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CDMA phones and everything about the SDMA standard

CDMA 2000-CDMA2000 is the further development of the 2nd generation cdmaOne standard. Further development of cdmaOne was to become IS-95C, and it is this designation that is often used by manufacturers. The official update of the standard developed by Qualcomm and approved by the ITU (International Telecommunication Union) is cdma2000. In the documents of Lucent Technologies there is the designation IS-2000. Finally, the International Telecommunication Union (ITU) selected from the ten proposed projects five radio interfaces of the third generation IMT-2000 (International Mobile Telecommunications System-2000), among them IMT-MC (Multi Carrier), which represents is a modification of the multi-frequency cdma2000 system, which provides backward compatibility with cdmaOne (IS-95) equipment. Another one of IMT-2000's five standards - IMT-DS (Direct Spread) - is built on the basis of W-CDMA projects and is taken as the basis of the European UMTS system. At the beginning of 2003, of the 127 million CDMA users, nearly 15 million used cdma2000 technology. During the first seven months of 2002, 11 CDMA2000 networks were launched in Asia and the Americas and the total number of these networks was 18. This is 99% of the 3G market, IMT-MC accounted for 14.8 million subscribers, UMTS - 0.13 million . However, it is worth noting that the realized phase of cdma2000 1X is still not a full-fledged 3G, because it does not reach the required two megabit. Therefore, it is often called 2.5G. Initially, cdma2000 (IMT-MC) was divided into two phases - 1X and 3X. It is to the first phase that the name IS-95C is used. And a second later called 1X EV (evolution), dividing it into two phases - cdma2000 1X EV-DO (data only) and cdma2000 1X EV-DV (data & voice). And it is the cdma2000 1X EV-DO standard that is implied by the 3G IMT-MC. The standard 1x EV-DO was adopted by the TIA in October 2000 and provides the following scheme of operation: the device simultaneously searches for 1x and 1X EV networks, transmits data using 1X EV, voice with 1x. The 1X EV-DV standard fully meets all 3G requirements. Now about CDMA-450. It should be noted that the standards of the cdma2000 family do not require the establishment of a separate frequency band and in the course of their evolutionary development from cdmaOne can be implemented in all frequency bands used by cellular mobile communication systems (450, 700, 800, 900, 1700, 1800, 1900, 2100 MHz ).

CDMA 450-CDMA at a frequency of 450 MHz.

Cellular telephones cdma- Cellular phone CDMA is a mobile communication device using a combination of radio transmission and traditional telephone switching for making telephone communications in the territory (coverage zone) consisting of "cells" surrounding the base stations of the cellular network. At present, cellular communication is the most widespread of all types of mobile communication, therefore, a mobile phone is usually called a mobile phone, although mobile phones besides cellular phones are also radiotelephones, satellite phones and trunking communication devices.

Cdma phones are CDMA standard phones.

1X EV-DO is the development phase of the CDMA2000 1x mobile standard. EV-DO - short for EVolution Data Only. Unlike EV-DV (EVolution Data Voice), only the data interface has undergone evolution, and voice transmission has remained completely identical with CDMA2000 1x and CDMA One (IS-95a / b). The data transfer rate in EV-DO reaches 2.4 Mbps.

CDMA Ukraine is a CDMA communications operator in Ukraine.

FDMA- Frequency division multiple access is a way of using radio frequencies when only one subscriber is in one frequency band, different users use different frequencies within a cell. It is the application of frequency multiplexing (FDM) in radio communication. Therefore, while the initial request is not completed, the channel is closed to other communication sessions. Full-duplex FDMA transmission requires two channels, one for transmission and another for receiving. FDMA was used in the first generation (1G) of analog communications and this principle is implemented in the AMPS, N-AMPS, NMT, ETACS (American standard) standards.

WCDMA-Wideband Code Division Multiple Access is a radio interface technology chosen by most cellular operators to provide broadband radio access in order to support 3G services. The technology is optimized to provide high-speed multimedia services such as video, Internet access and videoconferencing; provides access speeds of up to 2 Mbit / s for short distances and 384 kbps for large ones with full mobility. Such data rates require a wide bandwidth, so the WCDMA bandwidth is 5 MHz. The technology can be added to existing GSM and PDC networks, making the WCDMA standard the most promising in terms of network resources and global compatibility.

SMS-GATEWAY-SMS Gateway is a system that allows subscribers of operators of different standards (GSM, CDMA, DAMPS) to communicate seamlessly with each other via SMS-service.

TD-SCDMA (English Time Division - Synchronous Code Division Multiple Access) is the Chinese standard for third-generation mobile networks. Designed to avoid deductions for the use of proprietary technologies CDMA2000 and WCDMA.

cdma router- SDMA router

Cingular Wireless- Cingular Wireless, LLC, based in Atlanta, Georgia, USA is the largest mobile phone operator in the US with more than 58.7 million subscribers. The company has the largest digital network of data transmission and voice information in the US. Cingular, in its present form, was formed through mergers and acquisitions, and as a result of this - coupled with rapid technological changes in the field of wireless data transmission - Cingular manages networks using different data transmission standards. The most widely used of these is the GSM standard. In addition to GSM networks, Cingular manages GPRS data networks, as well as networks based on EDGE (Enhanced Data Rates for GSM Evolution).

D-AMPS-D-AMPS or Digital AMPS is a digital standard for mobile communications in the frequency range from 825 to 890 MHz. Features The capacity of cellular networks operating in DAMPS is lower than in fully digital systems (GSM, CDMA), but still significantly higher than in analog NMT-450 and AMPS. The bandwidth of the channel is 300 kHz, the frequency division of the FDMA channels is the same as in AMPS. The time division of TDMA channels, both in GSM and in CDMA2000 1X EV-DO, is used in addition, and only 3 timeslots (in GSM - 8 timeslots). In fact, the continuation of the development of the American standard DAMPS was the European standard GSM. Possibility of automatic roaming and SMS. The ability to operate mobile devices in both digital and analog modes. If the subscriber with the phone of the analog AMPS network falls into the digital one - DAMPS, analog channels are allocated to him for work. However, in this case, the advantages of digital communication are not available to him. This standard loses GSM in the ability to freely change the outdated phone models to new ones and transfer the old number to a new phone. In GSM, this is done by changing the SIM-card, in DAMPS it will have to be done in a special service center of the communication operator. But the update of models in this sector is accelerating with each passing day, as well as in the computer market. Recall that a cell phone has already been released in the form of a wristwatch with voice dialing.

CDMA system- SDMA system.

CDMA technology-sdma technology.

is 95 cdma-IS-95 / cdmaOne (on the basis of which domestic OTUs have been developed in particular), it was originally developed and developed as a standard for mobile communications and abounds with the mention of the word "mobile". Therefore, to stop the "running bison", in terms of the "fixed plane" type, is not easy. What can we say about his descendants and other broadband relatives such as W-CDMA and cdma2000. In addition, it is the CDMA technology that allows the most qualitative and inconspicuous switching for the subscriber when moving a subscriber between cells (so-called soft handoffs), which is so appreciated by operator companies and subscribers.

SMS-SMS (English Short Message Service) is a system that allows you to send and receive text messages using a cellular phone. * Using SMS, you can conduct a kind of correspondence, something that resembles a pager. * You can send a message to the off / out of the coverage area of ​​the phone. Once your recipient is online, he will receive your message. * You can send a message to the subscriber who is currently busy with the conversation. * Using the service to confirm the delivery of an SMS message, you can catch the moment when the subscriber leaves for communication. * Using the extended version of SMS, called EMS, send / receive ringtones, icons and much more. * You can subscribe to mailings with the exchange rate, weather, etc. SMS technology is supported by the basic cellular networks (GSM, NMT, D-AMPS, CDMA). Also SMS messages to phones can be sent from the Internet and other networks (paging, fidonet, x.25, etc.), using special programs, universal sms forms, as well as directly gateways to mobile operators.

cdma news-cdma news.

Wi-Fi- (pronounced [wi-fi], abbreviated from English Wireless Fidelity is the standard for broadband radio equipment intended for the organization of local wireless LANs.The installation of such networks is recommended where the deployment of a cable system is impossible or economically Thanks to the handover function, users can move between access points over the Wi-Fi coverage area without breaking the connection, developed by the Wi-Fi Alliance consortium based on IEEE 802.11 standards. Wireless Internet at Besp Beach wired internet on the beach Mobile devices (PDAs and laptops) equipped with client Wi-Fi transmitting and receiving devices can connect to the local network and access the Internet through so-called access points or hotspots.

WAP- "wireless access protocol" is a means of accessing Internet resources through only a mobile phone, without resorting to the help of a computer and / or a modem. In fact, this is a technical standard that describes the way in which information from the Internet is transmitted to a mobile phone display. Theoretically, if the screen of a mobile phone could display that variety of information that the computer display, then WAP would not be different from displaying ordinary WEB-pages. But since the resolution of the display screen of a mobile phone is small, the display of WAP-sites is characterized by insufficient graphics and animation, and the amount of information is reduced to the required minimum.

GPS-NAVSTAR GPS (GPS) is a satellite navigation system, often referred to as GPS. Allows anywhere and the Earth (including subpolar areas), almost in any weather, also in outer space at a distance of up to 100 thousand km from the Earth's surface, to determine the location and speed of objects. The system is developed, implemented and operated by the US Department of Defense (English US Department of Defense).

CDMA modem - CDMA modem.

Verizon Wireless is the second largest mobile phone operator in the United States. As of April 2006, the company's subscriber base was 56.7 million customers, and the coverage area was the broadest in the US cellular market. Registered in New Jersey, the company is a joint venture between Verizon Communications and the Vodafone Group, with a 55% and 45% shareholding, respectively.

UMTS-UMTS ("Universal Mobile Telecommunications Systems") - the third generation of mobile telephony, will replace the current GSM systems in the medium term. UMTS provides two main components: a radio network and a carrier network. A radio network consists of mobile equipment and a base station, between which the data transmission is switched. The carrier network, in turn, connects the base stations to each other, and also creates connections to the ISDN network and the Internet. With a significantly larger bandwidth (5 MHz) than GSM (200 kHz) and using the CDMA (Code Division Multiple Access) method, it is possible to transmit information of any type (multimedia applications, downloads from the Internet, video and audio) at high ( 2 Mbps) of the transmission speed. This makes UMTS up to 30 times faster than ISDN (64 kbps) and up to 200 times faster than the GSM network (9.6 kbps). This allows you to send 1-2 sources of video in real time with full resolution and acceptable quality. An interesting feature about UMTS is not only that UMTS has very high transmitting capability, but also that it also supports various transmission protocols, such as TCP / IP, in combination with mobility.

EDGE- EDGE (English Enhanced Data rates for GSM Evolution) is a digital technology for mobile communications, which functions as an add-on over 2G and 2.5G (GPRS) networks. This technology works in TDMA and GSM networks. EDGE is an extension of GSM network capabilities (certain modifications and improvements are required to support EDGE in the GSM network). On the basis of EDGE can work: ECSD - accelerated access to the Internet via CSD, EHSCSD - accelerated Internet access via HSCSD, EGPRS - accelerated access to the Internet via GPRS. EDGE was introduced to the world in 2003, originally in North America.

SIM-card- Subscriber Identification Module) - subscriber identification module used in mobile communication. Sim card (increased) SIM card (increased) SIM cards are used primarily in GSM networks. The 3G network, a new generation of mobile networks based on GSM principles, also has its own identification card, called USIM. Subscriber cards are also sometimes used in networks such as CDMA / TDMA. The main function of the SIM card is the storage of identification information about the account, which allows the subscriber to easily and quickly change cell phones, without changing their account, simply by moving their SIM card to another phone. Whereas in cellular phones that do not use SIM-cards (AMPS, NAMPS, DAMPS, NMT-450), this information is stored in its internal memory and can be changed by the subscriber of the phone, with the account maintained, only by reprogramming the phone. What usually is done only by the employee of the cellular operator, at the operator's office and for an additional fee. Also, the SIM-card can store some additional information, for example, the subscriber's phone book, lists of incoming / outgoing phone numbers, text of SMS messages, SIM-Info, ... SIM-card contains a memory chip that supports encryption. One SIM card can be assigned several phone numbers recorded in the HLR of the cellular network switch. But none of the Russian mobile operators is using this feature. The SIM card is installed in the SIM-holder of a cellular phone, which in modern cellular phones is usually located under the battery. Location of the SIM-holder under the battery does not allow you to install / remove the SIM-card while the phone is on. The first SIM cards were the size of a credit card, but with the minimization of cell phones a new standard of a smaller size was adopted.

Generation 1G 2G 2.5G 3G 3.5G 4G
Start of development 1970 1980 1985 1990 <2000 2000
Implementation 1984 1991 1999 2002 2006-2007 2008-2010
Services analogue standard, synchronous data transfer with a speed of up to 9.6 kbps digital standard, support for short messages (SMS) high capacity, packet data transfer even greater capacity, speeds up to 2 Mbit / s increase the speed of third generation networks large capacity, IP-based network, multimedia support, speeds up to hundreds of megabits per second
Channel width 1.9 kbps 14.4 Kbps 384 kbps 2 Mbps 3-14 Mbps 1 Gbit / s
Standards AMPS, TACS, NMT TDMA, CDMA, GSM, PDC GPRS, EDGE, 1xRTT WCDMA, CDMA2000, UMTS HSDPA common standard
Net PSTN PSTN PSTN, packet data network packet data network packet data network the Internet