Downlink Control Information Bit Length Determination for 5G URLLC
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Solution Overview
Problem
Current methods for control information transmission in 5G wireless communications, particularly for URLLC services, face inefficiencies due to bit length redundancy in downlink control information, leading to increased complexity and reduced transmission efficiency at the air interface.
Innovation Solution
A method where a terminal device determines the bit length of downlink control information (DCI) based on the location of a target time unit within a second time unit, using time domain resource location information to indicate the length or start location of a third time unit, thereby avoiding blind detection of different bit lengths and reducing redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If control information uses variable bit length to indicate time domain resource location, then flexibility in indicating different time domain lengths and start locations is improved, but bit length redundancy increases and transmission efficiency decreases
Solution Approach 1:
The time domain resource location information is segmented into two parts: a first part indicating time domain length information and a second part indicating time domain start location information. This segmentation allows each part to be optimized independently, reducing overall bit redundancy while maintaining flexibility in indicating different time domain configurations.
Solution Approach 2:
Different bit allocation strategies are applied to different parts of the time domain resource location information. The first part (time domain length) and second part (start location) use different coding schemes appropriate to their specific requirements, optimizing the bit efficiency for each local component while maintaining overall flexibility.
2Adaptability or versatility
If control information uses variable bit length to indicate time domain resource location, then flexibility in indicating different time domain lengths and start locations is improved, but complexity of the receiver increases
Solution Approach 1:
By segmenting the time domain resource location information into distinct first and second parts with clear functional boundaries, the receiver's decoding process is simplified. Each part can be processed independently according to its specific coding rules, reducing the overall computational complexity compared to processing a single variable-length field.
Solution Approach 2:
The invention changes the parameter structure from a single variable-length field to two separate fields with defined relationships. This parameter transformation allows the receiver to use more straightforward decoding logic based on the explicit bit allocation rules, reducing complexity while maintaining the ability to indicate various time domain configurations.
3Loss of time
If a shorter time scheduling unit is used to meet URLLC latency requirements, then transmission latency is reduced, but bit length redundancy of control information increases
Solution Approach 1:
The control information for shorter time scheduling units is segmented into specialized first and second parts that efficiently encode the reduced time domain parameters. This segmentation eliminates the need for redundant bits that would be required in a unified variable-length scheme, achieving compact representation despite the increased scheduling flexibility needed for low-latency URLLC transmissions.
Data Source
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AI summary
This application provides a control information transmission method, a terminal device, and a network device. The method includes: determining, by a terminal device, a bit length of downlink control information DCI based on a location of a target first time unit in a second time unit, where the DCI includes time domain resource location information, the time domain resource location information is used to indicate at least one of time domain length information of a third time unit and time domain start location information for data transmission scheduled based on the DCI, the DCI is carried in the target first time unit, and a time domain length of the third time unit is less than or equal to a time domain length of the second time unit; and receiving, by the terminal device, the DCI from a network device. The control information transmission method in the embodiments of this application helps to reduce bit redundancy of the downlink control information DCI, prevents the terminal device from performing blind detection on downlink control information of different bit lengths, and reduces complexity of a receiver.