FDM Guard Interval Adaptation for Varying Delay Spreads
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Solution Overview
Problem
Current wireless communication systems, particularly 5G NR, face challenges in efficiently managing guard intervals (GI) for different user equipment (UEs) due to varying delay spreads, which affects data multiplexing and waveform generation, leading to suboptimal performance and adaptability.
Innovation Solution
A method where a base station calculates and multiplexes guard intervals for each UE based on its delay spread, allowing for different GI sequences or lengths to be used for frequency domain multiplexing, enabling adaptable and efficient waveform generation without changing the DFT size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single guard interval configuration is used for all UEs, then system complexity is reduced, but performance and reliability deteriorate due to varying delay spreads
Solution Approach 1:
The patent applies local quality by configuring different guard interval parameters (length, type, sequence) for different UEs based on their individual delay spread characteristics. Each UE receives a customized GI configuration from the network side, allowing the system to optimize performance for each user's specific channel conditions rather than using a uniform configuration for all users.
Solution Approach 2:
The patent implements dynamics by enabling the guard interval configuration to be adaptively adjusted for different UEs and different transmission scenarios. The network side can dynamically select and configure appropriate GI parameters based on real-time channel conditions, UE capabilities, and service requirements, making the system flexible and adaptive rather than static and rigid.
2Adaptability or versatility
If different guard interval sequences are used for different UEs, then adaptability and performance are improved, but system complexity increases
Solution Approach 1:
The patent applies parameter changes by varying multiple guard interval parameters including length (short/long), type (cyclic/zero-padding), and sequence (different reference signals) to achieve diverse and optimized GI configurations for different UEs. This multi-parameter approach enables fine-grained adaptation to various channel conditions and service requirements.
Solution Approach 2:
The patent implements universality by designing a unified guard interval configuration mechanism that can serve multiple purposes: it provides inter-UE multiplexing through different GI sequences, maintains backward compatibility with existing systems, supports various service types (eMBB, URLLC, mMTC), and works across different frequency ranges. The same GI configuration framework achieves multiple functions simultaneously.
3Reliability
If guard interval is extended to accommodate larger delay spread, then coverage and reliability are improved, but spectral efficiency decreases
Solution Approach 1:
The patent applies local quality by matching the guard interval length to each UE's specific delay spread characteristics rather than using a uniformly extended GI for all users. UEs with smaller delay spreads receive shorter GIs, maintaining spectral efficiency, while only UEs with larger delay spreads receive extended GIs to ensure their signal reliability. This localized optimization balances coverage and efficiency.
Solution Approach 2:
The patent implements partial action by applying extended guard intervals only where necessary - specifically for UEs experiencing large delay spreads or operating in challenging environments. Not all UEs receive extended GIs; the network side selectively applies GI extension based on measured channel conditions, avoiding unnecessary overhead for users who don't require it, thus maintaining overall spectral efficiency while ensuring reliability where needed.
Data Source
AI summary
Method and apparatus to use different GI sequences for different FDM UEs. The apparatus calculates a GI of each UE from a set of UEs based at least on a delay spread associated with each UE from the set of UEs. The apparatus multiplexes data and the GI of each respective UE from the set of UEs to generate a waveform. The apparatus transmits the waveform to the set of UEs. The apparatus may receive, from each UE from the set of UEs, the delay spread associated with each UE from the set of UEs. The apparatus may multiplex the GI of each respective UE from the set of UEs prior to performing a DFT operation on the GI and the data. The apparatus may multiplex the GI of each respective UE from the set of UEs after performing an IDFT operation to generate the waveform.