Dual-Connectivity RF Chain Control for 4G and 5G Coexistence
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Solution Overview
Problem
Wireless communication devices (WCDs) face challenges in supporting multiple air interface protocols concurrently, particularly in managing downlink communications through a common RF receive chain and handling uplink transmissions to avoid interference and regulatory compliance issues during the transition from 4G to 5G NR.
Innovation Solution
A WCD is configured with dynamic control of dual-stage split amplification and uplink transmission power, utilizing a common RF receive chain with separate LNAs for each modem, and power amplifiers for each modem, allowing for adaptive gain control and maximum power reduction based on operational conditions and frequency channel pairings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common RF receive chain is shared between 4G and 5G modems operating in the same frequency band, then device complexity is reduced, but signal reception quality deteriorates due to conflicting gain requirements of the two modems
Solution Approach 1:
The patent segments the RF receive chain into two separate paths after the common LNA: one path for the 4G modem and another path for the 5G modem. Each path has its own downconverter and baseband processor, allowing independent signal processing and gain control for each modem while sharing the common antenna and initial LNA stage.
Solution Approach 2:
The patent implements dynamic gain control where the first LNA gain is adjusted based on the signal strength requirements of the 4G modem, and the second LNA gain is independently adjusted based on the 5G modem's requirements. This dynamic adjustment allows the system to adapt to different signal conditions for each air interface protocol.
2Reliability
If uplink transmission power is maximized for both modems, then communication reliability improves, but out-of-band emissions increase causing regulatory compliance issues
Solution Approach 1:
The patent changes the power transmission parameters by applying maximum power reduction (MPR) values to the uplink transmissions. The MPR adjusts the transmit power level based on the frequency channel pairing between 4G and 5G modems, reducing power when channel conditions indicate potential out-of-band emissions while maintaining adequate communication reliability.
3Reliability
If separate LNAs are provided for each modem path, then signal reception quality for each modem is optimized, but device complexity and power consumption increase
Solution Approach 1:
The patent merges the first LNA and second LNA into a single integrated LNA component that provides dual-stage amplification. The first LNA stage amplifies the received signal with a first gain, and the second LNA stage provides additional amplification with a second gain, combining the functions of what would traditionally be separate LNA components into one unified structure.
Data Source
AI summary
Disclosed are structures and processes to help enable a wireless communication device (WCD) to support operation in a dual-connectivity scenario, such as where the WCD operates concurrently with 4G and 5G wireless connections over frequency channels in a common frequency band. Downlink low-noise-amplification could be controlled with a split dual-stage arrangement and control communication between modems in the WCD. And uplink maximum-power reduction could be controlled based on an evaluation of the frequency channels used by the respective connections, given knowledge of frequency resources allocated for one of those connections, and with a presumed worst-case-scenario frequency-resource allocation on the other connection.