MU-MIMO Base Station Signal Processing for Backward Compatibility
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Solution Overview
Problem
Communication systems using MU-MIMO THP and MU-MIMO VP face compatibility issues when interacting with mobile station devices that do not perform modulo arithmetic, leading to a lack of backward compatibility and inability to spatially multiplex signals across different communication systems.
Innovation Solution
A communication system that includes a first communication device capable of performing equivalent conversion and canceling interferences among spatially multiplexed streams, and a second communication device that can reconstruct data signals received after equivalent conversion, with mechanisms to determine THP compliance and adjust transmission accordingly, using common and dedicated reference symbols for channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MU-MIMO THP or MU-MIMO VP is used to achieve spatial multiplexing, then throughput is improved, but backward compatibility is lost because devices without modulo arithmetic cannot receive the signals
Solution Approach 1:
The patent segments the mobile station devices into two types: THP-compliant devices that can perform modulo arithmetic and THP-non-compliant devices that cannot. The base station device then transmits different signal processing methods to different device types, allowing spatial multiplexing with THP-compliant devices while maintaining compatibility with THP-non-compliant devices through alternative signal processing.
Solution Approach 2:
The base station device applies different signal processing characteristics to different mobile station devices based on their THP compliance status. For THP-compliant devices, the base station performs equivalent conversion and modulo arithmetic; for THP-non-compliant devices, the base station uses conventional linear processing. This local differentiation enables both high throughput and backward compatibility.
2Productivity
If beamforming is used for spatial multiplexing, then spatial efficiency is improved, but flexibility of device combinations is reduced due to orthogonality requirements
Solution Approach 1:
The base station device dynamically determines the signal processing method based on the THP compliance status of each mobile station device. The system can adaptively switch between THP-based spatial multiplexing for high throughput and conventional beamforming for compatibility, allowing flexible combination of different device types in the same network.
Data Source
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AI summary
A communication device on the transmission side includes: a converting device configured to perform equivalent conversion on a part of the plurality of data signals; and a weighting device configured to previously cancel at least a part of interferences among the plurality of streams spatially multiplexed, with respect to at least a part of the plurality of data signals.