MITS5003 Wireless Networks & Communication Assignment Solution 2019

This assignment solution covers key concepts in wireless networks and communication. It begins by exploring various modulation techniques including Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), and Phase Shift Keying (PSK), calculating the time required for signal transfer with different modulation levels. The solution then delves into the Multilevel Frequency Shift Keying (MFSK) and provides the formula for calculating frequency values. The assignment further investigates the Cyclic Redundancy Check (CRC) technique for error detection in data transmission, including its working algorithm. Additionally, the solution addresses a cellular communication problem, calculating mean occupied time, mean rate, and traffic intensity for multiple users. Finally, it discusses different cell shapes (square, circle, and hexagonal) used in cellular communication, highlighting the advantages of the hexagonal shape. References are provided for further reading on these topics.

Wireless network and communication

WIRELESS NETWORKS 1
Answer 1
a. Two-level Amplitude Shift Keying
b. Two-level frequency-shift keying
c. Two-level Phase Shift Keying
d. Differential Phase shift keying
e. Four level Amplitude Shift Keying

WIRELESS NETWORKS 2
f. Four level Phase Shift Keying
g. Eight level Amplitude Shift Keying
Answer 2
The time needed for transferring one signal= 1 μs (microseconds)
Total time= [(signals transmitted by the consumer)*(1 μs)]
Two-level amplitude shift keying
Total time= 12 microseconds (μs)
Two-level Frequency Shift Keying
Total time= 12 microseconds
Two-level Phase Shift Keying
Total time= 12 microseconds

WIRELESS NETWORKS 3
Differential Phase shift keying
Total time= 12 microseconds
Four level Amplitude Shift Keying
Total time= 6 microseconds
Four level Phase Shift Keying
Total time= 6 microseconds
Eight level Amplitude Shift Keying
Total time= 4 microseconds
Answer 3
According to the MFSK, the value of frequency may be gathered using the below formula:
Here, Fc= 50 KHz, M= 16, L= 4, Fd= 50 KHz and “i” can be varied between 1 and 16.
F1= 1000+ (2*1-4-16)*50
Or, F1= 100 KHz
Similarly, other values may be obtained and highlighted below:

WIRELESS NETWORKS 4
Answer 4
Amplitude modulation waveform
Frequency modulation waveform
Answer 5

WIRELESS NETWORKS 5
Answer 6
Answer 7
Cyclic redundancy check is defined as a technique that has the capability to detect error from the
transmitted signals from the source to destination. It is examined that the involvement of the
CRC technique is helpful in the data communication due to their potential to provide better
signals to the receiver and reduce the errors from the signals [1]. The major function of the CRC
process is that it performs a division process among the number of bits and the transmitted
signal.
Figure: Working algorithm of CRC technique [1]

WIRELESS NETWORKS 6
According to the CRC technique, if the value of reminder is completely zero then the transmitted
signal has no error or risk. If the remainder is non-zero value then the receiver can suffer from
the noise and distribution while receiving the transmitted signal. Therefore, using the working
process of the CRC method the consumers can manage risks and find errors from the signals
effectively [2].
Answer 8
As per this problem, there are five consumers included in the cellular communication such as
U1, U2, U3, U4, and U5. The total time duration for these consumers is 180 minutes and time of
each user is represented as T1, T2, T3, T4, and T5.
Total occupied time= 150 minutes (by adding the given times for each user)
Total occupied cells= 50 cells per consumer
Mean occupied time= sum of all occupied time by each cell/ 5
 For U1= 0.5 min/cell
 For U2= 1 min/cell
 For U3= 20 min/cell
 For U4= 3.5 min/cell

WIRELESS NETWORKS 7
 For U5= 4 min/cell
Mean occupied time= (0.5+1+20+3.5+4)/5= 5.8 min/cell
Mean rate= 1/mean occupied time
So, mean rate= 0.717 cell/min
Traffic intensity= sum of all traffic intensities (for each cell)
For U1=
For U2=
For U3=
For U4=
For U5=
So, traffic intensity= 51.9 Erlangs
Answer 9
There are three types of shapes involved in the cellular communication for connecting number of
cells including square, circle and hexagonal shapes [3]. In which square and circle are less likely
towards the cellular communication due to their numerous drawbacks including, less
effectiveness, larger complexity, enhancement of risks and errors in the systems and so on.
However, hexagonal shape has the potential to shelter the whole area without overlapping and
reduce all these issues in a reliable way due to which it appropriate for cellular communication
[4].

WIRELESS NETWORKS 8
References
[1].B., Li, H. Shen and, D., Tse, “An adaptive successive cancellation list decoder for polar
codes with cyclic redundancy check,” IEEE Communications Letters, vol. 16, no. 12,
pp.2044-2047, 2012.
[2].G. Shanthi and, L., Padmasree, “CHIPSCOPE Implementation of CRC circuit
architecture,” IOSR Journal of VLSI and Signal Processing (IOSR-JVSP), vol. 2, no. 1,
pp.07-14, 2013.
[3].P. Mittendorfer and, G., Cheng, “Uniform cellular design of artificial robotic skin,”
In ROBOTIK 2012; 7th German Conference on Robotics, vol. 12, no. 6, pp. 1-5, 2012.
[4].D., Wu, Z., Ghassemlooy, S. Rajbhandari and, H., Le Minh, “Channel characteristics
analysis and experimental demonstration of a diffuse cellular indoor visible light
communication system,” The Mediterranean Journal of Electronics and
Communications, vol. 8, no. 5, pp.1-7, 2012.