S-07S-07

Towards using 900 MHz for Wireless IEEE 802.11 LANs

Measurements in an Indoor Testbed

Assigned to: Moritz Grauel, Mathias Naber

Advisor: Mathias Kurth

Submission: March 2008

Paper available at: http://www.informatik.hu-berlin.de/~naber/paper.pdf

Problem Statement

To explore further use cases for wireless mesh networks – evading congested frequency bands is required. Achieving soft real time or simply bridge larger distances – the require- ments simply exceed the physical specifications given by today’s IEEE 802.11 networks. Some saw their opportunity to modify existing IEEE 802.11 hardware to operate at dif- ferent frequency bands. How to determine possible improvements?

The “Wireless Testbed Framework” is a set of tools to ease and automate testing and evaluating of new hardware in an existing, experimental wireless mesh network. It is targeted to small and embedded devices running openWRT or similar embedded Linux variants. The main purpose is to manage measurement scripts and schedule the execution of those scripts as well as to collect the measurement results. Many measurements on wireless link performance have been made. We present link performance results – comparing different frequency bands at 900 MHz, 2400 MHz and 5000 MHz – performed with our automated measurement framework. The Ubiquity SR9 900 MHz WiFi adapter is compared to off the shelf WiFi hardware. The link quality and the bit error patterns of the different frequencies are analyzed and compared to each other.

Deliverables

Our plan is to develop a modular framework which allows easy measurement of wireless links independent from used hardware.

Prior Art

There was a lot of research about 2.4GHz and 5GHz WLANs which explored neary everything. It showed, the used frequency isn't ideal for the desired task.

At this moment, the new 900MHz is still not widespread and shows some great potential.

Key Ideas / Project Execution Plan

- paper-work

Project Log

- tried some different MadWifi-drivers - basic ping measurements (packet loss, round trip time, ...)