Terminal NACK-Only Feedback for Multiple G-RNTI Scrambling
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Solution Overview
Problem
In the context of 5G New Radio (NR) and Beyond 5G communication systems, the challenge arises when multiple network identifiers are configured for scrambling the downlink channel, leading to difficulties in properly executing NACK-only feedback for Multicast and Broadcast Services (MBS), as the system struggles to determine which PDSCH has been received by the UE, resulting in improper feedback transmission.
Innovation Solution
The implementation of specific operations in the terminal and radio communication method, where the UE controls the transmission of feedback using PUCCH resources associated with each network identifier, allowing for proper NACK-only feedback even when multiple G-RNTIs are set, by defining distinct PUCCH resources and HARQ-ACK codebooks for each G-RNTI, ensuring unified feedback sequences and avoiding complications in feedback transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple network identifiers (G-RNTIs) are configured for scrambling the downlink channel, then the system can support multiple multicast/broadcast services, but the terminal cannot properly determine which PDSCH has been received, leading to improper feedback transmission
Solution Approach 1:
The patent segments the feedback transmission by associating each G-RNTI with a distinct PUCCH resource and HARQ-ACK codebook. This segmentation allows the terminal to properly identify and feedback reception status for each specific multicast/broadcast service independently, resolving the ambiguity caused by multiple network identifiers.
2Productivity
If NACK-only feedback scheme is used to reduce feedback overhead, then the feedback transmission efficiency is improved, but the system cannot properly handle multiple G-RNTIs as the terminal cannot determine which PDSCH has been received
Solution Approach 1:
The patent introduces PUCCH resources and HARQ-ACK codebooks as intermediary elements that mediate between the terminal and the network for feedback transmission. Each G-RNTI is associated with specific PUCCH resources and HARQ-ACK codebooks, serving as intermediaries that enable the terminal to properly determine and transmit feedback for each service while maintaining the efficient NACK-only scheme.
3Adaptability or versatility
If multiple G-RNTIs are configured for different multicast services, then service diversity is enhanced, but the terminal faces difficulty in executing proper NACK-only feedback due to inability to identify received PDSCH
Solution Approach 1:
The patent segments the feedback identification information by creating distinct PUCCH resources and HARQ-ACK codebooks for each G-RNTI. This segmentation preserves the service diversity enabled by multiple G-RNTIs while preventing information loss by ensuring the terminal can properly identify which PDSCH has been received for each specific service.
Data Source
AI summary
A terminal comprises: a reception unit that receives data via a downlink channel in a data delivery for a plurality of terminals; a transmission unit that transmits a feedback on the data in a scheme transmitting a negative response without transmitting an affirmative response; and a control unit that controls the transmission of the feedback in a specific operation when two or more network identifiers for scrambling the downlink channel are configured.