Visual Sense a wire less simulator Introduction

2010-11-28T05:09:00.001-08:00

Visual Sense an PTOLEMY Open Source Project for wireless Simulator, whose back end is controlled by java.

Some of practicals done on it including CSMA/CA, Power Loss, Channel Utilization and throughput can be provided by me on request....just post your email address.

Modeling of wireless sensor networks requires sophisticated modeling of communication channels, sensor channels, ad-hoc networking protocols, localization strategies, media access control protocols, energy consumption in sensor nodes, etc. This modeling framework is designed to support a component-based construction of such models. It is intended to enable the research community to share models of disjoint aspects of the sensor nets problem and to build models that include sophisticated elements from several aspects.

Download visual sense from http://ptolemy.berkeley.edu/download/index.htm
Also required jdk before instalation so get it from http://www.oracle.com/technetwork/java/javase/downloads/jdk6-jsp-136632.html
Steps- First install java.
Second install visual sense
as it ask for jdk path provide it the path in your system, in my system i give it as
C:\Java\jdk1.6.0_06

Authors Published Work in Visual Sense

1) http://www.ijcse.com/docs/IJCSE11-02-03-149.pdf

2) ...

INTRODUCTION
Starting with Visual Sense by Making Connections
First step is to generate input and view them on output screen, hence we learn some steps to generate some different types of inputs and watch out them on screen.

1) File>New>Graph Editor
In left pane move to Actor>Sources>Timed Sources(for generating input)
Actor>Sink>Display(for watching output).

2)Using Expressions
The expression evaluation is very important to generate different inputs.
Actor>Math>Expression

3)Connecting wireless components, by using wireless channel.

Experiment No 1

Design an 802.11 network of mesh topology, using set of suitable input check the performance parameters like:

Battery Energy Consumed,

Bit Error Rate

Busy Signal to Noise Ratio

Throughput Utilization

BER

The bit error rate or bit error ratio (BER) is the number of bit errors divided by the total number of transferred bits during a studied time interval. BER is a unitless performance measure, often expressed as a percentage number.

As an example, assume this transmitted bit sequence:

0 1 1 0 0 0 1 0 1 1,

and the following received bit sequence:

0 0 1 0 1 0 1 0 0 1,

The number of bit errors (the underlined bits) is in this case 3. The BER is 3 incorrect bits divided by 10 transferred bits, resulting in a BER of 0.3 or 30%.

SNR

In analog and digital communications, signal-to-noise ratio, often written S/N or SNR, is a measure of signal strength relative to background noise. The ratio is usually measured in decibels (dB).

If the incoming signal strength in microvolts is V_s, and the noise level, also in microvolts, is V_n, then the signal-to-noise ratio, S/N, in decibels is given by the formula

S/N = 20 log₁₀(V_s/V_n)

If V_s = V_n, then S/N = 0. In this situation, the signal borders on unreadable, because the noise level severely competes with it. In digital communications, this will probably cause a reduction in data speed because of frequent errors that require the source (transmitting) computer or terminal to resend some packets of data.

Ideally, V_s is greater than V_n, so S/N is positive. As an example, suppose that V_s = 10.0 microvolts and V_n = 1.00 microvolt. Then

S/N = 20 log₁₀(10.0) = 20.0 dB

which results in the signal being clearly readable. If the signal is much weaker but still above the noise -- say 1.30 microvolts -- then

S/N = 20 log₁₀(1.30) = 2.28 dB

Experiment No 2

Design wireless network, using carrier sensing multiple access technique check the performance like parameter

Channel Throughput

Signal to Noise Ratio

Carrier Sense Multiple Access (CSMA) is a probabilistic Media Access Control (MAC) protocol in which a node verifies the absence of other traffic before transmitting on a shared transmission medium, such as an electrical bus, or a band of the electromagnetic spectrum.

"Carrier Sense" describes the fact that a transmitter uses feedback from a receiver that detects a carrier wave before trying to send. That is, it tries to detect the presence of an encoded signal from another station before attempting to transmit. If a carrier is sensed, the station waits for the transmission in progress to finish before initiating its own transmission.

"Multiple Access" describes the fact that multiple stations send and receive on the medium. Transmissions by one node are generally received by all other stations using the medium.

Carrier sense multiple access with collision avoidance (CSMA/CA), in computer networking, is a wireless network multiple access method in which:

a carrier sensing scheme is used.
a node wishing to transmit data has to first listen to the channel for a predetermined amount of time to determine whether or not another node is transmitting on the channel within the wireless range. If the channel is sensed "idle," then the node is permitted to begin the transmission process. If the channel is sensed as "busy," the node defers its transmission for a random period of time. Once the transmission process begins, it is still possible for the actual transmission of application data to not occur.

CSMA/CA is a modification of carrier sense multiple access.

Collision avoidance is used to improve CSMA performance by not allowing wireless transmission of a node if another node is transmitting, thus reducing the probability of collision due to the use of a random truncated binary exponential back off time.

Throughput

In communication networks, such as Ethernet or packet radio, throughput or network throughput is the average rate of successful message delivery over a communication channel. This data may be delivered over a physical or logical link, or pass through a certain network node. The throughput is usually measured in bits per second (bit/s or bps), and sometimes in data packets per second or data packets per time slot.

The system throughput or aggregate throughput is the sum of the data rates that are delivered to all terminals in a network.

The throughput can be analyzed mathematically by means of queueing theory, where the load in packets per time unit is denoted arrival rate λ, and the throughput in packets per time unit is denoted departure rate μ.

Throughput is essentially synonymous to digital bandwidth consumption.

For consulting author check learningsubway.com.

To check youtube

Wireless Simulation by Visual Sense Ptolemy 2

Visual Sense a wire less simulator Introduction