Receiver Sub-Band Frequency Offset Calibration in Wideband Channels
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Solution Overview
Problem
In wireless communication systems, frequency offsets between the transmitter and receiver due to carrier frequency and sampling clock mismatches affect communication performance, particularly in wideband channels, necessitating a method to accurately determine and compensate for these offsets.
Innovation Solution
A method and apparatus that determine frequency offsets by calibrating carrier frequency and sampling clock offsets at sub-bands within a wideband channel, combining these offsets to achieve accurate frequency compensation, regardless of the frequency position or bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency offset is determined using conventional methods in wideband systems, then carrier frequency alignment is attempted, but sampling clock and local oscillator clock mismatches cause frequency offset deviations across sub-bands, deteriorating measurement precision
Solution Approach 1:
The frequency band is divided into multiple sub-bands, and frequency offset is determined separately for each sub-band. This segmentation allows the system to account for variations in frequency offset across different sub-bands caused by sampling clock and local oscillator clock mismatches, thereby improving overall measurement precision without compromising communication reliability
Solution Approach 2:
Different frequency offset calibration methods are applied to different sub-bands based on their specific characteristics. The processor determines frequency offset for each sub-band individually and applies appropriate calibration, ensuring that local variations in frequency offset are accurately compensated, which improves both measurement precision and communication reliability
2Measurement precision
If single frequency offset determination is used for the entire frequency band, then processing complexity is reduced, but frequency offset variations across sub-bands are not accounted for, deteriorating measurement precision
Solution Approach 1:
The frequency band is segmented into multiple sub-bands for independent frequency offset determination. While this increases processing steps, each sub-band processing is standardized and automated by the processor, which manages the complexity efficiently. The segmentation enables accurate frequency offset measurement across sub-bands without overwhelming system complexity
Solution Approach 2:
The processor is designed to perform multiple functions: detecting signals across sub-bands, determining frequency offset for each sub-band, calibrating carrier frequency offset, and determining sampling clock offset. This multi-functionality consolidates complexity into a single processing unit, achieving high measurement precision without proportionally increasing overall device complexity
Data Source
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AI summary
An operating method of a receiver (100) includes detecting (S101) a signal received from a transmitter at a plurality of sub-bands constituting the frequency band, determining (S103) first frequency offsets for the signal at reception sub-bands at which the signal has been detected among the plurality of sub-bands, and determining (S105) second frequency offsets by calibrating carrier frequency offsets based on a distance of each of the reception sub-bands from a center frequency of the frequency band.