Simulation-of-GPRS-MS-BS-Interface-Using-Ns-network-SimulatorGPRS-MS-BS接口使用NS网络仿真器的仿真ppt课件

,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Simulation of GPRS MS-BS Interface Using,ns,-Network Simulator,Dual Degree Presentation,by,Richa Jain(96D07007),Department of Electrical Engineering,Indian Institute of Technolgy,Mumbai,India.,Simulation of GPRS MS-BS Inte,1,Outline,Introduction to GPRS,About,ns,-Network Simulator,Scope of the Project,Implementation details,Experiments,Concluding remarks.,Outline Introduction to GPRS,2,The General Packet Radio Service,Packet switched radio transmission,Suited for bursty applications(eg Internet),Data rates upto 170 kbps,Re-uses GSM resources,Lower call set-up times;cheaper,The General Packet Radio Servi,3,GPRS Architecture,GPRS Architecture,4,GPRS Protocol Stack,GPRS Protocol Stack,5,About,ns,Public domain,Event driven simulator,Split language OTcl and C+,Nodes and links;routing algorithms;queuing schemes,Protocols TCP,UDP,IP,Traffic generators CBR,Exponential,Pareto,Basic mobility support,.,About nsPublic domain,6,A simple,ns,script,set ns new Simulator,#Creating two nodes,set n0$ns node;set n1$ns node,#Creating a link btwn the nodes;prop delay=10ms;Drop tail.,$ns duplex-link$n0$n1 1Mb 10ms DropTail,#Nodes themselves dont send/rx data.Create an agent to do so,set cbr0 new Agent/CBR,$ns attach-agent$n0$cbr0,#create sink,set null0 new Agent/Null,$ns attach-agent$n1$null0,#connect the two agents,$ns connect$cbr0$null0,#Tell cbr0 when to start and stop,$ns at 0.5$cbr0 start,$ns at 4.5$cbr0 stop“,$ns run,A simple ns scriptset ns new,7,Wireless Features,Mobile node(ad-hoc node),Air interface,Radio propagation model,Adhoc routing protocols,Mobile IP,Wireless FeaturesMobile node(,8,Structure of a wireless node in,ns,Structure of a wireless node i,9,Sample script for a wireless simulation,#Set up hierarchical routing.,#Specify topology.,#Create God,#Create a Base Station,$ns_ node-config-adhocRouting DSR,-llType LL,-macType 802.11,-ifqType DropTail,-ifqLen 100,-antType OmniAntenna,-propType TwoRayGround,-phyType WirelessPhy,-topoInstance$topo,-wiredRouting ON,-agentTrace ON,-routerTrace ON,-macTrace ON,-movementTrace OFF,-channel$chan_,Sample script for a wireless s,10,Sample script for a wireless simulation,set BS(0)$ns_ node 1.0.0,$BS(0)random-motion 0,$BS(0)set X_ 1.0,$BS(0)set Y_ 2.0,#,create mobilenodes in the same domain as BS(0),$ns_ node-config-wiredRouting OFF,set node_(0)$ns_ node 1.0.1,$node_(0)base-station AddrParams addr2id$BS(0)node-addr,#,create and attach Agents TCP/UDP/CBR,:,:,#,include movement,.,$ns_at 10.0“$node(0)setdest 200.0 150.0 15.0,:,:,:,Sample script for a wireless s,11,Scope of the project,We simulate the network stack for the MS-BS,interaction and focus on the handling of radio,resources.,Scope of the projectWe simulat,12,GPRS Air interface,TDMA,Uplink-downlink skew of 3 slots,Physical channel=a slot on a frequency.,Logical channels Broadcast/Control/Data.,Multiplexing logical channels onto physical channels,Transmission bursts,GPRS Air interfaceTDMA,13,A radio block,(RLC PDU),0,1,2,3,4,5,6,7,0,1,2,3,4,5,6,7,0,1,2,3,200bytes,TDMA,frames,Transmission over the air interface(in GPRS),A radio block01234567012345670,14,Features of our GPRS simulator,The Set-up,A single cell,The wireless node now has LL,RLC,MAC for GPRS.,Supports traffic in either direction:MS to BS or BS to MS,BS can transmit/receive on multiple frequencies,GPRS sim,Features of our GPRS simulator,15,Air Interface/Channels,Separate uplink/downlink frequencies.,TDMA structure with 8 slots per frame.,Uplink-downlink skew of 3 slots.,User defined options:,-number of frequencies,-number of GPRS slots per frame,Signaling channel slot0,on uplink/downlink frequency 0.,GPRS sim,Air Interface/ChannelsGPRS s,16,Transmission and reception over the air-interface,RLC PDU size set to 50 bytes=,50 bytes transmitted per slot.,Propagation delay set to 0.,Timers model transmission and reception.,A radio:switched ON during transmission/reception,OFF otherwise.,GPRS sim,Transmission and reception ove,17,Signaling for Call Set-Up and Handling,Resource Request Message,from MS to BS,on the Random Access channel(slot0,freq0),lock IFQ,wait only one TDMA frame for reply,Resource Reply Message,from BS to MS on allotted channel,update vlr_ tables,wait till MS receives reply before transmitting,GPRS sim,Signaling for Call Set-Up and,18,Signaling.,Resource Release Message,from MS to BS,on the dedicated slot,clear entries,later requests will be treated on par with fresh requests,GPRS sim,Signaling.Resource Release Me,19,Resource Handling,Slot Allocation,first free slot is alloted.,allocation symmetric on uplink and downlink,.,Slot Release,MS initiates message on expiry of slot_release_timer.,BS deletes vlr_ entries on receipt of message.,timer value based on experiments.,GPRS sim,Resource HandlingSlot Allocati,20,Dealing with Exceptions,Collisions,happen only on the Random Access channel.,BS drops all colliding requests.,each MS waits one