KR100780006B1 - The wireless share device of printer with industrial scientific medical band - Google Patents

Abstract

The present invention relates to a printer wireless router which eliminates crosstalk and interference in an ISM band, and more particularly, to a wireless communication method using an ISM band for improving a data transmission rate, and more particularly, in a wireless communication method using an ISM band. Receiving a radio signal transmitted at a constant frequency through a certain channel, searching for an error of the received radio signal, comparing the error and the reference value according to the search result and switching the frequency according to the comparison result It includes the step of receiving data at the received frequency, which can improve the data transmission efficiency, simplify the processing for data transmission, and eliminate the crosstalk and interference in the ISM band that can prevent data loss and malfunction. The purpose is to provide a wireless router.

ISM Band, Printer Wireless Router

Description

Printer wireless router eliminates crosstalk and interference in the ISM band {THE WIRELESS SHARE DEVICE OF PRINTER WITH INDUSTRIAL SCIENTIFIC MEDICAL BAND}

1 is a block diagram showing a printer wireless router to remove crosstalk and interference in the ISM band according to the present invention

2 is a flow chart illustrating a method for removing crosstalk and interference in the ISM band of printer wireless sharing in accordance with the present invention.

＊ Explanation of symbols on main parts of drawing

21: RF Transmitter and Receiver 22: IF Amplifier

23: baseband processing unit 24: control unit

25: frequency synthesizer

The present invention relates to wireless communication, and more particularly, to a wireless communication method using an Industrial Scientific Medical (ISM) band.

In general, various kinds of frequency bands are used for wireless communication, and in order to use a certain frequency, a license must be obtained. As a result, the cost burden for communication increases, and thus the demand for ISM rapidly increases, which can be used by anyone without permission. Doing.

However, since ISM is a common communication frequency, there are numerous obstacles of noise and wireless environment, and many methods have been studied to remove them. Frequency hopping). In particular, in the 2.4 GHz band, a frequency hopping scheme is widely adopted and is typically used for a printer wireless router using a wireless LAN.

Hereinafter, with reference to the accompanying drawings, a case of using the frequency hopping method of the wireless communication method using the ISM band of the printer wireless router according to the prior art as follows.

channel Frequency number A 2 4 6 8 10 One 3 5 7 B 8 5 2 10 7 4 One 9 6 C 4 8 One 5 9 2 6 10 3 D 3 6 9 One 4 7 10 2 5

First, frequency hopping resets a communication frequency according to a certain hopping pattern, and shows an example of a hopping pattern in Table 1. In this case, the frequency numbers 1 to 10 mean different frequencies in the ISM band.

As shown in Table 1, the hopping pattern is set so that the same frequency does not become the same between different channels at the same time. The frequency hopping is repeated according to the hopping pattern at least 2.5 times per second. That is, in case of performing communication using 'A' channel, when frequency hopping starts, 2 → 4 → 6 → 8 → 10 → 1 → 3 → 5 → 7 → 2 → 4 → 6. Communication is performed in the order of communication frequency, and assuming hopping is performed three times per second, the frequency is changed in order of 2, 4, 6 for the first 1 second, and 8, 10, 1 for 1 second To change the frequency.

In addition, when performing communication using the 'B' channel, the 'C' channel, and the 'D' channel, the frequency is changed according to each hopping pattern as described above.

Preamble Header Variable data packet Think Start frame delimiter Data packet length Bit rate Error check

In addition, Table 2 shows the format of the data frame to be transmitted. In the conventional data frame, in addition to the variable data packet which is a basic transmission unit of data when performing frequency hopping, the preamble and header are used. ) Is added. At this time, the preamble consists of a 'Sync' bit for synchronizing the transmission timing of the packet and a 'Start frame delimiter' bit for notifying the start of the frame, and the header indicates the length of the packet. It consists of a 'data packet length' bit to inform, a 'bit rate' bit to indicate the data rate and an 'error check' bit to check for data errors.

However, in the conventional wireless router using the ISM band, data may be lost if noise occurs at a specific frequency during frequency hopping or hopping is performed at the same frequency on different channels at the same time. have.

In addition, each time frequency hopping is performed, preambles and headers are added in addition to the data, thereby increasing the amount of data, thereby decreasing the data throughput and eventually reducing the data throughput. Therefore, the length of the data packet is limited, and there is a problem in that a data processing process for transmission is complicated according to the data to be transmitted.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, the printer wireless router is to detect in advance the frequency interference section by the electromagnetic wave generated from other electronic devices in the ISM band by scanning to avoid the section. It is an object of the present invention to provide a signal transmission method that avoids radio interference to allow data to be transmitted by a new hop pattern.

In order to achieve the above object, the printer wireless router which eliminates the interference and interference in the ISM band according to the present invention,

An RF transmitter / receiver 21 for transmitting and receiving radio signals through an antenna therein;

An IF amplifier 22 for converting the output of the RF transmitter / receiver 21 into an intermediate frequency and amplifying it;

A baseband processor 23 for converting the output of the IF amplifier 22 into a baseband signal to enable signal processing at a next stage;

A frequency synthesizer 25 generating a frequency according to a control signal and a state of a communication channel are searched to determine whether or not to frequency hopping according to the result, and when hopping by applying a control signal to the frequency synthesizer 25 to determine the frequency required for hopping Control unit 24 to generate is achieved by being modularized.

In addition, the method for removing crosstalk and interference in the ISM band of the printer wireless router according to the present invention,

Receiving a radio signal transmitted at a predetermined frequency through a predetermined channel of the printer wireless router;

Searching for an error of the received radio signal;

Comparing the error according to the search result with a reference value and converting the frequency according to the comparison result to receive data at the converted frequency;

Comparing the error according to the search result and the reference value and receiving the data at the converted frequency by switching the frequency according to the comparison result, if the error according to the search result is more than the reference value by switching the frequency to receive the data at the converted frequency To do that,

If the error according to the search result is less than the reference value is achieved by including receiving the data continuously over the frequency currently in use without switching the frequency.

Hereinafter, a wireless communication method using an ISM band according to the present invention will be described with reference to the accompanying drawings.

First, the ISM band (Industrial Scientific Medical Band) will be described.

The ISM band (Industrial Scientific Medical Band), originally part of the FCC regulations in the United States, is an industry-licensed and medical-use band that was originally unlicensed with weak field strengths, and is primarily 900 MHz (902 MHz to 928 MHz), 2.4 GHz (2.4 GHz). ~ 2.4835 GHz) and 5.8 GHz (5.725 GHz to 5.825 GHz) are most actively used for wireless LAN applications.

Since it is a license-free band, it can be used for free data communication, can be used all over the world, is easy to install, and can be configured in a small network in a home that can be freely deployed.

Representative wireless LAN standards using the ISM band include 2.1 Bluetooth, HomeRF, IEEE802.11, IrDA, and HIPERLAN.

Method name Bluetooth IEEE 802.11 Home RF IrDA HIPERLAN Transmission speed 1 Mbps (actually 721 kbps) 2 Mbps (IEEE 802.11b: 11 Mbps) 0.8 Mbps, 1.6 Mbps 4 Mbps (advanced IR: 16 Mbps) 23.5 Mbps Frequency band 2.4 GHz band 2.4 GHz band 2.4 GHz band infrared ray 5 GHz vs 17 GHz Modulation method Frequency hopping spread spectrum technology (hopping frequency up to 1600 times per second) Direct spreading and frequency hopping spread spectrum technology Frequency hopping spread spectrum technology (hopping frequency up to 50 times per second) 4-step PPM / 16-step PPM (primary modulation only) Frequency hopping spread spectrum technology Dedicated Voice Channel (Coding by CSVD or logarithmic PCM) radish radish radish 32 kbps ADPCM Transmission distance 10 m (1 mW, 0 dBm), 100 m (100 mW, +20 dBm) 100m (30m for 802.1b) 50 m 3.8m 30 m Primary Modulation GAUSSIAN Freq.Shift Keying (GMSK) BPSK / QPSK and GFSK GFSK remind Diff. GMSK Connection control method Master-Slave, Polling CSMA / CA CSMA / CA, TDMA Pplling EY-NPMA security Standard (Authentication, Encryption) option Standard (Encryption) radish NA

 The present invention provides a printer wireless router that eliminates crosstalk and interference by using the characteristics of the ISM band.

FIG. 2 is a block diagram illustrating a printer wireless router eliminating crosstalk and interference in an ISM band according to the present invention, and FIG. 3 illustrates a method of removing crosstalk and interference in an ISM band of printer wireless sharing according to the present invention. It is a flowchart.

As shown in FIG. 2, the printer wireless router 20 which eliminates crosstalk and interference in the ISM band according to the present invention includes an RF transmitter / receiver 21 for transmitting and receiving a radio signal through an antenna therein and the RF transmitter. IF amplification unit 22 for converting the output of the receiver 21 to an intermediate frequency and amplifying the baseband processing unit for converting the output of the IF amplification unit 22 into a baseband signal for signal processing in the next stage. (23), the frequency synthesizer 25 generating a frequency according to the control signal, the state of the communication channel is searched to determine whether the frequency hopping according to the result, and when hopping by applying a control signal to the frequency synthesizer 25 when hopping The control unit 24 for generating the frequency required for the module is configured and configured.

A detailed operation process of the printer wireless router eliminating crosstalk and interference in the ISM band configured according to the present invention will be described.

As shown in FIG. 3, the control unit 24 is ready to receive data from any one of the wireless communication devices (hereinafter referred to as a first wireless communication device) that performs communication through a predetermined communication network using an ISM band. It outputs a data transmission request signal informing that the signal is received and allocates a channel (S11).

Subsequently, another wireless communication device (hereinafter referred to as a second wireless communication device) receives the data transmission request signal and transmits certain data (S12).

The first wireless communication device receives the data transmitted from the second wireless communication device through the RF transceiver 21, the IF amplifier 22, and the baseband processor 23 (S13).

Subsequently, the controller 24 of the first wireless communication apparatus determines whether an error occurs in the input data (S14).

At this time, the control unit 24 searches for error occurrence by searching for the 'Error check' bit in the data frame format of Table 2 described above.

In operation S14, if an error occurs, it is determined whether the amount of error generated is equal to or greater than the reference value (S15). If the error is greater than or equal to the reference value, the data retransmission signal is output to the second wireless communication device and the frequency synthesizer 25 is output. Frequency hopping is performed by generating a new frequency by applying a control signal to the step (S16). In this case, the frequency hopping does not repeat according to a predetermined hopping pattern as in the related art, but means converting the communication frequency only once.

On the other hand, the determination result (S14) (S15), if the error does not occur or occurs in the received data is less than the reference value does not perform frequency hopping and continues to receive the data by maintaining the original frequency.

Subsequently, it is determined whether the data reception is completed (S17), and if the data reception is not completed, continue searching whether an error occurs in the received data, and if the error occurs again and exceeds the reference value, the frequency hopping is performed again. A series of subroutines S14 to S17 are repeated.

As described above, the present invention searches for a data frame format to determine whether an error occurs in data, and performs frequency hopping only when the generated error is greater than or equal to a reference value to perform communication at a hopping frequency.

As described above, the printer wireless router which eliminates crosstalk and interference in the ISM band according to the present invention performs a frequency hopping only when an error of a reference value or more occurs through an error search, thereby greatly reducing unnecessary additional data. Compared with, it is possible to transmit more data in the same time, thereby improving data transmission efficiency.

In the case of using the frequency hopping method, the length of the data packet is limited because the frequency is continuously switched at a predetermined period. However, in the case of using the communication method according to the present invention, the length of the data packet can be changed because the frequency is maintained until an error exceeding a reference value occurs. Therefore, a series of processes for data transmission can be simplified.

Claims (3)

An RF transmitter / receiver 21 for transmitting and receiving radio signals through an antenna therein; An IF amplifier 22 for converting the output of the RF transmitter / receiver 21 into an intermediate frequency and amplifying it; A baseband processor 23 for converting the output of the IF amplifier 22 into a baseband signal to enable signal processing at a next stage; A frequency synthesizer 25 generating a frequency according to a control signal and a state of a communication channel are searched to determine whether or not to frequency hopping according to the result, and when hopping by applying a control signal to the frequency synthesizer 25 to determine the frequency required for hopping A printer wireless router which eliminates crosstalk and interference in the ISM band, characterized in that the control unit 24 is configured to be modularized. Receiving a radio signal transmitted at a predetermined frequency through a predetermined channel of the printer wireless router; Searching for an error of the received radio signal; In the step of comparing the error according to the search result and the reference value and switching the frequency according to the comparison result to receive the data at the converted frequency, Comparing the error according to the search result and the reference value and receiving the data at the converted frequency by switching the frequency according to the comparison result, if the error according to the search result is more than the reference value by switching the frequency to receive the data at the converted frequency To do that, If the error according to the search result is less than the reference value, the method comprising the step of continuing to receive data through the frequency currently in use without switching frequency, characterized in that it comprises a crosstalk and interference in the ISM band of the printer wireless router. The method of claim 2, When the error according to the search result is greater than the reference value, receiving the data at the converted frequency by switching the frequency further comprises the step of switching the frequency and outputting the data retransmission signal of the printer wireless router, characterized in that How to eliminate crosstalk and interference in the ISM band.

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