CN-121984817-A - Method and system for data transmission between iOS device and external device

Abstract

The invention discloses a data transmission method and a data transmission system between iOS equipment and external equipment. The data transmitting end frames the original data to be transmitted to generate a data frame, wherein the data frame comprises a synchronous head, a length field, a data segment, a check code and an ending symbol, an FSK modulation mode or an OOK modulation mode is selected to modulate the data frame according to the transmission rate and the anti-interference requirement to generate an Audio signal, the data transmitting end outputs the Audio signal through a USB Audio interface, the data receiving end receives the Audio signal through the USB Audio interface, demodulates the received Audio signal, decodes the data frame, and checks and analyzes the decoded data frame to obtain the original data. The standard and open USB Audio protocol of the iOS equipment can avoid the MFi authentication barrier, and realize the bidirectional data transmission with low cost, high reliability and easy development between the iOS equipment and the external equipment.

Inventors

• LUO DAMING
• HU YINGZHE

Assignees

• 珠海普林芯驰科技有限公司

Dates

Publication Date

20260505

Application Date

20260129

Claims (10)

1. 1. A data transmission method between an iOS device and an external device, comprising: The method comprises the steps that a data sending end frames original data to be transmitted to generate a data frame, wherein the data frame comprises a synchronous head, a length field, a data segment, a check code and an ending symbol; According to the transmission rate and the anti-interference requirement, selecting an FSK modulation mode or an OOK modulation mode to modulate the data frame, and generating an audio signal; the data transmitting end outputs the Audio signal through a USB Audio interface; the data receiving end receives the Audio signal through a USB Audio interface; demodulating the received audio signal, and decoding the data frame; And checking and analyzing the decoded data frame to obtain the original data.
2. 2. The method for data transmission between iOS device and external device according to claim 1, characterized in that in the FSK modulation scheme, two different frequencies are used to represent 0 and 1 of binary data, respectively, the difference between the two frequencies is greater than 1/12 of the sampling rate, and both frequencies are in the range of 2kHz-12 kHz.
3. 3. The method of data transmission between an iOS device and an external device according to claim 2, characterized in that in the FSK modulation scheme, the frequency representing 0 is 4kHz, the frequency representing 1 is 8kHz, and the duration of each bit is 1ms.
4. 4. A method of data transmission between an iOS device and an external device according to claim 3, characterized in that in the FSK modulation scheme, frequency distortion of the iOS device audio engine is cancelled by frequency adaptive calibration, and the decision threshold is adjusted based on the energy mean and standard differential state.
5. 5. The method for data transmission between an iOS device and an external device according to claim 1, wherein in the OOK modulation scheme, 0 and 1 of binary data are represented by specific magnitudes.
6. 6. The method for data transmission between an iOS device and an external device according to claim 5, wherein in the OOK modulation scheme, a median filtering and sliding window mean algorithm is used to process the sampled data.
7. 7. The method for data transmission between an iOS device and an external device according to claim 6, wherein in the OOK modulation scheme, a dynamic threshold is generated based on intra-frame amplitude distribution, and an auxiliary threshold decision is performed by edge detection.
8. 8. The method for data transmission between an iOS device and an external device according to claim 1, wherein the checking and parsing of the decoded data frame comprises an error control step of: performing forward error correction coding on the data segment; at a data receiving end, performing forward error correction decoding firstly, and then performing cyclic redundancy check; if the verification fails, an automatic retransmission mechanism is started.
9. 9. A data transmission system between an iOS device and an external device, characterized by being configured to implement the data transmission method between an iOS device and an external device according to any one of claims 1 to 8, comprising: The iOS equipment end processing module is used for modulating data to be transmitted into an Audio signal and outputting the Audio signal through the USB Audio interface; and the external equipment end processing module is used for receiving the Audio signal through the USB Audio interface and demodulating the original data.
10. 10. The iOS device to external device data transmission system according to claim 9, wherein the external device side processing module comprises a demodulation coprocessor which implements FSK and OOK demodulation algorithms in hardware logic.

Description

Method and system for data transmission between iOS device and external device Technical Field The present invention relates to the field of communications technologies, and in particular, to a method and a system for transmitting data between an iOS device and an external device. Background The data communication demands between iOS devices (e.g., iphones or ipads) and external accessories or proprietary devices have shown explosive growth. However, apple Inc. has implemented a strict MFi (Made for iPhone/iPad/iPod) certification program for third party accessories that transfer data over their dedicated physical interfaces (e.g., lightning or USB-C) in order to maintain iOS ecology security and profits. This solution has the inherent disadvantage that, on the one hand, the third party accessory manufacturer must pass the MFi certification and pay for the licensing costs for the MFi certification chips used in the product. Secondly, the development period and the complexity are long, a developer must use a specific chip which is authenticated, and follow a complex development flow, and the technical scheme of the development flow needs to be checked, so that the product marketing time is prolonged. Thirdly, the technical limit, the MFi protocol stack is closed, and the capability of manufacturers to realize highly customized communication protocols is limited. To circumvent MFi authentication barriers, the industry has tried various alternatives, but all suffer from some drawbacks: 1. the wireless connection scheme is that Bluetooth (including low-power Bluetooth BLE) has the problems of complex pairing process, limited transmission rate, unstable communication delay, higher power consumption and the like, wi-Fi direct connection requires complex network configuration, is not suitable for a point-to-point communication scene requiring quick plug and play, and has higher power consumption. 2. Traditional wired scheme, before iPhone 7, part of the accessory transmits data through 3.5mm earphone hole for audio modem (e.g. FSK, DTMF). This scheme is low in rate, susceptible to interference, and most critical is that the iOS devices currently typically cancel this interface, resulting in the scheme failing. Disclosure of Invention The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a data transmission method and a system between the iOS equipment and the external equipment, which skillfully utilizes the standard and open USB Audio protocol of the iOS equipment, can avoid the MFi authentication barrier, and realizes the bidirectional data transmission with low cost, high reliability and easy development between the iOS equipment and the external equipment. In one aspect, an embodiment of the present invention provides a method for transmitting data between an iOS device and an external device, including: The method comprises the steps that a data sending end frames original data to be transmitted to generate a data frame, wherein the data frame comprises a synchronous head, a length field, a data segment, a check code and an ending symbol; The method comprises the steps that a data sending end frames original data to be transmitted to generate a data frame, wherein the data frame comprises a synchronous head, a length field, a data segment, a check code and an ending symbol; According to the transmission rate and the anti-interference requirement, selecting an FSK modulation mode or an OOK modulation mode to modulate the data frame, and generating an audio signal; the data transmitting end outputs the Audio signal through a USB Audio interface; the data receiving end receives the Audio signal through a USB Audio interface; demodulating the received audio signal, and decoding the data frame; And checking and analyzing the decoded data frame to obtain the original data. According to some embodiments of the invention, in the FSK modulation scheme, two different frequencies are used to represent 0 and 1 of binary data, respectively, the difference between the two frequencies is greater than 1/12 of the sampling rate, and both frequencies are in the range of 2kHz-12 kHz. According to some embodiments of the invention, in the FSK modulation scheme, the frequency representing 0 is 4kHz, the frequency representing 1 is 8kHz, and the duration of each bit is 1ms. According to some embodiments of the invention, in the FSK modulation scheme, frequency distortion of the iOS device audio engine is cancelled by frequency adaptive calibration, and a decision threshold is adjusted based on an energy mean and a standard differential state. According to some embodiments of the invention, in the OOK modulation scheme, specific magnitudes are used to represent 0 and 1 of binary data. According to some embodiments of the invention, in the OOK modulation scheme, a median filtering and sliding window mean algorithm is used to process the sampled data. A