MITS5003 Wireless Networks and Communication Assignment Solution

This assignment solution addresses various aspects of wireless networks and communication. Part I focuses on encoding techniques, error control, and data rate calculations, including a specific example involving a micro robot. It covers NRZ, bipolar encoding, ASK, FSK, and PSK modulation, as well as CRC calculations for error detection. Part II delves into multiplexing and multiple access techniques, including FDMA, TDMA, and CDMA, and compares 3G and 4G technologies and WiMAX. Part III explores Wi-Fi, covering BSS, ESS, throughput, and IEEE standards. The solution provides detailed explanations, diagrams, and calculations to illustrate key concepts in wireless communication systems.

Wireless
networks &
communication

Wireless networks &
communication
Contents
Part I: Encoding and error control 2
a) 2
b) 2
c) 3
d) 4
e) 6
Part II: Multiplexing and multiple access 7
a) 7
b) 8
c) 9
Part III: Wi-Fi 10
a) 10
b) 11
c) 12
d) 12
e) 13
References 14
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Part I: Encoding and error control
a)
Information exchange rate is that the rate that a correct amount of data is exchanged
over a given sum in time. So, we can state that: (Data Transfer/Time Taken).
Accordingly, on condition that estimating framework transmit four bits per second then
the coveted rate for machine to remote controller correspondence is 0.50 byte/sec.
b) The different techniques are as below: -
1. Encoding Techniques: -
NRZ: - To determine the reliability of voltage level, the NRZ give a property in the
midst of somewhat between time. 1 bit denotes unusual state of voltage and bit 0
denotes the lower level of voltage.
The two assortments are according to the accompanying:
• NRZ-Level
• NRZ-Inverted
2. Bi-polar encoding:
A Bipolar encoding is an encoding in which following properties accessible:
• Balance rate is double as compared with NRZ and transmission limit arguably
more unmistakable. (Modification is the position that shows the rate. This rate in return
show at which it is modified.).
• Since there is obvious change in the midst of each piece span of time, the
authority can be synchronized on that advance i.e. the timer is isolated to the banner.
• There would be advance toward the begin and likewise in the midst of the bit
between time the time works at twofold the data conversion scale.
c)
i) The status of string is 010111111 in this parallel case.
ii)The extend form of Ask, FSK, PSK are phase shift key, frequency shift Key, and
amplitude shift key.
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ASK: -
FSK:-
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PSK: -
fig: Diagrams shown representation of ASK, FSK and PSK for string 10110
d)
Ans. Divisor: 11001101, Data word: 11110000000
At that point CRC (cyclic repetition check) =
our CRC polynomial sequence is 11110000000 and CRC divisor is 11001100101 then
solution is:
CRC polynomial:
P(x) = x10+ x9+ x8+ x7
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The CRC checksum here:
0000000000 is the initial CRC value
Next hex digit [1]:
Shift in of [0] results in 0000000000
Shift in of [0] results in 0000000000
Shift in of [0] results in 0000000000
Shift in of [1] results in 1110000001
Next hex digit [1]:
Shift in of [0] results in 0010000011
Shift in of [0] results in 0100000110
Shift in of [0] results in 1000001100
Shift in of [1] results in 0000011000
Next hex digit [0]:
Shift in of [0] results in 0000110000
Shift in of [0] results in 0001100000
Shift in of [0] results in 0011000000
Shift in of [0] results in 0110000000
Next hex digit [0]:
Shift in of [0] results in 1100000000
Shift in of [0] results in 0110000001
Shift in of [0] results in 1100000010
Shift in of [0] results in 0110000101
Next hex digit [1]:
Shift in of [0] results in 1100001010
Shift in of [0] results in 0110010101
Shift in of [0] results in 1100101010
Shift in of [1] results in 1001010100
Next hex digit [1]:
Shift in of [0] results in 1100101001
Shift in of [0] results in 0111010011
Shift in of [0] results in 1110100110
Shift in of [1] results in 1101001100
Next hex digit [0]:
Shift in of [0] results in 0100011001
Shift in of [0] results in 1000110010
Shift in of [0] results in 1111100101
Shift in of [0] results in 0001001011
Next hex digit [1]:
Shift in of [0] results in 0010010110
Shift in of [0] results in 0100101100
Shift in of [0] results in 1001011000
Shift in of [1] results in 0010110000
0b0 (hexadecima
l)
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%
0010110000 (binary)
! 176 (decimal)
e)
Flow Control:
Flow control accelerates that extent of data which will be sent before obtaining
affirmation. it's a standout amongst the foremost imperative obligations of the
knowledge connect layer. Stream control advises the sender what quantity data to send.
Window sliding and Stop-&-pause are techniques used for stream controlling.
Controlling the Error:
The control of the error in the information connect layer depends on ARQ (programmed
rehash asks for), which is that the retransmission of data. Whenever a slip-up is known
in a very trade, indicated outlines are retransmitted. This procedure is termed ARQ
which is to ensure dependable correspondence, there requirements to exist stream
control and mistake control. Flow and Error control should to be ended at a couple of
layers. Designed for hub to-hub connections, stream & mistake control is done within
the data interface layer. For both the end points, stream and control of the error
completed within the vehicle layer.
Process of controlling flow and error
(I)Stop & Wait method: -
This procedure proceeds until the point that the sender communicates an End of
Transmission (EOT) outline. In Stop-and-Wait stream control, the beneficiary shows the
aforementioned availability to get information for each case. For each case which is
shared, there would be an affirmation, that would take a comparable measure of
engendering time to return to the sender.
(ii) Go-back-n ARQ: -
Collector window measure is 1. Now as the part of this strategy, on the off chance that
one casing is lost or harmed all edges sent, since the last edge renowned are
retransmitted.
(ii) Selective Repeat ARQ: new highlights: -
In this process only, damage packet is retransmit. So, that Sam can use one of them to
ensure the accuracy of robot control.
Part II: Multiplexing and multiple access
Multiplexing assumes a pivotal part in correspondence since it allows the blend of
different streams along totally unique multiplexing strategies zone unit utilized for
various applications.
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a)
Multiplexing could be a method through numerous signs of territory unit .In the
meantime it is transmitted more than one connections. Multiplexed framework
includes “n” scope of gadgets that offer the capacity of 1 interface which is anyway a
connection (way) to have numerous channels. Various gadgets bolstered their
transmission streams to an electronic gadget (MUX) that consolidations them into one
stream. At the beneficiary, the main stream is coordinated to the Demultiplexer
(DEMUX), that is yet again converted into its part transmission and sent to their
gathered collectors.
The distinction between TDM, FDM and CDMA on these diverse parameters are as per
the following: Idea, Terminals, Signal Separation, Transmission Method, Cell Capacity,
Advantages, Disadvantages.
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Fig: Diagram Of FDMA, TDMA and CDMA
b) The WiMAX is displayed through the IEEE that is standard chosen 802.16d-2004
(utilized for mounted remote sales) and 802.16e-2005 to supply an overall capacity for
microwave get to. At introduction, media transmission businesses zone unit amazingly
included with the remote transmission of information which may utilize various
transmission modes, from point-to-multipoint joins. It contains full versatile net access.
various applications have just been connected to this point abuse WiMAX.
Technologies 3G 4G
Cellular
Services
Higher Capacity, Broadband
Data up to 2Mbps
Higher Capacity, completely IP
Based, Multimedia Data
Bandwidth 2 Mbps 10 Mbps - 20 Mbps
Core Network Packet Network All-IP Networks
Design Began 1990 2000
Developed 2002 2010
Multiplexing CDMA FDMA, TDMA, CDMA
Versions WCDMA, CDMA-2000 OFDM, UWB
c)
i)In OFDM framework, the transporters territory unit bending. To amounted bending
signals territory unit known as symmetrical once their basic item is sufficient to zero
more than one period. Each symmetrical subcarrier has Associate in Nursing (whole
number/entire range/number) number of cycles in an exceptionally single measure of
OFDM framework. To dodge between channel obstruction these zero bearer’s territory
unit utilized as a protect band amid this framework.
ii) OFDM could be a similarly new frightfully efficient computerized regulation subject
that utilizes different bearers that zone unit proportionally symmetrical to 1 another
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over a given interim. each transporter, comprising of a join of undulation and a cos
wave, is alluded as a 'sub-bearer'.
Significance of the thoughts of Orthogonality in Digital Communications-
a.) Inside the style and selection of information bearing heartbeats, symmetry could
likewise be acclimated advantage for deduction efficient image by image gathering
topic.
b.) Execution examination of numerous regulation gathering plans are regularly
apportioned if the data bearing sign waveforms region unit recognized to be
symmetrical to each unique.
c.) The thoughts of symmetry are frequently acclimated advantage inside the style and
decision of single and numerous transporters for tweak, transmission and gathering.
iii)The Orthogonal Frequency Division Multiplexing (OFDM) is produced to help high
rate and may deal with multi bearer signals. Its claim to fame is that, it will limit the
bury picture Interference (ISI) rather more contrasted with various multiplexing plans.
it's a ton of conceivable enhanced Frequency Division Multiplexing (FDM) as FDM
utilizes protect band to constrict obstruction between totally extraordinary frequencies
that squanders innumerable data measure anyway OFDM doesn't contain between
bearer monitor band which may deal with the impedance a considerable measure of
speedily than FDM. OFDM also handles multipath come about by changing serial data to
numerous parallel data abuse brisk Fourier improve (FFT) and Inverse fast Fourier
modify (IFFT).
Information transmission is sufficiently high contrasted with FDM as OFDM takes after
multicarrier regulation. For this, OFDM parts high data bits into low data bits and sends
each sub-stream in numerous parallel sub-channels, called OFDM subcarriers. These
subcarriers territory unit are symmetrically unique. In this way each subcarrier data
measure is far lesser than the entire data measure. ISI is diminished in OFDM strategy
on the grounds that the picture time Ts of each sub-channel is over the channel delay.
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Fig: Block diagram of OFDM
To maintain a strategic distance from (ISI) the Cyclic Prefix (CP) is embedded in OFDM
framework before each transmitted picture. In unguided transmission the sending signs
can be delude by the outcome because of commotion and different issues. The
Directorate for Inter-Services Intelligence (ISI) is totally dispensed with by the
arranging once the CP length is bigger than multipath delay.
Part III: Wi-Fi
a) Backbone organize: - A spine might be a piece of system that interconnects shifted
things of system, giving a way to the trading of learning between entirely unexpected
LANs or subnetworks. A spine will tie along different systems inside a similar working,
in various structures in an exceptionally field setting, or over wide territories.
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b) A BSS comprises of a group of PCs and one AP, that connects to a wired PC organize.
relate ESS comprises of very one AP. relate ESS gives portable clients a chance to roll
wherever at interims the domain lined by different APs.
Presently some fundamental contrasts amongst BSS and ESS are as per the following: -
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