KR100421850B1 - Method for realinzing ATM signaling of Network Interface Equipment in LMDS System - Google Patents

Abstract

In the Local Multipoint Distribution Service (hereinafter referred to as LMDS) system, especially in the LMDS system, the network connection device directly controls the subscriber device, and the headend device merely acts as the aggregation function. The present invention relates to a method for effectively performing ATM signal processing of a network. A network access device having a protocol defining an interface between a user and a network and a network interface provides a method for processing user data transmitted from a plurality of subscriber devices through a wireless medium. A network in an LMDS system that directly performs and transmits information on resources allocated by the signal processing to a headend device according to the traffic level so that the headend device can allocate radio resources using the transmitted information. The present invention relates to an ATM signal processing method of an access device.

Description

Implementation method of ATM signal processing of network access device in LMS system {Method for realinzing ATM signaling of Network Interface Equipment in LMDS System}

The present invention relates to an LMDS system, and more particularly, to a method in which a network access device directly controls a subscriber device in an LMDS system, and a headend device merely performs a converging function to effectively perform ATM signal processing of the LMDS system. .

In general, due to the development of wireless communication technology and the development of the millimeter wave band, a broadband wireless subscriber network (B-WLL), which is advantageous in terms of ease of network construction, scalability, and economics, is in the spotlight.

In order to realize the broadband wireless subscriber network (B-WLL), Korea announced the frequency in the 20 GHz band, and similar systems include the Canada's Local Multipoint Communication System (LMCS) and the US Regional Multipoint. Distributed Services (LMDS) and ATM Wireless Access (AWA) in Japan are being studied.

Standardization in relation to broadband wireless subscriber networks (B-WLL) is most prominent in the work of the Digital Audio Visual Council (abbreviated as DAVIC).

DAVIC publishes the 1.0 specification up to the 1.3 specification and presents the only specific standard for the broadband wireless subscriber network (B-WLL). DAVIC mentions down time division multiplexing (TDM), up time division multiple access (TDMA) multiple access schemes, and downlink, uplink frame structure, and media access control protocol. have.

In Korea, Ministry of Information and Communication Announcement No. 1997-49 specifies the frequency for the subscriber line of the broadband wireless subscriber network (B-WLL), which allocates 2 하향 down from 25.5 ㎓ to 27.5 에서 for bidirectional broadband service in the 20 ㎓ band. Upwardly, 500 MHz of 24.25 Hz to 24.75 Hz was allocated. Of these, the 800 MHz band of 26.7 GHz to 27.5 GHz was temporarily designated for cable television (CATV) transmission.

As such, ultra-high-speed broadband multimedia service using subscriber line frequency in the millimeter wave band (2MHz downwards 25.5㎓-27.5㎓ and 500MHz upwards 24.25㎓24.75㎓) for subscribers within a radius of about 2-5km. An LMDS system that provides is a system developed to deliver multi-channel TV programs to subscribers as a competition for wirelines in the cable television market.

Initially mainly used for cable TV distribution, it gradually developed into a two-way digital system, and the services that a system of two-way high-speed wireless communication concept can provide include voice telephone service, data communication service, interactive video service, voice / data / There are multimedia services and dedicated line services that combine video, and have subscriber types such as general public network subscribers, private network subscribers, and public network transmission relays.

In addition, MMDS, a broadband wireless subscriber network that provides wireless cable television service or high-speed Internet service using subscriber line frequencies in the millimeter wave band (2.535 GHz to 2.655 GHz) for subscribers within a radius of about 30 to 50 km. Standards are also presented in the DAVIC 1.3 specification.

1 is a block diagram showing a general LMDS system configuration.

Referring to FIG. 1, the LMDS system may be broadly classified into a service provider 100 and a customer premises equipment unit (CPE) 200.

First, the service provider 100 may include a central office unit (COU) 110, a head-end unit 120, and a hub outdoor unit (HOU) 130. The subscriber unit (CPE) 200 is classified into a home subscriber unit 210 and an office subscriber unit 220.

The central office device (COU) 110 may appropriately multiplex the program and service contents supplied from each program provider, that is, the digital data stream through the network access device 111, thereby providing a headend device ( Head-end unit) 120.

The network connection device 111 performs a function of routing and multiplexing / demultiplexing the data streams transmitted from the ATM switch 113, the telephone switch 112, and the digital line access switch (DACS) 114.

ATM switch 113 is connected to the Internet (Internet) and the transmission control protocol / Internet Protocol (TCP / IP) to provide ATM-LAN service to the subscriber device (CPE) 200, the ATM cell structure data Analyze and exchange the data with the network connection device 111 by configuring the data in the form of a frame that can accommodate 44.736 Mbps digital signal level (DS-3) or 155.52 Mbps synchronous transmission mode (STM-1). Do this.

The telephone exchange 112 performs a function of establishing a mutual communication path when connecting to the PSTN, and accepts the V 5.2 protocol and is connected to the network connection device 111.

The DACS 114 converts the data transmitted from the leased line into a digital signal level (DS-1E) of 2.048 Mbps, a digital signal level (DS-3) of 44.736 Mbps, or a synchronous transmission mode of 155.52 Mbps. It is configured in the form of a frame that can accommodate the STM-1) and performs a function to deliver to the network connection device (111).

In addition, the central office unit (COU) 110 is provided with a network management unit 117 responsible for network management of the entire system, the integrated network management control station 116, and the billing processing unit 115 in charge of the subscriber billing; have.

The network management device 117 and the integrated network management control station 116 are in charge of all operations, state management, and information management of the subscriber device (CPE) 200 through information exchange with the network connection device 111. It is also responsible for network connection and state management between the network connection device 111 and the base station device 130.

To this end, a simple network management protocol (SNMP) / common management information protocol (CMIP) is used between the network access device 111 and the network management device 117. Network status data is received from 111 to perform network management. The same protocol is used between the network management device 117 and the integrated network management control station 116.

The billing processing unit 115 performs a task related to billing of the subscriber by using a centralized billing management method (CAMA: Centralized Automatic Message Accounting).

The head-end unit 120 modulates downstream data of the ATM cell structure transmitted from the network access unit 111 and transmits the data to the base station apparatus 130, and in the base station apparatus 130. The demodulated upstream data is demodulated and transmitted to the network access device 111.

The base station apparatus 130 amplifies and frequency-converts the downstream data transmitted from the head-end unit 120 and transmits it to the subscriber through a high-directional antenna, and the upstream data received through the radio section. Amplifies and converts the frequency to the head-end unit (120).

Sending and receiving downlink and upstream data of the millimeter wave band (2 GHz of 25.5 GHz to 27.5 GHz and 500 MHz of 24.25 GHz to 24.75 GHz) through the wireless section with the service provider 100 described above. The subscriber device (CPE) 200 may be classified into a home subscriber device 210 for home use and an office subscriber device 220 for office use.

The home subscriber station 210 has a peripheral device such as a TV, a telephone, a personal computer, and slightly differently, the office subscriber device 220 has a small capacity private automatic branch exchange (PABX) to support voice service. In other words, you have a router for data services.

The home subscriber unit 210 is an outdoor unit (ODU: Outdoor Unit) 211 that is installed outdoors for communication with the service provider 100, and is installed indoors and is a network interface unit (NIU) and a set-top unit (STU). It is composed of an indoor unit (IDU: Indoor Unit) 212 including a set-top unit, and the office subscriber unit 220 is also an outdoor unit (ODU) 221 and an indoor unit (IDU) 222. It is composed.

The interface formed between the network interface unit (NIU) and the set-top unit (STU) included in the home subscriber station 210 and the office subscriber unit 220 is an electrical system of a large integrated microprocessor (LSI) for protocol processing of ATM. It follows the universal interface, UTOPIA (Universal Test & Operations PHY Interface for ATM).

In addition, each outdoor unit (ODU) 211 and 221 of the home subscriber station 210 and the office subscriber station 220 converts and amplifies downstream data inputted through a high-directional antenna to a network interface unit (NIU). Alternatively, frequency conversion and amplification of upstream data transmitted from a network interface device (NIU) is transmitted through a high-directional antenna to a wireless section.

The network interface device (NIU) provided in the indoor unit (IDU) of each subscriber device (210,220) interfaces with the outdoor unit (ODU) 211,221 and peripheral devices which are a plurality of data terminals, and each set-top device ( STU) provides peripheral devices with communication functions such as video server, reception and exchange of video signal, and data communication service support function.

In addition, the office subscriber device 220 may be provided with a local area network server (LAN Server) for a plurality of clients (Client) that wants a local area network service (LAN), Ethernet (Ethernet) through a local area network server (LAN Server) ) Can be used.

As such, the DAVIC specification of the LMDS system and the specification of the system developer did not provide a description and description of ATM signal processing.

In particular, due to technical protection barriers of developed countries, LMDS technical matters are not disclosed, and thus, there is no mention of an implementation method for ATM signal processing of the LMDS system.

The present invention has been made to solve such a problem, the network connection device in the LMDS system is responsible for signal processing for ATM, the head-end device to implement the ATM signal processing method to allocate dynamic resources without performing switching The purpose is to provide.

In the LMDS system according to the present invention for achieving the above object, a feature of the ATM signal processing implementation method of the network access device, the network access device having a protocol defining the interface between the user and the network and the network interface from the wireless medium from multiple subscriber devices Directly performs a signal processing procedure for the user data transmitted through the system, and transmits the information on the resource allocated in the signal processing to the headend device according to the traffic level to the headend device using the transmitted information. This means that radio resources can be allocated.

Preferably, in order to transfer information on resources allocated in the signal processing according to the traffic level of the network access device, it is realized by a bearer access control protocol (BCCP), and the information is a protocol having a radio medium control function. It is transmitted to the headend device through.

Herein, the information transmitted through the protocol having the wireless medium control function is transmitted to a MAC processing processor included in the headend device, and the MAC processing processor transmits the corresponding timeslot to the subscriber device using the transferred information. By assigning two-way communication service.

In addition, the head-end device is to allocate a radio resource, the local identifier for distinguishing between the subscriber device and a plurality of applications in the subscriber device establishes a fixed correspondence with the virtual path and the virtual channel identifier, the signal According to the negotiation by the processing procedure, a virtual connection to the corresponding virtual path and virtual channel identifier corresponding to the local identifier is made.

1 is a block diagram showing a general LMDS system configuration.

Figure 2 is a block diagram showing the configuration of the network connection device in the LMDS system according to the present invention.

Figure 3 is a block diagram showing the configuration of the head end device in the LMDS system according to the present invention.

4 is a diagram illustrating an ATM signal processing procedure of an LMDS system according to the present invention.

* Description of the symbols for the main parts of the drawings *

300: network connection device 301 to 306: connection module

323: SAR 350: ATM signal processing device

370: call processing device 371: MAC control unit

380: network management access device 390: management layer

400: head end device 410: central processing unit

420: Mac processing unit 430: Modem unit

440: frequency converter 450: combiner / divider

460: light conversion unit 500,510: subscriber unit (CPE)

Hereinafter, a preferred embodiment of an ATM signal processing method of a network access device in an LMDS system according to the present invention will be described with reference to the accompanying drawings.

When the headend device has a switching function, it may provide a virtual channel connection (VCC) function between subscriber devices. However, as in the present invention, when there is no switching function, the subscriber station is directly controlled by the network access device, and the headend device has only assembling function.

In particular, in the present invention, the network access point is in charge of controlling all services, additional functions, statistics, and billing, and the network access point has a bearer connection control protocol (BCCP) according to its traffic level. Information about the resource allocated by ATM signaling is delivered to the " LMDS MAC " layer, allowing the headend device to allocate radio resources using this information.

In the head-end device, fixed between Local Identifier (LI) and Virtual Path Identifier / Virtual Channel Identifier (VPI / VCI) that distinguishes each subscriber station and distinguishes multiple applications within each subscriber station. Will establish the correspondence relationship.

Here, the virtual access to the virtual path identifier / virtual channel identifier (VPI / VCI) corresponding to each local identifier (LI) is supported by the required quality of service according to negotiation by ATM signal processing.

In the present invention, in setting up a virtual channel connection (VCC) by signal processing, the virtual channel connection (VCC) (0/1) for meta signal processing and the virtual channel connection (VCC) (0) for signal processing are set. / 5) Use Virtual Channel Connection (VCC) (0/5) for signal processing during setup.

2 is a block diagram showing the configuration of a network connection device in an LMDS system according to the present invention.

In general, the network access device 300 transmits the program and service contents, that is, the digital data streams, which are supplied from each program provider, to the head-end unit by appropriately multiplexing them. Play a role.

In addition, the network connection device 300 performs a function of routing and multiplexing / demultiplexing data streams transmitted from an ATM switch, a telephone switch, and a digital circuit access switch (DACS).

To this end, the network connection device 300 is provided with a plurality of connection modules (301 to 306) for connecting to each switch.

The network connection device 300 includes a call processing function by the call processing device 370, a signal processing function by the ATM signal processing device 350, and a call control by a usage parameter control device (UPC) 323. A function, an operation management function and a resource management function by the management layer 390 having an operation management device (OAM) 391.

The network connection device 300 receives each signal from the plurality of exchanges to the connection modules 301 to 306, finds the corresponding frame synchronization from each of the received bit strings, and extracts the payload. In addition, by generating a frame to be transmitted, the payload is mapped (mapping).

The ATM switch 322 switches ATM cells, and the usage parameter controller (UPC) 323 is networked from deliberate operation as well as accidental malfunctions that may affect the quality of service for these calls for already established call connections. To protect the resources, it detects violations of negotiated parameters and performs appropriate control.

The ATM signal processing apparatus 350 is for user-to-network interface (UNI) and network-to-network interface (NNI), and is fixed in the form of a fixed virtual connection (PVC) or switched virtual connection (SVC). ATM services such as Constant Bit Rate, Variable Bit Rate, Unspecified Bit Rate, and Available Bit Rate are provided.

Therefore, when assigning a channel to a subscriber after the ATM signal processing procedure, the information about the channel is transmitted to the MAC processing processor of the headend device through the bearer access control protocol (BCCP), and the MAC processing processor transmits the received channel information. By assigning the appropriate timeslot to the subscriber, the user data is transmitted.

Figure 3 is a block diagram showing the configuration of the head end device in the LMDS system according to the present invention.

Referring to FIG. 3, the head-end unit 400 modulates down channel data of an ATM cell structure transmitted from the network access device 300 and transmits the down channel data to the base station device. Demodulates upstream channel data delivered from. The detailed configuration thereof is as follows.

Head-end unit 400 includes a central processing unit 410, a MAC processing unit 420, a modem unit 430 having a plurality of downstream and upstream modems, a plurality of upstream converters and A frequency converter 440 having a downstream converter, a combiner / divider 450, and an optical converter 460.

Hereinafter, the operation of the head end device will be described.

The central processing unit 410 controls the operation state of the modem unit 430 and the frequency converter 440.

The MAC processing unit 420 is connected to the network access unit 300 to perform multiplexing and demultiplexing of ATM data for synchronous transfer mode (STM-1) -class ATM communication at 155.52 Mbps, and from the network access unit 300. A data format for performing routing operation by analyzing the received data and sending constant bit rate data, variable bit rate data and control data to each subscriber device 500 or 510 according to the received data type. Or to analyze and transmit the data transmitted from the subscriber device (500,510) to the network connection device (300).

Here, the form of the downstream data is an MPEG-2 transport stream according to the DAVIC recommendation, and the Mac processing unit 420 forms such a downstream data format and delivers it to the downstream modem.

In addition, MAC control data through the upstream is processed by the MAC processing unit 420, ATM signal processing is transmitted to the network access device 300 through the bearer connection control protocol (BCCP).

The downstream modem of the modem unit 430 uses Quadrature Phase Shift Keying (QPSK) in its initial implementation. Reed-solomon encoding 188 bytes of downstream data received from the MAC processing unit 420. 204 bytes are generated by adding 16 bytes of surplus data, and quadrature phase shift is performed after convolution interleaving (I = 12, M = 17) and convolutional coding (R = 7/8, K = 7). Will be performed. Thereafter, the carrier frequency of 70 MHz is transmitted to the downstream converter of the frequency converter 440.

The downstream converter converts the modulated signal transmitted from the downstream modem into the channel frequency of the intermediate frequency band of 950 to 2,050 MHz and sends it to the combiner / divider 450.

The combiner / divider 450 collects the channel frequencies of the three-port intermediate frequency bands transmitted from each downstream modem to the optical converter 460, and the optical converter 460 converts them into optical signals. Transmit to base station.

On the contrary, the upstream data transmitted from the subscriber apparatuses 500 and 510 is down-frequency converted to 400 to 700 MHz in the base station apparatus and transmitted to the headend apparatus 400 through the optical line.

The light conversion unit 460 of the head end device 400 receives the upstream data through the optical line and converts it into an electrical signal, and the combiner / divider 450 separates the converted electrical signal into three ports. Send to the frequency converter 440.

The upstream converter of the frequency converter 440 down-converts the received upstream data to a frequency of 70 MHz and sends it to the upstream modem.

The upstream modem of the modem unit 430 uses a differential orthogonal shift method (DQPSK) in an initial implementation. Reed-solomon decoding of 63 bytes of upstream data is a forward error correction technique. (63, 53, t = 5) is converted into an ATM cell of 53 bytes and transferred to the MAC processing unit 420.

The MAC processing unit 420 analyzes the transmitted upstream data. If the analyzed data is control data, the MAC processing unit 420 transmits the data to the call processing unit 370 of the network access unit 300 through the bearer access control protocol (BCCP). The data to be transmitted and sent to the network side is multiplexed into 155.52 Mbps of data and sent to the network access device 300. At this time, the network access device 300 delivers the multiplexed ATM cell to the corresponding destination.

4 is a diagram illustrating an ATM signal processing procedure of an LMDS system according to the present invention, the contents of which are described in the operation description of the network connection apparatus and the head end apparatus described above.

As described above, according to the method for implementing ATM signal processing of the network access device in the LMDS system of the present invention, since the network access device directly controls the subscriber device by ATM signal processing, and the headend device performs only the aggregation function, Economical system implementation is easy.

In addition, ATM signal processing is performed in the network access device, and MAC processing function is performed in the headend device, so it is easy to implement the entire system.

Claims (5)

A network access device having an ATM signal processing device that provides an ATM service for an interface between a user and a network and transmits channel information for allocating a channel to a subscriber after processing an ATM signal to the MAC processing unit of the headend device. Making a step; Analyzing, by the Mac processing processor of the headend device, channel information received from the network connection device; Allocating radio resources between a subscriber station and a base station device according to the analyzed channel information; And routing the ATM cell data transmitted from the network access device to the subscriber device via the radio resource. The method of claim 1, wherein the information is transmitted to a MAC processing processor of the headend device through a protocol having a wireless medium control function. The method according to claim 2, wherein the MAC processing unit provides a bidirectional communication service by allocating a corresponding timeslot to the subscriber device using the transferred information. . The method of claim 1, wherein the head-end device is to allocate a radio resource, the local identifier for distinguishing between the subscriber device and a plurality of applications in the subscriber device establishes a fixed correspondence with the virtual path and the virtual channel identifier A method for implementing ATM signal processing of a network access device in an LMDS system comprising: The method of claim 1, wherein a virtual connection is made to a corresponding virtual path and a virtual channel identifier corresponding to the local identifier after the signal processing procedure.