CSI-RS Sub-Band Selection for Intermittent Unlicensed Availability
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently processing channel state information (CSI) reference signals in the unlicensed spectrum due to sub-bands being intermittently available, leading to restrictive transmission techniques that limit the ability to transmit CSI-RS on a majority of occasions.
Innovation Solution
A method for a UE to select and process one or more sub-bands in a wideband structure of an unlicensed spectrum for CSI-RS reception, utilizing a sub-band usage indication to identify valid sub-bands and prioritize processing based on capability, priority rules, and configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If restrictive transmission techniques are used to ensure reliable CSI-RS transmission, then transmission reliability is improved, but transmission frequency and coverage are limited
Solution Approach 1:
The patent segments the unlicensed spectrum into multiple sub-bands and introduces a sub-band usage indication mechanism. Instead of treating the entire bandwidth as a single unit, the system divides it into smaller sub-bands that can be independently indicated as available or unavailable. This segmentation allows CSI-RS to be transmitted on individual valid sub-bands, increasing the frequency of transmissions while maintaining reliability through selective sub-band usage.
Solution Approach 2:
The patent implements dynamic sub-band indication where the gNB can flexibly indicate which sub-bands are currently available for CSI-RS transmission based on real-time channel conditions and LBT outcomes. This dynamic approach allows the system to adapt transmission opportunities to actual channel availability, thereby increasing transmission frequency without compromising reliability through the use of validity indicators.
2Measurement precision
If all sub-bands are processed for CSI-RS reception, then measurement precision is improved, but UE processing complexity increases
Solution Approach 1:
The patent extracts only the valid sub-bands from the entire bandwidth using the sub-band usage indication. Instead of requiring the UE to process all sub-bands, the system provides an indication that identifies which specific sub-bands contain valid CSI-RS transmissions. The UE then processes only these indicated sub-bands, reducing processing complexity while maintaining measurement precision by focusing computational resources on the relevant frequency resources.
Solution Approach 2:
The patent employs preliminary action by providing sub-band usage indications to the UE before CSI-RS reception. The UE receives advance information about which sub-bands will contain valid CSI-RS transmissions, allowing it to pre-configure its processing resources and avoid unnecessary processing of invalid sub-bands. This preliminary indication reduces UE processing complexity while ensuring that all valid sub-bands are processed for accurate CSI measurements.
3Productivity
If wideband operation is implemented to increase bandwidth utilization, then data throughput is improved, but the ability to handle intermittent sub-band availability decreases
Solution Approach 1:
The patent applies local quality by allowing different sub-bands within the wideband operation to have different validity states. Instead of treating the entire wideband as uniformly available or unavailable, the system provides granular sub-band level indications that reflect the actual availability of each sub-band. This enables wideband operation to achieve high throughput on available sub-bands while adapting to intermittent availability by selectively indicating which local sub-band portions are valid for CSI-RS transmission.
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may select one or more sub-bands, of a plurality of sub-bands in a wideband structure of an unlicensed spectrum, for processing in association with receiving a reference signal. The one or more sub-bands may include at least one valid sub-band of a set of valid sub-bands in which the reference signal is received. The user equipment may process the one or more sub-bands in association with receiving the reference signal. Numerous other aspects are provided.