Random Access Preamble Data Multiplexing Reducing Latency
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Solution Overview
Problem
The four-step random access mechanism in current LTE protocols experiences significant time delays, which hinder the achievement of low latency and ultra-reliable communication requirements in next-generation mobile communication systems.
Innovation Solution
A method for information transmission that involves a user equipment (UE) transmitting a random access request carrying a preamble and data to an access network entity, where the preamble and data are multiplexed using techniques such as time division multiplexing (TDM) or frequency division multiplexing (FDM), and the access network entity calculates channel estimation and detects data to reduce processing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a four-step random access mechanism is used in LTE protocol, then the control plane signaling is complete and reliable, but the time delay is great and cannot meet low latency requirements
Solution Approach 1:
The patent merges the random access preamble transmission and data transmission into a single uplink message (Msg1), eliminating the need for separate Msg3 transmission. This combining of functions reduces the number of signaling steps from four to two, directly addressing the time delay issue while maintaining reliability through the integrated transmission approach.
Solution Approach 2:
The patent enables data to be transmitted in advance along with the random access preamble, rather than waiting for the completion of the four-step process. This preliminary action allows the access network entity to receive both the access request and data simultaneously, significantly reducing the overall access time while maintaining signaling reliability.
2Productivity
If random access request carries both preamble and data, then transmission efficiency is improved and time delay is reduced, but signal power allocation and interference management become more complex
Solution Approach 1:
The patent introduces specific parameter configurations for the uplink message, including subcarrier spacing, cyclic prefix length, and power allocation parameters. By defining these parameters explicitly for the combined preamble-data transmission, the system manages the complexity through standardized parameter sets while achieving improved transmission efficiency.
Solution Approach 2:
The patent segments the uplink message into distinct functional parts (preamble and data portions) with different power allocation and processing requirements. This segmentation allows the access network entity to process each part appropriately while managing overall signal complexity, balancing the benefits of combined transmission with manageable processing complexity.
3Loss of time
If preamble and data are multiplexed in the same uplink message, then the number of signaling steps is reduced from four to two, but power allocation and signal separation become more challenging
Solution Approach 1:
The patent multiplexes the preamble and data in the frequency domain using different subcarrier allocations and spacing configurations. By transitioning from time-sequential transmission (four steps) to frequency-division multiplexing within a single message, the system reduces signaling steps while providing the access network entity with dimensional separation cues for effective signal detection and processing.
Data Source
AI summary
A method for information transmission is provided by the present disclosure. The method includes: transmitting, by a first User Equipment (UE), a first random access request to an access network entity, the first random access request carrying a first preamble and data; and receiving, by the first UE, a random access response sent by the access network entity according to the first random access request.