ELEC S425F Computer and Network Security
Assignment 3
Releasing Date: 10:00 AM, 23-April-2022 (Sat)
Closing Date: 09:59 AM, 30-April-2022 (Sat)
No late submission is allowed!

Your Name:
Student ID:

Question:
Consider a downlink NOMA system with three users (M=3). Therein, 1 is a passive eavesdropper
who tries to intercept the information of the other users. The corresponding channel state information
is given in the following figure. Besides, the noise power is assumed to be N. The system bandwidth
is 1. In addition, the targeted data rate per user is set to be , where =1,2,3. Moreover, let be the
transmit power of user , where =1,2,3. Denote by the transmit power of the jammer. (Note that
| ℎ,1 |>| ℎ,2 |>| ℎ,3 |)
(a) Please derive the expression of secrecy rate of the system [10 marks]
(b) Please discuss what conditions should be satisfied such that the secure transmission is ensured
[20 marks]
(c) Without considering the effect of eavesdropper, calculate the required minimum power to
satisfy the data rate requirement pre user [20 marks]