Radio Front End Diversity Switch Linearity Reduction
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Solution Overview
Problem
Current radio front ends require high linearity in diversity switches to support band 7 (B7) FDD signals, increasing costs and complexity, especially when coexisting with the industrial, scientific, and medical (ISM) band, and do not efficiently support world phone or world tablet user equipment with three or more antennas for carrier aggregation and diversity reception.
Innovation Solution
A radio front end design with a modified diversity switch module that reduces linearity requirements by relocating the B7 filter to a mixed filter module and using a reduced linearity high band switch, allowing B7 RX signals to bypass the diversity switch module and be routed through ultrahigh band switch circuitry, thereby decreasing the linearity requirement from +79 dBm to around +57 dBm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If B7 filter is located within the diversity switch module and B7 FDD signals are passed through the high band switch, then signal routing for B7 diversity is achieved, but the linearity requirement for the high band switch increases to around +79 dBm
Solution Approach 1:
The B7 filter is extracted from the diversity switch module and relocated to the mixed filter module. This separation allows B7 FDD signals to bypass the high band diversity switch, thereby reducing the linearity requirement from +79 dBm to around +57 dBm while maintaining proper signal routing capability.
2Reliability
If high linearity diversity switch is used to support B7 FDD signals, then signal coexistence with ISM band is achieved, but device complexity and cost increase
Solution Approach 1:
The B7 filtering function is extracted from the diversity switch module and placed in the mixed filter module. This allows the use of a reduced linearity high band switch (around +57 dBm) instead of a high linearity switch (+79 dBm), thereby reducing device complexity and cost while maintaining signal coexistence capability with the ISM band.
3Device complexity
If B7 filter is relocated to mixed filter module and reduced linearity switch is used, then cost and complexity are reduced, but signal routing path must be modified
Solution Approach 1:
The B7 filter is relocated to the mixed filter module, and the B7 RX signal path is configured to bypass the diversity switch module through the mixed filter module and ultrahigh band switch circuitry. This modification reduces device complexity and cost, and while the routing path is modified, it integrates with existing module architectures.
Data Source
AI summary
A radio front end that includes a diversity switch module adapted to route diversity receive (RX) signals to transceiver circuitry from diversity antenna switch circuitry coupled to at least one diversity antenna port is disclosed. The radio front end further includes ultrahigh band (UHB) switch circuitry adapted to route UHB transmit (TX) signals from power amplifier and switch circuitry to a UHB antenna port and/or to at least one diversity antenna port. The UHB switch circuitry is also adapted to route UHB RX signals from the UHB antenna port and/or to at least one antenna port to the transceiver circuitry, wherein the UHB RX signals include band 7 (B7) wherein linearity of the UHB switch circuitry is greater than linearity of the diversity switch module.