Begin by filling in your student id number, your name, the name and code of this course and the date of the exam. There are five questions in this exam. You are allowed to answer only four of them. Answer shortly and stick to the point. Use good language and clear handwriting. Read all the questions carefully before you begin answering them.
Write answers to question 1-3 and 4-5 on different answer sheets. Also remember, that you only need to answer four questions out of five.
Explain the following terms / concepts.
a) modulation
b) multiplexing
c) cell switching
d) CE marking
e) radio horizon
f) gateway
a) Explain what is line coding. How is it connected to synchronization?
b) Draw a picture of bit sequence 0100111010 coded with two different line codings of your choice. Explain the principles of your line codings verbally.
a) Explain what is a protocol reference model. What are the benefits of using a standard reference model in telecommunications technology?
b) Explain the terms connection oriented and connectionless protocols. What are the differences between the two (in principle and in practice).
c) How are different tasks divided between TCP and IP protocols during data transmission?
Change the answer sheet.
a) Optical fibres are used in telecommunications especially on long distances. Why? Justify your answer, and compare optical fibres also with other transmission media.
b) Even in optical fibres, the signal does not propagate ideally. What kind of phenomena can disturb the propagation of a signal in optical fibres?
c) Explain what is dispersion. Draw also pictures to clarify your meaning. How does this phenomenon affect transmission in different types of optical fibres?
d) Explain what is WDM-technology.
What were the first elementary telephone networks like? Compare their structure to a modern cellular network. What new challenges does the introduction of mobility bring to telephone networks? Draw pictures to clarify your meaning and give names to different network elements in your pictures.
Remember to answer only four questions!
Kirsi Willa, Johanna Koivisto and Mari Sipilä.