Radio Station TTI Segmentation for Legacy Compatibility
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Solution Overview
Problem
The existing B4G TDD system lacks backward compatibility with LTE and LTE-Advanced systems, leading to reduced radio resource utilization efficiency due to differences in subframe structures, which complicates communication with legacy UEs and results in increased access latency and resource wastage.
Innovation Solution
Implementing a radio communication system that supports both legacy and non-legacy UEs by using multiple transmission time intervals (TTIs), where legacy UEs operate with a 1 ms TTI and non-legacy UEs use a shorter 0.5 ms TTI, allowing for efficient allocation and utilization of time-frequency resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single subframe structure is used for all UEs, then system complexity is reduced, but compatibility with both legacy and non-legacy UEs cannot be achieved
Solution Approach 1:
The subframe is segmented into multiple transmission time intervals (TTIs) with different durations. Specifically, one subframe contains both a first TTI (equal to subframe duration, 1ms) for legacy UEs and a second TTI (shorter than subframe duration, e.g., 0.5ms) for non-legacy UEs. This segmentation allows different UE types to operate with their respective TTI requirements within the same subframe structure, achieving multi-UE compatibility without requiring separate subframe designs.
Solution Approach 2:
The patent introduces a temporal dimension by allowing multiple TTIs with different durations to coexist within a single subframe time interval. Instead of choosing between different subframe structures, the system layers multiple TTI durations in the time dimension within the same subframe, enabling legacy UEs (1ms TTI) and non-legacy UEs (shorter TTI) to operate simultaneously without increasing overall system structural complexity.
2Adaptability or versatility
If multiple TTIs with different durations are used, then compatibility with both legacy and non-legacy UEs is achieved, but radio resource utilization efficiency deteriorates
Solution Approach 1:
Different portions of the subframe are allocated with different TTI characteristics tailored to specific UE types. The first TTI region is optimized for legacy UEs with 1ms duration, while the second TTI region uses shorter duration for non-legacy UEs. This local differentiation allows each UE type to operate with its optimal TTI configuration without forcing a one-size-fits-all approach, thereby improving overall resource utilization efficiency while maintaining compatibility.
3Loss of time
If a shorter TTI is used for non-legacy UEs, then access latency is reduced, but resource allocation complexity increases
Solution Approach 1:
The resource allocation mechanisms for both legacy and non-legacy UEs are merged into a unified framework within the subframe structure. The base station allocates resources for multiple TTIs (both 1ms and shorter duration) using a single resource allocation process, rather than maintaining separate allocation procedures. This merging reduces the complexity of resource allocation while enabling non-legacy UEs to benefit from shorter TTIs and reduced access latency.
Data Source
AI summary
A radio station (3) is configured to perform, with at least one radio terminal (1, 2), first radio communication in accordance with a first transmission time interval (TTI) and second radio communication in accordance with a second TTI. The first TTI is equal to a duration of one subframe (410, 510). The second TTI is shorter than the duration of the subframe (410, 510). The radio station (3) is configured to receive assistance information (802, 904) regarding the second radio communication from the radio terminal (2) capable of performing the second radio communication or from a higher network node (4).