Transmit Subarray Selection for MIMO Channel Orthogonality
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Solution Overview
Problem
In wireless communication systems utilizing high-frequency bands, especially in LOS scenarios, the orthogonality of channels between transmitting and receiving antenna arrays is compromised due to arbitrary orientations of receiving devices, leading to interference among data streams and degraded system performance.
Innovation Solution
A transmitting device determines a second projection array of the receiving antenna array in a second affine subspace and a first projection array in a first affine subspace, using information about the angle of departure and arrival, to establish a transmitting subarray that ensures orthogonality and reduces mutual interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the receiving device is located in an arbitrary direction with arbitrary orientation, then the adaptability of the communication system is improved, but the channel orthogonality deteriorates leading to data stream interference
Solution Approach 1:
The patent applies dimensionality change by projecting the receiving antenna array from its original arbitrary orientation into a standardized coordinate system. The projection unit transforms the receiving antenna array coordinates into projection coordinates through mathematical projection operations, effectively converting a 3D arbitrary orientation problem into a 2D standardized plane problem. This allows the system to maintain adaptability to various receiving device orientations while achieving channel orthogonality in the projected domain, thereby resolving the contradiction between orientation flexibility and channel orthogonality
Solution Approach 2:
The patent changes the coordinate system parameters from the original arbitrary orientation to a standardized projection coordinate system. By transforming the coordinates of the receiving antenna array elements from their original spatial positions to projected positions on a standard plane, the system maintains the physical flexibility of arbitrary device orientation while achieving mathematical orthogonality in the transformed parameter space. This parameter transformation resolves the contradiction by operating in a different coordinate representation
2Productivity
If multiple data streams are transmitted simultaneously through MIMO technique, then the spectral efficiency is improved, but the mutual interference between streams increases when orthogonality does not hold
Solution Approach 1:
The patent introduces a projection coordinate system as an intermediary transformation between the transmitting and receiving antenna arrays. Instead of directly transmitting multiple data streams through arbitrarily oriented antenna arrays which causes interference, the system first projects the receiving antenna array into a standardized coordinate system, then determines the transmitting antenna array configuration based on this projection. This intermediary transformation ensures that the channel matrices for different data streams become orthogonal, allowing multiple streams to be transmitted simultaneously without mutual interference, thus maintaining both high spectral efficiency and low interference
Data Source
AI summary
Embodiments of the present disclosure provide a receiving device and a transmitting device and corresponding methods. A transmitting device according to embodiments of the present disclosure includes: a transmitting unit including a first antenna array; and a control unit configured to determine a second projection array of a receiving antenna array of a receiving device in a second affine subspace of a receiving device, to determine a first projection array of a second projection array in a first affine subspace of the transmitting device and to determine a transmitting subarray in the first antenna array according to information about an angle of departure of a signal of the transmitting device and the first projection array.