Department of Engineering 2022
7CCEMMPC
Mobile and Personal Communication Systems

Coursework 1

Introduction
This is the first (of two) pieces of coursework and is worth 15% of the module mark. It tests your ability
to solve problems based on the material in the first half of the module. You should solve each of these
questions showing and explaining your method clearly.
You should submit a single PDF containing your answers, working, derivation and clearly explaining
your assumptions and method. The maximum document size should be 5-pages. This may be a scanned
hand-written document.
The deadline for submissions is 23rd February (within the submission window). For students with
unforeseen circumstances, you can submit a mitigating circumstances form via student records. Note
that I cannot grant extensions or modifications to assessments.
For support with the assessment, you may ask clarification questions via the forum and my office hours
are Mondays from 10AM to 12PM.
Coursework 1 Questions
Question 1)
Derive a simple expression for the capacity (number of users per cell) of a CDMA cellular
mobile system, assuming it employs a perfect power control scheme and the effect of thermal
noise on the capacity of the system is negligible.
(40 marks)

Question 2)
A Direct Sequence-Code Division Multiple Access (DS-CDMA) cellular mobile system uses
Quadrature Phase Shift Keying (QPSK) modulation having raised-cosine shaped filtering with
roll-off factor of 0.22. Its base stations are equipped with 3-sector antennas. The user data rate
is 32 Kb/s, spreading factor is 128, voice activity factor is 1, and inter-cell-to-intra-cell
interference power ratio is 1/2. If a desired bit error rate per user of 10-3 is required, calculate
how many users one cell can serve. Assume that the effect of thermal noise on the number of
users is negligible.
(60 marks)