2D Massive MIMO Channel Feedback Using 1D Array Segmentation
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Solution Overview
Problem
In 5G mobile communication systems, especially those employing Full Dimension MIMO (FD-MIMO) with a large number of transmit antennas, there is a need for a method to efficiently measure channel state information (CSI) with low overhead and report it back to the base station, as existing methods consume excessive radio resources, reducing data transmission capacity and system throughput.
Innovation Solution
The method involves transmitting horizontal and vertical direction reference signals (RS) from the base station to the terminal, allowing the terminal to measure and report CSI using a reduced number of CSI-RS ports, thereby optimizing resource allocation between CSI transmission and data traffic, and employing a codebook of precoding matrices suitable for 2-dimensional antenna structures to select the best precoding matrix for channel estimation and feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing CSI measurement methods are used in FD-MIMO systems with large number of transmit antennas, then channel state information can be obtained, but radio resource overhead increases excessively
Solution Approach 1:
The patent segments the 2D antenna array into multiple 1D antenna arrays (e.g., horizontal and vertical arrays). Each 1D array is assigned a separate CSI-RS port, reducing the total number of ports needed compared to assigning individual ports to each antenna element. This segmentation allows efficient CSI measurement while reducing resource overhead.
Solution Approach 2:
The patent makes CSI-RS ports serve multiple functions by assigning them to represent multiple physical antennas through 1D array mappings. A single CSI-RS port can represent multiple antenna elements within a 1D array, allowing the system to measure channel states for many antennas using fewer dedicated ports, thus reducing overhead while maintaining measurement capability.
2Measurement precision
If more CSI-RS ports are allocated for measuring channels of multiple transmit antennas, then measurement accuracy improves, but data transmission capacity decreases
Solution Approach 1:
By segmenting the antenna array into 1D sub-arrays and allocating CSI-RS ports at the sub-array level rather than individual antenna level, the patent reduces the number of ports required for accurate channel measurement. This frees up more radio resources for data transmission while maintaining sufficient measurement accuracy through the structured 1D array approach.
Solution Approach 2:
The patent transitions from a 2D antenna array structure to multiple 1D antenna array representations. This dimensionality reduction allows the system to capture essential channel characteristics using fewer CSI-RS ports, thereby balancing measurement accuracy with available resources for data transmission.
3Difficulty of detecting and measuring
If individual CSI-RS ports are assigned to each transmit antenna, then channel measurement is simplified, but system complexity increases
Solution Approach 1:
The patent segments the complex 2D antenna array into simpler 1D antenna arrays, each managed by a single CSI-RS port. This segmentation simplifies the measurement process compared to individual antenna mapping, as the system only needs to manage CSI-RS ports at the 1D array level rather than at each antenna element level, reducing system complexity while maintaining measurement capability.
Data Source
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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 channel state information feedback method and apparatus of a terminal is provided for measuring channel quality and reporting the measurement result to a base station in the mobile communication system supporting multi-carrier multiple access scheme such as Orthogonal Frequency Division Multiple Access (OFDMA). A feedback method of a terminal in a mobile communication system includes acquiring reference antenna port information for at least one Reference Signal (RS), receiving the at least one Reference Signal (RS) from a base station, estimating at least one channel carrying the at least one Reference Signal (RS), and transmitting feedback information on at least one estimated channel to the base station.