The tablet revolution

The transition from netbook to tablet happened so fast that some of us are still trying to figure all of it out. Apple has made its mark on the IT landscape by introducing the iPad which is a revolutionary piece of equipment. Along with the introduction of the Google's Android OS, the tablet market took off with companies such as Samsung becoming major competitors of Apple.

Figure 3.9 Tablet computer

Mobile device connectivity

The modern day mobile device is constantly connected to the rest of the world. In the past, the connection between two mobile phones was initiated only when one party called the other. Today however, modern smart phones and tablets stay continuously connected with the rest of the world through the WWW using a variety of connectivity technologies.

Analogue Cellular Networks (1G)

Analogue cellular networks were the first generation (1G) of wireless communication technologies. These were called analogue cellular networks as the voice was not digitally encoded but was modulated to a high frequency during the conversation. 1G speeds vary between that of a 28k modem(28kbit/s) and 56k modem(56kbit/s)resulting in actual download speeds of 2.9KBytes/s to 5.6KBytes/s.

Figure 3.10 Cellular network

GSM - Global System for Mobile Communications (2G)

GSM is a cellular network which constantly searches for and connects with cells (transmission towers equipped with antennas) in the immediate vicinity. This dependency on cells gave rise to the term "cellular phone" which is synonymous with mobile phones. The unique feature of GSM was the introduction of subscriber identity module or SIM card which allowed the user to retain his/her information and phonebook while switching handsets.

Figure 3.11 SIM card

This new technology sparked the modern day trend of changing handsets to keep up-to-date with the latest technology. GSM networks commonly operate in the 900 MHz or 1800 MHz bands. The frequency is then divided up into eight timeslots to be shared by concurrent users. The combined channel data rate for all 8 channels is 270.833kbit/s.

GPRS - General packet radio service (2.5G)

GPRS is a packet oriented mobile data service which works on GSM or 3G. When combined with GSM networks, GPRS is called a 2.5G technology. Even though GPRS is considered a best-effort service where the quality of service is dependent on the number of users sharing the data channel, this technology was the first of its kind which allowed users to affordably connect to the internet through their mobile devices. Typical GPRS data rates are around 56-114kbit/s but vary largely according to the usage of the channel. GPRS was later enhanced with enhanced data rates for GSM evolution (EDGE) which is also known as Enhanced GPRS (EGPRS). With peak pit rates of up to 1Mbit/s and typical bit-rates of 400kbit/s this technology was seen as the precursor to 3G.

3G - 3^rd Generation Mobile Telecommunications

3G revolutionised the way mobile phones and devices could be used to communicate and access information. With larger bandwidths, 3G supports voice telephone, mobile Internet access, video calls and mobile TV in mobile environments. Although the standard for 3G dictates that peak data rates of at least 200kbit/s (about 0.2 Mbit/s) should be maintained in 3G networks, most modern 3G networks offer data rates which are much higher. Recent versions, which are denoted as 3.5G and 3.75G, provide many Mbit/s in data rates, and mobile broadband has revolutionised the way online content is delivered to the mobile user.

4G - 4^th Generation Mobile Telecommunications

Replacing 2G and 3G, 4G wireless networks provide comprehensive IP based services including voice, video and data. With connection speeds of up to 100Mbit/s for high mobility communication (such as from trains and cars) and 1Gbit/s for low mobility communication (such as pedestrians and stationary users), 4G networks will revolutionise the future of mobile devices and how information is consumed by mobile devices.