First generation of mobile networks

The mobile wireless technology creation, development, revolution and evolution started in early 1970s. In past four decades mobile wireless technology has come a long way in terms of data transfer speed, spectrum efficiency and bandwidth utilization techniques. Mobile network technologies are classified according to their generations which are based on types of services and data rates they provide to the end-user.

Zero G refers to the pre-cellular mobile telephony technology era. In the beginning (In 1970s) the mobile telephone systems were huge and were usually mounted on vehicles. They were called radio telephone systems and are considered to be the predecessors of modern cellular mobile phones. That is why they are sgenerally referred as belonging to 0G. Communication technologies used in 0G were PTT( Push To Talk) , MTS (Mobile Telephone Systems), IMTS(Improved Mobile Telephone Systems) and AMTS(Advance Mobile Telephone Systems) etc.

Understanding First Generation (1G) Mobile Networks

First generation refers to the handheld mobile phones using analog communication techniques to transmit voice over radio waves. These phones were large and heavy with big antennas and were also referred as “brick phones” and “bag phones”.

1980 was the year when mobile cellular technology took first breath and since then it has experience rapid and enormous growth. In 1979 first cellular system in the world became operational by Nippon Telephone and Telegraph (NTT) in Tokyo, Japan. It uses analog transmission of speech services. Two years later Europe also joined the cellular club and thus the two most popular analog systems i.e. Nordic Mobile Telephone (NMT) and Total Access Communication Systems (TACS) were born. A few other analog systems were also developed by different European countries during that time. All these systems offered handover and roaming services but mobile networks were unable to interoperate among countries. This was one BIG disadvantage of 1G.

In USA Advance Mobile Phone Systems (AMPS) was launched in the year 1982. The system was allocated 40 MHZ Bandwidth with the frequency range of 800-900MHz. In 1988 an additional 10MHz bandwidth was added to the already available spectrum. AMPS offered 832 channels with the data rate of almost 10Kbps. Initially Omnidirectional Antennas were used but later on they switched to directional antennas because of its better cell reuse factor.

1G systems mostly used Frequency Modulation (FM) for radio transmission and the traffic on multiple channels was combined through Frequency Division Multiple Access (FDMA) System.

Disadvantages of 1G.

1. Analog Signals does not allow advance encryption methods hence there is no security of data 
2. Signal sniffing and signal jamming are very easy in analog system.
3. The user identification number could be stolen easily and which could be used to make any call and the user whose identification number was stolen had to pay the call charges.
4. Analog signals can easily be affected by noise and interference and the call quality decreases.
5. Analog systems were expensive and the call charges were very high.