Switch ON-State Linearization for UL-CA Distortion Cancellation
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Solution Overview
Problem
Wireless transceivers operating in up-link carrier aggregation (UL-CA) mode face linearity constraints due to non-linear distortion when passing high power transmit signals through main transistor-based switches, which existing technologies fail to adequately address.
Innovation Solution
An apparatus with a main transistor-based switch and an ON-state linearization network that cancels non-linear distortion by using a monitored signal to activate and deactivate the linearization network based on the switch's state, sharing a single control input and control line for both ON and OFF states to maintain high linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a main transistor-based switch is used to pass high power transmit signals in UL-CA mode, then the wireless transceiver can operate in up-link carrier aggregation mode, but non-linear distortion is generated that fails to meet linearity requirements
Solution Approach 1:
The patent uses the non-linear distortion generated by the main transistor-based switch as a feedback signal to drive the linearization network. The distorted signal, which would normally be harmful, is converted into a useful control signal that generates canceling distortion in the linearization network, thereby eliminating the original non-linear distortion and meeting UL-CA linearity requirements
Solution Approach 2:
The linearization network acts as an intermediary between the main transistor-based switch and the output. It receives the distorted signal from the switch, processes it through its own non-linear elements (such as FETs operated in specific regions), and outputs a corrected signal with the harmful non-linear components canceled out
2Reliability
If separate control inputs are used for ON and OFF state linearization networks, then linearity can be maintained in both states, but the quality factor is degraded
Solution Approach 1:
The patent merges the control inputs for the ON-state and OFF-state linearization networks into a single shared control input. The control signal is routed to both linearization networks through common control lines, reducing the total number of control inputs and associated routing infrastructure, thereby minimizing the impact on the quality factor while still providing linearization in both switch states
Data Source
AI summary
An apparatus including a main transistor-based switch having a first end node and a second end node and an ON-state linearization network that is coupled between the first end node and the second end node of the main transistor-based switch is disclosed. The ON-state linearization network is configured to receive a monitored signal that corresponds to a signal across the first end node and the second end node and cancel at least a portion of non-linear distortion generated by the main transistor-based switch when the main transistor-based switch is in an ON-state based on the monitored signal. A control signal applied to a control input of the ON-state linearization network causes the ON-state linearization network to activate when the main transistor-based switch is in the ON-state and to deactivate the ON-state linearization network when the main transistor-based switch is an OFF-state.