NR-U Control Information Blocks for Faster PDCCH Detection
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Solution Overview
Problem
The NR-U system lacks clear regulations for designing control information indication, leading to inefficiencies in blind detection times of the PDCCH, particularly on unlicensed spectra where communication devices must follow Listen Before Talk (LBT) principles.
Innovation Solution
A method for transmitting downlink control information (DCI) that includes information blocks containing cell identifiers, SFI, frequency domain resource indications, COT length, and other parameters, allowing terminal devices to determine valid control information and resource allocations dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device performs blind detection of PDCCH on unlicensed spectrum following LBT principles, then the device can detect control information when the channel is idle, but the detection time increases and detection efficiency decreases due to channel busy conditions
Solution Approach 1:
The network device performs channel sensing and obtains channel access opportunity before transmitting DCI, and pre-configures the terminal device with time-frequency resource information for SSB transmission. This preliminary action ensures that the terminal device can directly receive control information on pre-configured resources without performing blind detection, thereby reducing detection time while maintaining reliable control information delivery
2Loss of information
If the network device transmits DCI with detailed control information on unlicensed spectrum, then the control information completeness improves, but the signaling overhead increases and transmission efficiency decreases
Solution Approach 1:
The DCI is segmented into two parts: part 1 contains essential control information (time-frequency resource allocation for SSB, basic scheduling parameters) transmitted on unlicensed spectrum, while part 2 contains supplementary control information that can be transmitted separately or on licensed spectrum. This segmentation reduces the signaling overhead on unlicensed spectrum while ensuring complete control information delivery
Solution Approach 2:
The patent introduces an intermediary mechanism where the network device first transmits part 1 of DCI on unlicensed spectrum, and the terminal device uses this information to determine whether to receive part 2. This intermediary approach reduces unnecessary transmission of complete DCI when channel conditions are poor, thereby reducing signaling overhead while maintaining information completeness when needed
Data Source
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AI summary
The embodiments of the present application relate to a control information transmission method, a terminal device and a network device. The method comprises: a terminal device receiving downlink control information (DCI) sent by a network device, wherein the DCI comprises at least one information block, and a first information block of the at least one information block comprises control information of a first cell; and the first information block comprises at least one of the following: an identifier of the first cell, slot format indication (SFI) information, frequency domain resource indication information, frequency domain resource, end position information of the COT, physical random access channel (PRACH) resource indication information, and position indication information of a synchronization signal block (SSB). The control information transmission method, the terminal device and the network device in the embodiments of the present application can effectively realize the indication of control information in an NR-U system.