A radio frequency circuit and electronic device based on optical fiber

Abstract

The present application provides an optical fiber-based radio frequency circuit and electronic device, wherein the optical fiber-based radio frequency circuit includes a baseband signal processing system, an analog optical fiber system, a terminal radio frequency front-end system and an antenna connected in sequence; the baseband signal processing system sets a first analog bus interface based on the MIPI RFFE protocol; the terminal radio frequency front-end system sets a second analog bus interface based on the MIPI RFFE protocol, so that the antenna transmits and receives the information data through a wireless radio frequency signal; the first end of the analog optical fiber system is connected to the first analog bus interface, and the second end of the analog optical fiber system is connected to the second analog bus interface, which is used to establish an optical signal transceiver channel, so as to convert the analog signal into an optical signal for transceiver transmission based on wavelength division multiplexing. The present application uses radio frequency optical fiber technology to achieve the remoteness of the radio frequency interface under low loss, ensure the transmission power requirement of the antenna system, and improve the transmission efficiency of the communication system.

Description

Technical Field

[0001] The present application relates to the technical field of Internet of Things, and in particular to a radio frequency circuit and electronic device based on optical fiber. Background Art

[0002] In the RF terminals of the Internet of Things and the Internet of Vehicles currently used in mobile wireless communications, based on the appropriate processing of the information to be sent, the antenna system is connected to the RF cable and sent to the RF space; or the RF signal sent by the base station is received by the antenna system and transmitted to the signal processing system through the RF cable. In the communication system where the antenna system and the signal processing system are connected by the RF cable, it is required that the RF cable should not cause too much loss to the RF signal.

[0003] In the process of conceiving and implementing this application, the inventors found that there are at least the following problems: With the development of the RF needs of the Internet of Things, higher frequency segments and more RF scenarios are used. For example, in the 5G and 6G era, due to the increase in bandwidth, the frequency of the carrier has been increased to 3.5GHz / 4.9GHz / 5.8GHz / 6.2GHz or even the high-frequency segment of the millimeter wave. For example, for the Internet of Vehicles or indoor Internet of Things applications, the antenna system and the terminal module are often far apart. In RF scenarios with higher frequency segments and larger spacing distances, the loss caused by the RF cable will increase sharply, causing a sharp drop in the transmission power of the antenna port, which not only wastes energy but also greatly affects the communication efficiency of the communication module. Summary of the invention

[0004] In order to alleviate the above problems, the present application provides an optical fiber-based radio frequency circuit, including a baseband signal processing system, an analog optical fiber system, a terminal radio frequency front-end system and an antenna connected in sequence:

[0005] The baseband signal processing system sets a first analog bus interface based on the MIPI RFFE protocol, and is used to perform frequency conversion filtering processing of analog signals on the terminal radio frequency signal according to the information data received and sent;

[0006] The terminal radio frequency front-end system sets a second analog bus interface based on the MIPI RFFE protocol, and amplifies and adjusts the analog signal according to the working parameters of the antenna, so that the antenna sends and receives the information data through a wireless radio frequency signal;

[0007] The first end of the analog optical fiber system is connected to the first analog bus interface, and the second end of the analog optical fiber system is connected to the second analog bus interface, which is used to establish an optical signal transceiver channel to convert the analog signal into an optical signal for transceiver transmission based on wavelength division multiplexing.

[0008] Optionally, the analog optical fiber system uses wavelength division multiplexing to perform transmission and reception, including:

[0009] A first frequency band is used to transmit a radio frequency transmission or a radio frequency reception signal, and the first frequency band selection interval is between 450 MHz and 6500 MHz.

[0010] Optionally, the analog optical fiber system uses wavelength division multiplexing to perform transmission and reception, including:

[0011] The SCLK modulated signal of the MIPI RFFE protocol is transmitted using the second frequency band, and the second frequency band selection interval is between 312 MHz and 368 MHz.

[0012] Optionally, the analog optical fiber system uses wavelength division multiplexing to perform transmission and reception, including:

[0013] The SDATA modulated signal of the MIPI RFFE protocol is transmitted using a third frequency band, and the third frequency band selection interval is between 372 MHz and 428 MHz.

[0014] Optionally, a protection bandwidth of at least 4 MHz is reserved between the second frequency band and the third frequency band.

[0015] Optionally, the MIPI RFFE protocol signal is modulated using BPSK or OOK modulation technology.

[0016] Optionally, the radio frequency circuit further includes a terminal baseband system, which is connected to the baseband signal processing system and is used to perform analog-to-digital conversion on the information data.

[0017] Optionally, the simulated optical fiber system includes a first radio frequency optical fiber unit, a second radio frequency optical fiber unit and a simulated optical fiber, and the first radio frequency optical fiber unit and the second radio frequency optical fiber unit are connected via the simulated optical fiber.

[0018] Optionally, the first radio frequency optical fiber unit includes a first wavelength division multiplexer, a first radio frequency combiner, a first radio frequency splitter and a first transceiver switch;

[0019] The optical fiber end of the first wavelength division multiplexer is connected to the first end of the simulated optical fiber, the output end of the first radio frequency combiner is connected to the input end of the first wavelength division multiplexer, the first input end of the first radio frequency combiner is connected to the first radio frequency input signal of the first end of the simulated optical fiber system, and the second input end of the first radio frequency combiner is connected to the first SCLK modulation signal of the first end of the simulated optical fiber system;

[0020] The input end of the first RF splitter is connected to the output end of the first wavelength division multiplexer, the first output end of the first RF splitter outputs the first RF output signal of the first end of the analog optical fiber system, and the second output end of the first RF splitter is connected to the first active end of the first transceiver switch;

[0021] The fixed end of the first transceiver switching switch serves as the first SDATA modulation signal port of the first end of the analog optical fiber system, the clock end of the first transceiver switching switch is connected to the first SCLK modulation signal of the first end of the analog optical fiber system, and the second active end of the first transceiver switching switch is connected to the third input end of the first RF combiner.

[0022] Optionally, the first radio frequency optical fiber unit further includes:

[0023] A first modulation filter, wherein the second input end of the first radio frequency combiner constructs a first SCLK modulation signal port of the first end of the analog optical fiber system through the first modulation filter.

[0024] Optionally, the first radio frequency optical fiber unit further includes:

[0025] A second modulation filter, wherein the second active end of the first transceiver switch is connected to the third input end of the first RF combiner through the second modulation filter.

[0026] Optionally, the first radio frequency optical fiber unit further includes:

[0027] A third modulation filter, wherein the second output end of the first RF splitter is connected to the input end of the first transceiver switch through the third modulation filter.

[0028] Optionally, the first radio frequency optical fiber unit further includes:

[0029] The first optical power detector detects the radio frequency signal level at the output end of the first wavelength division multiplexer to adjust the optical power of the simulated optical fiber according to a first preset strategy.

[0030] Optionally, the second radio frequency optical fiber unit includes a second wavelength division multiplexer, a second radio frequency combiner, a second radio frequency splitter and a second transceiver switch;

[0031] The output end of the second RF combiner is connected to the input end of the second wavelength division multiplexer, the first input end of the second RF combiner is connected to the second RF input signal of the second end of the analog optical fiber system, and the second input end of the second RF combiner is connected to the first active end of the second transceiver switch;

[0032] The output end of the second wavelength division multiplexer is connected to the input end of the second radio frequency splitter, and the optical fiber end of the second wavelength division multiplexer is connected to the second end of the analog optical fiber;

[0033] The first output end of the second RF splitter outputs the second RF output signal of the second end of the simulated optical fiber system, the second output end of the second RF splitter is connected to the second active end of the second transceiver switch, and the third output end of the second RF splitter is connected to the clock end of the second transceiver switch and serves as the second SCLK modulation signal port of the second end of the simulated optical fiber system;

[0034] The fixed end of the second transceiver switch serves as the second SDATA modulation signal port of the second end of the analog optical fiber system.

[0035] Optionally, the second radio frequency optical fiber unit further includes:

[0036] The fourth modulation filter is connected between the third output terminal of the second RF splitter and the clock terminal of the second transceiver switch.

[0037] Optionally, the second radio frequency optical fiber unit further includes:

[0038] a fifth modulation filter connected between the second output terminal of the second RF splitter and the second active terminal of the second transceiver switch;

[0039] Optionally, the second radio frequency optical fiber unit further includes:

[0040] The sixth modulation filter is connected to the second input end of the second RF combiner and the first active end of the second transceiver switch.

[0041] Optionally, the second radio frequency optical fiber unit further includes:

[0042] The second optical power detector detects the radio frequency signal level at the output end of the second wavelength division multiplexer to adjust the optical power of the simulated optical fiber according to a second preset strategy.

[0043] Optionally, the second radio frequency optical fiber unit further includes:

[0044] A power amplifier, wherein the first output end of the second radio frequency splitter outputs a second radio frequency output signal of the second end of the analog optical fiber system through the power amplifier.

[0045] Optionally, the second radio frequency optical fiber unit further includes:

[0046] A low noise amplifier, wherein the first input end of the second radio frequency combiner is connected to the second radio frequency input signal of the second end of the analog optical fiber system through the low noise amplifier.

[0047] Optionally, the analog optical fiber system includes a plurality of optical power distribution combiners, and the radio frequency circuit includes a plurality of terminal radio frequency front-end systems;

[0048] The multiple optical power distribution combiners are connected in series to the first end of the analog optical fiber system, and each optical power distribution combiner is connected to a terminal RF front-end system; the baseband signal processing system is the master device of the MIPI RFFE protocol bus, and the multiple terminal RF front-end systems are the slave devices of the MIPI RFFE protocol bus.

[0049] The present application also provides an electronic device, including the optical fiber-based RF circuit as described above, the electronic device including a first circuit board and a second circuit board, the baseband signal processing system is arranged on the first circuit board, and the terminal RF front-end system is arranged on the second circuit board.

[0050] The optical fiber-based RF circuit and electronic device provided in the present application use a baseband signal processing system to set a first analog bus interface based on the MIPI RFFE protocol, which is used to perform frequency conversion and filtering processing on the terminal RF signal according to the information data received and sent; the terminal RF front-end system sets a second analog bus interface based on the MIPI RFFE protocol, and amplifies and adjusts the analog signal according to the working parameters of the antenna, so that the antenna can receive and send the information data through a wireless RF signal; the first end of the analog optical fiber system is connected to the first analog bus interface, and the second end of the analog optical fiber system is connected to the second analog bus interface, which is used to establish an optical signal receiving and sending channel, so as to convert the analog signal into an optical signal for receiving and sending based on wavelength division multiplexing; the RF optical fiber technology is used to achieve the remoteness of the RF interface under low loss, ensure the transmission power requirement of the antenna system, and improve the transmission efficiency of the communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application. In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0052] Figure 1 This is a block diagram of a radio frequency circuit of the present application.

[0053] Figure 2 This is a schematic diagram of a radio frequency terminal system based on simulated optical fiber according to an embodiment of the present application.

[0054] Figure 3 A schematic diagram of a simulated optical fiber system according to an embodiment of the present application.

[0055] The realization of the purpose, functional features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. The above-mentioned drawings have shown clear embodiments of this application, which will be described in more detail later. These drawings and textual descriptions are not intended to limit the scope of the concept of this application in any way, but to illustrate the concept of this application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0056] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0057] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0058] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0059] First embodiment

[0060] The present application provides a radio frequency circuit based on optical fiber. Figure 1 This is a block diagram of a radio frequency circuit of the present application.

[0061] like Figure 1 As shown, the optical fiber-based radio frequency circuit includes a baseband signal processing system 1, an analog optical fiber system 2, a terminal radio frequency front-end system 3 and an antenna 4 which are connected in sequence.

[0062] The baseband signal processing system 1 sets a first analog bus interface based on the MIPI RFFE protocol. The baseband signal processing system 1 can perform frequency conversion filtering processing of analog signals on the terminal radio frequency signal according to the information data received and sent.

[0063] The terminal RF front-end system 3 sets a second analog bus interface based on the MIPI RFFE protocol. The terminal RF front-end system 3 can amplify and adjust the analog signal according to the working parameters of the antenna, so that the antenna 4 can send and receive the information data through a wireless RF signal.

[0064] The first end of the analog optical fiber system 2 is connected to the first analog bus interface, and the second end of the analog optical fiber system 2 is connected to the second analog bus interface. The analog optical fiber system 2 is used to establish an optical signal transceiver channel to convert the analog signal into an optical signal for transceiver transmission based on wavelength division multiplexing.

[0065] Figure 2 This is a schematic diagram of a radio frequency terminal system based on simulated optical fiber according to an embodiment of the present application.

[0066] Exemplarily, an Internet of Things and Internet of Vehicles terminal applied to mobile communications 4G / 5G / 6G / NTN (Non-Terrestrial Networks, satellite mobile Internet) may include two parts: a terminal module and an antenna subsystem.

[0067] In the communication components of the terminal module, units such as the terminal baseband subsystem (SoC, System-On-Chip), the terminal RF front-end subsystem (FEM / PA, Front End Module, Power Amplifier), and the terminal RF small signal subsystem (RFIC, Radio Frequency Integrated Circuit) can be set.

[0068] Exemplarily, the terminal RF small signal subsystem can be used as a baseband signal processing system, mainly performing signal processing at the small signal level, such as the signal strength range of (-120dBm to -10dBm), processing baseband signal to RF up and down conversion, signal amplification, signal filtering, etc.

[0069] Exemplarily, the terminal RF front-end subsystem can be used as a terminal RF front-end system, mainly including a front-end frequency switching switch (Switch), a filter (Filter), a receiving low noise amplifier (LNA, Low Noise Amplifier), and a power amplifier (PA, Power Amplifier). The power amplifier amplifies the transmit signal to a maximum of 23dBm to 26dBm and sends it to the antenna.

[0070] Please continue to refer to Figure 2 Optionally, the radio frequency circuit also includes a terminal baseband system 5, which is connected to the baseband signal processing system 1 and is used to perform analog-to-digital conversion on the information data.

[0071] Exemplarily, the terminal baseband subsystem can serve as a terminal baseband system, which can process the 4G / 5G physical layer (PHY, Physical), media access layer (MAC, Media Access Control), radio resource control layer (RRC, Radio Resource Control), non-access layer protocol family (NAS, Non-Access Stratum), and high-level application processing (AP, Application Process) software.

[0072] Exemplarily, the antenna of the antenna subsystem can radiate the signal amplified by the power amplifier in the FEM into the wireless space, and receive the signal sent by the base station at the receiving end, and connect to the FEM through the signal transmission channel.

[0073] For example, MIPI RFFE (Radio Frequency Front-End) is an interface standard defined by the MIPI Alliance specifically for RF front-end devices, and is mainly used for the interconnection of RF transceiver circuits in mobile devices and IoT devices.

[0074] The MIPI RFFE bus is a two-wire bus that can be used to program control registers inside RFFE devices. The MIPI serial data interface consists of SCLK and SDATA. SCLK is a gated clock that can reach 26MHz and 52MHz in RFFE devices. SDATA is a bidirectional pin that enables the interface to read and write slave registers.

[0075] Please continue to refer to Figure 2 In this application, the interface between RFIC and FEM / PA is set as two analog optical fiber interfaces between two circuit boards, and they are connected to each other through analog optical fiber. This interface mainly includes the RF transmit / receive interface (RFTX / RX) and the MIPI RFFE interface for RFIC to control FEM / PA. The MIPI RFFE interface mainly transmits various digital control instructions based on the RFFE specification.

[0076] Exemplarily, the present application uses analog optical fiber ROF (Radio-Over-Fiber) technology to convert RF TX / RX and MIPIRFFE interface to one optical fiber for transmission. ROF technology is a transmission technology that loads radio frequency (RF) signal or intermediate frequency (IF) signal onto an optical carrier, uses optical fiber as a transmission medium, and then reaches the receiving end. As a branch technology of microwave photonic technology, ROF technology has the advantages of both wireless communication and optical fiber communication. ROF technology combines the characteristics of optical fiber communication and wireless communication, and has huge advantages in large-capacity, high-frequency band wireless access networks. ROF technology can overcome the "electronic bottleneck" problem, is easy to maintain, and has low cost. ROF technology can realize the processing of large-bandwidth, high-frequency band signals in the optical domain, and has the advantages of large bandwidth and low loss.

[0077] Optionally, the analog optical fiber system uses wavelength division multiplexing to perform transmission and reception, including:

[0078] A first frequency band is used to transmit a radio frequency transmission or a radio frequency reception signal, and the first frequency band selection interval is between 450 MHz and 6500 MHz.

[0079] For example, analog optical fiber can use multi-carrier technology to modulate RF TX / RX, MIPI RFFE SCLK and MIPI RFFE SDATA onto different carriers for frequency division multiplexing for transmission. For example, the F0 frequency band (450MHz to 6500MHz) can be used to transmit RF TX / RX signals of 4G / 5G / 6G / NTN.

[0080] Optionally, the analog optical fiber system uses wavelength division multiplexing to perform transmission and reception, including:

[0081] The SCLK modulated signal of the MIPI RFFE protocol is transmitted using the second frequency band, and the second frequency band selection interval is between 312 MHz and 368 MHz.

[0082] Exemplarily, in the setting of the F1 frequency band, 56 MHz (312-368 MHz) of the 340 MHz center frequency can be used to transmit the digital modulation signal of the SCLK of the MIPI RFFE.

[0083] Optionally, the analog optical fiber system uses wavelength division multiplexing to perform transmission and reception, including:

[0084] The SDATA modulated signal of the MIPI RFFE protocol is transmitted using a third frequency band, and the third frequency band selection interval is between 372 MHz and 428 MHz.

[0085] Exemplarily, in the setting of the F2 frequency band, 56 MHz (372-428 MHz) of the 400 MHz center frequency can be used to transmit the digital modulated signal of SDATA of MIPI RFFE.

[0086] It should be noted that the above frequencies are not fixed. What is given here is a frequency reuse allocation strategy, which can be ultimately allocated according to the actual usage of the wireless network, as long as frequency division multiplexing is met and there is enough bandwidth to transmit the digital signal modulation signals of MIPI RFFE's SCLK and SDATA.

[0087] Optionally, a protection bandwidth of at least 4 MHz is reserved between the second frequency band and the third frequency band.

[0088] Exemplarily, F1 (SCLK of MIPI RFFE) and F2 (SDATA of MIPI RFFE) reserve a 4 MHz protection bandwidth (368-372 MHz).

[0089] Optionally, the MIPI RFFE protocol signal is modulated using BPSK or OOK modulation technology.

[0090] The digital modulation technology of MIPI RFFE's SCLK and MIPI RFFE's SDATA can use BPSK (Binary Phase Shift Keying) or OOK (On-Off Keying) to reduce link delay. At the same time, a filter is placed after digital modulation to ensure that there is no adjacent channel interference between the three carrier signals of frequency division multiplexing.

[0091] Please refer to Figure 2 , Optionally, the analog optical fiber system includes a plurality of optical power distribution combiners 23, and the radio frequency circuit includes a plurality of terminal radio frequency front-end systems 3;

[0092] The multiple optical power distribution combiners 23 are connected in series to the first end of the analog optical fiber system 2, and each optical power distribution combiner 23 is connected to a terminal RF front-end system 3; the baseband signal processing system 1 is the master device of the MIPI RFFE protocol bus, and the multiple terminal RF front-end systems 3 are the slave devices of the MIPI RFFE protocol bus.

[0093] Please continue to refer to Figure 2 For example, the present application uses an optical power distribution combiner to implement the MIPI RFFE bus, ensuring that an RFFE master device (RFFE Master) of an RFIC can mount multiple RFFE slave devices (RFFE Slave).

[0094] Second embodiment

[0095] Please continue to refer to Figure 2 On the basis of the above-mentioned embodiment, optionally, the simulated optical fiber system 2 includes a first RF optical fiber unit 21, a second RF optical fiber unit 22 and a simulated optical fiber, and the first RF optical fiber unit 21 and the second RF optical fiber unit 22 are connected via the simulated optical fiber.

[0096] Exemplarily, the present application sets the interface between RFIC and FEM / PA as two simulated optical fiber interfaces between two circuit boards, namely, a first radio frequency optical fiber unit and a second radio frequency optical fiber unit. The first radio frequency optical fiber unit serves as the first end of the simulated optical fiber system, and the second radio frequency optical fiber unit serves as the second end of the simulated optical fiber system. The present application uses simulated optical fiber ROF (Radio-Over-Fiber) technology to convert the RF TX / RX and MIPI RFFE interfaces to one optical fiber for transmission.

[0097] Figure 3 A schematic diagram of a simulated optical fiber system according to an embodiment of the present application.

[0098] like Figure 3 As shown, optionally, the first radio frequency optical fiber unit 21 includes a first wavelength division multiplexer 211 , a first radio frequency combiner 212 , a first radio frequency splitter 213 and a first transceiver switch 214 .

[0099] The optical fiber end of the first wavelength division multiplexer 211 is connected to the first end of the analog optical fiber, the output end of the first RF combiner 212 is connected to the input end of the first wavelength division multiplexer 211, the first input end of the first RF combiner 212 is connected to the first RF input signal of the first end of the analog optical fiber system, and the second input end of the first RF combiner 212 is connected to the first SCLK modulation signal of the first end of the analog optical fiber system.

[0100] The input end of the first RF splitter 213 is connected to the output end of the first wavelength division multiplexer 211, the first output end of the first RF splitter 213 outputs the first RF output signal of the first end of the analog optical fiber system, and the second output end of the first RF splitter 213 is connected to the first active end of the first transceiver switching switch 214.

[0101] The fixed end of the first transceiver switching switch 214 serves as the first SDATA modulation signal port of the first end of the analog optical fiber system, the clock end of the first transceiver switching switch 214 is connected to the first SCLK modulation signal of the first end of the analog optical fiber system, and the second active end of the first transceiver switching switch 214 is connected to the third input end of the first RF combiner 212.

[0102] For example, wavelength division multiplexing technology is a communication technology that combines a series of optical signals carrying information but with different wavelengths into one beam and transmits it along a single optical fiber; at the receiving end, a certain method is used to separate the optical signals of different wavelengths. This technology can transmit multiple signals on a single optical fiber at the same time, and each signal is transmitted by a certain wavelength of light, which is a wavelength channel. In the same optical fiber, allowing two or more optical wavelength signals to transmit information through different optical channels at the same time is called optical wavelength division multiplexing technology, referred to as WDM. Optical wavelength division multiplexing can also be called frequency division multiplexing. There is no obvious difference between optical frequency division multiplexing (FDM) technology and optical wavelength division multiplexing (WDM) technology, because light waves are part of electromagnetic waves, and the frequency and wavelength of light have a single corresponding relationship. It can also be generally understood that optical frequency division multiplexing refers to the subdivision of optical frequencies, and optical channels are very dense. Optical wavelength division multiplexing refers to the coarse division of optical frequencies, and optical channels are far apart, even in different windows of optical fibers. Optical wavelength division multiplexing generally uses wavelength division multiplexers and demultiplexers (also called combiners / combiners / demultiplexers / splitters) placed at both ends of the optical fiber to achieve the coupling and separation of different light waves. The principles of these two devices are the same.

[0103] For example, since the SDATA of MIPI RFFE is bidirectional, a transceiver switch is designed to control the switching between the transmission mode and the reception mode.

[0104] If it is initially in the sending mode, the tail of the frame sent by the RFFE with several frame structures is detected, and when it is determined that the sending frame has been completed, it switches to the receiving mode.

[0105] If in the receiving mode, the transmission frame tails of several frame structures received by RFFE are detected, and when it is determined that the reception frame has been completed, it switches to the transmitting mode.

[0106] For example, please refer to Table 1, which lists the lengths of SDATA frames in different frame formats. The switch identifies the end of the frame through the lengths of different types of frames.

[0107] Table 1: Lengths of five MIPI RFFE command frames

[0108]

[0109] In this embodiment, since there is no need to parse the content of the MIPI RFFE protocol and only the length of the frame needs to be parsed, it can be implemented using simple digital logic.

[0110] Please continue to refer to Figure 3 Optionally, the first radio frequency optical fiber unit 21 further includes:

[0111] The first modulation filter 215 , the second input end of the first RF combiner 212 constructs the first SCLK modulation signal port of the first end of the analog optical fiber system through the first modulation filter 215 .

[0112] A filter can be a filter circuit composed of capacitors, inductors and resistors. The filter can effectively filter out a specific frequency point in the power line or frequencies other than the frequency point to obtain a power signal of a specific frequency, or eliminate a power signal after a specific frequency. A filter is a frequency selection device that allows specific frequency components in a signal to pass through while greatly attenuating other frequency components. The frequency selection function of the filter can be used to filter out interference noise or perform spectrum analysis.

[0113] Optionally, the first radio frequency optical fiber unit 21 further includes:

[0114] A second modulation filter 216 , wherein the second active end of the first transceiver switch 214 is connected to the third input end of the first RF combiner 212 through the second modulation filter 216 .

[0115] Optionally, the first radio frequency optical fiber unit 21 further includes:

[0116] A third modulation filter 217 , wherein the second output end of the first RF splitter 213 is connected to the input end of the first transceiver switch 214 through the third modulation filter 217 .

[0117] Optionally, the first radio frequency optical fiber unit 21 further includes:

[0118] The first optical power detector 218 detects the radio frequency signal level at the output end of the first wavelength division multiplexer 211 to adjust the optical power of the simulated optical fiber according to a first preset strategy.

[0119] An optical power detector is an instrument used to measure the size of optical power. It can be used for direct measurement of optical power and relative measurement of optical attenuation. For example, through the optical power detection technology, the optical power received in the receiving direction of the radio frequency circuit is identified by the first optical power detector and compared with the first optical power threshold. According to the comparison result, the signal quality of the optical fiber output can be automatically adjusted to compensate for the power loss caused by the excessive length of the optical fiber and the optical splitter.

[0120] Optionally, the second radio frequency optical fiber unit 22 includes a second wavelength division multiplexer 221 , a second radio frequency combiner 222 , a second radio frequency splitter 223 and a second transceiver switch 224 .

[0121] The output end of the second RF combiner 222 is connected to the input end of the second wavelength division multiplexer 221, the first input end of the second RF combiner 222 is connected to the second RF input signal of the second end of the analog optical fiber system, and the second input end of the second RF combiner 222 is connected to the first active end of the second transceiver switching switch 224.

[0122] The output end of the second wavelength division multiplexer 221 is connected to the input end of the second radio frequency splitter 223 , and the optical fiber end of the second wavelength division multiplexer 221 is connected to the second end of the analog optical fiber.

[0123] The first output end of the second RF splitter 223 outputs the second RF output signal of the second end of the analog optical fiber system, the second output end of the second RF splitter 223 is connected to the second active end of the second transceiver switching switch 224, and the third output end of the second RF splitter is connected to the clock end of the second transceiver switching switch 224 and serves as the second SCLK modulation signal port of the second end of the analog optical fiber system.

[0124] The fixed end of the second transceiver switch 224 serves as the second SDATA modulation signal port of the second end of the analog optical fiber system.

[0125] Optionally, the second radio frequency optical fiber unit 22 further includes:

[0126] The fourth modulation filter 225 is connected between the third output terminal of the second RF splitter 223 and the clock terminal of the second transceiver switch 224 .

[0127] Optionally, the second radio frequency optical fiber unit 22 further includes:

[0128] The fifth modulation filter 226 is connected between the second output terminal of the second RF splitter 223 and the second active terminal of the second transceiver switch 224 .

[0129] Optionally, the second radio frequency optical fiber unit 22 further includes:

[0130] The sixth modulation filter 227 is connected to the second input terminal of the second RF combiner 222 and the first active terminal of the second transceiver switch 224 .

[0131] Optionally, the second radio frequency optical fiber unit 22 further includes:

[0132] The second optical power detector 228 detects the radio frequency signal level at the output end of the second wavelength division multiplexer 221 to adjust the optical power of the simulated optical fiber according to a second preset strategy.

[0133] Exemplarily, through optical power detection technology, a second optical power detector identifies the optical power received by the RF circuit in the external transmission direction and compares it with a second optical power threshold. Based on the comparison result, the signal quality of the optical fiber output can be automatically adjusted to compensate for the power loss caused by the excessive length of the optical fiber and the optical splitter.

[0134] Optionally, the second radio frequency optical fiber unit 22 further includes:

[0135] A low noise amplifier 220 , wherein the first input end of the second RF combiner 222 is connected to the second RF input signal of the second end of the analog optical fiber system through the low noise amplifier 220 .

[0136] A low noise amplifier is an amplifier with a very low noise coefficient. It can be used in high-frequency or medium-frequency preamplifiers, as well as amplifier circuits of highly sensitive electronic detection equipment, to reduce noise and improve the output signal-to-noise ratio.

[0137] Optionally, the second radio frequency optical fiber unit 22 further includes:

[0138] The power amplifier 229 is used for outputting the second RF output signal of the second end of the analog optical fiber system through the first output end of the second RF splitter 223 .

[0139] A power amplifier (PA) is a type of amplifier that is mainly used for power amplification output. The purpose of using a power amplifier is not only to focus on gain, but also to squeeze out as much RF signal as possible from the signal.

[0140] The fiber-based RF circuit provided in this embodiment increases the distance between the ROF and MIPI RFFE interfaces based on analog optical fiber, which can effectively alleviate the problem of transmission power loss in high-frequency and vehicle networking and satellite communication scenarios, greatly improve the transmission power of the terminal, and improve the communication rate of the entire RF terminal.

[0141] Third embodiment

[0142] The present application also provides an electronic device, including the optical fiber-based RF circuit as described above, the electronic device including a first circuit board and a second circuit board, the baseband signal processing system is arranged on the first circuit board, and the terminal RF front-end system is arranged on the second circuit board.

[0143] In this embodiment, a new architecture of the radio frequency circuit of the electronic device is constructed based on the wavelength division multiplexing technology of analog optical fiber, and the interface between the RFIC and FEM / PA in a circuit board is changed from a general intra-board interface to an inter-board interface, thereby increasing the distance between the ROF and MIPI RFFE interfaces based on the wavelength division multiplexing technology of analog optical fiber.

[0144] The optical fiber-based RF circuit and electronic device provided in the present application use a baseband signal processing system to set a first analog bus interface based on the MIPI RFFE protocol, which is used to perform frequency conversion and filtering processing on the terminal RF signal according to the information data received and sent; the terminal RF front-end system sets a second analog bus interface based on the MIPI RFFE protocol, and amplifies and adjusts the analog signal according to the working parameters of the antenna, so that the antenna can receive and send the information data through a wireless RF signal; the first end of the analog optical fiber system is connected to the first analog bus interface, and the second end of the analog optical fiber system is connected to the second analog bus interface, which is used to establish an optical signal receiving and sending channel, so as to convert the analog signal into an optical signal for receiving and sending based on wavelength division multiplexing; the RF optical fiber technology is used to achieve the remoteness of the RF interface under low loss, ensure the transmission power requirement of the antenna system, and improve the transmission efficiency of the communication system.

[0145] It is understood that the above scenarios are only examples and do not constitute a limitation on the application scenarios of the technical solutions provided in the embodiments of the present application. The technical solutions of the present application can also be applied to other scenarios. For example, it is known to those skilled in the art that with the evolution of the system architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0146] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0147] The steps in the method of the embodiment of the present application can be adjusted in order, combined and deleted according to actual needs.

[0148] The units in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0149] In the present application, the same or similar terminology concepts, technical solutions and / or application scenario descriptions are generally described in detail only the first time they appear. When they appear again later, they are generally not repeated for the sake of brevity. When understanding the technical solutions and other contents of the present application, for the same or similar terminology concepts, technical solutions and / or application scenario descriptions that are not described in detail later, reference can be made to the previous related detailed descriptions.

[0150] In the present application, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0151] The various technical features of the technical solution of the present application can be arbitrarily combined. In order to make the description concise, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present application.

[0152] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A radio frequency circuit based on optical fiber, characterized in that: An Internet of Things terminal applied to mobile communications, the Internet of Things terminal includes a terminal module and an antenna subsystem, the terminal module is provided with a terminal RF small signal subsystem and a terminal RF front-end subsystem; the antenna of the antenna subsystem radiates the signal in the terminal RF front-end subsystem into the wireless space, and receives the signal sent by the base station at the receiving end, and is connected to the terminal RF front-end subsystem through a signal transmission channel; the RF circuit includes a baseband signal processing system, an analog optical fiber system, a terminal RF front-end system and an antenna connected in sequence: The baseband signal processing system sets a first analog bus interface based on the MIPI RFFE protocol, and is used to perform frequency conversion filtering processing of analog signals on the terminal radio frequency signal according to the information data received and sent; The terminal radio frequency small signal subsystem serves as the baseband signal processing system; The terminal RF front-end system sets a second analog bus interface based on the MIPI RFFE protocol, and amplifies and adjusts the analog signal according to the working parameters of the antenna, so that the antenna sends and receives the information data through a wireless RF signal; the terminal RF front-end subsystem serves as the terminal RF front-end system; The first end of the analog optical fiber system is connected to the first analog bus interface, and the second end of the analog optical fiber system is connected to the second analog bus interface, which is used to establish an optical signal transceiver channel to convert the analog signal into an optical signal for transceiver transmission based on wavelength division multiplexing.

2. The optical fiber-based radio frequency circuit according to claim 1, characterized in that: The process of the analog optical fiber system using wavelength division multiplexing to perform transmission and reception includes at least one of the following: A first frequency band is used to transmit a radio frequency transmission or a radio frequency reception signal, wherein the first frequency band is selected between 450 MHz and 6500 MHz; The SCLK modulation signal of the MIPI RFFE protocol is transmitted using a second frequency band, wherein the second frequency band selection interval is between 312 MHz and 368 MHz; The SDATA modulated signal of the MIPI RFFE protocol is transmitted using a third frequency band, and the third frequency band selection interval is between 372 MHz and 428 MHz.

3. The optical fiber-based radio frequency circuit according to claim 2, characterized in that: A protection bandwidth of at least 4 MHz is reserved between the second frequency band and the third frequency band; And / or, the MIPI RFFE protocol signal is modulated using BPSK or OOK modulation technology; And / or, the radio frequency circuit also includes a terminal baseband system, which is connected to the baseband signal processing system and is used to perform analog-to-digital conversion on the information data.

4. The optical fiber-based radio frequency circuit according to claim 1, characterized in that: The simulated optical fiber system includes a first radio frequency optical fiber unit, a second radio frequency optical fiber unit and a simulated optical fiber, and the first radio frequency optical fiber unit and the second radio frequency optical fiber unit are connected via the simulated optical fiber.

5. The optical fiber-based radio frequency circuit according to claim 4, characterized in that: The first radio frequency optical fiber unit includes a first wavelength division multiplexer, a first radio frequency combiner, a first radio frequency splitter and a first transceiver switch; The optical fiber end of the first wavelength division multiplexer is connected to the first end of the simulated optical fiber, the output end of the first radio frequency combiner is connected to the input end of the first wavelength division multiplexer, the first input end of the first radio frequency combiner is connected to the first radio frequency input signal of the first end of the simulated optical fiber system, and the second input end of the first radio frequency combiner is connected to the first SCLK modulation signal of the first end of the simulated optical fiber system; The input end of the first RF splitter is connected to the output end of the first wavelength division multiplexer, the first output end of the first RF splitter outputs the first RF output signal of the first end of the analog optical fiber system, and the second output end of the first RF splitter is connected to the first active end of the first transceiver switch; The fixed end of the first transceiver switching switch serves as the first SDATA modulation signal port of the first end of the analog optical fiber system, the clock end of the first transceiver switching switch is connected to the first SCLK modulation signal of the first end of the analog optical fiber system, and the second active end of the first transceiver switching switch is connected to the third input end of the first RF combiner.

6. The optical fiber-based radio frequency circuit according to claim 5, characterized in that: The first radio frequency optical fiber unit further includes at least one of the following: a first modulation filter, wherein the second input end of the first RF combiner constructs a first SCLK modulation signal port of the first end of the analog optical fiber system through the first modulation filter; a second modulation filter, wherein the second active end of the first transceiver switch is connected to the third input end of the first RF combiner through the second modulation filter; a third modulation filter, wherein the second output end of the first RF splitter is connected to the input end of the first transceiver switch through the third modulation filter; The first optical power detector detects the radio frequency signal level at the output end of the first wavelength division multiplexer to adjust the optical power of the simulated optical fiber according to a first preset strategy.

7. The optical fiber-based radio frequency circuit according to claim 4, characterized in that: The second radio frequency optical fiber unit includes a second wavelength division multiplexer, a second radio frequency combiner, a second radio frequency splitter and a second transceiver switch; The output end of the second RF combiner is connected to the input end of the second wavelength division multiplexer, the first input end of the second RF combiner is connected to the second RF input signal of the second end of the analog optical fiber system, and the second input end of the second RF combiner is connected to the first active end of the second transceiver switch; The output end of the second wavelength division multiplexer is connected to the input end of the second radio frequency splitter, and the optical fiber end of the second wavelength division multiplexer is connected to the second end of the analog optical fiber; The first output end of the second RF splitter outputs the second RF output signal of the second end of the simulated optical fiber system, the second output end of the second RF splitter is connected to the second active end of the second transceiver switch, and the third output end of the second RF splitter is connected to the clock end of the second transceiver switch and serves as the second SCLK modulation signal port of the second end of the simulated optical fiber system; The fixed end of the second transceiver switch serves as the second SDATA modulation signal port of the second end of the analog optical fiber system.

8. The optical fiber-based radio frequency circuit according to claim 7, characterized in that: The second radio frequency optical fiber unit further includes at least one of the following: a fourth modulation filter connected between the third output terminal of the second RF splitter and the clock terminal of the second transceiver switch; a fifth modulation filter connected between the second output terminal of the second RF splitter and the second active terminal of the second transceiver switch; a sixth modulation filter connected to the second input end of the second RF combiner and the first active end of the second transceiver switch; a second optical power detector for detecting a radio frequency signal level at an output end of the second wavelength division multiplexer to adjust the optical power of the simulated optical fiber by a second preset strategy; a power amplifier, wherein the first output end of the second radio frequency splitter outputs a second radio frequency output signal of the second end of the analog optical fiber system through the power amplifier; A low noise amplifier, wherein the first input end of the second radio frequency combiner is connected to the second radio frequency input signal of the second end of the analog optical fiber system through the low noise amplifier.

9. The optical fiber-based radio frequency circuit according to any one of claims 1 to 8, characterized in that: The analog optical fiber system includes a plurality of optical power distribution combiners, and the radio frequency circuit includes a plurality of terminal radio frequency front-end systems; The multiple optical power distribution combiners are connected in series to the first end of the analog optical fiber system, and each optical power distribution combiner is connected to a terminal RF front-end system; the baseband signal processing system is the master device of the MIPI RFFE protocol bus, and the multiple terminal RF front-end systems are the slave devices of the MIPI RFFE protocol bus.

10. An electronic device, characterized in that: Comprising the optical fiber-based radio frequency circuit as described in any one of claims 1-9, the electronic device comprises a first circuit board and a second circuit board, the baseband signal processing system is arranged on the first circuit board, and the terminal radio frequency front-end system is arranged on the second circuit board.

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