Special Assignment : Mid Term
Exam
Spring 2021
CS718: Wireless Networks
Due date: 22-June-2021
Total Marks: 50
Page No 1 of 5
Obtained Marks
Objectives
All questions in this assignment cover the topics from lecture 1 to 22. For all questions, your
answer must be concise, to the point, and compact not more than 8 to 10 lines.
Instructions to solve Assignment
1. This assignment contains four questions, students are required to solve all of
them.
2. Students should prepare the solution and upload it on LMS as soon as possible
without waiting for the due date to avoid issues resulting from internet
connectivity or power failures etc.
3. Assignment should be solved using Time New Roman format and Size of 12.
It should be clear that your assignment will not get any credit if:
•
The assignment is submitted after the due date.
•
The assignment is not in the required format (Only MS Word Format is allowed)
•
The submitted assignment does not open or file is corrupt.
•
The assignment is copied (partial or full) from any source (websites, forums, students,
etc.)
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The assignment sent by email will not be accepted.
Page No 2 of 5
QUESTION NO 1. (14 Marks)
a) Consider the following analogue signals
𝒔𝟏 (𝒕) = 𝑨 𝑪𝒐𝒔 (𝟒𝝅𝒇𝒕 + 𝝓) with A = 10 and 𝝓 =
𝒔𝟐 (𝒕) = 𝑨 𝑪𝒐𝒔 (𝟖𝝅𝒇𝒕 + 𝝓) with A = 15 and 𝝓 =
𝝅
𝟒
𝝅
𝟔
and frequency = 4Hz.
and frequency = 8Hz.
Draw and label the waveform diagrams in the time period from −𝟏 𝒕𝒐 + 𝟏 seconds and find
the signal amplitude at -0.5 , -0.55 and 0.6 seconds for each of the signal.
b) How 3rd generation cellular systems are different from GSM in terms of network architecture.
Use suitable diagrams to explain.
Question No 2 (6 Marks)
Discuss the differences and similarities between Wireless Fidelity and Cellular Networks. How
these networks can be converged along with benefits for users and network service providers.
Question No 3 (10 Marks)
Scenario:
A standard cell with N=4 system has a radius of 0.862 miles. Sixty channels are used within the
whole system. The traffic intensity per user is 29 mErlang, and λ = 1 call/hour. The system uses
Erlang C distribution with 5 percent delay probability.
Page No 3 of 5
Figure 1 - Erlang C Distribution
Considering above scenario , answer the following questions.
a) How many users in square kilometer can be supported by the system?
b) Calculate the probability that a delayed call will have to wait for more than 10 seconds?
c) Determine the probability that a call will be delayed for more than 10 seconds?
Question No 4 (10 Marks)
A city with 4,000,000 users is served by different mobile network operators MNO1, MNO2 and
MNO3. MNO1 has 400 cells each having a capacity of 19 channels. The MNO2 has 150 cells and
each cell has capacity of 57 channels. The MNO3 has 250 cells with 100 channels capacity per cell.
Using the Erlang B Distribution , Answer the following questions.
Page No 4 of 5
Figure 2 - Erlang B Distribution
1. What are the maximum number of supported users by each MNO with 2% blocking given
each user makes 2 calls per hour with average duration of 180 seconds?
2. If all operator ‘systems are working at maximum load, what is the market share of each
operator.
Question No 5 (10 Marks)
Consider the binary data 10101011. Determine the hamming code to transmit the data over
network. You need to show all steps including the calculation of the parity bits their values with
odd parity.
Note: Assignment Solutions only in MS WORD format shall be accepted,
Best of Luck
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