TDD Transceiver Isolation via Interference Cancellation
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Solution Overview
Problem
Traditional wireless communication systems are half-duplex, limiting their performance when some devices are transmitting and others are receiving, due to interference from coexisting time-division duplexed (TDD) transceivers operating in the same frequency band.
Innovation Solution
A system for enhanced-isolation coexisting TDD transceivers, incorporating tunable filters, analog and digital blockers cancellers, local oscillator exchangers, and antenna thru-matchers, which reduce interference by mitigating the effects of transmit signals and noise in the receive channel, using a combination of digital and analog circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time-division duplexing is used to enable simultaneous transmission and reception on the same frequency channel, then wireless communication performance is improved, but interference between coexisting TDD transceivers increases
Solution Approach 1:
The patent introduces an isolation system as an intermediary component between coexisting TDD transceivers. This isolation system includes isolation filters, cancellers, and matchers that act as mediators to reduce the harmful interference between transceivers while allowing them to operate simultaneously on the same frequency channel, thus resolving the contradiction between improved productivity and increased harmful factors
Solution Approach 2:
The patent applies interference cancellation techniques that convert the harmful interference signals into useful information. By using the transmitted signal as a reference, the system generates cancellation signals that are subtracted from the received signal, effectively converting the interference from a harmful factor into a beneficial cancellation mechanism, thereby enabling simultaneous transmission and reception without performance degradation
2Adaptability or versatility
If coexisting TDD transceivers operate in the same frequency band on different channels, then device versatility is improved, but signal degradation in receiving transceivers increases
Solution Approach 1:
The patent applies local quality by implementing frequency-selective isolation filters that are specifically tuned to block interfering frequencies from adjacent channels while allowing desired signals to pass. Each filter is locally optimized for its specific frequency band, providing targeted interference rejection that maintains signal reliability while enabling versatile multi-channel operation
Solution Approach 2:
The patent employs dynamic parameter adjustment through tunable filters and cancellers that can adapt their characteristics based on the operating conditions. The isolation system dynamically changes its frequency response and cancellation parameters to match the specific transmission and reception patterns of coexisting TDD transceivers, thereby maintaining signal quality across different frequency bands and operational modes
Data Source
AI summary
A system for enhancing isolation in coexisting time-division duplexed (TDD) transceivers includes: a blocker canceller that transforms a transmit signal of a TDD transceiver into a blocker cancellation signal configured to remove transmit-band interference in a receive signal; a first filter that filters the blocker cancellation signal; a second filter that filters the transmit signal; and a transmit-noise canceller that transforms the filtered transmit signal into a transmit noise cancellation signal configured to remove receive-band interference in the receive signal.