CSI-RS Mapping for Extended Antenna Ports in FD-MIMO
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Solution Overview
Problem
The existing 3GPP standard CSI-RS configurations support up to eight antenna ports, which is insufficient for implementing channel quality measurement in FD-MIMO systems with extended numbers of antenna ports, such as 16, 32, and 64.
Innovation Solution
The CSI-RS configurations are extended to support a larger number of antenna ports by defining new mappings, combining existing mappings, or switching mappings within subframes or resource blocks, ensuring proximity in time and frequency allocation to minimize channel variation and reduce overhead, while maintaining compatibility with legacy systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of antenna ports is extended beyond 8 for FD-MIMO systems, then system performance and frequency utilization efficiency are improved, but the existing CSI-RS configuration standards become insufficient and cannot support the extended antenna ports
Solution Approach 1:
The patent segments the CSI-RS configuration into multiple parameter sets (resource element offsets, resource block offsets, subframe configurations) that can be independently configured for different antenna port groups. This allows the system to support extended antenna ports beyond 8 by dividing them into multiple groups, each with its own configuration parameters, thereby resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The patent extends the CSI-RS configuration from a two-dimensional structure (frequency and time) to a three-dimensional structure by adding the antenna port dimension. It introduces new configuration parameters that operate in the antenna port domain, allowing systematic support for extended antenna ports while maintaining compatibility with existing two-dimensional resource allocation structures.
2Adaptability or versatility
If new CSI-RS mappings are defined for extended antenna ports, then compatibility with legacy systems is reduced, but support for FD-MIMO is achieved
Solution Approach 1:
The patent designs the CSI-RS configuration parameters to serve multiple functions: they can configure CSI-RS for both legacy 8-port systems and extended FD-MIMO systems with more antenna ports. The same configuration parameters (resource element offsets, resource block offsets, subframe configurations) are used universally across different system types, ensuring backward compatibility while enabling forward adaptability.
Solution Approach 2:
The patent introduces dynamic configuration mechanisms where the CSI-RS parameters can be adjusted based on the number of antenna ports. The system can dynamically select appropriate configuration values from predefined sets or calculate them based on the actual number of antenna ports, allowing seamless transition between legacy and extended configurations without compromising compatibility.
3Measurement precision
If CSI-RS is transmitted with frequent transmission periods for accurate channel quality measurement, then measurement precision is improved, but overhead increases
Solution Approach 1:
The patent introduces configurable parameters that control the transmission periodicity and resource allocation of CSI-RS. By adjusting these parameters (resource element offsets, resource block offsets, subframe configurations), the system can optimize the balance between measurement precision and overhead. The parameters allow flexible adaptation of CSI-RS density based on channel conditions and system requirements.
Solution Approach 2:
The patent applies different CSI-RS configuration parameters to different antenna port groups and different time-frequency resources. Instead of using a uniform high-density configuration across all resources, the system applies localized optimization where higher density is used only where needed for accurate measurement, reducing overall overhead while maintaining measurement precision where critical.
Data Source
Figure 1(A)~1(C)
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AI summary
A base station that communicates with a mobile station by using a plurality of antenna ports includes a mapping information communication unit configured to generate mapping of reference signals for measuring channel state information of the antenna ports by combining, within a resource block, mappings of reference signals for measuring the channel state information, the mappings being defined for a predetermined number or less of the antenna ports, and configured to communicate information indicating the generated mapping to the mobile station; a multiplexer configured to multiplex the reference signals for measuring the channel state information in one or more resource elements in the resource block in accordance with the generated mapping; and a transmitter configured to transmit the reference signals for measuring the channel state information.