Short Subframe Random Access for Millisecond Latency
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Solution Overview
Problem
Current LTE systems experience excessively long transmission delays during the random access procedure, which cannot meet the short-delay requirements of services like the Internet of Vehicles and smart grids, where delays need to be as short as 1 millisecond.
Innovation Solution
Implementing a random access method that involves the user equipment sending a random access request message carrying short subframe service information, allowing the UE and base station to exchange subsequent messages over a resource corresponding to a short subframe service, with the duration of the short subframe being less than 1 millisecond, thereby reducing the overall delay of the random access procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LTE random access procedure uses standard subframe duration of 1 millisecond, then the system maintains compatibility with existing LTE architecture, but the transmission delay becomes excessively long (approximately 50 milliseconds) and cannot meet short-delay service requirements
Solution Approach 1:
The patent divides the subframe into two types: standard subframes (1 millisecond duration) and short subframes (less than 1 millisecond duration). This segmentation allows the system to maintain compatibility with existing LTE architecture using standard subframes while introducing short subframes specifically for short-delay services, thereby resolving the contradiction between architectural compatibility and delay reduction
Solution Approach 2:
The patent introduces dynamic subframe configuration where the base station can flexibly configure the duration of subframes based on service requirements. The system can dynamically switch between standard and short subframe durations, allowing the random access procedure to adapt to different service delay requirements while maintaining overall system compatibility
2Adaptability or versatility
If the system uses standard 1 millisecond subframe duration for random access procedure, then the existing LTE architecture is maintained, but the delay requirement of 1 millisecond for Internet of Vehicles and smart grid services cannot be met
Solution Approach 1:
The patent applies different subframe durations to different service types: standard 1 millisecond subframes are used for normal services requiring compatibility, while short subframes with duration less than 1 millisecond are specifically allocated for short-delay services such as Internet of Vehicles and smart grid applications. This local differentiation allows the system to meet diverse service requirements without compromising overall compatibility
Solution Approach 2:
The patent creates a universal subframe structure that can serve multiple functions: standard subframes handle常规 services and maintain LTE compatibility, while short subframes handle urgent short-delay services. The base station can dynamically allocate and switch between these subframe types, making the system universally adaptable to different service requirements
Data Source
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AI summary
Embodiments of the present invention disclose a random access method, user equipment, and a base station. User equipment sends, to a base station, a random access request message carrying short subframe service information, where the short subframe service information indicates that the UE is to perform a short subframe service after a random access procedure is triggered, and duration of a short subframe is less than 1 millisecond. After transmission of the random access request message is complete, the user equipment and the base station exchange rest messages of the random access procedure over a resource corresponding to the short subframe service. Design of a shorter random access procedure reduces a delay for UE to enter an active state from an idle state, so as to reduce a time required for an entire random access procedure. A delay requirement of a short-delay service is met.