Open Loop Spatial Multiplexing Precoding for Multi-User MIMO
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Solution Overview
Problem
Current open loop spatial multiplexing technologies do not support multi-user scenarios and are limited to single-polarized antenna channels, lacking effective precoding solutions for multiple antennas, especially in dual-polarized antenna scenarios and with 8 transmission antennas.
Innovation Solution
A precoding method and system for open loop spatial multiplexing that involves the base station precoding N-layer data using a vector or matrix related to the transmission resource location, with specific scalar and vector relationships, and optionally precoding M-layer data with orthogonal or subset relationships, to support multiple antennas and users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If open loop spatial multiplexing uses fixed precoding matrices for single user, then implementation is simple, but it does not support multi-user scenarios and multiple antennas
Solution Approach 1:
The precoding process is segmented into two independent stages: first, selecting a base precoding matrix from a codebook based on PMI feedback, and second, applying a differential phase shift based on SRI. This segmentation allows the system to support multiple users and antennas while keeping each stage relatively simple and manageable.
Solution Approach 2:
The precoding matrix is made dynamic by allowing it to change based on SRI (Scheduled Resource Indicator) values. Different SRI values correspond to different differential phase shifts, enabling the system to adapt to multi-user scenarios and varying channel conditions without requiring completely new precoding matrices for each case.
2Reliability
If closed loop spatial multiplexing uses channel state information feedback, then transmission performance is greatly improved, but it is not applicable when uplink feedback link quality is poor or terminal movement speed is very fast
Solution Approach 1:
The system performs preliminary action by pre-configuring multiple precoding matrices in the codebook and pre-establishing the relationship between SRI values and differential phase shifts. This allows the receiver to select appropriate precoding matrices based on PMI feedback without requiring real-time channel state information, making the system reliable in poor feedback conditions.
Solution Approach 2:
The system enables self-service by allowing the receiver to autonomously select precoding matrices based on PMI feedback and SRI values without requiring continuous channel state information feedback. The transmitter and receiver both have the same codebook, enabling the receiver to independently determine the appropriate precoding matrix.
3Adaptability or versatility
If open loop spatial multiplexing uses codebook-based precoding, then it supports multiple antennas, but it lacks differential phase shift mechanisms for multi-user support
Solution Approach 1:
Instead of designing completely different precoding matrices for each user, the system applies partial modification by introducing differential phase shifts to base precoding matrices. This excessive action of using the same base matrices with different phase shifts enables multi-user support while avoiding the complexity of designing entirely separate precoding solutions for each user.
Data Source
AI summary
The present document provides a precoding method and system for open loop spatial multiplexing and a precoding indication method. The method includes: in transmission resources, a base station precodes N-layer data to be sent by using wa=uaαua, wherein ua is a vector or matrix related to a transmission resource location i; α is a real number or a complex number related to the transmission resource location i; and N is an integer less than or equal to the number of base station transmission antennas. The present document can implement effective precoding in the case of open loop spatial multiplexing, and can also support the multiple antennas (such as 8 transmission antennas) application.