RF Receiver Carrier Aggregation Single Local Oscillator
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Solution Overview
Problem
Current RF receivers face challenges in efficiently handling carrier aggregation due to high dynamic range and bandwidth requirements, which lead to increased current consumption and silicon area, as well as interference between local oscillators in multiple receiver paths, making it difficult to implement effective frequency synthesizers and LO-dividers.
Innovation Solution
The RF receiver employs a Finite Impulse Response (FIR) mixer with a complex filter having a programmable center frequency, using weighted delayed versions of the local oscillator signal to achieve efficient harmonic rejection and down-conversion, allowing for simultaneous reception of multiple frequency bands with a single receiver path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple parallel receiver paths are used to meet carrier aggregation requirements, then the receiver can simultaneously receive multiple frequency bands, but the device complexity and silicon area increase significantly
Solution Approach 1:
The patent merges multiple receiver paths into a single receiver path by using a time-division multiplexed switch that alternately connects different antenna elements to the same receiver chain. This allows the receiver to process multiple frequency bands sequentially rather than requiring parallel paths, thereby reducing device complexity while maintaining carrier aggregation capability.
Solution Approach 2:
The patent introduces dynamic switching between different antenna elements and frequency bands using a time-division multiplexed approach. The receiver dynamically reconfigures its connection to different antennas at different time slots, enabling flexible adaptation to various carrier aggregation scenarios without requiring dedicated hardware for each frequency band.
2Adaptability or versatility
If the receiver bandwidth and dynamic range are increased to handle multiple frequency bands, then simultaneous reception of multiple bands becomes possible, but current consumption increases
Solution Approach 1:
The patent employs periodic time-division multiplexed switching to alternate between different frequency bands and antenna elements. Instead of continuously processing all bands simultaneously with high bandwidth, the receiver periodically switches between bands, allowing each band to be processed with optimized bandwidth settings, thereby reducing overall current consumption while maintaining the ability to receive multiple bands.
3Reliability
If multiple voltage-controlled oscillators are used in parallel receiver paths, then each path can operate independently, but the oscillators interfere with each other and frequency synthesizer implementation becomes complicated
Solution Approach 1:
The patent merges the local oscillator functions by using a single frequency synthesizer that generates a common clock signal for the time-division multiplexed receiver. This eliminates the need for multiple independent voltage-controlled oscillators, thereby removing oscillator interference issues and simplifying the frequency synthesizer implementation while maintaining reliable reception through sequential processing.
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 solution enables efficient RF receivers with improved harmonic rejection capabilities, reduced power consumption, and increased area efficiency, supporting a wide range of IF frequencies and carrier aggregation scenarios while maintaining synchronization across multiple receivers.
Implementation Method 1
down-convert the IF signal using a Finite Impulse Response (FIR) mixer (10), wherein the FIR mixer is configured to provide a weighted sum of the IF signal mixed with differently delayed versions of a second LO signal
Data Source
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Figure 3a~3b
AI summary
A Radio Frequency, RF, receiver (100) is provided. The RF receiver is configured to simultaneously receive at least two radio frequency bands with a single receiver path. The RF receiver comprises a single local oscillator, LO, and the RF receiver is configured to filter a received signal using a complex filter (50) having a variable center frequency. Hereby an efficient RF receiver for receiving multiple carriers can be implemented. In accordance with another aspect many RF receivers (100) are combined to form an efficient aggregate carrier receiver.