Flexible CSI-RS Configuration for FD-MIMO Antenna Port Grouping
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Solution Overview
Problem
Current CSI-RS protocols in LTE-Advanced systems face limitations in supporting higher numbers of antennas and optimal channel quality, particularly with the trend towards Full-Dimensional MIMO configurations that require adaptation in both azimuth and elevation, leading to suboptimal channel state information measurements.
Innovation Solution
A new, flexible CSI-RS protocol that allows for a more flexible assignment of antenna ports and supports an increasing number of antennas, enabling optimal channel quality by configuring CSI-RS groups to correspond with various antenna configurations, including those for FD-MIMO, allowing for better channel state information measurement and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional CSI-RS protocols are used, then compatibility with existing LTE-Advanced systems is maintained, but support for higher numbers of antennas and FD-MIMO configurations is limited
Solution Approach 1:
The patent applies dynamics by making the CSI-RS configuration flexible and adaptable. The eNB can dynamically configure different numbers of CSI-RS antenna ports (1, 2, 4, or 8 ports) based on the specific antenna configuration and FD-MIMO requirements. This allows the system to adapt to varying numbers of antennas without requiring a completely new protocol, thus improving versatility while managing complexity through dynamic configuration rather than static redesign.
Solution Approach 2:
The patent segments the antenna ports into multiple CSI-RS groups, where each group corresponds to a specific set of antenna ports (1-port, 2-port, 4-port, or 8-port configurations). This segmentation allows the system to handle large numbers of antennas by dividing them into manageable groups, each with its own CSI-RS configuration. The UE can be configured with multiple CSI-RS groups simultaneously, enabling support for high-numbered antenna configurations while maintaining protocol manageability through structured grouping.
2Measurement precision
If fixed CSI-RS antenna port assignments are used, then protocol simplicity is maintained, but optimal channel quality measurement for FD-MIMO is not achieved
Solution Approach 1:
The patent applies local quality by assigning different CSI-RS configurations to different antenna port groups based on their specific requirements. Each CSI-RS group is configured with appropriate antenna ports and measurement parameters tailored to the local characteristics of that antenna group. This allows optimized channel state information measurement for each antenna configuration while maintaining overall protocol simplicity through standardized group definitions. The UE can be configured with multiple CSI-RS groups, each with locally optimized parameters for accurate channel quality measurement.
3Reliability
If CSI-RS symbols are transmitted on all antenna ports, then complete channel state information is obtained, but downlink channel quality deteriorates due to suboptimal resource allocation
Solution Approach 1:
The patent applies parameter changes by allowing dynamic adjustment of CSI-RS configuration parameters including the number of antenna ports, resource block allocation, and time frequency positioning. The eNB can change these parameters based on channel conditions and FD-MIMO requirements to optimize both channel quality and resource allocation efficiency. This enables the system to transmit CSI-RS symbols on the most appropriate antenna ports and resource blocks, improving reliability while maintaining productivity through adaptive parameter adjustment rather than fixed allocation.
Data Source
AI summary
Described are an eNB and a UE implementing a CSI-RS protocol. The eNB has an ordered set of antenna ports for a wireless communication channel with the UE, a first circuitry operable to compose CSI-RS configuration messages that assign to the UE various CSI-RS groups specifying one or more CSI-RS antenna ports, and a second circuitry to establish an ordered list of CSI-RS antenna ports. The UE has a set of antennas, a first circuitry operable to receive from the eNB various CSI-RS configuration messages assigning to it CSI-RS groups specifying one or more CSI-RS antenna ports, and a second circuitry operable to index CSI-RS antenna ports specified by the CSI-RS groups as an ordered list of CSI-RS antenna ports. The eNB may transmit CSI-RS to the configured UE, and the UE may perform channel state information measurements on the ordered list of CSI-RS antenna ports.