Investigation of the Performance of Wired and Wireless Communication Systems

INVESTIGATION OF THE PERFORMANCE OF WIRED AND WIRELESS COMMUNICATION SYSTEMS

Abstract

Communication has become important to our lives and a big industry for business throughout the world. Normal life would be very hard without communication. There are different kinds and means of communication i.e. wired and wireless communication. In this report the discussed and analyzed detail of both wired and wireless communication is given with thorough study with the help of results achieved from the practical experiment. Comparison is done between both of kinds of communication and results.  

Introduction

Communication is actually a method of sending data in the form of signals as wave or electrons which is called transmission then sent through different mediums air or wire and then receiving the data through receiver. Before advancement people used different kinds of processes to communicate with each other and now the world has become a place where it is very hard to live without good means of communication.

Communication system is basically the combination of different processes together as shown in  the showing block diagram of communication system. Firstly the information source provides a message signal to the transmitter where it is modulated and its frequency is boosted and the transmitted into the channel. The channel could be air or wire or optical fiber then it received at the receiver and demodulated there after reception to get the message signal back. So according to the channel or medium through which the transmission is done the communication could be divided into three types which are the transmission through air or wireless communication which needs antennas at transmitting and receiving ends of the system and the other two wire and optical fiber are wired connections which needs wire as medium of transmission. But our focus here is just the study of wired and wireless communication which is done under certain conditions and circumstances to know about the advantages and disadvantages of  both ways of communication for better understanding of the scenario.  

The main objective of the report over conducted experiment is to study and analyze the communication through wire and wireless medium. And discuss the results to conclude the about both mediums and compare their behavior according to different conditions of nature and technicality. The apparatus used in experiment conducted was Network analyzer R&S®ZVL6 which is analyzing the transmission coefficient (S21) of the transmitted signal, a wire (coaxial cable) and two monopole antennas as medium for the transmission, 10dB attenuator, one band pass filter, measuring tape for measuring separation and a metal sheet.

Study of wired Communication link with results, analysis and discussion:

As discussed that communication is the process of transmission and reception of the data through a medium so if the medium of transmission and reception is wire then the communication is called wired communication. Wired communication is very important part of the communication world such as broadband services like TV broadcast, Telephone and internet which completely relies on wired communication and can’t be ignored. In this very experiment the first part is to set up a wired link with Network Analyzer R&S®ZVL6 for examining the communication through coaxial cable as given in the figure 1.0.

        Figure 1.0

As coaxial cable is used in the event so, in coaxial cable, the going wire is in the center which is conductor, which is a form of copper wire, any solid or stranded form, and small in diameter, which is wrapped by a very heavy insulation and the dielectric. The returning wire is also made of copper but unlike the going wire it is in the form of a copper tube completely surrounding the going wire and dielectric, and concentric with it; that is why it is called coaxial cable. Thus, your transmission can’t be affected by any external interference because it is totally shielded from external effects by the tubular returning conductor and it is carried by currents through the cable.

Coaxial cable has an extremely broad bandwidth; it will transmit signals from zero frequency up to millions of hertz of frequencies which means hundreds of messages can be frequency multiplexed and transmitted simultaneously over a single coaxial cable, or a television program occupying about 3,500,000 Hz can be transmitted simultaneously with hundreds of phone conversations. Coaxial cable has a low attenuation and it does not need as many amplifiers as when using a simple conventional wire.

Firstly we connected one end of the cable to the output (Port 1) channel of the network analyzer as given in figure 1.1 which was actually generating or transmitting a wave of certain band of frequency starting from 9 KHz and ending at 6 GHz. And for calculating the transmission coefficient denoted as (S21) for standard coaxial cable in network analyzer connected the other end of it to the RF input (Port 2) of the network analyzer.

The result as S21 achieved after connecting the cable to the network analyzer are as following in the figure 1.2[pic 1]

Figure 1.2

Attenuator is an electronically designed device used to reduce the power gain of a signal without distorting or damaging the signal. The 10dB gain attenuator used in experiment is given in the figure 1.3 (a). Then we connected an attenuator to one end of the cable to see the transmission in the presence of attenuation we achieved the results as follows given in the figure 1.3 (b). We can clearly see the reduction of power gain in the signal after connecting the attenuator to the cable. So, if we compare the S21 of the connection without attenuator to it there is a clear reduction of approximately 10dB in the gain of the signal without large distortion in the signal after connecting attenuator.  

Figure 1.3 (a)

[pic 2]

Figure 1.3 (b)

Filters are basically used to suppress the unwanted signals with different frequencies and allow the required signal frequency to improve the quality of the signal and reduce noise factor of the signal. Filters are of different types but the filter used in this experiment is band pass filter which allows those frequencies which lays in a certain range of frequency (which is 710-850 MHz) it means that it allows the frequencies between this very range of frequency and stops all other frequencies. Now we removed the attenuator and connected a band pass filter is given below