Patent Publication Number: US-2022231722-A1

Title: Communication circuit and communication device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a national stage filing under 35 U.S.C. § 371 of international application number PCT/CN2020/100988, filed Jul. 9, 2020, which claims priority to Chinese patent application No. 201910888490.6, filed Sep. 19, 2019. The contents of these applications are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of communication, for example, to a communication circuit and a communication device. 
     BACKGROUND 
     The  5 th generation mobile communication system new radio (5G NR) has two operation modes, one is stand-alone (SA) mode without 4G assistance, and the other is non-SA mode with 4G signaling assistance. No matter which mode is employed, 3G and 4G are standard configurations on mobile terminals. Therefore, 5G terminals are bound to coexist with 3G, 4G, and even 2G that has not been completely eliminated. According to a frequency band planning proposed by the  3 rd generation partnership project (3GPP), 5G includes sub 6G and millimeter wave spectrum resources, where sub 6G is distributed below 6GHz. For the sake of saving money and spectrum multiplexing, some operators intend to share spectrum resources between long term evolution (LTE) and 5G. For example, LTE band 41 and 5G N41 share the spectrum of 2496˜2690 MHz. However, the 5G modules introduced by chip solution manufacturers are relatively independent of 4G modules, so there is a need to add more circuits and antennas to support both 4G and 5G systems. 
     4G and 5G circuits are independent of each other, which will occupy more additional circuit area for a mobile terminal with a precious small size. Moreover, when 4G and 5G antennas support 4×4 multiple input multiple output (MIMO) respectively, there are a large number of antennas on a mobile phone. In related art, the number of antennas on the terminal is reduced by sharing some antennas, thereby simplifying the antenna layout and wiring on the terminal. However, antenna combining by filter alone has a great loss on the path. 
     SUMMARY 
     In order to at least solve the problems of complicated circuit layout and large number of antennas in the terminal device caused by the independence of 5G module and 4G module and more circuits and antennas to support both 4G and 5G systems, according to some embodiments of the present disclosure, a communication circuit and a communication device are provided. 
     According to some embodiments of the present disclosure, a communication circuit is provided, including a signal reception multiplexing circuit including a multiplexing antenna, a signal separation module connected to the multiplexing antenna, and a first signal demodulation module and a second signal demodulation module respectively connected to the signal separation module. 
     The multiplexing antenna is configured to receive a first signal and a second signal having the same frequency band and send the received signals to the signal separation module; and 
     The signal separation module is configured to separate the first signal and the second signal from the received signals, send the separated first signal to the first signal demodulation module for demodulation processing, and send the separated second signal to the second signal demodulation module for demodulation processing. 
     According to some embodiments of the present disclosure, a communication device is further provided, including the communication circuit described above. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram of a hardware structure diagram of a mobile terminal according to an embodiment of the present disclosure; 
         FIG. 2  is an architecture diagram of a communication network system according to an embodiment of the present disclosure; 
         FIG. 3  is a schematic diagram of a communication circuit according to embodiment I of the present disclosure; 
         FIG. 4  is a schematic diagram of a communication circuit according to embodiment II of the present disclosure; 
         FIG. 5  is a schematic diagram of a communication circuit according to embodiment III of the present disclosure; and 
         FIG. 6  is a structural diagram of a communication circuit according to embodiment IV of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure will be explained by the embodiments in conjunction with the drawings. The embodiments described herein are intended to explain and not to limit the present disclosure. 
     In the following description, suffixes such as “module”, “component” or “unit” used to represent elements are for facilitating the description of the present disclosure, and have no specific meaning. Therefore, “module”, “component” or “unit” can be mixed in used. 
     A terminal device can be implemented in various forms. For example, the terminal device described in the present disclosure may include a mobile terminal such as a mobile phone, a tablet, a laptop, a handheld computer, a personal digital assistant (PDA), a portable media player (PMP), a navigation device, a wearable device, a smart bracelet, a pedometer, and a fixed terminal such as a digital television (TV), a desktop computer. 
     In the following description, a mobile terminal will be taken as an example. Except for the elements specified for mobile purposes, the configuration of the mobile terminal according to the embodiments of the present disclosure can also be applied to a fixed type of terminal devices. 
       FIG. 1  is a schematic diagram of a hardware structure of a mobile terminal according to an embodiment of the present disclosure. As shown in  FIG. 1 , the mobile terminal  100  may include a radio frequency (RF) unit  101 , a Wi-Fi module  102 , an audio output unit  103 , an audio/video (A/V) input unit  104 , a sensor  105 , a display unit  106 , a user input unit  107 , an interface unit  108 , a memory  109 , a processor  110 , a power supply  111 , an antenna  112 , etc. The mobile terminal  100  shown in  FIG. 1  includes at least four groups of antennas  112 . Among the at least four groups of antennas  112 , antennas connected to a main transceiver channel of the mobile terminal  100  are main antennas, and antennas connected to an auxiliary receiver channel of the mobile terminal  100  are auxiliary antennas. The processor  110  is configured to control the connection and disconnection of each group of antennas with the main transceiver channel and the auxiliary receiver channel, respectively. When the processor  110  controls a group of antennas to connect to the main transceiver channel, the RF unit  101  can receive or transmit signals through the group of antennas. The at least four groups of antennas  112  can be flexibly arranged at any position of the mobile terminal  100 . For example, when the mobile terminal  100  includes four groups of antennas  112 , the four groups of antennas  112  can be respectively arranged at the upper, middle, lower left and lower right of the back of the mobile terminal  100 . The mobile terminal structure shown in  FIG. 1  does not constitute a limitation of the mobile terminal, and the mobile terminal may include more or less components than shown, or a combination of some components, or different component arrangements. 
     The components of the mobile terminal are described below with reference to  FIG. 1 . 
     The RF unit  101  can be configured to receive and transmit signals during transmitting and receiving information or calling. After downlink information from a base station is received, the processor  110  processes the downlink information. In addition, uplink data are sent to the base station. Generally, the RF unit  101  includes, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, and the like. In addition, the RF unit  101  are configured to communicate with a network and other devices through wireless communication as well. Any communication standards or protocols can be used for the above wireless communication, including but not limited to, global system of mobile communication (GSM), general packet radio service (GPRS), code division multiple access 2000 (CDMA2000), wideband code division multiple access (WCDMA), time division-synchronous code division multiple access (TD-SCDMA), frequency division duplexing-long term evolution, FDD-LTE) and time division duplexing-long term evolution (TDD-LTE), etc. 
     Wi-Fi is a short-distance wireless transmission technology. The mobile terminal can help users send and receive e-mails, browse web pages and access streaming media through the Wi-Fi module  102 , which provides users with wireless broadband Internet access. Although a Wi-Fi module  102  is shown in  FIG. 1 , the Wi-Fi module  102  does not belong to a necessary component of the mobile terminal, and can be omitted as required without altering the essence of the present disclosure. 
     The audio output unit  103  is configured to convert audio data received by the RF unit  101  or the Wi-Fi module  102  or stored in the memory  109  into audio signals and output them as sounds when the mobile terminal  100  is in a call signal reception mode, a talk mode, a recording mode, a voice recognition mode, a broadcast reception mode, etc. Furthermore, the audio output unit  103  is further configured to provide audio outputs related to specific functions performed by the mobile terminal  100  (for example, call signal reception sound, message reception sound, etc.). The audio output unit  103  may include a speaker, a buzzer, and the like. 
     The A/V input unit  104  is configured to receive audio or video signals. The A/V input unit  104  may include a graphics processing unit (GPU)  1041  and a microphone  1042 . The GPU  1041  processes image data of a static picture or video obtained by an image capture device (such as a camera) in a video capture mode or an image capture mode. The processed image frame may be displayed on the display unit  106 . The image frame processed by the GPU  1041  can be stored in the memory  109  (or other storage medium) or transmitted via the RF unit  101  or the Wi-Fi module  102 . The microphone  1042  is configured to receive sounds (audio data) via the microphone  1042  in an operation mode such as a telephone talk mode, a recording mode, a voice recognition mode, and the like, and can process such sounds into audio data. The processed audio (voice) data can be converted into a format output that can be transmitted to the mobile communication base station via the RF unit  101  in the telephone talk mode. The microphone  1042  can implement various types of noise elimination (or suppression) algorithms to eliminate (or suppress) noise or interference generated during receiving and transmitting of audio signals. 
     The mobile terminal  100  further includes at least one sensor  105 , such as a light sensor, a motion sensor and other sensors. The light sensor includes an ambient light sensor and a proximity sensor. The ambient light sensor is configured to adjust the brightness of a display panel  1061  according to the brightness of ambient light, and the proximity sensor is configured to turn off the display panel  1061  and/or backlight when the mobile terminal  100  is moved to ears. As a kind of motion sensor, the accelerometer sensor is configured to detect the acceleration in multiple directions (generally triaxial), and detect the magnitude and direction of gravity at rest. The accelerometer sensor is configured to identify the application of mobile phone attitude (such as horizontal and vertical screen switching, related games, magnetometer attitude calibration), vibration recognition related functions (such as pedometer, knocking), etc. Other sensors such as a fingerprint sensor, a pressure sensor, an iris sensor, a molecular sensor, a gyroscope, a barometer, a hygrometer, a thermometer, an infrared sensor, etc., which can also be configured in the mobile phone, will not be described in detail here. 
     The display unit  106  is configured to display information input by a user or information provided to the user. The display unit  106  may include a display panel  1061 , which may be configured in the form of a liquid crystal display (LCD), an organic light emitting diode (OLED), etc. 
     The user input unit  107  can be configured to receive input digital or character information and generate key signal input related to user settings and function control of the mobile terminal. The user input unit  107  may include a touch panel  1071  and other input devices  1072 . The touch panel  1071 , also known as a touch screen, is configured to collect the user&#39;s touch operations on or near the touch panel  1071  (such as the user&#39;s operations on or near the touch panel  1071  with a finger, a stylus or any other suitable objects or accessories), and drive the corresponding connecting means according to a preset program. The touch panel  1071  may include a touch detection means and a touch controller. The touch detection means is configured to detect the user&#39;s touch orientation, detect the signal brought by the touch operation, and transmit the signal to the touch controller. The touch controller receives touch information from the touch detection device, converts the touch information into contact coordinates, and sends the coordinates to the processor  110 . Further, the touch controller is configured to receive and execute commands sent by the processor  110 . In addition, the touch panel  1071  may be implemented as resistive, capacitive, infrared and surface acoustic wave touch panels, etc. In addition to the touch panel  1071 , the user input unit  107  may also include other input devices  1072 . Other input devices  1072  may include, but are not limited to, one or more of physical keyboard, function key (such as volume control key, switch key, etc.), trackball, mouse, joystick, etc., which are not limited here. 
     The touch panel  1071  is arranged to cover the display panel  1061 . When a touch operation on or near the touch panel  1071  is detected, the touch operation is transmitted to the processor  110  to determine the type of touch event, and then the processor  110  provides corresponding visual output on the display panel  1061  according to the type of touch event. Although in  FIG. 1 , the touch panel  1071  and the display panel  1061  realize the input and output functions of the mobile terminal as two independent components, in some embodiments, the touch panel  1071  and the display panel  1061  can be integrated to realize the input and output functions of the mobile terminal, which is not limited here. 
     The interface unit  108  is configured to serve as an interface through which at least one external device can be connected to the mobile terminal  100 . For example, the external device may include a wired or wireless headset port, an external power supply (or battery charger) port, a wired or wireless data port, a memory card port, a port configured to connect a device having an identification module, an audio input/output (I/O) port, a video I/O port, a headset port, and the like. The interface unit  108  can be configured to receive input (e.g., data information, power, etc.) from the external device and transmit the received input to one or more elements within the mobile terminal  100 , or can be configured to transmit data between the mobile terminal  100  and the external device. 
     The memory  109  can be configured to store software programs and various data. The memory  109  may mainly include a program storage area and a data storage area. The program storage area may be configured to store an operating system, an application program required by at least one function (such as a sound playing function, an image playback function), etc. The data storage area may be configured to store data (such as audio data, phone book, etc.) created according to the use of the mobile phone. In addition, the memory  109  may include high-speed random access memory, and may also include a nonvolatile memory, such as at least one magnetic disk memory device, a flash memory device, or other volatile solid-state memory devices. 
     The processor  110  is a control center of the mobile terminal, which connects multiple parts of the whole mobile terminal using various interfaces and lines, executes various functions of the mobile terminal and processes data by running or executing software programs and/or modules stored in the memory  109  and invoking data stored in the memory  109 , so as to carry out overall monitoring of the mobile terminal. The processor  110  may include one or more processing units. The processor  110  may integrate an application processor and a modem processor, where the application processor mainly processes the operating system, user interface and application programs, and the modem processor mainly processes wireless communication. It can be understood that the above modem processor may not be integrated into the processor  110 . 
     The mobile terminal  100  may further include a power supply  111  (such as a battery) for supplying power to a plurality of components. The power supply  111  may be logically connected to the processor  110  through a power management system, so that functions such as charge and discharge management and power consumption management can be realized through the power management system. 
     Although not shown in  FIG. 1 , the mobile terminal  100  may also include a Bluetooth module, etc., which will not be described in detail here. 
     In order to facilitate understanding of the embodiments of the present disclosure, the communication network system on which the mobile terminal of the present disclosure is based will be described below. 
       FIG. 2  is an architecture diagram of a communication network system according to an embodiment of the present disclosure. As shown in  FIG. 2 , the communication network system is a LTE system of the universal mobile communication technology, and the LTE system includes a user equipment (UE)  201 , an evolved universal mobile telecommunications system terrestrial radio access network (E-UTRAN)  202 , an evolved packet core (EPC)  203  and an internet protocol (IP) service of operators  204 , which are communicatively connected to each other in turn. 
     The UE  201  may be the above mobile terminal  100 , which is not described in detail here. 
     The E-UTRAN  202  includes an evolved NodeB (eNodeB)  2021  and other eNodeBs  2022 . The eNodeB  2021  can be connected to other eNodeBs  2022  through a backhaul (e.g., X2 interface). The eNodeB  2021  is connected to the EPC  203 , and can provide access from the UE  201  to the EPC  203 . 
     The EPC  203  may include a mobility management entity (MME)  2031 , a home subscriber server (HSS)  2032 , other MMES  2033 , a serving gate way (SGW)  2034 , a packet data network gate way (PGW)  2035  and a policy and charging rules function (PCRF)  2036 . The MME  2031  is a control node that processes signaling between the UE  201  and the EPC  203 , providing bearer and connection management. The HSS  2032  is configured to provide some registers such as home location registers (not shown) for describer management, and to store some subscriber specific information about service characteristics, data rate, etc. All subscriber data can be sent through the SGW  2034 . The PGW  2035  can provide IP address allocation and other functions of the UE  201 . The PCRF  2036  is a decision point for service data flow and IP Bearer resource policy and charging control policy, which selects and provides available policies and charging control decisions for a policy and charging execution function unit (not shown). 
     The IP service  204  may include internet, intranet, IP multimedia subsystem (IMS) or other IP services. 
     Although the LTE system is described above as an example, the present disclosure is not only applicable to LTE system, but also applicable to other wireless communication systems, such as GSM, CDMA2000, WCDMA, TD-SCDMA and future new network systems, etc., which is not limited here. 
     Based on the hardware structure of the mobile terminal and the communication network system described above, some embodiments of the present disclosure are illustrated. 
     Embodiment I 
     In order to at least partially solve the problems of complicated circuit layout and large number of antennas on the terminal caused by the independence of 5G module and 4G module and the need to add more circuits and antennas to support both 4G and 5G systems, according to some embodiments of the present disclosure, a communication circuit is provided. 
     For 5G millimeter wave frequency band, 5G RF circuit and antenna cannot be shared due to great difference between 5G operating frequency and 2G\3G\4G operating frequency, but for the sub 6G spectrum, a large part of 5G spectrum overlaps with 2G\3G\4G spectrum. In view of these possible frequency combinations, in order to solve the above technical problems, a communication circuit is provided, including a signal reception multiplexing circuit. The signal reception multiplexing circuit includes a multiplexing antenna, a signal separation module connected to the multiplexing antenna, and a first signal demodulation module and a second signal demodulation module respectively connected to the signal separation module. The multiplexing antenna is configured to receive a first signal and a second signal having the same frequency band and send the received signals to the signal separation module, and the signal separation module is configured to separate the first signal and the second signal from the received signals, send the separated first signal to the first signal demodulation module for demodulation processing, and send the separated second signal to the second signal demodulation module for demodulation processing. 
     In an embodiment of the present disclosure, the first signal is a 5G signal, and the second signal is at least one of 2G, 3G and 4G signals having the same frequency band as the first signal. The signal separation module includes a power divider, which performs signal separation processing for the received signals to separate the first signal and the second signal from the received signals, and then distributes the separated first signal and second signal to the corresponding first signal demodulation module and second signal demodulation module for signal demodulation processing. In an embodiment of the present disclosure, the signal separation module is not limited to the power divider, and may also be any signal separation device that can perform signal separation processing on the signals to separate the first signal and the second signal from the signals. An appropriate signal separation module can be selected as required. 
     The signal reception multiplexing circuit further includes a filter processing module arranged between the multiplexing antenna and the signal separation module, and the filter processing module is configured to filter the signals received by the multiplexing antenna and send the filtered signals to the signal separation module. 
     In an embodiment of the present disclosure, the filter processing module includes a band-pass filter which performs band-pass filtering for the first signal and the second signal having the same frequency band received by the multiplexing antenna to suppress out-of-band noise. In an embodiment of the present disclosure, the filter processing module includes, but is not limited to, the band-pass filter, and may also be any appropriate filter processing module that can perform band-pass filtering for the received first signal and second signal. An appropriate filter processing module can be selected as required. 
     The signal reception multiplexing circuit also includes a low noise processing module arranged between the filter processing module and the signal separation module, and the low noise processing module is configured to amplify weak signals after filtering by the filter processing module. 
     In an embodiment of the present disclosure, the low noise processing module includes a low noise amplifier arranged between the filter processing module and the signal separation module, and the low noise processing module is configured to pre-amplify the weak signals after the first signal and the second signal received by the multiplexing antenna are filtered by the filter processing module, and can reduce the deterioration degree of signal-to-noise ratio caused by a post-stage signal separation module, so as to provide an appropriate gain for a post-stage signal amplification processing. 
     The signal receiving multiplexing circuit also includes a first signal amplification processing module arranged between the signal separation module and the first signal demodulation module, and a second signal amplification processing module arranged between the signal separation module and the second signal demodulation module. 
     In an embodiment of the present disclosure, the first signal amplification processing module and the second signal amplification processing module include an adjustable gain low noise amplifier. Since the amplitudes of the received 4G and 5G signals are different, it may need to separately perform adjustable gain amplification, so that the first signal and the second signal respectively amplified by the adjustable gain amplifier can reach specific amplitudes. Then, the subsequent signal demodulation processing is performed. In an embodiment of the present disclosure, the signal processing module also includes a mixer, which performs a frequency conversion processing for the signals reaching the specific amplitude after processed by the adjustable gain amplifier, generates a baseband signal after the frequency conversion processing, and sends the baseband signal to a non-demodulation unit for demodulation processing. 
     In an embodiment of the present disclosure, the communication circuit may also include a transmission antenna and a signal transmission processing circuit connected to the transmission antenna. 
     The transmission antenna includes a first signal transmission antenna and a second signal transmission antenna, and the signal transmission processing circuit includes a first signal transmission processing circuit and a second signal transmission processing circuit. 
     In an embodiment of the present disclosure, at least one transmission antenna and a signal transmission processing circuit connected to the transmission antenna may be included. When the signal reception multiplexing circuit includes one transmission antenna, the signal transmission antenna may be the first signal transmission antenna or the second signal transmission antenna. 
     In an embodiment of the present disclosure, in the signal reception multiplexing circuit, a multiplexing antenna in at least one signal reception multiplexing circuit is also connected to a signal transmission processing circuit and a duplexer, where the signal transmission processing circuit is connected to the multiplexing antenna through the duplexer and the signal separation module is connected to the multiplexing antenna through the duplexer; and the multiplexing antenna is configured to receive and transmit the first signal or the second signal. 
     In an embodiment of the present disclosure, the duplexer filters the received signal and the transmitted signal of the multiplexing antenna, respectively, transmits the received signal of the multiplexing antenna to the signal separation module after filtering, and transmits the transmitted signal to the multiplexing antenna after filtering. 
     In an example of the embodiment of the present disclosure, the signal reception multiplexing circuit includes two signal reception multiplexing circuits, and multiplexing antennas in the two signal reception multiplexing circuits are also connected to signal transmission processing circuits and duplexers, where one signal transmission processing circuit is a first signal transmission processing circuit and the other signal transmission processing circuit is a second signal transmission processing circuit. 
     In this example, the multiplexing antennas in the two signal reception multiplexing circuits are also connected to signal transmission processing circuits and duplexers, where the multiplexing antenna in one signal reception multiplexing circuit is configured to receive and transmit the first signal, and the multiplexing antenna in the other signal reception multiplexing circuit is configured to receive and transmit the second signal. 
     In another example of an embodiment of the present disclosure, the signal reception multiplexing circuit includes one signal reception multiplexing circuit, and a multiplexing antenna in the one signal reception multiplexing circuit is also connected to a signal transmission processing circuit and a duplexer, where the signal transmission processing circuit is a first signal transmission processing circuit. The communication circuit also includes a transmission antenna and a signal transmission processing circuit connected to the transmission antenna, where the signal transmission processing circuit is a second signal transmission processing circuit. 
     In this example, when a multiplexing antenna in one signal reception multiplexing circuit is also connected to a signal transmission processing circuit and a duplexer, the signal reception multiplexing circuit may be a first signal reception multiplexing circuit and the multiplexing antenna is configured to receive and transmit the first signal. Alternatively, the signal reception multiplexing circuit may be a second signal reception multiplexing circuit and the multiplexing antenna is configured to receive and transmit the second signal. The communication circuit also includes a transmission antenna which is configured to transmit the first signal or the second signal separately. When the signal reception multiplexing circuit is the first signal reception multiplexing circuit, the transmission antenna is the second signal transmission antenna and is configured to transmit the second signal separately. When the signal reception multiplexing circuit is the second signal reception multiplexing circuit, the transmission antenna is the first signal transmission antenna and is configured to transmit the first signal separately. 
       FIG. 3  is a schematic structural diagram of a communication circuit according to an embodiment of the present disclosure. 
     In an example, as shown in  FIG. 3 , the communication circuit is applicable to an FDD system. The communication circuit includes four groups of signal reception multiplexing circuits, which include antennas  1 ,  2 ,  3  and  4 . The antennas  1 ,  2 ,  3  and  4  are configured to receive 5G signals and a second signal of the same frequency band sent by the base station, where the second signal includes at least one of 2G, 3G and 4G signals. In  FIG. 3 , the second signal being a 4G signal is taken as an example. The antenna  1  is also connected to a 4G signal transmission processing circuit  36  and a duplexer  311  and is configured to transmit 4G signals. The antenna  4  is also connected to a 5G signal transmission processing circuit  37  and a duplexer  312 , and is configured to transmit 5G signals. When band-pass filters connected to antenna  2  and antenna  3  are replaced with duplexers, the 5G and 4G transmission signals can also be switched among the antennas  1 ,  2 ,  3  and  4 , so the 5G and 4G transmission signals are not limited to the antennas  1  and  4 . The 5G signal and 4G signal received by antennas  1 - 4  are filtered by the band-pass filter  31 , the duplexer  311  and the duplexer  312 , and then enter a low noise pre-amplifier  32  for pre-amplification, so as to amplify the weak signals received by antennas, provide appropriate gain and reduce the influence of post-stage power divider  33  on the signal-to-noise ratio of the signal path. The low noise pre-amplifier shall be a low noise amplifier with low noise figure (nf&lt;1.0), high linearity and medium gain (gain 10˜12 dB). The pre-amplified 4G and 5G received signals are separated from the received signals by the power divider  33 , then distributed to the respective 4G signal adjustable gain amplifier  341  and 5G signal adjustable gain amplifier  342  for signal adjustable gain amplification, and then sent to a 4G signal demodulation module  351  and a 5G signal demodulation module  352  for signal demodulation processing after the signal amplitudes of 4G signal and 5G signal reach specific amplitudes. 4G receive (RX) 3411, 4G RX 3412, 4G RX 3413, 4G RX 3414, 5G RX 3421, 5G RX 3422, 5G RX 3423 and 5G RX 3424 represent four receiving links of the LTE system. 
     According to the embodiment of the present disclosure, the communication circuit includes at least one signal reception multiplexing circuit which includes a multiplexing antenna, a signal separation module connected to the multiplexing antenna, and a first signal demodulation module and a second signal demodulation module respectively connected to the signal separation module. The multiplexing antenna is configured to receive a first signal and a second signal having the same frequency band and send the received signals to the signal separation module. The signal separation module is configured to separate the first signal and the second signal from the received signal, send the separated first signal to the first signal demodulation module for demodulation processing, and send the separated second signal to the second signal demodulation module for demodulation processing. According to the embodiment of the present disclosure, the communication circuit integrates the receiving circuits and the antennas for the 4G and 5G signals of the same frequency band, to allow the downlink signals of 4G and 5G to share the antenna receiving and receiving amplification circuits, which solves the problems of crowded antenna space and larger circuit occupation area in the terminal, reduces the number of 4G 4×4MIMO+5G 4×4MIMO antennas from 8 to 4, greatly reduces the pressure of antenna layout, and reduces the number of antennas to help improve antenna performance. Using circuit multiplexing technology makes it possible to share antennas with the same frequency without deteriorating the noise figure of the link, which effectively reduces the layout size of 4G and 5G multimode products, simplifies the RF circuit design and antenna design and improves the user experience. 
     Embodiment II 
     According to another embodiment of the present disclosure, a communication circuit applicable to the FDD system is provided, as shown in  FIG. 4 . The communication circuit includes four groups of signal reception multiplexing circuits, which include multiplexing antennas  1 ,  2 ,  3  and  4 . The communication circuit also includes a transmission antenna  5  and a 5G signal transmission processing circuit  47  connected to the transmission antenna, where the transmission antenna is a transmission antenna for 5G signal and is configured to transmit 5G signals separately. The antennas  1 ,  2 ,  3  and  4  are configured to receive 5G signals and a second signal of the same frequency band sent by the base station, where the second signal includes at least one of 2G, 3G and 4G signals. In  FIG. 4 , the second signal being a 4G signal is taken as an example. The antenna  1  is also connected to a 4G signal transmission processing circuit  46  and a duplexer  411  and is configured to transmit 4G signals. When band-pass filters connected to the antennas  2 ,  3  and  4  are replaced with duplexers, the 4G transmission signals can also be switched among the antennas  1 ,  2 ,  3  and  4 , so the 4G transmission signals are not limited to the antenna  1 . The 5G 4G signals received by the antennas  1 - 4  are filtered by the band-pass filter  41  and the duplexer  411 , and then enter a low noise pre-amplifier  42  for pre-amplification, so as to amplify the weak signals received by antennas, provide appropriate gain and reduce the influence of post-stage power divider  43  on the signal-to-noise ratio of the signal path. The low noise pre-amplifier shall be a low noise amplifier with low noise figure (nf&lt;1.0), high linearity and medium gain (gain 10˜12 dB). The pre-amplified 4G and 5G received signals are separated from the received signals by the power divider  43 , then distributed to the respective 4G signal adjustable gain amplifier  441  and 5G signal adjustable gain amplifier  442  for signal adjustable gain amplification, and then sent to a 4G signal demodulation module  451  and a 5G signal demodulation module  452  for signal demodulation processing after the signal amplitudes of 4G signal and 5G signal reach specific amplitudes. 
     According to the embodiment of the present disclosure, the communication circuit includes at least one signal reception multiplexing circuit which includes a multiplexing antenna, a signal separation module connected to the multiplexing antenna, and a first signal demodulation module and a second signal demodulation module respectively connected to the signal separation module. The multiplexing antenna is configured to receive a first signal and a second signal having the same frequency band and send the received signals to the signal separation module. The signal separation module is configured to separate the first signal and the second signal from the received signal, send the separated first signal to the first signal demodulation module for demodulation processing, and send the separated second signal to the second signal demodulation module for demodulation processing. According to the embodiment of the present disclosure, the communication circuit integrates the receiving circuits and antennas for the 4G and 5G signals of the same frequency band, allowing the downlink signals of 4G and 5G to share the antenna receiving and receiving amplification circuits, which solves the problems of crowded antenna space and larger circuit occupation area in the terminal, reduces the number of 4G 4×4MIMO+5G 4×4MIMO antennas from 8 to 5, greatly reduces the pressure of antenna layout, and reduces the number of antennas to help improve antenna performance. Using circuit multiplexing technology makes it possible to share antennas with the same frequency without deteriorating the noise figure of the link, which effectively reduces the layout size of 4G and 5G multimode products, simplifies the RF circuit design and the antenna design and improves the user experience. 
     Embodiment III 
     According to another example of the embodiment of the present disclosure, a communication circuit applicable to the FDD system is provided, as shown in  FIG. 5 . The communication circuit includes four groups of signal reception multiplexing circuits, which include multiplexing antennas  1 ,  2 ,  3  and  4 . The communication circuit also includes a transmission antenna  5  and a 4G signal transmission processing circuit  57  connected to the transmission antenna, where the transmission antenna is a transmission antenna for 4G signal and is configured to transmit 4G signals separately. The antennas  1 ,  2 ,  3  and  4  are configured to receive 5G signals and a second signal having the same frequency band sent by the base station, where the second signal includes at least one of 2G, 3G and 4G signals. In  FIG. 5 , the second signal being a 4G signal is taken as an example. The antenna  1  is also connected to a 5G signal transmission processing circuit  56  and a duplexer  511  and is configured to transmit 5G signal. When band-pass filters connected to the antennas  2 ,  3  and  4  are replaced with duplexers, the 5G transmission signals can also be switched among the antennas  1 ,  2 ,  3  and  4 , so the 5G transmission signals are not limited to the antenna  1 . The 5G and 4G signals received by the antennas  1 - 4  are filtered by the band-pass filter  51  and the duplexer  511 , and then enter a low noise pre-amplifier  52  for pre-amplification, so as to amplify the weak signals received by antennas, provide appropriate gain and reduce the influence of post-stage power divider  53  on the signal-to-noise ratio of the signal path. The low noise pre-amplifier shall be a low noise amplifier with low noise figure (nf&lt; 1 . 0 ), high linearity and medium gain (gain 10˜12 dB). The pre-amplified 4G and 5G received signals are separated from the received signals by the power divider  53 , then distributed to the respective 4G signal adjustable gain amplifier  541  and 5G signal adjustable gain amplifier  542  for signal adjustable gain amplification, and then sent to a 4G signal demodulation module  551  and a 5G signal demodulation module  552  for signal demodulation processing after the signal amplitudes of 4G signal and 5G signal reach specific amplitudes. 
     According to the embodiment of the present disclosure, the communication circuit includes at least one signal reception multiplexing circuit which includes a multiplexing antenna, a signal separation module connected to the multiplexing antenna, and a first signal demodulation module and a second signal demodulation module respectively connected to the signal separation module. The multiplexing antenna is configured to receive a first signal and a second signal having the same frequency band and send the received signals to the signal separation module. The signal separation module is configured to separate the first signal and the second signal from the received signal, send the separated first signal to the first signal demodulation module for demodulation processing, and send the separated second signal to the second signal demodulation module for demodulation processing. According to the embodiment of the present disclosure, the communication circuit integrates the receiving circuits and antennas for the 4G and 5G signals of the same frequency band, allowing the downlink signals of 4G and 5G to share the antenna receiving and receiving amplification circuits, which solves the problems of crowded antenna space and larger circuit occupation area in the terminal device, reduces the number of 4G 4×4MIMO+5G4×4MIMO antennas from 8 to 5, greatly reduces the pressure of antenna layout, and reduces the number of antennas to help improve antenna performance. Using circuit multiplexing technology makes it possible to share antennas with the same frequency without deteriorating the noise figure of the link, which effectively reduces the layout size of 4G and 5G multimode products, simplifies the RF circuit design and antenna design and improves the user experience. 
     Embodiment IV 
     According to another example of the embodiment of the present disclosure, a communication circuit applicable to the FDD system and a TDD system is provided, as shown in  FIG. 6 . The communication circuit includes four groups of signal reception multiplexing circuits, which include multiplexing antennas  1 ,  2 ,  3  and  4 . The communication circuit also includes a transmission antenna  5 , a transmission antenna  6 , a 4G signal transmission processing circuit  66  connected to the transmission antenna  5 , and a 5G signal transmission processing circuit  67  connected to the transmission antenna  6 , where the transmission antenna  5  is a transmission antenna for 4G signal and is configured to transmit 4G signals separately; and the transmission antenna  6  is a transmission antenna for 5G signal and is configured to transmit 5G signals separately. The antennas  1 ,  2 ,  3  and  4  are configured to receive 5G signals and a second signal having the same frequency band sent by the base station, where the second signal includes at least one of 2G, 3G and 4G signals. In  FIG. 6 , the second signal being a 4G signal is taken as an example. The 5G and 4G signals received by the antennas  1 - 4  are filtered by the band-pass filter  61 , and then enter a low noise pre-amplifier  62  for pre-amplification, so as to amplify the weak signals received by antennas, provide appropriate gain and reduce the influence of post-stage power divider  63  on the signal-to-noise ratio of the signal path. The low noise pre-amplifier shall be a low noise amplifier with low noise figure (nf&lt;1.0), high linearity and medium gain (gain 10˜12 dB). The pre-amplified 4G/5G received signals are separated from the received signals by the power divider  63 , then distributed to the respective 4G signal adjustable gain amplifier  641  and 5G signal adjustable gain amplifier  642  for signal adjustable gain amplification, and then sent to a 4G signal demodulation module  651  and a 5G signal demodulation module  652  for signal demodulation processing after the signal amplitudes of 4G signal and 5G signal reach specific amplitudes. 
     According to an embodiment of the present disclosure, a communication device is also provided, which includes the communication circuit described in the above embodiments. 
     In an embodiment of the present disclosure, the communication device may be a user device or a base station. 
     According to the embodiment of the present disclosure, the communication circuit includes at least one signal reception multiplexing circuit which includes a multiplexing antenna, a signal separation module connected to the multiplexing antenna, and a first signal demodulation module and a second signal demodulation module respectively connected to the signal separation module. The multiplexing antenna is configured to receive a first signal and a second signal having the same frequency band and send the received signals to the signal separation module. The signal separation module is configured to separate the first signal and the second signal from the received signal, send the separated first signal to the first signal demodulation module for demodulation processing, and send the separated second signal to the second signal demodulation module for demodulation processing. According to the embodiment of the present disclosure, the communication circuit integrates the receiving circuits and antennas for the 4G and 5G signals of the same frequency band, allowing the downlink signals of 4G and 5G to share the antenna receiving and receiving amplification circuits, which solves the problems of crowded antenna space and larger circuit occupation area in the terminal, reduces the number of 4G 4×4MIMO+5G 4×4MIMO antennas from 8 to 6, greatly reduces the pressure of antenna layout, and reduces the number of antennas to help improve antenna performance. Using circuit multiplexing technology makes it possible to share antennas with the same frequency without deteriorating the noise figure of the link, which effectively reduces the layout size of 4G and 5G multimode products, simplifies the RF circuit design and antenna design and improves the user experience. 
     All or some of the steps in the methods, systems, and functional modules/units in the devices disclosed above may be implemented as software (which may be implemented with computer program code executable by the computing device), firmware, hardware and appropriate combinations thereof. In the hardware implementation, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components. For example, a physical component may have multiple functions, or a function or step may be cooperatively performed by multiple physical components. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. 
     Communication medium typically contains computer-readable instructions, data structures, computer program modules, or other data in modulated data signals such as carriers or other transmission mechanisms, and may include any information delivery medium. Therefore, the present disclosure is not limited to any specific combination of hardware and software.