Bluetooth Interference Whitening for WLAN Reception
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Solution Overview
Problem
Multi-protocol combination devices with co-located WLAN and Bluetooth transceivers experience severe interference in the 2.4 GHz band, leading to degraded WLAN performance, especially when Bluetooth transmitters and WLAN receivers operate simultaneously, which can result in reception failures and limited throughput.
Innovation Solution
A Bluetooth interference whitening technique is employed, where a whitening matrix is computed based on a leakage signal during training mode, allowing for the de-correlation of interference across WLAN receiver chains, enabling simultaneous Bluetooth transmission and WLAN reception while optimizing demodulator performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Bluetooth and WLAN transceivers operate simultaneously in the same frequency band, then device functionality and communication versatility are improved, but interference between transceivers increases causing reception failures
Solution Approach 1:
A whitening filter is introduced as an intermediary component between the WLAN receiver and the signal processing chain. This filter processes the received signal to de-correlate interference from simultaneous Bluetooth transmissions, thereby maintaining WLAN reception reliability while allowing both transceivers to operate simultaneously
Solution Approach 2:
The system dynamically changes the whitening filter parameters based on the statistical properties of the interference signal. By adapting the filter to match the interference characteristics (such as correlation structure and power spectral density), the system effectively reduces interference impact while preserving desired WLAN signal quality
2Productivity
If Bluetooth transmitter and WLAN receiver operate at the same time, then data transmission efficiency is improved, but signal-to-noise ratio of WLAN signals deteriorates
Solution Approach 1:
The whitening filter is configured in advance based on training sequences or interference characterization performed during idle periods. This preliminary configuration allows the filter to be ready when Bluetooth transmission occurs, pre-establishing the optimal filtering parameters to maintain signal-to-noise ratio during simultaneous operation
Solution Approach 2:
The system continuously monitors the received signal quality and interference characteristics, using this feedback to dynamically adjust the whitening filter parameters. This closed-loop approach ensures that the filter adapts to changing interference conditions, maintaining optimal signal-to-noise ratio during simultaneous Bluetooth transmission and WLAN reception
3Device complexity
If co-located transceivers share the same transmission medium, then device complexity is reduced, but interference between protocols increases
Solution Approach 1:
The interference component is extracted from the received WLAN signal through the whitening filter operation. By identifying and removing the correlated interference portion that originates from the co-located Bluetooth transmitter, the system reduces harmful interference while maintaining the benefits of integrated transceiver design
Data Source
AI summary
The embodiments described herein are directed at techniques to de-correlate Bluetooth interference seen across WLAN receive antennas/space in a Bluetooth transceiver/WLAN transceiver combination device. A Bluetooth interference whitening technique may be utilized, wherein a whitening matrix is computed based on a leakage signal resulting from a training signal transmitted by the Bluetooth transceiver. The leakage signal may leak in to the WLAN transceiver and a set of attributes is calculated for each frequency the leakage signal is received on. One or more whitening matrixes are calculated based on the set of attributes for each frequency the leakage signal is received on. In response to the WLAN transceiver receiving a signal of interest, an appropriate whitening matrix from the one or more whitening matrixes is selected and is then applied to the received signal of interest to de-correlate any interference generated as a result of the Bluetooth transmission.