Random Access Resource Allocation With Cyclic Shift Collision Handling
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Solution Overview
Problem
In wireless communications systems, random access procedures can result in collisions due to multiple user equipments selecting the same preamble, leading to extended delays, system latency, inefficient resource use, and decreased throughput, especially when cyclic shift dithering is applied by UEs, causing network entities to erroneously identify collisions.
Innovation Solution
User equipments apply cyclic shift dithering to detect potential collisions based on network-provided information and UE information, determining whether a collision has occurred within a specific cyclic shift step size, and adjust their transmissions accordingly to avoid resource conflicts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cyclic shift dithering is applied by UEs to differentiate transmissions, then collision detection capability is improved, but network entities erroneously identify collisions due to timing variations
Solution Approach 1:
The network entity acts as an intermediary that receives timing information from multiple UEs and processes it to determine actual collisions. The network entity mediates between the cyclic shift dithering applied by UEs and the collision detection function, using the timing information to distinguish between legitimate collisions and apparent collisions caused by dithering variations.
Solution Approach 2:
The system implements feedback by having UEs report their timing information to the network entity, which then uses this feedback to accurately determine whether collisions have occurred. The network entity processes the timing feedback from multiple UEs to make informed collision detection decisions, reducing erroneous identifications.
2Productivity
If multiple UEs select the same preamble for random access, then resource utilization is improved, but collisions occur leading to extended delays and reduced throughput
Solution Approach 1:
The patent replaces the traditional mechanical collision detection method with a timing information-based detection mechanism. Instead of relying solely on signal collision patterns, the system uses reported timing information from UEs to detect and resolve collisions, enabling more efficient handling of multiple UEs selecting the same preamble.
3Adaptability or versatility
If cyclic shift step size is increased to cover RTT variations, then timing coverage is improved, but collision detection precision deteriorates
Solution Approach 1:
The system dynamically adjusts the cyclic shift step size based on the specific timing conditions and RTT variations observed. Rather than using a fixed step size, the network entity can adapt the step size to match the actual timing spread of UE transmissions, maintaining both coverage and precision in different operational scenarios.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may apply a cyclic shift (CS) dither to a preamble transmission. A network entity may transmit a response message which indicates a list of detected random access paths (e.g., corresponding to potentially colliding preambles), an indication of resources for transmitting another random access message, and a grant of resources for transmitting another preamble. The UE may determine a quantity of random access paths occurring within a CS step size from the transmission of the preamble according to the applied CS dithering. If a collision is detected, the UE may transmit another preamble via the resources indicated for another preamble. If no collision is detected, the UE may transmit another random access message via the resources allocated for the random access message.