KR101031874B1 - Method of acquiring synchronization of data in a two-way radio using high frequency - Google Patents

Abstract

PURPOSE: A method for quickly acquiring synchronization of data in a two-way radio is provided to exactly synchronize data using high frequency. CONSTITUTION: A plurality of wireless processors(501a-501n) outputs the samples of a discrete fourier transform value and a band lowering. A maximum value determiner(503) determines the maximum value in the discrete fourier samples. The maximum value determiner performs hard decision using the determined result. A cyclic type accumulator(505) accumulates the hard decision samples into a symbol unit. A sampling point determiner(507) determines a sampling point by comparing with a predetermined signal.

Description

METHOD OF ACQUIRING SYNCHRONIZATION OF DATA IN A TWO-WAY RADIO USING HIGH FREQUENCY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronization device and a method of controlling the same in a wireless communication device using a short wave frequency, and more particularly, to a synchronization device and a control method of data in a wireless communication device using a short wave frequency.

In general, wireless communication devices start from a device for dialogue between remote locations. A representative device of such wireless communication devices is a radio. The radio is also called a walkie-talkie, meaning it is a two-way communication device that can walk and communicate. These walkie-talkies basically evolved around voice communications, but have been used to telegraph and data communications in addition to voice. Among these radios, radios that use the short frequency frequency (HF, High Frequency) band basically use the amplitude modulation (AM) method and are used in various ways depending on the operation method as communication equipment.

1 is a diagram illustrating a mode according to an operation method of a wireless communication device using an HF band in general, an AM method.

Referring to FIG. 1, basically, an operation method of a wireless communication device using an AM type HF band is largely classified into a fixed method and an automatic method. First, the fixed method is divided into fixed voice, fixed telegraph, and fixed data. The automatic method is divided into standby, measurement (LQA) connection (ALE) leap 1 and leap 2. In automatic connection, fixed voice, fixed telegraph, and fixed data types are classified.

Meanwhile, a synchronization algorithm is required to transmit data in a radio, which is a wireless communication device of the HF band. This is equally necessary for 950K in radios in the HF band.

However, a general 950K synchronization algorithm hardly determines a received data frame, and then, at a bit level, a known signal, for example, a data start sequence (SOD). Synchronization is obtained by comparison with a signal such as sequence). As described above, there are various problems in obtaining synchronization through bit level comparison of a known signal after hard decision.

First, if the channel environment is not good, you cannot synchronize at all.

Second, in contrast, when the channel environment is good, there is a problem in that it is impossible to find an accurate sampling point because several sampling points are acquired.

Accordingly, the present invention provides an apparatus and a control method for accurately obtaining data synchronization in a wireless communication equipment of the HF band.

In addition, the present invention provides an apparatus and a control method thereof that can quickly obtain data synchronization in the wireless communication equipment of the HF band.

In addition, the present invention provides a device for obtaining a synchronization regardless of the channel state in the wireless communication equipment of the HF band and its control method.

An apparatus according to an embodiment of the present invention is a device for acquiring synchronization of a data frame in a receiver of a wireless communication device using a short wave frequency (HF) band, and receives a data signal of the short wave frequency (HF) band. Wireless processing units for outputting the samples of the band down and Discrete Fourier transform value, the maximum value determiner for determining and outputting the maximum value of the sample calculated Fourier Fourier, in the unit of one symbol output from the maximum value determiner And an annular accumulator that accumulates each sample.

A method according to an embodiment of the present invention is a method for acquiring synchronization of a data frame in a receiver of a wireless communication device using a short wave frequency (HF) band, and receives a data signal of the short wave frequency (HF) band. Outputting samples of a band-falling and discrete Fourier transform value, determining and outputting a maximum value of the discrete Fourier computed samples, and accumulating each sample in units of one symbol And determining a sampling point of the data frame using the values of the samples accumulated during the predetermined period.

A method according to another embodiment of the present invention is a method for acquiring synchronization of a data frame in a receiver of a wireless communication device using a short wave frequency (HF) band, and receives a data signal of the short wave frequency (HF) band. Outputting samples of a band-falling and discrete Fourier transform value, determining a maximum value of the discrete Fourier computed samples, hard determining using the determined value, and determining the hard determined samples by one symbol unit And accumulating the values of the samples and comparing the values of the samples accumulated during the predetermined period with a predetermined signal to determine the sampling point.

The synchronization acquisition apparatus and its control method according to the present invention can obtain accurate synchronization of data in a wireless communication equipment of the HF band, can quickly obtain data synchronization, and can acquire synchronization regardless of channel state.

1 is a diagram illustrating a mode according to an operation method of a wireless communication device using an HF band in general, an AM method;
2 is a block diagram of a transmitter for transmitting data in a fixed frequency method in a wireless communication device using an HF band;
3 is an exemplary diagram of a frame configuration for data transmission in a wireless transmission system using the HF band,
4 is a flowchart of a conventional 950K synchronization process in a receiver of a wireless communication device using an HF band;
5 is a block diagram of a receiver for acquiring data frame synchronization in a wireless communication device according to an embodiment of the present invention;
6 is a conceptual illustration showing an annular accumulator configured as a buffer according to a preferred embodiment of the present invention;
7 is a graph of simulation results when the annular accumulator of the receiver according to the present invention is applied to a wireless communication device using an HF band.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be given with reference to the accompanying drawings. Specific details are set forth in the following description, which is provided to provide a more thorough understanding of the present invention. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, a block and frames thereof will be described with respect to a case where data is transmitted in a fixed frequency manner in a wireless communication device using an HF band in order to understand the present invention. In the following description, a radio used as a representative example of a wireless communication device will be described as an example. It should be noted that this is for convenience of understanding and is not limited to radios.

In addition, the reason why the data is transmitted in the fixed frequency method will be described below, since the hopping data method can be understood only by the addition of hopping of the frequency in the radio processing period as compared to the transmission in the fixed frequency method. Note that the fixed frequency method is described for convenience.

2 is a block diagram of a transmitter for transmitting data in a fixed frequency manner in a radio using an HF band.

The data transmitted first is encoded by the encoder 113 according to the transmission rate. The encoded data is then interleaved based on a predetermined interleaving rule. Such interleaving has an effect of preventing cluster error when encoding is performed.

The interleaved data in the interleaver 114 is converted into a symbol of a predetermined format in the symbol generator 115. As such, the data converted into symbols in the symbol generator 115 is composed of frames to be transmitted by the frame configuration unit 116. At this time, the frame configuration unit 116 inserts a start point of data transmission (SOD), a frame synchronization signal (FSYNC), and a field indicating the end of the frame (EOD).

In this way, the signal converted into a frame in the frame configuration unit 116 is provided to the multiplexer 118 after being modulated in a predetermined modulation scheme, for example, an FSK modulation scheme, in the modulator 117a.

Since the radio is also used for fixed telegraph CW, it includes a modulator 117b that modulates the fixed telegraph CW signal when fixed telegraph CW is used. The modulator 117b modulates the fixed telegraph signal to a multiplexer 118 after modulating it with a predetermined modulation scheme, for example, an FSK modulation scheme. Radios are also used in fixed or hopping voices. Thus, the voice signal converted into an electrical signal for transmitting the voice signal is input to the multiplexer 118.

The multiplexer 118 then outputs a voice signal in the current transmission mode, e.g., fixed voice or hopping voice, and outputs a signal of the modulator 117b that modulates the whole body signal in the case of fixed telephony or hopping telegraphy, and fixed data. Alternatively, in the case of the hopping data, the modulator 117a outputs a modulated signal formed of a frame. Since such control is a process performed by a controller not shown in FIG. 1, it will not be described in detail here.

Then, the configuration of the data frame when transmitting data in a fixed frequency method in the radio using the HF band will be described.

3 is an exemplary diagram of a frame configuration for data transmission in a wireless transmission system using the HF band.

As shown in FIG. 3, a data frame basically includes a data start field (SOD, Start Of Data) indicating the start of data, a frame synchronization field (FSYNC) and a data field (Data) to synchronize a frame. Included.

When the data transmission is completed, the data transmission completion field (EOD, End Of Data) is included to notify the completion of data transmission.

As described above, the data start field is always present only at the first position at which the data frame starts, and is a field for notifying that data transmission starts.

Next, the 950K synchronization process in the receiver of the radio using the HF band will be described in more detail to help the present invention.

4 is a flowchart of a conventional 950K synchronization process in a receiver of a radio using an HF band.

First, when a signal of a data frame is received from the transmitter as described above, a discrete Fourier transform (DFT) is performed in step 300. Thereafter, in step 302, the Max value of the DFT-converted signal is compared, and in step 304, a hard decision is made. When the hard decision is made in this way, the bits in which the hard decision is made are input to a shift register.

Each bit data input to the shift register is compared with a known signal, for example, a start data sequence (SOD sequence), in step 308. After the comparison, in step 310, the receiver performs a sampling point check using a preset threshold. If each bit stored in the shift register matches the starting data sequence by a threshold value or larger, it is determined that a sampling point has been obtained. On the other hand, if each bit stored in the shift register does not match the starting data sequence by the threshold value, the process proceeds to step 300 and repeats the process for acquiring the sampling point.

This process is similar to the slot timing (Slot timing), that is, the process of matching the frame as described in FIG. Therefore, it will not be described further here. However, the slot timing is different in that the comparison is performed using the FSYNC sequence instead of the SOD sequence.

As described above, the conventional 950K receiver synchronization algorithm performs synchronization through comparison with a known signal at a bit level, for example, a data start sequence or a frame synchronization sequence. There are several problems because of the acquisition.

That is, in a high signal-to-noise ratio (SNR) environment, since the decision performance is relatively good, there are various sampling points that satisfy the threshold value. That is, there are several sampling points. Therefore, in order to solve this problem, when the threshold is increased, it is very difficult to obtain a sampling point in a low signal-to-noise ratio (Low SNR) environment.

5 is a block diagram of a receiver for acquiring data frame synchronization in a radio according to a preferred embodiment of the present invention.

The received signal r (t) is input to the plurality of wireless processing units 501a, 501b, ..., 501n, respectively. Each of the wireless processors 501a, 501b, ..., 501n is a device for receiving signals according to respective channels, that is, frequencies, in the radio. Each of these radio processing units 501a, 501b, ..., 501n has the same structure and is not related to the present invention. Therefore, only one radio processing unit 501a will be briefly described.

The received signal r (t) is bifurcated and input to the mixers respectively. At this time, each mixer synthesizes and outputs the received signal r (t) and the signal received from the signal generator (not shown) generating a predetermined frequency and. Through this mixing process, the signal is down-converted to a signal of a predetermined band.

In addition, the signals thus output are accumulated for a predetermined period, and each of the accumulated signals is input to the adder by substituting a positive value in the squarer. In this manner, the discrete Fourier transform is performed through accumulation and square addition. Therefore, the signals added by the radio processors 501a, 501b, ..., 501n are input to the maximum determiner 503, respectively.

The maximum value determiner 503 determines and outputs a maximum value for the samples from the discrete Fourier computed values of the symbols. The maximum value of the samples for each of the symbols thus output is input to the annular accumulator 505 according to the present invention.

The annular accumulator 505 should basically consist of as many buffers or memories as can store all the samples output in one symbol. For example, assuming that there are 64 samples per symbol, the annular accumulator 505 should have at least 64 buffers configured as a ring accumulator.

This example will be described with reference to FIG. 6.

6 is a conceptual illustration showing a ring accumulator configured as a buffer according to a preferred embodiment of the present invention.

As shown in FIG. 6, it is assumed that the annular accumulator 601 is composed of 64 buffers, which are annular characteristics and a minimum number of buffers. At this time, when samples in one symbol are stored by the annular accumulator 601, the samples output in the first symbol are sequentially stored in 64 buffers from the 0th buffer to the 63rd buffer. Subsequently, samples output from the next symbol are sequentially stored in the 63rd buffer from the 0th buffer after the 63rd buffer.

That is, the annular accumulator 601 has a cumulative value for the samples output from each symbol when storing the samples for one symbol. In FIG. 6, the graphs shown above the respective buffers are values representing the cumulative maximum value of the samples. Therefore, since the samples of the maximum value output from each symbol are stored, it can be seen that the value of the sample stored in the specific buffer becomes very large as shown by reference numeral 610. In this way, the point having the largest value can be determined as the sampling point.

Let's examine again with reference to FIG.

When the samples are stored in the form as described in FIG. 6, the sampling point determiner 507 thus determines the sampling point from the samples for the symbols stored in the annular accumulator 505. For example, the sampling point determiner 507 may determine, as the sampling point, a sample having a maximum cumulative value among values of each sample accumulated in the annular accumulator 505. That is, a sampling point as shown by reference numeral 610 shown in FIG. 6 may be determined.

This will be described with reference to FIG. 7.

7 is a graph showing simulation results when the annular accumulator of the receiver according to the present invention is applied to a radio using an HF band.

First, the environment used for the simulation in the case of applying the annular accumulator of the receiver according to the present invention will be described first.

The environment used in the simulation was an AWGN channel, the signal-to-noise ratio was SNR 5dB, and the sampling offset was 30. In this case, in the case of the algorithm used in the existing 950K, it is very difficult to obtain a sampling point in the same environment. However, as shown in FIG. 7, when the maximum value determiner 503, the annular accumulator 505, and the sampling point determiner 507 are used, an accurate sampling point can be found.

In summary, the ring accumulation allocates a buffer for the number of samples generated per symbol, takes a discrete Fourier operation for each sample, and sets the maximum value to each buffer of the annular accumulator. Accumulate to find the sampling point. In other words, if one symbol is composed of 64 samples, the receiver implements an annular accumulator with 64 buffers, takes a discrete Fourier transform (DFT) operation for each sample, and accumulates a maximum (max) value into the annular accumulator. Save it. If the maximum value is continuously accumulated, the value of a specific sampling point becomes relatively large, and this sample is determined as the sampling point. At this time, it is desirable to set an appropriate threshold value to accumulate samples.

When the sampling point is determined in this way, the modulation may be performed according to the determined sampling point, and slot timing may be found. The process of finding the slot timing is the same as the process of comparing with a known signal using the shift resist of FIG. 4 described above. Therefore, description thereof will be omitted.

101, 102, 103: Data
111a, 111b: encoder
112: repeater
113, 118: multiplexer
114: interleaver
115: symbol former
116: frame configuration
117a, 117b: modulator
501a, 501b, 501n: radio processing unit
503: maximum value determiner
505, 601: annular accumulator
507: sampling point determiner
610: sampling point

Claims (10)

delete delete delete delete delete delete A method for acquiring synchronization of a data frame in a receiver of a wireless communication device using a short wave frequency (HF) band,
Receiving data signals of the shortwave frequency (HF) band and outputting samples of band-falling and discrete Fourier transform values;
Determining a maximum value of the discrete Fourier computed samples and hard decision using the determined value;
Accumulating the hard-determined samples in a symbol unit;
A method of synchronizing data in a wireless communication device using a shortwave frequency, comprising: determining a sampling point by comparing values of samples accumulated during a predetermined period with a preset signal. The method of claim 7, wherein the preset signal,
A method of synchronizing data in a wireless communication device using a short wave frequency, which is a start data sequence. The method of claim 7, wherein the accumulating each sample comprises:
A method of synchronizing data in a wireless communication device using a short-wave frequency, cyclically accumulating and storing the maximum value samples output per one symbol every sample. The method of claim 7, wherein the sampling point determination,
And determining a location of a sample whose sampling value is greater than or equal to a predetermined threshold value as a sampling point for the predetermined period of time.

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