WO2012171297A1

WO2012171297A1 - Method for awaking signal matching, apparatus and label

Info

Publication number: WO2012171297A1
Application number: PCT/CN2011/082159
Authority: WO
Inventors: 李龙; 贾桂丽; 侯晓凡
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-16
Filing date: 2011-11-14
Publication date: 2012-12-20
Also published as: CN102831364A; CN102831364B

Abstract

Disclosed are a method for awaking signal matching, an apparatus and a label, applied to a radio frequency identification system. The method comprises: a reader sending an awaking signal to a label, the awaking signal being formed of multiple square waves with fixed frequency; the label determining whether the awaking signal is received in a manner of matching square waves, and if it is determined that the awaking signal is received, switching from a dormant state to a working state. Disclosed is a method for solving the problem that an active label is awaken by mistake in a radio frequency identification system, which reduces the cost of the active label, solves the defect that the active label is awaken by mistake, reduces the power consumption of the active label, reduces the volume of the active label, and can satisfy various application scenarios.

Description

Wake-up signal matching method, device and label

Technical field

The present invention relates to the field of radio frequency identification technologies, and in particular, to a wake-up signal matching method, apparatus, and tag. Background technique

Radio Frequency Identification (RFID) is a non-contact automatic identification technology that automatically recognizes target objects and acquires relevant data through radio frequency signals. The identification work can work in various harsh environments without manual intervention. RFID technology recognizes high-speed moving objects and recognizes multiple labels at the same time, making operation quick and easy.

Radio frequency identification systems mainly include tags and readers. RFID includes passive radio frequency identification and active radio frequency identification, the essential difference between the two is at the tag end. The tags are specifically divided into active electronic tags, semi-active electronic tags, and passive electronic tags.

The active electronic tag, also known as the active tag, is powered entirely by the internal battery, and the energy supply of the tag battery is also partially converted into the RF energy required for the tag to communicate with the reader.

The battery power supply in the semi-passive electronic tag only supports the circuit that requires power supply to maintain the data or the auxiliary voltage required for the operation of the tag chip, and the tag circuit that consumes little power itself. The tag is always in a dormant state before it enters the working state, which is equivalent to a passive tag. The internal battery energy consumption of the tag is less than 4, so the battery can last for several years, even up to 10 years; when the tag enters the reading area of the reader When excited by the RF signal from the reader, when entering the working state, the energy exchanged between the tag and the reader supports the RF energy supplied by the reader (reflective modulation mode), and the internal battery function of the tag mainly remedies the tag. The RF field strength at the location is insufficient, and the energy of the battery inside the tag is not converted to RF energy.

Passive electronic tags, also known as passive tags, do not have a built-in battery. When the reader is outside the reading range of the reader, the electronic tag is in a passive state. When the reader is within the read range of the reader, the electronic tag emits RF from the reader. The energy is extracted from the power required for its work. Passive electronic tags are generally used in reverse The modulation mode completes the transmission of the electronic tag information to the reader.

The active electronic tag itself is powered by a battery, has a long read/write distance, a large volume, and a high cost. The disadvantage is that the battery cannot be used for a long time, and the battery needs to be replaced after the energy is exhausted.

Active tags are normally in a low-power standby state. The internal battery energy of the tag is very low. Only a very short period of time is required to consume a limited amount of power. Therefore, the battery life can be very long. The existing active tags can be classified into the following two types according to the wake-up mode: one is to match the wake-up signal through a hardware circuit or a chip; one is implemented by software.

However, the above two kinds of active tags have some shortcomings: the wake-up signals are matched by hardware circuits or chips, but the cost is high, and it is not easy to promote; and the wake-up signals are not basically matched by software. In practical applications, it is often found that other electromagnetic interferences cause the active tags to be awakened by mistakes, such as other electromagnetic interferences, mainly mobile phone signals in space, etc., and it is easy to wake up by mistake, even to wake up as long as there is a signal, then, active The tag is considered to require work, but is actually an invalid interference signal, which causes the tag to consume power and also greatly affects the battery life. Summary of the invention

The technical problem to be solved by the present invention is to provide a wake-up signal matching method, device and tag, which can solve the defect that the active tag is erroneously awakened, and reduce the power consumption of the active tag.

In order to solve the above technical problem, the present invention provides a wake-up signal matching method, which is applied to a radio frequency identification system, and the method includes:

The reader sends a wake-up signal to the tag, and the wake-up signal is composed of a plurality of square waves of a fixed frequency; the tag determines whether a wake-up signal is received by matching a square wave, and if it is determined that the wake-up signal is received, the sleep state is Switch to working status.

Optionally, the step of determining, by the method of matching a square wave, whether the wake-up signal is received includes:

The tag determines whether the number of consecutively matched square waves reaches a predetermined number of matched square waves, and if so, determines that a wake-up signal is received.

Optionally, the step of determining, by the tag, whether the number of consecutively matched square waves reaches a predetermined number of the matched square waves comprises: Determining whether the number of consecutive square wave hopping interrupts reaches a predetermined number of hops, and if so, determining that the number of consecutively matched square waves reaches a predetermined number of matched square waves;

The number of the hops is the number of the matched square waves plus two.

Optionally, the method further includes:

The start timer is interrupted on the rising or falling edge of the second square wave, and the timing of the timer is determined when the rising edge or the falling edge of the Nth square wave is interrupted, and whether the timing is determined according to the timing Satisfying the frequency range of the square wave, if yes, determining that the Nth square wave is matched; if not, determining that the Nth square wave is not matched; wherein N is greater than or equal to 3.

Optionally, the label includes a wake-up signal matching unit,

The wake-up signal matching unit is configured to: determine whether a wake-up signal is received by matching a square wave, and switch from a sleep state to an active state if it is determined that the wake-up signal is received.

Optionally, the wake-up signal matching unit is configured to determine whether a wake-up signal is received by matching a square wave in the following manner:

It is determined whether the number of consecutively matched square waves reaches a predetermined number of matching square waves, and if so, it is determined that the wake-up signal is received.

Optionally, the wake-up signal matching unit is further configured to: start a timer on a rising or falling edge of the second square wave, and determine the timer when the rising edge or falling edge of the Nth square wave is interrupted. The timing time, and determining whether the frequency range of the square wave is satisfied according to the timing time, if yes, determining that the Nth square wave is matched; if not, determining that the Nth square wave is not matched; , N is greater than or equal to 3.

The present invention also provides a wake-up signal matching apparatus for use in a radio frequency identification system, the apparatus comprising a reader and a tag, the reader comprising a wake-up signal transmitting unit, the tag comprising a wake-up signal matching unit, wherein:

The wake-up signal sending unit is configured to: send a wake-up signal to the tag, where the wake-up signal is composed of multiple square waves of a fixed frequency;

Optionally, the wake-up signal sending unit is configured to send to the label by using an air interface command. The wake-up signal;

The wake-up signal matching unit is configured to determine whether the wake-up signal is received according to the following matching square wave: determining whether the number of consecutively matched square waves reaches a predetermined number of matching square waves, and if so, determining that the wake-up is received signal.

The above-mentioned radio frequency identification system solves the method of false wake-up of the active tag, reduces the cost of the active tag, solves the defect that the active tag is erroneously awakened, reduces the power consumption of the active tag, and reduces the volume of the active tag, which can satisfy A variety of application scenarios. BRIEF abstract

The drawings are intended to provide a further understanding of the invention, and are intended to be illustrative of the invention. In the drawing:

1 is a schematic diagram of a matching wake-up signal according to an embodiment of the present invention;

2 is a flow chart of a method for matching a wake-up signal according to an embodiment of the present invention. Preferred embodiment of the invention

In order to solve the problem of false wake-up of the active tag in the radio frequency identification system, the embodiment of the present invention provides a wake-up signal matching method, including: when the reader and the tag communicate, send an air interface command to the tag, and the tag responds to the command of the reader to implement the reader. Communication with the tag; the command sent by the reader is with a wake-up signal, that is, the notification tag is switched from the sleep state to the working state.

Among them, the wake-up signal is generally composed of several square waves of a fixed frequency. In order to better judge whether it is a wake-up signal, the present invention specifically draws four consecutive methods of matching square waves. Since it is a square wave, there is no difference in phase. As long as 6 jumps are interrupted continuously, it can be considered that 4 parties have been completed. Wave matching.

ϋ Change the number Ν and the number of matching square waves η satisfy the relationship of Ν = η + 2.

The number of matching square waves η can be appropriately increased or decreased according to the actual effect.

The matching algorithm of the present invention is mainly divided into the following steps:

In the first step, the first falling edge interrupts do some basic settings, including timer configuration, active electronic tag status settings, and so on.

In the second step, the second falling edge interrupts the timer to start counting.

The timing can be implemented by a hardware timer inside the processor. For example, the configuration register of the software setting timer can start the timer to start counting, and determine the timing time by reading the count value of the timer when needed, that is, The length of time passed.

In the third step, the third falling edge interrupt determines whether a square wave period is satisfied (that is, whether it is matched with the frequency of the wake-up signal), if it is satisfied, the subsequent matching is continued, and if not, the second step is restarted. Match, until timeout, exit.

In the fourth step, the fourth falling edge determines whether two square wave periods are satisfied. If it is satisfied, the subsequent matching is continued, and if not, the user exits and sleeps.

In the fifth step, the fifth falling edge determines whether three square wave periods are satisfied. If yes, the subsequent matching is continued, and if not, the user exits and sleeps.

In the sixth step, the sixth falling edge determines whether four square wave periods are satisfied. If the matching is successful, the physical layer is received, and if not, the sleep is exited.

Among them, the above-mentioned sleep or timeout exit is judged in the loop outside the interrupt, and the interrupt can internally set the corresponding flag to determine the processing flow of the loop, that is: the interrupt internally sets the flag bit if the matching wake-up signal succeeds. The flag is internally judged by the interrupt outer loop. If the judgment flag is set, the matching process is exited and the subsequent data receiving process is performed.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

Referring to Figure 1, the falling edge of the square wave will generate a wake-up interrupt. The timer is set in one interrupt. The count clock frequency set by the timer cannot be too fast, and should match the frequency of the wake-up signal. Generally, it can be set to 0.5-1.5MHz; the second interrupt starts the timer to start counting, the third interrupt reads the count value in the timer, and the time is counted according to the counted count, and then it is judged whether a square wave is satisfied. Frequency range, (Because the counting clock is fixed, it is possible to calculate the elapsed time according to the counting value, that is, the period, the reciprocal of the period is the frequency, and determine whether the calculated frequency satisfies the frequency range of one square wave, and further It is judged whether it is roughly consistent with the frequency of the wake-up signal. If it is satisfied, the matching continues, otherwise it is re-matched. After the above process is repeated, after the four square waves are successfully matched, the wake-up signal is successfully matched, and the radio receiving is turned on for data reception. If there is no matching within a certain period of time, the timeout is exited and the sleep continues.

Referring to FIG. 2, the matching process of the wake-up signal in the embodiment of the present invention is described as follows:

1) After the wake-up interrupt, it is judged whether it is state 0, the first interrupt defaults to state 0, the state before the match is set in state 0, and the tag state is set to 1.

2) Start the timer count in state 1 and set the tag status to 2. In state 1, it will judge whether the entire match times out or not. If it times out, it will sleep, otherwise it will continue to receive.

3) In state 2, it is judged whether a wake-up square wave frequency requirement is satisfied. If it is satisfied, the counting is restarted, and the state is set to 3, otherwise the state is reset to 1 and the reception is continued.

4) In state 3, it is judged whether the two wake-up square wave frequency requirements are met. If it is satisfied, the counting is restarted, and the state is set to 4, otherwise the state is reset to 0 and sleep.

5) In state 4, it is judged whether the three wake-up square wave frequency requirements are met. If it is satisfied, the counting is restarted, and the state is set to 5, otherwise the state is reset to 0 and sleep.

6) In state 5, it is judged whether the four wake-up square wave frequency requirements are met. If it is satisfied, the wake-up signal flag is successfully matched, otherwise the state is reset to 0 and sleep.

If a state other than the above state occurs, it is considered to be an illegal state, and the software performs a reset process. In combination with the above description, the method of the present invention increases the matching process of the wake-up signal, which not only completes the matching of the wake-up signal, but also plays a good synchronous role for subsequent data reception.

In addition, it should be noted that the version coverage area in which the wake-up signal matching is increased is reduced. This is because the energy of the spatial signal will be lost during the propagation process, the signal energy at the edge of the coverage area is the weakest, and the signal received by the tag is also less effective. If the wake-up signal is matched, it is equivalent to the signal effect, so the coverage area of the matching wake-up signal will be reduced under the same conditions. But This change is not very large and can fully meet the requirements of practical applications.

In addition, the embodiment of the present invention further provides a label, where the label includes a wake-up signal matching unit.

The wake-up signal matching unit is configured to determine whether the wake-up signal is received by matching a square wave, and to switch from the sleep state to the active state if it is determined that the wake-up signal is received.

Preferably, the wake-up signal matching unit determines whether the wake-up signal is received by matching a square wave, including:

Preferably, the wake-up signal matching unit is further configured to: when the rising or falling edge of the second square wave is interrupted, the timer is started, and the timer is determined when the rising edge or the falling edge of the Nth square wave is interrupted. a timing time, and determining, according to the timing time, whether the frequency range of the square wave is satisfied, and if so, determining that the Nth square wave is matched; otherwise, determining that the Nth square wave is not matched; wherein, N is greater than Equal to 3.

In addition, the embodiment of the present invention further provides a wake-up signal matching device, which is applied to a radio frequency identification system, the device includes a reader and a tag, the reader further includes a wake-up signal sending unit, and the tag further includes a wake-up signal matching unit, where:

The wake-up signal sending unit is configured to send a wake-up signal to the tag, where the wake-up signal is composed of a plurality of square waves of a fixed frequency;

Preferably, the wake-up signal sending unit is configured to send the wake-up signal to the label by using an air interface command;

The wake-up signal matching unit is configured to determine whether the wake-up signal is received according to the following method of matching a square wave: determining whether the number of consecutively matched square waves reaches a predetermined number of matching square waves, and if so, determining that the wake-up is received signal.

Preferably, the wake-up signal matching unit is further configured to be on a rising or falling edge of the second square wave The timer is started along the interrupt start timer, and the timing of the timer is determined when the rising edge or the falling edge of the Nth square wave is interrupted, and the frequency range of the square wave is determined according to the timing time. If yes, the determination is performed. Matching to the Nth square wave; if not, determining that the Nth square wave is not matched; wherein N is greater than or equal to 3.

The present invention can be applied to different application scenarios. The following uses the national standard electronic non-stop charging application as an example to introduce the application of the present invention in these scenarios.

In the ETC application, the wake-up signal is 15-17 14KHz square waves. After the active tag wakes up, only the wake-up link and the CPU are working. Since the 14K rate is very low, the CPU clock frequency can be reduced as much as possible to save power when just waking up.

Firstly, the matching range is set to 11K-16.7K, and the matching number is 4 14K square waves. Regarding the number of matched square waves, by looking at the receiving waveform of the tag end, the tag will normally receive 7 square waves, and The received waveforms of other antennas are about 5 or so. Through the actual sports car test, it is found that there are still a certain proportion of false wake-ups when matching 3 square waves, and finally it is decided to match 4 square waves to implement software filtering.

A sports car test was carried out on site, and three labels in the car were tested at a speed of 40Km-100Km with a success rate of 100%. It seems that the addition of a 14K matching software version has no effect on the success rate of the transaction.

Finally, the power saving effect of the scheme is analyzed:

The battery power is generally 1500mA/h, and the available ratio is about 0.7, which is 1500 * 0.7 = 1050 mA/h. Each transaction time is 50ms, power consumption is about 30mA, and the ideal number of transactions is about: 1050/ (0.05/3600*30) = 2.25 million times.

If it is always in the wrong wake-up state, the battery's power consumption time is about 1050/16=65.6 hours, that is, it will be out of power for 3 days.

With 14K matching, even in the false wake-up state, the current is only 140uA, which is 1/90 of the previous current, which can last for about 5740 hours. It seems that by mistakenly waking up the match, the battery life becomes about 90 times that of the original, which can meet the actual use requirements.

The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Various other modifications and changes can be made in accordance with the present invention without departing from the spirit and scope of the invention. It is within the scope of the appended claims.

Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any particular combination of hardware and software.

Industrial Applicability The above-mentioned radio frequency identification system solves the problem of false wake-up of active tags, reduces the cost of active tags, solves the defect that the active tags are falsely awakened, reduces the power consumption of the active tags, and reduces the active tag volume. , can meet a variety of application scenarios.

Claims

Claim

A wake-up signal matching method, which is applied to a radio frequency identification system, the method comprising: a reader transmitting a wake-up signal to a tag, the wake-up signal being composed of a plurality of square waves of a fixed frequency; the tag matching a square wave The mode determines whether a wake-up signal is received, and if it is determined that the wake-up signal is received, it switches from the sleep state to the active state.

2. The method of claim 1 wherein

The step of determining whether the wake-up signal is received by the method of matching the square wave comprises: determining, by the tag, whether the number of consecutively matched square waves reaches a predetermined number of matched square waves, and if yes, determining that the wake-up signal is received .

3. The method of claim 2, wherein

The step of determining, by the tag, whether the number of consecutively matched square waves reaches a predetermined number of matched square waves includes:

Determining whether the number of consecutive square wave hopping interrupts reaches a predetermined number of hops, and if so, determining that the number of consecutively matched square waves reaches a predetermined number of matched square waves;

The number of the hops is the number of the matched square waves plus two.

4. The method of claim 2 or 3, further comprising:

5. A tag comprising a wake-up signal matching unit,

6. The label of claim 5, wherein

The wake-up signal matching unit is configured to determine whether a wake-up signal is received by matching a square wave in the following manner: It is determined whether the number of consecutively matched square waves reaches a predetermined number of matching square waves, and if so, it is determined that the wake-up signal is received.

7. The label of claim 6, wherein

The wake-up signal matching unit is further configured to: start a timer on a rising or falling edge of the second square wave to start timing, and determine a timing time of the timer when the rising edge or falling edge of the Nth square wave is interrupted, And determining, according to the timing time, whether the frequency range of the square wave is satisfied, and if yes, determining that the Nth square wave is matched; if not, determining that the Nth square wave is not matched; wherein, N is greater than or equal to 3.

8. A wake-up signal matching apparatus for use in a radio frequency identification system, the apparatus comprising a reader and a tag, the reader comprising a wake-up signal transmitting unit, the tag comprising a wake-up signal matching unit, wherein:

9. The apparatus according to claim 8, wherein

The wake-up signal sending unit is configured to send the wake-up signal to the label by an air interface command;

10. The apparatus according to claim 9, wherein