Downlink Control Information Segmentation for Signaling Overhead
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Solution Overview
Problem
The increasing number of Downlink Control Information (DCI) formats in LTE systems leads to tedious testing and implementation challenges for radio access networks and user equipment, resulting in inefficient control signaling on the downlink control channel, as only a small portion of the DCI changes with each transmission.
Innovation Solution
A method is introduced where a first control element with a set of transmission parameters is sent, followed by a second control element containing only the changed parameters, allowing for reduced overhead and efficient signaling by communicating based on the updated subset of parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed-size DCI formats are used for every radio transmission assignment, then backward compatibility is maintained, but control signaling overhead increases significantly
Solution Approach 1:
The DCI message is segmented into two parts: a common part containing fields that remain unchanged across transmissions, and a dynamic part containing only the fields that change. This segmentation allows the system to maintain backward compatibility through the common part while reducing overhead by transmitting only changes in the dynamic part.
Solution Approach 2:
The invention extracts and separates the changing fields from the complete DCI message. By taking out only the dynamic fields that need to be updated and transmitting them separately, the system reduces the amount of data that needs to be transmitted while maintaining full functionality.
2Adaptability or versatility
If the number of DCI formats is increased to support new transmission modes, then system versatility improves, but implementation complexity and testing burden increase
Solution Approach 1:
The common part of the DCI message serves multiple functions across different transmission modes and DCI formats. By maintaining a universal structure for common fields, the system can support multiple transmission modes without requiring separate complete DCI formats for each mode, thereby reducing implementation complexity.
Solution Approach 2:
The invention introduces dynamic fields that can be selectively activated or deactivated depending on the transmission mode and configuration. This dynamic approach allows the system to adapt to different transmission modes without requiring static, pre-defined DCI formats for each mode, reducing the overall number of formats needed.
3Loss of information
If complete DCI messages are transmitted for every assignment, then information completeness is ensured, but channel capacity is wasted on redundant information
Solution Approach 1:
The invention extracts only the changing fields from the complete DCI message and transmits them separately. The UE combines these extracted dynamic fields with the common fields (either from previous transmissions or from a common pool) to reconstruct the complete DCI information, ensuring information completeness while reducing channel capacity usage.
Solution Approach 2:
The common fields are prepared and made available in advance (either stored at the UE or maintained in a common pool), so that when a DCI transmission occurs, only the dynamic fields need to be transmitted. This preliminary preparation eliminates the need to retransmit unchanged information, reducing redundant channel usage.
Data Source
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AI summary
A technique for signaling downlink control information from a base station (106) to a user equipment (104) is described. As to a method aspect of the technique, a first control element including first DCI (702) is sent to the user equipment (104). The first DCI (702) includes values specifying a set (710) of transmission parameters. A second control element including second DCI (704) is sent to the UE (104). The second DCI (704) includes values specifying a subset (712) of the set (710). The base station (106) and the user equipment (104) communicate according to the set (710) of transmission parameters, wherein the values included in the first DCI (702) specify the transmission parameters (714) not in the subset (712), and wherein the values included in the second DCI (704) specify the transmission parameters in the subset (712).