Multi-TCI Beam Feedback for mmW Reliability
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Solution Overview
Problem
Conventional wireless communication systems, particularly in millimeter wave (mmW) frequencies, face inefficiencies in data transmission due to increased signal attenuation and lack of macro diversity, leading to delays and resource wastage in feedback reports, especially when using single beamformed signals.
Innovation Solution
Implementing a method that supports acknowledgement/negative acknowledgement (ACK/NACK) feedback report design for multi-transmission configuration indicator (TCI) beam state transmissions, utilizing demodulation reference signals (DMRS) and physical uplink control channel (PUCCH) to enhance channel state information feedback and improve macro diversity across multiple beamformed channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single TCI beam state transmission is used, then device complexity is reduced, but reliability deteriorates due to lack of macro diversity and increased blockage susceptibility
Solution Approach 1:
The patent segments the transmission into multiple TCI beam states, where each beam state represents a separate transmission path. The UE receives multiple PDSCH transmissions corresponding to different TCI states and provides separate ACK/NACK feedback for each, thereby achieving macro diversity without requiring complex multi-beam simultaneous processing
Solution Approach 2:
The patent introduces a new dimension for feedback by mapping ACK/NACK bits to specific TCI states through PUCCH resource selection. Different PUCCH resources correspond to different TCI states, adding a resource dimension to the feedback mechanism that simplifies the handling of multi-beam acknowledgments
2Measurement precision
If CSI-RS/SSB reference signals are transmitted for channel monitoring, then measurement precision is improved, but loss of time increases due to delays between triggering and transmission
Solution Approach 1:
The patent performs channel state measurement using the PDSCH and DMRS that are already transmitted for data communication. By utilizing these pre-transmitted signals for measurement purposes, the system eliminates the need for separate CSI-RS/SSB triggering and transmission, thereby removing the time delay while maintaining measurement precision
Solution Approach 2:
The patent makes the PDSCH and DMRS serve dual functions: both for data transmission and for channel state measurement. This multi-functionality eliminates the need for dedicated reference signals like CSI-RS/SSB, reducing overhead and time delays while maintaining measurement capability
3Reliability
If multiple TCI beam states are transmitted for macro diversity, then reliability is improved, but loss of information increases due to inefficient feedback report resources
Solution Approach 1:
The patent adds a resource dimension to feedback by mapping different TCI state acknowledgments to different PUCCH resources. This allows efficient encoding of multi-beam feedback information by selecting appropriate resources rather than transmitting lengthy reports, thereby preventing information loss and improving feedback efficiency
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described. A user equipment (UE) may receive, during a transmission interval, a data transmission over a plurality of beamformed channels and, for each data transmission, a reference signal transmitted in conjunction with the data transmission. The UE may perform, for one or more of the plurality of beamformed channels, a channel state measurement procedure during the transmission interval using the data transmission, the reference signal, or a combination thereof. The UE may transmit, over an acknowledgement/negative acknowledgement (ACK/NACK) signal, a feedback report indicating a result of the channel state measurement procedure for the one or more of the plurality of beamformed channels. The base station may perform, based at least in part on the feedback report, subsequent transmissions to the UE over the one or more beamformed channels.