallel preamble transmission attempts, each with its own response reception window. The UE transmits multiple preambles (e.g., preamble 1, preamble 2, etc.) in parallel rather than sequentially, and monitors for responses independently for each preamble transmission. This segmentation allows time reduction through parallelism while maintaining manageable complexity through structured organization of transmission and monitoring events.
2Reliability
If multiple random access preambles are transmitted in parallel, then the reliability of random access response reception is improved, but the quantity of transmitted signals and monitoring operations increases
Solution Approach 1:
The UE performs preliminary actions by transmitting multiple random access preambles in parallel at the outset of the random access procedure, rather than transmitting them sequentially. Each preamble is transmitted with its associated uplink data, and the UE monitors for multiple random access responses in parallel. This preliminary parallel action increases the probability that at least one preamble will be successfully received and decoded, thereby improving reliability without requiring sequential retry mechanisms.
3Reliability
If beam sweeping is implemented for higher frequency bands in NR systems, then the coverage and signal quality are improved, but the time required for random access procedure increases
Solution Approach 1:
The patent implements periodic action through beam sweeping, where the UE transmits random access preambles using different beam directions in a periodic sequence. Each beam transmission opportunity allows for potential random access response reception. By organizing beam sweeping into periodic transmission frames with multiple beam directions, the system maintains improved coverage and signal quality while managing the overall procedure duration through structured periodic repetitions rather than unstructured sequential scanning.
Data Source
Figure 1
Figure 2
Figure 3~3(b)
AI summary
A method for a user equipment (UE) performing random access to a network comprises: receiving configuration information from a network; determining multiple number of random access preamble transmission occasions with regards to a prioritized event based on the configuration information; monitoring a random access response after an end of a random access preamble transmission based on the multiple random access preamble transmission occasions until a specific random access response window ends, wherein a starting time of the specific random access response window is based on a last one of the multiple number of random access preamble transmission occasions; and processing a retransmission of the random access preamble transmission, if the random access response is not received until the specific random access response window ends.