Multi-User Multiplexing via Joint Precoding for Spectrum Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE-Advanced systems, existing technologies lack effective multi-user multiplexing methods, particularly in open-loop scenarios, leading to inefficient spectrum utilization and increased interference among users.
Innovation Solution
A method for multi-user multiplexing involving layer mapping, pre-coding processing using calculated pre-coding matrices W1 and W2, and mapping data to transmission antennas, which optimizes signal-to-interference noise ratio (SINR) and reduces interference by eliminating the zero space vector of the channel matrix H1, allowing for simultaneous transmission of open-loop and close-loop user data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only diversity transmission is used in open-loop mode, then transmission reliability is maintained, but spectrum utilization ratio is low
Solution Approach 1:
The patent combines open-loop and close-loop user multiplexing by merging their precoding processing in the same time-frequency resources. The base station performs joint precoding for both open-loop users (using spatial diversity) and close-loop users (using channel state information), allowing simultaneous transmission to multiple users with different mobility characteristics, thereby improving spectrum utilization while maintaining reliability
Solution Approach 2:
The patent dynamically adapts the precoding strategy based on user mobility characteristics. For open-loop users with high mobility, spatial diversity precoding is used without requiring frequent channel feedback. For close-loop users with lower mobility, channel-state-dependent precoding is applied. This dynamic adaptation allows the system to optimize performance for different user types simultaneously, improving overall spectrum efficiency
2Productivity
If multiple close-loop users are multiplexed, then spectrum utilization improves, but interference management becomes complex and performance degrades when users are unsuitable for pairing
Solution Approach 1:
The patent segments the user set into open-loop users and close-loop users based on mobility characteristics and channel conditions. By separating users into different categories with different precoding strategies, the system simplifies interference management compared to attempting to multiplex all close-loop users together, which would require complex pairing algorithms and interference coordination
Solution Approach 2:
The patent introduces a unified precoding framework that acts as an intermediary between open-loop and close-loop transmission modes. This framework coordinates the precoding of both user types in a structured manner, avoiding the need for complex ad-hoc interference management between close-loop users while still enabling multi-user multiplexing
3Productivity
If open-loop and close-loop users share the same resources, then spectrum utilization increases, but interference between users increases
Solution Approach 1:
The patent applies different precoding qualities to different user types: open-loop users receive spatial diversity precoding optimized for high mobility and fading resistance, while close-loop users receive channel-state-optimized precoding. This local optimization of precoding quality for each user type reduces mutual interference while enabling resource sharing
Data Source
AI summary
The present invention provides a method and apparatus for multi-user multiplexing. The method includes: a transmission apparatus performing layer mapping on data steams to be transmitted of an open-loop user and a close-loop user respectively; the transmission apparatus performing pre-coding processing on a layer data matrix of the open-loop user and the close-loop user obtained by the layer mapping; and the transmission apparatus mapping the layer data matrix after the pre-coding processing to a plurality of transmission antennas to be sent. The method of the present invention can improve frequency spectrum utilization ratio in the case of the a cell being full load or other possible scenarios, and its performance is better than the multiplexing of two close-loop users who are completely not suitable for pairing. Therefore, the method of the present invention is an optimal scheme adopted in some specified scenarios.