Constant Envelope Phase Modulation for BLE Audio Rate
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Solution Overview
Problem
Bluetooth Low Energy (BLE) audio technology is limited by its low maximum transmission rate, which restricts wireless audio quality, and reducing symbol duration to improve this rate increases bandwidth and multipath interference, while alternative modulations like DPSK and multi-carrier are not suitable for BLE RF transmitters.
Innovation Solution
Implementing constant envelope phase modulation (CEPM) and corresponding phase demodulation techniques to increase wireless transmission rate while maintaining a larger symbol duration, reducing multipath interference and improving transmission quality by converting binary data into phase symbols, modulating with a phase waveform, and converting the phase signal into baseband signals for RF transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the symbol duration of GFSK modulation is reduced to improve transmission rate, then the wireless transmission rate is improved, but the bandwidth occupied increases and multipath interference impact increases
Solution Approach 1:
The patent changes the modulation parameter from GFSK to constant envelope phase modulation (CEPM), which allows for longer symbol duration while maintaining high transmission rate. This parameter change resolves the contradiction by enabling the system to operate at higher rates without the harmful effects of reduced symbol duration.
2Productivity
If DPSK modulation or multi-carrier modulation is used to increase transmission rate, then the wireless transmission rate is improved, but the signal becomes incompatible with BLE RF transmitter constant envelope requirement
Solution Approach 1:
The patent applies local quality by maintaining the constant envelope property specifically at the RF transmitter output while using advanced phase modulation techniques. The CEPM modulation ensures that the envelope remains constant locally at the transmitter, satisfying BLE RF requirements, while still achieving high transmission rates through phase variations.
3Productivity
If GFSK modulation with short symbol duration is used, then transmission rate is improved, but long-range wireless transmission performance deteriorates
Solution Approach 1:
The patent changes the modulation scheme from GFSK to constant envelope phase modulation, which fundamentally alters the signal characteristics. This parameter change enables longer symbol durations that are more resilient to long-range transmission challenges while maintaining high data rates, thus improving both productivity and reliability simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The CEPM technique enhances wireless transmission rate and quality by reducing multipath interference, making the signal suitable for BLE RF transmitters and facilitating efficient demodulation, thereby improving long-range wireless audio transmission.
Implementation Method 1
modulating a phase sequence composed of the phase symbols into a phase signal using a phase waveform obtained by integrating a predetermined pulse function
Implementation Method 2
converting the phase signal into two baseband signals by means of a cosine function and a sine function respectively
Data Source
AI summary
Techniques for constant envelope phase modulation and demodulation of a wireless signal such as BLE are described. The method comprises: dividing a binary data stream to be transmitted into a plurality of groups of binary data according to a predetermined phase modulation mode, each group of binary data comprising a plurality of bits; mapping the binary data stream into a plurality of phase symbols, wherein each group of binary data is mapped into one phase symbol; modulating a phase sequence composed of the phase symbols into a phase signal using a phase waveform obtained by integrating a predetermined pulse function; and converting the phase signal into two baseband signals by means of a cosine function and a sine function respectively.