Random Access Preamble Mapping for Low-Latency Uplink Access
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Solution Overview
Problem
Existing wireless communication systems face latency issues during the random access procedure, which hinder faster and more efficient network communications, particularly in 4G and 5G networks.
Innovation Solution
A method and apparatus for a random access procedure that maps a plurality of preamble indexes to a second resource, such as a physical uplink shared channel occasion, based on specific number ratios and orderings in the code, frequency, and time domains, allowing for a two-step process that eliminates the need for additional signal overhead to indicate resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional 4-step random access procedure is used, then uplink synchronization can be achieved, but latency is introduced and communication speed is reduced
Solution Approach 1:
The patent combines the random access preamble transmission with uplink data transmission into a single message (MsgA), merging the functions of message 1 and message 3 from the traditional 4-step procedure. This reduces the number of round-trip messages and eliminates access latency while maintaining uplink synchronization through the association between the preamble index and uplink timing.
Solution Approach 2:
The patent performs preliminary action by pre-associating preamble indexes with uplink timing information and resource allocations. The network device configures multiple preamble indexes where each index corresponds to specific uplink resources and timing, allowing the UE to directly determine uplink transmission parameters from the selected preamble index without waiting for separate signaling messages.
2Manufacturing precision
If additional signaling is used to allocate time/frequency resources for payload transmission, then resource allocation accuracy is improved, but signaling overhead increases and latency is added
Solution Approach 1:
The patent implements self-service by enabling the UE to autonomously determine its uplink time/frequency resources and timing parameters directly from the preamble index it selects. The preamble index implicitly carries resource allocation information, eliminating the need for explicit downlink signaling to allocate uplink resources. This reduces signaling overhead while maintaining precise resource allocation through the pre-configured mapping between preamble indexes and uplink resources.
Data Source
AI summary
A random access procedure, performed by a network device, includes selecting one of a plurality of preamble indexes of a first resource, and at least one set of the plurality of preamble indexes is mapped to at least one second resource based on a first number of the at least one set of the plurality of preamble indexes and a second number of the at least one second resource. A first message is transmitted to a network node, the first message including a preamble at the selected preamble index of the first resource and a payload in the second resource associated to the selected preamble index. A second message is received from the network node in response to a first message.