A low-latency synchronous forwarding system based on MCU

Abstract

The present invention discloses a low-latency synchronous forwarding system based on an MCU, which is applied to the communication field. Aiming at the existing forwarding system based on an MCU, the mode of receiving first and then forwarding increases the system latency. At the same time, the existing system does not consider the problem of forwarding signal synchronization, and there is a problem that the forwarding signal cannot meet the protocol requirements of the system due to the low rate of the transmitting device. In the present invention, the transmitting signal is synchronized based on the output clock of the transmitting device in the MCU, eliminating the problem of asynchronization between the system forwarding signal and the base station or the transmitting device, and avoiding the problem that the forwarding signal cannot meet the protocol requirements of the system due to the low rate of the transmitting device.

Description

Technical Field

[0001] The present invention belongs to the field of signal processing and system control, and particularly relates to a forwarding system based on an MCU. Background Art

[0002] As is well known, in order to reduce system cost, power consumption, and design complexity, the vast majority of systems use an MCU (microprogrammed control unit) to implement signal processing and system control functions. However, the system based on an MCU has a low rate and cannot implement signal synchronization functions, which limits its application scenarios. For systems that need to meet the specified protocol timing, especially high-speed / parallel systems, most use an FPGA (field programmable gata array) to implement. However, the FPGA has high power consumption, high cost, and high design complexity, and it is difficult to be used in fields such as low power consumption, low cost, and passive. These fields mostly use an MCU to implement, and it is very difficult for their system timing. At the same time, in application scenarios where a repeater is needed to improve the system coverage, additional latency is introduced, which causes the system to malfunction or requires more expensive components and complex design methods to meet the system timing requirements, which further increases the system cost, power consumption, and design complexity. Therefore, there is an urgent need for a low-power and low-cost method to solve the latency and synchronization problems in the repeater.

[0003] The existing design method of the forwarding system based on an MCU is that the repeater first receives the data transmitted by the base station, then re-encodes the data according to the protocol standard required by the system, and finally forwards it through the transmitting circuit.

[0004] The disadvantages of the existing technology are: the existing receive-then-forward mode increases the system latency, and at the same time, the existing system does not consider the problem of forwarding signal synchronization, and there is a problem that the forwarding signal cannot meet the protocol requirements of the system due to the low rate of the transmitting device. Summary of the Invention

[0005] To solve the above technical problems, the present invention proposes a low-latency synchronous forwarding system based on an MCU, which directly forwards signals without receiving data, reduces the system latency, and synchronizes the transmitted signals based on the output clock of the transmitting device in the MCU, eliminating the problem of asynchronous forwarding signals between the system and the base station or the transmitting device, and avoiding the problem that the forwarding signal cannot meet the protocol requirements of the system due to the low rate of the transmitting device.

[0006] The technical solution adopted by the present invention is: a low-latency synchronous forwarding system based on an MCU, including: a receiving antenna, a transmitting antenna, a receiving link, a transmitting link, a power supply module, and an MCU; the power supply module supplies power to the receiving link, the transmitting link, and the MCU;

[0007] The receiving link demodulates the RF signal received by the receiving antenna, and the demodulated signal is input to the MCU; the MCU performs low-latency synchronous forwarding on the demodulated signal. After the forwarded signal is modulated by the transmitting link, it is transmitted by the transmitting antenna.

[0008] It further includes: a system control module, a low-latency forwarding module, and a synchronous forwarding module implemented based on the MCU; the system control module is respectively connected to the receiving link and the transmitting link through SPI. The system control module is used to generate true random numbers; the MCU selects either the low-latency forwarding module or the synchronous forwarding module to work; under the control of the system control module, the low-latency forwarding module and the synchronous forwarding module output a modulated signal based on the demodulated signal.

[0009] The low-latency forwarding module is set to trigger on both edges of the demodulated signal. When the MCU detects that the demodulated signal is a falling edge, it sets the forwarded signal to low; when the MCU detects that the demodulated signal is a rising edge, it sets the forwarded signal to high.

[0010] The synchronous forwarding module is set to trigger on the falling edge of the demodulated signal and the falling edge of the output clock signal of the transmitting device; after the MCU detects that the demodulated signal is a falling edge, and then continues to detect the falling edge of the clock signal, it sets the forwarded signal to low; then continues to detect the falling edge of the clock signal and sets the forwarded signal to high.

[0011] The transmitting link encodes the input modulated signal and transmits it through the transmitting antenna.

[0012] Advantages of the present invention: The present invention proposes a low-latency synchronous forwarding system based on the MCU, which can implement the RF signal forwarding function. At the same time, the MCU is used to achieve low-latency forwarding of signals and can also achieve synchronous forwarding of signals. It can achieve parallel transceiver functions similar to FPGAs. At the same time, it does not affect the networking function with the base station, greatly reducing the cost, power consumption, and design complexity of the forwarding system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is the architecture of the low-latency synchronous forwarding system based on the MCU;

[0014] Figure 2 is the working process of the low-latency forwarding module;

[0015] Figure 3 is the working timing of the low-latency forwarding module;

[0016] Figure 4 is the working process of the synchronous forwarding module;

[0017] Figure 5 is the working timing of the synchronous forwarding module. DETAILED DESCRIPTION OF THE INVENTION

[0018] To facilitate the understanding of the technical content of the present invention by those skilled in the art, the following further explains the content of the present invention in conjunction with the accompanying drawings.

[0019] The low-latency synchronous forwarding system architecture based on MCU proposed by the present invention is as Figure 1 shown, including a transceiver antenna, a receiving link, a transmitting link, a power supply module, an MCU, etc. Among them, the MCU realizes a system control module, a low-latency forwarding module, a synchronous forwarding module, etc., and can also realize the networking function with a base station (control center). In the figure, f1 and f2 respectively represent the receiving and transmitting frequencies, and BPF1 and BPF2 are filters for the corresponding frequencies.

[0020] The system control module controls the ADC sampling time, realizes signal processing, generates the final true random number, and realizes data reception and transmission, etc.

[0021] The MCU controls the working states of the receiving device of the receiving link and the transmitting device of the transmitting link through the SPI bus. The receiving device demodulates the received radio frequency signal and outputs a digital signal, that is, a demodulated signal. The MCU selects the low-latency forwarding module or the synchronous forwarding module to work; the low-latency forwarding module judges the received signal state and outputs a modulation signal, and the synchronous forwarding module outputs a modulation signal, that is, a forwarding signal, under the control of the output clock signal of the transmitting device.

[0022] A) Low-latency forwarding module

[0023] The working process of the low-latency forwarding module is as Figure 2 shown. The MCU sets the demodulated signal pin to double-edge triggering (both rising edge and falling edge trigger). When the MCU detects that the demodulated signal is a falling edge, it sets the forwarding signal to low; when it detects that the demodulated signal is a rising edge, it sets the forwarding signal to high; if it detects the start of networking, the low-latency forwarding module continues to execute, and if it detects the end of networking, the low-latency forwarding module ends its work.

[0024] The working timing of the low-latency forwarding module is as Figure 3 shown, where the transmitted signal is the modulation signal output by forwarding, RT cal is the judgment symbol for the encoded data being 0 or 1, data0 and data1 are the symbols for the encoded data 0 and 1 respectively, the symbol length of RT cal is longer than the symbol length of data1, and the symbol length of data1 is longer than the symbol length of data0. As can be seen from Figure 3 , the maximum latency of the low-latency forwarding module is only 1 clock cycle of the output of the transmitting device, but the lengths of the forwarded symbols are different, which is likely to cause subsequent decoding errors. Especially, the high-level duty cycle of data0 is too small, about 30% or so, which is likely to cause the passive tag (RFID application scenario) to lose power, thus making the tag unable to work properly.

[0025] In the ultra-high frequency RFID application scenario, the decoding of data0 and data1 is determined by the following formula:

[0026]

[0027] Among them, RT cal is used to represent the length of the data symbols of data0 and data1. Formula (1) can be understood as: when the length of the data symbol in the signal forwarded by the transponder received by the tag is greater than RT cal / 2, it means that the symbol is data1; when the length of the data symbol in the forwarded signal received by the tag is less than RT cal / 2, it means that the symbol is data0 (data0).

[0028] Therefore, from Figure 3 the timing of, it can be seen that to meet the timing requirements of the ultra-high frequency RFID system, RT cal in the forwarded output signal should meet the following inequality requirements:

[0029]

[0030] Among them, T clk is the output clock period of the transmitting device. After simplification, it can be obtained:

[0031] 2data0 + 3T clk < RT cal < 2data1 - 3T clk (3)

[0032] When RT cal meets formula (3), the forwarded signal will not cause decoding errors in the passive tag, and at the same time, a 1-clock cycle delay function is realized. It is equivalent to using an FPGA or a dedicated chip, reducing the system delay of the traditional MCU forwarding method, and having lower power consumption and cost.

[0033] B) Synchronous forwarding module

[0034] The working process of the synchronous forwarding module is as Figure 4 shown. The MCU sets the falling edge trigger of the demodulation signal and the falling edge trigger of the clock signal. After the MCU detects that the demodulation signal is at the falling edge, and then continues to detect the falling edge of the clock signal, it sets the forwarded signal to low; then continues to detect the falling edge of the clock signal and sets the forwarded signal to high; if it detects the start of networking, the synchronous forwarding module continues to execute, and if it detects the end of networking, the synchronous forwarding module ends its work.

[0035] The working timing of the synchronous forwarding module is as Figure 5 shown, starting from Figure 5It can be seen that the maximum time delay of the synchronous forwarding module is 2 clock cycles (for example, when it just changes at the rising edge of the clock, it will be delayed by 2 clock cycles). However, the low level of the forwarded symbol is fixed at one clock cycle, and the duty cycle of the high level of data0 is not less than 50% and not greater than 75%, which is relatively moderate and will not cause power failure of the passive tag (RFID application scenario), thus improving the system reliability.

[0036] Therefore, from Figure 5 the timing of, to meet the timing requirements of the ultra-high frequency RFID system, RT in the forwarded output signal cal should meet the following inequality requirements:

[0037]

[0038] where, T clk is the output clock cycle of the transmitting device. After simplification, we can get:

[0039] 2data0 + 6T clk < RT cal < 2data1 - 6T clk (5)

[0040] When RT cal meets formula (5), the forwarded signal will not cause decoding errors of the passive tag, and at the same time, it realizes a time delay of 2 clock cycles and a synchronization function. Its sum is comparable to that of using an FPGA or a dedicated chip, and the power consumption and cost are lower. Further, it reduces the system time delay of the traditional MCU forwarding method and realizes the synchronization function that the traditional MCU forwarding method cannot achieve.

[0041] In practical applications, according to the specific application scenario, select a low-delay forwarding module or a synchronous forwarding module to work; for example, in an application scenario where fast forwarding is required and the data rate is relatively low, synchronous forwarding is not needed. The host computer sends a low-delay selection command, and the MCU uses the low-delay forwarding function; if a scenario requires a high data rate, if low-delay forwarding is used, the forwarding may be inaccurate, so synchronous forwarding is needed. The host computer sends a synchronous forwarding command, and when the MCU receives this command, it uses the synchronous forwarding function.

[0042] In this field, it is generally considered that if the data rate is greater than or equal to 80 kbps, it belongs to a relatively high data rate; otherwise, the data rate is relatively low.

[0043] Those of ordinary skill in the art will realize that the embodiments described herein are to assist the reader in understanding the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. For those skilled in the art, various modifications and variations can be made to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A low-latency synchronous forwarding system based on MCU, characterized in that Including: Receiving antenna, transmitting antenna, receiving link, transmitting link, power supply module, MCU; The power supply module supplies power to the receiving link, transmitting link and MCU; The receiving link demodulates the radio frequency signal received by the receiving antenna, and the demodulated signal is input to the MCU; The MCU performs low-latency synchronous forwarding on the demodulated signal. After the forwarded signal is modulated by the transmitting link, it is transmitted by the transmitting antenna; It also includes: a system control module, a low-latency forwarding module, and a synchronous forwarding module implemented based on the MCU; The system control module is respectively connected to the receiving link and the transmitting link through SPI. The system control module is used to generate true random numbers; the MCU selects the low-latency forwarding module or the synchronous forwarding module to work; the low-latency forwarding module and the synchronous forwarding module output modulated signals based on the demodulated signal under the control of the system control module; The low-latency forwarding module is set to trigger on both edges of the demodulated signal. When the MCU detects that the demodulated signal is a falling edge, the forwarded signal is set to low; when the MCU detects that the demodulated signal is a rising edge, the forwarded signal is set to high; The synchronous forwarding module is set to trigger on the falling edge of the demodulated signal and the falling edge of the output clock signal of the transmitting device; after the MCU detects that the demodulated signal is a falling edge, and then continues to detect the falling edge of the clock signal, the forwarded signal is set to low; then continue to detect the falling edge of the clock signal, and set the forwarded signal to high; The transmitting link encodes the input modulated signal and transmits it through the transmitting antenna.

2. The low-latency synchronous forwarding system based on MCU according to claim 1, characterized in that The receiving link includes a first band-pass filter, a low-noise amplifier, and a receiving device; the radio frequency signal input by the receiving antenna is filtered by the first band-pass filter, and the signal amplified by the low-noise amplifier enters the receiving device, and the receiving device performs demodulation processing on it and outputs a demodulated signal.

3. The low-latency synchronous forwarding system based on MCU according to claim 2, characterized in that The transmitting link includes a second band-pass filter, a power amplifier, and a transmitting device; the transmitting signal obtained by encoding the forwarded signal by the transmitting device is amplified by the power amplifier and then filtered by the second band-pass filter, and finally transmitted by the transmitting antenna.

4. A low-latency synchronous forwarding system based on an MCU according to claim 3, characterized in that, The modulated signal is provided with a judgment symbol. The symbol length of data 0 is less than the judgment symbol length, and the symbol length of data 1 is greater than the judgment symbol length.

5. A low-latency synchronous forwarding system based on MCU according to claim 4, characterized in that, The judgment symbol length in the modulated signal output by the low-latency forwarding module satisfies the following inequality requirements: Among them, T clk is the output clock period of the transmitting device, data1 represents the symbol length of data 1, and data0 represents the symbol length of data 0.

6. The low-latency synchronous forwarding system based on MCU according to claim 5, wherein, The judgment symbol length in the modulated signal output by the synchronous forwarding module satisfies the following inequality requirements:

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