Adaptive Bluetooth Receiver Using Preamble DC Estimation
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Solution Overview
Problem
Conventional Bluetooth receivers face issues with incorrect DC offset estimation, susceptibility to interference, and low sensitivity due to uneven binary codes in access codes, lack of frame synchronization, and absence of redundant training patterns.
Innovation Solution
A Bluetooth receiver and method that adaptively utilize the Bluetooth frame structure by employing a RF front end, DC estimator, and frame synchronizer to improve DC offset estimation and frame synchronization, incorporating a 34-bit pseudo-number for synchronization and channel estimation to enhance sensitivity and interference immunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Bluetooth receivers use access code for DC offset estimation, then the receiver can perform basic reception, but DC offset estimation accuracy is incorrect due to uneven binary code distribution
Solution Approach 1:
The patent applies preliminary action by using the preamble sequence (which has evenly distributed binary codes) to perform DC offset estimation before the actual data transmission begins. This preliminary estimation using the preamble ensures accurate DC offset compensation is established before processing the potentially interfering data portion, resolving the contradiction between basic reception capability and estimation accuracy.
2Object-affected harmful factors
If Bluetooth receivers implement gain control with one-frame delay after RSSI detection, then the receiver can maintain simplicity, but interference immunity deteriorates due to delayed response
Solution Approach 1:
The patent implements preliminary action by performing RSSI detection and gain control adjustment during the preamble reception phase, before the actual data frames are received. This advance gain control setup eliminates the one-frame delay, allowing the receiver to adapt to interference levels proactively rather than reactively, thereby improving interference immunity without time loss.
3Reliability
If Bluetooth packets do not include redundant training patterns, then the packet structure remains efficient, but sensitivity cannot be improved due to lack of equalizer training data
Solution Approach 1:
The patent applies universality by making the preamble sequence serve multiple functions simultaneously: it provides frame synchronization, enables DC offset estimation, and supplies training data for equalizer adaptation. This multi-functional use of the preamble eliminates the need for separate redundant training patterns in the data portion, improving sensitivity without increasing overall packet structure complexity.
Data Source
AI summary
A Bluetooth receiver comprises a RF front end configured to receive a Bluetooth signal including a preamble and 34-bit pseudo-number (PN); a DC estimator communicatively coupled to the RF front end; and a frame synchronizer communicatively coupled to the DC estimator. The DC estimator is configured to perform DC offset estimation by determining an average value of samples of the preamble and the frame synchronizer is configured to use the 34-bit PN for frame synchronization.