Mobile and Cell Phone Technologies (CDMA, GSM , 3G, 4G)

Mobile Phone

It is also known as Cellular Phone. A mobile phone is that can make and receive telephone calls over a radio link (satellite) while moving around a wide geographical area.

It does so by connecting to a cellular network provided by a mobile operator allowed accessed to public telephone network.

Cell Phone Technologies

* CDMA -

Code Division Multiple Access (CDMA) is a digital cellular technology used for mobile communication. CDMA is the base on which access methods such as cdmaOne, CDMA2000, and WCDMA are built. CDMA cellular systems are deemed superior to FDMA and TDMA, which is why CDMA plays a critical role in building efficient, robust, and secure radio communication systems.

A Simple Analogy

Let’s take a simple analogy to understand the concept of CDMA. Assume we have a few students gathered in a classroom who would like to talk to each other simultaneously. Nothing would be audible if everyone starts speaking at the same time. Either they must take turns to speak or use different languages to communicate.

The second option is quite similar to CDMA — students speaking the same language can understand each other, while other languages are perceived as noise and rejected. Similarly, in radio CDMA, each group of users is given a shared code. Many codes occupy the same channel, but only those users associated with a particular code can communicate.

Salient Features of CDMA

CDMA, which is based on the spread spectrum technique has following salient features −

·        In CDMA, every channel uses the full available spectrum.

·        Individual conversations are encoded with a pseudo-random digital sequence and then transmitted using a wide frequency range.

·        CDMA consistently provides better capacity for voice and data communications, allowing more subscribers to connect at any given time.

·        CDMA is the common platform on which 3G technologies are built. For 3G, CDMA uses 1x EV-DO and EV-DV

* GSM -

Global System for Mobile Communication is a standard developed by European Telecom Standard Institute (ETSI). To describe protocols for second generation (2G) digital cellular network used by mobile phones.

It was developed first in Finland in 1991 as of 2014 it has become the default global standard for mobile application communication with over 90% market share. 2G is developed as a replacement for 1G.

Features - Text, Fax, 2D, Sms

* GSM provide voice and unlimited data service. It uses digital modulation for improving audio quality.

* Digital AMPS & CDMA were 2G systems.

Drawbacks - 

1. Circuit switching connection-oriented technology where the end systems are dedicated to the entire calls.

2. Insufficiency in uses of Land breadth and resources. The GSM enabled system do not support high data rates.

3. Enable to handle high data rate such as video, it reduces the range of sound and it weaks the digital signal.

4. Weaker the digital signal.

* 3G -

3G stands for Third Generation. It comes after 2G with high data transfer. To meet drawing demand in network capacity rates required for high-speed data transfer and multimedia application 3G standard start evolving.

It is based on Internation Telecommunication Union (ITU) family of a standard. 3G technology enables network operators to offer users a wide range of more advanced services. It includes the service like wireless voice, telephonic video calls, and broadband wireless data.
The data are sent through the technology called Packet Switching.

Features-
1. Phone calls,
2. FAX
3. Send/ Receive large email messages
4. High-Speed web
5. Navigation
6. Video Conferencing
7. TC streaming

* It gives the speed of 200kbps
* It takes minimum seconds to download a video song

Advantage -

• new radio spectrum
• more bandwidth, security, reliability
• high data rates
• rich multimedia services
• always online devices

Disadvantages-

• expensive
• numerous differences in the terms of a license
• challenge to build necessary 3G infrastructure
• expense of 3G phone
• large cell phones

*4G -

4G is a short end name for the 4th Generation of the wireless data transmission network setup by the mobile phone industry. In order to offer more bandwidth and greater speed.

4G is the 4th Generation of mobile telecommunication technology succeeding 3G and preceding 5G.

Mobile WiMax standard first used in South Korea in 2007 and first release (long term evolution) LTE standard.

What are the speed?
4G gives 24 to 30 Mbps which is likely to give you 6 to 15 Mbps in peak time.
4G will offer as high as 60 Mbps when 3G is around 1.5 Mbps

Why we need 4G?

• better quality
• wide variety of services
• used OFDMA technology (orthogonal frequency-division multiple access)
• high speed teleworking
• real time financial information

Advantages-

• Quickly download files over a wireless network
• extremely high video quality
• easily access internet
• social network streaming, video calling etc
• higher bandwidth

Drawbacks-

• new components will be added in cell towers
• higher data prices
• consumer is forces to buy a new 4G device to support 4G

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