Aperiodic CSI-RS Allocation for Reducing Overhead in 5G MIMO Systems
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Solution Overview
Problem
The CSI-RS overhead has increased in mobile communication systems due to the increase in the number of antennas supported by base stations and the need for per-terminal CSI-RS functionality, particularly for UE-specific beamformed CSI-RS technology, necessitating a method to efficiently allocate and manage aperiodic CSI-RS for effective system operation.
Innovation Solution
The method involves enabling base stations to assign CSI-RS resource information in advance to terminals and trigger aperiodic CSI-RS allocation, allowing CSI-RS transmission without PDSCH in specific subframes or subbands, and dynamically managing resources using PCFICH, which allows for flexible port indexing and resource allocation based on the situation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of antennas supported by base stations is increased to meet 5G requirements, then system capacity and data rates are improved, but CSI-RS overhead increases significantly
Solution Approach 1:
The patent segments the CSI-RS transmission into two types: periodic CSI-RS for general channel state information and aperiodic CSI-RS for specific beamformed information. This segmentation allows the system to reduce overall overhead by only transmitting aperiodic CSI-RS when actually needed, rather than continuously transmitting full CSI-RS for all antennas
Solution Approach 2:
The patent implements dynamic aperiodic CSI-RS allocation where the base station can trigger CSI-RS transmission on demand based on actual system needs. The allocation is dynamically adjusted through DCI signaling, allowing the system to adapt CSI-RS transmission to current traffic conditions and reduce overhead when full antenna arrays are not actively being utilized
2Measurement precision
If per-terminal CSI-RS functionality is implemented for UE-specific beamformed transmission, then transmission precision and beamforming capability are improved, but device complexity and resource management difficulty increase
Solution Approach 1:
The patent configures multiple aperiodic CSI-RS resource sets in advance at the base station, each associated with specific beamforming parameters and terminal groups. When aperiodic CSI-RS needs to be transmitted, the base station simply triggers the pre-configured resource set through DCI signaling, avoiding complex real-time resource allocation decisions and reducing operational complexity
Solution Approach 2:
The patent creates a universal aperiodic CSI-RS resource framework that can serve multiple terminals with different beamforming requirements through a single standardized mechanism. The same DCI trigger format and resource configuration structure handles various beamforming scenarios, reducing the need for terminal-specific complex resource management
3Adaptability or versatility
If aperiodic CSI-RS is allocated dynamically using PCFICH, then resource allocation flexibility is improved, but control signaling overhead and system complexity increase
Solution Approach 1:
The patent introduces DCI signaling as an intermediary mechanism that carries compact aperiodic CSI-RS trigger information. Instead of complex direct resource allocation, the DCI serves as a simplified mediator that indicates which pre-configured resource set should be activated, reducing control signaling complexity while maintaining flexibility
Solution Approach 2:
The patent changes the parameter representation in control signaling by using compact DCI fields that reference pre-configured resource sets rather than explicitly specifying all resource parameters. This parameter transformation from detailed to reference-based representation reduces control overhead while preserving allocation flexibility
Data Source
AI summary
The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method by which a terminal receives a signal in a mobile communication system, according to one embodiment of the present specification, comprises the steps of: receiving channel state information-reference signal (CSI-RS) mode information; and receiving a signal on the basis of the CSI-RS mode information. Unlike a conventional method of allowing a base station to periodically set the CSI-RS in a terminal at a predetermined position such that the terminal receives the CSI-RS and generates and reports channel state information, the present invention proposes a method by which a base station allocates, to a terminal, a reference signal transmission for enabling aperiodic generation of the channel state information for a system having various numbers of transmission antenna ports such as one, two, four, eight, twelve, sixteen or thirty-two transmission antenna ports, and receives the channel state information report. In addition, a method for transferring ZP CSI-RS and quasi co-location (QCL) information for supporting rate matching thereby is also proposed.