ofdm modem

The popularity of broadband has greatly changed our network life and made it more colorful. However, the various faults and problems that followed have made it impossible for many netizens who first came into contact with broadband. The failure of the broadband network is very different from that of the conventional Modem. This article takes the city of Shanghai where the author is located as an example to describe various common faults. Line Fault Th

whether the problem is resolved. If the problem persists, continue until the fault disappears. Layered Network diagnosis technology Physical Layer faults mainly occur when the physical connection mode of the device is correct, the connection cable is correct, and the configurations and operations of devices such as Modem, CSU, and DSU are correct. The best way to determine whether the physical connection of a vro port is intact is to use the show int

Early domestic ADSL line access are bridge mode, by ADSL modem and computer, in the computer to allocate fixed IP address, boot can access to the local terminal equipment into the Internet. However, when the user does not boot on the Internet, IP is not to be exploited, will cause the current increasingly scarce public network IP resources waste, so there has been a PPPoE dial-up ADSL access. PPPoE dial-up can enable the user on the power-on dial-up

difficulty in understanding SRP is in the case of a multifunctional class, which is not easy to understand the contradiction between versatility and single change. Let's take a look at a modem class example, modem has 4 functions: dial-up, hang up, send data, receive data: class　Modem　{ 　　　　 public　void　Dial(string　aPno)　{…} 　　　　 public　void　Hangup()　{…} 　　　　 p

an Ethernet gateway. # Exec/usr/sbin/pppd debug lock modem/dev/ttys0 115200 \ Asyncmap 20a0000 escape FF kdebug 0 $ local_ip: $ remote_ip \ Noipdefault netmask $ netmask defaultroute connect $ dialer_script Exec/usr/sbin/pppd debug lock modem/dev/ttys0 115200 \ Asyncmap 20a0000 escape FF kdebug 0 $ local_ip: $ remote_ip \ Noipdefault netmask $ netmask defaultroute connect $ dialer_script: (you can use man

dial-up Internet access To facilitate the management and maintenance of the ADSL Modem device during Internet access in the future, many manufacturers often set the "80" port of the ADSL Modem device to its backend Management port, however, if an attacker or hacker knows the default IP address of the ADSL Modem, the administrator password of the ADSL device may

ADSL is a very common broadband access method. However, since one user has only one ADSL account, how can we achieve multi-user sharing of ADSL? Here we will introduce the implementation method. ADSL is an affordable broadband access solution. Currently, it is billed on a monthly basis. if a user uses an account to access the Internet, it will be a bit uneconomical. How can one ADSL user access the Internet? The following are some experiences. Sharing principle: in view of the current mainstream

There are a variety of wireless Internet access methods. We often see wireless network interfaces and wireless network interfaces for wireless Internet access. For today's wireless trends, the wireless access of infrared seems a little retro. It cannot be said that it has been out of the stage, at least in terms of choice, it has gradually been forgotten by everyone. Next we will introduce a wireless Internet access solution through infrared rays. This method is based on GPRS traffic to access t

can not meet the growing business needs, so IEEE in 1999 has launched a 802.11b, 802.11a two standards. And at the end of 2001 through the 802.11G Trial hybrid scheme, which can achieve 54Mbps data rates in the 2.4GHz band, and compatible with the 802.11B standard. 802.11b work in 2.4GHz ISM (industrial, technical, medical) band, using direct series spread spectrum and complement keying, can support 5.5Mbps and 11Mbps two kinds of speed, can with the rate of 1Mbps and 2Mbps 802.11 DSSS (direct

routers on this side of the WAN port are plugged in, but not connected to the modem, LAN access is not connected to the wall modules. 2, network cable connectivity failure, mainly the quality of the network cable is poor, or the line sequence is not correct. Modem access to the router, usually the modem distance from the router is not far, as long as the line s

At present, ADSL permeate every corner of our lives, whether it is enterprises, Internet cafes, or home users using ADSL to access the Internet, usually, an ADSL line can only support one computer to access the Internet, however, after using a networking device, you can implement an ADSL line to support Internet access shared by multiple computers. Generally, devices that implement the shared networking of ADSL include ADSL Modem, Broadband Router, an

wireless router, we have to do the physical connection operations related to the wireless router: First of all, the ADSL modem device is connected to the WAN port of the wireless router, and then the common twisted pair connects the LAN port of the wireless router with the normal workstation. After completing the physical connection operation, we go to the Windows system interface of the normal workstation and open the system's TCP/IP property Setti

Shanghai Bell Company's Cablelink Cable modem system provides high-speed asymmetric data communication services to users through the fiber coaxial hybrid network. The asymmetry of its connections requires high-speed communications in one direction, such as network browsing, Internet file transfer, and ideally in the opposite direction with a lower-rate delivery service. The TDMA access method used in Cablelink 2000 system can make the system more flex

Previously I wrote about the application of CP in OFDM, mainly to record the idea of 1.0 stars. Today I suddenly want to write something about channel characteristics. The reasons are as follows: 1) the status of the channel in simulation is unquestionable. Simulation under different channels is the focus of many topics, and it is almost unknown. 2) Since there is no entry point, we can only start with the simplest channel prediction. Of course we wil

ADSL is an affordable broadband access solution. Currently, it is billed in monthly subscription mode. If a user uses an account to access the Internet, it will be a bit uneconomical. How can one ADSL user access the Internet? The following are some experiences.　　 Sharing principle　　 In view of the current mainstream Ethernet interfaces, the external ADSL Modem has built-in routers and routing functions, and also has a large-capacity ROM chip (includi

[Plain]/** This program is improved from minimad. For more details, see minimad. c.** MyMinimad. c, 2008/09/17, SiChuan University, China** Compilation: gcc MyMinimad. c-o MyMinimad-lmad-g-Wall* Run:./MyMinimad filename.pdf*/# Include # Include # Include # Include # Include # Include # Include # Include # Include # Include Struct buffer {Unsigned char const * start;Unsigned long length;};Static int sfd;/* sound device descriptor */Static int decode (unsigned char const *, unsigned long );Int mai

Previously I wrote about the application of CP in OFDM, mainly to record the idea of 1.0 stars. Today I suddenly want to write something about channel characteristics. The reasons are as follows: 1) the status of the channel in simulation is unquestionable. Simulation under different channels is the focus of many topics, and it is almost unknown. 2) Since there is no entry point, we can only start with the simplest channel prediction. Of course we wil

Previously I wrote about the application of CP in OFDM, mainly to record the idea of 1.0 stars. Today I suddenly want to write something about channel characteristics. The reasons are as follows: 1) the status of the channel in simulation is unquestionable. Simulation under different channels is the focus of many topics, and it is almost unknown. 2) Since there is no entry point, we can only start with the simplest channel prediction. Of course we wil

Introduction to Vim code folding commands 1. Code folding through OFDM: set OFDM = xxx There are 6 Ways to fold: | Fold-manual | manual Folds are created manually.| Fold-indent | indent Lines with equal indent form a fold.| Fold-expr | expr 'foldexpr' gives the fold level of a line.| Fold-marker | marker Markers are used to specify folds.| Fold-syntax | syntax Syntax highlighting items specify folds.| Fold-

to 108Mbps, even up to 500Mbps. Thanks to Mimo OFDM, which combines MIMO with OFDM (Orthogonal Frequency Division multiplexing) technology, this technology not only improves the quality of wireless transmission, but also greatly improves the transmission rate. Application prospects: 802.11N will allow WLAN transmission rate of 10 times times the current rate of transmission, and can support high-quality v