CDMA phones and all about standard SDMA
CDMA 2000-CDMA2000 is a further development of the standard 2 generation cdmaOne. The further development of cdmaOne was to become IS-95C, and this designation is very often used by manufacturers. The official update of the standard developed by Qualcomm and approved by the ITU (International Telecommunication Union) is cdma2000. Lucent Technologies documents the designation IS-2000. Finally, the International Telecommunication Union (ITU) selected from ten proposed projects five radio interfaces of the third generation IMT-2000 (International Mobile Telecommunications System - 2000 - International Mobile Telecommunications System - 2000), among them - IMT-MC (Multi Carrier), which represents is a modification of the cdma2000 multi-frequency system, which provides backward compatibility with cdmaOne standard equipment (IS-95). Another one of the five IMT-2000 standards - IMT-DS (Direct Spread) - is based on W-CDMA projects and is taken as the basis for the European UMTS system. At the beginning of 2003, out of 127 million CDMA users, almost 15 million used cdma2000 technology. During the first seven months of 2002, 11 CDMA2000 networks were launched in Asia and America and the total number of these networks was 18. This is 99% of the 3G market, IMT-MC had 14.8 million subscribers, UMTS - 0.13 million . However, it is worth noting that the cdma2000 1X implemented phase is still not a full-fledged 3G, because it does not reach the required two megabits. 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 applied. And the second was later named 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 meant by 3G IMT-MC. The 1x EV-DO standard was adopted by TIA in October 2000 and provides for the following scheme of operation: the device simultaneously searches for 1x and 1X EV networks, transmits data using 1X EV, and voices - using 1x. The 1X EV-DV standard is fully compliant with all 3G requirements. Now about the CDMA-450. It should be noted that the standards of the cdma2000 family do not require the organization of a separate frequency band and, during 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.
Cell phones cdma- A CDMA cell phone is a mobile communication device that uses a combination of radio transmissions and traditional telephone switching for telephone communications in the territory (coverage area) consisting of “cells” surrounding base stations of a cellular network. Currently, cellular communication is the most common of all types of mobile communication, therefore, a mobile phone is usually called a mobile phone, although in addition to cellular phones, radio telephones, satellite telephones and trunking communication devices are also mobile phones.
Phones cdma - phones of standard CDMA.
1X EV-DO is the development phase of the CDMA2000 1x mobile standard. EV-DO is short for EVolution Data Only. In contrast to EV-DV (EVolution Data Voice), only the data interface was evolved, and voice transmission 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 the operator of CDMA communications in Ukraine.
FDMA- (eng. Frequency Division Multiple Access) is a method of using radio frequencies, when only one subscriber is in the same frequency band, different subscribers use different frequencies within the cell. It is an application of frequency multiplexing (FDM) in radio communications. Therefore, until the initial request is completed, the channel is closed to other communication sessions. Full Duplex FDMA transmission requires two channels, one for transmission and the other for receiving. FDMA was used in the first generation (1G) analog communication and this principle is implemented in the standards AMPS, N-AMPS, NMT, ETACS (American standard).
WCDMA-Wideband Code Division Multiple Access (Broadband CDMA) is a radio interface technology chosen by most cellular operators to provide broadband radio access to support 3G services. The technology is optimized to provide high-speed multimedia services such as video, Internet access and video conferencing; provides access speeds of up to 2 Mbps at short distances and 384 Kbps at long distances with full mobility. These data rates require a wide bandwidth, so the WCDMA bandwidth is 5 MHz. The technology can be added to existing GSM and PDC networks, which makes the WCDMA standard the most promising in terms of network resource utilization and global compatibility.
SMS-GATEWAY-SMS Gateway is a system that allows subscribers of operators of various standards (GSM, CDMA, DAMPS) to communicate with each other through SMS-service without any obstacles.
TD-SCDMA - (English Time Division - Synchronous Code Division Multiple Access) is a Chinese standard for third-generation mobile networks. Designed to avoid outsourcing for the use of proprietary CDMA2000 and WCDMA technologies.
cdma router- SDMA router
Cingular Wireless- Cingular Wireless, LLC, headquartered in Atlanta, Georgia, USA, is the largest cellular operator in the United States with more than 58.7 million subscribers. The company has the largest digital data and voice network in the United States. Cingular, in its current 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 analogue NMT-450 and AMPS. The channel bandwidth is 300 kHz, the frequency division of the FDMA channels is the same as in AMPS. Additionally, time division of TDMA channels is used, as in GSM and in CDMA2000 1X EV-DO, only 3 timeslots (in GSM - 8 timeslots). In fact, a continuation of the development of the American DAMPS standard was the European GSM standard. Possibility of automatic roaming and SMS. The possibility of operating mobile devices in both digital and analog modes. If the subscriber with the analog network AMPS telephone falls into the digital one - DAMPS, analog channels are allocated for it to work. However, in this case, the advantages of digital communication are not available to him. This standard plays GSM in the ability to freely change outdated phones to new ones and transfer the old number to a new phone. In GSM, this is done by changing the SIM card; in DAMPS, this will have to be done in a special service center of the telecom operator. But the update of models in this sector is accelerating every day, as well as on 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.
is 95 cdma- IS-95 / cdmaOne (on the basis of which domestic OTUs were developed, in particular), was originally developed and developed as a mobile standard and is replete with reference to the word "mobile". Therefore, it is not easy to stop the "running buffalo" in terms of the "fixed plane" type. What to 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 imperceptible for the subscriber switching control when the subscriber moves between cells (the so-called "soft" switching or soft hand-off), which is so appreciated by the companies-operators and subscribers.
SMS-SMS (short message service is a short message service) is a system that allows you to send and receive text messages using a cell phone. * With the help of SMS, you can conduct a kind of correspondence, something resembling a pager. * You can send a message to the phone turned off / out of service. As soon as your addressee gets in touch, he will receive your message. * You can send a message to the subscriber who is currently busy talking. * With the help of the SMS delivery confirmation service, you can catch the moment when the subscriber has reached the connection. * Using the advanced SMS option, called EMS, send / receive call melodies, icons, and more. * You can subscribe to newsletters with the exchange rate, weather, etc. SMS technology is supported by major cellular networks (GSM, NMT, D-AMPS, CDMA). You can also send SMS messages to phones from the Internet and other networks (paging, fidonet, x.25, etc.), using special programs, universal sms-forms, as well as directly gateways of mobile operators.
cdma news- cdma news.
Wi-Fi- (pronounced as [Wi-Fi], abbr. From the English. Wireless Fidelity is a standard for equipment for broadband radio communications designed for the organization of local wireless networks Wireless LAN. Installing such networks is recommended where cable system deployment is impossible or economically Thanks to the handover function, users can move between access points in the territory of Wi-Fi network coverage without disconnecting. Developed by the Wi-Fi Alliance consortium based on IEEE 802.11 standards. Wired internet on the beach Mobile devices (PDAs and laptops) equipped with Wi-Fi client receiving and transmitting 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 gaining access to Internet resources via a mobile phone only, without resorting to a computer and / or modem. In essence, 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 mobile phone screen could display the variety of information as the computer display, then WAP would be no different from the display of 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 kept to the necessary minimum.
GPS-NAVSTAR GPS (English Navigation Satellite Time and Ranging, Global Positioning System - Measuring the range and time of the navigation satellite, Global Positioning System) - satellite navigation system, often referred to as GPS. It allows you to determine the location and speed of objects anywhere in the Earth (including the circumpolar regions), in almost any weather, also in outer space at a distance of up to 100 thousand km from the Earth's surface. The system is developed, implemented and operated by the US Department of Defense (US Department of Defense).
CDMA modem - CDMA modem.
Verizon Wireless is the second largest cellular operator in the United States. As of April 2006, the size of the company's subscriber base was 56.7 million customers, and the coverage area was the widest in the US cellular market. Registered in New Jersey, the company is a joint venture of Verizon Communications and the Vodafone Group, with a shareholding of 55% and 45%, respectively.
UMTS- UMTS (Universal Mobile Telecommunications Systems) is the third generation of mobile telephony, in the medium term it will replace the existing GSM systems. UMTS provides two main components: a radio network and a carrier network. The radio network consists of mobile equipment and a base station, between which the data transfer is switched. The carrier network, in turn, connects the base stations with each other, and also creates connections to the ISDN network and the Internet. With a much higher bandwidth (5 MHz) than GSM (200 kHz) and using the CDMA (Code Division Multiple Access) method for transmission, it becomes possible to transfer any type of information (multimedia applications, Internet download, video and audio) at high ( 2 Mbit / s transfer rates. 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 transmit 1-2 video source in real time with full resolution and acceptable quality. An interesting feature about UMTS is not only that UMTS has a very high transmitting capacity, but also that it also supports various transmission protocols, such as TCP / IP, in combination with mobility.
EDGE-EDGE (Enhanced Data Rates for GSM Evolution) is a digital technology for mobile communications that 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 the capabilities of the GSM network (to support EDGE in the GSM network, certain modifications and improvements are required). On the basis of EDGE can work: ECSD - accelerated internet access via CSD, EHSCSD - accelerated internet access via HSCSD, EGPRS - accelerated internet access via GPRS. EDGE was introduced to the world in 2003, initially in North America.
SIM-Subscriber Identification Module) - subscriber identification module used in mobile communications. Sim card (enlarged) Sim card (enlarged) SIM-cards are used mainly 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 to store identification information about the account, which allows the subscriber to easily and quickly change cellular devices without changing his account by simply moving his SIM card to another phone. Whereas, in cellular phones of networks that do not use SIM cards (AMPS, NAMPS, DAMPS, NMT-450), this information is stored in its internal memory and a change in the phone’s subscriber, while maintaining the account, can only be produced by reprogramming the phone. What is usually done only by the employee of the cellular operator, in the office of the operator and for an additional fee. The SIM card can also store some additional information, for example, the subscriber's phonebook, lists of incoming / outgoing phone numbers, text of SMS messages, SIM-Info, ... The SIM card contains a memory chip that supports encryption. One SIM card can be assigned several phone numbers recorded in the HLR of a cellular network switch. But this possibility is not used by any of the Russian mobile operators. The SIM card is installed in the SIM holder of a cell phone, which in modern cell phones is usually located under the battery. The location of the SIM-holder under the battery does not allow to install / remove the SIM-card when the phone power is on. The first SIM cards were the size of a credit card, but with the minimization of cell phones, a smaller new standard was adopted.
|Start of development||1970||1980||1985||1990||<2000||2000|
|Services||analog standard, synchronous data transfer at speeds up to 9.6 kbps||digital standard, support for short messages (SMS)||high capacity packet data||even more capacity, speeds up to 2 Mbps||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 Mbit / s||1 Gbps|
|Standards||AMPS, TACS, NMT||TDMA, CDMA, GSM, PDC||GPRS, EDGE, 1xRTT||WCDMA, CDMA2000, UMTS||HSDPA||uniform standard|
|Network||PSTN||PSTN||PSTN, packet data network||packet data network||packet data network||the Internet|