/************************************************************************************
*
* File: readme.asn
*
* Author: Adnan Abu-Mahfouz
*
* Date: October 2013
*
* Description: Localisation system in wireless sensor networks using ns-2
************************************************************************************/
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1. Introduction:
ns-2 contains several flexible features that encourage researchers to use ns-2 to investigate the characteristics of wireless sensor networks (WSNs). However, to implement and evaluate localisation algorithms, the current ns-2 version (ns-2.35) should be extended and new modules should be added.
In this file, we will show how to add the new modules and also to modify some of the existing files. The following article explains this extension:
A. M. Abu-Mahfouz and G. P. Hancke, GP., “ns-2 extension to simulate localization system in wireless sensor networks,” In Proceedings of the IEEE Africon 2011 conference, 13-15 September , Livingstone, Zambia, 2011, pp. 01-07. http://researchspace.csir.co.za/dspace/handle/10204/5559
The reader can also be referred to the following PhD thesis, for further details about the localisation system in general (chapter two) and the implementation (chapter three).
Abu-Mahfouz, AMI 2011, Accurate and efficient localisation in wireless sensor networks using a best-reference selection, PhD thesis, University of Pretoria, Pretoria, http://upetd.up.ac.za/thesis/available/etd-10122011-124534/
Please note that, I will refer to directory /ns-allinone-2.35/ns-2.35 as ~ns
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2. Guidelines for extending ns-2:
The tar file named "ns2_localisation.tar.gz" contains the earlier version for ns-2.34. Therefore, if you are using ns-2.35 then there is no need to download this file.
The newer version For ns-2.35, is in the folder named "ns-2.35_Localisation, which include the following:
- "new" directory (16 files): which contains the new files
- "modified" directory (10 files): which contains the modified files
- "tcl-examples" directory (6 files): which contains a few tcl example files that using the new localisation system
- installation guidelines: shows how to install ns-2.35, if you did not do that yet.
- readme.asn file: the current file
Follow these steps to be able to simulate localisation system:
a. If you did not install ns-2 yet, follow the instructions shown in the “installation guidelines” to install it. Make sure it is working probably.
b. Create a new directory “location” in ~ns. Download all the files (16 files) from the "new" directory and save them in the "location" directory
c. Modify the following files as shown in Section 5 “Modified files”
--------------------------------------------------------
| Directory | Modified files |
--------------------------------------------------------
| ~ns/common/ | packet.h |
| ~ns/common/ | mobilenode.h |
| ~ns/common/ | mobilenode.cc |
| ~ns/common/ | location.h |
| ~ns/tcl/lib/ | ns-packet.tcl |
| ~ns/tcl/lib/ | ns-default.tcl |
| ~ns/tcl/lib/ | ns-lib.tcl |
| ~ns/tcl/lib/ | ns-node.tcl |
| ~ns/tcl/lib/ | ns-namsupp.tcl |
--------------------------------------------------------
d. Open "~ns/Makefile" and add the following:
Under INCLUDES= add the new directory, in the last line add " \" then enter. then add:
-I./location
Under OBJ_STL add the corresponding object files names of the new modules (again do not forget to add " \" then enter befor adding the new lines)
location/locationrequest.o \
location/locationresponse.o \
location/locationdiscovery.o \
location/mmse.o \
location/position.o \
location/nearestposition.o \
location/refineposition.o
e. OPTIONAL (this step can be done later after you successfully test the new localisation system):
i. In order to stop the continuous printing of the receiving power at the terminal, which increasing the running time especially if you would like to run the simulation for long time, you can simply do the following:
- Open the file ~ns/mobile/propogation.cc
- Within the FreeSpace::Pr( ) function, comment the following line
// printf("%lf: d: %lf, Pr: %e\n", Scheduler::instance().clock(), d, Pr);
ii. In order to stop logging the energy of the node into the trace file, do the following:
- Open the file ~ns/common/mobilenode.cc
- Comment the entire body of log_energy() function
f. Open a terminal in Accessories/Terminal. Then cd ns-allinone-2.35/ns-2.35, then run make. (Note: if you get some errors just run make clean then make)
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3. Simulating localisation system
Using the ns-2 extension does not require new knowledge or writing a specific code to run the simulator. Normal users who have the basic knowledge to run a simple wireless network using ns-2 are able to write a simple Tcl script to simulate the proposed localization system. However, if you find any difficulty to understand how localisation system has been configured and used in these files you can refer to the two references mentioned early. If you are new to ns-2 you can refer to the following reference for some tutorials about configuring wireless networks.
"The network simulator - ns-2," 12 February 2010, http://nsnam.isi.edu/nsnam/index.php/User_Information.
Six tcl examples can be found under the directory “tcl-examples”. At the beginning of each files you can find how to run it.
To execute any of the first three files loc1.tcl, loc2.tcl or loc3.tcl you can use the following command syntax:
ns filename METHOD
METHOD: is representing the localisation method that will be used in the estimation, an integer value of 1,2 or 3 can be used to consider one of the following localisation methods: general(1), nearest3(2), refine(3)
For example, to execute the first file using the general localisation algorithm, you can run the following command:
ns loc1.tcl 1
To execute the other tcl files; loc4.tcl, loc5.tcl or loc6.tcl, one extra argument should be included in the command syntax:
ns filename SEED METHOD
SEED: is the seed value used by RNG (0, 1, 2,...). This argument is used to specify where the nodes will be distributed, which allows evaluating the localisation algorithm considering different nodes distribution. If you comparing different localisation algorithms the same value(s) of SEED should be used (except the value of 0).
For example, to execute the fifth file using the nearest localisation algorithm, you can run the following command:
ns loc5.tcl 1 2
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4. Traced location data:
The format of the traced data will be as follows:
L 13.845754 3 0.499617 5 0.725425 45.353581 44.919124
| time node energy | error X and Y coordination for estimated position
| |
L is for Location # of used references
You can simply use the grep command to filter only the location information form the trace file. Assuming the name of the trace file is “location.tr”, then the extracted location information can be store in the file named “result” by using the following command:
grep "^L" location.tr > result
This command means filter only those lines that begin with the letter L
/**********************************************************************************************************************************************************/
5. Modified files:
This section shows the modifications that have been done to the existing files. You can also refer to the files in “modified” directory to see exactly how these modifications have been done.
/*========~ns/common/packet.h===============================================================================================*/
Add:
#define HDR_LOCREQ(p) (hdr_locreq::access(p)) //location request
#define HDR_LOCRES(p) (hdr_locres::access(p)) //location response
Before the PT_NTYPE add the following two packet types.(please note that these values (i.e. 73 and 74) could be different based on the value of PT_NTYPE. in our case the value of PT_NTYPE was 73. therefore I used the valuses of 73 and 74 then modify PT_NTYPE to 75)
// Location request and response packets
static const packet_t PT_LOCREQ = 73; //where 73 was the current value of PT_NTYPE
static const packet_t PT_LOCRES = 74;
Modify the value of PT_NTYPE
static packet_t PT_NTYPE = 75; // This MUST be the LAST one
Inside the function initName() of class p_info add:
// location request and response
name_[PT_LOCREQ] = "locreq";
name_[PT_LOCRES] = "locres";
/*==========================================================================================================================*/
/*========~ns/common/mobilenode.h===========================================================================================*/
Add the following:
inline Topography* get_topography() { return T_;}
// log the location information
void log_loc(double, int, double, double);
/*==========================================================================================================================*/
/*========~ns/common/mobilenode.cc==========================================================================================*/
Add the following function to log the location information
void
MobileNode::log_loc(double error_, int no_ref_, double x, double y)
{
if (!log_target_)
return;
Scheduler &s = Scheduler::instance();
sprintf(log_target_->pt_->buffer(),"L %f %d %f %d %f %f %f",
s.clock(),
address_,
energy_model_->energy(),
no_ref_,
error_,
x,
y);
log_target_->pt_->dump();
}
/*==========================================================================================================================*/
/*========~ns/common/location.h=============================================================================================*/
Add a null constructor
Location(): X(0), Y(0), Z(0) {}
Add the getters and setters of individual parameters
virtual double getx() {return X;}
virtual double gety() {return Y;}
virtual double getz() {return Z;}
virtual void setx(double x) {X = x;}
virtual void sety(double y) {Y = y;}
virtual void setz(double z) {Z = z;}
Add the following function to check if two locations are the same
virtual int is_equal(Location *loc)
{
if((X == loc->X) && (Y == loc->Y) && (Z == loc->Z))
return 1;
else
return 0;
}
Add the following function to estimate the distance between two locations
virtual double distance(Location *loc)
{
double dx = X - loc->X;
double dy = Y - loc->Y;
double dz = Z - loc->Z;
return sqrt( dx * dx + dy * dy + dz * dz);
}
/*==========================================================================================================================*/
/*========~ns/tcl/lib/ns-packet.tcl=========================================================================================*/
At the end of protolist {} add
LocReq #Location Request
LocRes #Location Response
/*==========================================================================================================================*/
/*========~ns/tcl/lib/ns-default.tcl========================================================================================*/
Add the following to the end of the file:
#Location discovery
Agent/LocReq set packetSize_ 100
Agent/LocRes set packetSize_ 100
Application/LocDiscovery set distanceError_ 0 ;# considering distance measurement error, enable(1) or disable (0)
Application/LocDiscovery set random_ 0
Application/LocDiscovery set reqFreq_ 5.0 ;# every 5.0 sec
Application/LocDiscovery set maxRequests_ 268435456 ;# 0x10000000
Application/LocDiscovery set showColor_ 1 ;# Node colouring, enable(1) or disable(0)
Application/LocDiscovery set method_ 1 ;# Localisation algorithm, general method (1), nearest3(2), refinement(3)
Simulator set attribute_ ""
/*==========================================================================================================================*/
/*========~ns/tcl/lib/ns-lib.tcl============================================================================================*/
Add to # New node structure
# added here to specify node attribute (beacon, reference or unknown)
# -attribute BEACON/REFERECE/UNKNOWN
Add the following instproc
#used for location discovery process
Simulator instproc attribute {val} {$self set attribute_ $val}
Within Simulator instproc node-config args, add the following instvar
#Location discovery
attribute_
Within Simulator instproc create-wireless-node args, add the following instvar
#Location discovery
attribute_
Also add:
#location discovery
if [info exists attribute_] {
$node set nodeAttribute_ $attribute_
}
/*==========================================================================================================================*/
/*========~ns/tcl/lib/ns-node.tcl===========================================================================================*/
Within Node instproc init args, add the following instvar
#Location discovery
nodeAttribute_
Add the following instproc
#Location discovery
Node instproc attribute {} {
return [$self set nodeAttribute_]
}
/*==========================================================================================================================*/
/*========~ns/tcl/lib/ns-namsupp.tcl========================================================================================*/
Modify Node instproc color as following
#enable changing the node's color after running the simulator by Ian Downard
Node instproc color { color } {
$self instvar attr_ id_
set ns [Simulator instance]
set attr_(COLOR) $color
set attr_(LCOLOR) $color
if [$ns is-started] {
# color must be initialized
$ns puts-nam-config \
[eval list "n -t [$ns now] -s $id_ -S COLOR -c $color -o $attr_(COLOR) -i $color -I $attr_(LCOLOR)"]
}
}
/*==========================================================================================================================*/
