NR Channelization with CCI and BWP for Guard Band Reduction
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Solution Overview
Problem
Existing Listen-Before-Talk (LBT) mechanisms in unlicensed spectrum access, such as LTE/LAA and MulteFire, face challenges in accurately detecting ongoing transmissions, leading to interference and unfairness among nodes, particularly when signals are weak or below noise levels, and do not efficiently utilize bandwidth due to guard bands in carrier aggregation.
Innovation Solution
The implementation of a Composite Carrier Indicator (CCI) and Bandwidth Part (BWP) management in New Radio (NR) systems to dynamically composite multiple carrier bands into a single carrier, allowing flexible carrier bandwidths and efficient spectrum utilization while ensuring fair coexistence with incumbent technologies, using LBT procedures and BWP configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LBT mechanisms are used in unlicensed spectrum access, then coexistence with incumbent technologies is ensured, but detection accuracy of ongoing transmissions deteriorates when signals are weak or below noise levels
Solution Approach 1:
The patent segments the unlicensed spectrum into multiple sub-bands and applies LBT independently to each sub-band rather than treating the entire bandwidth as a single channel. This segmentation allows for more precise detection in each sub-band, improving measurement precision while maintaining coexistence fairness through selective channel access.
Solution Approach 2:
The patent introduces reference signals as intermediary elements that facilitate accurate detection of ongoing transmissions. These reference signals serve as mediators between the LBT mechanism and the physical transmissions, enabling more reliable detection even when signals are weak or below noise levels by providing known patterns to correlate against received signals.
2Adaptability or versatility
If carrier aggregation with guard bands is used, then multiple carrier bands can be aggregated, but spectrum utilization efficiency deteriorates due to guard band losses
Solution Approach 1:
The patent extracts and removes the guard bands from the carrier aggregation structure, allowing adjacent carrier bands to be directly aggregated without the traditional protective gaps. This extraction eliminates the spectrum waste associated with guard bands while maintaining carrier aggregation capability through alternative interference management methods.
Solution Approach 2:
The patent merges adjacent carrier bands directly together without inserting guard bands between them. By combining multiple carrier bands into a continuous aggregated carrier, the patent maximizes spectrum utilization efficiency while maintaining the adaptability and versatility of carrier aggregation through proper resource allocation and interference coordination.
3Ease of operation
If fixed bandwidth carriers are used, then simple channel access is achieved, but flexible bandwidth adaptation and power management are limited
Solution Approach 1:
The patent implements dynamic bandwidth adaptation by allowing the aggregated carrier bandwidth to vary based on channel conditions, traffic demands, and power availability. The system can dynamically adjust the number and size of aggregated carrier bands, enabling flexible bandwidth adaptation while maintaining relatively simple channel access procedures through the underlying LBT mechanism applied to each sub-band.
Data Source
AI summary
Methods, systems, and apparatus designed to support flexible carrier bandwidths in new radio. Multiple carrier bands may be combined into a single composite carrier depending on channel availability in the carrier bands. A composite carrier indicator (CCI) indicates to network devices, the available carrier bands within the channel occupancy time. In addition, bandwidth part inactivity time is suspended when channel access is not available.