MOBILE COMPUTING AND APPLICATION DEVELOPMENT( 3360704 ) - WordPress
UNIT-IMOBILE COMPUTING ANDAPPLICATION DEVELOPMENT(3360704)1
SYLLABUSIntroduction to Mobile Computing 1.1 Concept of Mobile Communication 1.2 Different generations of wireless technology 1.3Basics of cell, cluster and frequency reuse concept 1.4 Noise and its effects on mobile 1.5 Understanding GSM and CDMA 1.6 Basics of GSM architecture and services like voicecall, SMS, MMS, LBS, VAS 1.7 Different modes used for Mobile Communication 2
CONTINUE 1.8 Architecture of Mobile Computing(3 tier) 1.9 Design considerations for mobile computing 1.10 Characteristics of Mobile Communication1.11 Application of Mobile Communication 1.12 Security Concern Related to MobileComputing 1.13 Middleware and Gateway required formobile Computing 1.15 Making Existing Application Mobile Enable 1.16 Mobile IP 1 3
CONTINUE 1.17 Basic Mobile Computing Protocol 1.18 Mobile Communication via Satellite Low orbit satellite Medium orbit satellite Geo stationary satellite phones 4
1.1 CONCEPT OF MOBILECOMMUNICATIONCellular systems are widely used today andcellular technology needs to offer very efficientuse of the available frequency spectrum. Withbillions of mobile phones in use around the globetoday. It is necessary to re-use the available frequenciesmany times over without mutual interference ofone cell phone to another. It is this concept offrequency re-use that is at the very heart ofcellular technology. 5
CONTINUE However the infrastructure technology needed tosupport it is not simple, and it required asignificant investment to bring the first cellularnetworks on line.6
1.2 DIFFERENT GENERATIONS OFWIRELESS TECHNOLOGYWireless communicationis the transfer ofinformation or power between two or more pointsthat are not connected by an electrical conductor.The most common wireless technologies use radiowaves. With radio waves distances can be short, such asa few meters for Bluetooth or as far as millions ofkilometers for deep-space radio communications.It encompasses various types of fixed, mobile,and portable applications, including two-wayradios 7
HISTORY OF MOBILE TECHNOLOGIESTechnology1G2G2.5G3G4GDesign viceAnalog voice Digital acity,capacity,Packet data, BroadbanddataMMSAMPS, TDMA,CDMA, GPRS,WCDMA,TACS,NMT iplexingFDMACore k2010 ?Highercapacity,Complete IP,multimediaSinglestandard100 MbpsCDMACDMA ?PacketnetworkIP network(Internet)8
1.3 BASICS OF CELL, CLUSTER ANDFREQUENCY REUSE CONCEPTIntroduction to Cellular Systems Solves the problem of spectral congestion anduser capacity. Offer very high capacity in a limited spectrumwithout major technological changes. Reuse of radio channel in different cells. Enable a fix number of channels to serve anarbitrarily large number of users by reusing thechannel throughout the coverage region.9
CONTINUE Solves the problem of spectral congestion and usercapacity. Offer very high capacity in a limited spectrumwithout major technological changes. Reuse of radio channel in different cells. Enable a fix number of channels to serve anarbitrarily large number of users by reusing thechannel throughout the coverage region. 10
CONTINUE Each cellular base station is allocated a group ofradio channels within a small geographic areacalled a cell.Neighboring cells are assigned different channelgroups.By limiting the coverage area to within theboundary of the cell, the channel groups may bereused to cover different cells.Keep interference levels within tolerable limits.Frequency reuse or frequency planning11
Consider a cellular system which has a total of Sk Sduplex channels. Each cell is allocated a group of k channels,. The S channels are dividedamong N cells.S kN The total number of available radio channels The N cells which use the complete set ofchannels is called cluster. The cluster can be repeated M times within thesystem. The total number of channels, C, is usedas a measure of capacity The capacity is directly proportional to the1/ Nnumber of replication M. The cluster size, N, is typically equal to 4, 7, or 12.12
Hexagonal geometry has– exactly six equidistance neighbors– the lines joining the centers of any cell and eachof its neighbors are separated by multiples of 60degrees.2 Only certain clustercell layout areN i sizes ij andj2possible. The number of cells per cluster, N, can only havevalues which satisfy Co-channel neighbors of a particular cell, ex, i 3and j 2.13
FREQUENCY REUSE Each cellular base station is allocated a group ofradio channels within a small geographic areacalled a cell. Neighboring cells are assigned different channelgroups. By limiting the coverage area to within theboundary of the cell, the channel groups may bereused to cover different cells. Keep interference levels within tolerable limits. Frequency reuse or frequency planning14
1.4 NOISE AND ITS EFFECTS ONMOBILEThermal Noise Inter-modulation Noise Crosstalk Impulse Noise 15
THERMAL NOISEThermal noise is observed in any system havingthermal losses and is caused by thermal agitationof charge carriers. Thermal noise is also called Johnson-Nyquistnoise. (Johnson, Nyquist: 1928, Schottky: 1918). An example of thermal noise can be thermalnoise in resistors. 16
INTER-MODULATION NOISE Inter-modulation noise :Occurs if signals withdifferent frequencies share the same mediumInterference caused by a signal produced at afrequency that is the sum or difference of originalfrequencies Source.17
CROSSTALK NOISE Crosstalk is usually caused by undesiredcapacitive, inductive, or conductive coupling fromone circuit to another. In cabling, this refers tothe superimposing of either pulsed DC orstandard AC signals carried on one wire pair toanother wire pair in close proximity.18
IMPULSE NOISEImpulsive noise is most commonly associatedwith the construction and demolition industry.This sudden burst of noise can startle you by itsfast and surprising nature. Impulsive noises arecommonly created by explosions or constructionequipment such as pile drivers. To measure impulsive noise, you will needa sound level meter or a personal noisedosimeter that can calculate Peak values. 19
1.5 GSMTime Division Multiple Access Based Technology 200kHz bandwidth per carrier Deployed in reuse pattern 3/9, 4/12, 7/21 Available operating frequency 900, 1800, 1900MHz Using SIM Card 20
CDMACode Division Multiple Access Based Technology 1.25 MHz bandwidth per carrier Reuse factor 1 Available operating frequency 450, 800, 1900MHz Using RUIM Card 21
CDMAInherently superior receive sensitivity (approx. 121 dB) Tradeoff between Capacity, Coverage andQuality Soft/Softer hand-off (make before break): Precise power control algoriths minimizeinterferenceMultiple diversities:Receive Spatial Diversity trough two receiveantennas Path diversity trough rake receivers Frequency diversity trough spread spectrum Time diversity trough interleaving 22
GSMFixed coverage Receive sensitivity improvement (approx. 108dB), relies on external solutions (mastheadpre-amplifier, high power amplifier) Hard hand-off (break before make) 23
SUMMARYCDMA, compared with GSM (TDMA) technology,provide : better spectrum efficiency (more capacity) better coverage (less sites required) better voice quality better data capability better forward compatibility (same spectrum canbe reused) 24
1.6 BASICS OF GSMGSM-introduction GSM Services Architecture Security in GSM Characteristics of GSM standard Advantages of GSM Future of GSM 25
WHAT IS GSM ?GSM (Global System for Mobile communication)is a digital mobile telephony system that iswidely used in Europe and other parts of theworld. GSM uses a variation of time divisionmultiple access (TDMA) and is the most widelyused of the three digital wireless telephonytechnologies (TDMA, GSM, and CDMA). GSM digitizes and compresses data, then sends itdown a channel with two other streams of userdata, each in its own time slot. It operates ateither the 900 MHz or 1800 MHz frequency band. 26
GSM: HISTORYDeveloped by Group Spéciale Mobile (founded 1982)which was an initiative of CEPT ( Conference ofEuropean Post and Telecommunication ) Under ETSI, GSM is named as “ Global System forMobile communication “ in 1989 Full set of specifications phase-I became available in1990 Phase 2 of the GSM specifications occurs in 1995.Coverage is extended to rural areas 27
TELE SERVICESTelecommunication services that enable voicecommunication via mobile phones Offered services Mobile telephony Emergency calling 28
BEARER SERVICESInclude various data services for informationtransfer between GSM and other networks likePSTN, ISDN etc at rates from 300 to 9600 bps Short Message Service (SMS) - up to 160 character alphanumeric datatransmission to/from the mobile terminal Voice mailbox 29
SUPPLEMENTARY SERVICESCall related services : Call Waiting- Notification of an incoming call while onthe handset Call Hold- Put a caller on hold to take another call Call Barring- All calls, outgoing calls, or incoming calls Call Forwarding- Calls can be sent to various numbersdefined by the user Multi Party Call Conferencing - Link multiple callstogether 30
GSM SYSTEM ARCHITECTURE31
GSM SYSTEM ARCHITECTURE-IMobile Station (MS)Mobile Equipment (ME)Subscriber Identity Module (SIM)Base Station Subsystem (BSS)Base Transceiver Station (BTS)Base Station Controller (BSC)Network Switching Subsystem(NSS)Mobile Switching Center (MSC)Home Location Register (HLR)32
CONTINUE Visitor Location Register (VLR)Authentication Center (AUC)Equipment Identity Register (EIR)33
SYSTEM ARCHITECTUREMOBILE STATION (MS)The Mobile Station is made up of two entities:1.2.Mobile Equipment (ME)Subscriber Identity Module (SIM)34
MOBILE EQUIPMENTPortable, vehicle mounted, hand held deviceUniquely identified by an IMEI (InternationalMobile Equipment Identity)Voice and data transmissionMonitoring power and signal quality of surroundingcells for optimum handoverPower level : 0.8W – 20 W160 character long SMS.35
SIM:Smart card contains the International MobileSubscriber Identity (IMSI)Allows user to send and receive calls andreceive other subscribed servicesProtected by a password or PINCan be moved from phone to phone – containskey information to activate the phone36
SYSTEM ARCHITECTUREBASE STATION SUBSYSTEM (BSS)Base Station Subsystem is composed of two partsthat communicate across the standardized Abisinterface allowing operation between componentsmade by different suppliersBase Transceiver Station (BTS)Base Station Controller (BSC)37
BASE TRANSCEIVER STATION (BTS): Encodes, encrypts, multiplexes, modulates and feedsthe RF signals to the antenna.Communicates with Mobile station and BSCConsists of Transceivers (TRX) units38
BASE STATION CONTROLLER (BSC) Manages Radio resources for BTSAssigns Frequency and time slots for all MS’s in itsareaHandles call set upHandover for each MSIt communicates with MSC and BTS39
SYSTEM ARCHITECTURENETWORK SWITCHING SUBSYSTEM(NSS) The system contains the following functionalunits Mobile Switching Center (MSC)Home Location Register (HLR)Visitor Location Register (VLR)Authentication Center (AUC)Equipment Identity Register (EIR) 40
MOBILE SWITCHING CENTER (MSC) Heart of the networkManages communication between GSM and othernetworksBilling information and collectionMobility management- Registration- Location Updating- Inter BSS and inter MSC call handoff41
HOME LOCATION REGISTERS (HLR) Stores information about each subscriber thatbelongs to it MSC in permanent and temporaryfashion.As soon as mobile subscriber leaves its currentlocal area, the information in the HLR isupdated.database contains IMSI, MSISDN, prepaid/postpaid, roaming restrictions, supplementaryservices.42
VISITOR LOCATION REGISTERS (VLR)Temporary database which updates whenevernew MS enters its area, by HLR database Assigns a TMSI to each MS entering the VLRarea which keeps on changing. Controls those mobiles roaming in its area Database contains IMSI, MSISDN, LocationArea, authentication key 43
AUTHENTICATION CENTER (AUC)Contains the algorithms for authenticationas well as the keys for encryption. Protects network operators from fraud. Situated in special protected part of theHLR. 44
EQUIPMENT IDENTITY REGISTER (EIR)Stores all devices identifications registeredfor this network. Database that is used to track handsetsusing the IMEI (International MobileEquipment Identity) Prevents calls from stolen, unauthorised ordefective mobile devices 45
OPERATION AND MAINTENANCECENTRE (OMC) The centralized operation of the various units in thesystem and functions needed to maintain thesubsystems.Dynamic monitoring and controlling of the network.Functions :- configuration management- fault report and alarm handling- performance supervision/management- storage of system software and data46
SECURITY IN GSMOn air interface, GSM uses encryptionand TMSI instead of IMSI. SIM is provided 4-8 digit PIN tovalidate the ownership of SIM 3 algorithms are specified : - A3 algorithm for authentication - A5 algorithm for encryption - A8 algorithm for key generation 47
CHARACTERISTICS OF GSM STANDARDFully digital system using 900,1800 MHzfrequency band. User/terminal authentication for fraudcontrol. Full international roaming capability. Low speed data services (upto 9.6 Kb/s). Compatibility with ISDN. Support of Short Message Service (SMS). 48
ADVANTAGES OF GSM OVER ANALOGSYSTEMReduced RF transmission power and longerbattery life. International roaming capability. Better security against fraud (throughterminal validation and user authentication). Encryption capability for informationsecurity and privacy. 49
GSM APPLICATIONSMobile telephony GSM-R Telemetry System - Fleet management - Automatic meter reading - Toll Collection - Remote control and fault reporting ofDG sets Value Added Services 50
FUTURE OF GSM2nd Generation GSM -9.6 Kbps (data rate) 2.5 Generation ( Future of GSM) HSCSD (High Speed ckt Switched data) Data rate : 76.8 Kbps (9.6 x 8 kbps) GPRS (General Packet Radio service) Data rate: 14.4 - 115.2 Kbps EDGE (Enhanced data rate for GSMEvolution) Data rate: 547.2 Kbps (max) 51
CONTINUE 3 Generation WCDMA(Wide band CDMA) Data rate : 0.348 – 2.0 Mbps 52
1.7 DIFFERENT MODES USEDMOBILE COMMUNICATIONFORThe term wireless communication was introducedin the 19th century and wireless communicationtechnology has developed over the subsequentyears. It is one of the most important mediums oftransmission of information from one device toother devices. In this technology, the information can betransmitted through the air without requiringany cable or wires or other electronic conductors. 53
BROADCAST RADIO54
RADIOMostly an audio broadcasting service, radiobroadcasts sound through the air as radio waves.Radio uses a transmitter which is used totransmit the data in the form of radio waves to areceiving antenna(Different Types of Antennas).To broadcast common programming, stations areassociated with the radio N/W’s. The broadcasthappens either in simulcast or syndication orboth. Radio broadcasting may be done via cableFM, the net and satellites. A broadcast sendsinformation over long distances at up to twomegabits/Sec (AM/FM Radio). Radio waves are electromagnetic signals, that aretransmitted by an antenna. 55
RADIO56
MICROWAVE COMMUNICATION Microwave wireless communication is aneffective type of communication, mainly thistransmission uses radio waves, and thewavelengths of radio waves are measured incentimetres. In this communication, the data orinformation can be transfers using two methods.One is satellite method and another one isterrestrial method.57
MICROWAVE COMMUNICATION58
SATELLITE COMMUNICATION Satellite communication is one type of selfcontained wireless communication technology, it iswidely spread all over the world to allow users tostay connected almost anywhere on the earth.When the signal (a beam of modulated microwave)is sent near the satellite then, satellite amplifiesthe signal and sent it back to the antenna receiverwhich is located on the surface of the earth.Satellite communication contains two maincomponents like the space segment and the groundsegment. The ground segment consists of fixed ormobile transmission, reception and ancillaryequipment and the space segment, which mainly isthe satellite itself.59
SATELLITE COMMUNICATION60
1.8 ARCHITECTURE OF MOBILECOMPUTING(3 TIER)In mainframe computers –many system usesTP/Transaction Processing environment. At coreof TP System, there is TP Monitor Software. There is the resources like –Visual Display, Pointof Sell Terminal, Printers etc. A TP System monitors the resources at all theterminals & coordinates with the users to pick upthe right processing task to service businesstransaction. It also manages all objects &connects them by policies & rules –decided byDatabase Object/s. 61
1.9 DESIGN CONSIDERATIONSFORMOBILE COMPUTINGFirst Tier/LayerUser Interface/Presentation Layer –deals with theuser facing device handling & rendering. This tierincludes a user interfacing components likeTextbox, Labels, Checkboxes, etc.Second Tier/LayerProcess Management/application Layer –deals withBusiness logic & Rules. It is capable ofaccommodating hundreds users. 62
CONTINUE Third Tier/Layer Database Management/Data Tier –deals with DBmanagement & access. 63
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Mobile computing environment needs to be contextindependent as well as context-sensitive.Here “Context” means all information that helpdetermine the state of object. The object can beperson/device/place/physical or computationalobject/any other entity that is being tracked by thesystem.There are many ways in which contexts can beadapted, Content with Context Awareness Content switch on Context Content Transcoding on Context65
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WAP -ARCHITECTUREWAP Architecture It provides a scalable and extensible environmentfor application development of mobile This is achieved using layered design of protocolstack. The layers resemble the layers of OSImodel. Each layer is accessible by layers above as well asby other services and applications through a setof well defined interface. External applications may access session,transaction, security and transport layersdirectly. 68
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WAP –PROTOCOL LAYERSArchitecture of the WAP Protocol Stack. TheWAP protocol stack has a multi-layeredarchitecture (this is very similar to the sevenlayers model of OSI. The Wireless Application Environment (WAE)defines the following functions: Wireless MarkupLanguage (WML). 72
1.10 CHARACTERISTICS OF MOBILECOMMUNICATIONCommunication Total mobility Worlds wide connectivity High capacity High transmission quality Security function 73
1.12 SECURITY CONCERN RELATEDTO MOBILE COMPUTINGLow bandwidth minimize message sizes, number of messages Increased risk of eavesdropping use link-level encryption ("wired equivalency") Also wireless networks typically implyuser/device mobility Security issues related to mobility authentication charging privacy Focus of this presentation 74
GSM/GPRS SECURITY Authentication Charging one-way authentication based on long-term shared keybetween user's SIM card and the home networknetwork operator is trusted to charge correctly; based onuser authenticationPrivacy data link-level encryption over the air; no protection in the corenetworkidentity/location/movements, unlinkability use of temporary identifiers (TMSI) reduce the ability of aneavedropper to track movements within a PLMNbut network can ask the mobile to send its real identity (IMSI):on synchronization failure, on database failure, or on entering anew PLMNnetwork can also page for mobiles using IMSI75
3GPP/UMTS ENHANCEMENTS(CURRENT STATUS) Authentication Charging support for mutual authenticationsame as in GSMPrivacy data identity/location/movements, unlinkability some support for securing core network signaling dataincreased key sizesenhanced user identity confidentiality using "group keys"a group key is shared by a group of usersOther improvements integrity of signaling, cryptographic algorithms madepublic76
WHAT IS DIFFERENT IN THEWIRELESS INTERNET?Potentially low cost of entry for ISPs supportingmobile access Consequently, old trust assumptions as incellular networks may not hold here Implications: potential need for between user and home ISPbetween user and visited ISPbetween ISPsincontestable chargingincreased level of privacyRelevant even in cellular networks?77
ENHANCED PRIVACY Stronger levels or privacy temporary id home-domain, E(K, random bits real-id )using public key encryption K is the public encryption key of the home-domainusing opaque tokensK is a symmetric encryption key known only to the homedomain tokens are opaque to the mobile user user requires means of obtaining new tokens no danger of loss of synchronization78
ENHANCED PRIVACY (CONTD.) Release information on a need-to-know basis:e.g., does the visited domain need to know thereal identity? typically, the visited domain cares about being paidground rule: stress authorization not authenticationrequire authentication only where necessary (e.g.,home agent forwarding service in Mobile IP)79
IMPLICATIONS Public-key cryptography can provide effectivesolutions increased message sizes: use of elliptic curvecryptography can help lack of PKI: enhanced privacy solution doesnot require a full-fledged PKI, some sort ofinfrastructure is required for charging anyway80
SUMMARYTrust assumptions are different in the Internet Enhanced levels of security services may benecessary Public-key cryptography can provide effectivesolutions Try not to preclude future provision of improvedsecurity services 81
1.13 MIDDLEWARE AND GATEWAYREQUIRED FOR MOBILE COMPUTINGThere are some middleware components likebehavior management middleware, which can bea layer between the client device and theapplication. In mobile computing context we need differenttypes of middleware components and gateways atdifferent layers of the architecture (Figure 1). These are:1. Communication middleware2. Transaction processing middleware3. Behavior management middleware4. Communication gateways. 82
A SCHEMATIC REPRESENTATION OF A MOBILECOMPUTING ENVIRONMENT
COMMUNICATION MIDDLEWAREThe application will communicate with differentnodes and services through differentcommunication middleware. Different connectors for different services willfall in this category. Examples could be TN3270 for IBM mainframeservices, or Javamail connector for IMAP orPOP3 services 84
TRANSACTION PROCESSINGMIDDLEWAREIn many cases a service will offer session orienteddialogue (SoD). For a session we need to maintain a state overthe stateless Internet. This is done through an application server. The user may be using a device, which demandsa short transaction whereas the service at thebackend offers a SoD. In such cases a separate middleware componentwill be required to convert a SoD to a shorttransaction. 85
BEHAVIOR MANAGEMENTMIDDLEWAREFor different devices we need different types ofrendering. We can have applications, which are developedspecially for different types of rendering. For example, we can have one application forWeb, another for WAP, and a different one forSMS. 86
COMMUNICATION GATEWAYSBetween the device and the middleware therewill be network of networks. Gateways are deployed when there are differenttransport bearers or networks with dissimilarprotocols. For example, we need an IVR (Interactive VoiceResponse) gateway to interface voice with acomputer, or an WAP gateway to access internetover a mobile phone. 87
1.15 MAKING EXISTING APPLICATIONMOBILE ENABLE Most non-trivial web applications were builtaround the notion of Model-View-Controller(MVC), where the controller resided on theserver. The server maintained session state and,through forwards or redirects, navigated the userrequest to the next page to be rendered. Eachclient request typically resulted in mark up forthe entire page, even if only parts of that pagechanged from view to view. Port let frameworkswere introduced to solve this problem and enablemore flexibility with page aggregation.88
1.16 MOBILE IPMobile IP (or MIP) is an Internet EngineeringTask Force (IETF) standard communicationsprotocol that is designed to allow mobile deviceusers to move from one network to another whilemaintaining a permanent IP address. Mobile IP for IPv4 is described in IETF RFC5944, and extensions are defined in IETF RFC4721. 89
1.17 BASIC MOBILE COMPUTINGPROTOCOL1. Mobile Node.A host or router that changes its point ofattachment from one network or sub network toanother. A mobile node may change its locationwithout changing its IP address.It may continue to communicate with otherInternet nodes at any location using its (constant)IP address, assuming link layer connectivity to apoint of attachment is available. 90
CONTINUE 2. Home AgentA router on a mobile node’s home network thattunnels datagrams for delivery to the mobilenode when it is away from home, and maintainscurrent location information for the mobilenode. 91
CONTINUE 3. Foreign AgentA router on a mobile node’s visited network thatprovides routing services to the mobile node whileregistered. The foreign agent detunes and deliversdatagrams to the mobile node that were tunnelledby the mobile node’s home agent.For datagrams sent by a mobile node, the foreignagent may serve as a default router for registeredmobile nodes. A mobile node is given a long-term IPaddress on a home network. This home address isadministered in the same way that a “permanent”IP address is provided to a stationary host. 92
1.18 MOBILE COMMUNICATION VIASATELLITEA satellite is an object that revolves aroundanother object. For example, earth is a satellite ofThe Sun, and moon is a satellite of earth. A communication satellite is a microwaverepeater station in a space that is used fortelecommunication, radio and television signals.A communication satellite processes the datacoming from one earth station and it converts thedata into another form and send it to the secondearth station. 93
APPLICATIONS Traditionallyweather satellites radio and TV broadcast satellites military satellites satellites for navigation and localization (e.g., GPS) Telecommunicationglobal telephone connections backbone for global networks connections for communication in remote places orunderdeveloped areas global mobile communication satellite systems to extend cellular phone systems(e.g., GSM or AMPS)94
CLASSICAL SATELLITE SYSTEMSInter Satellite Link(ISL)Mobile UserLink (MUL)Gateway Link(GWL)MULGWLsmall cells(spotbeams)base stationor gatewayfootprintISDNPSTN: Public SwitchedTelephone NetworkPSTNGSMUser data95
BASICS Satellites in circular orbitsattractive force Fg m g (R/r)² centrifugal force Fc m r ² m: mass of the satellite R: radius of the earth (R 6370 km) r: distance to the center of the earth g: acceleration of gravity (g 9.81 m/s²)2 frequency) : angular velocity ( 2 f, f: rotation Stable orbit Fg F cr 3gR2(2 f )96
SATELLITE PERIOD AND ORBITS24satelliteperiod [h]velocity [ x1000 km/h]20161284synchronous distance35,786 km102030radius40 x106 m97
BASICSelliptical or circular orbits complete rotation time depends on distance satelliteearth inclination: angle between orbit and equator elevation: angle between satellite and horizon LOS (Line of Sight) to the satellite necessary forconnection high elevation needed, less absorption due to e.g.buildings Uplink: connection base station - satellite Downlink: connection satellite - base station typically separated frequencies for uplink anddownlink 98
INCLINATIONplane of satellite orbitsatellite orbitperigeedinclination dequatorial plane99
ELEVATIONElevation:angle e between center of satellite beamand surfaceminimal elevation:elevation needed at leasteto communicate with the satellite100
LINK BUDGET OF SATELLITESParameters like attenuation or received powerdetermined by four parameters: sending power2 4 r f gain of sending antennaL c distance between senderand receiver gain of receiving antenna Problems varying strength of received signal due tomultipath propagation interruptions due to shadowing of signal (noLOS) 101
Attenuation ofthe signal in %ATMOSPHERIC ATTENUATIONExample: satellite systems at 4-6 GHz5040rain absorption30fog absorptione2010atmosphericabsorption5 10 20 30 elevation of the satellite40 50 102
ORBITS IFour different types of satellite orbits can beidentified depending on the shape and diameter ofthe orbit: GEO: geostationary orbit, ca. 36000 km aboveearth surface LEO (Low Earth Orbit): ca. 500 - 1500 km MEO (Medium Earth Orbit) or ICO (IntermediateCircular Orbit): ca. 6000 - 20000 km HEO (Highly Elliptical Orbit) elliptical orbits 103
ORBITS IIGEO (Inmarsat)HEOMEO (ICO)LEO(Globalstar,Irdium)inner and outer VanAllen beltsearth100010000Van-Allen-Belts:ionized particles2000 - 6000 km and15000 - 30000 kmabove earth surface35768km104
GEOSTATIONARYSATELLITESOrbit 35,786 km distance to earth surface, orbitin equatorial plane (inclination 0 ) complete rotation exactly one day, satellite issynchronous to earth rotation fix antenna positions, no adjusting necessary satellites typically have a large footprint (up to34% of earth surface!), therefore difficult to reusefreq
SYLLABUS Introduction to Mobile Computing 1.1 Concept of Mobile Communication 1.2 Different generations of wireless technology 1.3 Basics of cell, cluster and frequency reuse concept 1.4 Noise and its effects on mobile 1.5 Understanding GSM and CDMA 1.6 Basics of GSM architecture and services like voice call, SMS, MMS, LBS, VAS 1.7 Different modes used for Mobile Communication
Cloud Computing J.B.I.E.T Page 5 Computing Paradigm Distinctions . The high-technology community has argued for many years about the precise definitions of centralized computing, parallel computing, distributed computing, and cloud computing. In general, distributed computing is the opposite of centralized computing.
Mobile Cloud Computing Cloud Computing has been identified as the next generation’s computing infrastructure. Cloud Computing allows access to infrastructure, platforms, and software provided by cloud providers at low cost, in an on-demand fashion. Mobile Cloud Computing is introduced as an int
distributed. Some authors consider cloud computing to be a form of utility computing or service computing. Ubiquitous computing refers to computing with pervasive devices at any place and time using wired or wireless communication. Internet computing is even broader and covers all computing paradigms over the Internet.
Chapter 10 Cloud Computing: A Paradigm Shift 118 119 The Business Values of Cloud Computing Cost savings was the initial selling point of cloud computing. Cloud computing changes the way organisations think about IT costs. Advocates of cloud computing suggest that cloud computing will result in cost savings through
cloud computing, mobile cloud, fog computing, heteroge-neous resource sharing, service-oriented 1. INTRODUCTION Recent advances of cloud computing platforms and mobile devices have given rise to mobile cloud computing (MCC), which is a new paradigm for mobile applications and services that promises to have a strong impact on our lifestyle. Ini-
CMU in Silicon Valley Established 2002 Significant growth in the past 10 years Mobile computing as a disruptive force First wave of mobile computing: . consist of developer's code some cloud service IP packets traveling mobile-to-cloud or mobile-to-mobile
Strategy 6: Mobile Workload Mobile devices are increasingly driving mainframe workloads April 2014: Mobile Workload Pricing – 60% reduction in mobile workload CPU to R4HA peak MUST be from mobile device MUST show connection to mobile device – Mobile Safari good – Desktop Safari not good Mobile to mainframe is .
1/25/21 2 Course Goals Fundamentals of mobile computing Fundamentals of wireless networking Topics from closely related areas: Pervasive Computing Wearables Internet of Things Real-Time Systems Embedded Systems Wireless sensor networks Acquire and practice development skills Mini projects and course/group project Mobile Computing &
