Revision Week, Fall 2008 Lecturer Madeeha Owais

Syllabus Satellite Communication – Link Budget or Link Design Calculations Part (Chapter 4 from Timothy Pratt Book) – Satellite Multiple Access (Reading reference pages from Timothy Pratt book specified in lecture slides) All this portion has been covered in Class Lectures in Lecture 5 to Lecture 10 (Downloadable from Website)

Cellular Communication – The Cellular Concept-System Design Fundamentals Chapter 3 from Rappaport Book Class Lectures: Cellular Concept (Lecture 1 to Lecture 4) Lectures are downloadable from website Video Lectures: Specially Lecture 6

Cellular Communication – GSM Lesson 1 to 6 of the CBT Do go through Lesson 7 of CBT for better clarity/flow understanding of things learnt in Lesson 1 to 6 GSM Authentication Tutorial(Downloadable from website, Studied in Class) Page of Rappaport Book, especially for GSM Channel Types and Frame Structure

Cellular Communication – Mobile Radio Propagation: Large Scale Path Loss Chapter 4 from Rappaport Book Class Lectures: MRP (Lecture 1 to Lecture 3) Lectures are downloadable from website Closely follow the instructions I have written down in lecture slides to read what from where

Video Lectures Video lectures can be as additional resource for cellular communication part. Link to access video lectures on YouTube is given in the Announcements part of the Website You can also take them from me

Paper would have two parts – Objective (Max 30 mins) – Subjective (Max 2 hr 30 mins) Paper would consist of: – Numericals – Scenario based problems – Reasoning Explanations as Theory Part – Answer briefly type questions as given in Midterm Exam

Please see your sessional result (out of 40%)today before leaving the class!!! Sessional Result

REVISION Recursive Model Query of last lecture 2 Numerical Examples from Diffraction Topic in the Chapter 4 of Rappaport Book Link Margin Calculation in Satellite Communication Link Budget How Frequency Hopping helps prevent interference?

10 h obs h h is positive, v is positive h obs h is zero, v is zero h obs h h is negative, v is negative EXAMPLE 4.7 of BOOK, page !!! Compute the diffraction loss for the three cases shown in figure shown

Example 4.7 (contd) Assume λ=1/3m,d 1 =1km, d 2 =1km a)h=25 m b)h=0m c)h=-25m Compare your answers using values from Diffraction Loss Graph as well as numerical solution from gain equations For each of these cases,identify the fresnel zone within which the tip of the obstruction lies

Diffraction and Fresnel Zones 12

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Diffraction and Fresnel Zones Fresnel Zones: Assume that the obstruction is placed at a distance of d 1 from transmitter and d 2 from receiver. x b r 1 a d 1 d 2 if b = a + λ/2 then point x is said to lie on the 1 st fresnel zone. The loci of all the points which satisfy the above condition will form a circle. 14

Diffraction and Fresnel Zones Fresnel Zones: Assume that the obstruction is placed at a distance of d 1 from transmitter and d 2 from receiver. b r 1 a d 1 d 2 Similarly all the points for which path length for the secondary waves is greater than the LOS path by λ lie on the 2 nd fresnel zone.(i.e. b = a + λ ) Thus the path length of the n-th fresnel zone circles is n λ/2 longer than the path length of the LOS path. 15

Diffraction and Fresnel Zones Fresnel Zones: The radius of the n-th fresnel zone circle is denoted by r n and can be expressed in terms of n, λ, d 1, and d 2 by: 16

Example 4.8 As done on board!!!