DMRS Port Group Segmentation for MIMO Interference Cancellation
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Solution Overview
Problem
In MIMO communication systems, inter-layer interference between different data flows sent through DMRS port groups is severe due to the inability to perform joint precoding, and existing methods struggle to independently decode data flows mapped to different transport layers, hindering interference cancellation.
Innovation Solution
A data communication method where a network device determines DMRS port groups and communicates data by dividing a transport block into code block groups, each corresponding to a DMRS port group, allowing independent decoding and supporting interference cancellation by mapping data flows to distinct transport layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple DMRS port groups are used for MIMO communication, then system channel capacity is increased, but inter-layer interference between different data flows becomes severe
Solution Approach 1:
The transport block is segmented into multiple code block groups (CBGs), where each CBG is independently coded and mapped to a specific DMRS port group. This segmentation allows the terminal to independently decode each CBG corresponding to different DMRS port groups, enabling interference cancellation between layers while maintaining high system channel capacity through multi-port MIMO communication.
2Reliability
If joint precoding is performed on DMRS ports in the same group, then communication quality is improved, but independent decoding of data flows mapped to different transport layers cannot be achieved
Solution Approach 1:
The code block group (CBG) is introduced as an intermediate segmentation unit between the transport block and individual DMRS ports. Each CBG is independently coded and mapped to specific DMRS ports within a port group, allowing joint precoding within the port group while maintaining independent decoding capability across different port groups through the CBG boundary.
Solution Approach 2:
Different CBGs are mapped to different DMRS port groups with distinct quasi-co-location (QCL) relationships. This local differentiation allows joint precoding to be applied locally within each port group for improved communication quality, while the global separation through CBG mapping enables independent decoding across different port groups.
3Object-affected harmful factors
If interference cancellation receiver is deployed, then inter-layer interference is reduced, but the precondition of independent decoding for data flows mapped to different transport layers must be satisfied
Solution Approach 1:
The transport block is divided into multiple independently coded CBGs, each mapped to specific DMRS port groups. This segmentation structure provides the independent decoding capability required by interference cancellation receivers, as each CBG can be decoded separately using its corresponding DMRS ports, thereby enabling interference cancellation without increasing device complexity.
Data Source
Figure 1~2A
Figure 2B
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AI summary
Embodiments of this application provide a data transmission method, a network device, and a terminal device. The method includes: determining, by a network device, demodulation reference signal DMRS port groups, where a quantity of the DMRS port groups is greater than or equal to 2; and further, communicating, by the network device, data with a terminal device, where the data is corresponding to a transport block, the transport block is divided into at least one code block group CBG, and each of the at least one CBG is corresponding to one DMRS port group and is mapped to a transport layer corresponding to the one DMRS port group. It can be learned that, it is ensured that data flows sent through different DMRS port groups belong to different CBGs, so that the terminal device can independently decode a CBG corresponding to each DMRS port group, and therefore can support interference cancellation performed by an interference cancellation receiver.