KR100404656B1 - Measurement System within Cable Modem Board - Google Patents

Abstract

The present invention is a small low-cost that can test the troubleshooting of the network in the event of network failure and the installation of the Data OverCable Service Interface Specificatlon (DOCSIS) standard cable modem in a bidirectional CATV network (or HFC network: optical coaxial mixed network) using a cable modem The present invention relates to a measuring instrument that can be upgraded, and in particular, a cable modem can be used to perform all functions as a conventional cable modem while connected to a network.

Description

Instrument using cable modem {Measurement System within Cable Modem Board}

A cable modem is a device that connects a PC to a cable TV line to receive data at speeds up to 10 Mbps. At this data rate, you can watch TV when installed with a set-top box, as well as a 56-Kbps phone modem that's commonly used, as well as an ISDN that delivers 128-Kbps. For a PC connection, the cable line must branch off to the TV, one to the TV and one to the cable modem, as shown at left. All cable modems must be connected to the cable TV company's coaxial cable to communicate with the CMTS at the cable station in each area. All cable modems can only exchange data with CMTS and cannot exchange signals with other cable modems connected to the same line.The actual bandwidth of the cable TV line for Internet services is downward (from the station to the subscriber side). ) Up to 27 Mbps, and up to 2.5 Kbps in subscriber direction. However, if a local cable company is connected to the Internet at a speed of T-1, or 1.544 Mbps, subscribers are limited to that speed as well. The advantage is that you are always connected to the network, and that you pay a certain amount of money every month, so it can be advantageous in terms of fees for those who spend a lot of time. And a measuring instrument for fault determination. In particular, a cable modem can be used to install a data over cable service interface specification (DOCSIS) standard cable modem in a bidirectional CATV network (or HFC network) and to troubleshoot the network in the event of a network failure. The HFC network is composed of an optical fiber and a coaxial cable. As a broadband transmission network that can transmit a large amount of data (Internet, cable TV, crime prevention, disaster prevention, remote meter reading, automatic control) from optical station to subscriber and ONU using optical cable, and coaxial cable from optical station to subscriber On the other hand, it supports a wide bandwidth that can be connected at 9600bps ~ 30Mbps per channel of 6MHZ bandwidth, but in Korea, it can transmit up to 10Mbps considering the interface with a PC. The optical cable section from the located ONU consists of Star type, and the coaxial cable section from ONU to the subscriber's house consists of Tree & Branch type. Optical cable section is optical transmitting and receiving device. Up and down optical transmission line is composed by using optical cable, and coaxial cable section is divided up and down by using coaxial amplifier (TBA), passive device (Splitter, Tap-off, etc.) and coaxial cable. The HFC network is a bidirectional system capable of transmitting a downlink signal from an optical end station to a subscriber (home) and an uplink signal transmitted from the subscriber end to the optical end station. (6MHz to 1CH) to transmit data, such as the Internet. Currently, the uplink communication band (subscriber → broadcasting station) available for HFC network is 5 ~ 42MHz, the downlink communication band (broadcasting station → subscriber) is 54 ~ 750MHz, and the downlink frequency band of 550 ~ 750MHz is used for future digital broadcasting service. The advantage of HFC network is that it provides high speed internet service of up to 10Mbps and provides various multimedia services up to several hundred times faster than general telephone line modem or ISDN. In addition, HFC network does not require a separate connection process because it can use the internet right after turning on the computer like LAN environment.Because broadband cable network is used, two-way service or T-Commerce can be used when switching to Internet and TV as well as digital TV. It is easy to implement, and the service area is divided into several cells, and since each cell is composed of independent networks, it is possible to immediately respond to cell division when subscribers increase, and the operation of the network is easy. Since the section is installed outdoors, it may be relatively difficult compared to the digital transmission network due to the possibility of external environmental influences such as the climate and the inflow of upward noise, but it is now stable in both directions due to the development of NMS (Network Management System). Additional services are available HFC network as of the end of April 2002 The Internet network, which is used by more than 3 million people, about 35% of 8.5 million people, is one of the world's top contributors to ADSL and Korea's first broadband penetration rate. lost. The general public is familiar with ADSL but not with HFC network. In fact, the number of high-speed Internet subscribers using HFC networks is far higher than that of ADSL, and even in the US, HFC network users are more than twice as large as ADSL users. The era of continuous convergence of technology and the convergence of telecommunications and broadcasting was possible. HFC network using broadband cable network can be used for broadcasting, so it is economical network that can fully cover the digital era by real-time internet and TV watching as well as interactive service or T-Commerce during digital conversion without reinvestment. It was time for the value to come into play, with the introduction of the HFC network as a result of the launch of the cable TV business, which has been promoted in Korea to improve cultural standards and bridge regional gaps through various information channels. In 1995, the HFC network was established with the start of comprehensive cable broadcasting, and the project was divided into program providers (PP), broadcasting station operators (SO), and transmission network operators (NO) in three divisions, and Korea Electric Power established the first two-way broadband HFC network in Korea. In 1997, it succeeded in providing the first two-way cable modem pilot service in Korea, and promoted high-speed internet business using cable modem.In January 2000, Powercom, a backbone telecommunications company, was established and ISP (Durnet, Hanaro Telecom, Onse Telecom) Since then, as the number of high-speed Internet subscribers has exploded, the economics of HFC networks have been spread in Durunnet and Hanaro Telecom, and HFC networks have been built independently in some regions. Data communication is as fast as 10Mbps or more. From 1994 to 1995, digital compression technology began to be introduced into the cable TV market, allowing tens to hundreds of channels to fit into the space on the cable that occupied only one channel. Cable modems are a way of using the extra bandwidth that cable TV does not use. The cable modem can upload at low bandwidths of 0 to 52 MHz and download at high bandwidths of 450 to 750 MHz for fast communication.

In general, modems are installed to obtain various information by connecting a data terminal device to a public network. In the early modems, analog signals were handled, but digital signals have recently been increasing.

In addition, as the function and range of advanced information services using communication equipment have recently expanded, the interest in modems is increasing day by day. The services provided through the CATV transmission network are most commonly used for cable TV, high-speed Internet, and digital TV, VolP, New services such as VOD and remote meter reading are expected to be provided. As such various services are provided through a single medium, the evaluation of signal quality is only analog measurement, which is a cable TV quality measurement means, and digital quality measurement for each service is required. Currently, spectrum analyzers can be used to analyze digital signals in CATV networks, but this equipment is expensive and bulky, which is very inconvenient for workers who need to secure mobility for maintenance of the network. There is a need for portable measuring instruments that are easy to use. In general, in order to access the high-speed Internet using a cable modem, the CMTS must be connected first. To this end, various communications are exchanged by a complex communication protocol. The process of accessing the subscriber network, including cable modem and CMTS, is completely unknown to the user. However, the device was devised so that the user can read the process through the console terminal of the modem unit. As can be seen from the figure above, it can be seen that the cable modem has shown the main procedure of communicating with the CMTS. In other words, it is a screen showing a registration state in which a downlink signal is first searched, an uplink signal is communicated with a CMTS, connected, and an IP is allocated from a DHCP server, and a corresponding cable modem is available. Although this information was unknown to the actual cable modem user, the present invention shows the progress of the cable modem to check whether there is a problem with the cable or the DHCP server.

The major obstacles that occur in high-speed Internet services using cable modems are the obstacles between cable modems and CMTS. The main types are (1) CMTS is pinged but not telnet, (2) Connection is lost due to increase of Flap, (3) Connection is interrupted due to decrease of SNR, (4) Cable modem If this link is available but does not receive an IP from DHCP, (5) If the modem receives an IP after replacing the modem, but the PC does not receive an IP, (6) The modem is OK for the subscriber who assigned the fixed IP (7) In case that cable modem is not connected in CMTS, (8) When PC and modem are assigned but IP is not serviced. (9) Subscriber is assigned IP but not serviced. When such an error occurs in the user during use, the Internet subscriber requests A / S to the service company and the technician in charge visits the subscriber and checks the connection status of the cable modem where the CMTS is installed. Headquarters Call) to check for abnormalities or to replace the new modem to see if the barrier is removed. In this way, CMTS operations managers of the headquarters and branch offices became subscribers' complaints because the technicians were busy when the telephone was busy and the telephone call was not made. However, this instrument allows the technician to determine the obstacles and perform the task by knowing the process and result of communicating with the cable modem, CMTS, DHCP server, TOD server and TFTP server. The above picture is an embodiment of the present invention, and the console terminal of the cable modem and the cable modem control unit are connected in serial communication so that the cable modem transmits the whole process and up and down signal analysis elements connected to the CMTS to the control means. The conveyed elements are displayed by the control means for display by the user.

Therefore, an object of the present invention is to implement the measurement equipment for the installation and troubleshooting of the DOCSIS standard cable modem as well as the quality analysis for each section of the bidirectional CATV transmission network. In addition, the present invention should be able to determine the digital transmission status and cause of service failure of a network using a CATV (Cable Modem Termination System) and using a CATV network.

1 is a structural diagram of a measuring instrument using a cable modem

2 is a schematic diagram of a cable modem unit

3 is a measurement block diagram measured in the cable modem unit.

<Description of Symbols for Main Parts of Drawings>

1: cable modem unit 2: control means

3: display means 4.: power supply means

5.: Storage means 6.: Input means

7.: Communication means 8.: Output means

9.: cable modem control means 10.: storage means

11.: Operation status display means 12.: Output means

13.: Tuner 14.: Console terminal

Cable modem measuring apparatus of the present invention that can achieve the above object in the CATV network in measuring and analyzing the up and down signals in the cable modem unit (1), the measurement requirements of the user An input means (6) for inputting an input, a display means (3) capable of displaying measurement results for an input measurement item, and a storage means (5) for storing an S / W such as an OS used for the measurement result or control means , Output means (8) for moving the measurement results stored in the storage means to the outside of the instrument, power supply means (4) for supplying power to drive the instrument, cable modem unit (1) and control means in the entire process (2) All signal transmission and control through the communication means (7) to enable this data communication, the cable modem unit, input means, output means, display means, power supply means, storage means, communication means, etc. throughout the measurement process Is composed of the control unit (2) to enable a feature that.

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

1 is a structural diagram of an instrument using a cable modem

2 is a structural diagram of a cable modem unit

3 is a measurement block diagram measured inside the cable modem unit.

It is installed at the end or branch point of CATV network to measure the main communication parameters of up and down digital signals. When a user inputs a measurement item through an appropriately selected input means (key pad, touch screen, etc.), the controller interprets it and requests the corresponding measurement parameter from the modem part through a communication method and a line connected to the modem part. The control unit responds to the requested value of the parameter, and the control unit displays the measured value on the display unit. However, in order to deliver the measurement parameter values required by the modem unit, the signals on the line connected to the modem unit must be demodulated (because of the RF modulated signal). The cable modem unit is used for this purpose. The main components consist of tuner, modem chip set, SDRAM, Flash Memory, Ethernet and serial interface. The modem chip set consists of various peripherals such as a QAM receiver, DOCSIS MAC, uplink QPSK / QAM burst transmitter, CPU, Ethernet MAC and PHY. In the past, modem chip sets consisted of three to four semiconductor chips, but now they are available in single chip form. 3 shows main communication parameters measured at the modem unit-Level, SNR, Constellation, Pre-ES (errored Second), Post-ES, SES (Severely Errored Rate), Pre-BER (Bit Error Rate), Post-BER And a measurement block diagram of a packet error rate (PER).

In order for the control unit to execute the input command, communicate with the modem unit, and display the measured values on the display unit, a well-programmed program must be driven. Such an application program or O / S program for executing the application program must be loaded internally, and a storage means is required for this purpose. If you need to deliver the measured result to any form (file, print, etc.) to the outside (computer or output means, etc.), output means are required for this purpose, and power must be supplied for all these operations to take place. Therefore, in the case of outdoors, a rechargeable battery may be used or indoor AC power may be used if indoors, and a power supported by a vehicle may be used inside a vehicle.

As described above, in order to measure the measurement items required by the user, the modem unit is required. Means transmitted from the modem unit to the controller can be implemented in various ways. Serial communication and parallel communication There are USB, PCI Bus, Ethernet, etc. and it can be selected appropriately according to the type and amount of data to be transferred. In particular, for miniaturization of the product, it is possible to request and transmit measurement data by directly connecting to the control unit by using one or more spare terminals of the MAC chip of the core chip set of the modem unit. In this case, the modem unit and the control unit can be implemented on a single printed circuit board, thereby miniaturizing the measuring instrument.

Consists of a control unit-usually using a CPU-to enable all signal transmission and control through input means, output means, display means, power supply means, storage means, communication means, etc.

Among the services provided through the CATV transmission network, cable TV and broadband internet are the most common, and new services such as digital TV, VolP, VOD, and remote meter reading are expected to be provided. Although various services are provided through one medium, the evaluation of signal quality is only analog measurement, which is a measure of cable TV quality, and digital quality measurement for each service is required. However, spectrum analyzer can be used to analyze digital signal in CATV network. However, this equipment is expensive and bulky, which is very inconvenient for workers who need to secure mobility for network maintenance.

In order to solve this problem, the present invention aims to implement measurement equipment for installation and troubleshooting of DOCSIS standard cable modem as well as section-by-section quality analysis of a bidirectional CATV transmission network. In addition, the present invention implements a simple and low-cost measuring instrument using a cable modem unit, and the implemented instrument is connected to a CMTS (Cable Modem Termination System) and digital transmission status and service of a network using a CATV network. It should be possible to determine the cause of disability quickly and accurately.

Claims (21)

In measuring and analyzing the up and down signals in the CATV network, the cable modem unit (1) for measuring the main elements of the up and down signals, the input means (6) for inputting the user's measurement requirements, and the input measurement items A display means (3) capable of displaying measurement results, a power supply means (4) for supplying power for driving the instrument, and a cable modem unit (1) and a control means (2) for data communication during the entire measurement process. Measuring device comprising a communication means (7), a control unit (2) to enable all signal transmission and control through the cable modem unit, input means, display means, power supply means, communication means, etc. in the entire measurement process 2. The cable modem measuring instrument according to claim 1, wherein an operation state display means (11) for displaying a state where the cable modem portion (1) is connected to the network is attached. The cable modem measuring apparatus according to claim 1, wherein the cable modem measuring apparatus is serial communication (Serial) as a communication means (7) connecting the console terminal of the cable modem unit (1) and the control unit (2). The cable modem measuring instrument according to claim 1, characterized in that the communication means (7) connecting the cable modem unit (1) and the control unit (2) is Ethernet. The cable modem meter according to claim 1, characterized in that it is a universal serial bus (USB) as a communication means (7) connecting the cable modem unit (1) and the control unit (2). The cable modem measuring apparatus according to claim 1, wherein the cable modem unit is a PCI bus (PCI) as a communication means (7) connecting the cable modem unit (1) and the control unit (2). Cable modem measuring instrument according to claim 1, characterized in that the electrical line is directly connected to at least one terminal of the cable modem control means (9). The cable modem meter according to claim 1, wherein a rechargeable battery is used as a power supply means. The cable modem meter according to claim 1, wherein an AC power source is used as the power supply means. The cable modem measuring instrument according to claim 1, wherein an in-vehicle power supply means is used as the power supply means. According to claim 1, wherein the cable modem control means (9) is not integrated into a single ASIC chip, but at least one terminal (Lead) of the CPU chip in the case of being composed of a MAC (Media Access Control) chip, a CPU chip and a physical layer (PHY) Cable modem measuring instrument Cable modem measuring instrument according to claim 1, characterized in that it is a liquid crystal display (LCD) as a display means (7) connected to the control means (2). Cable modem measuring instrument according to claim 1, characterized in that the display means (7) connected to the control means (2) is an LED (Light Emitting Diode). Cable modem measuring instrument according to claim 1, characterized in that it is a touch screen as an input means (6) connected to the control means (2). Cable modem measuring instrument according to claim 1, characterized in that it is a mechanical switch (Switch) to the input means (6) connected to the control means (2) In measuring and analyzing the up and down signals in the CATV network, the cable modem unit (1) for measuring the main elements of the up and down signals, the input means (6) for inputting the user's measurement requirements, and the input measurement items A display means (3) capable of displaying measurement results, an output means (8) for moving the measurement results stored in the storage means to the outside of the instrument, a power supply means (4) for supplying power for driving the instrument, Communication means (7) which enables the cable modem unit (1) and the control unit (2) to perform data communication in the whole measurement process, cable modem unit, input means, output means, display means, power supply means, communication means, etc. in the whole measurement process Instrument, characterized in that consisting of a control unit (2) to enable all signal transmission and control through. Cable modem meter as claimed in claim 16, characterized in that it has a serial interface with an output means (8) connected to the control means (2). Cable modem measuring instrument according to claim 16, characterized by a universal serial bus (USB) as an output means (8) connected to the control means (2). The cable modem measuring instrument according to claim 16, wherein the printer is used as an output means (8) connected to the control means (2). In measuring and analyzing the up and down signals in the CATV network, the cable modem unit (1) for measuring the main elements of the up and down signals, the input means (6) for inputting the user's measurement requirements, and the input measurement items A display means (3) capable of displaying measurement results, a storage means (5) for storing S / W such as a measurement result or an OS used in the control means, and a measurement result stored in the storage means to be moved out of the instrument Output means (8), power supply means (4) for supplying power for driving the instrument, communication means (7) for the cable modem unit (1) and the control means (2) to allow data communication in the entire process of measurement, Characterized in that it consists of a control unit (2) to enable all signal transmission and control through the cable modem unit, input means, output means, display means, power supply means, storage means, communication means, etc. during the entire measurement process Instrumental. A cable modem measuring instrument according to claim 20, wherein a semiconductor memory element is used as the storage means (5) for storing the measurement result or the S / W required for control.