Wireless Networking: Spread Spectrum Transmission, Radio System Components, and Mixer Types

Running head: WIRELESS NETWORKING
WIRELESS NETWORKING
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Question 1
Signals that are wireless conventional generally has some frequency, that are specified by
megahertz and by gigahertz. These frequencies do not change with respect to time. The digits of
radio frequency remain same all the time (Chen & Hashemi, 2014). The frequency is always kept
same at all the time in a signal, which is conventional wireless. As a result of this, the bandwidth
of the signal are kept in a certain limit and therefore, the signals can be located easily by some
other person who want to intrude the signal and retrieve all the data on that network.
Need for spread spectrum transmission
With the conventional wireless communication, there are certain problems that arise with
the frequency of bandwidths. The signal that has a constant frequency is automatically subjected
to some catastrophic interference. This catastrophic interference occurs when another signal of
almost similar frequency is transmitted very near to the transmitted signal (Cai, 2015). The
catastrophic interference that occurs can be of two types- deliberate catastrophic or an accidental
catastrophic interference. Second most problem that arise with constant frequency is those
signals can be easily intercepted and so, constant signals are not at all appropriate for
applications that are to keep confidential data in between the transmitting party (source) or the
receiving party (destination).
So, to overcome these problem that arise from conventional constant frequencies, spread
spectrum transmission is used. The signals that are transmitted over the network are varied so
that there is no change of catastrophic interference or intercepted signals. The transmission is

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basically varied over a large segment of spectrum that has electromagnetic radiation. There are
specific mathematical functions for varying the signals of spectrum that are transmitted.
Types of spread spectrum transmission
There are commonly three types of spread spectrum transmission- Direct-Sequence
Spread Spectrum, Chirp-Spread Spectrum, and Frequency-Hopping Spread Spectrum.
Direct-Sequence Spread Spectrum- The most common type of spread spectrum that is
used widely is the Direct-Sequence Spread Spectrum. By multiplying radio frequency carrier and
pseudo noise, the process of Direct-Sequence is acheived. There is binary code known as the PN-
Code that is produced at very high frequency compared to the data that is sent for transmission.
Since, there is a high frequency, the signal is followed by large bandwidth. The data that is send
through Direct-Sequence Spread Spectrum transmission is multiplied with some noise that is
known as pseudorandom code (Edwards & Steer, 2016). The PN-Code is basically modulated on
information signal. The pseudorandom code that is generated in noise consists of number ranging
from 1 and -1. Higher frequency of signals can be achieved on multiplying the PN-Code with the
original data leading to spreading of energy.
Chirp-Spread Spectrum- The Chirp-Spread Spectrum is usually a technique that includes
using the linear frequency chirp pulse that are modulated for encoding the information. A chirp
can be technically defined as sinusoidal signal in which the frequency of the signal decreases or
increases over a span of time. The complete bandwidth that is allocated to the Chirp-Spread
Spectrum is used for the transmission of signal and makes the signal a stringer one against any
kind of interference or signals (Koda et al., 2016). The signal of data that is transmitted, spreads
over wide range of frequency band through Chirp-Spread data spectrum transmission. The

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transmission of Chirp-Spread Spectrum is resistant to the multi-path fading. Pseudo-random
codes are not used in this type of transmission. This spectrum transmission depends on the chirp
nature pulse that is considered to be a linear one. The Doppler Effect is also protected by this
transmission method. CSS techniques are used recently for the purpose of wireless
communication so that there does not exist any type of jamming or any interference in the signal.
Frequency-Hopping Spread Spectrum- In Frequency-Hopping Spread Spectrum
transmission, a transmitter is generally hopped in between the frequencies that are available. This
is done according to some predefined algorithm or some programs that is created randomly or
was pre-planned. The Transmitter or the receiver are synchronized together with same frequency.
A small part of the data is basically transmitted over a narrowband at some frequency. Therefore,
hopping the frequency is capable over the transmitter over the given bandwidth for multiple
times in a second (Tang & Pan, 2016). This hopping transmits a particular frequency of signal
over a certain time period and then hops to some other frequency and transmits again.
Question 2
Different components used for radio system
There are basically two types of components that are available- a receiver and a
transmitter.
Radio Transmitters- Several elements are present in a radio transmitter that works
together for generating the radio waves containing useful data or information including digital
data, video, or audio (Diemer, Wheeler & Nocera, 2014). The elements of radio transmitter are: