MIMO Transceiver Leakage Cancellation via Frequency Division
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Solution Overview
Problem
The constraints on antenna positions in LOS-MIMO technology become prohibitive for cost-effective and straightforward deployment of radio links, especially over large distances and at low carrier frequencies, due to the need for precise relative phase shifts between transmit and receive antennas.
Innovation Solution
A transceiver arrangement that transmits and receives signals in two separate frequency bands, allowing for the suppression of in-band interference and relaxation of antenna position constraints, enabling simultaneous transmission and reception of multiple data streams with directive and steerable antennas, and incorporating a transmit interference cancellation device for improved signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LOS-MIMO technology is used to increase spectral efficiency, then multiple independent data streams can be communicated over a single frequency band, but constraints on relative antenna positions become prohibitive
Solution Approach 1:
The patent changes the operating parameters by using frequency division duplexing (FDD) with separate frequency bands for transmission and reception. This parameter change allows the system to achieve MIMO spectral efficiency without requiring the precise antenna spacing and positioning that characterizes traditional LOS-MIMO systems, thereby simplifying deployment while maintaining high productivity
2Length of moving object
If antenna spacing is increased to achieve LOS-MIMO communication over large distances, then communication range is improved, but antenna position constraints become more severe
Solution Approach 1:
The patent segments the frequency spectrum into separate transmission and reception bands. This segmentation allows the system to handle large distance communications without requiring precise antenna positioning, as the frequency separation enables independent optimization of transmit and receive antenna characteristics without the coupling constraints of traditional MIMO
3Productivity
If transmit and receive signals share the same frequency band in LOS-MIMO, then spectral efficiency is maximized, but self-interference and in-band interference occur
Solution Approach 1:
The patent extracts the interference problem by separating transmit and receive operations into different frequency bands. This extraction removes the self-interference and in-band interference that plagues traditional MIMO systems, while still enabling multiple data streams to be communicated simultaneously through the use of frequency diversity and multiple antennas
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
A transceiver arrangement (200) for a fixed point-to-point radio link. The transceiver arrangement (200) comprising a transceiver (215) connected to a first antenna (210) and to a second antenna (220). The transceiver (215) being arranged to transmit a first transmit signal (211) via the first antenna (210) in a first frequency band (f1), the transceiver (215) also being arranged to receive a first receive signal (212) via the first antenna (210) in a second frequency band (f2), the transceiver (215) further being arranged to transmit a second transmit signal (221) via the second antenna (220) in the second frequency band (f2), the transceiver (215) also being arranged to receive a second receive signal (222) via the second antenna (220) in the first frequency band (f1).