KR100723878B1 - An optical transmission apparatus and optical access network for wavelength-division mulplexing optical network with both sub-carrier multiplxe and sub-carrier multiple access schemes - Google Patents

Abstract

The present invention relates to an optical transmission apparatus and an optical subscriber network that use a combination of subcarrier multiplexing and subcarrier multiple access in an optical subscriber network of a wavelength division multiplexing scheme, and use a subcarrier multiple access (SCMA) scheme in an optical subscriber network. In order to remove the optical beat interference (OBI) caused by the optical fiber, the optical signal of each optical subscriber is received by several optical receivers in the main distribution frame (MDF) and converted into an electrical signal. An optical transmission device and an optical subscriber network using a combination of subcarrier multiplexing and subcarrier multiple access schemes that combine electrical signals and transmit a single optical signal.

The optical transmission device and optical subscriber network using the subcarrier multiplexing and the subcarrier multiple access scheme according to the present invention do not generate OBI at the optical line terminal (OLT) in a central office (CO). It can more effectively improve the signal-to-noise ratio, thereby increasing the number of optical subscribers, and reducing the construction cost per optical subscriber due to the increased number of optical subscribers.

Optical subscriber network, wavelength division multiple, subcarrier multiple, subcarrier multiple access, optical interference

Description

An optical transmission Apparatus and optical access network for Wavelength-Division Mulplexing optical network with both Sub-Carrier Multiplxe and Sub-Carrier Multiple Access schemes}

1 is a view illustrating an embodiment of a transmission method and a structure of an optical subscriber network using a wavelength division multiplexing method using a sub-carrier-multiplexing and a sub-carrier-multiple access method. Figure showing.

2 is a view illustrating another embodiment of a transmission method and a structure of an optical subscriber network using a wavelength division multiplexing method using a sub-carrier-multiplexing and a sub-carrier-multiple access method according to the present invention; Figure showing.

FIG. 3 is a diagram illustrating an embodiment of an optical subscriber network transmission method using a subcarrier multiplexing method and a subcarrier multiple access method in addition to the wavelength division multiplex method shown in FIG. 1 and an entire network including a central base station in a network having the structure thereof.

FIG. 4 is a diagram illustrating another embodiment of an optical subscriber network transmission method using a subcarrier multiplexing method and a subcarrier multiple access method in addition to the wavelength division multiplex method shown in FIG. 1 and an entire network including a central base station in a network having the structure.

* Explanation of symbols for the main parts of the drawings

100: optical subscriber 101: subscriber / demodulation unit

102: subcarrier signal transmitter in subscriber

103: subcarrier signal receiver in subscriber

104: wavelength C band optical transmitter in subscriber 105: optical receiver in subscriber

106: wavelength C / A band optical filter in the subscriber

111: wavelength C / A band optical filter in local base station

112: Wavelength C band optical receiver in local base station

113: Wavelength B band optical transmitter in local base station

114: wavelength A band optical splitter in local base station

115: wavelength B / A band optical filter in local base station

116: wavelength B / A band optical multiplexer / demultiplexer in local base station

The present invention relates to a wavelength-division-multiplexing optical subscriber network, and more particularly to sub-carrier-multiplexing and sub-carrier-multiple access. The present invention relates to an optical transmission device and an optical subscriber network using a combination of the following methods.

As a method for providing data service to subscribers using existing telephone lines, xDSL technology has been developed and used to this day. In addition, a data service plan using a cable network using coaxial cable has been proposed.

These existing data service technologies will not be a big problem considering the current volume of Internet traffic used by subscribers, but will be provided in the future, such as home office, tele-video conferencing, HDTV-class video services, tele-education, and telemedicine. It is expected that it is difficult to provide sufficient broadband high quality service because the expected ultra high speed service is generalized to general subscribers, because it has a band or distance limitation.

As a technology that is emerging as a subscriber access method for providing broadband services required by a user, there is an optical subscriber network technology. A network being studied recently is a wavelength division multiplex optical subscriber network.

The wavelength division multiplex optical subscriber network, which is attracting attention as the next generation subscriber network for the information age, has the advantage of providing not only a large amount of information to each subscriber but also excellent security.

However, the wavelength division multiplex optical subscriber network has a problem in that the construction and maintenance cost are high.

Given the characteristics of a typical subscriber network that requires a relatively low transmission rate and a large number of channels, unlike a general back-bone network having a high transmission rate on a small channel, in order to solve the cost problem, There is a need for a new network that can accommodate as many subscribers as possible with less communication resources, ie maximize the number of subscribers per fiber.

Thus, subcarrier multiplexing and subcarrier multiple access schemes can be remultiplexed into time-division multiplexing and time-division multiple access schemes for each wavelength optical channel of a wavelength division multiplex optical subscriber network, or can be multi-divided into multiple subcarriers to process more subscribers. Subscriber networks are considered an alternative.

The advantages and disadvantages of the time division multiplexing and time division multiple access schemes and the subcarrier multiplexing and subcarrier multiple access schemes are described in detail below.

The time division multiplexing and time division multiple access schemes have the advantage of enabling efficient multiplexing of data of multiple subscribers.

However, the implementation requires accurate synchronization, not only the connection of another subscriber is affected by the status or needs of other subscribers, but the increase in overhead caused by periodic polling or ranging is pointed out as a disadvantage. have.

On the other hand, subcarrier multiplexing and subcarrier multiple access method allocates different subcarriers to each subscriber sharing the optical fiber, loads information on the subcarriers assigned to the subscriber, and the receiver uses a subcarrier bandpass filter corresponding to the subscriber. It filters out subscriber's information.

Although it does not have the disadvantages of time division multiplexing and accurate synchronization of time division multiple access schemes, effects of different subscriber states or demands, and increased overhead due to periodic polling or ranging, optical subscription using subcarrier multiple access schemes. In case of magnetic network, if Optical Beat Interference (OBI), which occurs when two or more light sources are simultaneously received at the optical receiver of the central base station, acts as a large factor to lower the signal-to-noise ratio It has a disadvantage.

The present invention has been proposed to solve the above problems, and the subcarrier multiplexing method and the subcarrier multiple access method are mixed with the wavelength division multiplexing method. In the case of the subcarrier multiple access method, the OBI does not occur in the optical receiver provided in the central base station. It is an object of the present invention to provide an optical transmission device and an optical subscriber network in which the signal-to-noise ratio is improved.

One embodiment of an optical transmission apparatus using a subcarrier multiplexing method and a subcarrier multiple access method in combination with a wavelength division multiplexing method according to the present invention for achieving the above technical problem in an optical subscriber network of a wavelength division multiplexing method; a plurality of subcarriers at each wavelength; A multiplexer / demultiplexer for demultiplexing the A-band M wavelength downlink optical signals including and multiplexing the B-band M wavelength uplink optical signals including a plurality of subcarriers in each wavelength; A plurality of optical splitters for splitting the demultiplexed wavelength downlink optical signals into N optical signals; A plurality of optical receivers for receiving an uplink optical signal belonging to a C band; And M optical transmitters for converting the uplink optical signal of the received C band to the B band.

One embodiment of an optical subscriber network using a subcarrier multiplexing and a subcarrier multiple access scheme in a wavelength division multiplexing scheme according to the present invention for achieving the above technical problem is a central base station, a local base station connected by a single optical path with the central base station and the An optical subscriber network of a wavelength division multiplexing system comprising a plurality of subscriber stations connected to a local base station, the optical subscriber network comprising: a plurality of optical transmitters located at the subscriber station and converting data into C-band optical signals for uplink transmission; A plurality of optical receivers located in the local base station and receiving the C-band uplink optical signal; M optical transmitters for converting the received C-band uplink optical signal to B-band; A multiplexer which multiplexes the B-band M wavelength uplink optical signals; A demultiplexer positioned in the central base station and demultiplexing the multiplexed B-band M wavelength uplink optical signals; M optical receivers for converting each of the demultiplexed wavelength optical signals into an electrical signal; A plurality of subcarrier receivers for filtering predetermined frequency band subcarriers in the respective electrical signals; And a plurality of demodulators / demodulators for restoring the data from the subcarriers.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view illustrating an embodiment of a transmission method and a structure of an optical subscriber network using a wavelength division multiplexing method using a sub-carrier-multiplexing and a sub-carrier-multiple access method. Figure showing.

As shown in FIG. 1, the subscriber station 100 to 100-N modulates subscriber information in a form capable of transmitting the information to the network, and modulator / demodulator in each subscriber 100 demodulating the modulated signal into subscriber information. (MODEM: Modulation / Demodulation) 101, the subcarrier signal transmitter 102 in each subscriber 100 for converting the center frequency of the MODEM 101 output signal to an arbitrary subcarrier frequency, and the signal of the subcarrier frequency band C-band optical transmitter 104 in each subscriber 100 converting the subcarrier signal receiver 103 and subcarrier signal transmitter 102 output signal in each subscriber 100 to convert into a frequency that can be input to the optical signal. And an optical receiver 105, a C-band optical transmitter 104, and an A-band optical receiver 105 in each subscriber 100 for receiving a downlink A-band optical signal and outputting a subcarrier signal. Each subscriber to separate / combine A C / A band optical filter 106 in the interior.

The local base station is connected to the C / A band optical filter 106 and a single fiber, and the C / A band optical filter 111 and the local base station within the local base station 110 to separate / combine the light of the C / A band wavelength. The optical receiver 112 and the optical receiver 112 output subscriber subcarrier signals in the local base station 110 receiving the C band subscriber optical signal separated by the C / A band optical filter 111 in the 110 are combined into one. B-band optical transmitter 113 in the local base station 110 that transmits the optical signal, the optical powder in the local base station 110 is connected to the C / A band optical filter 111 in the local base station to optically branch the A-band downward optical signal B / A band optical filter 115 and B / A band in the local base station connected to the device 114, the optical splitter 114 and the B band optical transmitter 113 to separate / combine the light of the B / A band wavelength. In the local base station 110 is connected to the optical filter 115, the wavelength division multiplexing / demultiplexing of the light of the wavelength of the B, A band Light and a multiplexer / demultiplexer (116).

Since the point-to-point transmission is performed between the subscriber station and the local base station, a low cost FP-LD (Fabry-perot Laser Diode) can be used as the subscriber light source and the optical transmitter 104.

2 is a view illustrating another embodiment of a transmission method and a structure of an optical subscriber network using a wavelength division multiplexing method using a sub-carrier-multiplexing and a sub-carrier-multiple access method according to the present invention; Figure showing.

The function of the subcarrier signal transmitter 102 of FIG. 1 may be located in the local base station.

2 is a block diagram of another embodiment of an optical transmission apparatus and an optical subscriber network in which a subcarrier signal transmitter according to the present invention is located at a local base station.

The subscriber's network configuration modulates the subscriber's information in a form that can be transmitted to the network, and modulates / demodulates (MODEM) 101 in each subscriber 100 demodulating the modulated signal into subscriber information. C-band in each subcarrier signal receiver 103 in each subscriber 100 for converting a signal of the subcarrier frequency band into a frequency that can be received by the MODEM 101, and an output signal of the MODEM 101 by converting the output signal into an optical signal. It is connected to the optical receiver 105, the C-band optical transmitter 104 and the A-band optical receiver 105 in each subscriber 100 that receives the optical transmitter 104 and the downlink A-band optical signal and outputs a subcarrier signal. A C / A band optical filter 106 in each subscriber that separates / combines the light of the band wavelengths.

The local base station is connected to the C / A band optical filter 106 and a single fiber, and the C / A band optical filter 111 and the local base station within the local base station 110 to separate / combine the light of the C / A band wavelength. Arbitrary subcarriers of the center frequency of the optical receiver 112 and the optical receiver 112 output signal in the local base station 110 receiving the C band subscriber optical signal separated by the C / A band optical filter 111 in the 110. B-band optical transmitter 113 in local base station 110 to combine the output signal of the sub-carrier signal transmitter 217 in the local base station 110, the output signal of several sub-carrier signal transmitter 217 to convert to a frequency, An optical branch 114, an optical branch 114, and a B band optical transmitter 113 in the local base station 110 connected to the C / A band optical filter 111 in the local base station to optically branch the A-band downward optical signal; B / A within a regional base station connected to separate / combine light with B / A band wavelength An optical multiplexer / demultiplexer 116 in a local base station 110 connected to an inverse optical filter 115 and a B / A band optical filter 115 to split / multiplex / demultiplex light of wavelengths in the B and A bands. Include.

Meanwhile, an embodiment of an optical subscriber network transmission method using a subcarrier multiplexing method and a subcarrier multiple access method in addition to the wavelength division multiplex method shown in FIG. 1 and an entire network including a central base station in a network having the structure thereof are shown in FIGS. 3 and 4. Indicated.

FIG. 3 is a diagram illustrating an embodiment of an optical subscriber network transmission method using a subcarrier multiplexing method and a subcarrier multiple access method in addition to the wavelength division multiplex method shown in FIG. 1 and an entire network including a central base station in a network having the structure thereof.

First, referring to FIG. 3, the center frequencies of the output signals of the MODEM 331 and the MODEM 331 in the central base station 330 serving as a modulator / demodulation unit (MODEM) of the subscriber end may be arbitrarily determined. Subcarrier signal transmitter 332 in the central base station 330 to convert to a subcarrier signal receiver 333, subcarrier signal in the central base station 330 for converting a signal of the subcarrier frequency band into a frequency that can be received by the MODEM 331 Transmitter 332 A-band optical transmitter 334 in central base station 330 for converting the output signal into an optical signal and an optical-receiver 335 in central base station 330 for receiving an uplink B-band optical signal and outputting a subcarrier signal. And an optical multiplexer 336 of the central base station 330 and a optical receiver 335 in the central base station 330 which are connected to the A-band optical transmitter 334 to multiplex the light of the A-band wavelength. The light of the B band wavelength Of the central base station 330 connected to the optical demultiplexer 337, the optical multiplexer 336 and the optical demultiplexer 337 in the demultiplexed central base station 330 to separate / combine the light of the A / B band wavelength. A / B band optical filter 338.

FIG. 4 is a diagram illustrating another embodiment of an optical subscriber network transmission method using a subcarrier multiplexing method and a subcarrier multiple access method in addition to the wavelength division multiplex method shown in FIG. 1 and an entire network including a central base station in a network having the structure.

Referring to FIG. 4, the central base station 430 converting the center frequencies of the output signals of the MODEM 431 and the MODEM 431 in the central base station 430 serving as the MODEM (Modulation / Demodulation) of the subscriber end to an arbitrary subcarrier frequency. Subcarrier signal transmitter 432 and subcarrier signal transmitter 432 and subcarrier signal transmitter 432 output signals in the central base station 430 for converting the signal of the subcarrier frequency band into a frequency that MODEM 431 can receive. A-band optical transmitter 434 in central base station 430 for converting into optical signals and optical receiver 435 and A-band optical transmitter in central base station 430 for receiving uplink B-band optical signals and outputting subcarrier signals. 434 and A / B band optical filters 436 and A / B band optical filters 436 of the central base station 430 which are coupled to the optical receiver 435 to separate / combine the light of A / B band wavelengths. To split the light of the wavelengths of the A and B bands An optical multiplexer / demultiplexer 437 within the central base station 430 to neutralize / demultiplex.

 An optical subscriber network transmission method using a subcarrier multiplexing method and a subcarrier multiple access method in combination with the wavelength division multiplexing method shown in FIG. 2 in which a function of the subcarrier signal transmitter 102 is located in a local base station. Alternatively, the entire network including the central base stations 330 and 430 shown in FIG. 4 may be configured.

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

As described above, the present invention is effective in reducing subscriber network construction and maintenance costs by using a subcarrier multiplexing method and a subcarrier multiple access method in a wavelength division multiplexing method, and using a bidirectional optical communication technology that performs up / down communication through a single fiber. have.

In case of the subcarrier multiple access method, the local base station receives the subscriber subcarrier optical signal and transmits several subcarrier signals to one optical transmitter to improve the signal quality by improving the signal-to-noise ratio by preventing OBI from occurring at the receiver equipped in the central base station. This has the effect of accommodating more subscribers.

OBI does not occur, so the number of subscribers limited by thermal noise is acceptable.

Claims (14)

In a wavelength division multiplex optical subscriber network; A multiplexer / demultiplexer for demultiplexing the A-band M wavelength downlink optical signals including a plurality of subcarriers at each wavelength and multiplexing the B-band M wavelength uplink optical signals including a plurality of subcarriers at each wavelength; A plurality of optical splitters for splitting the demultiplexed wavelength downlink optical signals into N optical signals; A plurality of optical receivers for receiving an uplink optical signal belonging to a C band; And And M optical transmitters for converting the received C-band uplink optical signal to the B-band. The method of claim 1, The multiplexer / demultiplexer; The optical splitter, the optical receiver and the optical transmitter are located in a local base station for multiplexing and transmitting the converted B-band M wavelength uplink optical signals. The method of claim 2, And a plurality of subcarrier signal transmitters for converting a center frequency of the optical receiver output signal into a predetermined subcarrier frequency, wherein the optical transmitter converts at least one subcarrier into the B-band optical signal. Optical transmission device of a multi-mode optical subscriber network. The method of claim 1, wherein the uplink optical signal of the received C band is An optical transmission apparatus of a wavelength division multiplex optical subscriber network, wherein the data is an optical signal loaded on a predetermined frequency band subcarrier. The method of claim 1, A plurality of B / A band optical filters for separating or combining any one of the demultiplexed A-band downlink optical signals and one of the optical signals converted into the B bands; And a plurality of C / A band optical filters for separating or combining any one of the branched N optical signals and one of the upstream optical signals of the C band. Optical transmission device of a multi-mode optical subscriber network. The method of claim 1, A plurality of carrier transmitters for converting data into subcarriers of a predetermined frequency band; M optical transmitters for converting at least one or more subcarriers into an A-band optical signal; And a multiplexer for multiplexing the M A-band optical signals, wherein the carrier transmitter, the optical transmitter, and the multiplexer are located at a central base station that multiplexes and transmits the A-band M wavelength down optical signals. An optical transmission device for a wavelength division multiple access optical subscriber network. The method of claim 1, An optical receiver configured to receive an optical signal of the branched N optical signals and convert the optical signal into an electrical signal; A subcarrier signal receiver for filtering a predetermined frequency band subcarrier from the electrical signal; And a modulator / demodulator for demodulating the filtered subcarriers into subscriber data, wherein the optical receiver, the subcarrier signal receiver, and the modulator / demodulator are located at a subscriber end providing subscriber service to the subscriber. Optical transmission device of wavelength division multiplex optical subscriber network. The method of claim 1, A B / A band optical filter for separating or combining the multiplexed B band M wavelength optical signals and the A band M wavelength optical signals transmitted downward; A demultiplexer which demultiplexes the multiplexed B-band M optical signals; M optical receivers for converting each of the demultiplexed wavelength optical signals into an electrical signal; A plurality of subcarrier receivers for filtering predetermined frequency band subcarriers in the respective electrical signals; And a plurality of demodulators / demodulators for reconstructing data transmitted from the subscribing end from the output subcarrier, wherein the B / A band optical filter, the optical receiver, the demultiplexer, the subcarrier receiver, and the demodulator / demodulator The optical transmission apparatus of a wavelength division multiplex optical subscriber network, characterized in that located in the central base station for multiplexing the A-band M wavelength downlink optical signal. The method of claim 1; A plurality of subcarrier transmitters for converting data of each subscriber into subcarriers of a predetermined frequency band; And a plurality of optical transmitters for converting at least one or more of the subcarrier output signals into an optical signal of the C band, wherein the subcarrier transmitter and the optical transmitter are located at a subscriber end providing subscriber service to the subscriber. An optical transmission device of a wavelength division multiplex optical subscriber network. The optical transmitter of claim 9, wherein the optical transmitter is An optical transmission apparatus of a wavelength division multiplex optical subscriber network, characterized in that it is a FP-LD (Fabry Perot Laser Diode). In a wavelength division multiplex optical subscriber network consisting of a central base station, a local base station connected to the central base station by a single ray, and a plurality of subscriber stations connected to the local base station, A plurality of optical transmitters located at the subscriber end and converting data into C-band optical signals for uplink transmission; A plurality of optical receivers located in the local base station and receiving the C-band uplink optical signal; M optical transmitters for converting the received C-band uplink optical signal to B-band; A multiplexer which multiplexes the B-band M wavelength uplink optical signals; A demultiplexer positioned in the central base station and demultiplexing the multiplexed B-band M wavelength uplink optical signals; M optical receivers for converting each of the demultiplexed wavelength optical signals into an electrical signal; A plurality of subcarrier receivers for filtering predetermined frequency band subcarriers in the respective electrical signals; And a plurality of modulators / demodulators for recovering the data from the subcarriers. The method of claim 11, wherein A multiplexing unit located at the central base station and multiplexing A-band M wavelength downlink optical signals including a plurality of subcarriers in each wavelength; A demultiplexer located at the local base station and demultiplexing the A-band optical signal; A plurality of optical splitters for splitting the demultiplexed wavelength optical signals into N optical signals; An optical receiver located at the subscriber end and receiving an optical signal of the branched optical signal and converting the optical signal into an electrical signal; A subcarrier signal receiver for filtering a predetermined frequency band subcarrier from the electrical signal; And a demodulator / demodulator for demodulating the filtered subcarriers into subscriber data. 12. The method of claim 11, wherein the uplink optical signal of the received C band is And an optical signal in which the data is carried on a predetermined frequency band subcarrier. The method of claim 11, wherein And a plurality of subcarrier signal transmitters for converting a center frequency of an optical receiver output signal of the local base station into a predetermined subcarrier frequency, wherein the optical transmitter converts at least one subcarrier into the B-band optical signal. Wavelength Division Multiplexing Optical Subscriber Network.

Images