A cross-technology data transmission method and system from Wi-Fi to LoRa

Abstract

This invention provides a cross-technology data transmission method and system from Wi-Fi to LoRa. The method includes the following steps: obtaining the phase of a LoRa analog signal based on the Wi-Fi data to be transmitted, and constructing an effective signal based on the phase and a preset amplitude; performing a Fast Fourier Transform on the effective signal to obtain a frequency domain signal, and using vector decomposition to obtain the orthogonal and in-phase components of the frequency domain signal, constructing corresponding points in a preset orthogonal amplitude modulation constellation diagram; obtaining the constellation point closest to the corresponding point, obtaining the coded bit sequence corresponding to the constellation point, and obtaining the source bit sequence based on the coded bit sequence; filtering transmission resource units from multiple resource units based on the bandwidth of the resource unit; aggregating multiple Wi-Fi subframes to obtain a protocol data unit, mapping the protocol data unit to the source bit sequence, and constructing a Wi-Fi data packet; encoding the Wi-Fi data packet to obtain a Wi-Fi physical layer data frame; and demodulating and decoding the Wi-Fi physical layer data frame at the LoRa end to obtain a LoRa data packet, thus completing the data transmission.

Description

Technical Field

[0001] The present invention relates to the field of cross-technology communication technology, and in particular to a cross-technology data transmission method and system from Wi-Fi to LoRa. Background Art

[0002] The Internet of Things (IoT) technology depicts a grand vision of the future of the Internet of Everything. Any independently addressable object can be integrated into people's lives through network interconnection, providing people with intelligent and convenient services. IoT technology has received more and more attention in the application field. The development of IoT technology (IoT) has promoted the richness and diversity of wireless technologies, such as Wi-Fi, ZigBee, Long Range Radio (LoRa), etc. With the rapid popularization of IoT applications, different types of wireless networks are constantly expanding their application spaces, gradually forming a state where multiple networks and multiple protocols coexist in the same space. Diverse wireless network protocols not only need to maintain their own effective operation and interconnection in the coexistence environment, but also often need to realize cross-network and cross-technology communication, and carry out necessary data exchange and information sharing. However, the existing wireless network protocols cannot share data information with each other. Therefore, the problem of coexistence of wireless network protocols arises.

[0003] There have been many studies on the realization of cross-technology communication (CTC) between Wi-Fi, Bluetooth and ZigBee. Cross-technology communication at the packet layer is to achieve information exchange between heterogeneous devices by modulating the transmission time, signal strength and channel state information of the packet. WiZig uses multiple energy levels to encode multiple bits at the same time, transmits different cross-technology information by modulating the power of different transmission signals, and uses Manchester Coding and interference cancellation technology to achieve interference-resistant CTC communication.

[0004] With the development of 2.4GHz LoRa, cross-technology communication between LoRa and other technologies has also attracted the attention of more and more researchers. Due to the Internet accessibility of Wi-Fi, interconnecting Wi-Fi and LoRa has also attracted the interest of researchers. XFI is an inter-chip electrical interface specification. XFI uses Wi-Fi devices to implement uplink reception of LoRa data and uses Wi-Fi access points (APs) as LoRa gateways. When using Wi-Fi as a LoRa gateway, a downlink from Wi-Fi to LoRa also needs to be established.

[0005] Wi-Lo is the only cross-technology communication that implements the downlink from Wi-Fi to LoRa. Wi-Lo uses the waveform similarity between LoRa linear frequency modulation spread spectrum (CSS) and the wireless LAN standard IEEE 802.11b to simulate LoRa. However, Wi-Lo does not fully consider the extremely asymmetric data rate between Wi-Fi and LoRa, and uses the 802.11b Wi-Fi signal of the entire frequency band to simulate the LoRa signal. Therefore, there is a serious problem of low spectrum efficiency, which leads to a decrease in transmission efficiency. Summary of the invention

[0006] In view of this, an embodiment of the present invention provides a cross-technology data transmission method and system from Wi-Fi to LoRa to eliminate or improve one or more defects in the prior art.

[0007] One aspect of the present invention provides a cross-technology data transmission method from Wi-Fi to LoRa, wherein the Wi-Fi end is preset with multiple resource units, and the method comprises the following steps:

[0008] Obtain Wi-Fi data to be transmitted, obtain the phase of the LoRa analog signal to be simulated based on the Wi-Fi data to be transmitted, and construct a valid signal according to the phase of the LoRa analog signal and the amplitude of the preset LoRa analog signal;

[0009] Performing a fast Fourier transform on the effective signal to obtain a frequency domain signal, performing vector decomposition on the frequency domain signal to obtain an orthogonal component and an in-phase component of the frequency domain signal, and constructing corresponding points in a preset orthogonal amplitude modulation constellation diagram according to the orthogonal component and the in-phase component;

[0010] There are multiple constellation points in the orthogonal amplitude modulation constellation diagram, obtaining the constellation point closest to the corresponding point, obtaining the coded bit sequence corresponding to the constellation point, and obtaining the source bit sequence according to the coded bit sequence;

[0011] Selecting a transmission resource unit from a plurality of preset resource units based on the bandwidth of the resource unit;

[0012] Aggregating multiple Wi-Fi subframes in the Wi-Fi data to be transmitted to obtain a protocol data unit, and mapping the protocol data unit to a source bit sequence in the transmission resource unit to construct a first Wi-Fi data packet;

[0013] Transmitting the first Wi-Fi data packet to the physical layer of the Wi-Fi end for encoding to obtain a second Wi-Fi data packet;

[0014] The second Wi-Fi data packet is transmitted from the Wi-Fi end to the LoRa end, and the second Wi-Fi data packet is demodulated and decoded at the LoRa end to obtain a LoRa data packet, thereby completing data transmission.

[0015] In the cross-technology data transmission method from Wi-Fi to LoRa of the present invention, since the IEEE 802.11ax protocol adopts orthogonal frequency domain multiple access (OFDMA), the available spectrum is divided into resource units (RU) of various sizes to achieve simultaneous transmission of multiple users. In the present application, the Wi-Fi end allocates an RU for communicating with the LoRa end, and only maps the simulated LoRa waveform on the RU instead of simulating the LoRa waveform on the entire spectrum. Therefore, the Wi-Fi end can still use other resource units to perform high-speed Wi-Fi data transmission, thereby improving transmission efficiency.

[0016] In some embodiments of the present invention, the step of transmitting the first Wi-Fi data packet to the physical layer of the Wi-Fi end for encoding further includes adding a physical layer header to the data frame in the first Wi-Fi data packet so that the data frame of the second Wi-Fi data packet constitutes a physical layer data frame.

[0017] In some embodiments of the present invention, the step of obtaining a LoRa data packet further includes deleting a physical layer header in the physical layer data frame.

[0018] In some implementations of the present invention, a source bit sequence is obtained according to the coded bit sequence and calculated according to the following formula:

[0019]

[0020] X represents the source bit sequence, represents a sub-matrix of the interleaved coding matrix, represents a submatrix of the convolutional coding matrix, Represents a coded bit sequence.

[0021] In some implementations of the present invention, the step of screening the transmission resource unit from the preset multiple resource units based on the bandwidth of the resource unit further includes:

[0022] Calculating a minimum number of subcarriers included in the resource unit based on the bandwidth of the resource unit;

[0023] Based on the minimum number of subcarriers, a submatrix of the interleaving coding matrix and a submatrix of the convolutional coding matrix are calculated, and whether the resource unit meets the preset screening conditions is determined according to the submatrix of the interleaving coding matrix and the submatrix of the convolutional coding matrix, and the resource unit that meets the screening conditions is output.

[0024] In some implementations of the present invention, the minimum number of subcarriers of the resource unit is calculated based on the bandwidth of the resource unit, and is calculated according to the following formula:

[0025]

[0026] BW represents the bandwidth of the resource unit, s represents the minimum number of subcarriers of the resource unit with a bandwidth of BW, and 78.125 represents the size of a single subcarrier in Khz.

[0027] In some embodiments of the present invention, a submatrix of an interleaved coding matrix and a submatrix of a convolutional coding matrix are calculated based on the minimum number of subcarriers, and are calculated according to the following formula:

[0028]

[0029]

[0030] represents a sub-matrix of the interleaved coding matrix, represents the submatrix of the convolutional coding matrix, K is the number of constellation points of the orthogonal amplitude modulation constellation diagram, c is the coding rate, s represents the minimum number of subcarriers of the resource unit with bandwidth BW, and m is the actual number of subcarriers of the resource unit.

[0031] In some embodiments of the present invention, whether the resource unit meets the preset screening conditions is judged according to the sub-matrix of the interleaved coding matrix and the sub-matrix of the convolutional coding matrix, and the screening conditions are (s·log2K)≤(m·log2K·c), K is the number of constellation points of the orthogonal amplitude modulation constellation diagram, c is the coding rate, s represents the number of subcarriers, and m is the actual number of subcarriers of the resource unit.

[0032] In some implementations of the present invention, the step of outputting resource units that meet the screening conditions further includes extracting a resource unit with the smallest bandwidth from the resource units that meet the screening conditions as a transmission resource unit.

[0033] In some embodiments of the present invention, a plurality of Wi-Fi subframes are aggregated in the transmission resource unit, the Wi-Fi subframe includes a subframe header and a subframe payload, the source bit sequence includes a synchronization word, a start frame delimiter, and a preamble, and the step of mapping the protocol data unit to the source bit sequence in the transmission resource unit includes:

[0034] When the length of the subframe payload of a single Wi-Fi subframe is capable of mapping 2 synchronization words and 2.25 start frame delimiters, the 2 synchronization words and 2.25 start frame delimiters are mapped into the subframe payload of the single Wi-Fi subframe;

[0035] When the position of the subframe header of the Wi-Fi subframe corresponds to the preamble, the subframe header of the Wi-Fi subframe is mapped to the end of the corresponding preamble symbol.

[0036] In some embodiments of the present invention, the step of mapping the protocol data unit to a source bit sequence in the transmission resource unit further includes:

[0037] When the length of the subframe payload of a single Wi-Fi subframe cannot map 2 synchronization words and 2.25 start frame delimiters, if the subframe payload can accommodate 2 synchronization words, the 2 synchronization words are mapped into the subframe payload of the single Wi-Fi subframe.

[0038] In some embodiments of the present invention, the source bit sequence further includes a LoRa payload, and the step of mapping the protocol data unit to the source bit sequence in the transmission resource unit further includes:

[0039] If the subframe header is mapped to a LoRa payload, a mode symbol is marked at the position of the LoRa payload;

[0040] If there is a LoRa payload with the same symbol as the pattern symbol in the LoRa payload, the pattern symbol is marked before the LoRa payload.

[0041] The cross-technology data transmission method from Wi-Fi to LoRa of the present invention, since the IEEE 802.11ax protocol adopts orthogonal frequency domain multiple access (OFDMA), the available spectrum is divided into resource units (RU) of various sizes to achieve simultaneous transmission of multiple users. In the present application, the Wi-Fi end allocates an RU for communicating with the LoRa end, and simulates the LoRa waveform only on the RU instead of on the entire spectrum. Therefore, the Wi-Fi end can still use other resource units for high-speed Wi-Fi data transmission, thereby improving transmission efficiency.

[0042] Additional advantages, purposes, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention can be specifically pointed out and obtained in the specification and the accompanying drawings.

[0043] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention.

[0045] Figure 1 A schematic diagram of an implementation of a cross-technology data transmission method from Wi-Fi to LoRa of the present invention;

[0046] Figure 2 A schematic diagram of a first implementation method of mapping the protocol data unit to a source bit sequence;

[0047] Figure 3 A schematic diagram of a second implementation method of mapping the protocol data unit to a source bit sequence;

[0048] Figure 4 A schematic diagram for constructing corresponding points in a preset quadrature amplitude modulation constellation diagram;

[0049] Figure 5 is a schematic diagram of a quadrature amplitude modulation constellation diagram;

[0050] Figure 6 A schematic diagram showing the effect of subframe header mapping on bit error rate and packet reception rate;

[0051] Figure 7 A schematic diagram of a third implementation method of mapping the protocol data unit to a source bit sequence;

[0052] Figure 8 A schematic diagram of a fourth implementation method of mapping the protocol data unit to a source bit sequence;

[0053] Fig. 9 It is a schematic diagram of a fifth implementation method of mapping the protocol data unit to a source bit sequence. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0055] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0056] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0057] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0058] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0059] Wi-Lo is the only cross-technology communication work that realizes the downlink from Wi-Fi to LoRa. Wi-Lo uses the waveform similarity between LoRa CSS and IEEE 802.11b to simulate LoRa. The specific algorithm of Wi-Lo is as follows:

[0060] Generate a LoRa baseband signal S with a sampling rate of 11MHz, and divide the signal S into blocks with a time length of 8 / 11μs;

[0061] For each block of signal S, a closest complementary code keying (CCK) symbol needs to be found.

[0062] By performing the inverse process of complementary code keying modulation, the corresponding Wi-Fi payload P is calculated from the CCK symbol. The Wi-Fi transmitter transmits the payload P in a standard Wi-Fi packet, and the LoRa receiver can successfully decode the cross-technology data packet.

[0063] However, Wi-Lo does not fully consider the extremely asymmetric data rates between Wi-Fi and LoRa, and uses the 802.11b Wi-Fi signal of the entire frequency band to simulate the LoRa signal, so there is a serious problem of spectrum inefficiency. In order to achieve LoRa with a bandwidth of several hundred Hz and a data rate of tens of kbps, stopping the downlink traffic being transmitted by all high-speed Wi-Fi users will seriously reduce the spectrum utilization. Therefore, the LoRa frame simulated by the existing technology may occupy a channel for tens or even hundreds of milliseconds, resulting in a large amount of overhead that offsets the benefits of CTC.

[0064] The Wi-Fi end of this application can allocate an RU that overlaps with the LoRa channel and simulate the LoRa waveform only on the small RU instead of on the entire spectrum. In this way, Wi-Fi users can still use other 802.11ax resource units for high-speed Wi-Fi data transmission, improving transmission efficiency.

[0065] like Figure 1 , 4 As shown, one aspect of the present invention provides a cross-technology data transmission method from Wi-Fi to LoRa, wherein the Wi-Fi end is preset with multiple resource units, and the method comprises the following steps:

[0066] In some implementations of the present invention, the Wi-Fi end adopts the IEEE 802.11ax protocol, and there are multiple resource units in the IEEE 802.11ax protocol.

[0067] Step S100: obtaining Wi-Fi data to be transmitted, obtaining the phase of a LoRa analog signal to be simulated based on the Wi-Fi data to be transmitted, and constructing a valid signal according to the phase of the LoRa analog signal and a preset amplitude of the LoRa analog signal; Figure 4 The Desired Signals in are valid signals.

[0068] In some embodiments of the present invention, the corresponding relationship between the phase of the Wi-Fi data and the LoRa analog signal is shown in Table 1 and Table 2 below:

[0069] Table 1

[0070]

[0071]

[0072] Table 2

[0073]

[0074]

[0075] The phase of the LoRa analog signal is composed of multiple phase points, which are 64 symbols in Table 1 or 128 symbols in Table 2.

[0076] In some embodiments of the present invention, the amplitude may be set to 0.5, 1 or 1.5.

[0077] like Figure 1 , 4 As shown, step S200, performing fast Fourier transform on the effective signal to obtain a frequency domain signal, performing vector decomposition on the frequency domain signal to obtain an orthogonal component and an in-phase component of the frequency domain signal, and constructing corresponding points in a preset orthogonal amplitude modulation constellation diagram according to the orthogonal component and the in-phase component;

[0078] In some embodiments of the present invention, the quadrature amplitude modulation (Quadrature Amplitude Modulation, QAM) constellation diagram can be 16QAM, 64QAM or 256QAM, 16QAM is set with 16 constellation points, 64QAM is set with 64 constellation points or 256QAM is set with 256 constellation points.

[0079] like Figure 1 ,4 As shown, step S300, there are multiple constellation points in the orthogonal amplitude modulation constellation diagram, obtain the constellation point closest to the corresponding point, obtain the coded bit sequence corresponding to the constellation point, and obtain the source bit sequence according to the coded bit sequence;

[0080] Figure 4 The Quantization module is used to find the constellation point closest to the corresponding point in the orthogonal amplitude modulation constellation diagram; Figure 4 In FFT, it means Fast Fourier Transform; Figure 4 QAM points represent constellation points.

[0081] In some embodiments of the present invention, the horizontal axis of the orthogonal amplitude modulation constellation diagram represents the in-phase component, and the vertical axis represents the orthogonal component. According to the orthogonal component and the in-phase component of the frequency domain signal, a corresponding point is constructed in the orthogonal amplitude modulation constellation diagram, and the distance between the corresponding point and each constellation point is calculated to obtain the constellation point closest to the corresponding point.

[0082] like Figure 5 As shown, Figure 5 The numbers above the constellation points represent the coded bit sequences corresponding to the constellation points. In some embodiments of the present invention, coded bit sequences are set corresponding to the constellation points in the orthogonal amplitude modulation constellation diagram, and the coded bit sequence of the constellation point closest to the corresponding point is obtained.

[0083] like Figure 1 As shown, step S400, screening transmission resource units from a plurality of preset resource units based on the bandwidth of the resource units;

[0084] In some embodiments of the present invention, the IEEE 802.11ax protocol uses Orthogonal Frequency Domain Multiple Access (OFDMA) to divide the available spectrum into Resource Units (RUs) of various bandwidths to achieve simultaneous transmission of multiple users.

[0085] like Figure 1 As shown, step S500, a plurality of Wi-Fi subframes in the Wi-Fi data to be transmitted are aggregated to obtain a protocol data unit, and the protocol data unit is mapped to a source bit sequence in the transmission resource unit to construct a first Wi-Fi data packet;

[0086] like Figure 1 , 2 As shown in , 3, in some embodiments of the present invention, since the length of the source bit sequence is greater than a single Wi-Fi subframe, multiple Wi-Fi subframes are aggregated into a protocol data unit equal to the length of the source bit sequence to facilitate corresponding mapping.

[0087] like Figure 1 As shown, step S600, transmitting the first Wi-Fi data packet to the physical layer of the Wi-Fi end for encoding to obtain a second Wi-Fi data packet;

[0088] The encoding method may be 64-QAM 3 / 4;

[0089] like Figure 1 As shown, in step S700, the second Wi-Fi data packet is transmitted from the Wi-Fi end to the LoRa end, and the second Wi-Fi data packet is demodulated and decoded at the LoRa end to obtain a LoRa data packet, thereby completing data transmission.

[0090] In some embodiments of the present invention, the demodulation and decoding processing of the LoRa end is implemented by linear spread spectrum (Chirp Spread Spectrum, CSS).

[0091] The cross-technology data transmission method from Wi-Fi to LoRa of the present invention, since the IEEE 802.11ax protocol adopts orthogonal frequency domain multiple access (OFDMA), the available spectrum is divided into resource units (RU) of various sizes to achieve simultaneous transmission of multiple users. In the present application, the Wi-Fi end allocates an RU for communicating with the LoRa end, and simulates the LoRa waveform only on the RU instead of on the entire spectrum. Therefore, the Wi-Fi end can still use other resource units for high-speed Wi-Fi data transmission, thereby improving transmission efficiency.

[0092] In some embodiments of the present invention, the step of transmitting the first Wi-Fi data packet to the physical layer of the Wi-Fi end for encoding further includes adding a physical layer header to the data frame in the first Wi-Fi data packet so that the data frame of the second Wi-Fi data packet constitutes a physical layer data frame.

[0093] In some embodiments of the present invention, the step of obtaining a LoRa data packet further includes deleting a physical layer header in the physical layer data frame.

[0094] In some implementations of the present invention, a source bit sequence is obtained according to the coded bit sequence and calculated according to the following formula:

[0095]

[0096] X represents the source bit sequence, represents a sub-matrix of the interleaved coding matrix, represents a submatrix of the convolutional coding matrix, Represents a coded bit sequence.

[0097] Using the above solution, and All are matrices, calculated by By taking the inverse of , we can calculate X.

[0098] In some embodiments of the present invention, the Wi-Fi encoding process may be expressed as Y=(IG)Y, where X represents a source bit sequence, Y represents a Wi-Fi encoding bit sequence, I represents an interleaving encoding matrix, and G represents a convolutional encoding matrix;

[0099] Since the size of RU is not equal to the LoRa bandwidth, the coded bit corresponding to the LoRa signal is only a subvector of Y but in and are the sub-matrices of I and G respectively.

[0100] In some implementations of the present invention, the step of screening the transmission resource unit from the preset multiple resource units based on the bandwidth of the resource unit further includes:

[0101] Calculating a minimum number of subcarriers included in the resource unit based on the bandwidth of the resource unit;

[0102] Based on the minimum number of subcarriers, a submatrix of the interleaving coding matrix and a submatrix of the convolutional coding matrix are calculated, and whether the resource unit meets the preset screening conditions is determined according to the submatrix of the interleaving coding matrix and the submatrix of the convolutional coding matrix, and the resource unit that meets the screening conditions is output.

[0103] In some implementations of the present invention, the minimum number of subcarriers of the resource unit is calculated based on the bandwidth of the resource unit, and is calculated according to the following formula:

[0104]

[0105] BW represents the bandwidth of the resource unit, s represents the minimum number of subcarriers of the resource unit with a bandwidth of BW, and 78.125 represents the size of a single subcarrier in Khz.

[0106] In some embodiments of the present invention, the transmission resource unit is screened from a plurality of preset resource units based on the bandwidth of the resource unit, and the resource unit with the smallest bandwidth satisfying m≥s is screened out as the transmission resource unit, where m is the actual number of subcarriers in the resource unit.

[0107] By adopting the above solution and using RU with the smallest possible bandwidth, more spectrum resources can be saved.

[0108] In some embodiments of the present invention, a submatrix of an interleaved coding matrix and a submatrix of a convolutional coding matrix are calculated based on the minimum number of subcarriers, and are calculated according to the following formula:

[0109]

[0110]

[0111] represents a sub-matrix of the interleaved coding matrix, represents the submatrix of the convolutional coding matrix, K is the number of constellation points of the orthogonal amplitude modulation constellation diagram, c is the coding rate, s represents the number of subcarriers, and m is the actual number of subcarriers of the resource unit.

[0112] In some embodiments of the present invention, whether a resource unit meets a preset screening condition is determined based on a sub-matrix of an interleaved coding matrix and a sub-matrix of a convolutional coding matrix, and the screening condition is (s·log2K)≤(m·log2K·c).

[0113] In some embodiments of the present invention, the screening condition is

[0114] Using the above solution, for the formula By calculation We can calculate X by the inverse of Need to be calculated by Gaussian elimination, so only is full rank or a square matrix, It can be calculated through Gaussian elimination. Compared with directly using the RU with the smallest bandwidth, this solution ensures that the number of subcarriers m contained in the RU is greater than s, and has higher calculation efficiency.

[0115] In some implementations of the present invention, the step of outputting resource units that meet the screening conditions is to extract resource units with the smallest bandwidth from the resource units that meet the screening conditions as transmission resource units.

[0116] like Figure 2 , 3 As shown, in some embodiments of the present invention, the Wi-Fi subframe includes a subframe header, and the step of aggregating multiple Wi-Fi subframes in the Wi-Fi data to be transmitted to obtain a protocol data unit includes connecting the multiple Wi-Fi subframes end to end, and the total length of the multiple Wi-Fi subframes minus the subframe header length of the first Wi-Fi subframe = the protocol data unit length = the length of the source bit sequence.

[0117] Figure 2 , 3Where preamble indicates preamble, Sync word indicates synchronization word, SFD indicates start frame delimiter, Subframe header indicates subframe header, Pattern symbol indicates pattern symbol, MPDU indicates Wi-Fi subframe, and Mappingerror indicates mapping error.

[0118] Figure 2 The payload in the MPDU represents the LoRa payload, and the payload away from the MPDU represents the subframe payload of the Wi-Fi subframe.

[0119] Using the above solution, if Figure 6 As shown, Figure 6 The horizontal axis is the LoRa signal duration. The mapping of the subframe header affects the Wi-Fi data packet. Figure 6 As shown in (a), the bit error rate (Symbol Error Rate, SER) and Figure 6 (b) shows the packet reception ratio (PRR), which reduces the number of mapped subframe headers and improves the bit error rate and packet reception rate. On the other hand, the protocol data unit length is made equal to the length of the source bit sequence, which facilitates the mapping of the protocol data unit and the source bit sequence according to the corresponding symbol positions.

[0120] like Figure 2 As shown, in some embodiments of the present invention, a plurality of Wi-Fi subframes are aggregated in the transmission resource unit, the Wi-Fi subframe includes a subframe header and a subframe payload, the source bit sequence includes a synchronization word, a start frame delimiter, and a preamble, and the step of mapping the protocol data unit to the source bit sequence in the transmission resource unit includes:

[0121] When the length of the subframe payload of a single Wi-Fi subframe is capable of mapping 2 synchronization words and 2.25 start frame delimiters, the 2 synchronization words and 2.25 start frame delimiters are mapped into the subframe payload of the single Wi-Fi subframe;

[0122] When the position of the subframe header of the Wi-Fi subframe corresponds to the preamble, the subframe header of the Wi-Fi subframe is mapped to the end of the corresponding preamble.

[0123] With the above scheme, the simulation of the synchronization word and the start frame delimiter (SFD) is more susceptible to the damage of the subframe header compared with the preamble, avoiding mapping the Wi-Fi subframe header to the LoRa synchronization word and SFD symbol, and improving the accuracy of Wi-Fi data packet transmission.

[0124] like Figure 3As shown, in some embodiments of the present invention, the step of mapping the protocol data unit to a source bit sequence in the transmission resource unit further includes:

[0125] When the length of the subframe payload of a single Wi-Fi subframe cannot map 2 synchronization words and 2.25 start frame delimiters, if the subframe payload can accommodate 2 synchronization words, the 2 synchronization words are mapped into the subframe payload of the single Wi-Fi subframe.

[0126] With the above solution, the first simulated SFD symbol will be affected by the Wi-Fi subframe header, but the duration of SFD is 2.25*1024=2304μs, and the duration of a Wi-Fi subframe header is only 40.3μs. Therefore, the impact caused by the distortion can be ignored. In this case, the SFD symbol distortion caused can be tolerated by SFD detection, reducing the impact of the subframe header.

[0127] like Figure 2 , 7 As shown in , 8, in some embodiments of the present invention, the source bit sequence also includes a LoRa payload, and the step of mapping the protocol data unit to the source bit sequence in the transmission resource unit also includes:

[0128] If the subframe header is mapped to a LoRa payload, a mode symbol is marked at the position of the LoRa payload;

[0129] If there is a LoRa payload with the same symbol as the pattern symbol in the LoRa payload, the pattern symbol is marked before the LoRa payload.

[0130] With the above solution, the position of the mode symbol corresponds to the position of the subframe header, and the mode symbol can play a role in indicating the subframe header, thereby preventing recognition errors caused by the subframe header.

[0131] In some embodiments of the present invention, if the mode symbol is "00" and the LoRa payload is "00", "00" is added before the LoRa payload "00".

[0132] like Fig. 9 As shown, in some embodiments of the present invention, the step of mapping the protocol data unit to a source bit sequence in the transmission resource unit further includes:

[0133] If there are at least two consecutive LoRa payloads in the LoRa payload whose symbol is the same as the mode symbol, the mode symbol is marked at the position before the at least two consecutive LoRa payloads.

[0134] In some embodiments of the present invention, if two consecutive LoRa payloads are "00" and "1" respectively, the two constitute "001". If the mode symbol is "001", "001" is added before the two consecutive LoRa payloads "001".

[0135] With the above scheme, when the normal LoRa payload has the same symbol as the pattern symbol, we will add the pattern symbol before the payload symbol to avoid confusion, and we can still keep this payload symbol when removing the pattern symbol during the decoding process.

[0136] In some embodiments of the present invention, the step after obtaining the LoRa data packet also includes deleting the mode symbol in the LoRa data packet.

[0137] In some embodiments of the present invention, after obtaining the LoRa data packet, the method further includes a step of parsing the LoRa data packet, and the packet parsing step includes deleting the mode symbol, physical layer header, synchronization word and start frame delimiter in the LoRa data packet.

[0138] In some embodiments of the present invention, the mode symbol, physical layer header, synchronization word and start frame delimiter in the LoRa data packet are deleted to finally obtain the payload part of the LoRa data packet, and the payload of the LoRa data packet is used to load the data actually required to be transmitted.

[0139] In some embodiments of the present invention, the step of deleting the pattern symbol in the LoRa data packet is to restore the demodulated symbol sequence of the LoRa data packet through the inverse process of LoRa decoding, and then traverse all the demodulated symbols in the symbol sequence that have the same value as the pattern symbol. These symbols are considered to be invalid symbols caused by Wi-Fi subframe header errors, and delete the above demodulated symbols that have the same value as the pattern symbol.

[0140] In some embodiments of the present invention, the step of demodulating and decoding the second Wi-Fi data packet at the LoRa end includes:

[0141] Detecting the preamble in the second Wi-Fi data packet and performing coarse-grained synchronization;

[0142] Detecting the synchronization word and the start frame delimiter in the second Wi-Fi data packet to perform fine-grained synchronization;

[0143] The positions of the preamble, sync word, and start frame delimiter are found through coarse-grained synchronization and fine-grained synchronization.

[0144] In some embodiments of the present invention, due to the structure of the protocol data unit (A-MPDU), the Wi-Fi subframe header will appear at equal time intervals, and its periodicity can be used to further improve the recognition accuracy of the pattern symbols. After the pattern symbols are recognized, they are removed to restore the LoRa frame.

[0145] In the cross-technology data transmission method from Wi-Fi to LoRa of the present invention, since the IEEE 802.11ax protocol adopts orthogonal frequency domain multiple access (OFDMA), the available spectrum is divided into resource units (RU) of various sizes to achieve simultaneous transmission of multiple users. In the present application, the Wi-Fi end allocates an RU for communicating with the LoRa end, and only maps the simulated LoRa waveform on the RU instead of simulating the LoRa waveform on the entire spectrum. Therefore, the Wi-Fi end can still use other resource units to perform high-speed Wi-Fi data transmission, thereby improving transmission efficiency.

[0146] Corresponding to the above-mentioned cross-technology data transmission method from Wi-Fi to LoRa, the present invention also provides a cross-technology data transmission system from Wi-Fi to LoRa, the system comprising a computer device, the computer device comprising a processor and a memory, the memory storing computer instructions, the processor being used to execute the computer instructions stored in the memory, and when the computer instructions are executed by the processor, the device / system implements the steps of the method described above.

[0147] The embodiment of the present invention also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the aforementioned cross-technology data transmission method from Wi-Fi to LoRa are implemented. The computer-readable storage medium can be a tangible storage medium, such as a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a floppy disk, a hard disk, a removable storage disk, a CD-ROM, or any other form of storage medium known in the technical field.

[0148] It should be understood by those skilled in the art that the exemplary components, systems and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software or a combination of the two. Whether it is performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link via a data signal carried in a carrier.

[0149] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0150] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0151] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cross-technology data transmission method from Wi-Fi to LoRa, characterized in that: The Wi-Fi end is preset with multiple resource units, and the method includes the following steps: Obtain Wi-Fi data to be transmitted, obtain the phase of the LoRa analog signal to be simulated based on the Wi-Fi data to be transmitted, and construct a valid signal according to the phase of the LoRa analog signal and the amplitude of the preset LoRa analog signal; Performing a fast Fourier transform on the effective signal to obtain a frequency domain signal, performing vector decomposition on the frequency domain signal to obtain an orthogonal component and an in-phase component of the frequency domain signal, and constructing corresponding points in a preset orthogonal amplitude modulation constellation diagram according to the orthogonal component and the in-phase component; There are multiple constellation points in the orthogonal amplitude modulation constellation diagram, obtaining the constellation point closest to the corresponding point, obtaining the coded bit sequence corresponding to the constellation point, and obtaining the source bit sequence according to the coded bit sequence; A transmission resource unit is screened from a plurality of preset resource units based on the bandwidth of the resource unit, and a minimum number of subcarriers included in the resource unit is calculated based on the bandwidth of the resource unit; a submatrix of an interleaving coding matrix and a submatrix of a convolutional coding matrix are calculated based on the minimum number of subcarriers, and whether the resource unit meets a preset screening condition is determined according to the submatrix of the interleaving coding matrix and the submatrix of the convolutional coding matrix, and a resource unit meeting the screening condition is output, and a minimum number of subcarriers of the resource unit is calculated based on the bandwidth of the resource unit, and the calculation is performed according to the following formula: BW represents the bandwidth of the resource unit, s represents the minimum number of subcarriers of the resource unit with a bandwidth of BW, and 78.125 represents the size of a single subcarrier in Khz; Aggregating multiple Wi-Fi subframes in the Wi-Fi data to be transmitted to obtain a protocol data unit, and mapping the protocol data unit to a source bit sequence in the transmission resource unit to construct a first Wi-Fi data packet; Transmitting the first Wi-Fi data packet to the physical layer of the Wi-Fi end for encoding to obtain a second Wi-Fi data packet; The second Wi-Fi data packet is transmitted from the Wi-Fi end to the LoRa end, and the second Wi-Fi data packet is demodulated and decoded at the LoRa end to obtain a LoRa data packet, thereby completing data transmission.

2. The method according to claim 1, characterized in that The source bit sequence is obtained according to the coded bit sequence and calculated according to the following formula: X represents the source bit sequence, represents a sub-matrix of the interleaved coding matrix, represents a submatrix of the convolutional coding matrix, Represents a coded bit sequence.

3. The method according to claim 1, characterized in that The sub-matrix of the interleaved coding matrix and the sub-matrix of the convolutional coding matrix are calculated based on the minimum number of subcarriers, and are calculated according to the following formula: represents a sub-matrix of the interleaved coding matrix, represents the submatrix of the convolutional coding matrix, K is the number of constellation points of the orthogonal amplitude modulation constellation diagram, c is the coding rate, s represents the minimum number of subcarriers of the resource unit with bandwidth BW, and m is the actual number of subcarriers of the resource unit.

4. The method according to claim 3, characterized in that Whether the resource unit meets the preset screening conditions is determined according to the sub-matrix of the interleaved coding matrix and the sub-matrix of the convolutional coding matrix, and the screening conditions are (s·log2K)≤(m·log2K·c), K is the number of constellation points of the orthogonal amplitude modulation constellation diagram, c is the coding rate, s represents the number of subcarriers, and m is the actual number of subcarriers of the resource unit.

5. The method according to any one of claims 1 to 4, characterized in that The transmission resource unit includes a plurality of Wi-Fi subframes, the Wi-Fi subframes include a subframe header and a subframe payload, the source bit sequence includes a synchronization word, a start frame delimiter, and a preamble, and the step of mapping the protocol data unit to the source bit sequence in the transmission resource unit includes: When the length of the subframe payload of a single Wi-Fi subframe is capable of mapping 2 synchronization words and 2.25 start frame delimiters, the 2 synchronization words and 2.25 start frame delimiters are mapped into the subframe payload of the single Wi-Fi subframe; When the position of the subframe header of the Wi-Fi subframe corresponds to the preamble, the subframe header of the Wi-Fi subframe is mapped to the end of the corresponding preamble symbol.

6. The method according to claim 5, characterized in that The step of mapping the protocol data unit to a source bit sequence in the transmission resource unit also includes: When the length of the subframe payload of a single Wi-Fi subframe cannot map 2 synchronization words and 2.25 start frame delimiters, if the subframe payload can accommodate 2 synchronization words, the 2 synchronization words are mapped into the subframe payload of the single Wi-Fi subframe.

7. The method according to claim 6, characterized in that The source bit sequence also includes a LoRa payload, and the step of mapping the protocol data unit to the source bit sequence in the transmission resource unit also includes: If the subframe header is mapped to a LoRa payload, a mode symbol is marked at the position of the LoRa payload; If there is a LoRa payload with the same symbol as the pattern symbol in the LoRa payload, the pattern symbol is marked before the LoRa payload.

8. A cross-technology data transmission system from Wi-Fi to LoRa, comprising a processor and a memory, characterized in that: The memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory. When the computer instructions are executed by the processor, the system implements the steps of the method as described in any one of claims 1 to 7.

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