Wireless communication system of intelligent meter

Abstract

The utility model provides a wireless communication system of an intelligent meter. The wireless communication system comprises an antenna, a harmonic filtering module, a radio frequency front-end module, a conditioning and frequency selecting module, a transceiving modem and a main control module which are connected in sequence, the antenna is in wireless communication connection with handheld equipment; the conditioning and frequency-selecting module comprises a frequency-selecting chip and a signal conditioning unit; the signal conditioning unit comprises a first diode and a second diode which are reversely connected in parallel; the output end of the radio frequency front end module is connected with the input end of the frequency selection chip; the output end of the frequency-selecting chip is connected with the transceiving modem; the anode of the first diode is connected with the ground, and the cathode of the first diode is connected between the output end of the radio frequency front end module and the input end of the frequency selection chip. According to the utility model, the synchronization of wireless data transmission stability and transmission distance can be obviously improved, and the number of network transmission relay devices can be reduced.

Description

Technical Field

[0001] This utility model relates to the field of smart meter technology, and more specifically to a wireless communication system for smart meters. Background Technology

[0002] With the advancement of global intelligence, more and more electronic devices are ubiquitous, creating an interconnected world, and wireless communication plays a crucial role in this. Given limited spectrum resources, the ISM band, as an unlicensed band, is the most active. Currently, many short-range, low-power communication systems operate in this band. For example, 430.050-434.790MHz is allocated for amateur radio use, used for small telephones, wireless headsets, remote control and telemetry, and walkie-talkies; the 863-870MHz band is where LoRaWAN wireless gateways and their network nodes operate. These products using the ISM band constantly face interference from other radio frequency and microwave technologies, significantly impacting communication distance and stability. This is especially true for products closely related to people's lives, such as smart meters and wireless meter reading systems, which also use the ISM band for wireless data communication. With the increasing number of network nodes and the complex urban environment, communication distances vary considerably, and communication stability is deteriorating, requiring dense deployment of repeaters or concentrators to ensure network quality in wireless communication systems.

[0003] To reduce the deployment cost of electricity meter networks, improving communication stability and range has become crucial. The most common method to increase communication range is to increase transmit power and improve receiver sensitivity. However, while the ISM unlicensed band shares spectrum resources, radio regulatory commissions in various countries have limited the maximum transmit power of equipment to reduce signal radiation to the human body and to minimize interference between devices; furthermore, increased transmit power places higher demands on equipment power consumption. In addition, from the perspective of the equipment system, receiver sensitivity is theoretically fixed due to limitations imposed by white noise, modulation methods, and the amount of communication data, making improvement extremely difficult.

[0004] For smart meters, since they are powered by mains electricity and the communication module is placed inside the structural cavity, they are subject to internal interference from AC to DC power conversion, relay switches, various metering modules, and the main control quartz crystal. Moreover, most meters are installed near residential buildings, and external interference from other wireless communication devices in the home is unavoidable. All these interferences restrict the communication distance and communication stability. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a wireless communication system for smart meters that can improve the stability of wireless communication.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0007] A wireless communication system for a smart meter includes an antenna, a harmonic filter module, a radio frequency front-end module, a conditioning and frequency selection module, a transceiver modem, and a main control module connected in sequence; the antenna is wirelessly connected to a handheld device.

[0008] The conditioning and frequency selection module includes a frequency selection chip and a signal conditioning unit; the signal conditioning unit includes a first diode and a second diode connected in reverse parallel; the output terminal of the RF front-end module is connected to the input terminal of the frequency selection chip; the output terminal of the frequency selection chip is connected to the transceiver modem; the anode of the first diode is grounded, and its cathode is connected between the output terminal of the RF front-end module and the input terminal of the frequency selection chip.

[0009] Optionally, it further includes: a transmit matching and link gain control module; the transmit matching and link gain control module is connected to the radio frequency front-end module and the transceiver modem respectively.

[0010] Optionally, it also includes a power module and an interface module; the power module and the interface module are respectively connected to the main control module.

[0011] Optionally, the radio frequency front-end module includes a power amplifier (PA), a radio frequency switch, and a low noise amplifier (LNA); the antenna is connected to the power amplifier (PA) and the low noise amplifier (LNA) respectively through the radio frequency switch; the power amplifier (PA) and the low noise amplifier (LNA) are respectively connected to the transceiver modem.

[0012] Optionally, the receiving modes of the low-noise amplifier (LNA) include a receive LNA mode and a receive bypass mode.

[0013] Optionally, the conditioning and frequency selection module further includes three capacitors; the output terminal of the RF front-end module is connected to the input terminal of the frequency selection chip through two capacitors connected in series; the two capacitors connected in series are grounded through the signal conditioning unit; and the output terminal of the frequency selection chip is connected to the transceiver modem through a capacitor.

[0014] Optionally, the frequency selection chip is model HDF869A2-P2.

[0015] The beneficial effects of this invention are as follows: The wireless communication system of this invention periodically collects all surrounding wireless signals through the radio frequency front-end module in the system idle state, filters out unsupported frequency bands through the conditioning and frequency selection module, determines the signal strength and frequency point through the transceiver modem, and obtains a periodically updated channel list. The main control module determines whether the strength of all channels in the channel list is lower than a preset first strength threshold. If so, the channel list is locked for communication; otherwise, the channel with the lowest signal strength is locked for communication. This achieves the screening and frequency locking of clean channels before communication is established, ensuring a longer transmission distance during the handshake request process. Simultaneously, by adding a frequency selection chip and a signal conditioning unit to the conditioning and frequency selection module between the radio frequency front-end module and the transceiver modem, the signal strength input to the transceiver modem is strictly controlled within a certain range, thereby ensuring the safety and reliability of the transceiver modem chip. This invention can improve the wireless transmission stability of the wireless communication system. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the composition and connection of a wireless communication system provided in an embodiment of the present invention.

[0017] Figure 2 A schematic diagram of the structure of the conditioning and frequency selection module in the wireless communication system provided in the embodiment of this utility model;

[0018] Figure 3 A schematic diagram of the limiting characteristic curve of the signal conditioning unit in the wireless communication system provided for the implementation of this utility model;

[0019] Figure 4 A schematic diagram of the circuit structure of the antenna + harmonic filter module + radio frequency front-end module in the wireless communication system provided for the implementation of this utility model;

[0020] Figure 5 A schematic diagram of the integrated structure of the radio frequency front-end module in the wireless communication system provided for the implementation of this utility model;

[0021] Figure 6 A schematic diagram of the transceiver modem in the wireless communication system provided for the implementation of this utility model;

[0022] Figure 7 A schematic diagram of the circuit structure of a transceiver modem in a wireless communication system provided for the implementation of this utility model;

[0023] Figure 8 A schematic diagram of the circuit structure of the main control module in the wireless communication system provided for the implementation of this utility model.

[0024] Label Explanation:

[0025] 1. Antenna; 2. Harmonic filtering module; 3. RF front-end module; 4. Conditioning and frequency selection module;

[0026] 5. Transceiver modem; 6. Main control module; 7. Transmit matching and link gain control module;

[0027] 8. Power supply module; 9. Interface module. Detailed Implementation

[0028] To illustrate in detail the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this utility model, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this utility model and are therefore intended to limit the scope of protection of this utility model.

[0029] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0030] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0031] In the description of this utility model, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " generally indicates that the preceding and following objects have an "or" logical relationship.

[0032] In this invention, terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy, or order between these entities or operations.

[0033] Without further limitations, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this invention is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a series of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0034] Similar to the understanding in the Examination Guidelines, in this utility model, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments of this utility model, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0035] In the description of the embodiments of this utility model, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the convenience of describing the specific embodiments of this utility model or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model.

[0036] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this utility model, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this utility model pertains, the specific meaning of the above terms in the embodiments of this utility model can be understood according to the specific circumstances.

[0037] Please refer to Figure 1 and Figure 2 Embodiment 1 of this utility model is as follows:

[0038] This embodiment provides a wireless communication system for a smart meter, such as... Figure 1 As shown, it includes, in sequence, an antenna 1, a harmonic filtering module 2, an RF front-end module 3, a conditioning and frequency selection module 4, a transceiver modem 5, and a main control module 6; the antenna 1 is connected to the handheld device ( Figure 1 Wireless communication connection (not shown);

[0039] In this embodiment, the radio frequency front-end module is configured to periodically collect all surrounding wireless signals in an idle receiving state. Here, the idle receiving state refers to the state before the wireless communication system and the handheld device establish a communication connection and begin data interaction. At this time, the wireless communication system remains in an idle receiving state.

[0040] It is understood that a wireless communication system, in its idle receiving state, can receive interference signals and clutter from nearby sources. Simultaneously, a wireless communication system specifically designed for smart meters possesses a unique analog-to-digital conversion function, enabling it to acquire the signal strength of wireless signals through analog-to-digital conversion. Therefore, the wireless communication system of this embodiment can periodically acquire all surrounding wireless signals and obtain a channel list corresponding to each acquisition cycle.

[0041] Preferably, based on data storage optimization considerations, the channel list is stored using an iterative update method. That is, the channel list corresponding to the latest acquisition period will replace the channel list of the previous acquisition period.

[0042] The conditioning and frequency selection module is configured to filter out wireless signals in frequency bands not supported by the wireless communication system and send the filtered wireless signals to the transceiver modem.

[0043] The transceiver modem is configured to determine the frequency point and signal strength of the corresponding channel based on the wireless signal sent by the conditioning and frequency selection module, and obtain a periodically updated channel list.

[0044] The main control module is configured to determine whether the strength of all channels in the channel list for the current period is lower than a first strength threshold; if so, it locks the use of wireless signals in the channel list for communication; if not, it sorts the channels in the channel list according to the signal strength, obtains a channel strength list, and locks the use of the channel with the lowest signal strength in the channel strength list for communication.

[0045] In some specific implementations, such as Figure 1 As shown, the wireless communication system further includes a transmit matching and link gain control module 7; the transmit matching and link gain control module 7 is connected to the radio frequency front-end module 3 and the transceiver modem 5 respectively.

[0046] Here, the transmit matching and link gain control module is configured to enhance the signal amplitude or power of the signal to be transmitted before sending it to the radio frequency front-end module to control the transmission.

[0047] In some specific implementations, such as Figure 1 As shown, the wireless communication system also includes a power supply module 8 and an interface module 9; the power supply module 8 and the interface module 9 are respectively connected to the main control module 6.

[0048] Here, the power module is configured to provide power to the components within the wireless communication system, ensuring that each component operates normally; the interface module is configured to provide access for other devices.

[0049] The working principle of the wireless communication system for the smart meter provided in this embodiment is as follows:

[0050] In idle receiving mode, all surrounding wireless signals are periodically collected to obtain a periodically updated channel list; it is determined whether the strength of all channels in the channel list corresponding to the current period is lower than a first strength threshold; if so, the wireless signals in the channel list are locked for communication; if not, the channels in the channel list are sorted according to signal strength to obtain a channel strength list, and the channel with the lowest signal strength in the channel strength list is locked for communication.

[0051] The wireless communication system provided in this embodiment features a simple structure. Furthermore, through the collaborative functions of its various modules, it can collect surrounding spectrum and signal strength before communication begins, perform analog-to-digital conversion to determine a clean channel and perform frequency locking, and directly establish a communication connection with the handheld device using the clean channel when initiating a handshake request. This significantly increases the communication distance, ensuring longer transmission distances; consequently, it achieves higher communication stability, higher transmission quality, and stronger communication reliability.

[0052] Specifically, the conditioning and frequency selection module described in this embodiment, such as Figure 2 As shown, it includes a frequency selection chip U1 and a signal conditioning unit; the signal conditioning unit includes a first diode and a second diode connected in reverse parallel (i.e., Figure 2 The D1 component shown is used; the output of the RF front-end module is connected to the input of the frequency selection chip; the output of the frequency selection chip is connected to the transceiver modem; the anode of the first diode is grounded, and its cathode is connected between the output of the RF front-end module and the input of the frequency selection chip.

[0053] In some specific implementations, such as Figure 2As shown, the conditioning and frequency selection module also includes three capacitors; the output terminal of the RF front-end module is connected to the input terminal of the frequency selection chip through two capacitors connected in series; the two capacitors connected in series are grounded through the signal conditioning unit; the output terminal of the frequency selection chip is connected to the transceiver modem through a capacitor.

[0054] In some specific examples, the frequency selection chip can be implemented using a frequency selection chip of model HDF869A2-P2.

[0055] The limiting characteristic curve of the signal conditioning unit is as follows: Figure 3 As shown, when the input signal strength is below 10dBm, the input and output are positively correlated, and the signal conditioning unit does not operate. When the input signal strength is above 10dBm, the signal conditioning unit starts to operate and adjust the output signal amplitude. When the input signal amplitude reaches 28dBm, the output signal is conditioned to the maximum value of 17dBm. Thereafter, no matter how much the input signal increases, the output signal is controlled below 17dBm. That is, the input signal strength of the transceiver modem chip's RFIP pin is strictly controlled within 17dBm, thereby ensuring that the transceiver modem chip will not cause channel blockage or even burn out due to excessive input signal.

[0056] Combination Figure 2 and Figure 3 The working principle of the conditioning and frequency selection module is as follows:

[0057] The signal transmitted from the RF front-end module is filtered by the conditioning and frequency selection module to remove signals outside the frequency band supported by the wireless communication system, and the selected signal within the frequency band is sent to the RFIP pin of the transceiver modem. Furthermore, when the handheld device is very close to the wireless communication system, the power transmitted by the handheld device, after being amplified by the LNA in the RF front-end module, may result in a signal strength at the RFIP pin of the transceiver modem chip exceeding the maximum receiveable signal strength of 17dBm, potentially causing channel congestion or burning out the transceiver modem chip. Therefore, by adding a signal conditioning unit between the RF front-end module and the transceiver modem, and using a single-phase limiting diode selected by the signal conditioning unit to achieve amplitude limiting and suppression, the input signal strength of the transceiver modem chip's RFIP pin is strictly controlled within 17dBm, thereby ensuring the safety and reliability of the transceiver modem chip and improving the wireless communication stability of the wireless communication system in the smart instrument.

[0058] Please refer to Figure 4 and Figure 5 Embodiment two of this utility model is as follows:

[0059] This embodiment is a further extension of Embodiment 1, specifically optimizing the radio frequency front-end portion to further improve the stability of wireless communication.

[0060] The circuit structure of the antenna + harmonic filter module + RF front-end module in the wireless communication system of this embodiment is as follows: Figure 4 As shown. Specifically, the RF front-end module includes a power amplifier (PA), an RF switch, and a low-noise amplifier (LNA). Preferably, as... Figure 5 As shown, the power amplifier (PA), RF switch, and low-noise amplifier (LNA) are integrated into a single IC device. It can be understood that the antenna is connected to the power amplifier (PA) and the low-noise amplifier (LNA) respectively via the RF switch; the power amplifier (PA) and the low-noise amplifier (LNA) are respectively connected to the transceiver modem.

[0061] The low-noise amplifier (LNA) has two reception modes: a receive LNA mode and a receive bypass mode. In this embodiment, the LNA is configured to operate in receive LNA mode by default, and to switch to receive bypass mode when the received signal strength is determined to be higher than a second strength threshold.

[0062] based on Figure 5 The integrated structure of the low-noise amplifier (LNA) allows switching between different operating modes by enabling the CSD, CTX, and CPS pin levels. The switching logic is shown in Table 1 below:

[0063]

[0064]

[0065] Table 1

[0066] Combination Figure 4 and Figure 5 The working principle of the RF front-end module is explained as follows:

[0067] In the idle receiving state of the wireless communication system, Figure 5 In the RF front-end module shown, the CSD pin is set to high level by default and the CTX pin is set to low level, so that the RF front-end module can work in LNA receiving mode; Figure 4 The antenna J600 shown receives all interference signals and clutter in the environment near the wireless communication system. After the high-frequency signal amplitude is suppressed by the harmonic filtering module, it is input to pin 9 of U600 in the RF front-end module. The interference signals and clutter are then sent to the low-noise amplifier (LNA) of the RF front-end module. After processing by the LNA, they are output to the conditioning and frequency selection module.

[0068] When the received signal strength is below -10dBm, the RF front-end module operates in receive LNA mode based on the control logic in Table 1. At this time, although the received signal is amplified, it can still remain within the dynamic demodulation range of the transceiver modem.

[0069] When the received signal strength is higher than -10dBm, the RF front-end module operates in receive bypass mode based on the control logic in Table 1, that is, the received signal will not be amplified, and the received signal will be controlled within the dynamic demodulation range of the transceiver modem.

[0070] The LNA receiving mode mentioned above refers to the normal operating mode of the radio frequency receiver, which amplifies the received weak signal through the LNA while minimizing the introduction of noise, improving receiving sensitivity and signal quality, and ensuring that even weak signals can be accurately demodulated.

[0071] The aforementioned receiver bypass mode refers to a special operating mode of the radio frequency receiver. By bypassing the LNA to directly process the signal and instead using bypass transmission, it can avoid the introduction of additional noise by the LNA and reduce the impact of noise.

[0072] It is understandable that when the signal strength is too strong and exceeds the dynamic demodulation range of the transceiver modem, the signal will be distorted.

[0073] In this embodiment, the second strength threshold, i.e., a signal strength comparison threshold value, can be selected as -10dBm, is preset in the radio frequency front-end module; this is used as the basis for determining whether the signal strength is too strong.

[0074] When the received signal strength is lower than the second strength threshold, it means that the received signal is not too strong. The RF front end will control the operation to operate in the receive LNA mode, which can amplify the signal as much as possible, and it is all within the dynamic adjustment range of the transceiver modem, so that the signal can be accurately demodulated.

[0075] When the received signal strength exceeds the second strength threshold, it indicates that the received signal is too strong. If the LNA mode is still used, the LNA will introduce additional noise, interfering with the signal and degrading signal quality. Therefore, by switching the RF front-end to receive bypass mode, additional noise can be avoided when the signal strength is too strong. In this case, the received signal does not need to be amplified and remains within the dynamic adjustment range of the transceiver modem, enabling accurate signal demodulation.

[0076] As can be seen from the above, this embodiment optimizes the radio frequency front-end of the wireless communication system, enabling it to judge the current received signal strength in real time during communication and dynamically switch different working modes accordingly to effectively avoid channel congestion and signal distortion caused by excessively strong received signal amplitude, thus ensuring communication stability and reliability.

[0077] Example 3

[0078] This embodiment is a further extension of Embodiment 1 or Embodiment 2, and further refines the constituent modules of the wireless communication system.

[0079] The transceiver modem structure in the wireless communication system of this embodiment is as follows: Figure 6 As shown, its circuit structure is as follows Figure 7 As shown.

[0080] Combination Figure 6 and Figure 7 The working principle of the transceiver modem is as follows:

[0081] After receiving the signal sent by the conditioning and frequency selection module through the RFIP pin, the transceiver modem will perform signal amplification, mixing, smoothing filtering, and analog-to-digital conversion inside the transceiver modem to obtain the frequency points and signal strength information of all channels. The transceiver modem reads the frequency points and signal strength information of all channels and sends them to the main control module through the SPI interface.

[0082] The circuit structure of the main control module in the wireless communication system of this embodiment is as follows: Figure 8 As shown.

[0083] Combination Figure 8 The working principle of the main control module is as follows:

[0084] Figure 8 The main control module shown is Figure 7 The transceiver modem shown is connected via an SPI interface. The transceiver modem demodulates the input signal and converts it into a digital signal, which is then transmitted via RF-SI, RF-SO, RF-CLK, and RF-CS (i.e.,...). Figure 8 Pins 50, 49, 51, and 48 of the U502 device are connected to the main control chip U502 of the main control module. The internal memory of the main control chip U502 is pre-set with a comparison threshold of -75dBm, which is the first strength threshold. The signal strength sent from the conditioning and frequency selection module is compared with the first strength threshold. The judgment process is as follows:

[0085] 1. If the signal strength of all channels is less than -75dBm, it means that all channels are clean channels. At this time, the main control module sends a command to the transceiver modem to lock the current channel list for communication.

[0086] 2. If the signal strength of all channels is greater than -75dBm, it indicates that a channel is being interfered with. In this case, the main control module sorts all channel signals according to their strength, selects the channel with the lowest signal strength, and sends a command to the transceiver modem to lock the channel with the lowest signal strength for communication.

[0087] Based on the aforementioned wireless communication system architecture, when communicating with a handheld device, a handshake request command will be initiated using a locked clean channel. After a successful handshake, the channel will be locked for normal data exchange. This ensures that the smart meter's wireless communication system always uses a clean channel to interact with the handheld device, guaranteeing both longer transmission distances and stable and reliable communication over those distances.

[0088] In summary, the wireless communication system for smart meters provided by this utility model, without increasing transmission power, transmission power consumption, or receiving sensitivity, achieves a significant improvement in wireless data transmission stability and transmission distance by focusing on circuit structure and transceiver logic. This is achieved through a series of technical means, including frequency sweep interference selection of the optimal channel, control of the received signal strength within the optimal dynamic range, and control of the input signal strength of the transceiver modem. This also reduces the number of network transmission relay devices required.

[0089] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent modifications made based on the content of this utility model specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A wireless communication system for a smart meter, characterized by The application relates to a handheld device, which comprises an antenna, a harmonic filter module, a radio frequency front end module, a conditioning and frequency selection module, a transceiver modem and a main control module connected in sequence; the antenna is connected with a handheld device in wireless communication mode; The conditioning and frequency selection module comprises a frequency selection chip and a signal conditioning unit; the signal conditioning unit comprises a first diode and a second diode connected in reverse parallel mode; The output end of the radio frequency front end module is connected with the input end of the frequency selection chip; the output end of the frequency selection chip is connected with the transceiver modem; the anode of the first diode is grounded, and the cathode is connected between the output end of the radio frequency front end module and the input end of the frequency selection chip.

2. A wireless communication system of an intelligent meter according to claim 1, wherein, Further comprising: a transmitting matching and link gain control module; the transmitting matching and link gain control module is connected with the radio frequency front end module and the transceiver modem respectively.

3. A wireless communication system of an intelligent meter according to claim 1, wherein, Further comprising a power module and an interface module; the power module and the interface module are connected with the main control module respectively.

4. A wireless communication system of an intelligent meter according to claim 1, wherein, The radio frequency front end module comprises a power amplifier PA, a radio frequency switch and a low noise amplifier LNA; the antenna is connected with the power amplifier PA and the low noise amplifier LNA through the radio frequency switch respectively; the power amplifier PA and the low noise amplifier LNA are connected with the transceiver modem respectively.

5. A wireless communication system of an intelligent meter according to claim 4, wherein, The receiving mode of the low noise amplifier LNA comprises a receiving LNA mode and a receiving bypass mode.

6. A wireless communication system of an intelligent meter according to claim 1, wherein, The conditioning and frequency selection module further comprises three capacitors; the output end of the radio frequency front end module is connected with the input end of the frequency selection chip through two series-connected capacitors; the two series-connected capacitors are connected with the signal conditioning unit in ground connection mode; the output end of the frequency selection chip is connected with the transceiver modem through a capacitor.

7. A wireless communication system of an intelligent meter according to claim 6, wherein, The model of the frequency selection chip is HDF869A2-P2.

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