DMRS Configuration Overhead Reduction via Grouped Port Indication
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Solution Overview
Problem
Current DMRS configuration methods in LTE result in a large overhead for network devices to indicate reference signal configurations to terminal devices, especially with increasing numbers of orthogonal DMRS ports, and do not consider multi-user scheduling and retransmission requirements effectively.
Innovation Solution
The method involves dividing reference signal ports into groups and transmitting an indication of selected groups to terminal devices, allowing for reduced payload size in Downlink Control Information and flexible multi-user scheduling and retransmission with the same layers for one codeword, thereby reducing overhead and enhancing configuration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of orthogonal DMRS ports is increased to support more users and layers, then the system capacity and multi-user scheduling flexibility are improved, but the overhead for indicating DMRS configuration to terminal devices increases significantly
Solution Approach 1:
The patent segments the DMRS configuration indication into two parts: (1) a first indication message that provides terminal devices with a set of candidate DMRS configurations, and (2) a second indication message that selects specific configurations from the candidate set. This segmentation allows the network to pre-establish multiple configuration options without transmitting all details continuously, thereby supporting flexible multi-user scheduling while reducing the overhead of configuration indication.
2Manufacturing precision
If detailed DMRS configuration information is transmitted to each terminal device, then the configuration precision and transmission accuracy are improved, but the payload size of Downlink Control Information increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring a set of candidate DMRS configurations and transmitting them to terminal devices in advance via a first indication message. When actual DMRS transmission is needed, the network only needs to send a second indication message selecting from the pre-configured candidates. This preliminary configuration approach maintains high configuration precision while significantly reducing the payload size of control information during active transmission.
3Adaptability or versatility
If separate DMRS configurations are provided for each user, then the multi-user scheduling capability is improved, but the complexity of configuration management and signaling overhead increase
Solution Approach 1:
The patent implements universality by creating a shared pool of candidate DMRS configurations that can be reused across multiple terminal devices. The first indication message establishes a universal configuration set that serves multiple users, and the second indication message selectively assigns specific configurations from this universal set to different users. This approach enables multi-user scheduling capability while reducing configuration management complexity through configuration reuse.
Data Source
AI summary
A terminal includes a processor configured to: receive, from a network device, an indication indicating the maximum number of codeword(s); receive, from the network device, a Downlink Control Information (DCI) indicating only one set of Modulation and Coding Scheme (MCS), New Data Indication (NDI), and Redundancy Version (RV) if the indication indicating the maximum number of codeword(s)is 1; determine a configuration of MCS, NDI, and RV for downlink transmission based on the DCI; and determine a bit number of the DCI for an index value associated with a configuration of DeModulation Reference Signal (DMRS) based a parameter related with a number of symbols for the DMRS.