Hi,
Have you tried to plot the received power of node1 against the distance to
node0? I think that an exponent equal to 2.5 for the log-distance pathloss
model could allow the signal to reach long distances. If despite of the
Ricean fading your average received power is always very high, you will
receive all packets correctly, since you are using a quite high value of K. Try
also to compare the simulation with the theoretical propagation model
equations .
Regards
Miguel
Víctor González <[EMAIL PROTECTED]> escribió:
Hi all,
we are simulating a wireless scenario with NS2.29 in an Ubuntu 6.06LTS
(i686 arch). Our scenario consists in two mobile nodes moving at high
speeds in a highway scenario. Each node moves towards the other and we
achieve relative speeds up to 300Kmph (186mph) and uses a 802.11b
wireless interface. One of them sends CBR packets at 11Mbps to the
other.
We are using the Ricean Propagation Model Extension (made by Ratish J.
Punnoose) in order to have a more realistic propagation model than
TwoRayground or Shadowing.
When we analyzed the trace file we haven't any errors (in MAC level).
All the packets sent bye node 0 were received by node 1. We expected to
have some losses in our system, so after seeing this we have installed
an error model (Ralistic Channel Propagation, made by Wu Xiuchao), which
introduces errors due BER. Despite adding that error model we still
haven't lost packets in our tracefile. We also tried to simulate without
the extensions we mentioned previously with the same result.
We think this is a very strange situation, may be, produced by some
mistake in our NS2 script. You can see it below.
Thanks to all and kind regards,
Víctor González Pacheco
# ===========================================
# Arguments passed to the Simulation Script
# ===========================================
set HI [lindex $argv 0]
set SPEED [lindex $argv 1]
set TRACE_NAME [lindex $argv 2]
set NAMTRACE_NAME [lindex $argv 3]
set STOP [lindex $argv 4]
set SPEED [expr $SPEED/3.6] ;# Changing speed from Km/h to
m/s
set RATE [lindex $argv 5]
set SIZE [lindex $argv 6]
# ============================================
set ns_ [new Simulator]
# ======================
# Import Node Options
# ======================
# Options for NS2 simulations in COM2REACT project.
# For more information please contact with [EMAIL PROTECTED]
# ==============================================
# first set values of shadowing model
# ==============================================
Propagation/Shadowing set pathlossExp_ 2.5 ;# path loss
exponent
Propagation/Shadowing set std_db_ 4.0 ;# shadowing
deviation (dB)
Propagation/Shadowing set dist0_ 1.0 ;# reference
distance (m)
Propagation/Shadowing set seed_ raw ;# seed for RNG
# ==============================================
# ===============================================
# Define Options
# ===============================================
set opt(chan) Channel/WirelessChannel ;# channel type
#set opt(prop) Propagation/TwoRayGround ;#
radio-propagation model
#set opt(prop) Propagation/Shadowing ;#
radio-propagation model
set opt(prop) Propagation/Ricean ;#
radio-propagation model
set opt(netif) Phy/WirelessPhy ;# network
interface type
set opt(mac) Mac/802_11 ;# MAC type
set opt(ifq) Queue/DropTail/PriQueue ;# interface
queue type
set opt(ll) LL ;# link layer
type
set opt(ant) Antenna/OmniAntenna ;# antenna
model
set opt(ifqlen) 100 ;# max packet
in ifq
set opt(nn) 2 ;# number of
mobilenodes
set opt(adhocRouting) OLSR ;# routing
protocol
set opt(cp) "traffic_pattern.tcl" ;# connection
pattern file
set opt(sc) "node_movements.tcl" ;# node
movement file.
set opt(x) 4000.0 ;# x coordinate
of topology
set opt(y) 100.0 ;# y coordinate
of topology
set opt(seed) 0.0 ;# seed for
random number gen.
set opt(stop) $STOP ;# time to stop
simulation
set opt(v0) $SPEED ;# Node v0
speed in m/s
set opt(v1) 0.0 ;# Node v1
speed in m/s
# ================================================
# ================================================
# Energy options
# ================================================
#set opt(engmodel) EnergyModel
#set opt(txPower) 1.4 ;# transmitting
power in mW 1.4
#set opt(rxPower) 0.9 ;# recving
power in mW
#set opt(sensePower) 0.00000175 ;# sensing power
in mW
#set opt(idlePower) 0.0 ;# idle power
in mW
#set opt(initeng) 75 ;# Initial
energy in Joules
# =================================================
# ======================
# Turn off RTS/CTS
# ======================
Mac/802_11 set RTSThreshold_ 3000
# ======================
# ===================================================
# Initialize the SharedMedia interface with parameters to make
# it work like the 5004 MP Atheros 4G miniPCI card
# ===================================================
Phy/WirelessPhy set CPThresh_ 10.0 ;#
Collision Threshold
Phy/WirelessPhy set CSThresh_ 2.0e-14 ;#
(-107dBm)
Phy/WirelessPhy set RXThresh_ 1.77827941e-13 ;#-97.5 dBm
Phy/WirelessPhy set Pt_ 0.4 ;#
0.031622777 Transmition Power (watts)
Phy/WirelessPhy set freq_ 2.472e9 ;# Frequency of
work
Phy/WirelessPhy set L_ 1 ;# System
Loss Factor
# ===================================================
# =========================
# control OLSR behaviour from this script -
# =========================
Agent/OLSR set use_mac_ true
Agent/OLSR set debug_ true
#Agent/OLSR set willingness 3
Agent/OLSR set hello_ival_ $HI
#Agent/OLSR set tc_ival_ 5
# ============================================
#===============================================
# UPDATE OPTIONS
#================================================
ErrorModel80211 noise1
-107 ;# 1Mbps datarate thermal
noise
ErrorModel80211 noise2
-106 ;# 2Mbps datarate thermal
noise
ErrorModel80211 noise55 -105 ;#
5.5Mbps datarate thermal noise
ErrorModel80211 noise11 -102 ;#
11Mbps datarate thermal noise
ErrorModel80211 shortpreamble 0 ;#
toggle 802.11 short preamble on/off
ErrorModel80211 LoadBerSnrFile ber_snr_intersil.txt ;# use
Intersil BER/SNR empirical curves
#ErrorModel80211 LoadBerSnrFile ber_snr_choi.txt ;# use
theoretical curves from del Prado
;# Pavon
and Choi, "Link Adaptation Strategy
;# for
IEEE 802.11 WLAN via Received Signal
;#
Strength Measurement"
Mac/802_11 set CWMin_ 31
Mac/802_11 set CWMax_ 1023
Mac/802_11 set SlotTime_ 0.000020 ;# 20us
Mac/802_11 set SIFS_ esto 0.000010 ;# 10us
Mac/802_11 set PreambleLength_ 144 ;# 144 bit
Mac/802_11 set ShortPreambleLength_ 72 ;# 72 bit
Mac/802_11 set PreambleDataRate_ 1.0e6 ;# 1Mbps
Mac/802_11 set PLCPHeaderLength_ 48 ;# 48 bits
Mac/802_11 set PLCPDataRate_ 1.0e6 ;# 1Mbps
Mac/802_11 set ShortPLCPDataRate_ 2.0e6 ;# 2Mbps
Mac/802_11 set RTSThreshold_ 3000 ;# bytes
Mac/802_11 set ShortRetryLimit_ 7 ;#
retransmissions
Mac/802_11 set LongRetryLimit_ 4 ;#
retransmissions
Mac/802_11 set newchipset_ false ;# use new
chipset, allowing a more recent
;#
packet to be correctly received in place
;#
of the first sensed packet
Mac/802_11 set dataRate_ 11Mb ;# 802.11 data
transmission rateMac/802_11 set basicRate_
1Mb ;#
802.11 basic transmission rate
Mac/802_11 set aarf_ true ;# 802.11
Auto Rate Fallback
# ===================================================
# ========================
# only for Ricean propagation
# ========================
set prop_inst [$ns_ set propInstance_]
$prop_inst MaxVelocity 80.0;
$prop_inst RiceanK 6;
$prop_inst LoadRiceFile "rice_table.txt";
# ========================
---------------------------------
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