Vertical Handoff in Wireless Cellular Networks
1. INTRODUCTION
Communication is always necessary in building relations to mankind, when two persons meet they need some medium to interchange their views but due to distance barriers some tools are required to communicate each other. At the end of 19th century, reckoned \scientist Graham Bell laid the first stone in the field of communication using different tools regardless of distance. He invented first wired base telephony equipment. It was the solution for the voice communication for the people how far apart they are. After this radio based communication systems Era started. It was an extension of wired based networks. In the beginning it was developed for some special purposes like military and police usage. With the passage of time these systems emerged to allow common peoples to communicate with each other, rather then using wired based network. After this the age of faster communication and capabilities of voice get started and evolved into new telecommunication system.
1.1 Evolution of Cellular Communication:
During the 1980s mobile cellular network’s age started, because the wireless communication has under gone different changes during the past 10 years, So its experienced enormous growth.
The Figure 1.1 shows the evolution of the cellular networks. In this figure we have categorized the Cellular networks into five different parts. The first four are existing parts and the last one is the future part.
Figure 1.1: Evolution of Cellular Network 1.2.1 First Generation (1G)
First Generation mobiles networks utilize analogue transmissions. In 1979 Nippun Telephone and Telegraph (NTT) in Japan introduces the first operational cellular networks. In North America AT&T introduces the First Generation mobile systems for the customer in 1980s. This system was named as Advanced Mobile Phone Service (AMPS). In First Generation the basic structure of Cellular communication is characterized and many problems were resolved regarding
Communication is always necessary in building relations to mankind, when two persons meet they need some medium to interchange their views but due to distance barriers some tools are required to communicate each other. At the end of 19th century, reckoned \scientist Graham Bell laid the first stone in the field of communication using different tools regardless of distance. He invented first wired base telephony equipment. It was the solution for the voice communication for the people how far apart they are. After this radio based communication systems Era started. It was an extension of wired based networks. In the beginning it was developed for some special purposes like military and police usage. With the passage of time these systems emerged to allow common peoples to communicate with each other, rather then using wired based network. After this the age of faster communication and capabilities of voice get started and evolved into new telecommunication system.
1.1 Evolution of Cellular Communication:
During the 1980s mobile cellular network’s age started, because the wireless communication has under gone different changes during the past 10 years, So its experienced enormous growth.
The Figure 1.1 shows the evolution of the cellular networks. In this figure we have categorized the Cellular networks into five different parts. The first four are existing parts and the last one is the future part.
Figure 1.1: Evolution of Cellular Network 1.2.1 First Generation (1G)
First Generation mobiles networks utilize analogue transmissions. In 1979 Nippun Telephone and Telegraph (NTT) in Japan introduces the first operational cellular networks. In North America AT&T introduces the First Generation mobile systems for the customer in 1980s. This system was named as Advanced Mobile Phone Service (AMPS). In First Generation the basic structure of Cellular communication is characterized and many problems were resolved regarding
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