CN106326795A - Method for solving RFID technology signal interference - Google Patents

Abstract

The invention discloses a method for solving signal interference of RFID technology. Before the reader communicates with the electronic tag, it must wait at least tmin in the waiting state, and the time is equal to three times the beacon interval time; if the reader is within the time tmin When the consumption is over and no beacon is received, the reader begins to judge whether there are other readers reading electronic tags around it, so the reader enters the competition stage, and randomly selects a backoff time from the time interval; when the reader and When the tag communicates, the reader sends a beacon every other beacon interval on the control channel; every time the reader sends a beacon, it first detects the control channel; once it detects that the control channel is idle, the reader waits for a period of time. Randomly delay and check the channel and send the beacon again. The radio frequency identification system of the invention has small error rate, fast identification speed and large effective identification distance.

Description

A method to solve RFID technology signal interference

technical field

The invention belongs to radio frequency identification technology, and relates to a method for solving signal interference of a reader in a radio frequency identification system by means of distributed communication, in particular to a method for solving signal interference of RFID technology.

Background technique

Radio Frequency Identification (RFID) is an information collection and processing technology, which has the advantages of fast speed, accurate information, and instant communication. With the continuous development of this technology, the privacy security problem of RFID is becoming more and more serious, that is, any transponder can be scanned by a reader (card reader) with the same frequency. The speed is slow and the effective recognition distance is reduced. Therefore a method is needed to avoid signal interference between readers.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a method for solving the signal interference of RFID technology. By adopting this method, the bit error rate of the radio frequency identification system is small, the identification speed is fast, and the effective identification distance is large.

The object of the present invention is achieved through the following technical solutions:

A method for solving RFID technology signal interference, characterized in that: the method uses a distributed communication method to solve reader signal interference in a radio frequency identification system, specifically as follows:

1) Before the reader communicates with the electronic tag, it must wait for at least tmin in the waiting state, which is equal to 3 times the beacon interval time; in this state, every time the reader receives a beacon, it resets the waiting time for tmin;

2) If the reader has not received any beacons after tmin is exhausted, the reader starts to judge whether there are other readers reading electronic tags around it, so the reader enters the competition stage and randomly selects from the time interval Extract a backoff time; if i is selected, the reader must wait for i beacon time intervals in a competitive state; if the reader receives a beacon, it exits the current cycle and waits in the next cycle; if the random backoff time ends The reader has not received the beacon, then the reader will think that there is no other reader competing with it; therefore, the reader sends information on the control channel and communicates with the tag on the data channel at the same time;

3) When the reader communicates with the tag, the reader sends a beacon every other beacon interval on the control channel; the beacon notifies nearby readers, preventing them from communicating with the tag, avoiding conflicts This is the so-called signal interference; after the communication with the tag ends, the reader returns to the waiting state and continues to wait for the remaining cycle;

4) Every time the reader sends a beacon, it first detects the control channel; if the control channel is busy, the reader will continue to detect; once it detects that the control channel is idle, the reader waits for a random delay and detects again Channels and beacons are sent; if the interrogator receives a beacon during the backoff time of the contention phase, it stores the remaining backoff time and waits for the next opportunity.

The invention solves the signal interference of the reader in the radio frequency identification system, so that the radio frequency identification system has a small bit error rate, a fast recognition speed and a large effective recognition distance.

Description of drawings

FIG. 1 is a schematic diagram of a control channel range in a distributed communication mode.

Fig. 2 is a flow chart of the distributed communication mode.

detailed description

Since the electronic tags of radio frequency identification are passive, they cannot participate in the anti-jamming of the signal. There are hidden nodes in the RFID system, as shown in Figure 1. R1 and R2 are not in mutual listening range, but at E the signal transmitted from reader R1 interferes with the signal transmitted from reader R2. In this case, a communication mechanism is needed between R1 and R2. The main purpose of this communication mechanism is that when the reader R1 and the electronic tag E are communicating, the reader R2 is notified that R1 is communicating, so R2 can Delay the communication with electronic tag E. When a reader is communicating with the electronic tag, it will periodically send information in an independent control channel, and the information is mainly sent by broadcast. In Figure 1, although R1 and R2 interfere with each other on the data channel, they communicate on the control channel, which is achieved by transmitting higher power on the control channel than the data channel.

A method for solving signal interference of RFID technology, the method adopts distributed communication method to solve the signal interference of readers in radio frequency identification system, Fig. 2 is a flow chart of distributed communication method. details as follows:

Step 1: Before the reader communicates with the electronic tag, it must wait for at least tmin in the waiting state, which is equal to three times the beacon interval time. In this state, every time the reader receives a beacon, it resets the waiting time to tmin.

Step 2: If the reader has not received any beacons within the duration of tmin, the reader starts to judge whether there are other readers reading electronic tags around it, so the reader enters the competition stage, and from the time interval Randomly pick a backoff time. If i is chosen, then the reader must wait for i beacon intervals in a race condition. If the reader receives a beacon, it exits the current cycle and waits in the next cycle. If the random backoff time expires and the reader has not received a beacon, then the reader assumes that no other readers are competing with it. Therefore, the reader sends information on the control channel while communicating with the tag on the data channel.

Step 3: When the reader communicates with the tag, the reader sends a beacon every other beacon interval on the control channel. The beacon notifies nearby readers and prevents them from communicating with the tag, thus avoiding collisions known as signal jamming. After the communication with the tag ends, the reader returns to the waiting state and continues to wait for the remaining cycles.

Step 4: Every time the reader sends a beacon, it first detects the control channel. If the control channel is busy, the reader will keep checking. Once it detects that the control channel is idle, the reader waits for a random delay and checks the channel again and sends a beacon. If the interrogator receives a beacon during the backoff time of the contention phase, it stores the remaining backoff time and waits for the next opportunity.

Claims (1)

1. the method solving rfid signal interference, it is characterised in that: the method uses distributed communication mode to solve Certainly reader signal interference in radio-frequency recognition system, specific as follows:

1) reader is before communicating with electronic tag, it is necessary to wait at least for tmin duration in waiting state, and this duration is equal to 3 times The beacon interval time；In this state, reader often receives a beacon, and its waiting time that again resets is tmin；

2) if reader is at duration tmin internal consumption does not the most receive any beacon, reader starts to judge in its week Enclosing the reader whether having other at read electronic label, then reader enters the competitive stage, and from time interval with Machine one back off time of extraction；If selecting i, so reader must wait i Beacon Periods in race condition；If Reader receives a beacon, and it just exits the present cycle, waits at next cycle；If random-backoff time terminates Reader is also not received by beacon, then this reader just will be considered that reader and its competition not having other；Therefore, this is read Read device and send information the most on a control channel, communicate with label in data channel simultaneously；

3) when reader communicates with label, reader sends one every a beacon interval duration on a control channel Beacon；Reader near this beacon announcement, stop and communicate between they and label, it is to avoid conflict i.e. so-called Signal disturbing；After terminating with label communication, reader comes back to waiting state, continues waiting for the remaining cycle；

4) reader often sends a beacon, first detection control passage；If controlling passage to be in busy condition, then reader Can detection go down always；Once detecting that control passage is in not busy state, reader waits for a random delay and examines again Survey passage and send beacon；If the back off time that read write line is in the competitive stage receives beacon, it will store remaining moving back Keep away the time, and wait chance next time.