Question 2

(a) Explain the meaning of the following termsin the context of cellular telephony networks:

(i) Frequency reuse

(ii) Trunking

(iii) Micro and macro cells

(iv) Umbrella cells Describe the trade-off thatmust be made when selecting the number of cells which should beclustered together to form a location area in a cellular network.[6 marks]

(b) A number of techniques are used on both thebase station and mobile station (i) to managepower consumption, and (ii) to minimise theeffects of network interference. For each of the following terms,describe how the feature works and comment on whether, and how, itis used to address (i) and\or (ii).

(i) Time Division Duplexing

(ii) Adaptive Power Control

(iii) Discontinuous Transmission [4.5marks]

(c) Subscriber A is a subscriber of an Irishmobile network who is roaming on a French mobile network.Subscriber B is a subscriber of UK mobile network who is currentlyan inbound roamer on subscriber A’s home network. Subscriber Ainitiates a voice call to subscriber B.

(i) Describe, with the aid of a diagram, thesteps involved in the routing of this call to the point wheresubscriber B’s handset is paged.

(ii) Using this example, clearly explain thedifference between late and early call forwarding.

(iii) Explain the meaning of the term calltromboning in the context of one of these call forwarding scenariosand outline how this is typically resolved when it occurs.[9.5 marks]