Homework #2 - CSIS 625 - Fall 2003 - Section 1
Due Week 6 (October 13, 2003) by classtime

Email this document with your answers filled in to droelke@stthomas.edu
The email should contain your answers as plain text in the body of the document.
It should not be sent as an attachment to your email.
If you quote something for an answer - be sure to give the page number, 
which week of class notes, or the full URL, for each citation.

Name:

Define the following:
1) Synchronous TDM: 
2) Hamming Distance: 
3) FEC: 
4) Busy Hour:
5) Stop-and-Wait:
6) Checksum:
7) WDM:
8) T1:

Short Answer:
9) Describe what happens as a cell phone moves from one cell to another.

10) How many trunks lines are needed to support 200 Homes? 
Given - 1.7 phones per home average. Blocking Factor of 1%.
Busy hour is 4.1 CCS for the first line in a home, and 2.3 CCS for the second line. 
Use Erlang B. Show all work and include reference to which online calculator you use. 

11) Compare the use of CRC-8 and BIP-8 for error detection.  
Which gives better detection of bit errors, of large and small burst errors and why?
If the system is transmitting real-time data which can not be retransmitted which is better and why?
If the system can retransmit a block of data which is better and why?

12) Given a tranmission line that is running at 1.544Mbps.  
A BIP-8 check code is inserted every 1000 bytes. 
Over the course of 1 minute, the BIP-8 checker detects 100 parity errors.
What is the BER of that line?
Show all work and document all assumptions.


13) Compare a Go-back-N Error control mechanism with selective reject error control mechanism.