Shared Local Oscillator Architecture for Multi-Band FDD Transceivers
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Solution Overview
Problem
Multi-band frequency division duplex (FDD) transceivers face challenges in reducing the number of local oscillators (LOs) used, which leads to increased power dissipation and chip area, and generates spurious issues due to the complexity of integrating multiple components in a single integrated circuit.
Innovation Solution
A multi-band FDD transceiver system that shares a single LO signal between the receiver and transmitter paths, utilizing quadrature signal processing to downconvert and upconvert signals across multiple frequency bands, reducing the number of LOs required and minimizing spurious issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple local oscillators are used in multi-band FDD transceivers, then frequency conversion capabilities across multiple bands are maintained, but power dissipation increases and chip area expands
Solution Approach 1:
The patent combines multiple local oscillator functions into a single shared LO that serves both receiver and transmitter paths across multiple frequency bands. The LO is time-shared between RX and TX operations, eliminating the need for separate oscillators for each band and path, thereby reducing power consumption while maintaining multi-band frequency conversion capabilities.
Solution Approach 2:
The single local oscillator is designed to perform multiple functions: it generates LO signals for both receiver and transmitter paths, supports multiple frequency bands (e.g., Band 1 and Band 3), and provides frequency conversion through mixing operations. This multi-functional approach replaces what would traditionally require multiple dedicated oscillators.
2Adaptability or versatility
If multiple local oscillators are used in multi-band FDD transceivers, then frequency conversion capabilities across multiple bands are maintained, but chip area increases
Solution Approach 1:
The patent merges multiple local oscillator circuits into a single shared LO unit that is time-shared between receiver and transmitter operations. This consolidation significantly reduces the chip area required compared to having separate oscillators for each frequency band and path, while still enabling multi-band frequency conversion through proper timing and frequency selection.
3Adaptability or versatility
If multiple local oscillators are integrated in a single IC, then multi-band operation is supported, but spurious issues increase due to generation and distribution complexity
Solution Approach 1:
By consolidating multiple LO functions into a single oscillator, the patent eliminates the complex distribution network required for multiple oscillators. This single LO approach reduces the number of signal paths and potential interference points, thereby minimizing spurious issues while maintaining multi-band operation capabilities through time-division and frequency management.
4Use of energy by moving object
If a single LO is shared between RX and TX paths, then power consumption decreases and design is simplified, but LO signal sharing complexity arises
Solution Approach 1:
The patent implements periodic time-division operation where the single LO alternates between serving the receiver path and the transmitter path. The LO is enabled during RX operations and disabled during TX operations, or vice versa, creating a periodic usage pattern that simplifies the sharing mechanism compared to continuous operation and reduces power consumption.
Solution Approach 2:
The LO sharing mechanism is made dynamic through time-division control, where the LO frequency and enabling are adjusted based on whether the system is in RX or TX mode. This dynamic approach allows a single LO to adaptively serve different functions at different times, simplifying the overall design while managing the complexity of signal sharing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the number of LOs, decreases power consumption, and simplifies the design, while maintaining effective frequency conversion capabilities across multiple bands, thereby enhancing the efficiency and scalability of the transceiver system.
Implementation Method 1
The LO is configured to provide an LO signal to be mixed with received RF signals
Implementation Method 2
The LO is configured to provide an LO signal to be mixed with transmitted signals
Implementation Method 3
utilizing quadrature signal processing to downconvert and upconvert signals across multiple frequency bands
Data Source
AI summary
Embodiments of the present disclosure relate to multi-band FDD transceivers. An example transceiver includes a LO, configured to generate a LO signal to be shared between a receiver and a transmitter of the transceiver. Both the receiver and the transmitter use quadrature signal processing and are configured to multi-band operation. Sharing a single LO to perform frequency conversion of different frequency bands of received and transmitted signals advantageously allows reducing the number of LOs used in a multi-band FDD transceiver.