TLEN 5520/ECEN 5032, Wireless Data Networks

TLEN 5520/ECEN 5032 - Wireless Data Networks

Martin Heusse, Spring 2009

Homeworks

Homework 1 Due january 23d.
Solution to Homework 1, useful for HW2!
Homework 2 Due feb. 4th.
Solution to homework 2 (There was an error in the previous table, which is now corrected…)
Homework 3 Due feb. 11th.
Solution to Homework 3
Homework 4 Due feb. 18th.
Solution to homework 4
Lab 1 Due feb. 25th.
Lab 2 Due april. 15th.
Lab 3 Due april. 22nd.

Midterm solution

Midterm — solution

How to connect a FreeBSD to the UCB network ?

If you are starting from scratch, just associate your wireless interface to the UCB net. (ifconfig ath0 SSID "UCB Wireless" up)
Then configure using DHCP (dhclient ath0)
You are ready to go! (Provided your MAC address is known by UCB Wireless…)
You can use scp or sftp to upload files to a server…

Homework Policy You are encouraged to work with others on the homeworks with the following caveats.

Caveat 1: You write your own solutions.

Caveat 2: The top of your homework lists all the other students with whom you collaborated on the assignment.

Projects

Here are a few examples that you can consider to write your project proposal. You are not expected to just pick one of these subjects, but they can guide you.

Auto rate adaptation
There are various methods cards may use to find the (best) rate they should use for transmissions. After showing how this works in the presence of noise or attenuation, you will criticize (or not…) the various available methods.
Security
The WEP encryption mecanism is known for being weak. Still, one can wonder how long it takes sniffing traffic or sending froged frames before WEP surrenders (e.g. is it possible to crack it with if there is very little traffic).
Another related problem is to check if the cards have sufficient computation power to encrypt/decrypt traffic at the highest transmission rates.
New standards
Assess the performance obtained with the latest cards (11n); How much traffic can be sent and how far; at what cost?
Low cost internet access
Map a neighborhood for open APs, check the performance obtained. What software would allow quick handoffs from one AP to the next…
802.11e
802.11e is implemented in most cards. It allows QoS differentiation at the MAC layer, but it is very rarely used. Why? And how is it possible to actually use it on a choice of platforms. Then what does it effectively bring?
Propagation in unexpected waveguides
What kind of performance can you expect when using e.g. ventilation pipes as a communication medium? They could be decent waveguide…
802.11k
interferences
Look at the real interference range for various modulations, PHY layers.