Design And Implementation Of Voice Transmission System Based On Bluetooth Low Energy

Bluetooth Low Energy(BLE)is a new kind of wireless network technology with ultra-low running and standby power consumption.The technology is mainly designed for low-cost,simple wireless personal area network(PAN)and wireless body area network(BAN).Currently,the BLE technology is still a lack of research and application in the field of voice transmission.Although BLE technology was not born for voice transmission,due to some technical advantages,BLE technology has a certain advantages in short-distance wireless voice monitoring and other application scenarios,such as wireless voice monitoring scene based on baby.This thesis takes CC2640 chip of TI company and BLE 4.1 version protocol stack as the platform,combines requirements of the system and characteristics to design and implement a BLE voice transmission system.The key points of the designed system are:firstly,a power optimization strategy based on the slave delay protocol,a power optimization strategy based on dynamic update connection interval,and a two-level mute detection algorithm are designed for optimizing the system power consumption;Secondly,the ADPCM coding algorithm is selected to compress the speech data through analyzing the commonly used speech coding algorithm in order to meet the system bandwidth requirements and reduce the system communication storage capacity;Thirdly,the voice transmission services and specifications based on GATT are designed in order to enable BLE technology to effectively serve the voice transmission service and enhance user experience.Performance test result indicates that the power consumption of transmitting is 20.30mW,the power consumption of being mute is 13.58m W,under ideal conditions,the maximum transmission distance is 98m,the maximum data packet loss rate is 0.1%,MOS is 3.6 score,more clear and smooth playback of speech.All the test results meet the design requirement.The system has a good application performance.