Cellular Telecommunication – GSM, CDMA

From my last post, I have written about telecommunication in general. Here I will write more about cellular telecommunication and its technologies particularly GSM and CDMA. Both are 2G technology.

Most people now associate telecommunication with modern technologies that provide mobile communications to users both in the form of voice and data transmissions. There are a number of different standards that telecommunication companies use to provide cellular services.

Cellular telecommunication was conducted over analog system that transmits waveforms which can degrade over long distances. Because of that, cellular telecommunication has transformed to digital converting the signals into groups of numbers that could not be broken down over time and distance. As a result of this digital transformation, cellular telecommunications are based on many different standards. Phones and systems that operate on the same standard can usually work with each other.

The most popular of the digital standards are Global System for Mobile Communication (GSM) and Code Division Multiple Access (CDMA). GSM is the standard used in much of the world. In Malaysia, GSM is most common, while CDMA and PHS (PHS) mobile phone is also very popular.

In terms of data transfer speed, both technologies continue to rapidly leapfrog one another. Both provide “3G” standards or 3rd generation technologies. CDMA2000 is CMDA’s answer to need for speed. GSM’s answer is EDGE (Enhanced Data Rates for GSM Evolution) with added technologies that include UMTS (Universal Mobile Telephone Standard) and HSDPA (High Speed Downlink Packet Access) This technology is also known as W-CDMA, but incompatible with CDMA networks.

GSM phones uses SIM cards that allow phones to be instantly activated, interchanged, swapped out and upgraded, all without carrier intervention. The SIM itself in tied to network, rather than the actual phone. CDMA carriers on the other hand require proprietary handsets that are linked to one carrier only. When upgrading a CDMA phone, the carrier must deactivate the old phone then activate the new one and the old phone becomes useless.


Getting to Know Telecommunication

It has been almost 6 weeks already since my job attachment here in a mobile telecommunication company. As a CISCO certified person, I am appointed as an IT technician who troubleshoots pc and networks around Sabah region. During my stay, I started to speculate on the things they do here. How do they provide services to subscribers located around the region? What technologies do they use to provide these services? How do wireless broadband work? What is telecommunication? All these questions started to build up so I took the effort to conduct my own research on the subject.

Although telecommunication is a totally different field from my IT/networking background, there are still some similarities. For one which is the most obvious, the company I’m at uses CISCO devices for their interconnection too. This is because they also provide data transmission services other than voice transmission. So I am going to spend some time here to explain briefly what I have researched so far. Good stuff…

Today telecommunication is all about providing wireless connection to wide range of areas around the globe with great transmission speeds. Although fixed lines are still widely used, mobile communication has grown rapidly that led to the significant decline in fixed network subscriptions. This leads me to believe that being in the mobile industry is and will be secure for a very long time. But nevertheless, both fixed lines and mobile communication are both extension to the word telecommunication; transmission of messages over significant distances for the purpose of communication. So how did it all began?

Earlier signs of telecommunication started when the electrical telegraph was invented in the 1840s. A telegraph is used to communicate over long distance by using Morse code. Then came the conventional telephone in 1876 which is now in use worldwide. The invention of radio in the late 19th century and television in the early 20th century has played an important role in wireless communication. At that time, only voice was transmitted through the transmission medium. Now in the digital age, we have packet switching (transmission of data packets) which then made the Internet possible.

Mobile Telecommunication Company for example Maxis, Celcom and Digi provide communication services to mobile devices which may move around freely unlike Telekom who provides fixed line network. These services include wireless telephony and broadband internet services. To be able to provides these services, wireless standards have to be used. These standards are like GSM, CDMA, UMTS and WiMAX. More on these technologies in my next post.