KR100910640B1 - Transmitting apparatus of packet data with high speed in hfc and method thereof - Google Patents

Abstract

An apparatus of transmitting packet data at a high speed in HFC and a method thereof are provided to improve the packet data transmission speed and distance in a wired mixed network by dividing one data stream into plural data streams and transmitting channels having different frequencies. A high frequency unit(1300) modulates a stream data signal into a high frequency signal having 2.4 GHz band and demodulates the high frequency signal into a stream data signal. A frequency converting unit(1400) divides the high frequency signal of 2.4 GHz band applied from the high frequency unit into the high frequency signals having over 900 MHz. In addition, the high frequency unit converts the high frequency signal of over 900 MHz band into high frequency signals of 2.4 GHz into stream data signals of low band and transmits the stream data signal of 2.4 GHz. A PLL(Phase Locked Loop) outputs the central frequency signal by connecting to the frequency converting.

Description

TRANSMITTING APPARATUS OF PACKET DATA WITH HIGH SPEED IN HFC AND METHOD THEREOF

The present invention is a high speed transmission of packet data signals in a hybrid fiber (HYBRID FIBER COAXIAL NETWORK (HFC) by optical and coaxial cable, in particular, by applying the MULTI INPUT MULTI OUTPUT (MIMO) technology to the data stream signal High speed packet data transmission device in a mixed network which improves transmission speed, transmission distance and signal quality by distributing to multiple channels having different frequencies, converting to 900 MHz band and transmitting the signal, and selecting the optimal stream signal at the receiver. It is about a method.

A mixed network is a wired communication network in which an optical cable (OPTICAL CABLE or OPTICAL FIBER) and a coaxial cable (COAXIAL CABLE) are mixed, and an optical cable is connected between a broadcasting station and an optical end station (or an optical network unit), and a coaxial cable is connected between the optical end station and the subscriber. Connect to send packet data at high speed.

With the development and expansion of related technologies in computers and Internet services, the use of the Internet in companies, schools, and government offices is very common, and the use of the Internet is becoming popular in each household.

The Internet is accessed through a server that provides various information or a network connected to computers around the world, and it searches and provides general technical information and technical information in all fields. It is provided in a media format of any one of a symbol, number, image, video, sound, or a plurality of media. Since each piece of information has a large amount of data, the packet is divided into a plurality of packets, and when the information is transmitted, a plurality of packet data are continuously transmitted. The flow of data continuously transmitted in this manner is called a stream. do. A packet includes data of a uniformly sized unit size, and a source and destination of information, a size of data, and the like are recorded, and the information can be delivered in real time to a plurality of computers connected to the Internet.

It is common to use coaxial cable as the network connection line of the Internet. The Internet has the characteristics that the more the number of computers connected at the same time, the greater the amount of data transmitted, the longer the transmission line, the lower the transmission speed and signal quality.

In particular, the use of information through the Internet is becoming active through the promotion of computers and the Internet, and the demand for high-speed packet data transmission is increased due to the development of application technologies such as Internet phone (IP-PHONE), digital cable broadcasting, and IP-TV. The demand is expanding to the field of low speed packet data transmission such as remote meter reading, crime prevention, disaster prevention and home automation. In other words, as the demand or demand for data transmission through the Internet continues to increase, it is necessary to develop a network that transmits a large amount of data at a higher speed, and a network composed of a transmission line suitable for such a demand needs to use an optical cable and a coaxial cable. Mixed network (HFC).

According to Data-over-Cable Service Interface Specifications (DOCSIS), an international technical standard that defines the standard specification of data transmitted through such a network, data transmission through a mixed network has a frequency of 5 to 860 MHz. Data is transmitted in the allowed bandwidth in the band, and bandwidth varies from country to country, but for example, 6 MHz is allocated in the United States and Korea and 8 MHz is allocated in Europe. Currently, data transmission through a mixed network uses a QAM modulation scheme, which is a quadrature amplitude modulation scheme.

As described above, there is a limit to the length of packet data transmission through the mixed network, and the longer the transmission length, the lower the signal quality.

Therefore, there is a need to develop a technique for increasing the packet data transmission length and improving the signal quality in a mixed network.

The present invention is to solve the problems and necessity of the prior art, and to distribute a single data stream to a plurality of data streams and to transmit the channel of different center frequency, the mixed network to increase the packet data transmission speed and transmission distance of the wired mixed network It is an object of the present invention to provide an apparatus and method for high-speed packet data transmission in.

In addition, since the present invention transmits packet data to a mixed network using MIMO technology, a frequency diversity scheme solves the problem of increased data error due to fading and poor signal transmission quality. It is an object of the present invention to provide a high speed packet data transmission apparatus and method.

In order to achieve the above object, the present invention inputs and outputs a multimedia stream data signal and controls operation of each functional unit to perform orthogonal amplitude modulation processing, application of IEEE 802.11 solution, and baseband stream data of 2.4 GHz band high frequency signal. Conversion, a control unit for distributing one stream data signal into one or more stream data, and monitoring to select and mix any one or more channel signals among one or more channel signals; A baseband part that applies a solution selected from 802.11n and IEEE 802.11g and adds an error correction function for checking encryption, decryption, and transmission error, and connects the baseband part to a 2.4 GHz band High frequency signal of 2.4 GHz band. A high frequency unit demodulating into a low-band stream data signal and a 2.4 GHz band high frequency signal applied from the high frequency unit are distributed to the same one or more 900 MHz band high frequency signals, and one or more 900 MHz band high frequency signals are selected. A frequency converter for converting into a 2.4 GHz band high frequency signal and applying it to the high frequency unit, a filter unit for connecting and removing the noise signal from the high frequency signal of the 900 MHz band, Matching unit for inputting / outputting high frequency signal of 900 MHz band to transmit / receive in impedance matching state, mixed network for transmitting 900 MHz band high frequency signal through coaxial cable and optical cable, and connecting to frequency matching unit PEL part which outputs center frequency signal, and one connected to PEL part and outputting To present a high rate packet data transmission apparatus in a mixed network consisting of Li comprising a PIA for adjusting the center frequency generated by the voltage on the control.

Preferably, the baseband portion is configured to be applied to the stream data signal transmitted by the control and monitoring of the controller and to release and recover the stream data signal which receives the added function.

In addition, the high frequency unit modulates the baseband stream data signal applied from the baseband unit into a 2.4 GHz band high frequency signal and supplies it to the frequency converter, and the 2.4 GHz band high frequency signal applied from the frequency converter is a baseband stream data signal. And demodulate it to supply to the baseband portion.

The frequency converter is configured to distribute one 2.4 GHz band data stream signal applied from the high frequency unit into one or more 900 MHz band data stream signals and supply the channel to the filter unit.

On the other hand, the frequency converter is configured to select any one or more of the one or more 900 MHz band data stream signal applied from the filter unit to convert the data stream signal of the 2.4 GHz band and apply it to the high frequency unit.

Here, the frequency converter is configured to convert a 2.4 GHz band high frequency signal applied from the high frequency unit into a 900 MHz band high frequency signal having at least one channel width of 40 MHz.

In addition, the frequency converter is configured to space each channel at 20 MHz intervals.

And the signal of each channel consists of the signal of the same content.

On the other hand, the frequency converter is configured to select the stream data signal of the channel having the largest received signal strength from the stream data signal of one or more channels under the control and monitoring of the control unit.

Here, the frequency converter is configured to select the stream data signal of the channel having the least transmission error among the stream data signals of the one or more channels under the control and monitoring of the controller.

In addition, the frequency converter selects and mixes a stream data signal of a channel having the largest received signal strength and a stream data signal of a channel having the least transmission error among the stream data signals of one or more channels under the control and monitoring of a controller, and then mixes one stream. It consists of a structure which converts into a data signal.

The PIC unit is configured to control and monitor the PEL unit to output one or more center frequencies of 40 MHz in the channel width and 20 MHz spaced apart from each other by the control of the controller.

On the other hand, the control unit is configured to control and monitor the PIC unit to control and monitor the PEL unit to output two center frequency signals.

The present invention devised to achieve the above object transmits high-speed packet data to a device including a control unit, a baseband unit, a high frequency unit, a frequency converting unit, a filter, a matching unit, a PEL unit, a PIC unit, and a mixed network. In the method, if the baseband multimedia stream data signal to be transmitted by the control unit is confirmed to be input to control the baseband portion orthogonal amplitude modulation, applying the IEEE 802.11 solution, the first to add encryption and forward error correction function And a second step of receiving the baseband stream data signal of the first step, modulating it into a 2.4 GHz band high frequency signal, converting the signal into a 900 MHz band high frequency signal distributed to one or more channels, and transmitting the signal to a mixed network in a noise canceling and matching state. If the process and the control unit determines that the 900 MHz band high frequency signal is received from the mixed network, And a third step of converting the stream data signal of at least one channel selected from among the stream data signals of the channel having the best reception signal strength and transmission error to a high frequency signal of 2.4 GHz band, and 2.4 of the third step. Receiving a GHz band high frequency signal and demodulating the baseband signal into quadrature amplitude demodulation, applying the IEEE 802.11 solution, decoding, and omitting error correction; Provides a high-speed packet data transmission method in a mixed network comprising a.

Preferably, the IEEE 802.11 solution is any one selected from IEEE 802.11n and IEEE 802.11g, and the channel of the 900 MHz band, the bandwidth is 40 MHz and the channel spacing is 20 MHz apart.

In addition, the stream of the optimal channel improves the signal-to-noise ratio and amplifies the level of the digital signal by mixing the signals of any one selected from the channel having the largest received signal strength and the channel having the least transmission error, or at least one selected stream. .

The present invention having the above-described configuration has an industrial use effect of transmitting a large data packet data stream at high speed and increasing a transmission distance through a mixed network composed of an optical cable and a coaxial cable. .

In addition, the present invention utilizes MIMO technology and transmits the same data stream to one mixed network through different frequency channels in a frequency diversity scheme, and selects an optimal stream on the receiving side. There is a convenient effect to increase the reliability of the transmission quality of the signal by reducing the error occurrence of.

The terms or words used in this specification and claims are not to be construed as limiting in their ordinary or dictionary meanings, and the principle that the inventor can appropriately define the concept of terms in order to explain his invention in the best possible way. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Many methods are used to increase the packet data transmission speed of wired and wireless networks. In wireless LAN, the concept of MULTI INPUT MULTI OUTPUT (MIMO) using multiple array antennas is introduced to increase the transmission speed. The basic concept of MIMO is that when a radio signal is transmitted, a signal identically copied in multipath is transmitted to each path by the repeated reflection and transmitted to the receiver. A system using one input and one output (SISO) can send and receive one stream into one space at a time, but the beauty concept can transmit multiple data streams simultaneously. That is, the beauty is a concept of inputting the same information in multiple channels and outputting the multiple channels in one wired transmission line. In general, the transmission line is bent in various shapes by the installation environment, and since the signal transmitted along the line is reflected several times by the bending of the transmission line, a large number of transmission paths are generated inside the line, causing fading. Fading becomes a very big problem in the transmission of digital signals, and diversity techniques have been introduced to solve the fading problem. Diversity includes spatial diversity, frequency diversity, and time diversity. Even in a wired transmission line, if the frequency is different, signals of multiple channels can be simultaneously transmitted using one line. The present invention applies a frequency diversity technique because a data stream is transmitted to a plurality of channels having different center frequencies through a single transmission line composed of a mixed network. The receiver receives received signal strength (RSSI) and transmission error (BER). The present invention relates to a technology for improving transmission speed, transmission distance, and transmission quality by selecting an optimal channel data stream through analysis.

1 is a functional block diagram illustrating a mixed network according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying Figure 1, the mixed network is a network consisting of an optical cable 200 and coaxial cable 400 is a broadband transmission network for transmitting a large amount of data to the subscriber home. That is, the TV broadcast data is transmitted from the data transmitting apparatus 100 to the data receiving apparatus 500 to which the coaxial cable 400 is connected via the optical cable 200 and the optical end station 300. The data transmission apparatus 100 is a device for converting and amplifying a high frequency signal and transmitting the optical signal to the optical cable 200 for cable TV broadcasting or cable TV broadcasting, and includes a data transmission apparatus (Headend) installed in a broadcasting station. The data transmitting apparatus 100 modulates and transmits data through an orthogonal frequency division (OFDM) scheme using subcarriers (carriers) of orthogonal amplitude modulation (QAM).

The optical cable 200 is a cable that converts electrical signals into optical signals and transmits them through glass fibers. The optical signal is transmitted without loss while repeating the reflection inside the optical cable. The bandwidth is wider than other wired transmission media, so the data transmission efficiency is good.

The optical end station 300 transmits a signal downward to the data receiving apparatus 500 and upwardly receives a signal from the data receiving apparatus 500. An optical cable 200 is connected between the optical end station 300 and the data transmitting apparatus 100, and a coaxial cable 400 is connected between the optical end station 300 and the data receiving apparatus 500.

The coaxial cable 400 forms a concentric circle between the outer conductor and the inner conductor and transmits a high frequency signal of several hundred MHz at a low frequency including a direct current.

The data receiving apparatus 500 includes a TV receiving apparatus installed in a subscriber's home, demodulates the received data and displays the data through a screen. When the data receiving apparatus 500 is an IPTV implemented as a bidirectional system, the data receiving apparatus 500 reversely transmits necessary data toward the data transmitting apparatus 100.

Meanwhile, according to an exemplary embodiment of the present invention, the data transmission apparatus 100 transmits data by extending from a conventional frequency band to a frequency region between 870 MHz and 1.6 GHz, and transmitting data in the following description of FIGS. 2 to 6. The device 100 will be described in detail. For simplicity, data transmission in the frequency range of 5 MHz to 860 MHz is omitted.

2 is a diagram illustrating a detailed functional configuration of a data transmission apparatus according to an embodiment of the present invention.

Hereinafter, referring to the accompanying drawings in detail, the data transmission apparatus 100 includes an input unit 110, a band expansion unit 120, an adaptive filter 125, a parallel and parallel converter 130, a modulator 140, and a transmitter ( 150).

The input unit 110 inputs cable TV broadcast, cable TV broadcast, various contents or programs in the form of data. The band extension unit 120 extends the frequency band of 5 MHz to 860 MHz used in the cable TV according to the DOCSIS standard to transmit the frequency band of 870 MHz to 1.6 GHz. That is, the band extension unit 120 transmits a larger amount of data by using relatively high frequency frequency resources, and transmits data stably since there is no frequency interference with the cable TV.

As a method for extending a frequency band, there are a method of applying an RF spectrum overlay technique using a phase locked loop (PLL) and a method of applying commercial MoCA silicon. However, in the present invention, commercial MoCA silicon is preferably applied.

Multimedia over Coaxial Alliance (MoCA) silicon is a method of transferring voice, video, and data using a large amount of unused bandwidth over in-home coaxial cable without new wiring or connectivity between devices. to be. In other words, the MoCA silicon method utilizes the existing coaxial cable infrastructure as a networking system to provide high quality of service (QoS) that transmits more data.

The adaptive filter 125 distributes the extended 870 MHz to 1.6 GHz frequency band signal through a plurality of channels (in the present invention, divided into eight channels). Here, the adaptive filter 125 maintains the frequency bandwidth of each channel at about 50 MHz and minimizes the frequency interval between the channels.

In general, due to the nature of the QAM method, the number of bits that can be transmitted is determined by a waveform SYMBOL. The lower the bit error rate (BER), the greater the number of bits that can be transmitted per symbol. Accordingly, the adaptive filter 125 maintains a signal to noise ratio (SNR) of 3.8 or more, minimizes interference between channels, and has a low bit error rate at high band frequencies. Adaptive filter 125 according to an embodiment of the present invention may be configured as an active filter. In FIG. 2, the adaptive filter 125 is described as being connected to the band extension unit 120, but may be connected to the modulator 140.

The serial-to-parallel converter 130 distributes serial data into parallel data corresponding to eight channels CH1 to CH8. As shown in FIG. 2, the data signal passing through the serial-to-parallel converter 130 is a modulator corresponding to each channel, that is, the first modulator 141, the second modulator 142,. The seventh modulation unit 147 and the eighth modulation unit 148 are transmitted.

Meanwhile, in the process of converting serial data into parallel data by the serial / parallel converter 130, a transmission delay may occur in a specific channel due to a sudden change such as noise or gain. Therefore, the serial-to-parallel converter 130 reduces the transmission band of a specific channel through a channel switching algorithm and increases the transmission band of another channel having good characteristics such as noise and gain. Accordingly, it is possible to prevent transmission delay and data loss of a specific channel and to prevent degradation of transmission quality.

The modulator 140 may include eight modulators (the first modulator 141, the second modulator 142,..., The seventh modulator 147, and the eighth modulator) corresponding to the eight extended channels, respectively. (148)).

In the present invention, when transmitting data in the frequency band of 870 MHz to 1.6 GHz, a Quadrature Amplitude Modulation (QAM) scheme and an Orthogonal Frequency Division Multiplexing (OFDM) modulation scheme are fused together in a cable TV. Modulate the transmitted data.

That is, data is divided into eight channels by the OFDM scheme, and the subcarrier (carrier) signals corresponding to the respective channels are modulated by the QAM scheme and transmitted.

The OFDM scheme refers to a modulation scheme for multiplexing data into a plurality of orthogonal narrowband carriers. In an embodiment of the present invention, the OFDM symbol in the frequency band of 870 MHz to 1.6 GHz is composed of a sub-carrier used in QAM modulation. Therefore, the OFDM scheme of the present invention involves a subcarrier used for QAM modulation in the frequency band of 870 MHz to 1.6 GHz. Accordingly, the transmission rate of the OFDM sub-carrier in the frequency band of 870 MHz to 1.6 GHz is determined by the modulator 140 having the QAM scheme.

The QAM method is a method of classifying a digital signal into a predetermined size or quantity and modulating the carrier signal with changing a phase. QAM is a form of two-dimensional symbol modulation in which two PAM (Phase Amplitude Modulation) signals are orthogonally combined. The data to be transmitted is mapped into four quadrant signal spaces, two constellations, two-dimensional, each having a plurality of signal (pager) points representing possible transmission levels. Each constellation signal point is commonly referred to as a "symbol" and is defined by a unique binary code. QAM constellations use "I" and "Q" components to represent in-phase and quadrature components, respectively, where QAM data or symbols are represented by two I and Q components. Unlike the QPSK (Quadrature Phase Shift Keying) method, the QAM method uses not only the phase but also its size as a variable, so that a relatively large amount of digital data is simultaneously transmitted at high speed. On the other hand, in the frequency band of 5 MHz to 860 MHz, data is modulated by the QAM method conventionally.

The transmitter 150 includes a plurality of transmitters (the first transmitter 151, the second transmitter 152,..., The seventh transmitter 157, corresponding to the eight modulators 141, 142,..., 147, 148). Eighth transmitter 158). The transmitter 150 transmits a data signal corresponding to each frequency band through the mixed network HFC.

Hereinafter, a method of transmitting data by extending a frequency band from the data transmitting apparatus 100 to the data receiving apparatus 500 will be described with reference to FIGS. 3 to 5.

3 is a flowchart illustrating a data transmission method of a data transmission apparatus according to an embodiment of the present invention.

Various contents or programs are input in the form of voice or video data through a server of a broadcasting station (S310). The band extension unit 120 extends the frequency into the 870 MHz to 1.6 GHz band, which is a frequency band not used in the DOCSIS standard (S320). The adaptive filter 125 distributes the extended frequency band to eight channels CH1 to CH8 through filtering. Here, the adaptive filter 125 adjusts the bandwidth to minimize the interference between channels and minimize the gap between the channels.

4 is a diagram illustrating a frequency band in which a channel is added, according to an exemplary embodiment of the present invention, and FIG. 5 is an enlarged diagram illustrating a frequency band by one channel in FIG. 4.

According to FIG. 4, a wired communication signal such as a cable TV is mainly transmitted in a frequency band between 5 MHz and 860 MHz, and a wireless communication signal using PCS is transmitted in a frequency region of 1.7 GHz or more. According to an embodiment of the present invention, eight channels are allocated to a frequency band between 870 MHz and 1.6 GHz, and each channel has a bandwidth of 50 MHz. Therefore, it is possible to increase the transmission capacity by eight times than when adding one channel.

Referring to FIG. 5, one channel has a frequency band with a minimum frequency of Fc-28.5 MHz and a maximum frequency of Fc + 28.5 MHz with respect to a center frequency (Fc). The gain of the frequency is about 40 dB, the frequency bandwidth is about 50 MHz, and the data throughput per channel is 120 Mbps or more.

When the extended frequency band is separated into eight channels, the serial-to-parallel converter 130 converts serial data into eight parallel data corresponding to eight channels CH1 to CH8 (S340). Parallel data is allocated to each channel, and the allocated data is modulated by the modulator 140 (S350). Here, the data is modulated by an OFDM scheme involving a QAM modulated subcarrier, and the transmitter 150 transmits the modulated data to the data receiving apparatus 500 through the mixed network HFC (S360).

6 is a diagram illustrating a detailed configuration of a first modulator according to an embodiment of the present invention.

Hereinafter, a process of QAM modulation of data with reference to the accompanying drawings will be described in detail. The remaining seven modulation and demodulation units included in the modulator 140, that is, the second modulator 142,. Since the configurations of the seventh modulator 147 and the eighth modulator 148 are the same, only the first modulator 141 will be described.

The first modulator 141 includes the converter 170, the first level generator 171, the second level generator 172, the delay element 173, the carrier generator 174, the phase shifter 175, and the first A first mixer 176, a second mixer 177, and a summer 178.

The converter 170 converts binary data input from the serial / parallel conversion unit 130 into binary parallel data, and converts the data into I-channel data and imaginary-side data, which are real data. Separate into Q channel (Quadrature-phase) data.

The first level generator 171 and the second level generator 172 generate and adjust the levels of signals separated into I and Q channel data, respectively, in the converter 170.

The delay element 173 delays the Q channel signal to simultaneously modulate the I channel signal and the Q channel signal that have passed through the first level generator 171 and the second level generator 172.

The carrier generator 174 mixes the carrier with the I-channel signal, and the phase shifter 175 shifts the phase of the carrier generated by the carrier generator 174 by 90 °.

The first mixer 176 mixes the signal output from the first level generator 171 with the carrier generated from the carrier generator 174. The second mixer 177 mixes the Q channel signal output from the delay element 173 and the carrier shifted by 90 ° from the phase shifter 175.

The summer 178 sums the I channel signals and the Q channel signals output from the first mixer 176 and the second mixer 177.

The operation of the first modulator 141 configured as described above will be described in detail.

When binary data consisting of 0 or 1 is input, the converter 170 converts the binary data into parallel data of NRZ (Non Return to Zero) format. The parallel data is divided into I and Q channels, and the I and Q channel signals are simultaneously modulated by the delay element 173. The delay element 173 delays the Q channel signal so that the I channel and the Q channel signal having the phase difference are modulated at the same time. The carrier is mixed with the I channel signal, and the phase of the carrier is shifted by 90 ° to be mixed with the delayed Q channel signal. The I-channel signal and the Q-channel signal are added through the summer 178. Since the I-channel signal and the Q-channel signal are orthogonal to each other, the interference does not occur even when synthesized through the summer 178.

7 is a diagram illustrating a detailed functional configuration of a data receiving apparatus according to an embodiment of the present invention, and FIG. 8 is a flowchart of a data output method of the data receiving apparatus according to an embodiment of the present invention.

Hereinafter, the data receiving apparatus 500 will be described in detail with reference to FIGS. 7 and 8, and the data receiving apparatus 500 includes a communication unit 510, a demodulator 520, a serial-to-parallel converter 530, and an output unit ( 540). The communication unit 510 includes eight receiving units (a first receiving unit 511, a second receiving unit 512,..., A seventh receiving unit 517, and an eighth receiving unit 518) configured in parallel. Each receiver receives data transmitted from the data transmission apparatus 100 through the mixed network HFC (S810).

The demodulator 520 includes eight demodulators (first demodulator 521, second demodulator 522, ..., seventh demodulator 527, and eighth demodulators) corresponding to the eight extended channels, respectively. 528). Each demodulator demodulates data received from the receiver 510 (S820). In the demodulation method, similar to the modulation method described with reference to FIG. 6, data is divided into I channel data and Q channel data to adjust phase and amplitude.

The serial-to-parallel converter 530 merges parallel data corresponding to eight channels CH1 to CH8 and converts the parallel data into serial data (S830). The output unit 540 outputs serial analog data to the screen (S840).

The present invention extends the 5 MHz to 860 MHz frequency band used in the cable TV and transmits data in the 870 MHz to 1.6 GHz frequency band, thereby effectively utilizing the frequency band and transmitting a large amount of data.

9 is a functional configuration diagram of a high speed packet data transmission apparatus in a mixed network according to an example of the present invention.

Hereinafter, with reference to FIG. 9, the first terminal unit 1000, the mixed network 2000, and the second terminal unit 1000 ′ are configured.

The first terminal unit 1000 and the second terminal unit 1000 ′ have the same configuration and function, and any one selected is operated as a head-end and the other is operated as a user-end. Since the mutual signal is transmitted or received, the following description will be given based on the first terminal unit 1000 in order to avoid duplication.

The first terminal unit 1000 may include a control unit 1100, a baseband unit 1200, a high frequency unit 1300, a frequency converter 1400, a filter unit 1500, a matching unit 1600, and a PEL unit 1700. , PIC unit 1800 and the mixing network (2000).

The control unit (CPU) 1100 controls and monitors the entire operation, inputs and outputs a multimedia stream data signal, the baseband unit 1200, the high frequency unit 1300, the frequency converter 1400, the filter unit 1500, The matching unit 1600 is connected to the matching unit 1600, the PEL unit 1700, and the PIC unit 1800. In addition, by the MAC operating system, the baseband signal is processed by quadrature amplitude modulation (QUADRATURE AMPLITUDE MODULATION: QAM), the IEEE 802.11 solution is applied, the 2.4 GHz band high frequency signal is converted and canceled ( Inverse transformation), which distributes and transmits one 2.4 GHz band stream data signal to one or more, and controls and monitors to select and transmit an optimal signal among one or more received signals.

Orthogonal Amplitude Modulation method loads a signal by mutually converting amplitude (AMPLITUDE) and phase (PHASE) of carrier wave. It is a digital modulation method that combines the data, and does not require a pilot signal indicating the timing of data, and can transmit data at high speed within a limited transmission band.

The baseband unit (MAC / BB) 1200 processes the data signals transmitted and received in the baseband (BB) by the MAC (OS) operating system (OS), the control and monitoring of the control unit 1100 Apply one of the solutions selected from the IEEE 802.11n and IEEE802.11g protocols that define the standard of the wireless LAN, or release (recover) the application of the solution, and the third party unfairly eavesdrops. For security to prevent from doing so, it adds forwarding error correction (FORWARD ERROR CORRECTION: FEC) function to encrypt and decrypt in selected way and check transmission error.

Omni-directional error correction (FEC) is a technique for transmitting and adding additional information (REDUNDANCY) to the packet data transmitted by the transmitting side, so that the receiving side detects and corrects the error with the additional information.

The high frequency unit (RF) 1300 modulates, from the baseband unit 1200, a baseband (BB) signal to which the IEEE 802.11 series solution of the WLAN standard is applied, into a high frequency signal of a 2.4 GHz band, which is a radio frequency band allocated to the WLAN. MODULATION is applied to the frequency converter 1400. In addition, the high-frequency signal of the 2.4 GHz band received from the frequency converter 1400 according to the wireless LAN standard is demodulated (DEMODULATION) of the signal of the baseband (BB). That is, the high frequency unit 1300 is a bidirectional structure in which a transmission / reception (TRX) function unit is integrally provided.

The frequency converter 1400 converts a 2.4 GHz band high frequency stream data signal applied from the high frequency unit 1300 into a 900 MHz band high frequency signal by one or more channels under the control of the controller 1100 (CONVERT). And at least one of the 900 MHz band high frequency signals applied to the filter unit 1500 by one or more channels from the filter unit 1500 and converting them into a high frequency signal of the 2.4 GHz band. 1300).

In this case, when one stream data signal is divided into one or more multiple stream data signals, the content of the data and the signal level are the same and the center frequency Fc is allocated differently. That is, stream data having the same content is transmitted at different frequencies. The center frequency of the frequency converter 1400 is adjusted by a center frequency (Fc) or an intermediate frequency (INTERMEDIATE FREQUENCY: IF) signal applied from the PEL unit 1700, and the PEL unit 1700 is the PIC unit 1800. Generates and outputs the specified center frequency or intermediate frequency under the control of.

In addition, the frequency converter 1400 analyzes a plurality of stream data applied from the filter unit 1500 to one or more to receive the best received signal strength (RSSI) or the lowest BIT ERROR RATE (BER). Choose the best one from the list. On the other hand, the best received signal strength (RSSI) and the smallest transmission error (BER) are selected and synthesized or combined to improve the signal-to-noise ratio (S / N) and amplify the digital signal level. can do.

Synthesis of stream data signal combines the signal of the channel with the highest received signal strength and the channel with the lowest transmission error and selects it as one channel, or selects the channel with the largest received signal strength and the next largest channel. There may be a mixing method, a channel having the least transmission error, a method of mixing the signals of the channel having the least order in the following order, and various application methods may be selected. That is, the optimal stream is selected in the manner selected by the control and monitoring of the controller.

The frequency converter 1400 is provided with one or more in the same configuration and the channel frequency of 900 MHz is different by the center frequency or the intermediate frequency signal applied from the PEL unit 1700. In FIG. 9, three frequency converters 1400 are illustrated, but they may be provided more or less, and have an optimal number in consideration of the cost and size of the device. It is desirable to have a channel.

At this time, each frequency converter 1400 becomes one channel and transmits a stream data signal in a 40 MHz band. In addition, each frequency converter 1400 is spaced at a channel interval of 20 MHz, respectively, under the control and monitoring of the controller 1100. In other words, if the channel is adjacent to each other in calculation, the intermediate frequency of each channel should be 60 MHz isolated or separated. The reason for such channel spacing is to prevent crosstalk or interference and interference of the signals of each channel.

As such, since the plurality of frequency converters 1400 are provided, frequency diversity technology can be used. That is, in the present invention, since the frequency diversity technique is applied in the mixed network 2000, fading can be prevented and the channel signal having the best reception signal strength (RSSI) and the channel error (BER) can be selectively used. have.

10 is a conceptual explanatory diagram for converting a high frequency signal of the 2.4 GHz band into one or more channel signals of the 900 MHz band according to the present invention and transmitting.

Hereinafter, with reference to the accompanying drawings, a state in which the stream data signal of the 2.4 GHz band is converted into three channels at 900 MHz band of the center frequency f0, f1, f2 and transmitted simultaneously conceptually. At this time, three channels in the 900 MHz band where the center frequencies are f0, f1, and f2 are data signals having the same contents and only different frequencies. That is, since signals of different channels have different frequencies, they can be simultaneously transmitted through one transmission path. Since the signal of each channel has a difference in transmission characteristics according to frequency, it is transmitted with different received signal strength and transmission error at the receiving side according to the environmental conditions of the mixed network 2000 used as the transmission path. When selecting or mixing the signal of the optimal channel, it is possible to improve the transmission distance and the signal transmission characteristics.

On the other hand, the frequency converter 1400 in FIG. 9 is a reference for selecting any one of the optimal channel among the plurality of channels received by the control of the control unit 1100 of the received signal strength (RECEIVE SIGNAL STRENGTH INDICATOR: RSSI) Select the 900 MHz channel with the largest value, or select the 900 MHz channel with the lowest BIT ERROR RATE, or the signal of the channel with the highest received signal strength and the channel with the lowest transmission error. Is synthesized or mixed to select one channel signal. On the other hand, the mixing method may include a method of mixing the channel having the largest value of the received signal strength and a signal of the larger channel in the following order, a method of mixing the signal of the channel having the least transmission error and the channel having the smallest transmission error in the next order, and the like. In addition, various application methods may be selected. It will be described in detail in the description of FIG. 11 attached as an example.

FIG. 11 is a conceptual explanatory diagram for selecting an optimal one from one or more 900 MHz band high frequency signals and converting the same into a high frequency signal of 2.4 GHz band according to the present invention.

Hereinafter, a detailed description will be made with reference to the accompanying drawings. Among the one or more 900 MHz band high frequency signals having different center frequencies, such as f0, f1, and f2, the received signal strength and transmission error are compared to select and transmit stream data of an optimal channel. . In other words, when transmitting and receiving stream data signals having the same contents at two center frequencies, it may be referred to as 2 * 2 beauty (MIMO), and when transmitting and receiving at three center frequencies, it may be referred to as 3 * 3 beauty. have.

On the other hand, the filter unit 1500 in Figure 9 is removed by removing the low or high frequency signals other than 900 MHz band high frequency signal from the stream data signal transmitted or received in each channel or bidirectional harmonics (HARMONIC) component and Remove the noise signal from the outside.

The matching unit 1600 inputs or outputs a high frequency stream data signal for each channel of the 900 MHz band in an impedance matching state and transmits the optimal condition suitable for the mixed network 2000. Each of the above functional parts is bidirectional.

The PIEL unit 1700 is a phase locked loop (PLL), and is capable of adjusting a frequency output by voltage control. The frequency converter 1400 is an example of each channel by f0, f1, and f2. Outputs the center frequency (Fc) or the intermediate frequency (IF) to operate at the center frequency.

The PIC unit 1800 adjusts or adjusts the center frequency or the intermediate frequency output by the PEL unit 1700 since the voltage control is performed by the PEL unit 1700 under the control and monitoring of the control unit 1100. In this case, the PIC unit 1800 is controlled and monitored by the controller 1100. PIC is short for PLL CONTROL IC.

The mixed network 2000 is a network consisting of a mixture of an optical cable and a coaxial cable, and an optical cable can transmit high-frequency and wide-band data at high speeds in a long distance at a high speed. Sections are affected by the transmission bandwidth, speed and distance of the coaxial cable.

In general, all networks use a plurality of distributors for distributing, and due to such attenuation or loss, a large amount of fading and transmission are generated. Limited.

Even in the mixed network 2000, such a divider transmits a high frequency signal of 900 MHz band, which is not suitable for transmitting a high frequency signal of 2.4 GHz band.

In addition, the frequency diversity technique according to the present invention is applied to reduce fading occurring in a mixed network.

12 is a flowchart illustrating a method of transmitting high-speed packet data in a mixed network according to an example of the present invention.

Hereinafter, with reference to the accompanying drawings, when it is confirmed by the control unit 1100 that the data signal to be transmitted in the baseband (BB) is input (S2000), orthogonal amplitude modulation of the input baseband data signal (QAM) scheme, and the baseband portion 1200 is applied to any one of the solutions selected by the IEEE 802.11n or IEEE 802.11g protocol, which is the world standard technical standard of the wireless LAN, and designated to not be eavesdropped Control and monitor to perform additional processing to the CRC function to encrypt and check the error of the digital data (S2100).

In addition, the controller modulates the digital stream data signal of which baseband processing is completed through the high frequency unit 1300 to a 2.4 GHz band high frequency signal which is a frequency allocated to the WLAN (S2200), and converts a stream data signal of the 2.4 GHz band into one. In this case, the contents of the distributed data are the same, and are converted through the frequency converter 1400 into a 900 MHz band high frequency signal having a 40 MHz bandwidth and a channel interval of 20 MHz (S2300). The conversion to the signal of the 900 MHz band is to transmit through the mixed network (2000).

As such, the stream data signal converted into the 900 MHz band high frequency by one or more multiples removes a noise signal (NOISE SIGNAL) including unnecessary frequencies and harmonics through the filter unit 1500 and minimizes the noise in the mixed network 2000. Matching is performed through the matching unit 1600 to be normally transmitted by the loss, and then transmitted to the mixed network (S2400).

In addition, when it is confirmed that the 900 MHz band high frequency signal is received from the mixed network through monitoring of each functional unit (S2500), the control unit 1100 receives and inputs a matching state through the matching unit 1600, and the filter unit 1500. By removing the unnecessary signal noise through (S2600).

On the other hand, by controlling and monitoring the frequency converter 1400 to analyze the signal of each channel received and input to one or more channels, any one selected to have the best received signal strength (RSSI) or low error (BER) The channel signal or any one or more selected channel signals are mixed to improve the signal-to-noise ratio (S / N) and convert the digital stream data signal having a higher level into a high frequency signal of 2.4 GHz band (S2700).

The high frequency signal of the 2.4 GHz band is demodulated by the high frequency unit 1300, which is converted into a baseband signal which is easily processed by the digital signal (S2800).

The signal converted to the baseband is decoded by the baseband unit 1200, omnidirectional error correction processing for detecting and correcting transmission errors, and at the same time, the IEEE 802.11 solution, which is a wireless LAN protocol, is applied and orthogonal to the control unit. The demodulated by the amplitude modulation method (S2900), and the demodulated digital data signal is output for application (S3000).

In the case of transmitting a high frequency signal in the 2.4 GHz band in the mixed network 2000, it is theoretically possible to transmit 100 meters, which is -10 dBm, but experiments confirm that the transmission is about 30-40 meters. The reason is that the frequency characteristics of each accessory including the splitter are set to 1 GHz.

According to the configuration of the present invention, when the IEEE 802.11g solution is applied, the transmission distance in the mixed network is improved to transmit about 500 meters by -50 dBm with the same signal strength and no error. When the IEEE 802.11n solution is applied, it has been improved to transmit about 650 meters of -65 dBm. Here, 1 dBm is a transmission distance of about 10 meters in the case of 5C cable.

In general, the equation for calculating the loss in the transmission path according to the frequency is as follows.

[Equation]

PATH LOSS = 20 log ((4 * phi * d) / lamda)

In other words, if the frequency of the signal is high, the wavelength is shortened, so the transmission loss (LOSS) becomes large, so that the transmission distance in the transmission path is shortened.

Therefore, by applying the frequency diversity technology, the same signal is converted into a channel signal by a plurality of frequencies having different reference frequencies and transmitted simultaneously, and the received signal strength (RSSI) is the best by analyzing the signal of each channel at the receiving side. Selecting a channel with less transmission error (BER) improves transmission distance, transmission speed, and fading, and also improves signal-to-noise (S / N) ratio by combining the optimal two channel signals.

Although the present invention has been described in detail only with respect to the described embodiments, it is obvious to those skilled in the art that various modifications and changes are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims. .

1 is a functional block diagram illustrating a mixed network according to an embodiment of the present invention;

2 is a diagram showing a detailed functional configuration of a data transmission apparatus according to an embodiment of the present invention;

3 is a flowchart illustrating a data transmission method of a data transmission apparatus according to an embodiment of the present invention;

4 is a diagram illustrating a frequency band in which a channel is added according to an embodiment of the present invention;

5 is an enlarged diagram illustrating a frequency band of one channel in FIG. 4;

6 is a diagram showing the detailed configuration of a first modulator according to an embodiment of the present invention;

7 is a detailed functional configuration diagram of a data receiving apparatus according to an embodiment of the present invention;

8 is a flowchart illustrating a data output method of a data receiving apparatus according to an embodiment of the present invention;

9 is a functional configuration diagram of a high speed packet data transmission apparatus in a mixed network according to an example of the present invention;

10 is a conceptual explanatory diagram of converting a high-frequency signal of the 2.4 GHz band into one or more channel signals of the 900 MHz band according to the present invention,

FIG. 11 is a conceptual explanatory diagram for selecting an optimal one from one or more 900 MHz band high frequency signals according to the present invention, converting the same into a high frequency signal of 2.4 GHz band, and transmitting the same;

And

12 is a flowchart illustrating a method of transmitting high-speed packet data in a mixed network according to an example of the present invention.

          ** Explanation of symbols on the main parts of the drawing **

1000, 1000 ': terminal part 1100, 1100': control part

1200, 1200 ': Baseband part 1300, 1300': High frequency part

1400, 1400 ': frequency converter 1500, 1500': filter part

1600, 1600 ': matching part 1700, 1700': Pielbu

1800, 1800 ’: PIC Part 2000: Mixed Network

Claims (16)

Input / output of multimedia stream data signal and control operation of each functional unit to orthogonal amplitude modulation processing, application of IEEE 802.11 solution, conversion of baseband stream data to 2.4 GHz band high frequency signal, distribution of one stream data signal to one or more stream data And a controller for selecting and mixing any one or more channel signals from the one or more channel signals; A baseband accessing the control unit and applying a one-way solution selected from IEEE 802.11n and IEEE 802.11g to stream data in the baseband and adding an omnidirectional error correction function to check encryption, decryption, and transmission error; part; A high frequency unit connected to the baseband unit and modulating a stream data signal into a high frequency signal of a 2.4 GHz band, and demodulating the high frequency signal of a 2.4 GHz band into a baseband stream data signal; Distributing one 2.4 GHz band high frequency signal applied from the high frequency unit into one or more of the same 900 MHz band high frequency signal, wherein one or more 900 MHz band high frequency signals are selected and converted into a 2.4 GHz band high frequency signal. A frequency converter applied to the; A filter unit which connects to the frequency converter and cuts and removes a noise signal from a high frequency signal of a 900 MHz band transmitted and received; A matching unit which connects to the filter unit and inputs and outputs a high frequency signal of 900 MHz band in impedance matching state; A mixed network connected to the matching unit and transmitting a 900 MHz band high frequency signal through a coaxial cable and an optical cable; A PEL unit connected to the frequency converter and outputting one or more center frequency signals; And A PIC unit connected to the PEL unit and controlling the output of one or more center frequencies by voltage control; High speed packet data transmission apparatus in a mixed network comprising a. The method of claim 1, wherein the baseband portion, And a stream data signal applied to the stream data signal transmitted by the control and monitoring of the control unit, and configured to release and recover the stream data signal receiving the added function. The method of claim 1, wherein the high frequency unit, The baseband stream data signal applied from the baseband unit is modulated into a 2.4 GHz band high frequency signal and supplied to the frequency converter, and the 2.4 GHz band high frequency signal applied from the frequency converter is converted into a baseband stream data signal. A high speed packet data transmission device in a mixed network, characterized in that for demodulation and supply to the baseband portion. The method of claim 3, wherein the frequency converter, And a 2.4 GHz band data stream signal applied from the high frequency part to be distributed to one or more 900 MHz band data stream signals and supplied to the filter part for each channel. The method of claim 4, wherein the frequency converter, A high speed packet in a mixed network comprising at least one of at least one 900 MHz band data stream signal applied from the filter unit and converting the signal into a 2.4 GHz band data stream signal and applying the same to the high frequency unit. Data transmission device. The method of claim 4, wherein the frequency converter, And a 2.4 GHz band high frequency signal applied from the high frequency unit to a 900 MHz band high frequency signal having at least one channel width of 40 MHz. The method of claim 6, wherein the frequency converter, High speed packet data transmission apparatus in a mixed network, characterized in that each channel is spaced apart by 20 MHz intervals. The method of claim 7, wherein High speed packet data transmission apparatus in a mixed network, characterized in that the signal of each channel is composed of the same signal. The method of claim 5, wherein the frequency converter, And a stream data signal of a channel having the largest received signal strength among stream data signals of at least one channel under control and monitoring of the control unit. The method of claim 9, wherein the frequency converter, And a stream data signal of a channel having the least transmission error among stream data signals of one or more channels under control and monitoring of the controller. The method of claim 10, wherein the frequency converter, Under the control and monitoring of the control unit, a stream data signal of a channel having the largest received signal strength and a stream data signal of a channel having the least transmission error among the stream data signals of one or more channels are selected, mixed, and converted into one stream data signal. A high speed packet data transmission apparatus in a mixed network, characterized in that the configuration. The method of claim 1, wherein the PIC unit, In the mixed network, the control unit is configured to control and monitor the PEL part to output at least one center frequency 40 MHz in the channel width and 20 MHz spaced apart at the channel interval to the frequency converter. High speed packet data transmission device. The method of claim 12, wherein the control unit, And controlling and monitoring the PIC unit to control and monitor the PEL unit to output two center frequency signals. In the method for transmitting high-speed packet data to a device including a control unit, a baseband unit, a high frequency unit, a frequency converter, a filter, a matching unit, a PEL unit, a PCI unit, and a mixed network, A first step of controlling the baseband by modulating the baseband by applying a baseband multimedia stream data signal to be transmitted by the controller, applying an IEEE 802.11 solution, and adding encryption and omnidirectional error correction; A second step of receiving the baseband stream data signal of the first step, modulating the 2.4 GHz band high frequency signal, converting the signal into a 900 MHz band high frequency signal distributed to one or more channels, and transmitting the signal to a mixed network in a noise canceling and matching state; And If it is determined by the control unit that a 900 MHz band high frequency signal is received from the mixed network, it enters into a matched state, removes noise, and streams data of any one or more channels selected from among stream data signals of channels with optimal reception signal strength and transmission error. A third step of converting the signal into a high frequency signal in a 2.4 GHz band; A fourth step of receiving the 2.4 GHz high frequency signal of the third step, demodulating the baseband signal, applying an orthogonal amplitude demodulation, an IEEE 802.11 solution, decoding, and forward error correction; High speed packet data transmission method in a mixed network comprising a. The method of claim 14, The IEEE 802.11 solution is any one selected from IEEE 802.11n and IEEE 802.11g, The channel of the 900 MHz band, the bandwidth is 40 MHz and the channel interval is 20 MHz spaced apart, characterized in that the high-speed packet data transmission method in a mixed network. The method of claim 14, The optimal channel stream is one selected from a channel having the largest received signal strength and a channel having the least transmission error, or by mixing signals of the selected one or more streams to improve the signal-to-noise ratio and amplify the level of the digital signal. High speed packet data transmission method in a mixed network, characterized in that.

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