WO2012119394A1

WO2012119394A1 - Wireless communication system and wakeup method thereof

Info

Publication number: WO2012119394A1
Application number: PCT/CN2011/078471
Authority: WO
Inventors: 雷兆军
Original assignee: 深圳市华奥通通信技术有限公司
Priority date: 2011-03-10
Filing date: 2011-08-16
Publication date: 2012-09-13
Also published as: CN102625423B; CN102625423A

Abstract

The present invention relates to a wireless communication system and a wakeup method thereof; the wakeup method comprises: a master device for converting pseudo random sequence code into a wakeup bit stream through coding when there is communication demands, modulating the wakeup bit stream into a wireless modulation signal, and sending the wireless modulation signal continuously to at least one slave device within a preset time duration, the preset time duration is longer than or equal to the sum of the dormant period and the detection period of the slave device; each slave device receiving the wireless modulation signal within the detection period, and demodulating the wireless modulation signal into the wakeup bit stream, then sampling and decoding the wakeup bit stream, and determining whether to wake up the slave device according to the decoding results. By implementing the technical solution of the present invention, the wireless communication devices involved in communication require no chronological synchronization; anti-interference ability is strong, solving the problem of identification and wrong wakeups, and enhances reliability; and the detection period of the slave device is shortened, decreasing the receiving a window time of the slave device, lowering the power consumption of the communication system.

Description

Wireless communication system and wake-up method thereof

The present invention relates to the field of communications technologies, and more particularly to a wireless communication system and a wake-up method thereof. Background technique

Micro-power (short-range) wireless communication technology began to appear at the end of the last century. After more than ten years of development, it has been widely used in industrial control, home intelligence, wireless remote control, security alarm, environmental monitoring, intelligent meter reading, toxic and harmful gas monitoring, Logistics, RFID and other fields. In recent years, the Internet of Things has become a new growth point for future economic development after the financial crisis. And short-range wireless communication technology will be more developed in the Internet of Things (especially sensor network:) applications.

The concept of the Internet of Things is almost accompanied by a low-carbon economy. As one of the main communication methods of the Internet of Things, short-range wireless digital communication technology must conform to the development trend of low-carbon and low-energy, and develop toward low-power and micro-power consumption. In addition, as mobile communication devices become more widely used, battery-powered products are becoming more and more demanding, and power consumption requirements are more demanding.

So how do you reduce the overall power consumption of wireless communication devices? Obviously, it is unrealistic to only reduce the transmitter's transmit power, or just reduce the receiver's current consumption. The effect of this method is not only inconspicuous, but also has the adverse consequences of reduced communication quality. Only when the communication device sleeps in idle state can the average power consumption of the communication device be greatly reduced, and the purpose of reducing consumption is achieved. At the same time, battery-powered devices can extend battery life by several or even thousands of times.

For a half-duplex wireless communication system or network of any structure, any protocol consisting of more than two wireless transceivers, one of the devices actually has little time to transmit or receive. When the communication device does not operate in transmission and does not operate in reception, it is put into a sleep state, which can greatly reduce the average power consumption. Because of the current consumption in the sleep state, only micro-ampere, or even a few microamps. The current when the wireless communication device transmits is several tens of milliamperes or more, and the receiving current is also between ten to several tens of milliamps. Therefore, in a communication system that introduces a sleep mechanism, the longer the sleep time, the lower the average power consumption. When a certain group or group of wireless communication devices are in a sleep state, they are not received or transmitted, and are in a non-working state, but communication is not successful when other communication devices need to communicate with them. In this way, a process or method is needed to enable the wireless communication device in a dormant state to sense and complete communication when other devices need to communicate with it, and wake up the wireless communication device that is in a dormant state. Currently, wireless communication will be performed. There are several ways to wake up the device from sleep state, as described below: 1. Timing wake-up communication method

The timed wake-up communication method is all wireless communication devices participating in the communication, and according to a certain timing cycle, or the timing of the next communication is agreed upon each communication, when the time is up, the plurality of devices participating in the communication simultaneously enter the working state from the sleep state. , the method of entering sleep after completing communication. The timing of the timing wake-up communication method is shown in Figure 1.

In Figure 1, T can be a constant or a variable. When T is a variable, every communication, all devices participating in the communication must agree on the time interval T of the next communication. t is the working time. At some point during this working time, if only one device is in the transmitting state, the other devices are in the receiving state. Obviously, the larger the ratio of T/t, the smaller the average power consumption.

The shortcomings of the timed wake-up communication method are:

1) All wireless communication devices participating in the communication must be synchronized in time, and the clock requirements are higher;

2) Initial synchronization takes a long time and complicated process;

3) The clocks of different wireless communication devices will drift due to errors, and a calibration mechanism is needed for calibration;

4) The longer the sleep time, the greater the clock drift. Once the drift is too large or the device is disconnected from synchronization, the resynchronization takes a lot of cost, because the device that is out of sync is out of the system;

5) Communication real-time and flexibility is not strong. If a device has sudden communication needs and other devices are still sleeping, communication cannot be completed in a short time, and only waiting for the time to arrive.

Second, the signal strength wake-up method

The signal strength wake-up method is to use the signal strength RSSI received by the receiver at a certain time, and determine whether the system generates communication demand within a certain period of time through the set threshold. If yes, the device The method of entering the working state from the sleep state, this method is also called the analog wake-up method. Its timing diagram is shown in

2 is shown.

In a system that uses the signal strength wake-up method, the device has a master-slave relationship, the device that initiates the communication is the master device (only one:), and the other devices are slave devices (one or more:). In most applications, the master and slave devices are fixed. However, in some more complex systems, the definition of master and slave devices can be dynamic. A device may be a master device or a slave device at a certain moment.

The main device workflow of the signal strength wake-up method is as follows: When there is communication demand, the master device first sends a wake-up signal with a duration of T _s , which may be a carrier wave or a modulated signal. T _s ^ T + t. After the master device sends the wake-up signal, it assumes that the other slave devices are woken up, immediately enters the normal communication, and exchanges data with the slave device for a duration of T _e . After the data exchange is completed, the slave device goes to sleep. For a slave device that fails communication, the master device needs to initiate an error handling mechanism for processing.

The slave device wake-up method has the following workflow: According to the fixed period Τ+t, it alternates to sleep-received-received-received-received state. During time T, the slave device is dormant. During time t, the slave is in the receive state but does not receive data and only measures the value of RSSI. t is the window of the signal strength wake-up method. Since the different slave devices are not synchronized, the phase of the window is different.

If the RSSI measurement is below the preset threshold, it means that there is no communication request and the slave goes to sleep. If the RSSI measurement value is higher than or equal to the preset threshold value, it indicates that the master device sends a communication request, and the slave device does not enter the sleep state temporarily, and continues to be in the receiving state, and the waiting time is T _w . The value of 1^ of different slave devices is different. During 1^, the slave device is still in the receiving state, but cannot communicate normally, and the energy during this period is wasted.

After the waiting period of T _w , the slave device receives the command or data of the master device and completes the established transceiver process T _a , and then enters the sleep state. If the command or data sent by the master device is not received due to interference or the like, it indicates that the communication fails, and the slave device is waiting for time T. _{After ut} , it goes to sleep again (slave 3 in Figure 2).

The advantage of the signal strength wake-up method is that t can take a relatively small value. In the current technical case, the t value takes 2~4ms. Another advantage is that the implementation is relatively simple, but its shortcomings are many, mainly:

1) The anti-interference ability is poor, especially the influence of the same frequency and adjacent frequency interference is fatal, and the continuous interference will cause continuous false wake-up to the slave device, resulting in unnecessary consumption of energy; 2) It is impossible to distinguish the identity of the sender of the signal, so it will be easily inadvertently or maliciously awakened by other systems, resulting in unnecessary consumption of energy and a decrease in system reliability;

3) Shorten the communication distance. When the RSSI signal is weak, when the RSSI signal is tested by the receiver of the device, the interference and noise energy will account for a large proportion, and the reliability of the RSSI measurement value will decrease, so it must be set higher. Thresholds can reduce false wake-ups and improve reliability. Setting a high threshold will result in a shorter communication distance. For example, the sensitivity of the receiver is -120DBm, but the threshold must be set to -112DBm, the communication distance is shortened accordingly;

4) The sudden wake-up of sudden interference and noise varies from environment to environment and varies with time (such as sunspot activity:), it is difficult to find a reasonable threshold, calculate and evaluate the false wake-up consumption. Energy is also very difficult.

Third, the shortest packet wake-up method

When a wireless transceiver device in the system has communication requirements, it first transmits a number of shortest data packets. When the receiver periodically receives one packet of data, it considers that there is a communication request at this time, and does not enter sleep temporarily. It is the communication process waiting to enter the next step. This method is the shortest packet wake-up method. This method also has a master-slave relationship. The master device is repeatedly sent the shortest data packet, and the slave device is awakened by the shortest data packet.

Generally, in wireless data communication, the data packet is generally composed of bit synchronization, frame synchronization, data and terminator. The structure diagram is shown in Figure 4. In the NRZ coding system, the bit synchronization code takes the value 1010101010... ...or 01010101..., its function is mainly to enable the receiver's bit synchronization extraction circuit to be reliably locked, and then to generate synchronization by subsequent inertia, which is commonly referred to as training code.

The purpose of frame synchronization is to let the receiver compare the frame sync by scanning to find the starting position of the data portion. The receiver has a bit shift register that shifts once for each bit of data, and puts the newly received data to the lowest bit, and then compares it with a fixed frame sync constant. Synchronous, otherwise continue to receive the next bit and compare.

Data is a valid part of a communication transmission and consists of multiple bytes. The data also contains the length of the data.

For information such as CRC check, if the FEC error correction algorithm is adopted, the data also contains redundant parts of the FEC.

The terminator represents the end of a packet of data.

The shortest packet is the packet with the shortest total length in the case of reliable communication. One of them The length of the synchronization is determined by hardware. Different hardware circuits or different integrated circuits require different number of bit synchronizations to be transmitted, generally between 4 and 16 bytes, which is assumed to be 8 bytes. The frame synchronization is generally 16, 24 or 32 bits. The longer the probability of erroneous synchronization, the lower the frequency, generally 32 bits. The data portion can be 0 bytes or 1 to 3 bytes. If there is no data (0 bytes:), it is impossible to wake up the packet or carry some wake-up parameters or commands. In general, the data part preferably has 1 byte. The terminator may not exist in the shortest packet, and may take 1 byte or 2 bytes. Then the total length of the shortest packet is (in bits)

8*8 + 32 + 2*8 = 112bits

If you follow 19200bps, the time t transmitted is:

t = 112/19200 ~ 5.8ms

The system using the shortest packet wake-up method, the workflow and the signal strength wake-up method are basically the same, as shown in Figure 3, the slave device also works in sleep-received one-sleep-received alternate state, but the duration of its reception must be twice The sending time of the shortest packet in a packet is 2t or more. 2t is the window of the shortest data packet wake-up method. If the baud rate is 19200bps, the window duration should be 12ms. At this time, if the sleep time T is longer, the average power consumption is smaller.

The shortest packet wake-up method has overcome most of the shortcomings of the signal strength wake-up method. If the shortest data packet carries a certain amount of information, the slave device can also be put to sleep during the period of 1^, thereby further reducing power consumption. The shortcoming of the shortest packet wake-up method is that the window duration must be 2t or more to ensure that the slave device is reliably woken up. Summary of the invention

The technical problem to be solved by the present invention is to provide a wake-up method for all the wireless communication devices involved in the above-mentioned communication in the prior art that must be synchronized in time, have poor anti-interference ability, and have a long receiving window time to make power consumption large. There is no need to synchronize all communication devices in time, strong anti-interference ability, and short receiving window time to make power consumption low.

The technical solution adopted by the present invention to solve the technical problem is to construct a wake-up method for waking up at least one slave device when the master device has a communication requirement, and the wake-up method includes:

The master device converts the pseudo-random sequence code into a wake-up bit stream by coding when there is a communication requirement, and then Modulating the wake-up bitstream into a wireless modulated signal, and continuously transmitting the wireless modulated signal to at least one slave device for a preset duration, the preset time being greater than or equal to a sleep period of the slave device And the sum of the detection periods, the sum of the sleep period and the detection period constitutes a sleep wake-up period; each slave device receives the wireless modulated signal during the sounding period, and demodulates the wireless modulated signal into a wake-up bit stream, and then The wake-up bit stream is sampled and decoded, and it is determined whether to wake up the slave device according to the decoding result.

In the awake method of the present invention, the pseudo random sequence code is an M sequence.

In the wake-up method of the present invention, the pseudo-random sequence code is pre-stored or generated by a pseudo-random generator.

In the wake-up method of the present invention,

The master device performs the process of converting the pseudo random sequence code into a wake-up bit stream by encoding, and the method further includes: scrambling the pseudo-random sequence code or the bit stream;

The method further includes: descrambling the pseudo-random sequence code in the process of sampling and decoding the wake-up bitstream by the device.

In the awake method of the present invention, the step of determining, by the device, whether to wake up the slave device according to the decoding result includes:

Counting the number of consecutive output 0 after decoding;

It is judged whether the number of consecutive output 0 exceeds a preset limit, and if so, the slave device is woken up; if not, the sleep state is continued.

In the wake-up method of the present invention, the master device inverts the pseudo random sequence code or the wake-up bit stream in the process of encoding or modulation;

The step of determining, by the device, whether to wake up the slave device according to the decoding result includes:

Counting the number of consecutive outputs 1 after decoding;

It is determined whether the number of consecutive outputs 1 exceeds a preset limit, and if so, the slave device is woken up; if not, the sleep state is continued.

In the wake-up method of the present invention, the slave device calculates the waiting time according to the position of the decoded pseudo-random sequence code in a pseudo-random sequence period, and continues to maintain the sleep state when the waiting time has not arrived; Upon arrival, the slave device is woken up. In the wake-up method of the present invention, the code is a non-return to zero code, a return-to-zero code, or a Manchester code.

In the wake-up method of the present invention, the modulation is amplitude shift keying, frequency shift keying or phase shift keying.

The present invention also contemplates a wireless communication system including a master device and at least one slave device, the master device comprising:

a coding unit, configured to encode a pseudo-random sequence code into a wake-up bitstream when there is a communication requirement; and a modulating unit, configured to modulate the wake-up bitstream into a wireless modulated signal;

a sending unit, configured to continuously send the wireless modulation signal to at least one slave device for a preset duration, where the preset time is greater than or equal to a sum of a sleep period and a detection period of the slave device, The sum of the sleep period and the detection period constitutes a complete sleep wake-up period;

Each slave device includes:

a receiving unit, configured to receive the wireless modulated signal during a sounding period;

a demodulation unit, configured to demodulate the wireless modulated signal into a wake-up bitstream;

a decoding unit, configured to sample and decode the wake-up bitstream;

And a wake-up control unit, configured to determine, according to the decoding result, whether to wake up the slave device.

The technical solution of the present invention has the following beneficial effects:

1. There is no need to synchronize in time between wireless communication devices participating in communication;

2. Strong anti-interference ability, solve the problem of identification and false wake-up, and improve reliability;

3. It can shorten the detection period of the slave device, reduce the receiving window time from the device, and reduce the power consumption of the communication system. DRAWINGS

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a timing chart of the operation of the first wake-up method of the prior art;

2 is a timing chart of operation of a second wake-up method of the prior art;

3 is a timing chart of the operation of the third wake-up method of the prior art;

4 is a structural diagram of a data packet in a third wake-up method in the prior art; FIG. 5 is a flowchart of Embodiment 1 of a wake-up method according to the present invention; FIG.

6 is a structural diagram of Embodiment 1 of a linear feedback shift register in a master device of the present invention; FIG. 7 is a structural diagram of Embodiment 1 of a linear feedback shift register in a slave device of the present invention; FIG. 8 is a first embodiment of a wake-up method according to the present invention; Working sequence diagram

Figure 9 is a logic diagram of a first embodiment of the wireless communication system of the present invention. detailed description

As shown in FIG. 5, in the flowchart of Embodiment 1 of the awake method of the present invention, the waking method is used to wake up at least one slave device when the master device has a communication requirement, and specifically includes the following steps:

Step S100. The master device converts the pseudo-random sequence code into a wake-up bit stream by coding when there is a communication requirement, and then modulates the wake-up bit stream into a wireless modulated signal, and to the at least one slave device within a preset duration. And continuously transmitting the wireless modulation signal, where the preset time is greater than or equal to a sum of a sleep period and a detection period of the slave device, and a sum of the sleep period and the detection period constitutes a sleep wake-up period;

Step S200. Each slave device receives the wireless modulation signal during a sounding period, and demodulates the wireless modulation signal into a wake-up bit stream, and then samples and decodes the wake-up bit stream, and determines according to the decoding result. Whether to wake up the slave device.

The pseudo-random sequence code is preferably an M-sequence (longest sequence), and of course other sequences that meet the requirements may be selected. The use of the M sequence results in a better performance, and the present invention can also be implemented using other sequences, and is also within the scope of the present invention.

In step S100, the pseudo-random sequence code may be pre-stored or may be generated by a pseudo-random generator. The following describes the basic principle of the pseudo-random sequence:

The M-sequence generator is usually implemented by a linear feedback shift register (LFSR), which generates a set of pseudo-random sequences with the longest period. The characteristic polynomial is usually used to represent the structure of the LFSR. If the characteristic polynomial is a primitive polynomial, The resulting sequence is the M sequence, and the characteristic polynomial is expressed as follows: f(x) = c ₀ +CiX+c ₂ x ² +...+ c _n x ⁿ (2.2.1-1)

Where: n is the order of the LFSR, and the maximum period of the n-order binary linear m-sequence is N=2 ⁿ -1. Figure 6 is a structural diagram of a linear feedback shift register (n-order M-sequence pseudo-random generator), in the figure ao, ^...^ The initial values cannot all be 0. Figure 6 can also be expressed as an equation:

3⁄4 = Ci i ® ο ₂ 3⁄4 _-2 © ... © c _n- iai ® c _n a ₀ (2.2.1-2)

In the formula (2.2.1-2), @ denotes the modulo 2 plus or XOR, and the right part of the formula is moved to the left, and a new equation is obtained:

a _n ® cia _n- i ® c ₂ a _n-2 © ... ® c _n- iai ® c _n ao = 0 (2.2.1-3)

As shown in Figure 7, we can get a new linear feedback shift register with input according to equation (2.2.1-3). When the values of _Ci in the equation (2.2.1-2) are the same, the shift register can be used as a decoding circuit of the pseudo-random generator, and the initial value can be any value. When n values are entered and all initial values in the register are removed, their output is always zero.

The wake-up method of the present invention will be described below with reference to FIG. 8. First, the order and characteristic polynomial of the LFSR in the master device are the same as the order and characteristic polynomial of the LFSR in the slave device, respectively, to ensure the editing of the LFSR of the master-slave device. / Decoding polynomial matching, in order to output a continuous 0, which is recognized by the receiver, wakes up from the sleep state, and solves the identification problem. If a random code is generated due to noise, substituting into (2.2.1-3), the probability of continuous output 0 decreases as the order increases. When the order of the LFSR is sufficiently high and the number of consecutive outputs 0 is required to be sufficient, the probability that the decoder continuously outputs multiple zeros due to noise is almost zero, thus solving the problem of noise interference (false wake-up:).

As shown in Figure 8, the following describes the workflow of the master device and the slave device:

First, the workflow of the master device is explained: When the master device has communication requirements, the pseudo-random sequence code is encoded into a wake-up bit stream, and then the wake-up bit stream is modulated into a wireless modulated signal for a preset duration! The wireless modulation signal is continuously transmitted to at least one slave device, and the pseudo random sequence code is generated by an LFSR pseudo-random generator. The LFSR needs to be initialized before starting, but not all 0s. The time of continuous delivery! ^ Τ + t, where T is the dormant period, t is the probing period, and the sum of the dormant period and the probing period constitutes a dormant wake-up period. After the master device sends the wake-up bit stream, it assumes that other slave devices are woken up, immediately enters normal communication, and performs data exchange with the slave device for a duration of T _e . After the data exchange is completed, the slave device goes to sleep. For a slave device that fails communication, such as slave device 3, the master device needs to initiate an error handling mechanism for processing.

The workflow for each slave is described below:

Step 1. The slave device operates at a fixed period Τ+t, alternately works on sleep, receives one sleep, and receives one. status. During the time T, the slave device is dormant, does not receive any data, and the sleep current is extremely low, reaching several microamps or less;

Step 2. During time t, the slave device is in the probing state and starts the decoder. Each time a bit of data is received, 1 bit is output. A counter is started at the same time. When the output bit is 1, the counter is cleared. When the output bit is 0, the counter is incremented by 1. During the received time t, when the value of the counter is always less than the set threshold value M, it means that no wake-up signal is received, the slave device goes to sleep, and the step U is repeated.

Step 3. When the value of the counter is greater than or equal to the threshold within the received time t, it indicates that the wake-up signal is received, and the slave device enters the waiting for a valid communication state, and the waiting time is T _w . Between T\J3⁄4, the slave device is still receiving, but cannot communicate normally, and the energy during this period is wasted. If an inverse increase, according to the pseudo-random sequence code decoding position in a pseudo-random sequence period, calculate a value for the waiting time T _w, it is also possible to enter the device from the waiting time T \ between J¾ In the sleep state, the wakeup signal is sent on the master device! At the end, the slave device wakes up by timing, which further saves energy;

Step 4. Waiting time 1^ After the arrival, the master and slave devices can perform the scheduled normal communication. After the communication ends, the slave device proceeds to step 1. If there is a problem such as a communication error, the error processing flow is entered.

It should be specially stated that when the slave device receives the wake-up bit stream, it generally requires the master device to first transmit a string of bit synchronization codes, and the slave device calibrates the time reference and the clock frequency according to the serial bit synchronization code. In the present invention, the pseudo-random sequence transmitted by the master device, within a length of code length, the number of 0s and the number of ones are substantially equal, and there is no longer continuous 0 or continuous 1 case, which can be used as a bit. Synchronous use, but the effect is slightly worse than sending a regular 01010101010···0101 code. If the bit-synchronous separation circuit is required to transmit a higher quality bit-synchronous training code in the receiving circuit of the slave device, then Manchester code can be used to solve this problem, enabling the receiver to separate higher-quality bit synchronization.

The wake-up method is exemplified below. Here, the value of the window (probing period) t in the system using the present invention is calculated by taking the baud rate of 19200 bps as an example. Assuming a LFSR of order _n = 20, the polynomial is preferably a primitive polynomial. Then, when the master device sends the wake-up signal, first initialize the value of each register (not all 0), and then according to the 19200 bps synchronous clock, the sequence code generated by the LFSR is modulated and sequentially transmitted for a duration of T _s . The value of T _s is based on the requirements for power consumption and other requirements. Ok. From the device to the sleep state, the slave device generally waits for 8 bytes of time, and the receiver's synchronous separation mechanism can separate stable bit synchronization. At the same time, start to input the correct symbol received to the LFSR decoder. After shifting input n bits (here _n = 20), each register of the decoder is received with the correct data refresh, the old one is not The correct data was removed. At this time, the LFSR starts to output 0. When M 0s are continuously output (M can be equal to n, or can be slightly larger than, or slightly smaller than n, determined in different applications, here M=n), the wake-up signal is found. The time it takes from wake-up to find the wake-up signal is:

t = (8*8+n+M)/19200 = (8*8+20+20)/19200 = 5.4Ms

This time, which is the window time t of the present invention, does not need to be doubled, and the value may be slightly longer, such as 5.8 Ms or 6 Ms, which is twice the window time of the minimum packet wake-up method. That is to say, the timing is started from the time when the device is switched from sleep to reception. If the wake-up signal is not detected within 5.8Ms, it goes to sleep again. Some receivers' synchronous separation circuits are more efficient, and the bit synchronization can be separated within 3~4 bytes, then the t value can be controlled within 4Ms. A series of chips compatible with the CC1100 or RF-compatible with the CC1100, produced by TI Texas InstruMent.

Preferably, in the process of converting the pseudo random sequence code into a wake-up bit stream, the method further includes: scrambling the pseudo-random sequence code or the bit stream; correspondingly, the slave device is in the pair In the process of sampling and decoding the wake-up bitstream, the method further includes: descrambling the pseudo-random sequence code.

In an alternative, the master device negates the pseudo-random sequence code or the wake-up bitstream in the encoding or modulation step. Correspondingly, the step of determining, by the device, whether to wake up the slave device according to the decoding result includes:

Counting the number of consecutive outputs 1 after decoding; determining whether the number of consecutive outputs 1 exceeds a preset limit, and if so, waking up the slave; if not, continuing to remain in a sleep state.

In the above embodiment, the code mentioned may be a non-return-to-zero code NRZ, a return-to-zero code RZ, a Manchester code, etc., especially a Manchester code, which is more advantageous for synchronous separation circuits of multiple slave devices. Or a synchronous separation mechanism that quickly and accurately separates the synchronized clock of the received bit stream. The modulation mentioned can be in any binary or multi-modulation mode, such as amplitude shift keying ASK, frequency shift keying FSK or phase shift keying PSK, etc., or other modulation methods that will wake up the bit stream (baseband signal) directly. Or Ground modulation to any carrier frequency.

In the logic diagram of the first embodiment of the wireless communication system of the present invention shown in FIG. 9, the wireless communication system includes a master device 100 and a slave device 200. It should be noted that although this embodiment only shows one slave device, The present invention is not limited to the number of slave devices, it being understood that the logical structure of the other slave devices is the same as the logical structure of the slave device 200. In the wireless communication system, the master device 100 includes a coding unit 110, a modulation unit 120, and a transmitting unit 130, which are sequentially connected, and the slave device 200 includes a receiving unit 210, a demodulating unit 220, a decoding unit 230, and a wake-up control unit that are sequentially connected in sequence. 240. In the master device 100, the encoding unit 110 is configured to encode the pseudo random sequence code into a wake-up bit stream when there is a communication requirement; the modulating unit 120 is configured to modulate the wake-up bit stream into a wireless modulated signal; and the transmitting unit 130 is configured to And transmitting, by the at least one slave device, the wireless modulation signal continuously for a preset duration, where the preset time is greater than or equal to a sum of a sleep period and a detection period of the slave device, where the sleep period and the detection period are And constitute a complete sleep wake-up cycle. In the slave device 200, the receiving unit 210 is configured to receive the wireless modulated signal during a sounding period; the demodulating unit 220 is configured to demodulate the wireless modulated signal into a wake-up bitstream; and the decoding unit 230 is configured to The bit stream is sampled and decoded; the wake-up control unit 240 is configured to determine whether to wake up the slave device according to the decoding result. It is explained here that each step in the preferred embodiment of the wake-up method has a corresponding functional module in the wireless communication system, which will not be described herein.

It should be noted that, in the communication system of the present invention, the roles of the master device and the slave device can be interchanged, which device initiates communication, and which device is a slave device, and its identity is not a constant layer. In addition, the master device may or may not have a receiving unit, i.e., the master device may be a simplex (transmit only), half duplex, or full duplex device. The slave device may or may not have a transmit unit, but must have a receive unit, ie the slave device can be a simplex (receive only), half-duplex or full-duplex device.

There are many methods that can be employed to implement the present invention. For example, ordinary hardware logic circuits, PAL, GAL, CPLD and other programmable devices, FPGA field programmable gate arrays, software programming, and the like can also be used. When the communication speed is low and the processing power of the MCU is sufficient, the software implementation is preferred to reduce costs and achieve better flexibility. When the communication rate is high, it needs to be implemented by a hardware circuit. However, no matter which method is adopted, it is within the scope of protection of the present invention. The inventor has adopted the RF device CI 100E produced by Texas Instruments (Texas InstruMent), and cooperates with ATMEL of the United States. The company's microprocessor Mega48 fully implements the above functions.

The beneficial effects of implementing the technical solution of the present invention are as follows:

1. Compared with the minimum packet wake-up method, since the window time (probing period) is reduced by about half, the power consumption of the communication system is reduced, and the battery-powered wireless communication device is prolonged;

2. Improve the reliability of the communication system, and can be reliably awakened in the case of low power consumption of sleep;

3. When waking up, identify the identity and avoid false wake-up;

4. The confidentiality is good. As long as the order is high enough, the polynomial used is difficult to be restored.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalents, improvements, etc., made within the spirit and scope of the invention are intended to be included within the scope of the appended claims.

Claims

Rights request

A wake-up method for waking up at least one slave device when the master device has a communication requirement, wherein the wake-up method includes:

The master device converts the pseudo-random sequence code into a wake-up bit stream by coding when there is a communication requirement, and then modulates the wake-up bit stream into a wireless modulated signal, and continuously transmits to the at least one slave device within a preset duration. The wireless modulation signal, the preset time is greater than or equal to the sum of the sleep period and the detection period of the slave device, and the sum of the sleep period and the detection period constitutes a sleep wake-up period; each slave device receives during the sounding period The wirelessly modulating the signal, and demodulating the wireless modulated signal into a wake-up bitstream, then sampling and decoding the wake-up bitstream, and determining whether to wake up the slave device according to the decoding result.

2. The wake-up method according to claim 1, wherein the pseudo-random sequence code is an M-sequence.

3. The wake-up method according to claim 1, wherein the pseudo-random sequence code is pre-stored or generated by a pseudo-random generator.

4. The wake-up method according to claim 1, wherein:

The awake method according to any one of claims 1 to 4, wherein the step of determining, by the device, whether to wake up the slave device according to the decoding result comprises:

Counting the number of consecutive output 0 after decoding;

The awake method according to any one of claims 1 to 4, wherein the master device inverts the pseudo-random sequence code or the wake-up bit stream in the process of encoding or modulating;

The step of determining, by the device, whether to wake up the slave device according to the decoding result includes: Counting the number of consecutive output 1 after decoding;

7. The wake-up method according to claim 1, wherein the slave device calculates the waiting time according to the position of the decoded pseudo-random sequence code in a pseudo-random sequence period, and continues to hold when the waiting time is not reached. Sleep state; wakes up the slave when the wait time arrives.

The wake-up method according to claim 1, wherein the encoding is a non-return to zero code, a return-to-zero code, or a Manchester code.

The wake-up method according to claim 1, wherein the modulation is amplitude shift keying, frequency shift keying or phase shift keying.

10. A wireless communication system, comprising a master device and at least one slave device, wherein the master device comprises:

Each slave device includes:

a decoding unit, configured to sample and decode the wake-up bitstream;