High-speed data transmission methods

Many emerging forces are driving markets towards network integration, factors such as cost reduction in initial investment, technical support and maintenance, the emergence of integrated applications that generate new demands on the network, the functionality and flexibility of architectures and the birth of standards in the industry lead to the integration of systems into a single structure. The convergence "payload" for example, allows the transmission of different types of data in the same communication format, this phenomenon leads to the physical unification of the network because different types of files can use the same architecture installed, the technologies previously developed for each format converge in a single application compatible with a single type of receiver device that handles defined protocols that allow interoperability. Thanks to this phenomenon, users no longer have to think about a telephone system to make their calls and a different one to connect to the Internet or watch TV; the dilemma today is to achieve an efficient communication method that allows access to all multimedia formats at fast access rates and at an affordable cost.

The development in data transmission currently revolves around the term "quick access", input that is basically given through cable modem, DSL (Digital Subscriber Line) and wireless networks.

It is a unit that connects a cable structure to an Ethernet network card in a PC. As the name implies, the function of this apparatus is to modulate "Mo" and demodulate "Dem" received signals. They can be analog or digital; Analog modems or dial-up modems are external or internal units that connect to a serial port on a computer at a maximum speed of 56 kbps and transmit via narrowband telephone lines. Digital units are specially designed to transmit information via co-axial cable (broadband media) at a speed ranging from 30 to 10 Mbps; they can also be internal or external drives. This system does not handle dedicated lines and users share the access channels to the network, that is, the bandwidth available to download or upload information on the network varies. The access speed is directly linked to the number of online users simultaneously.

Digital Subscriber Line DSL, is an access technology that uses a pair of copper lines, traditional telephone lines, to transmit data, voice and video over a dedicated digital network, between the user's modem and the network service provider (NSP) that uses a device known as DSLAM (Digital Subscriber Line Access Multiplexer). ) to transmit the information. This technology is permanently connected that avoids the congestion and loss of time generated by dial-up connections. One of the strengths of this technology is that the user can use the analog part of the line as a modem or fax while simultaneously using the data part for DSL access. There are several types of DSL technology because it uses different parts of the frequency spectrum to transmit, apart from analog voice signals, making it able to work in conjunction with standard POTS services, sharing the same pair of lines. The basic differences are in the symmetry and the speed of transmission achieved (see table 1). The types of DSL are:

1. ADSL: Asymmetric Digital Subscriber Line allows the transmission of data and voice signals over a pair of copper lines. It allows simultaneous use of the telephone and ADSL as it uses the frequency range of 0-4 KHz for traditional telephone and fax service (POTS) and the range of 38 KHz to 1.2 MHz for data transmission. It is ideal for browsing Intranet and Internet, VOD and remote access to LANs. The solutions for this type of connection can be developed under two modulation schemes CAP (Carrierless Amplitude Phase) or DMT (Discrete Multi-Tone).
1. R-ADSL: It is an ADSL line that automatically adapts the access speed to the conditions of the line, with this type of connection it is possible to connect on different lines at different speeds.
1. ADSL Lite: is a lower speed version of ADSL that eliminates the need for the service provider to install Splitters to generate the POTS. This simplifies installation and reduces costs for the NSP.
1. IDSL: ISDN Digital Subscriber Line, symmetrical connection (has the same speed both when downloading and uploading information on the network) restricted to data transmission only. It uses the ISDN modulation code 2B1Q (Two-Binary, One-Quaternary) , the advantage of this scheme is that it does not cause interference in the line known as Crosstalk, despite coexisting with T1 services.
1. HDSL: High Bit-Rate DSL, symmetrical connection that is developed in two or three pairs of linked lines making it ideal for connecting PBX systems, DLPs (Digital Local Loops), internet servers and networks.
1. SDSL: Single-Line DSL, Symmetrical connection that supports T1/E1 type transmissions over a pair of copper lines, despite its distance limitation, is capable of accommodating applications that require identical upload and download speeds such as video conferencing. For voice transmission, it is necessary to include another pair of lines. It uses the 2B1Q modulation scheme like the ISDN.
1. VDSL: Very High Bit-Rate DSL, it is the fastest of all connections using only a couple of copper lines, it is ideal for connections in homes since its maximum performance has great distance limitations.

They are LAN-like networks created as data transmission systems with the ability to provide access to networks regardless of the location of computers using radio waves (2.4 GHz ISM Band) instead of cable infrastructure. Currently, wireless networks have been implemented in vertical applications such as manufacturing facilities, warehouses and retail stores. The market with the greatest projection for this type of networks is expected to be facilities for health care, educational institutions and corporate spaces. The further development of them depends on the standardization formats that the industry manages to create. Currently this type of connection works under the 802.11 High Rate or 802.11b standard that supports transmissions at a rate greater than 11 Mbps. It uses the modulation codes BPSK (Binary Phase Shift Keying) to transmit at 1 Mbps and QPSK (Quadrature Phase Shift Keying) for transmissions from 2 Mbps onwards. The mode of operation is based on a wireless station equipped with a network interface card (NIC) and an access point that acts as a bridge between the unit and the wired network. The advantage of this type of connection is the combination of mobile access and flexibility in configuration, along with reduced maintenance costs as it requires a minimum of wiring and installations.