KR100572051B1 - Apparatus and method for transmitting a wireless data - Google Patents

Abstract

The present invention relates to a short-range wireless data transmission apparatus and method for minimizing data loss due to channel interference. The apparatus basically includes a transmission data generator for adding redundancy to data to be transmitted and outputting the received backward packet. It includes a receiving data processing unit for restoring and outputting the included data to the original data,

Stores the input real-time data in the memory and reads out the amount of real-time data necessary for packetization from the memory and outputs the real-time data to the transmission data generator, each time a real-time data retransmission request of a previous frame is received through a backward packet. A memory controller which checks the amount of change in the stored data and retransmits the real-time data of the previous frame or requests a channel change;

Forward the real-time data output from the transmission data generation unit together with header information and transmit it through a setting channel, and find a channel without channel interference every alternate channel test period, store the channel as an alternate channel, and request a channel change of the memory controller. A transmission / reception controller for changing and controlling a current current setting channel to the replacement channel;

And an RF transceiver for wirelessly interfacing the forward packet and the backward packet with a slave side.

Frequency selection, channel interference, alternate channel.

Description

Short-range wireless data transmission apparatus and method {APPARATUS AND METHOD FOR TRANSMITTING A WIRELESS DATA}

1 is a block diagram of a short-range wireless data transmission apparatus according to an embodiment of the present invention.

2 is an exemplary packet structure transmitted and received between wireless data transmission apparatuses according to an embodiment of the present invention.

3 is a diagram illustrating an alternative channel discovery process required for short-range wireless data transmission according to an embodiment of the present invention.

4 is a diagram illustrating a channel change process when continuous interference occurs in a set channel according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating an alternative channel searching process described with reference to FIG. 3 on a time axis; FIG.

FIG. 6 is a diagram illustrating a channel change process described with reference to FIG. 4 on a time axis; FIG.

The present invention relates to a short range wireless data transmission system, and more particularly, to a short range wireless data transmission apparatus and method required for minimizing data loss.

Spectrum spreading methods used by Bluetooth and WLAN technology using the 2.4 GHz Industrial Scientific Medical (ISM) frequency band include frequency hopping spread spectrum (FHSS) and direct sequence spread spectrum (DSSS). .

The direct spreading method (DSSS) is a method of obtaining a spreading signal by multiplying a spreading code by data, and the frequency hopping method (also known as frequency hopping) is a method of shifting a frequency band according to a spreading code. In particular, the frequency hopping method is a method in which a carrier frequency of a signal to be spread is hopped at a predetermined time interval and transmitted according to a hopping pattern. The frequency hopping method converts a narrowband signal into a wideband signal with a time average. This frequency hopping method creates a random hopping pattern within the ISM band that meets the standards of each country, and transmits data at the frequency that meets the pattern to minimize frequency duplication. In addition, the simple configuration is widely used in low-cost wireless devices (such as Bluetooth).

However, in the general frequency hopping method, since a hopping is performed regardless of the presence or absence of an interference source for all frequency bands, packet loss may occur when hopping at a specific frequency where interference exists. In this case, in case of data (voice, audio, video) that needs to be transmitted in real time, if the error recovery is not performed, the quality is inevitably deteriorated.

In contrast, Bluetooth (Spec. Ver.1.2) monitors a frequency where AFH (Adaptive Frequency Hopping) interference occurs for a certain period of time and then hops away from the frequency.In addition, interference occurs when real-time data is transmitted. If an error occurs, the same data is retransmitted up to two more times.

However, the above countermeasures cannot prevent data loss due to continuous channel interference. This is because even if the same data is transmitted two times, if an error occurs due to continuous channel interference, switching to a new alternative channel may be performed, but previously lost data is already lost.

Accordingly, an object of the present invention is to provide a short-range wireless data transmission apparatus and method thereof capable of minimizing data loss that may be caused by channel interference without hopping a channel.

Furthermore, the present invention provides a short-range wireless data transmission apparatus and method capable of switching to an alternative channel with less channel interference while minimizing data loss that may be caused by continuous channel interference.

An apparatus according to an embodiment of the present invention for achieving the above object is to add an error redundancy to the data to be transmitted by adding a redundancy for restoring and to output error bits by using the redundancy included in the received backward packet A master-side wireless data transmission device including a reception data processing unit for finding and restoring and outputting original data,

Stores the input real-time data in the memory and reads out the amount of real-time data necessary for packetization from the memory and outputs the real-time data to the transmission data generator, each time a real-time data retransmission request of a previous frame is received through a backward packet. A memory controller which checks the amount of change in the stored data and retransmits the real-time data of the previous frame or requests a channel change;

Forward the real-time data output from the transmission data generation unit together with header information and transmit it through a setting channel, and find a channel without channel interference every alternate channel test period, store the channel as an alternate channel, and request a channel change of the memory controller. A transmission / reception controller for changing and controlling a current current setting channel to the replacement channel;

And an RF transceiver for wirelessly interfacing the forward packet and the backward packet with a slave side.

In addition, the present invention is a transmission data generation unit for adding the redundancy for error recovery to the data to be transmitted and output, and the received data to recover the error bit by using the redundancy included in the wireless forward packet to restore the original data A slave side short-range wireless data transmission device including a processing unit,

Storing the real-time data restored by the receiving data processing unit in a memory address indicated by the recording position information in the forward packet, and in the current memory and the subsequent recording position indication information indicating a memory address where real-time data of the subsequent forward packet should be stored. A memory controller which generates and outputs output position indication information of the output real-time data;

A transmission / reception controller configured to variably set a setting channel according to wirelessly received forward packet control information, and to perform subsequent packetization and transmission of subsequent recording position indication information and output position indication information input from the memory controller together with non-real-time data;

And an RF transceiver for wirelessly interfacing the forward packet and the backward packet with a master side.

According to the above-described configuration, the master side designates the location information on the memory in which the real-time data to be transmitted is to be recorded, and the slave side returns the location information to be recorded next to the real-time data. By comparing the information with the returned position information, it is possible to determine whether data is lost due to channel interference and retransmit the data.

The important thing at this point is that the master is buffering real-time data, so that the same data can be repeated while monitoring the amount of data being buffered. By changing the setting channel to an alternate channel and transmitting the data lost first, the result is that the data loss due to channel interference can be prevented.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

First, FIG. 1 illustrates a block diagram of a short range wireless data transmission device according to an embodiment of the present invention, and FIG. 2 illustrates a packet structure transmitted and received between wireless data transmission devices according to an embodiment of the present invention.

For reference, the master-side short-range wireless data transmission apparatus according to an embodiment of the present invention receives real-time data (R / L SURROUND) from a decoder (AC-3) that processes a signal reproduced on an optical medium, for example. Packetized according to the configuration shown in Figure 2 performs the role of short-range wireless transmission. Then, the slave side short-range wireless data transmission apparatus receives and processes the wirelessly transmitted packet, so that audio sound reproduced from an optical medium may be output through a speaker. This process will be described in more detail with reference to the accompanying drawings,

First, the apparatus for short-range wireless data transmission according to an embodiment of the present invention includes a memory controller 100, a memory 110, a transmission data generator 120, a reception data processor 130, a transmission / reception controller 140, and an RF transmission / reception unit ( 150).

When the short range wireless data transmitter operates as a master, the memory controller 100 stores the real time data input from the decoder in the memory 110 and reads out the real time data from the memory 110 as much as necessary to packetize. To be transmitted to the transmission data generation unit 120 to be described later. In addition, when there is a request for retransmission of the real-time data transmitted in the previous frame through the backward packet transmitted from the slave side, the master-side memory controller 100 checks the amount of data change stored in the memory 110 and transmits the real-time data in the previous frame. Re-transmits or performs a role of requesting a channel change to the transmission and reception controller 140.

 The channel change request and the data change amount check stored in the memory 100 will be described later with reference to FIGS. 3 and 4.

On the other hand, if the wireless data transmission device is operating as a slave, the memory controller 100 is a reception data processor 130 to be described later to the memory 110 address indicated by the recording position information in the forward packet transmitted from the master side. ) Stores the real-time data restored in step 2), and the subsequent recording position indication information indicating the memory 110 address where the real-time data of the subsequent forward packet should be stored, and the output position indication information of the real-time data currently being output from the memory 110. It generates and outputs 3 will be described in detail with reference to FIG. 4.

The transmission data generation unit 120 of the master side and the slave side plays a role of adding and outputting redundancy for error recovery to at least data (real time data and non real time data) to be transmitted. The transmission data generator 100 includes a compression unit for compressing real-time data as in a general short-range wireless data transmission apparatus, a scrambler, an RS encoder and an interleaver, and a forward error correction (FEC) encoder for scrambling the compressed real-time data. It includes.

The received data processor 130 finds an error bit by using redundancy included in the received packet (forward packet or backward packet) and restores the original bit to the original data. The received data processor 130 includes a deinterleaver, an RS decoder, a descrambler, a restorer, and an FEC decoder to restore data processed by the transmission data generator 120.

On the other hand, the transmission and reception controller 140 of the master side forwards the real-time data and the non-real-time data input from the transmission data generation unit 120 together with the header information and transmits them through a set channel. In addition, the transmission / reception controller 140 searches for a channel without channel interference at every replacement channel test period and stores the channel as an alternative channel, and recalls a channel (hereinafter, referred to as a configuration channel) currently set when a channel change request is made from the memory controller 100. Communicate with slave by changing to alternate channel. Program data for this purpose is stored in an internal memory provided in the transmission / reception controller 140.

On the contrary, the transmission / reception controller 140 on the slave side variably sets the current setting channel to the replacement test channel or the replacement channel according to the control information in the forward packet transmitted from the master side, and subsequent recording input from the slave side memory controller 100. The position indication information and the output position indication information together with non-real-time data to transmit the packet (backward) packetization.

For reference, the above-described transmission and reception controller 140 is provided with a function for detecting sync information. In FIG. 1, the memory controller 100 and the transmission / reception controller 140 are separately illustrated, but the memory controller 100 and the transmission / reception controller 140 may be implemented as one-chip ICs, and the transmission data generation unit 120 and the reception data may be implemented. The processor 130 may further include a one-chip IC.

On the other hand, the RF transceiver 150, which is present in both the master and slave side short-range wireless data transmitters, serves to wirelessly interface packets with the counterpart transmitters.

Hereinafter, a packet transmitted and received between a master and a slave side short-range wireless data transmitter will be described with reference to FIG. 2.

First, the forward packet transmitted from the master to the slave includes a sync field in which sync information is recorded, a control information field in which communication channel indication information is recorded, and recording position information for indicating a recording position of real time data. And a header field in which output position information for indicating a data output position in the memory is recorded, and a field in which non-real-time data and real-time data are respectively recorded.

In contrast, the backward packet transmitted from the slave to the master includes a sink field in which sink information is recorded, a control information field in which a response message RM is recorded, and subsequent recording position indication information indicating a memory address where real-time data should be stored. And a header field in which output position indication information of real-time data currently output from the memory is recorded, and a field in which non-real-time data is recorded.

For reference, the recording position information and the output position information included in the forward packet are information generated by the master-side memory controller 100 and provided to the transmission / reception controller 140, and subsequent recording position indication information included in the backward packet. And output position indication information are information generated by the slave-side memory controller 100 and provided to the slave-side transceiver controller 140.

In the above, both blocks for processing real-time data and non-real-time data have been described, but the circuit configuration can be changed to suit the use of the master and the slave. That is, when used as a slave, functional blocks for generating real-time data in the transmission data generator 120 should be removed.

Hereinafter, a data transmission method in the short range wireless data transmission device having the above-described configuration will be described.

As an example, the transmission / reception controller 140 of each of the master and slave side short-range wireless data transmitters sets a channel frequency for data packet transmission through a system initialization process. In this way, a channel configured for data packet transmission may be referred to as a configuration channel.

In the embodiment of the present invention, 10 frequencies evenly distributed among 79 frequencies in the 2.4 GHz band, that is, frequencies corresponding to multiples of 8 (0, 8, 16, .., 72) were selected as frequencies for connection attempts. . The reason for this is that since initially operating only at these frequencies, the time for finding a successful transmission / reception frequency is saved. When transmission / reception is successful in one of the above-described frequency channels, the master transmission / reception controller 140 determines the first frequency of the adjacent frequency of the successful transmission / reception in accordance with the determination that adjacent frequency channels do not have interference. Select with).

When the setting channel is selected according to the above-described method, the master and the slave can transmit and receive real time data through the setting channel Fc. That is, real-time data output from the decoder starts to be recorded in the memory 110 through the master side memory controller 100. In the embodiment of the present invention, it is assumed that the size of real-time data recorded in the memory 110 is 120 bytes, and the size of data output from the memory 110 is 144 bytes.

If the amount of real-time data necessary for packetization is recorded in the memory 110, the memory controller 100 reads the real-time data of the amount (144 bytes) necessary for forward packetization from the memory 110 and transmits the data. While outputting to the generation unit 120, it outputs the recording position information (corresponding to the address information recorded in the memory 110) indicating the recording position of the real-time data to the transmission and reception controller 140. Then, the master transceiver controller 140 forwards the header information including the recording location information, real time data, and control information through the RF transceiver 150.

These forward packets are transmitted through the setup channel in the data transmission section and through the replacement channel in the channel test section. In the exemplary embodiment of the present invention, as shown in FIG. 5, eight frames constitute one super frame, and data transmission is performed through the set channel Fc in seven frames within the super frame, and a channel test is performed in one frame. Assume that it is done.

Hereinafter, referring to FIGS. 3 and 5, a process of testing a test replacement channel that is temporarily set and storing the test replacement channel as an actual replacement channel will be described in detail.

First, the master and slave side transceiver controller 140 sets a channel frequency for communication with each other (step 200). This is referred to as the setting channel (Fc) above.

When one set-up channel Fc is formed without interference, the master transceiver controller 140 forms a forward packet having a structure as shown in FIG. 2 and transmits real time data. The message is recorded and transmitted (step 210). The AM message is a kind of command for transmitting a backward packet through a current configuration channel (Fc). In response to receiving the forward packet including the AM message, the slave side transmit / receive controller 140 transmits the response packet (RM) message included in the control information to the master side (step 220).

Then, the master transceiver controller 140 accumulates the number of sync field error bits of the backward packet received through the configuration channel Fc (step 230). This is a method for checking the existence of channel interference. In some cases, it may be checked by the number of bit errors of real-time data or non-real-time data inserted into a received packet.

In operation 240, the master transceiver controller 140 accumulating the sync field error bits of the backward packet checks whether an alternate channel test period has arrived. In the embodiment of the present invention, it is assumed that the replacement channel test period arrives every super frame period, that is, every eighth frame, as shown in FIG. If the alternative channel test period has not arrived, the master side transmit / receive controller 140 transmits the forward packet including the AM message to the slave side through the current channel, that is, the set channel Fc, and responds to the slave side. A backward packet including an RM message is received and the number of sync field error bits is accumulated. According to the embodiment of the present invention, the master transceiver controller 140 accumulates the number of sync field error bits for backward packets of seven frames.

If the replacement channel test cycle arrives as a result of step 240, the master transceiver controller 140 transmits a forward packet including an AMTx message indicating the change to the test alternate channel to the slave side (step 250). Change the configuration channel to the test channel. The AMTx message includes test alternate channel information. For reference, the test replacement channel temporarily set in the replacement channel test period may be set to a frequency channel sufficiently spaced apart from the current set channel Fc. The reason for this is to avoid the interference since the probability of interference is high even in the frequency around the set channel (Fc) where the channel interference occurs. In FIG. 5, the test replacement channel is designated as F1.

On the other hand, the slave side transmit / receive controller 140 replaces the test for indicating the current set channel Fc in the received forward packet if the control information in the forward packet is an AMTx message requesting a change of the set channel (step 260). Change to the channel (step 270). The slave side transmit / receive controller 140 transmits a backward packet including an RM message through the corresponding test replacement channel (step 280).

Accordingly, the master transceiver controller 140 may receive a backward packet through the test replacement channel, and calculate the number of sync field error bits of the received backward packet (step 300) to determine the current test replacement channel. It may be determined whether it may be set as a good substitute channel (step 310). The determination method can be performed by comparing the accumulated average value of the sync field error bits in the super-frame alternate channel test interval with the sync field error bits in the super frame data transmission interval.

If the number of sync field error bits of the backward packet received through the test replacement channel F1 is the cumulative average value of the number of sync field error bits of the backward packet received through the setting channel Fc in the data transmission interval in the same super frame. If smaller, the test replacement channel F1 may determine that channel interference is weak.

In conclusion, the master transmitter / receiver controller 140 first sets one test replacement channel in a replacement channel test interval in a super frame periodically, and the number of sync field error bits of a backward packet received through the channel is first set. If the number of sync field error bits of the backward packet received in the data transmission section in the super frame is smaller than the accumulated average value, the test replacement channel is stored as an actual replacement channel. The controller continuously checks whether channel interference occurs in the stored actual replacement channel in each of the repeated superframe replacement channel test intervals through steps 210 to 310 described above. If there is continuous interference on the actual alternate channel, a new test alternate channel F2 is newly set (step 320) to check for channel interference, and if there is no error, the test alternate channel F2 is set as a new alternate channel. Set an alternate channel.

Hereinafter, a process of transmitting the real time data transmitted through the configuration channel Fc to the new channel through the replacement channel F1 or F2 due to continuous channel interference will be described with reference to FIGS. 4 and 6.

First, the real-time data, which is forward packetized and transmitted through the configuration channel Fc, is restored by the slave-side reception data processor 130 and stored in the memory 110 under the control of the slave-side memory controller 100. In this case, the stored location may be a memory address indicated by the recording location information (for example, A0) included in the received forward packet. When the storage of the real-time data is completed in the memory address indicated by the recording position information A0, the slave-side memory controller 100 indicates subsequent recording position indication information indicating a memory address where the real-time data of the subsequent forward packet should be stored. (For example, A1) is generated and output to the slave side transceiver controller 140. The subsequent write position indication information A1 is included in the backward packet and input to the master-side memory controller 100. For reference, the slave-side memory controller 100 controls the memory 110 so that the stored real-time data is output only when the amount of real-time data exceeding a preset threshold is filled in the memory 110, and the current memory In operation 110, output position indication information An of the real-time data being output is generated and output to the slave side transceiver controller 140. The output position indication information An can synchronize the real-time data output of slaves connected to the master at different times. That is, if real-time data is stored in the memory address indicated by the output location information in the forward packet, the slave-side memory controller 100 reads out the real-time data from the memory 100 and outputs the control.

According to the operation of the slave-side memory controller 100 described above, in the slave-side memory controller 100, subsequent recording position indication information and output position indication information are generated and input to the slave-side transmit / receive controller 140, and the slave-side transmit / receive. The controller 140 converts the inputted information and non-real-time data into a backward packet and transmits the received packet to the master.

Accordingly, the master side receives a backward packet including subsequent write position indication information and output position indication information, and the information is restored by the reception data processor 130 and input to the master memory controller 100.

The master memory controller 100 may check whether the retransmission request of the real-time data transmitted in the previous frame is requested from the restored information (operation 400). The inspection method is possible by comparing the recording position information of the real time data transmitted in the previous frame with the subsequent recording position indication information in the backward packet. For example, if the recording position information of the real-time data transmitted in the previous frame is A0 and the subsequent recording position indication information received through the backward packet is A0, it means that the real-time data was not transmitted normally due to channel interference.

In this way, if it is determined whether the data retransmission request is a retransmission request situation, the master-side memory controller 100 checks whether the retransmission request is continuous (step 410). If the result of the inspection is not a continuous interference situation, the memory controller 100 stores the amount of data currently stored in the memory 110, that is, the amount of memory (step 420), and retransmits the real-time data transmitted in the previous frame through the setting channel Fc. Give it.

In contrast, if it is determined that the continuous interference situation, the master-side memory controller 100 proceeds to step 430 to calculate the amount of data change stored in the memory. The amount of data change is the amount of memory memorized in step 420, that is, the amount of memory present at the time of the first retransmission request. When the amount of change in memory data during the real-time data retransmission period exceeds the channel change reference value (step 440), the master-side memory controller 100 determines not only the continuous interference of the set channel Fc but also prevents loss of real-time data. The request for change to the alternate channel tested in FIG. 3 is requested to the master transceiver controller 140 (step 450).

That is, when the data retransmission request is repeated, the master-side memory controller 100 checks whether the amount of change in memory data from the first retransmission request to the present satisfies the channel change condition, and if the condition is satisfied, does not perform further retransmission. The request is to change to the alternate channel that you tested.

When such a request is made, the master transmission / reception controller 140 transmits a forward packet including the AMCx message indicating the channel change as control information to the slave side, so that the master and the slave alternate the current configuration channel Fc without interference. The channel can be changed to (F1).

In addition, the master side reads and retransmits the previously retransmitted real-time data in the memory 110 so that the slave side may receive the real-time data that has been repeatedly retransmitted as well as a series of real-time data subsequent thereto.

Therefore, the present invention can obtain the effect that real-time data is not lost even if the change to the alternate channel by the continuous channel interference.

For reference, referring to FIG. 6, (a) and (b) illustrate the case of changing the setting channel from Fc to the alternate channel F1, respectively, all of which is because there is continuous channel interference in the setting channel Fc. . Reference numerals D and E indicate the time points of changing the frequency channel of the slave.

 As described above, the present invention repeats the transmission of the data generated by the transmission error while monitoring the change amount of the memory data buffered at the master side when the data transmission error occurs, but if the change amount of the buffered memory data exceeds the set reference value, the interference occurs. By changing to a new alternative channel that is not present and retransmitting data from the first transmission error, there is an advantage that the real-time data is not lost even if the channel is changed by continuous channel interference.

On the other hand, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only by the appended claims.

Claims (13)

In the master-side short-range wireless data transmission apparatus including a transmission data generation unit for adding redundancy to the data to be transmitted and output the data, and a reception data processing unit for restoring and outputting the data contained in the received backward packet to the original data, Stores the input real-time data in the memory and reads out the amount of real-time data necessary for packetization from the memory and outputs the real-time data to the transmission data generator, each time a real-time data retransmission request of a previous frame is received through a backward packet. A memory controller which checks the amount of change in the stored data and retransmits the real-time data of the previous frame or requests a channel change; Forward the real-time data output from the transmission data generation unit together with header information and transmit it through a setting channel, and find a channel without channel interference every alternate channel test period, store the channel as an alternate channel, and request a channel change of the memory controller. A transmission / reception controller for changing and controlling a current current setting channel to the replacement channel; And an RF transceiver for wirelessly interfacing the forward and backward packets with a slave side. The memory device of claim 1, wherein the memory controller comprises: a memory controller; And recording position information of the real-time data read out from the memory and output position information calculated from the output position indication information included in the backward packet to the transceiver controller as part of header information. The memory device of claim 2, wherein the memory controller comprises: a memory controller; If the recording position information of the real time data transmitted in the previous frame and the subsequent recording position indication information in the backward packet are the same, the real time data transmitted in the previous frame is retransmitted, and the amount of change of memory data during the retransmission period of the real time data is set to the channel change reference value. Short distance wireless data transmission device, characterized in that for changing the channel. The method of claim 1 or 3, wherein the transmission and reception controller; By comparing the cumulative average value of the sync field error bits of the backward packet received through the setup channel with the sync channel error bits of the backward packet received through the alternate channel in the alternate channel test interval during a predetermined interval. Short-range wireless data transmission, characterized in that the search for an alternate channel free of channel interference. In the slave-side short-range wireless data transmission apparatus including a transmission data generation unit for adding redundancy to the data to be transmitted and output the reception data processing unit for restoring and outputting the data contained in the received forward packet to the original data, Stores the real-time data restored by the receiving data processing unit in a memory address indicated by the recording location information in the forward packet, and the current recording memory and subsequent recording position indication information indicating a memory address where real-time data of the subsequent forward packet should be stored. A memory controller generating and outputting output position indication information of the real-time data being outputted from the memory controller; A transmission / reception controller configured to variably set a setting channel according to wirelessly received forward packet control information, and to perform subsequent packetization and transmission of subsequent recording position indication information and output position indication information input from the memory controller together with non-real-time data; And a RF transceiver configured to wirelessly interface the forward packet and the backward packet with a master side. The memory device of claim 5, wherein the memory controller comprises: a memory controller; And if the real time data is stored in a memory address indicated by the output location information in the received forward packet, the real time data is output from the memory. In the method for transmitting short-range wireless data, Storing real time data in memory for transmission; Reading the amount of real-time data necessary for packetization from the memory, forwarding the packet along with non-real-time data and header information, and transmitting the packet to a slave side through a set channel; Checking whether there is a data retransmission request in a backward packet transmitted from a slave side through the set channel; Comparing a data change amount stored in the memory with a preset channel change reference value when a data retransmission request is made; Requesting the slave to read the real-time data of the previous frame, which has been requested to be retransmitted, from the memory and retransmit to the slave according to the comparison result, or to change to the alternative channel found to be an interference-free channel in the alternative channel test period; And transmitting and receiving the forward packet and the backward packet through the replacement channel. The method of claim 7, wherein the forward packet, A sync field in which sync information is recorded; A control information field in which communication channel indication information is recorded; A header field in which recording position information for indicating a recording position of real-time data and output position information for indicating a data output position on a memory are recorded; And a field in which non-real-time data and real-time data are recorded, respectively. 8. The method of claim 7, wherein the backward packet is A sync field in which sync information is recorded; A control information field in which a response message is recorded; A header field in which subsequent recording position indication information indicating a memory address at which real time data should be stored, and output position indication information of the real time data currently output from the memory are recorded; And a field in which non-real-time data is recorded. 8. The system of claim 7, wherein the replacement channel comprises: a replacement channel; The test when the cumulative average value of the sync field error bits of the backward packet received through the setup channel for a predetermined period is larger than the sync field error bits of the backward packet received through the test replacement channel temporarily set in the alternate channel test interval. Short-range wireless data transmission method characterized in that it is set as an alternative channel. The method of claim 7, wherein the test substitute channel temporarily set in the substitute channel test period is set to one of frequency channels spaced apart by a predetermined distance from a current set channel frequency. In the method for transmitting short-range wireless data, Storing real-time data in the forward packet received through the setting channel in a memory address indicated by the recording location information transmitted together; Forwarding the recording position indication information in which subsequent real-time data in the forward packet to be stored and the output position indication information of the real-time data currently output from the memory together with non-real-time data to be transmitted to the master side; And transmitting a backward packet by varying a communication channel according to the received control information in a forward packet. The short-range wireless data transmission method of claim 12, further comprising reading out the real-time data from the memory and outputting the real-time data if the real-time data is stored in the memory address indicated by the output location information in the forward packet.

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