Dynamic Cyclic Prefix Selection for Wireless Overhead Reduction

Solution Overview

Problem

Current wireless communication systems face inefficiencies due to static cyclic prefix (CP) configurations that do not adapt to varying channel conditions, leading to increased overhead and reduced spectral efficiency.

Innovation Solution

Implementing dynamic cyclic prefix selection, where user equipment (UE) determines and communicates a second CP length based on channel quality information, allowing for adaptive CP configuration to optimize downlink communications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a static cyclic prefix configuration is used, then the system is simple to implement, but the overhead increases and spectral efficiency decreases

Engineering Contradiction:

Improveconfiguration complexityVSAvoidspectral efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent implements dynamic cyclic prefix selection where the UE determines a second CP length based on channel quality information and transmits an indication to the base station. The base station then transmits downlink signals according to the second CP configuration, allowing the system to adapt CP length to varying channel conditions rather than using a fixed static configuration.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the CP length parameter dynamically based on channel conditions. The UE measures channel quality and selects from multiple configured CP lengths (first CP configuration with first CP length, second CP configuration with second CP length) to optimize spectral efficiency while maintaining compatibility with the base station through standardized signaling mechanisms.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If a static cyclic prefix configuration is used, then the system is stable and simple, but the adaptability to different channel conditions decreases

Engineering Contradiction:

Improvesystem stabilityVSAvoidchannel condition adaptability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic cyclic prefix selection where the UE determines a second CP length based on channel quality information and transmits an indication to the base station. The base station then transmits downlink signals according to the second CP configuration, allowing the system to adapt CP length to varying channel conditions rather than using a fixed static configuration.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The UE provides feedback to the base station about channel conditions by determining and transmitting an indication of the second CP length based on measured channel quality information. This feedback loop enables the base station to adjust its downlink transmission parameters to match actual channel conditions, improving adaptability while maintaining system stability through standardized protocols.

Inventive Principle:

Principle #23Feedback

3Reliability

If a longer cyclic prefix is used to handle interference, then interference reduction improves, but the overhead increases

Engineering Contradiction:

Improveinterference resistanceVSAvoidoverhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the CP length parameter dynamically based on channel conditions. The UE measures channel quality and selects from multiple configured CP lengths (first CP configuration with first CP length, second CP configuration with second CP length) to optimize spectral efficiency while maintaining compatibility with the base station through standardized signaling mechanisms.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of always using a long CP to guarantee interference protection, the patent applies partial action by selecting CP length based on actual channel conditions. When channel quality is good, a shorter CP suffices, reducing overhead. When channel conditions deteriorate, the UE can request a longer CP configuration to provide adequate interference protection, thus avoiding excessive overhead in good conditions while maintaining reliability when needed.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11528757B2Dynamic cyclic prefix selection

Publication Date: 2022.12.13 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described for reducing overhead associated with a cyclic prefix (CP) by supporting dynamic determination of a CP length. For example, a user equipment (UE) may establish a wireless connection with a base station by receiving initial communications according to a numerology and a first CP configuration associated with a first CP length. The UE may determine a second CP length after establishing the wireless connection and may transmit an indication to the base station, indicating the second CP length. The base station may receive the indication and may transmit downlink signals according to a second CP configuration associated with the second CP length. The initial communications and the downlink signals may be associated with a same numerology or subcarrier spacing.