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The source code is too long to be put on this web page. You will have to download it. Open source_code/iar_v4.11/lab_ezwsn.eww with IAR. The project corresponding to this section is called txrx_wsn .

Project txrx_wsn is a complete WSN example which implements a complete communication stack for WSNs, using gradient multi-hop routing. A gradient routing protocol assigns a scalar value to each node, which we call its height . Heights are assigned in such a way that they increase with distance to a central node. Distance is calculated using a cumulative cost function based here on hop count. The forwarding process selects the next hop as the neighbor which offers the largest gradient, i.e.the neighbor with lowest height.

In the implemented protocol stack, the application layer generates sensed data to be sent to a sink node, by using on-board Analog-to-Digital Conversion. The routing layer is responsible for updating the node's myHeight ; the MAC layer performs on-demand neighbor discovery and uses preamble sampling for energy-efficiency.

The execution timeline of the implemented protocol is presented in the figure below, for an example topology of 3 nodes. By default, nodes perform preamble sampling. When a node wants to send a message (here A ), it starts by sending a preamble as long as the check interval ( CI ) to make sure all neighbors hear that preamble. For efficient handling by a packet radio, the preamble is cut into a series of micro-frames UF , each containing a counter indicating the number of UF still to come. Upon hearing a UF , a receiving node turns its radio off and sets a timer to switch into receive mode after the last UF . At that moment, the sender indicates the duration of the neighbor announcement window to follow in a CW packet.

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Timeline illustrating the execution of the protocol stack. The x-axis represents time; a box above the line indicates that the radio is transmitting; a gray/white box under the axes means that the radio in receiving/idle listening, resp.; no box means the radio is turned off.

Receivers choose a random backoff for sending an ACK message inside the neighbor announcement window and sleep the rest of the time; the sender listens for the complete announcement window and populates the initially empty neighbor table as it receives ACK messages.

After the neighbor announcement window, the sender updates its myHeight by the minimum value of its neighbors', incremented by one, and select its neighbor with smallest Height . It inserts this information into the DATA packet header which it transmits. The destination node receives the whole packet while the non-destination neighbor switches to sleep after the header. The destination replies with a final acknowledgment FIN ; all nodes resume preamble sampling.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Ezwsn: experimenting with wireless sensor networks using the ez430-rf2500. OpenStax CNX. Apr 26, 2009 Download for free at http://cnx.org/content/col10684/1.10
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