Local Oscillator Frequency Control Around Reference Signal Bands
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Solution Overview
Problem
Existing communication devices face challenges in minimizing the adverse effects of local oscillator (LO) signals on carrier signals within a predetermined radio frequency (RF) band, which can impact channel estimation and reception performance due to overlapping frequencies.
Innovation Solution
A method and semiconductor/communication device that dynamically adjusts the LO frequency to avoid reference signal bands within the carrier band, using processing circuitry to determine carrier and reference signal bands and generate a control signal to compensate for the LO frequency, ensuring it does not overlap with reference signal bands, thereby improving channel estimation and reception performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the LO frequency is set within the carrier band to improve spectral efficiency, then the RF bandwidth can be reduced, but the LO signal overlaps with reference signal bands causing degradation in channel estimation and reception performance
Solution Approach 1:
The patent applies local quality by making the LO frequency selection specific to the reference signal band locations. Instead of using a fixed LO frequency or a generic avoidance strategy, the system dynamically selects the LO frequency based on the specific allocation of reference signal bands within the carrier band. This localized adaptation ensures that the LO signal avoids interfering with reference signals while maintaining spectral efficiency, directly resolving the contradiction between RF bandwidth reduction and channel estimation performance.
2Reliability
If the LO frequency is adjusted to avoid reference signal bands, then channel estimation performance is improved, but the device complexity increases due to dynamic frequency selection
Solution Approach 1:
The patent implements feedback by using the known reference signal band allocation information (obtained from network configuration or resource allocation messages) to dynamically determine the appropriate LO frequency. The processing circuitry receives information about reference signal band locations and automatically adjusts the LO frequency accordingly. This feedback mechanism enables automatic adaptation without requiring complex manual configuration or trial-and-error approaches, thus improving reception performance while keeping the complexity increase manageable.
3Device complexity
If a fixed LO frequency is used to simplify the system, then device complexity is reduced, but the LO signal may overlap with reference signal bands in certain carrier allocations
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed LO frequency approach to a dynamic frequency selection mechanism. The LO frequency is no longer static but is instead adjusted based on the specific carrier band allocation and reference signal band positions. This dynamic adaptation allows the system to maintain simplicity in normal operation while automatically responding to different allocation scenarios, thereby reducing LO signal interference without requiring overly complex control mechanisms.
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 minimizes the adverse effects of LO signals on carrier signals, enhances channel estimation, and improves reception performance by ensuring the LO frequency does not overlap with reference signal bands, even in scenarios with limited RF bandwidth, thus optimizing communication device performance.
Implementation Method 1
A frequency mixer is used to convert a baseband signal into a carrier signal. When a local oscillator (LO) signal is applied to the mixer, a carrier signal having a shifted center frequency may be generated while including baseband signal information.
Data Source
AI summary
A semiconductor device including processing circuitry configured to determine a carrier band and reference signal bands based on a data signal received from a network, the carrier band and reference signal bands being allocated by the network, the reference signal bands corresponding to a reference signal for channel estimation, and the reference signal being within a carrier band, and output a control signal causing a local oscillator (LO) to change a LO frequency to a value that does not overlap the reference signal bands.