Bluetooth Slave Beamforming via Implicit Channel Estimation
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Solution Overview
Problem
Current Bluetooth wireless communication systems face limitations in extending transmission distance and improving signal-to-noise ratio (SNR), particularly in environments where multiple piconets operate in close proximity, due to the lack of effective beamforming capabilities in slave devices with single antennas.
Innovation Solution
The implementation of a wireless communication apparatus with multiple antennas that supports implicit beamforming, allowing for channel estimation and the application of beamforming coefficients to enhance signal transmission, even when communicating with master devices that do not support beamforming, through the use of adaptive frequency hopping and time-division duplex schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency hopping is used to support multiple piconets in close proximity, then interference resistance is improved, but transmission distance and signal-to-noise ratio deteriorate
Solution Approach 1:
The patent segments the communication signal across multiple frequency channels through frequency hopping, dividing the transmission into 1600 hops per second across 79 1-MHz channels. This segmentation allows the system to avoid interference on individual frequencies while maintaining overall communication reliability through diverse frequency paths.
Solution Approach 2:
The patent implements periodic frequency hopping at a rate of 1600 hops per second, creating regular temporal patterns in frequency switching. This periodic action across time and frequency domains enables the system to systematically navigate through potential interference zones while maintaining consistent signal-to-noise ratio performance.
2Reliability
If beamforming is implemented to improve transmission distance and signal-to-noise ratio, then transmission distance is improved, but device complexity increases due to multiple antennas requirement
Solution Approach 1:
The patent enables beamforming functionality in slave devices that traditionally have single antennas by making the slave device perform channel estimation and apply beamforming coefficients. This universal approach allows beamforming to work across different device configurations, with the master device's multiple antennas providing the spatial diversity needed for beamforming without requiring the slave device to have multiple antennas.
Solution Approach 2:
The patent uses the master device as an intermediary that provides channel estimation information to the slave device. The master device with its multiple antennas acts as a mediator that enables the slave device to perform beamforming operations without needing its own multiple antennas, thus reducing the complexity requirement for the slave device while still achieving beamforming benefits.
3Reliability
If implicit beamforming is supported in slave devices, then signal transmission is improved, but compatibility with master devices that do not support beamforming decreases
Solution Approach 1:
The patent inverts the traditional beamforming architecture by having the slave device (rather than the master device) perform the beamforming operations. The slave device estimates the channel based on received signals and applies beamforming coefficients to its transmissions. This inversion allows beamforming to work with master devices that do not natively support it, as the slave device independently performs the beamforming processing.
Solution Approach 2:
The slave device performs self-service by independently estimating the channel and calculating beamforming coefficients without requiring explicit beamforming support from the master device. The slave device uses the received training signals and data packets to autonomously determine channel conditions and apply appropriate beamforming, making the system compatible with legacy master devices while still achieving improved signal transmission.
Data Source
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AI summary
A wireless communication apparatus includes a channel estimation circuit, a beamforming control circuit, and a transmit (TX) circuit. The channel estimation circuit estimates a channel between the wireless communication apparatus and another wireless communication apparatus during at least one first time slot. The beamforming control circuit determines beamforming coefficients according to the estimated channel. The TX circuit applies the beamforming coefficients to transmission of an output data during at least one second time slot later than the at least one first time slot. During the at least one second time slot, the output data is transmitted to another wireless communication apparatus via multiple antennae. The wireless communication apparatus performs communications according to a normal frequency hopping sequence in compliance with a communication specification.