Frequency Offset Estimation via Accumulated Deviation Values

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Frequency offset (FO) is a major impairment that degrades the performance of Bluetooth (BT) receivers, causing decision errors, especially in low signal-to-noise ratio (SNR) or multipath environments.

Innovation Solution

A method and apparatus for estimating frequency offset by accumulating complete frequency deviation (FD) values of samples obtained from sampling a frequency-modulated repetition-coded segment of a packet, specifically using the repetition-coded header for optimal FO estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frequency offset compensation is not applied, then the receiver structure remains simple, but decision errors increase in low SNR or multipath environments

Engineering Contradiction:

Improvedecision accuracyVSAvoidreceiver structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs frequency offset estimation using the repetition-coded header section before decoding the main packet data. By pre-estimating the frequency offset from the known repetition structure in the header, the system prepares compensation parameters in advance that will be applied during subsequent data decoding, thereby improving decision accuracy without adding complexity to the main decoding path

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The repetition-coded header structure is inherently designed to enable self-estimation of frequency offset. The system uses the redundant information within the header itself (where each bit is repeated multiple times) to automatically determine the frequency offset without requiring external reference signals or complex training sequences, making the receiver serve its own calibration needs

Inventive Principle:

Principle #25Self-service

2Measurement precision

If frequency offset estimation uses all available samples, then estimation precision improves, but processing time increases

Engineering Contradiction:

Improvefrequency offset estimation precisionVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the packet structure into distinct segments: a repetition-coded header section and a main data section. Frequency offset estimation is performed exclusively on the header segment, which contains sufficient redundant information due to the repetition coding scheme. This segmentation allows the system to obtain adequate estimation precision from a limited, well-chosen subset of samples rather than processing the entire packet

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system applies partial action by using only the header portion for frequency offset estimation rather than processing all packet samples. The repetition-coded header provides excessive (redundant) information that is sufficient for accurate estimation, allowing the system to stop processing once the header is analyzed, thereby reducing overall processing time while maintaining estimation precision

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12278724B2Method and apparatus for estimating frequency offset through accumulating complete frequency deviation values of samples obtained from sampling frequency-modulated repetition-coded segment of packet

Publication Date: 2025.04.15 AIROHA TECHNOLOGY CORPORATION

AI summary

A frequency offset (FO) estimation method includes: sampling a frequency-modulated repetition-coded segment of a packet to generate a plurality of samples; obtaining a frequency deviation (FD) value for each of a plurality of target samples selected from the plurality of samples; and estimating an FO value through accumulating complete FD values of the plurality of target samples.