{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture7 - ECE 340 Lecture 7 Variance conditional pmf Jean...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 340 Lecture 7: Variance & conditional pmf Jean Liu Email: [email protected]
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Example to review Problem 3.18 A computer reserves a path in a network. To extend the reservation the computer must successfully refresh message before the expiry time. The messages are lost with probability ½. Suppose that it take 10 sec. to send a refresh message and receive acknowledgement. When should the computer start sending a refresh messages in order to have a 99% chance of successfully extending the reservation time.
Image of page 2
10 min. 0 ? Refresh request
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Let X be the times that a refresh request needs to be sent till successfully received. • S X is {1,2,3,…} Let Y be the seconds that a refresh request needs to be sent till successfully received. • S Y is {10,20,30,…} Success rate of a message is 1/2 What is the set B, which begins with 1 and increases accordingly, has 99% chance of successfully extending reservation?
Image of page 4
pmf of X? 1 1 1 1 ( ) ( ) ( ) ( ) ( ) 2 2 2 k k X k p x p x K = = = = 1 1 [ ] ( ) ( ) 2 N k k k B k P B p x = = = Set B probability ?
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern