Diversity Front-End Circuit for Stable Multi-Band TDD Reception
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Solution Overview
Problem
Existing front-end circuits face challenges in maintaining accurate signal reception when simultaneously transmitting radio frequency signals across multiple communication bands due to phase changes caused by switching between transmission and reception modes, leading to deterioration in EVM and constellation accuracy.
Innovation Solution
A front-end circuit configuration that includes a primary circuit capable of simultaneous transmission in multiple bands and a diversity circuit with a switch that maintains a constant connection state, independent of the switching between transmission and reception modes, ensuring stable phase and accurate signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the switch in the diversity circuit changes connection state in response to transmission/reception mode switching in the primary circuit, then the diversity circuit can support simultaneous multi-band transmission, but the phase of the signal in the active signal path changes causing deterioration in EVM
Solution Approach 1:
The patent divides the diversity circuit into separate signal paths for different communication bands (first signal path for band 1, second signal path for band 2). Each signal path has its own switch that can be independently controlled, allowing the circuit to selectively activate only the necessary paths based on the transmission mode, thereby avoiding phase changes in inactive paths.
Solution Approach 2:
The patent implements dynamic control of switch connection states based on the operating mode (transmission or reception) of each signal path. The control unit adjusts the connection state of switches in real-time according to the active communication band and mode, ensuring that only the required signal paths are activated while others remain inactive, thus preventing phase fluctuations.
2Adaptability or versatility
If multiple switches change connection states simultaneously to support TDD in multiple bands, then multi-band TDD operation is enabled, but phase stability deteriorates causing EVM degradation
Solution Approach 1:
The patent segments the multi-band TDD system into independent signal paths, each with dedicated switches. This segmentation allows each path to be controlled independently, so when one path switches between transmission and reception modes, other paths remain unaffected, maintaining their phase stability.
Solution Approach 2:
The patent applies different connection states to different parts of the circuit (different signal paths) based on their local requirements. Each signal path's switch configuration is optimized for its specific band and mode, allowing local adaptation without affecting the global phase stability of other paths.
3Productivity
If the diversity circuit uses a switch configuration that responds to primary circuit mode changes, then simultaneous multi-band transmission is achieved, but signal reception accuracy decreases due to phase changes
Solution Approach 1:
The patent segments the diversity circuit into separate, independently controllable signal paths for different communication bands. Each path has its own switch that can be activated or deactivated based on the specific band being used, allowing simultaneous multi-band operation while maintaining phase stability in active paths.
Solution Approach 2:
The diversity circuit is designed with universal switches that can handle multiple communication bands and modes (transmission and reception) through a single unified structure. The control unit manages the multi-functionality by selectively activating appropriate paths, ensuring both high productivity and signal accuracy.
Data Source
AI summary
A front-end circuit includes a primary circuit and a diversity circuit, the primary circuit includes transmission paths 51 and 52 for transmitting a signal in a band A and in a band B, respectively. Transmission and reception of a signal in the band B are performed by a TDD system in the transmission path 52. The diversity circuit includes a switch, and reception paths 53 and 54 that receive a signal in the band A and in the band B, respectively. When reception signals in the band A and in the band B are simultaneously transmitted, and when a reception signal in the band A and a transmission signal in the band B are simultaneously transmitted, the switch causes the diversity antenna and each of the reception path 53 and the reception path 54 to be in a conductive state.