Enhanced PUCCH Interlace Design for Unlicensed Spectrum
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Solution Overview
Problem
Legacy LTE systems face challenges in efficient uplink control signaling in unlicensed spectrum, particularly due to long PUCCH transmission durations that can block other incumbents from accessing the system, and require innovative designs for reliable feedback transmission with reduced latency and interference.
Innovation Solution
The introduction of short and long enhanced PUCCH designs, along with alternative SRS transmission options, utilizing B-IFDMA and interlaced resource allocation to minimize transmission duration and interference, allowing for efficient UCI transmission and channel estimation while adhering to unlicensed spectrum regulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long PUCCH transmission duration is used, then reliable feedback transmission is achieved, but other incumbents are blocked from accessing the system
Solution Approach 1:
The patent segments the PUCCH transmission into two distinct formats: short PUCCH (sPUCCH) occupying 1-4 symbols and long PUCCH (ePUCCH) occupying 5-14 symbols. This segmentation allows the system to choose appropriate transmission durations based on channel conditions and traffic requirements, thereby reducing unnecessary long transmissions that block other incumbents while maintaining reliable feedback transmission when needed.
2Productivity
If short PUCCH transmission duration is used, then system access efficiency is improved, but feedback transmission reliability may be compromised
Solution Approach 1:
The patent implements dynamic PUCCH format selection where the UE and eNB can adaptively choose between short and long PUCCH formats based on real-time channel conditions, traffic type, and quality requirements. This dynamic adaptation ensures that short PUCCH is used for efficient access when conditions permit, while long PUCCH is activated when reliability is paramount, thus resolving the contradiction between efficiency and reliability.
3Object-affected harmful factors
If interlaced resource allocation is used, then interference is reduced, but resource allocation complexity increases
Solution Approach 1:
The patent applies interlaced resource allocation where PUCCH resources are segmented into multiple interleaved resource blocks distributed across the frequency domain. This segmentation approach reduces localized interference by spreading PUCCH transmissions across different frequency resources, while the standardized interleaving patterns keep the allocation complexity manageable through systematic resource mapping rules.
Data Source
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AI summary
Techniques for communicating UCI (Uplink Control Information) in unlicensed band systems are discussed. One example embodiment comprises a memory; and one or more processors configured to: generate an ePUCCH (enhanced Physical Uplink Control Channel) in a subframe via a first interlace of an unlicensed frequency band, wherein the first interlace comprises a plurality of non-contiguous RBs (Resource Blocks) equally spaced in a frequency domain; generate a UCI message for the unlicensed frequency band, wherein the UCI message comprises one or more of HARQ (Hybrid Automatic Repeat Request) ACK (Acknowledgement) feedback, CSI (Channel State Information), or a SR (Scheduling Request); and map the UCI message to the first interlace for the ePUCCH.