Wired communication system replacing in-vehicle CAN / LIN bus

Abstract

To provide a cable communication system instead of an on-vehicle CAN (controller area network) / LIN (local interconnection network) bass.SOLUTION: A cable communication system comprises: an electric power line or a transmission line that is connected to a plurality of communication units; and a master communication unit. In a first time region, each of the plurality of communication units includes a dedicated transmission frequency band, and the transmission frequency band of the plurality of communication units is not overlapped with each other, and is not overlapped to the transmission frequency band of the master communication unit or a transmission time. All of the transmission frequency bands can be coupled to a complete OFDM frequency band width, and has no guard band in the transmission frequency band.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a new wired communication system that replaces CAN / LIN bus-based architectures in vehicles, reducing costs and improving the feasibility of automated production. The related method is also applicable to wired communication applications such as in-vehicle power lines, twisted pairs, and coaxial cables. [Background technology]

[0002] Currently, most of the Internet of Things circuits inside vehicles are wired using Controller Area Networks (CAN) and Local Interconnect Networks (LIN), which connect with other terminal control lines to complete vehicle monitoring and communication. These wiring harnesses are expensive, increase the vehicle's weight, reduce the available space inside the vehicle, and make automated assembly and online upgrades difficult. Therefore, using on-board power lines and fewer wiring harnesses as the on-board transmission lines for in-vehicle communication has the advantages of reducing costs, reducing the overall system weight, increasing the available space inside the vehicle, and facilitating vehicle software upgrades and automated production.

[0003] Existing PLC (Power Line Communication) protocols, such as G3-PLC (Generation 3 PLC), HPLC (High-speed PLC), and Homplug AV / GreenPhy communication modes, all use a fixed frequency band for transmission, meaning that only one of the many communication units on the same transmission line can transmit a signal at a time. Otherwise, a so-called signal "collision" occurs, resulting in a signal error and the need for retransmission. In other words, existing PLC communication modes cannot guarantee that signal transmission will be successful exactly once; there is a possibility of errors occurring, and the time until transmission is successfully completed cannot be guaranteed. In-vehicle communication typically requires immediacy and reliability, so existing PLC communication protocols are not well suited to completing transmissions in place of the highly reliable CAN / LIN.

[0004] To avoid collisions, conventional techniques often use frequency division multiplexing (FDM) to divide the available frequency range into several frequency bands. To prevent signals from interfering with each other, guard bands must be placed between adjacent frequency bands to avoid interference and ensure separation between them. However, this method requires discarding some frequency bands to use as guard bands. Further subdividing the frequency band results in a significant discarded frequency band, resulting in underutilization of the precious, limited communication spectrum. Furthermore, to achieve better reception, various analog and digital filters are added to the hardware design of the communication unit for each frequency band, increasing system costs and power consumption. Summary of the Invention

[0005] To ensure sufficient frequency bandwidth for each communication unit in the vehicle, a fixed operating frequency band can be assigned to each communication unit. Compared with a conventional FDM device, the present invention does not require guard bands or additional filters to complete frequency band division. Furthermore, unlike a conventional FDM device that demodulates only its own dedicated frequency band, the present invention demodulates the frequency band used by all communication units, and packets transmitted by all communication units have the same length. The present invention discloses a wired communication system that replaces an in-vehicle CAN / LIN bus. The wired communication system has a power line or transmission line connected to multiple communication units (in one embodiment, wires such as twisted pair or coaxial cable can be used instead of power lines to improve communication quality). The wired communication system includes a master communication unit that corrects the time delay or attenuation values ​​of the multiple communication units and completes clock correction. The master communication unit performs time synchronization with the multiple communication units, assigns multiple transmission frequency bands to be used by the multiple communication units, and adjusts the transmission energy of the multiple communication units so that the transmission energy of the multiple communication units is appropriately or correspondingly compensated for the attenuation of the multiple transmission frequency bands. In some cases, attenuation compensation can also be achieved by compensation on the receiver side.

[0006] In one embodiment of the present invention, the master communication unit assigns the communication units such that the communication units have uplink or downlink times corresponding to the transmission frequency bands.

[0007] In one embodiment of the present invention, when the time delay and the attenuation value are greater than a critical value, after the master communication unit allocates the uplink time of the plurality of communication units corresponding to the transmission frequency band, the plurality of communication units simultaneously transmit packets to the master communication unit, and the master communication unit forwards the packets to the plurality of target communication units, and the master communication unit adjusts the transmission time of each communication unit and corrects the clock to improve packet synchronization when the packets of each communication unit are transmitted to the master communication unit, or corrects the angle of each frequency band at the receiving side in the system to achieve a better demodulation effect.

[0008] In one embodiment of the present invention, the master communication unit enables the communication units to pre-compensate the signal energy of the packets before transmitting them based on the positions or signal attenuation values ​​of the communication units on the power line, so that when the target communication units receive the packets, the signal energy in all of the transmission frequency bands is approximately the same.Furthermore, some or all of the compensation can be completed at the receiving end of the system to demodulate the correct signal content.

[0009] In one embodiment of the present invention, in order to reduce costs, some communication units can transmit and receive fewer orthogonal frequency-division multiplexing (OFDM) subcarriers or can carry fewer bits at each frequency point. The placement of a master communication unit allows different communication units to be mixed throughout the system, thereby reducing the overall system cost. [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows a schematic diagram of a transmission line (non-power line) embodiment of the present invention. [Figure 2]1 shows a schematic diagram of a wired communication system 100 of the present invention at the initial start-up stage. [Figure 3] 1 shows the frequency bands allocated to communication units 201-2016 within the total communication band in a 64 subcarrier OFDM embodiment, each frequency band having four subcarriers. [Figure 4A] 4 shows a wired communication system 400A as an alternative to an in-vehicle CAN / LIN bus according to the present invention. [Figure 4B] 4 shows a wired communication system 400B as an alternative to an in-vehicle CAN / LIN bus according to the present invention. [Figure 4C] A schematic diagram of an active isolator 403 is shown. [Figure 5] 1 illustrates one embodiment of a transceiver circuit for a communication unit 20N. [Figure 6] 1 illustrates one embodiment of the present invention. [Figure 7] 1 illustrates one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] This invention discloses several architectures that can be used for wired communication in a vehicle (wires such as twisted pair or coaxial cable are also applicable. In this case, the wires do not serve as a power source or are not connected to a battery, but are used purely for communication.) This architecture is suitable for transmission line applications with short distances, low noise, and small changes in line impedance.

[0012] Please refer to Fig. 1. Fig. 1 shows a schematic diagram of one embodiment of the present invention. The present invention discloses a wired communication system 100 that replaces an in-vehicle CAN / LIN bus. The wired communication system 100 includes a master communication unit 1 and a plurality of application modules 101 to 10N, each of which has a corresponding communication unit 201 to 20N. The wired communication system 100 includes a transmission line connected to the communication units 201 to 20N. The wired communication system 100 is a non-power line communication system.

[0013] In the present invention, the communication units 201-20N can transmit different frequency bands to prevent signal "collisions." In one embodiment, the communication units 201-20N are assigned different transmission frequency bands B1-BN, so there is no problem with signal collisions in the present invention.

[0014] In one embodiment, assuming that the wired communication system 100 is currently in a first time domain, if the length of the power line or transmission line is shorter than the wavelength of the transmission signal frequency band, and the attenuation and delay of the signal received at any point on the power line or transmission line are very similar, e.g., below a critical value, the system can be considered the same OFDM system. However, the frequency band that each communication unit can transmit is configured with specific non-overlapping subcarriers. The system only needs to synchronize the time and packet length of each communication unit's signal transmission, allowing each communication unit to simultaneously transmit signals in its own dedicated frequency band and simultaneously receive signals from all communication units and demodulate packets. That is, the transmission frequency bands of these communication units do not overlap with each other and do not overlap with the transmission frequency band or transmission time of the master communication unit. All of the transmission frequency bands can be combined into the complete OFDM frequency band, with no guard bands between the transmission frequency bands. In such a system, each communication module can demodulate the content transmitted by other communication units, making the communication mode "many-to-many." If the message specifies a specific recipient, the receiver recognizes the message and can take appropriate action. Because all messages are demodulated, each communication unit can learn the content of messages exchanged between other communication units. This feature makes it a highly efficient message transmission method for highly intelligent autonomous driving systems, allowing any operational unit to instantly grasp messages from other sensors and learn the ongoing responses of other operational units. To illustrate this with a simple example, consider an OFDM system with 64 subcarriers. As shown in Figure 3, there are 16 communication units 201-2016 on the same power line that can communicate with each other. Each communication unit is assigned a dedicated frequency band of four subcarriers for transmitting signals, allowing each communication unit to simultaneously transmit signals to other communication units using its own dedicated frequency band.For example, within a specific packet time, communication units 201, 205, 2010, and 2016 all transmit packets, and communication units 201 and 205 transmit packets to communication unit 208, communication unit 2010 transmits packets to communication unit 2016, which then broadcasts the packets to all other communication units. After all communication units receive and demodulate the packets, communication unit 208 receives packets from communication units 201 and 205, and communication unit 2016 receives messages from communication unit 2010. Also, communication units 201-2015 all receive packets from communication unit 2016. Because each communication unit demodulates all packets output onto the power line, each communication unit can see all packets exchanged between them. In this case, the master communication unit may be any one of the communication units 201-2016, which is responsible for coordinating the start of communication, and during communication, each communication unit 201-2016 can transmit and receive signals synchronously.

[0015] To maintain a high overall transmission rate over the power line, each communication unit 201-20N can simultaneously transmit and receive signals. However, to prevent signals transmitted by different communication units 201-20N from becoming noise for other communication units 201-20N, the start and end times of packets transmitted by each communication unit 201-20N must be synchronized during demodulation at the receiving end so that the correct packets can be demodulated. That is, the system of the present invention requires a synchronization process after startup, and this synchronization must be maintained during normal operation, with appropriate fine adjustments continuously made to compensate for the effects of external factors such as temperature and humidity. That is, the master communication unit must synchronize all communication units with its own clock. The master communication unit and the communication units simultaneously transmit packets of the same length, ensuring that all signals can be demodulated by each communication unit and the master communication unit.

[0016] If the length of the transmission line is not short enough relative to the wavelength of the communication frequency band, the time delay between signals transmitted between different communication units may be significant, resulting in each communication unit being unable to correctly decode all OFDM signals. This is because the difference in signal arrival times can cause signal distortion or interference, affecting the demodulation results. In this case, only the second transmission mode can be adopted. That is, all communication units perform delay and attenuation compensation only with respect to the master communication unit. Each communication unit still has its own dedicated transmission frequency band and transmits signals synchronously with the compensated time difference, but all communication units send messages to the master communication unit, i.e., a "one-to-many" communication mode. In this case, communication units farther from the master communication unit start transmitting packets earlier, while communication units closer to the master communication unit start transmitting packets later. After the compensation, the OFDM signals received by the master communication unit appear as if each transmission frequency band was being transmitted simultaneously from a specific communication unit, allowing for smooth demodulation. In other words, the master communication unit adjusts the transmitting side of all communication units in the system to perform time delay compensation, so that when packets transmitted from each communication unit arrive at the master communication unit, all packets can be combined into a complete OFDM signal. Message transmission consists of a period in which a communication unit transmits a signal to the master communication unit and a period in which the master communication unit transmits a message to all communication units. That is, the communication units separate signals from each other using the FDM method and separate signals between each communication unit and the master communication unit using the time-division multiplexing (TDM) method to avoid collisions. When communication unit 201 wants to transmit a message to communication unit 202, it first transmits the message from communication unit 201 to master communication unit 1, and then the master communication unit 1 transmits the message to communication unit 202 in the next message transmission period.To further explain, the master communication unit 1 is used to correct the time delay or attenuation values ​​of the communication units 201 to 20N to synchronize the time of all the communication units 201 to 20N. The master communication unit 1 also assigns the transmission frequency bands to be used by the communication units 201 to 20N. The master communication unit 1 adjusts the transmission energy of the communication units 201 to 20N corresponding to the transmission frequency bands B1 to BN so that the transmission energy of these communication units 201 to 20N is corrected by the time it reaches the master communication unit 1. Alternatively, self-compensation on the receiving side of the system can smoothly demodulate messages from all the communication units 201 to 20N. When the master communication unit 1 transmits a signal, all the communication units 201 to 20N are in receive mode. At this time, the communication units 201 to 20N do not transmit signals. Therefore, the master communication unit 1 can transmit signals in the entire frequency band, and all the communication units 201 to 20N can demodulate all messages transmitted from the master communication unit 1. This is advantageous for sharing messages across the entire vehicle, enabling early response.

[0017] In one embodiment, the master communication unit 1 allocates the communication units 201 to 20N so that the communication units 201 to 20N have uplink times corresponding to the transmission frequency bands B1 to BN for transmitting packets.

[0018] After the master communication unit 1 allocates uplink time to the communication units 201 to 20N corresponding to the transmission frequency bands B1 to BN, the communication units 201 to 20N simultaneously transmit packets to the master communication unit 1, and the master communication unit 1 allocates downlink time, and the master communication unit 1 transmits packets to the communication units 201 to 20N within the downlink time. That is, after the master communication unit allocates uplink time to these communication units corresponding to the transmission frequency bands, the communication units 201 to 20N simultaneously transmit their respective packets to the master communication unit 1 within the uplink time, and the master communication unit 1 demodulates the packets transmitted by all the communication units 201 to 20N and combines them into a complete OFDM signal. The master communication unit 1 transmits packets to the communication units 201 to 20N within the downlink time. Furthermore, when the master communication unit 1 transmits the packets, the communication units 201 to 20N enter a receiving state, and when the communication units 201 to 20N transmit packets, the master communication unit 1 enters a receiving state.

[0019] Furthermore, after the initial startup of the wired communication system 100, the master communication unit 1 adjusts the time delay and attenuation compensation of each communication unit so that all signals within the transmission frequency bands B1 to BN arrive at the master communication unit at the same time and with approximately the same unit energy. See FIG. 2. This figure shows a schematic diagram of the wired communication system 100 of the present invention at the initial startup stage. At this time, the communication units 201 to 20N have different frequency bands, different transmission powers, and different locations, resulting in different attenuation. Therefore, the master communication unit 1 causes each communication unit 201 to 20N to perform pre-energy compensation so that the energy across the entire communication frequency band is consistent when the receiving side of the system receives the signal. See FIG. 3. Assuming there are 16 communication units 201 to 20N on the same power line that can communicate with each other, and each communication unit is assigned a dedicated frequency band of four subcarriers for transmitting signals, FIG. 3 shows that the energy across the entire communication frequency band is consistent. In one embodiment, the attenuation correction can also be self-compensated by the receiving side of the master communication unit 1 .

[0020] In practical applications, the above concept can be extended to other complex or mixed modes, for example, to more effectively utilize the communication channel. For some application modules that are less sensitive to time delays (such as dimming lights or controlling window movements), multiple communication units can use the same frequency band, but they must use it in a time-division manner. This allows larger bandwidth to be reserved for communication units with large amounts of data or high real-time requirements. To operate certain high- and low-speed applications at lower cost, the wired communication system 100 may be in a second time domain. In this case, in addition to the master communication unit, other communication units may also use full-band communication (or the entire transmission frequency band). For example, each camera's image transmission allocates time in a TDM manner to send data back to the master communication unit. The OFDM modulation and demodulation capabilities of low-bandwidth communication units, such as light control and window control, can be reduced, which reduces the accuracy and efficiency of their OFDM signal processing, thereby reducing the overall system cost. In one embodiment, the number of OFDM subcarriers modulated and demodulated by the master communication unit is 256, and each subcarrier supports 1024 quadrature amplitude modulation (QAM). That is, 1024 different discrete states can be transmitted in each signal period. The system is connected to four high-speed communication units for the entire frequency band and 128 low-speed communication units. Each low-speed communication unit can modulate and demodulate only 16 consecutive subcarriers, and each subcarrier can demodulate only 64QAM. The master communication unit can set the first packet time transmitted by the master communication unit and the second to fifth packet times transmitted by the four high-speed communication units in sequence (256 subcarriers can be generated, and each subcarrier can demodulate 1024QAM).The sixth packet time is assigned to 16 low-speed communication units, each assigned to 16 consecutive non-overlapping subcarriers. Similarly, the seventh through thirteenth packet times are assigned to 16 non-overlapping low-speed communication units. Thus, the 128 low-speed communication units are assigned to transmit one message per eight packet times. The master communication unit then transmits a message, and so on. In other words, in each signal cycle, the packet times used by the master communication unit and the high-speed communication units are interspersed with the packet times used by the low-speed communication units, and each communication unit has its own dedicated and fixed transmission frequency band and message volume. In such a system, the low-speed communication units only have a subcarrier modulation capability of 64QAM, which reduces the requirements for the signal-to-noise ratio (SNR) of the transmitted signal, thereby increasing reliability. However, since its demodulation capability is limited to 16 subcarriers, when the master communication unit sends a message to the low-speed communication unit, the message must be placed within the set subcarriers and the 8 most significant bits (MSB). There are no restrictions on the messages that the master communication unit can send to the high-speed communication unit.

[0021] When the present invention is applied to in-vehicle communications, the communication quality can be improved by using a superior dedicated wire, such as a twisted pair or coaxial cable, for the communication wire. However, if a power line connected to the battery and supplying power to each in-vehicle application module 41N is used to reduce costs, each communication unit 201-20N must be provided with a low-pass filter 401 and a coupler 402 that bypasses the low-pass filter 401 and transmits signals to the power line mains to ensure communication quality. See FIG. 4A. FIG. 4A shows a schematic diagram of an embodiment of a wired communication system 400A that replaces the in-vehicle CAN / LIN bus of the present invention. A low-pass filter F must be connected in series between the battery BA and the power line. The main purpose of this is to prevent significant attenuation of signals in the communication frequency band due to the low impedance of the battery BA and the power consumption units, and to prevent noise generated by the power consumption units from entering the power line mains. The wired communication system 400A is a communication system using power lines.

[0022] Furthermore, because the vehicle's ground wire is generally replaced by the vehicle shell, DC power is usually supplied to each application module from the power line (live wire). The DC power then flows back to the battery from the vehicle shell's ground wire. If the network signal also passes through the same circuit, the signal is more likely to be radiated and external interference noise is more likely to be absorbed by the transmission line. Therefore, it is more appropriate to use a wire such as a twisted pair for differential signal transmission. That is, the DC current circuit follows the original vehicle shell circuit, but the network signal is returned via the twisted pair circuit. In this case, the differential signal transmission wire can be used as the same pair of DC power lines or two pairs of power lines (e.g., one 3.3V and the other 24V), which can moderately reduce the demand for power supply chips in each application module.

[0023] In power line embodiments of the present invention, the coupler typically uses a resistor in series with a capacitor or transformer to isolate the voltage on the power line and allow full channel messages to be transmitted and received (as shown in FIG. 5).

[0024] As described above, the wired communication system (power line) 400A includes application modules 411-41N, each of which includes a power consumption unit 301-30N and a corresponding communication unit 201-20N. That is, the vehicle's master communication unit 1 transmits electrical energy waves and network signals via the vehicle power line. A low-pass filter 401 is disposed at the entrance of the power consumption end E of each application module 411-41N or some of the application modules 411-41N of the device 400A to filter out the network signals, allowing the electrical energy waves to enter the power consumption units 301-30N of the application modules 411-41N. A coupler 402 is used to generate a coupling path P1, which allows the network signals to pass through the coupling path P1 without passing through the low-pass filter 401 and enter the transmitting end T via the first coupler 402. That is, the network enters the communication units 201 to 20N in the application modules 411 to 41N via the coupling path P1 generated by the coupler 402. The power consumption units 301 to 30N are power supply units for the corresponding communication units.

[0025] Low-pass filter 401 is placed at the entrance of each power consumption end E or some of the power consumption ends E of wired communication system 400A, and low-pass filter 401 separates the power line into power consumption end E and transmission end T, so that the power line impedance on the transmission end T side is not affected by the power consumption end E side.

[0026] Please refer to FIG. 4B. FIG. 4B shows a schematic diagram of an embodiment of a wired communication system 400B replacing an in-vehicle CAN / LIN bus according to the present invention. The difference between the wired communication system 400B replacing an in-vehicle CAN / LIN bus and the system 400A is that in this embodiment, an active isolator 403 is used instead of a low-pass filter, thereby reducing the requirement for a transformer or inductor value. In other words, the active isolator 403 is installed at the entrance of each power consumption end E or some of the power consumption ends E of the wired communication system, and the active isolator 403 separates the power line into the power consumption end E and the transmission end T, and removes the network signal, preventing the electric energy wave from entering the power consumption end E. The other principles are the same as those described above.

[0027] Please refer to FIG. 4C. FIG. 4C shows a schematic diagram of one embodiment of an active isolator 403. This isolator includes two transformers K1 and K2 connected in series to a power line, and two amplifiers A1 and A2 connected to the start of the primary coil and the start of the secondary coil of the transformer K1, respectively. The output terminal of amplifier A1 is connected to the inverting input terminal of amplifier A1, and the output terminal of amplifier A2 is connected to the inverting input terminal of amplifier A2, and the output terminals of amplifiers A1 and A2 are connected between the two transformers K1 and K2. The non-inverting input terminals of amplifiers A1 and A2 are connected to the start of the primary coil and the start of the secondary coil of transformer K1, respectively. A high-voltage capacitor C is connected in parallel to the high-voltage power line. That is, the high-voltage capacitor C is connected in parallel between the end of the primary coil of transformer K2, the end of the secondary coil, and the power line. A capacitor C is connected in parallel between the start end of the primary coil and the start end of the secondary coil of the transformer K1, the non-inverting input terminals of the amplifiers A1 and A2, and the power line, and between the end end of the primary coil and the end of the secondary coil of the transformer K1, the inverting input terminals and output terminals of the amplifiers A1 and A2, and the power line.

[0028] Furthermore, whether a power line or a superior independent transmission line is used as the in-vehicle transmission line, a specific architecture is required to match the transceiver impedance, and the transceiver circuits of the communication units 201 to 20N shown in FIG. 5 are one example. In this embodiment, the communication units 201 to 20N each include two capacitors C and two matching resistors Rs connected in series with the capacitors C, respectively, for impedance matching. A line driver LD (line driver) is provided between the transmitting side Tx of the communication unit and the matching resistor Rs, and a low-noise amplifier LNA is provided between the receiving side Rx of the communication unit, the capacitor C, and the matching resistor Rs. The matching resistors RS are each connected in series with the capacitor C for impedance matching, and a switch S is connected in parallel to the transmitting side Tx. When the transmitting side Tx transmits a signal, the switch S is open, and when the transmitting side Tx does not transmit a signal, the switch S is short-circuited. When N communication units are connected to a power line, the low-frequency impedance of the transmission line is much smaller than the matching resistance, and the wavelength of the transmission frequency band is much longer than the length of the transmission line, the signal output from the line driver LD of each communication unit will be attenuated to 1 / (N+1) of its original level after reaching the transmission line.If 99 communication units are installed on the power line, the signal received by the receiving side Rx will be 1 / 100 of the superposition of the signals output from all the communication units, that is, it will be attenuated by 40dB.

[0029] Furthermore, because the vehicle's ground wire is generally replaced by the vehicle shell, DC power is usually supplied to each application module from the power line (live wire). The DC power then flows back to the battery from the vehicle shell's ground wire. If the network signal also passes through the same circuit, the signal is more likely to be radiated and external interference noise is more likely to be absorbed by the transmission line. Therefore, it is more appropriate to use a wire such as a twisted pair for differential signal transmission. That is, the DC current circuit follows the original vehicle shell circuit, but the network signal is returned via the twisted pair circuit. In this case, the differential signal transmission wire can be used as the same pair of DC power lines or two pairs of power lines (e.g., one 3.3V and the other 24V), which can moderately reduce the demand for power supply chips in each application module.

[0030] If some communication units have low real-time and speed requirements, multiple communication units can be connected to the same power line and use the same frequency band, which requires more complex anti-collision mechanisms, such as restricting different communication units using the same frequency band to only transmit signals at specific times.

[0031] In the case of groups within the same large frequency band, the communication units can communicate with each other directly via a specific protocol, but in the case of groups with different large frequency bands, the communication units must communicate with each other via units equipped with transceivers for different frequency bands, for example, relaying communication via a master communication unit in a vehicle or other regional adapter board (Figure 6). Figure 6 shows a method similar to Figure 4A, which is applicable to the aforementioned "one-to-many" or "many-to-many" communication modes, in which the wired communication system is connected to the master communication unit via different bandpass filters corresponding to different transmission frequency bands, and the bandpass filters can filter signals of different frequency bands to the communication units within the communication unit group. The wired communication system includes multiple transmitters corresponding to different transmission frequency bands B1 to BN. communication It has a set of modules and communicationCommunication units that do not belong to the same module group cannot communicate directly with each other and have different transmission frequency bands. In one embodiment, a low-frequency band (e.g., 100 KHz to 2 MHz) is used as a large frequency band (combined frequency band). The communication units 201 to 203 using this frequency band each have their own dedicated transmission frequency band, allowing them to transmit signals directly to each other and demodulate them in real time without going through the master communication unit. Signals from all communication units 201 to 203 using this large frequency band are coupled to the transmission line via a 100 KHz to 2 MHz bandpass filter. The other large frequency band (combined frequency band) is 10 MHz to 100 MHz, and communication units 204 to 20N using this large frequency band must communicate with each other via the master communication unit. The inlet coupler is a 10 MHz to 100 MHz bandpass filter or a 10 MHz highpass filter. To avoid mutual interference, a guard band must be secured between the two large frequency bands, and the master communication unit is equipped with a transceiver (not shown) capable of transmitting and receiving multiple OFDM signals.

[0032] See Figure 7. For some special applications, such as in-vehicle communications, low-pass filters can be installed between different sections of the power line to increase bandwidth, and additional master communication units can be connected. Communications on different sections of the power line must be transmitted through this master communication unit. The simplest method is to divide the master communication unit into four lines: left, right, top, and bottom. The principle is the same as in Figure 4A, except that it is connected to the power supply Vs via a low-pass filter and has four sets of communication units 20N_1 to 20N_4 connected to each section of the power line. [Explanation of symbols]

[0033] 100: Wired communication systems (non-power line) 400A: Wired communication systems (power lines) 400B: Wired communication system (power line) 401, F: Filter 402: Coupler 403: Active isolator P1: Binding pathway 201~20N, 20N_1~20N_4: Communication units 101~10N, 411~41N: Application modules 301~30N: Power consumption unit 1: Master communication unit RS: matching resistance C: Capacitor LNA: amplifier LD: Line driver K1~K2: Transformer A1~A2: Amplifier S: Switch TX: Transmitter RX: Receiver Vs: Power supply BA: Battery E: Power consumption end T: Transmitting end

Claims

1. A wired communication system that replaces an in-vehicle CAN / LIN bus, the wired communication system has a power line or a transmission line connected to a plurality of communication units; The wired communication system includes a master communication unit that performs clock correction of the plurality of communication units to complete synchronization or correct time delay or attenuation values; In a first time domain, each of the plurality of communication units has a transmission frequency band, the transmission frequency bands of the plurality of communication units do not overlap with each other and do not overlap with the transmission frequency band of the master communication unit, all the transmission frequency bands can be combined into a complete OFDM frequency band, and there is no guard band between the plurality of transmission frequency bands; Wired communication system.

2. The master communication unit performs time synchronization with the plurality of communication units, so that packets simultaneously transmitted from the plurality of communication units and the master communication unit are combined into a complete OFDM signal, which can be simultaneously received and demodulated by the plurality of communication units and the master communication unit; The master communication unit must maintain continuous clock synchronization of all of the plurality of communication units, and the master communication unit and the plurality of communication units simultaneously transmit packets of the same length, thereby maintaining all signals demodulatable by each of the plurality of communication units and the master communication unit. The wired communication system of claim 1 .

3. the master communication unit assigns the plurality of communication units such that the plurality of communication units have corresponding transmission frequency bands; the master communication unit can use the transmission frequency band used by all of the plurality of communication units within a downlink time; the master communication unit assigning uplink time to the plurality of communication units for transmitting packets and assigning the downlink time to transmit packets to the plurality of communication units; The master communication unit adjusts the transmitting sides of all of the plurality of communication units in the wired communication system to perform time delay correction, so that when packets transmitted from each of the plurality of communication units reach the master communication unit, all packets can be combined into a complete OFDM signal. The wired communication system of claim 1 .

4. the master communication unit allocates the uplink time of the plurality of communication units corresponding to the transmission frequency band, and then the plurality of communication units simultaneously transmit their respective packets to the master communication unit during the uplink time; and the master communication unit demodulates and combines all packets transmitted from the plurality of communication units into the complete OFDM signal; the master communication unit transmits packets to the plurality of communication units during the downlink time; 4. The wired communication system according to claim 3.

5. 5. The wired communication system of claim 4, wherein when the master communication unit transmits a packet, the plurality of communication units are in a receiving state, and when the plurality of communication units transmit a packet, the master communication unit is in a receiving state.

6. the master communication unit includes a transceiver capable of transmitting and receiving a plurality of OFDM signals, and communication modules in the wired communication system are connected to the master communication unit via bandpass filters corresponding to the plurality of different transmission frequency bands; The plurality of communication units that do not belong to the same communication module group cannot communicate directly with each other, but can simultaneously communicate with the master communication unit. The wired communication system of claim 1 .

7. Each of the plurality of communication units Two capacitors, two matching resistors connected in series to the two capacitors, respectively, for impedance matching; Including, a line driver is provided between the transmitting side of the communication unit and the two matching resistors; a low noise amplifier (LNA) is provided, the input terminal of the low noise amplifier is connected to a node between the two capacitors and the two matching resistors, and the output terminal of the low noise amplifier is connected to a receiving side of the communication unit; 3. The wired communication system of claim 2.

8. Each of the plurality of communication units Two capacitors, two matching resistors connected in series to the two capacitors, respectively, for impedance matching; Including, a line driver is provided between the transmitting side of the communication unit and the two matching resistors; a low noise amplifier (LNA) is provided, the input terminal of the low noise amplifier is connected to a node between the two capacitors and the two matching resistors, and the output terminal of the low noise amplifier is connected to a receiving side of the communication unit; 6. The wired communication system according to claim 5.

9. The wired communication system transmits electrical energy waves and network signals over the power lines; the wired communication system includes a first low-pass filter and a first coupler; The first low-pass filter is installed at the entrance of each power consumption end or some power consumption ends of the wired communication system, and the first low-pass filter separates the power line into the power consumption end and the transmission end, and removes the network signal, so that the electric energy wave enters the power consumption end; the first coupler is used to generate a first coupling path, and the first coupling path allows the network signal to pass through the first low-pass filter, not through the first low-pass filter, and enter the transmitting end via the first coupler through the first coupling path; The power line impedance of the transmitting end is not affected by the power consuming end; 3. The wired communication system of claim 2.

10. The wired communication system transmits electrical energy waves and network signals over the power lines; the wired communication system includes a first low-pass filter and a first coupler; The first low-pass filter is installed at the entrance of each power consumption end or some power consumption ends of the wired communication system, and the first low-pass filter separates the power line into the power consumption end and the transmission end, and removes the network signal, so that the electric energy wave enters the power consumption end; the first coupler is used to generate a first coupling path, and the first coupling path allows the network signal to pass through the first low-pass filter, not through the first low-pass filter, and enter the transmitting end via the first coupler through the first coupling path; The power line impedance of the transmitting end is not affected by the power consuming end; 6. The wired communication system according to claim 5.

11. 4. The wired communication system of claim 3, wherein the master communication unit adjusts the transmission energies of the plurality of communication units so that all signal energies within the plurality of transmission frequency bands are the same.

12. A wired communication system as described in claim 1, wherein in a second time domain, the multiple communication units use the same transmission frequency band, but the multiple communication units must use the same transmission frequency band in a time-division manner.

13. A wired communication system as described in claim 1, wherein in a second time domain, the multiple communication units on the power line use the same transmission frequency band, but different multiple communication units using the same transmission frequency band can only transmit signals at specific times.

14. 2. The wired communication system of claim 1, wherein in a second time domain, in addition to the master communication unit, at least one of the plurality of communication units on the same power line uses all of the transmission frequency bands.

15. 15. The wired communication system according to claim 14, wherein a plurality of high-speed communication units and a plurality of low-speed communication units are connected to the wired communication system.

16. 16. The wired communication system of claim 15, wherein in each signal period, packet times used in turn by said master communication unit and said plurality of high-speed communication units are interspersed with packet times of said plurality of low-speed communication units.

17. 17. The wired communication system of claim 16, wherein each low-speed communication unit is designated to use contiguous, non-overlapping subcarriers.

18. The wired communication system transmits electrical energy waves and network signals over the power lines; the wired communication system includes an active isolator and a first coupler; The active isolator is installed at the entrance of each power consumption end or some power consumption ends of the wired communication system, and the active isolator separates the power line into the power consumption end and the transmission end, and removes the network signal so that the electrical energy wave enters the power consumption end; the first coupler is used to generate a first coupling path, and the first coupling path allows the network signal to pass through the first coupling path without passing through the active isolator and enter the transmitting end via the first coupler; The power line impedance of the transmitting end is not affected by the power consuming end; 3. The wired communication system of claim 2.

19. The active isolator comprises: two transformers each connected in series to the power line; two amplifiers connected to the start of the primary coil and the start of the secondary coil of a first transformer of the two transformers, respectively; a plurality of capacitors connected in parallel between the start of the primary coil and the start of the secondary coil of the first transformer, the non-inverting input terminals of the two amplifiers and the power line, and between the end of the primary coil and the end of the secondary coil of the first transformer, the inverting input terminals of the two amplifiers, the output terminals and the power line; Including, The output terminals of the two amplifiers are respectively connected to the inverting input terminals of the two amplifiers and between the two transformers, and the non-inverting input terminals of the two amplifiers are respectively connected to the start of the primary coil and the start of the secondary coil of the first transformer; Another capacitor is connected in parallel to the power line on the high voltage side.

20. The wired communication system of claim 18.

20. The wired communication system transmits electrical energy waves and network signals over the power lines; the wired communication system includes an active isolator and a first coupler; The active isolator is installed at the entrance of each power consumption end or some power consumption ends of the wired communication system, and the active isolator separates the power line into the power consumption end and the transmission end, and removes the network signal so that the electrical energy wave enters the power consumption end; the first coupler is used to generate a first coupling path, and the first coupling path allows the network signal to pass through the first coupling path without passing through the active isolator and enter the transmitting end via the first coupler; The power line impedance of the transmitting end is not affected by the power consuming end; 6. The wired communication system according to claim 5.

21. The active isolator comprises: two transformers each connected in series to the power line; two amplifiers connected to the start of the primary coil and the start of the secondary coil of a first transformer of the two transformers, respectively; a plurality of capacitors connected in parallel between the start of the primary coil and the start of the secondary coil of the first transformer, the non-inverting input terminals of the two amplifiers and the power line, and between the end of the primary coil and the end of the secondary coil of the first transformer, the inverting input terminals of the two amplifiers, the output terminals and the power line; Including, The output terminals of the two amplifiers are respectively connected to the inverting input terminals of the two amplifiers and between the two transformers, and the non-inverting input terminals of the two amplifiers are respectively connected to the start of the primary coil and the start of the secondary coil of the first transformer; Another capacitor is connected in parallel to the power line on the high voltage side.

21. The wired communication system of claim 20.

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