Monday, March 27, 2017

Definition of GSM and CDMA

Definition of GSM and CDMA

Definition of GSM and CDMA
GSM (Global System for Mobile Communications) is one of the standard wireless communication system (wireless) are bersifatterbuka. GSM phones are used by more than one billion people in more than 200 negara.Banyaknya GSM standard makes international roaming very common with "persetujuanroaming" between mobile phone operators. There is also another sense of the Global System for mobilecommunication (GSM) is a global standard for digital mobile communications. GSM adalahnama of a standardization group that was formed in Europe in 1982 for common standards menciptakansebuah cellular mobile phone in Europe that operates on frekuensi900MHz area. GSM is currently widely used in countries in many different dunia.GSM with previous technology in signaling and "channel" talks are digital, which means iadipandang as a mobile phone system second generation (2G). GSM is an open standard which is currently developed by the 3GPP.

Code division multiple access (CDMA) is a form of multiplexing (not a modulation scheme) and a metodeakses in bersamayangmembagi channel is not based on time (like padaTDMA) or frequency (as padaFDMA), but instead encodes the data with a special code yangdiasosiasikan with each channel existing and use sifatinterferensikonstruktif properties of the special codes to perform a mobile phone pemultipleksan.Dalam teknologitelekomunikasi development primarily related to third generation (3G) CDMA become the technology of choice a future
, CDMA also refers to digital cellular systems menggunakanskema this multiple access, such as those pioneered olehQualcomm.CDMA is a military technology that was first used in the Second World padaPerang by British allies to thwart Germany mengganggutransmisi them. Allies decided to transmit not only on satufrekuensi, but at some frequencies, make it difficult for Germany to menangkapsinyal that lengkap.Sejak that CDMA is used in many communications systems, including padaGlobal Positioning System (GPS) and the transport logistics satelitOmniTRACSuntuk system. The last system was designed and developed by Qualcomm, and became the forerunner of which help engineers to menemukanSoft Handoff Qualcomm and fast power control, the technology needed to make CDMA praktisdan efficient for terrestrial mobile communications.


The difference between GSM and CDMA

The fundamental difference from CDMA technology is modulasinya.Modulasi CDMA system is a combination of FDMA (Frequency Division Multiple Access) and TDMA (Time Division Multiple Access). In FDMA technology, one frequency channel serving one circuit at a time, whereas in TDMA, 1 channel frequencies used by multiple users in a manner different time slots. In the CDMA multiple users can be served at the same time and the same frequency, where no distinction between each other on their coding system, so the use of spectrum CDMA technology is very efisien.Kelebihan of CDMA include voice and data quality, price or tariffs cheaper, smaller investment, and communication security (not easily intercepted).

GSM and GPRS technology content is terlibas the limitations CDMAkarena be wide data and multimedia applications on GSM-based technology GSM.Kelebihan technology in Indonesia is widely danroaming yanga very large home both in the country and even around the world, while CDMA TelkomFlexi still very limited. There are two types of CDMA mobile phones without the card so that the call number should be programmed by the dispatcher is concerned, but there is also a CDMA phone that is equipped with UIM (User Identification Module Removal) or in terms of GSM known as SIMCard.Dari aspects of both GSM and CDMA technology is teknologiseluler standard digital GSM only difference is developed by European countries and are 'open source', while CDMA from the US and Japan. Which perludiperhatikan that GSM and CDMA technologies coming from different lines, so that the development of 2.5G and 3G generation to the next will be different.


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