Dynamic Cyclic Prefix Adaptation for Wireless Resource Efficiency
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Solution Overview
Problem
Current wireless communication systems, such as LTE, often use unnecessarily long cyclic prefixes (CP) to support users with large delay spread, which degrades performance for users with smaller delay spread, leading to inefficient resource utilization and reduced data rates.
Innovation Solution
Implementing UE-specific dynamic transmission parameters, such as cyclic prefix and subcarrier spacing, based on individual radio link characteristics to optimize communication resources, allowing for variable CP and subcarrier spacing on a finer granularity, enabling flexible trade-offs between receiver complexity and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an extended (longer) cyclic prefix is used to support users with large delay spread, then robustness towards channel delay spread is improved, but transmission overhead increases and data rates decrease
Solution Approach 1:
The patent implements dynamic selection of CP duration (normal or extended) on a per-subframe basis, allowing the system to adapt to varying channel conditions. The base station determines whether to apply normal or extended CP for each subframe based on current radio link characteristics, enabling the system to switch between short and long CP durations dynamically rather than using a fixed extended CP for all subframes.
Solution Approach 2:
The patent applies different CP durations to different subframes based on local channel conditions. Instead of uniformly applying extended CP across all subframes, the system selectively applies extended CP only to subframes where large delay spread is detected, while using normal CP in subframes with acceptable delay spread, thereby optimizing performance locally for each subframe.
2Reliability
If an extended (longer) cyclic prefix is used to prevent inter-symbol and inter-carrier interference, then system performance in large delay spread channels is improved, but transmission resources are wasted for users with small delay spread
Solution Approach 1:
The system dynamically adjusts CP duration based on real-time channel conditions. The base station monitors delay spread characteristics and switches between normal and extended CP modes accordingly, ensuring that extended CP is applied only when necessary to prevent interference, thereby avoiding unnecessary resource consumption in subframes with acceptable delay spread.
Solution Approach 2:
The patent changes the CP duration parameter dynamically based on measured delay spread characteristics. The base station determines whether to use normal or extended CP by evaluating channel conditions, and adjusts the CP parameter accordingly for each subframe, optimizing the balance between interference prevention and resource efficiency.
3Stability of the object's composition
If a fixed extended cyclic prefix is used for all subframes, then all users experience consistent performance, but users with small delay spread suffer from reduced throughput
Solution Approach 1:
The patent introduces dynamic adaptation of CP duration for each subframe based on channel conditions. Instead of maintaining a fixed extended CP configuration for all subframes, the base station evaluates delay spread characteristics and selects appropriate CP duration (normal or extended) for each subframe, allowing users with small delay spread to benefit from normal CP's higher throughput while maintaining support for users with large delay spread when needed.
Solution Approach 2:
The system applies different CP durations to different subframes based on local channel conditions rather than uniformly applying extended CP. This allows the system to optimize throughput for users with small delay spread in subframes where extended CP is not required, while maintaining consistent performance support for users with large delay spread in subframes where it is needed.
Data Source
AI summary
Base station and User Equipment (UE) and methods to be performed therein for communication using a dynamic transmission parameter. The method to be performed in a base station comprises scheduling of transmission resources to a UE in an OFDM symbol associated with a dynamic parameter value. The base station is assumed to be associated with a carrier where a radio frame comprises at least one OFDM symbol associated with a fixed parameter value and at least one OFDM symbol associated with a dynamic parameter value, where the parameter is a cyclic prefix, CP, or a subcarrier spacing, Δf. The method further comprises determining a value of the parameter based on a characteristic of a radio link associated with the UE, and applying the determined value of the parameter when communicating with the UE in the scheduled transmission resources.