Random Access Method Reducing Latency via Merged Signaling
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Solution Overview
Problem
Existing random access procedures in wireless communication systems suffer from high latency due to multiple signaling exchanges between terminal devices and network devices, making them unsuitable for applications requiring low latency.
Innovation Solution
A method where a terminal device receives information about a PRACH resource set and associated PUSCH resources, and sends a preamble sequence and uplink data on valid resources, while skipping uplink data transmission when all associated PUSCH resources are invalid, thereby improving resource utilization and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional multi-step RACH procedures are used, then signaling exchange is completed, but latency is high
Solution Approach 1:
The patent combines the random access preamble transmission and uplink data transmission into a single MsgA message, and merges the random access response and conflict resolution into a single MsgB message. This consolidation reduces the number of signaling steps from four separate messages in traditional procedures to just two messages, directly addressing the latency issue while maintaining necessary signaling functions.
Solution Approach 2:
The patent enables the terminal to pre-validate PRACH and PUSCH resources before initiating the random access procedure. By performing validity checks on time domain resources and frequency domain resources in advance, the terminal可以避免 transmitting on invalid resources, reducing unnecessary signaling exchanges and lowering access latency.
2Ease of operation
If PRACH and PUSCH resources are preconfigured, then resource allocation is simplified, but resource validity becomes an issue
Solution Approach 1:
The patent implements a pre-validation mechanism where the terminal checks whether configured PRACH resources fall within valid time domain windows and whether PUSCH resources are properly allocated before use. This preliminary validation ensures that preconfigured resources are reliable and valid, resolving the contradiction between simplified configuration and resource reliability.
Solution Approach 2:
The patent incorporates feedback mechanisms where the network device provides validity information about PRACH and PUSCH resources to the terminal. The terminal uses this feedback to determine whether to proceed with transmission on configured resources, ensuring reliability while maintaining the simplicity of preconfiguration.
3Reliability
If terminal validates all resources before transmission, then transmission reliability improves, but access latency increases
Solution Approach 1:
The patent performs resource validation in advance, during the configuration phase or before the random access procedure is initiated. By completing validity checks beforehand rather than during the actual access procedure, the patent ensures transmission reliability while minimizing the time impact on random access latency.
4Reliability
If all PUSCH resources are validated, then uplink data transmission reliability improves, but resource utilization decreases when resources are invalid
Solution Approach 1:
The patent validates only the necessary PUSCH resources associated with valid PRACH resources. Rather than validating all possible resources, the terminal performs validation on a selective basis - only checking PUSCH resources that are actually needed for the current random access attempt. This partial validation approach maintains transmission reliability while improving resource utilization by avoiding unnecessary validation overhead.
Data Source
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AI summary
Embodiments of this application provide a random access method, an apparatus, and a system, to reduce a latency in random access and improve resource utilization. A terminal device receives, from a network device, information about a PRACH resource set and information about one or more PUSCH resources associated with each PRACH resource in the PRACH resource set. If a first PUSCH resource associated with a valid first PRACH resource in the PRACH resource set is valid, the terminal device sends a first preamble sequence to the network device on the first PRACH resource, and sends uplink data to the network device on the first PUSCH resource. The network device receives the first preamble sequence from the terminal device on the first PRACH resource, and receives the uplink data from the terminal device on the first PUSCH resource. The first preamble sequence is a preamble sequence in a preamble sequence set associated with the first PUSCH resource.