Ultra-wideband wireless communication method and device based on orthogonal bandwidth synthesis

Abstract

The invention discloses an ultra-wideband wireless communication method and device based on orthogonal bandwidth synthesis. In the ultra-wideband signal receiving method of one embodiment, an ultra-wideband signal is generated by synthesizing a baseband signal and a spread spectrum reference signal through orthogonal spread spectrum and orthogonal up-conversion, and the receiving method comprises the following steps: receiving the ultra-wideband signal through an antenna, inputting the ultra-wideband signal into a matching network to screen a frequency band, amplifying the frequency band, and transmitting the amplified ultra-wideband signal to the antenna; performing first-stage self-mixing through a first-stage envelope detector to obtain a reverse spread spectrum signal; the anti-spread spectrum signal is subjected to band-pass filtering and amplification and then enters a second-stage envelope detector to be subjected to second-stage self-mixing, so that the anti-spread spectrum signal subjected to band-pass filtering is moved to a base band; and the signal moved to the baseband is subjected to low-pass filtering to filter noise and interference signals, and finally, a digital signal corresponding to the baseband signal is obtained through a comparator. According to the invention, the system complexity and power consumption of the receiver can be greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication system design and digital and analog integrated circuit design, and relates to system engineering, communication engineering, integrated circuit design, etc., and specifically relates to a low-rate, ultra-low power consumption, ultra-wideband wireless communication method and device based on orthogonal bandwidth synthesis. Background Art

[0002] Ultra-wideband (UWB) technology has been widely used in radar systems since the last century, especially in the military field. Since radar resolution is directly related to bandwidth, UWB is often used in high-resolution applications, and such systems are called UWB radar or pulse radar. In recent years, thanks to the broadband characteristics of UWB, it has also attracted widespread attention in the field of communications. According to Shannon's formula, broadband means that larger amounts of data can be transmitted, so it has the potential for application in data-intensive scenarios. At present, UWB has achieved a number of research and commercial applications in the field of the Internet of Things (IoT), and has shown broad application prospects in biomedical engineering. For application scenarios with high data transmission requirements such as brain-computer interfaces, UWB technology can provide efficient wireless data links and is a very promising solution.

[0003] Existing technologies have increased data rates to the Gigabit per second (Gbps) level and achieved energy efficiency performance of less than 10pJ / b. However, in order to achieve such high performance, complex modulation schemes are often used, resulting in reduced receiver sensitivity and significantly increasing the complexity of the receiver design. In addition, this high data rate mode will significantly increase the power consumption of the transmitter and receiver, bringing challenges to the power consumption management of the device. In order to be able to add more digital bit modulation in each pulse cycle, the transmitter often requires a very accurate clock signal, and the use of phase-locked loops (PLLs) or injection locking to generate high-performance clock signals usually requires high power consumption. On the receiving end, in order to improve sensitivity to demodulate high-speed RF signals, the noise of the receiver needs to be kept at a low level, which greatly increases the power consumption of the low-noise amplifier (LNA), and the signal using pulse position modulation also requires a high-power precision time-to-digital converter (TDC) for demodulation, which increases the power consumption of the implanted transceiver to a level that is harmful to the human body.

[0004] However, in the field of biomedicine, especially in implantable devices, although the current ultra-wideband transmission equipment has reached the Gbps level, the system is complex, the power consumption is high, the reception and demodulation are difficult, and it is difficult to use it as a low-power implantable device. There is still no good solution to these problems. In practical applications, the high-speed mode only needs to be enabled in a small number of work tasks, and the device needs to work in low-power, low-speed mode most of the time. Therefore, a low-speed, ultra-low-power ultra-wideband wireless communication solution suitable for brain-computer interfaces is needed. Summary of the invention

[0005] The purpose of the present invention is to address the problems pointed out in the background technology and to propose a low-rate, ultra-low power consumption, ultra-wideband wireless communication method and device based on orthogonal bandwidth synthesis (Quadrature Bandwidth Synthesizing), which is particularly suitable for brain-computer interface application scenarios.

[0006] According to a first aspect of the present invention, there is provided a method for receiving an ultra-wideband signal, wherein the ultra-wideband signal is generated by synthesizing a baseband signal and a spread spectrum reference signal through orthogonal spread spectrum and orthogonal up-conversion, and the receiving method comprises:

[0007] The ultra-wideband signal is received via an antenna, input into a matching network to filter the frequency band and amplify it, and then passes through a first-stage envelope detector for first-stage self-mixing to obtain an inverse spread spectrum signal;

[0008] The despread spectrum signal is band-pass filtered and amplified before entering the second-stage envelope detector for second-stage self-mixing to move the despread spectrum signal after band-pass filtering to the baseband;

[0009] The signal moved to the baseband is low-pass filtered to filter out noise and interference signals, and finally a digital signal corresponding to the baseband signal is obtained through an analog-to-digital converter or a comparator.

[0010] According to a second aspect of the present invention, there is provided an ultra-wideband signal receiver for implementing the above-mentioned receiving method, comprising:

[0011] A signal preprocessing unit, used for filtering the frequency band of an ultra-wideband signal received via an antenna and amplifying the ultra-wideband signal, wherein the ultra-wideband signal is generated by synthesizing a baseband signal and a spread spectrum reference signal through orthogonal spread spectrum and orthogonal up-conversion;

[0012] A first-stage envelope detector is used to perform a first-stage self-mixing on the signal output by the signal preprocessing unit to obtain an inverse spread spectrum signal;

[0013] A first filtering unit, configured to perform bandpass filtering and amplify the despread spectrum signal;

[0014] A second-stage envelope detector, used for performing a second-stage self-mixing on the signal output by the first filtering unit, so as to move the despread spectrum signal after bandpass filtering to the baseband;

[0015] A second filtering unit, configured to perform low-pass filtering on the signal moved to the baseband to filter out noise and interference signals; and

[0016] The analog-to-digital converter or comparator outputs a digital signal corresponding to the baseband signal based on the low-pass filtered signal.

[0017] According to a third aspect of the present invention, there is provided an ultra-wideband signal transmission method, comprising:

[0018] generating a pseudo-random binary sequence as a reference signal;

[0019] Multiplying the baseband signal by the reference signal to obtain spread spectrum data;

[0020] Up-converting the reference signal to an intermediate frequency bandwidth to generate an intermediate frequency signal, wherein the intermediate frequency bandwidth is consistent with the bandwidth of the reference signal;

[0021] Adding the spread spectrum data to the intermediate frequency signal to form a pseudo ultra-wideband baseband signal; and

[0022] The pseudo ultra-wideband baseband signal is up-converted to a radio frequency band and sent through a power amplifier and an antenna.

[0023] According to a fourth aspect of the present invention, there is provided an ultra-wideband signal transmitter for implementing the transmission method as described above, comprising:

[0024] A bandwidth extension unit, configured to multiply a baseband signal by a reference signal to obtain bandwidth-extended spread spectrum data, wherein the reference signal is a pseudo-random binary sequence;

[0025] A first up-conversion unit, configured to receive the reference signal and up-convert the reference signal to an intermediate frequency bandwidth to generate an intermediate frequency signal, wherein the intermediate frequency bandwidth is consistent with the bandwidth of the reference signal;

[0026] an orthogonal bandwidth synthesis unit, configured to add the spread spectrum data and the intermediate frequency signal to form a pseudo ultra-wideband baseband signal; and

[0027] The second up-conversion unit is used to up-convert the pseudo ultra-wideband baseband signal to a radio frequency band to form a transmission signal for the power amplifier and the antenna to send out.

[0028] The wireless communication method and device proposed in the present invention synthesizes the low-speed baseband signal and the spread spectrum reference signal into an ultra-wideband signal through orthogonal spread spectrum and orthogonal up-conversion, reuses the frequency band of ultra-wideband technology and RF modules such as antennas and matching networks, and greatly reduces the system complexity and power consumption of the receiver. And because the synthesized signal carries the spread spectrum reference signal, the receiver does not need any prior knowledge, and only needs to perform second-order self-mixing on the signal to obtain the baseband signal, and has extremely strong narrowband anti-interference capabilities in the band, adjacent band and far band, and also has strong anti-interference capabilities for the ultra-wideband signal of normal up-conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The transmitter architecture based on orthogonal bandwidth synthesis of the present invention is shown.

[0030] Figure 2 Shows the Figure 1 Schematic diagram of the receiver architecture and signal flow calculation corresponding to the transmitter architecture.

[0031] Figure 3 A schematic diagram of a receiver architecture and a signal spectrum based on orthogonal bandwidth synthesis of the present invention. DETAILED DESCRIPTION

[0032] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0033] As described in the background technology, in the field of biomedicine, especially in the application of implantable devices such as brain-computer interface, the existing ultra-wideband transmitting equipment has problems such as complex system, high power consumption, and difficulty in receiving and demodulating. However, in practical applications, the high-speed mode only needs to be enabled in a small number of work tasks, and the device needs to work in low-power, low-speed mode most of the time. Therefore, based on the above requirements, the present invention designs a low-speed, ultra-low-power ultra-wideband wireless communication solution based on orthogonal bandwidth synthesis suitable for brain-computer interface, as well as the corresponding transmitter system design and receiver system design.

[0034] Figure 1 The architecture of the transmitter (Tx) of the low-rate ultra-low-power ultra-wideband wireless communication system based on orthogonal bandwidth synthesis of the present invention is shown, including a bandwidth extension unit 1, a first up-conversion unit 2, an orthogonal bandwidth synthesis unit 3 and a second up-conversion unit 4. The transmitter realizes the generation of UWB signals with low data rates through bandwidth extension and orthogonal bandwidth synthesis technology. In addition, orthogonal bandwidth synthesis eliminates the need for IQ up-conversion, thereby further reducing the power consumption of the transmitter. According to the IEEE protocol, the bandwidth of the UWB signal is 499.2 MHz (about 500 MHz), so a 125 MHz orthogonal bandwidth signal is used here for bandwidth extension.

[0035] like Figure 1As shown, first, a random pseudo-random binary sequence (PRBS) signal with a bandwidth of 125MHz is generated as a reference signal. The low data rate baseband (BB) signal carrying the information to be sent is multiplied with the PRBS reference signal at the bandwidth extension unit 1 to achieve bandwidth extension to 125MHz and generate spread spectrum data. Next, the PRBS reference signal is up-converted to an intermediate frequency (IF) bandwidth of 125MHz at the first up-conversion unit 2, and the IF signal is added to the spread spectrum data output by the bandwidth extension unit 1 at the orthogonal bandwidth synthesis unit 3 to form a pseudo-UWB baseband signal (because the combined signal contains 3 125MHz bandwidth signals, the total bandwidth reaches 250MHz). Finally, the pseudo-UWB baseband signal is up-converted to the radio frequency (RF) band at the second up-conversion unit 4 and sent out through the power amplifier (PA) and the antenna.

[0036] Compared with the traditional high-speed coherent transmitter structure, the transmitter of the present invention has the following advantages. First, the transmitted signal contains baseband data and reference signals, which means that the receiving end can demodulate the data only through the received signal without knowing the reference signal in advance. In addition, the baseband data adopts low-speed on-off keying (OOK) modulation, which greatly reduces power consumption compared with other high-speed complex modulation methods. At the same time, the intermediate frequency bandwidth is consistent with the reference signal bandwidth, so there is no need for IQ up-conversion, which further reduces power consumption.

[0037] Figure 2 and Figure 3 The invention shows the architecture of the receiving end (Rx) of the low-rate ultra-low-power ultra-wideband wireless communication system based on orthogonal bandwidth synthesis and its signal flow calculation and signal spectrum. Figure 1 As a non-coherent transceiver structure, since the synthesized ultra-wideband signal contains the spread-spectrum baseband data and the reference signal, the receiver can directly obtain the baseband data through two-stage self-mixing without obtaining prior knowledge in advance.

[0038] like Figure 2 and Figure 3 As shown, the antenna receives Figure 1 The UWB signal sent by the transmitter is shown in Figure 1. ant Indicates the amplitude of the signal received by the antenna, and then executes the processing flow from S1 to S6. First, in S1, the signal V antThe input matching network filters the frequency band and amplifies it. Since the UWB signal sent by the transmitter is in the RF band, the filtering frequency band of S1 is RF, which can be implemented by using RF bandpass filter RF_BPF. Then, the signal processed by S1 enters S2 for the first-stage RF envelope detector (RF Envelope Detector, RFED) self-mixing. This first-stage self-mixing can obtain the signal after the spread spectrum data is multiplied by the reference signal in the IF band, that is, the inverse spread spectrum signal. At the same time, the narrowband interference signal will also be "smoothed out" due to self-mixing, such as Figure 3 As shown in the spectrum diagram, it becomes broadband noise. Subsequently, after passing through the baseband bandpass filter (BB_BPF) at S3, most of the interference and noise can be filtered out. After that, self-mixing (BBED) is performed again at S4 to move the filtered despread spectrum signal obtained from S3 back to the baseband from the IF band. The signal processed by S4 is filtered out of noise and interference signals again through a low-pass filter (LPF) at S5, and finally a digital signal corresponding to the baseband signal at the transmitting end can be obtained through an ADC or a comparator, directly realizing on-chip digital output. Alternatively, according to test needs, the unconverted analog signal obtained after the LPF of S5 in this design can be strengthened through the baseband buffer (BBBUF) of S6 and then directly transmitted to the signal V BBBUF Externally connected to buffers and test instruments outside the chip. Figure 3 As shown, the above two solutions depend on the application scenario and can be selected by you.

[0039] like Figure 2 As shown, each level of processing in S1 to S5 is represented by a gain coefficient and the calculation formula of the entire data stream is given. The self-mixing elements in S2 and S4 are similar to the role of squarers in mathematical expressions, so Figure 2 In the data flow calculation formula shown in the figure, the signal undergoes a square operation each time it passes through a self-mixer, so the final output result of the baseband buffer is V BBBUF The gain of each level of components is nonlinear:

[0040]

[0041] Among them, V ant Indicates the amplitude of the signal received by the antenna, A IM represents the passive gain of the input matching network, K RF Represents the RF self-mixer gain proportionality coefficient, A BPF represents the bandpass filter (BPF) gain, K BB A represents the baseband self-mixer gain proportionality coefficient, LPF Represents the low-pass filter (LPF) gain.

[0042] It is worth noting that the present invention is different from the conventional receiver design. When the transmitter adopts up-conversion, a corresponding down-conversion unit is set in the conventional receiver, but the present invention uses self-mixing instead. In addition, the use of PRBS signal as a reference signal and the use of a comparator to replace the ADC in the conventional receiver are also features of the present invention.

[0043] The design of the present invention can significantly reduce the complexity of the system: the transmitter does not need high-power modules such as PLL and DTC, the maximum bandwidth synthesis rate is 125MHz, which can be achieved in the digital domain; the receiving end does not need to be synchronized with the transmitter, and there is no need to know the spread spectrum reference signal in advance. The self-mixing structure does not need a local oscillation signal (LO) for down-conversion, and on-off keying modulation (OOK) does not require the use of an analog-to-digital converter (ADC), and the comparator can obtain a digital signal.

[0044] The design of the present invention can also significantly reduce system power consumption: the power consumption of the receiver integrated circuit chip designed by the present invention is only 482.61 microwatts, while the power consumption of the existing high-speed ultra-wideband receiver is close to 8 milliwatts, and the power consumption of the receiver of the present invention is only one sixteenth of that. Those skilled in the art can understand that due to the lower system complexity and asynchronous architecture of the transmitter, the power consumption of the transmitter should also be significantly lower than that of the existing high-speed ultra-wideband transmitter.

Claims

1. A method for receiving an ultra-wideband signal, wherein the ultra-wideband signal is generated by synthesizing a baseband signal and a spread spectrum reference signal through orthogonal spread spectrum and orthogonal up-conversion, characterized in that: The receiving method comprises: The ultra-wideband signal is received via an antenna, input into a matching network to filter the frequency band and amplify it, and then passes through a first-stage envelope detector for first-stage self-mixing to obtain an inverse spread spectrum signal; The despread spectrum signal is band-pass filtered and amplified before entering the second-stage envelope detector for second-stage self-mixing to move the despread spectrum signal after band-pass filtering to the baseband; The signal moved to the baseband is low-pass filtered to filter out noise and interference signals, and finally a digital signal corresponding to the baseband signal is obtained through an analog-to-digital converter or a comparator.

2. The receiving method according to claim 1, characterized in that The baseband signal is a low-speed baseband signal with a data rate of 100 kbps to 1 Mbps after being modulated by low-speed on-off keying.

3. The receiving method according to claim 2, characterized in that: The spread spectrum reference signal is obtained by up-converting the reference signal to an intermediate frequency bandwidth, and the reference signal is a pseudo-random binary sequence; the inverse spread spectrum signal obtained by the first stage self-mixing corresponds to the result of multiplying the spread spectrum data by the reference signal, wherein the spread spectrum data is obtained by multiplying the baseband signal by the reference signal.

4. The receiving method according to claim 3, characterized in that: The intermediate frequency bandwidth is consistent with the bandwidth of the reference signal.

5. The receiving method according to claim 1, characterized in that: The ultra-wideband signal received via the antenna is in the radio frequency band, and the matching network is used to filter the radio frequency band.

6. The receiving method according to claim 1, characterized in that: Also includes: According to the test requirements, the signal after low-pass filtering is strengthened through the baseband buffer and then connected to the buffer outside the chip and the test instrument.

7. An ultra-wideband signal receiver implementing the receiving method according to any one of claims 1 to 6, characterized in that: include: A signal preprocessing unit, used for filtering the frequency band of an ultra-wideband signal received via an antenna and amplifying the ultra-wideband signal, wherein the ultra-wideband signal is generated by synthesizing a baseband signal and a spread spectrum reference signal through orthogonal spread spectrum and orthogonal up-conversion; A first-stage envelope detector is used to perform a first-stage self-mixing on the signal output by the signal preprocessing unit to obtain an inverse spread spectrum signal; A first filtering unit, configured to perform bandpass filtering and amplify the despread spectrum signal; A second-stage envelope detector, used for performing a second-stage self-mixing on the signal output by the first filtering unit, so as to move the despread spectrum signal after bandpass filtering to the baseband; A second filtering unit, configured to perform low-pass filtering on the signal moved to the baseband to filter out noise and interference signals; and The analog-to-digital converter or comparator outputs a digital signal corresponding to the baseband signal based on the low-pass filtered signal.

8. A method for transmitting an ultra-wideband signal, characterized in that: include: generating a pseudo-random binary sequence as a reference signal; Multiplying the baseband signal by the reference signal to obtain spread spectrum data; Up-converting the reference signal to an intermediate frequency bandwidth to generate an intermediate frequency signal, wherein the intermediate frequency bandwidth is consistent with the bandwidth of the reference signal; Adding the spread spectrum data to the intermediate frequency signal to form a pseudo ultra-wideband baseband signal; and The pseudo ultra-wideband baseband signal is up-converted to a radio frequency band and sent through a power amplifier and an antenna.

9. The transmitting method according to claim 8, characterized in that: Before multiplying the baseband signal with the reference signal, the method further includes performing low-speed on-off keying modulation on the baseband signal so that the data rate of the baseband signal is between 100 kbps and 1 Mbps.

10. An ultra-wideband signal transmitter implementing the transmission method according to claim 8 or 9, characterized in that: include: A bandwidth extension unit, configured to multiply a baseband signal by a reference signal to obtain bandwidth-extended spread spectrum data, wherein the reference signal is a pseudo-random binary sequence; A first up-conversion unit, configured to receive the reference signal and up-convert the reference signal to an intermediate frequency bandwidth to generate an intermediate frequency signal, wherein the intermediate frequency bandwidth is consistent with the bandwidth of the reference signal; an orthogonal bandwidth synthesis unit, configured to perform signal addition on the spread spectrum data and the intermediate frequency signal to form a pseudo ultra-wideband baseband signal; and The second up-conversion unit is used to up-convert the pseudo ultra-wideband baseband signal to a radio frequency band to form a transmission signal for the power amplifier and the antenna to send out.

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