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

Abstract

The present invention discloses an ultra-wideband wireless communication method and device based on orthogonal bandwidth synthesis. In an ultra-wideband signal receiving method of one embodiment, 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. The receiving method includes: receiving the ultra-wideband signal via an antenna, inputting a matching network to filter the frequency band and amplifying it, and then passing through a first-stage envelope detector to perform a first-stage self-mixing to obtain an inverse spread spectrum signal; the inverse spread spectrum signal is band-pass filtered and amplified, and then enters a second-stage envelope detector to perform a second-stage self-mixing to move the band-pass filtered inverse spread spectrum signal 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 a comparator. The present invention can greatly reduce the system complexity and power consumption of the receiver.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication system design and digital and analog integrated circuit design, and involves 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. Such systems are called UWB radars or pulse radars. 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 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 highly promising solution.

[0003] Existing technologies have increased data rates to gigabits per second (Gbps) and achieved energy efficiency of less than 10 pJ / b. However, to achieve such high performance, complex modulation schemes are often employed, resulting in reduced receiver sensitivity and significantly increasing the complexity of receiver design. Furthermore, this high data rate significantly increases power consumption at both the transmitter and receiver, posing challenges for device power management. To accommodate more digital bits per pulse cycle, transmitters often require highly accurate clock signals. Generating high-performance clock signals using methods such as phase-locked loops (PLLs) or injection locking typically consumes significant power. On the receiver side, to improve sensitivity and demodulate high-speed RF signals, receiver noise must be kept low, significantly increasing the power consumption of the low-noise amplifier (LNA). Signals using pulse position modulation also require a high-power, precise time-to-digital converter (TDC) for demodulation, increasing the power consumption of implantable transceivers to levels that could be hazardous to the human body.

[0004] However, in the biomedical field, especially in implantable devices, although current ultra-wideband transmitters have achieved Gbps speeds, they still face complex systems, high power consumption, and difficulty in receiving and demodulating, making them difficult to use as low-power implantable devices. In practical applications, high-speed mode is only required for a small number of tasks, while the device must operate 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 propose a low-rate, ultra-low power consumption, ultra-wideband wireless communication method and device based on quadrature bandwidth synthesis, which is particularly suitable for brain-computer interface application scenarios.

[0006] According to a first aspect of the present invention, a method for receiving an ultra-wideband signal is provided, 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, the receiving method comprising:

[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 to perform 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 baseband;

[0009] The signal moved to the baseband is low-pass filtered to remove 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, configured to filter a frequency band of an ultra-wideband signal received via an antenna and amplify 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 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, configured to perform 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 a baseband;

[0015] A second filtering unit is configured to perform low-pass filtering on the signal moved to the baseband to remove 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 a method for transmitting an ultra-wideband signal, comprising:

[0018] Generate 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 transmitted 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 the 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 this invention combine a low-speed baseband signal with a spread-spectrum reference signal into an ultra-wideband signal through orthogonal spread spectrum and orthogonal up-conversion. This reuses the frequency bands of ultra-wideband technology, as well as RF modules such as antennas and matching networks, significantly reducing the receiver's system complexity and power consumption. Furthermore, because the synthesized signal includes the spread-spectrum reference signal, the receiver requires no prior knowledge and only needs to perform second-order self-mixing on the signal to obtain the baseband signal. The device also exhibits strong anti-interference capabilities against narrowband interference within the band, adjacent band, and far-band, as well as against normally up-converted ultra-wideband signals. 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 Schematic diagram of the receiver architecture and 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 interfaces, existing ultra-wideband transmitting devices have problems such as complex systems, high power consumption, and difficulty in receiving and demodulating. However, in actual applications, the high-speed mode only needs to be enabled in a small number of work tasks, and the device needs to be kept in low-power, low-speed mode for 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 interfaces, as well as the corresponding transmitter system design and receiver system design.

[0034] Figure 1 The present invention shows the architecture of the transmitter (Tx) of a low-rate, ultra-low-power, ultra-wideband wireless communication system based on orthogonal bandwidth synthesis, 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 generates low-data-rate UWB signals 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 (approximately 500 MHz), so a 125 MHz orthogonal bandwidth signal is used here for bandwidth extension.

[0035] like Figure 1As shown, a random 125MHz bandwidth pseudo-random binary sequence (PRBS) signal is first generated as a reference signal. A low-data-rate baseband (BB) signal carrying the information to be transmitted is multiplied by the PRBS reference signal at the bandwidth extension unit 1 to achieve bandwidth expansion to 125MHz and generate spread spectrum data. Next, the PRBS reference signal is up-converted to a 125MHz intermediate frequency (IF) bandwidth at the first up-conversion unit 2. The IF signal and the spread spectrum data output by the bandwidth extension unit 1 are added at the orthogonal bandwidth synthesis unit 3 to form a pseudo-UWB baseband signal (because the combined signal contains three 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 transmitted through the power amplifier (PA) and antenna.

[0036] Compared to traditional high-speed coherent transmitter architectures, the transmitter of this invention offers the following advantages. First, the transmitted signal contains both baseband data and a reference signal, meaning the receiver can demodulate the data using only the received signal, without requiring prior knowledge of the reference signal. Furthermore, the baseband data utilizes low-speed on-off keying (OOK) modulation, significantly reducing power consumption compared to other high-speed, complex modulation schemes. Furthermore, the intermediate frequency bandwidth matches the reference signal bandwidth, eliminating the need for IQ upconversion and further reducing power consumption.

[0037] Figure 2 and Figure 3 The present 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.

[0038] like Figure 2 and Figure 3 As shown, the antenna receives Figure 1 The UWB signal sent by the transmitter is V ant Indicates the amplitude of the signal received by the antenna, and then the processing flow from S1 to S6 is executed. 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 achieved by using RF bandpass filtering RF_BPF. Then, the signal processed by S1 enters S2 and undergoes self-mixing in the first-stage RF envelope detector (RF Envelope Detector, RFED). 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 again filtered out of noise and interference signals through a low-pass filter (LPF) at S5, and finally a digital signal corresponding to the baseband signal at the transmitter can be obtained through an ADC or 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 needs of the application scenario and can be selected by you.

[0039] like Figure 2 As shown, each stage 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, 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 proportional coefficient, A BPF represents the bandpass filter (BPF) gain, K BB A represents the baseband self-mixer gain proportional coefficient, LPF Indicates the low-pass filter (LPF) gain.

[0042] It is worth noting that the present invention differs from conventional receiver designs. While conventional receivers typically incorporate a downconversion unit when the transmitter employs upconversion, the present invention employs self-mixing as a replacement. Furthermore, the present invention employs a PRBS signal as a reference signal and a comparator in place of the ADC in conventional receivers.

[0043] The design of the present invention can significantly reduce system complexity: the transmitter does not require high-power modules such as PLL and DTC, and the maximum bandwidth synthesis rate is 125MHz, which can be implemented 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 require a local oscillator signal (LO) for down-conversion, and on-off keying modulation (OOK) does not require an analog-to-digital converter (ADC), and a comparator can obtain a digital signal.

[0044] The design of this invention also significantly reduces system power consumption: the receiver integrated circuit chip designed in this invention consumes only 482.61 microwatts. Existing high-speed ultra-wideband receivers consume approximately 8 milliwatts, while the power consumption of this invention's receiver is only one-sixteenth of that. Those skilled in the art will appreciate that, thanks to the transmitter's reduced system complexity and asynchronous architecture, the power consumption of the transmitter should also be significantly lower than that of existing high-speed ultra-wideband transmitters.

Claims

1. A method for receiving an ultra-wideband signal, wherein the ultra-wideband signal is generated by: Generate a pseudo-random binary sequence as a reference signal; multiplying the baseband signal by the reference signal to obtain spread spectrum data; The reference signal is up-converted 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; 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 to perform 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 baseband; The signal moved to the baseband is low-pass filtered to remove 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, wherein 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, wherein: The inverse spread spectrum signal obtained by the first stage self-mixing corresponds to a result of multiplying 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, wherein: The intermediate frequency bandwidth is consistent with the bandwidth of the reference signal.

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

6. The receiving method according to claim 1, wherein: Also includes: According to the test requirements, the low-pass filtered signal is amplified 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, configured to filter a frequency band of an ultra-wideband signal received via an antenna and amplify 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 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, configured to perform 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 a baseband; A second filtering unit is configured to perform low-pass filtering on the signal moved to the baseband to remove 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: Generate 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 transmitted through a power amplifier and an antenna.

9. The transmitting method according to claim 8, wherein: 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 add 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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