Multiple PRACH Preamble Transmission to Reduce RACH Collisions
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Solution Overview
Problem
In wireless communication networks, physical random access channel (PRACH) collisions occur when multiple user equipments (UEs) select the same PRACH resource and preamble, leading to transmission failures and increased latency in accessing the network.
Innovation Solution
A user equipment (UE) transmits multiple PRACH preambles in the same PRACH repetition cycle or configuration period, reducing the likelihood of collisions by using different preambles for each transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple UEs use the same PRACH resource and preamble for network access, then the network access process is simple and fast, but PRACH collisions occur leading to transmission failures and increased latency
Solution Approach 1:
The patent segments the PRACH preamble transmission process into multiple separate transmissions, where each transmission uses a different preamble from a set of multiple preambles. This segmentation divides the single access attempt into multiple independent attempts, reducing collision probability while maintaining simplicity through standardized transmission procedures.
Solution Approach 2:
The patent applies partial action by transmitting only a subset of multiple preambles (at least one, potentially multiple) rather than all possible preambles. This allows the UE to reduce collision risks through multiple attempts without the excessive complexity of exhaustively trying every possible preamble combination.
2Reliability
If a UE transmits multiple PRACH preambles in the same PRACH repetition cycle, then the likelihood of collisions is reduced, but the transmission time and processing complexity increase
Solution Approach 1:
The patent utilizes periodic action by transmitting multiple preambles within the same PRACH repetition cycle or configuration period. This periodic structure allows multiple preamble transmissions to occur in a structured time pattern, reducing latency compared to sequential cycles while maintaining collision avoidance through preamble diversity.
Solution Approach 2:
The patent applies preliminary action by preparing and selecting multiple preambles in advance before the random access procedure begins. The UE receives system information indicating multiple preambles and selects from these pre-prepared options, reducing the time needed during actual transmission attempts and minimizing overall access latency.
3Measurement precision
If the network node transmits multiple timing advances in the response message, then the accuracy of uplink timing is improved, but the response message complexity and processing overhead increase
Solution Approach 1:
The patent segments the timing advance information into separate entries, with each timing advance associated with a specific preamble transmission. This segmentation allows the network node to provide precise timing information for each individual preamble attempt, improving uplink timing accuracy while keeping the response message structure manageable through organized, discrete timing advance entries.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive system information associated with a network node, the system information indicating multiple physical random access channel (PRACH) preambles to use for a random access channel (RACH) procedure with the network node. The UE may transmit, as part of the RACH procedure with the network node, a first transmission comprising a first PRACH preamble of the multiple PRACH preambles and a second transmission comprising a second PRACH preamble of the multiple PRACH preambles. Numerous other aspects are described.