Projects
Bootstrapping/Discovery
Evaluation using ORBIT
The control protocols for cognitive
radio networks are implemented using C++ as an network
application in Linux. Specifically, the bootstrapping
protocol sends periodical beacons using raw IEEE 802.11
packets. The discovery protocol calculates local link states
by estimating direct link qualities from bootstrapping
beacons. End-to-end path is discovered for each nodes to
learn about the whole network.
The experiments are conducted in
the 20x20 ORBIT radio grid. Each node is equipped with two
wireless interface, one is used for control protocols and
the other is used to transmit data. Nodehandler is used to
start the protocol application at each node. Perl scripts
are used to collect trace files and dynamically debug each
available wireless node.
Spectrum Sensor Demo System
This demo is designed to work with the routing demo for
sensor networks. In the spectrum sensor part, main work is
to setup a sensor part – “spectrum sensor” and a console
part with 3D ability to show the data. Both the separate two
parts seem working but now it is lack of co-testing with
routing algorithms.
There are some points obtained during debugging:
(a) The data (statistics collected when scanning channels 1
to 8) is packaged and send out to the direct associated
parent after association completion. This can be also
modified to send every couples of seconds if there is a
valid association with this sensor node.
(b) There is a lagging problem for the sensed data (signal
strength). All data in different channel seems correlated
and does not vary too much. When links are down, the sensed
strength can not go down very fast, and this may be due to
the control of AGC in the transmitter? It is also suggested
to stay longer (more than several seconds) in each channel
and then sense the statistics data.
(c) In the console, a 3D figure is drawn for the position {x,y}
vs. Signal strength (dBm). The position is actually
relative position coordinate, for example, {x,y} are started
from 00, ...., to 44, which has 5x5=25 values. (If there are
less sensors, intermediate values can be estimated.) Default
values is -80dBm and usually the signal strength for a
transmitting radio is -40dBm (sensed value).
Spectrum Etiquette Protocol Implementation in WLAN-BT Scenarios
Proof-of-concept experimental results for a CSCC
implementation are presented for an example scenario in
which multiple nearby 802.11b and Bluetooth devices contend
for 2.4 GHz ISM band access. Large file transfer and
session-based data services are tested and results show
system performance based on throughput and delay is
improved.
Spectrum Etiquette Demo System
The SE demo is designed to show the basic idea about
spectrum etiquette protocols. The demo is setup in pairs up
to 4 or 5 pairs, with 2 bluetooth pairs and 2 or 3 WLAN
pairs. The demo will be added a spectrum measurement
console, which can show the dynamic power spectrum in the
ISM band. And thus interference between DS and FH radios
are shown clearly.
(1)
cscc_wlan: in this part, basic CSCC protocol is
implemented by IEEE 802.11 prototype. 802.11 devices are
using one wireless card to broadcast CSCC messages every 2
seconds in channel #1, and exchange UDP data in another two
channels (#6 and #11). UDP data is geneated as a session
(~1000 packets with length ~1500Bytes each) randomly.
(2)
cscc_bt: This is for the bluetooth device with a
802.11 wireless card for CSCC (dual card). Only CSCC
messages are broadcast through the 802.11 card. Bluetooth
data session is also randomly generated, as a format of echo
datagram (random length upto 1024 Bytes, random packet
numbers). Note that Bluetooth data will consume the whole
spectrum band for frequency hopping. So we can control
through priority and price bid to decide wehether cscc_wlan
should give up the spectrum demond to Bluetooth or vice
versa.
(3)
cscc_con: This is a java console running in the same
machine as cscc_bt. Because in cscc_bt, 802.11 radio do not
need to switch to different channels, we can monitor the
traffic pattern through this radio. This console is designed
as our lab plan, and currently 802.11 traffics in ch#6 and
#11, and CSCC messages in ch#1 can be monitored runtime (
with a little response delay due to the refresh interval).
The console is refresed every 1 second to draw what’s
happening in the whole ISM band.
Spectrum Coordination Lab Design
- Forwarding nodes with Bluetooth USB card
(Ericsson USB APtK) can communicate pear to pear.
- Forwarding nodes with Bluetooth PCMCIA
card (Xircom Creditcard) can communicate pear to pear.
Integration of Bluetooth card in forwarding node
To support multi-devices in our sensor network,
bluetooth wireless card is integrated into the forwarding
node, by which small sensors with bluetooth wireless
interface can access the sensor network. Data or voice can
be carried through the wireless connection, and then
forwarded to the bluetooth access point, or forwarded by the
multi-interface forwarding node to the WLAN network.
Technical approaches: Bluetooth PCMCIA card and USB
card driver and bluetooth service stack driver are compiled
as kernel modules with the linux kernel version 2.4.18.
Bluez
protocol stack is used and tested.
Status: Data link (ACL) and voice link (SCO) through
L2CAP layer can be setup between bluetooth devices in the
forwarding nodes. Bluetooth WPAN with Access Point Gateway
is being tested.
IEEE 802.11 Sniffer for Access Point
The project involves micro-system using Linux kernel
2.4.18. IEEE 802.11 sniffer is implemented into the small
Linux system, running in Access Points. OpenAP and libpcap
packages are used for the implementation. Packets through
the AP can be captured and analyzed for laboratory and
measurement purposes. | 
