Homework #2 - CSIS 625 - Fall 2002 - Section 1
Due Week 6 (Oct 14, 2002) 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.

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:
9) HDLC:

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

11) How many trunks lines are needed to support 500 Homes? 
Given - 1.3 phones per home average. Blocking Factor of 1%.
Busy hour is 3.7 CCS for the first line in a home, and 2.8 CCS for the second line. 
Use Erlang B. Show all work and include reference to which online calculator you use. 

12) 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?


13) 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 10000 parity errors.
What is the BER of that line?
Show all work and document all assumptions.


14) Compare a Go-back-N Error control mechanism with a selective reject error control mechanism.
How are the similar, and how are the different?  What are strengths and weaknesses of each?