This document provides an introduction to mobile computing. It defines mobile computing as using a computer while on the move, involving mobility, computing, and network connectivity. The key aspects of mobile computing are discussed, including mobile communication infrastructure, software, hardware, and devices. Common network types that enable mobile computing like WLAN, MAN, WAN, and wireless networks are also summarized. The relationship between mobile computing and wireless networking is described, with wireless networking providing the basic communication capabilities. Examples of mobile computing applications are given for various fields.
Mobile computing allows users to access network services and computational resources from anywhere using portable devices like laptops, smartphones, and tablets. It is defined as computing using portable devices that maintain network connectivity while on the move. Mobile computing faces challenges like low bandwidth, disconnection, and security risks compared to wired networks. Future advancements may include increased use of artificial intelligence and integrated circuits to develop more compact devices with faster processors. Mobile computing has transitioned through generations from 1G analog cellular to 2G digital cellular to 3G broadband cellular and beyond to 4G and 5G.
These slides cover a topic on Virtual circuit & message switching in Data Communication. All the slides are explained in a very simple manner. It is useful for engineering students & also for the candidates who want to master data communication & computer networking
In the seven-layer OSI model of computer networking, media access control (MAC) data communication protocol is a sublayer of the data link layer (layer 2). The MAC sublayer provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multiple access network that incorporates a shared medium, e.g. an Ethernet network. The hardware that implements the MAC is referred to as a media access controller.
The MAC sublayer acts as an interface between the logical link control (LLC) sublayer and the network's physical layer. The MAC layer emulates a full-duplex logical communication channel in a multi-point network. This channel may provide unicast, multicast or broadcast communication service.
The document discusses internetworking models and the OSI reference model. It provides details on each of the 7 layers of the OSI model:
1. The Application layer handles communication between applications and users.
2. The Presentation layer translates and formats data for transmission.
3. The Session layer establishes and manages communication sessions between devices.
4. The Transport layer segments data, establishes logical connections, and ensures reliable delivery between hosts.
Cellular communication systems have evolved through multiple generations from analog 1G to digital 4G systems. A cellular network is divided into geographical areas called cells served by base transceiver stations. Cells are grouped into clusters where frequencies are reused to allow for more subscribers. When making a call, the cellular phone registers with the local base station which routes the call through switching centers to establish communication with the intended recipient. Modern cellular networks support additional services beyond voice like texting, internet access, and location tracking through technologies like GSM that employ protocols like TDMA for efficient frequency usage.
This document provides an overview of mobile communication and wireless networks. It discusses applications such as use in vehicles, emergencies, and business. It also covers a brief history of wireless communication and open research topics like interference and security issues. A simplified reference model is presented showing the protocol stack from the physical to application layers in a wireless environment.
Short Message Service (SMS) allows mobile devices to exchange short text messages and was first used in 1992; it works by sending text messages through a Short Message Service Center (SMSC) which delivers the message to the intended recipient's mobile device using cellular network protocols. SMS is widely used for communication, advertising, and value added services but many have switched to messaging apps for lower costs as SMS usage in India has declined significantly since 2013 with the rise of internet-based messaging platforms.
Mobile computing allows users to access network services and computational resources from anywhere using portable devices like laptops, smartphones, and tablets. It is defined as computing using portable devices that maintain network connectivity while on the move. Mobile computing faces challenges like low bandwidth, disconnection, and security risks compared to wired networks. Future advancements may include increased use of artificial intelligence and integrated circuits to develop more compact devices with faster processors. Mobile computing has transitioned through generations from 1G analog cellular to 2G digital cellular to 3G broadband cellular and beyond to 4G and 5G.
These slides cover a topic on Virtual circuit & message switching in Data Communication. All the slides are explained in a very simple manner. It is useful for engineering students & also for the candidates who want to master data communication & computer networking
In the seven-layer OSI model of computer networking, media access control (MAC) data communication protocol is a sublayer of the data link layer (layer 2). The MAC sublayer provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multiple access network that incorporates a shared medium, e.g. an Ethernet network. The hardware that implements the MAC is referred to as a media access controller.
The MAC sublayer acts as an interface between the logical link control (LLC) sublayer and the network's physical layer. The MAC layer emulates a full-duplex logical communication channel in a multi-point network. This channel may provide unicast, multicast or broadcast communication service.
The document discusses internetworking models and the OSI reference model. It provides details on each of the 7 layers of the OSI model:
1. The Application layer handles communication between applications and users.
2. The Presentation layer translates and formats data for transmission.
3. The Session layer establishes and manages communication sessions between devices.
4. The Transport layer segments data, establishes logical connections, and ensures reliable delivery between hosts.
Cellular communication systems have evolved through multiple generations from analog 1G to digital 4G systems. A cellular network is divided into geographical areas called cells served by base transceiver stations. Cells are grouped into clusters where frequencies are reused to allow for more subscribers. When making a call, the cellular phone registers with the local base station which routes the call through switching centers to establish communication with the intended recipient. Modern cellular networks support additional services beyond voice like texting, internet access, and location tracking through technologies like GSM that employ protocols like TDMA for efficient frequency usage.
This document provides an overview of mobile communication and wireless networks. It discusses applications such as use in vehicles, emergencies, and business. It also covers a brief history of wireless communication and open research topics like interference and security issues. A simplified reference model is presented showing the protocol stack from the physical to application layers in a wireless environment.
Short Message Service (SMS) allows mobile devices to exchange short text messages and was first used in 1992; it works by sending text messages through a Short Message Service Center (SMSC) which delivers the message to the intended recipient's mobile device using cellular network protocols. SMS is widely used for communication, advertising, and value added services but many have switched to messaging apps for lower costs as SMS usage in India has declined significantly since 2013 with the rise of internet-based messaging platforms.
This document provides an overview of cellular networks. It discusses key concepts like cells, base stations, frequency reuse, and multiple access methods. It describes how location of mobile devices is managed through location updating and paging. It also covers handoff which allows active calls to continue seamlessly as users move between different cells.
The document discusses the network layer in computer networking. It describes how the network layer is responsible for routing packets from their source to destination. It covers different routing algorithms like distance vector routing and link state routing. It also compares connectionless and connection-oriented services, as well as datagram and virtual circuit subnets. Key aspects of routing algorithms like optimality, stability, and fairness are defined.
A handover is the process of transferring a cellular call or data session from one cell site to another without disconnecting as the user moves between different cells. There are different types of handovers including intra-cell handovers which change channels within the same cell, inter-cell handovers which transfer between different cells, hard handovers which instantly terminate the existing connection to establish a new one, and soft handovers which connect to the new channel before disconnecting the existing connection to provide a smoother transition.
Introduction: Mobile Communications, Mobile Computing – Paradigm, Promises/Novel Applications and Impediments and Architecture; Mobile and Handheld Devices, Limitations of Mobile and Handheld Devices.
GSM – Services, System Architecture, Radio Interfaces, Protocols, Localization, Calling, Handover, Security, New Data Services, GPRS, CSHSD, DECT.
The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology.
UNIT I INTRODUCTION
Introduction to Mobile Computing – Applications of Mobile Computing- Generations of Mobile Communication Technologies- Multiplexing – Spread spectrum -MAC Protocols – SDMA- TDMA- FDMA- CDMA
Replication in computing involves sharing information so as to ensure consistency between redundant resources, such as software or hardware components, to improve reliability, fault-tolerance, or accessibility.
IT8602 Mobile Communication - Unit I Introductionpkaviya
This document provides an introduction and overview of mobile computing and related technologies. It begins with definitions of mobile computing and discusses characteristics like ubiquity, location awareness, and adaptation. It then covers applications of mobile computing like in vehicles, emergencies, and business. The document discusses generations of mobile communication technologies and different multiple access protocols like SDMA, TDMA, FDMA, and CDMA. It provides details on TDMA protocols including fixed TDM, Aloha, slotted Aloha, and CSMA.
This document discusses different types of computer network switching, including circuit switching, packet switching, and virtual circuit switching. Circuit switching establishes a dedicated connection between nodes for the duration of a call. Packet switching divides messages into packets that are routed independently through a network on a first-come, first-served basis without dedicated connections. Virtual circuit switching combines aspects of circuit switching and packet switching by establishing paths for packets through a three-phase process of setup, data transfer using local addressing, and teardown.
The document summarizes several wireless network standards and technologies:
- AMPS was the first analog cellular standard developed in 1983 using FDMA. It used half of the signal for sending and half for receiving.
- IS-95 and IS-136 were 2G digital standards, with IS-95 using CDMA and IS-136 using TDMA. GSM is a widely used global 2G standard using TDMA.
- GPRS, EDGE, WCDMA, and CDMA2000 were 3G standards providing faster data speeds and packet-switched networks, with WCDMA and CDMA2000 being the main 3G technologies.
This document discusses multiplexing techniques used in mobile computing. It describes four types of multiplexing: frequency division multiplexing (FDM), time division multiplexing (TDM), code division multiplexing (CDM), and space division multiplexing (SDM). For each type, it provides details on how the technique works and its advantages and disadvantages. FDM uses different frequencies to transmit multiple signals simultaneously. TDM divides a signal into time slots to share a frequency. CDM assigns unique codes to signals sharing the same frequency. SDM splits a channel across physical locations.
GPRS Architecture and its components are covered extensively.
The slides give a little information about gprs and also gets into deeper explanation of its architecture.
This document provides an introduction to mobile computing. It discusses how information is the foundation of decision making and differentiates humans from animals. It explores the evolution of computing from centralized mainframes to ubiquitous computing accessible anywhere, anytime from any device. The document examines the attributes of mobility and how physical mobility evolved into logical mobility. It outlines some motivations and functions of mobile computing as well as examples of mobile applications.
This document provides an overview of cellular networks. It begins with an introduction that defines a cellular network as a radio network composed of radio cells served by base stations. It then discusses how cellular networks work by allowing mobile devices to connect to the nearest base station and hand off connections between stations as the device moves between cells. Finally, it covers benefits like increased network capacity and coverage area as well as examples of cellular technologies used in modern mobile phone networks.
This document discusses mobility management (MM) in GPRS and UMTS networks. It describes the different MM states in GPRS (IDLE, STANDBY, READY) and UMTS (PMM-DETACHED, PMM-IDLE, PMM-CONNECTED). The MM contexts maintained by the MS, SGSN, and HLR/AUC are also outlined. Periodic and normal location update procedures performed by the MS to update its location are explained.
System Interconnect Architectures,Network Properties and Routing,Linear Array,
Ring and Chordal Ring,
Barrel Shifter,
Tree and Star,
Fat Tree,
Mesh and Torus,Dynamic InterConnection Networks,Dynamic bus ,Switch Modules
,Multistage Networks,Omega Network,Baseline Network,Crossbar Networks
The document discusses desirable features of mobile IP, including transparency, compatibility, security, and efficiency & scalability. Transparency refers to mobile IP being invisible to higher level protocols and applications. Compatibility means mobile IP should be compatible with existing Internet protocols and support all web browsers. Security involves authenticating mobile IP and protecting against attackers with fake IP addresses. Efficiency & scalability requires mobile IP to not flood the network or compromise efficiency as it supports billions of moving hosts and various devices.
The network layer provides two main services: connectionless and connection-oriented. Connectionless service routes packets independently through routers using destination addresses and routing tables. Connection-oriented service establishes a virtual circuit between source and destination, routing all related traffic along the pre-determined path. The document also discusses store-and-forward packet switching, where packets are stored until fully received before being forwarded, and services provided to the transport layer like uniform addressing.
This document provides an overview of data communication systems and computer networks. It discusses the key components of a data communication system including the message, sender, receiver, transmission medium, and protocols. It then describes different data transmission modes such as simplex, half-duplex, and full-duplex. The document also covers computer network types including LANs, MANs, and WANs, as well as network topologies like mesh, star, bus, and ring configurations. Finally, it discusses some common uses of computer networks for businesses and homes.
Mobile computing allows users to access computer networks and services while on the move. It enables connectivity anywhere and anytime using portable devices like laptops, smartphones and tablets that have wireless network connections. Mobile computing builds on wireless networking infrastructure to provide network access and remote computational services to users regardless of location. It involves various technologies and standards like GSM that support user and network mobility through wireless cellular networks.
IT6601 MOBILE COMPUTING UNITI
INTRODUCTION
Mobile Computing – Mobile Computing Vs wireless Networking – Mobile Computing Applications – Characteristics of Mobile computing – Structure of Mobile Computing Application. MAC Protocols – Wireless MAC Issues – Fixed Assignment Schemes – Random Assignment Schemes – Reservation Based Schemes.
This document contains 26 questions and answers related to mobile computing. It covers topics such as the definition of mobile computing, types of mobility, applications of mobile computing, obstacles in mobile communications, wireless local area networks, mobile middleware, logical channels in GSM networks, and the definition of wireless telecommunications. The document provides detailed explanations and examples for each question.
This document provides an overview of cellular networks. It discusses key concepts like cells, base stations, frequency reuse, and multiple access methods. It describes how location of mobile devices is managed through location updating and paging. It also covers handoff which allows active calls to continue seamlessly as users move between different cells.
The document discusses the network layer in computer networking. It describes how the network layer is responsible for routing packets from their source to destination. It covers different routing algorithms like distance vector routing and link state routing. It also compares connectionless and connection-oriented services, as well as datagram and virtual circuit subnets. Key aspects of routing algorithms like optimality, stability, and fairness are defined.
A handover is the process of transferring a cellular call or data session from one cell site to another without disconnecting as the user moves between different cells. There are different types of handovers including intra-cell handovers which change channels within the same cell, inter-cell handovers which transfer between different cells, hard handovers which instantly terminate the existing connection to establish a new one, and soft handovers which connect to the new channel before disconnecting the existing connection to provide a smoother transition.
Introduction: Mobile Communications, Mobile Computing – Paradigm, Promises/Novel Applications and Impediments and Architecture; Mobile and Handheld Devices, Limitations of Mobile and Handheld Devices.
GSM – Services, System Architecture, Radio Interfaces, Protocols, Localization, Calling, Handover, Security, New Data Services, GPRS, CSHSD, DECT.
The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology.
UNIT I INTRODUCTION
Introduction to Mobile Computing – Applications of Mobile Computing- Generations of Mobile Communication Technologies- Multiplexing – Spread spectrum -MAC Protocols – SDMA- TDMA- FDMA- CDMA
Replication in computing involves sharing information so as to ensure consistency between redundant resources, such as software or hardware components, to improve reliability, fault-tolerance, or accessibility.
IT8602 Mobile Communication - Unit I Introductionpkaviya
This document provides an introduction and overview of mobile computing and related technologies. It begins with definitions of mobile computing and discusses characteristics like ubiquity, location awareness, and adaptation. It then covers applications of mobile computing like in vehicles, emergencies, and business. The document discusses generations of mobile communication technologies and different multiple access protocols like SDMA, TDMA, FDMA, and CDMA. It provides details on TDMA protocols including fixed TDM, Aloha, slotted Aloha, and CSMA.
This document discusses different types of computer network switching, including circuit switching, packet switching, and virtual circuit switching. Circuit switching establishes a dedicated connection between nodes for the duration of a call. Packet switching divides messages into packets that are routed independently through a network on a first-come, first-served basis without dedicated connections. Virtual circuit switching combines aspects of circuit switching and packet switching by establishing paths for packets through a three-phase process of setup, data transfer using local addressing, and teardown.
The document summarizes several wireless network standards and technologies:
- AMPS was the first analog cellular standard developed in 1983 using FDMA. It used half of the signal for sending and half for receiving.
- IS-95 and IS-136 were 2G digital standards, with IS-95 using CDMA and IS-136 using TDMA. GSM is a widely used global 2G standard using TDMA.
- GPRS, EDGE, WCDMA, and CDMA2000 were 3G standards providing faster data speeds and packet-switched networks, with WCDMA and CDMA2000 being the main 3G technologies.
This document discusses multiplexing techniques used in mobile computing. It describes four types of multiplexing: frequency division multiplexing (FDM), time division multiplexing (TDM), code division multiplexing (CDM), and space division multiplexing (SDM). For each type, it provides details on how the technique works and its advantages and disadvantages. FDM uses different frequencies to transmit multiple signals simultaneously. TDM divides a signal into time slots to share a frequency. CDM assigns unique codes to signals sharing the same frequency. SDM splits a channel across physical locations.
GPRS Architecture and its components are covered extensively.
The slides give a little information about gprs and also gets into deeper explanation of its architecture.
This document provides an introduction to mobile computing. It discusses how information is the foundation of decision making and differentiates humans from animals. It explores the evolution of computing from centralized mainframes to ubiquitous computing accessible anywhere, anytime from any device. The document examines the attributes of mobility and how physical mobility evolved into logical mobility. It outlines some motivations and functions of mobile computing as well as examples of mobile applications.
This document provides an overview of cellular networks. It begins with an introduction that defines a cellular network as a radio network composed of radio cells served by base stations. It then discusses how cellular networks work by allowing mobile devices to connect to the nearest base station and hand off connections between stations as the device moves between cells. Finally, it covers benefits like increased network capacity and coverage area as well as examples of cellular technologies used in modern mobile phone networks.
This document discusses mobility management (MM) in GPRS and UMTS networks. It describes the different MM states in GPRS (IDLE, STANDBY, READY) and UMTS (PMM-DETACHED, PMM-IDLE, PMM-CONNECTED). The MM contexts maintained by the MS, SGSN, and HLR/AUC are also outlined. Periodic and normal location update procedures performed by the MS to update its location are explained.
System Interconnect Architectures,Network Properties and Routing,Linear Array,
Ring and Chordal Ring,
Barrel Shifter,
Tree and Star,
Fat Tree,
Mesh and Torus,Dynamic InterConnection Networks,Dynamic bus ,Switch Modules
,Multistage Networks,Omega Network,Baseline Network,Crossbar Networks
The document discusses desirable features of mobile IP, including transparency, compatibility, security, and efficiency & scalability. Transparency refers to mobile IP being invisible to higher level protocols and applications. Compatibility means mobile IP should be compatible with existing Internet protocols and support all web browsers. Security involves authenticating mobile IP and protecting against attackers with fake IP addresses. Efficiency & scalability requires mobile IP to not flood the network or compromise efficiency as it supports billions of moving hosts and various devices.
The network layer provides two main services: connectionless and connection-oriented. Connectionless service routes packets independently through routers using destination addresses and routing tables. Connection-oriented service establishes a virtual circuit between source and destination, routing all related traffic along the pre-determined path. The document also discusses store-and-forward packet switching, where packets are stored until fully received before being forwarded, and services provided to the transport layer like uniform addressing.
This document provides an overview of data communication systems and computer networks. It discusses the key components of a data communication system including the message, sender, receiver, transmission medium, and protocols. It then describes different data transmission modes such as simplex, half-duplex, and full-duplex. The document also covers computer network types including LANs, MANs, and WANs, as well as network topologies like mesh, star, bus, and ring configurations. Finally, it discusses some common uses of computer networks for businesses and homes.
Mobile computing allows users to access computer networks and services while on the move. It enables connectivity anywhere and anytime using portable devices like laptops, smartphones and tablets that have wireless network connections. Mobile computing builds on wireless networking infrastructure to provide network access and remote computational services to users regardless of location. It involves various technologies and standards like GSM that support user and network mobility through wireless cellular networks.
IT6601 MOBILE COMPUTING UNITI
INTRODUCTION
Mobile Computing – Mobile Computing Vs wireless Networking – Mobile Computing Applications – Characteristics of Mobile computing – Structure of Mobile Computing Application. MAC Protocols – Wireless MAC Issues – Fixed Assignment Schemes – Random Assignment Schemes – Reservation Based Schemes.
This document contains 26 questions and answers related to mobile computing. It covers topics such as the definition of mobile computing, types of mobility, applications of mobile computing, obstacles in mobile communications, wireless local area networks, mobile middleware, logical channels in GSM networks, and the definition of wireless telecommunications. The document provides detailed explanations and examples for each question.
This document provides information about the syllabus for a mobile computing course. It discusses key concepts like mobile computing definitions, types of mobility, advantages and disadvantages of mobile computing, differences between wired and mobile networks, mobile computing devices, and wireless transmission problems. It also covers MAC protocols, classifications of wireless networks, applications of mobile computing, and characteristics of mobile computing applications. The document contains questions and answers on these mobile computing topics.
The document provides information about the syllabus for a mobile computing course. It includes:
- Definitions of mobile computing and related terms like mobility and computing.
- Characteristics of mobile computing like ubiquity, location awareness, and personalization.
- Differences between mobile computing, wireless networking, and issues faced in wireless transmission.
- MAC protocols for wireless networks including CSMA/CA and RTS/CTS schemes.
The document discusses the syllabus for a Mobile Computing course. It covers topics like introduction to mobile computing, mobile internet protocols, transport layer protocols, and MAC protocols. Key concepts explained include mobile IP, care-of addresses, tunneling, TCP, DHCP, classifications of MAC protocols like CSMA/CA and RTS/CTS. Questions at the end evaluate student understanding of these mobile computing fundamentals.
This document discusses integrating the internet with mobile ad-hoc networks using an extended version of the AODV routing protocol. It begins with an introduction to mobile ad-hoc networks and their applications. It then discusses challenges in routing for MANETs and existing routing protocols like AODV. It proposes extending the AODV protocol with additional "I-flag" to discover internet gateways. The extended RREQ and RREP messages are described. It then discusses using the Network Simulator 2 to simulate this extended AODV approach with different scenarios connecting wireless and wired networks via 1 or more hops. The goal is to provide internet connectivity for mobile nodes with high packet delivery and low delay.
This document provides an overview of computer networks and wireless networks. It discusses the different types of network topologies including bus, star, ring, tree, and mesh. It also describes different network models like PAN, LAN, MAN, and WAN according to the geographical area covered. The document introduces various internetworking tools such as bridges, routers, and gateways. It provides a brief history of the OSI model and describes the seven layers of the OSI model. Finally, it discusses wireless networks and different wireless technologies including 2G, 3G, WLAN, and WiMAX.
Mobile computing allows users to access network services from anywhere using portable devices. It involves user mobility between locations and networks, as well as device portability. Mobile computing is based on wireless networking technologies and includes challenges such as disconnection, variable bandwidth, and security risks. Future advances may include increased use of artificial intelligence, integrated circuitry for compact sizes, and faster processors. Media access control (MAC) protocols are important for managing shared wireless channels and avoiding collisions between devices. Common MAC protocols include TDMA, FDMA, CDMA, ALOHA, slotted ALOHA, CSMA, and reservation-based schemes like RTS/CTS.
Implementation of Vertical Handoff Algorithm between IEEE 802.11 WLAN & CDMA ...IOSR Journals
Abstract : Wireless communications is the fastest growing segment of the communications industry. Everyone wants the quality of services anytime & anywhere. Wireless networks can integrate various heterogeneous radio access technologies as GSM, WLAN, Wimax etc. WiMAX is an IP based, wireless broadband access technology that provides performance similar to 802.11/Wi-Fi networks with the coverage and QOS (quality of service) of cellular networks. WiMAX is also an acronym meaning "Worldwide Interoperability for Microwave Access (WiMAX). The main promise of interconnecting these heterogeneous networks is to provide high performance in achieving a high data rate and support real time applications. These services require various networks (such as CDMA2000 and Wireless LAN) to be integrated into IP-based networks, which further require a seamless vertical handoff to 4th generation wireless networks. When a mobile host (MH) changes its point of attachment, its IP address gets changed. MH should be able to maintain all the existing connections using the new IP address. This process of changing a connection from one IP address to another one in IP network is called handoff. Vertical handoff is switching from one network to another while maintaining the session. Vertical Handoff (VHO) is a major concern for different heterogeneous networks. VHO can be user requested or based on some criteria already designed by the researcher of that particular algorithm. The main objective is to implement efficient & effective handoff scheme between two heterogeneous network ie. 802.11 WLAN & CDMA. Keywords - CDMA , 4G, Vertical Handoff, WLAN
Implementation of Vertical Handoff Algorithm between IEEE 802.11 WLAN & CDMA ...IOSR Journals
Wireless communications is the fastest growing segment of the communications industry. Everyone
wants the quality of services anytime & anywhere. Wireless networks can integrate various heterogeneous radio
access technologies as GSM, WLAN, Wimax etc. WiMAX is an IP based, wireless broadband access technology
that provides performance similar to 802.11/Wi-Fi networks with the coverage and QOS (quality of service) of
cellular networks. WiMAX is also an acronym meaning "Worldwide Interoperability for Microwave Access
(WiMAX). The main promise of interconnecting these heterogeneous networks is to provide high performance in
achieving a high data rate and support real time applications. These services require various networks (such as
CDMA2000 and Wireless LAN) to be integrated into IP-based networks, which further require a seamless
vertical handoff to 4th generation wireless networks. When a mobile host (MH) changes its point of attachment,
its IP address gets changed. MH should be able to maintain all the existing connections using the new IP
address. This process of changing a connection from one IP address to another one in IP network is called
handoff. Vertical handoff is switching from one network to another while maintaining the session. Vertical
Handoff (VHO) is a major concern for different heterogeneous networks. VHO can be user requested or based
on some criteria already designed by the researcher of that particular algorithm. The main objective is to
implement efficient & effective handoff scheme between two heterogeneous network ie. 802.11 WLAN &
CDMA
This document provides an overview of mobile computing. It discusses the challenges of mobile computing including constrained resources, security, and mobility. It also covers the different generations of mobile communication technologies, including 1G, 2G, 3G, and 4G. For each generation, it provides details on the technologies used, features, data transmission speeds, and drawbacks. It discusses multiplexing techniques like FDMA, TDMA, and CDMA used in early cellular systems. Finally, it covers topics like applications of mobile computing and characteristics of mobile environments like ubiquity and personalization.
This document discusses mobile computing and mobile databases. It begins by defining mobile computing as allowing users to access network services from anywhere using portable computers connected via wireless networks. It then discusses challenges of mobile computing like limited bandwidth, intermittent connectivity, and changing locations. The document outlines the general architecture of mobile computing including mobile units, base stations, and wireless communication. It describes key aspects of mobile databases like being located on mobile devices and communicating with central databases. Finally, it discusses characteristics of mobile environments like high latency, limited battery life, and unreliable connectivity that must be addressed in mobile applications and databases.
The document provides an introduction to mobile computing, including:
- Mobility and wireless connectivity will enable new applications and markets by making information accessible anywhere.
- Mobile computing allows users to access network services from any location and describes different types of mobile devices and networks.
- Applications of mobile computing are discussed in several fields like vehicles, emergencies, business, and more where mobility is important.
- Limitations of mobile computing include resource constraints, interference, bandwidth limitations, dynamic network changes, and security issues.
- A reference model is presented showing the protocol stack layers needed to support mobile communication between devices.
AN OVERVIEW: DAKNET TECHNOLOGY - BROADBAND AD-HOC CONNECTIVITY | J4RV4I1009Journal For Research
DakNet, is an ad hoc network and an internet service planted on the applied science, which uses wireless technology to provide an asynchronous digital connectivity, it is the intermediate of wireless and asynchronous service that is the beginning of a technical way to universal broadband connectivity. The major process is it provides the broadband connectivity as wider. This paper broadly describes about the technology, architecture behind and its working principles.
Mobile computing allows transmission of data without a fixed connection by using cellular networks. It has evolved from walkie-talkies and two-way radios to today's smartphones that can perform most computer functions wirelessly. Mobile devices work by transmitting radio signals through cell towers and wireless networks to other devices. While portable and socially interactive, mobile computing faces security issues when using public networks, limited battery life, potential health risks from radiation, and difficulty interfacing with small screens.
This document reviews protocols for mobile ad hoc networks (MANETs). It discusses how MANETs are self-configuring, decentralized wireless networks that allow nodes to communicate through wireless links. Routing in MANETs is challenging due to the frequent changes in network topology as nodes move. The document classifies MANET routing protocols as proactive, reactive, or hybrid and discusses examples of each type. It also reviews the evolution of MANET research from early packet radio networks to today's standards and ongoing work. Key challenges for MANET implementations include dynamic topologies, device discovery, and limited bandwidth and power.
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document provides an overview of mobile computing. It discusses the challenges of mobile computing including constrained resources, security issues, and mobility. It also describes generations of mobile communication technologies and various multiplexing techniques used in mobile networks like TDMA, FDMA, and CDMA. Resources in mobile computing are limited due to factors like limited power, storage, bandwidth, and wireless communication which present design challenges. Security and mobility also introduce additional challenges for mobile computing systems.
Mobile Adhoc Network (MANET) Routing Protocols Analytical StudyIOSR Journals
This document provides an analytical study of routing protocols for mobile ad hoc networks (MANETs). It begins with definitions of MANETs and discusses their key characteristics including dynamic topology, limited energy/bandwidth, and security vulnerabilities. The document then examines the core functions and categories of MANET routing protocols. It analyzes several table-driven proactive protocols including DSDV and WRP, and on-demand reactive protocols including DSR, AODV, and TORA. Tables compare the protocols on metrics like routing structure, memory overhead, convergence time and advantages/disadvantages. The analysis found that different protocols have tradeoffs between overhead, adaptation to mobility, and scalability.
Sachpazis_Consolidation Settlement Calculation Program-The Python Code and th...Dr.Costas Sachpazis
Consolidation Settlement Calculation Program-The Python Code
By Professor Dr. Costas Sachpazis, Civil Engineer & Geologist
This program calculates the consolidation settlement for a foundation based on soil layer properties and foundation data. It allows users to input multiple soil layers and foundation characteristics to determine the total settlement.
Online train ticket booking system project.pdfKamal Acharya
Rail transport is one of the important modes of transport in India. Now a days we
see that there are railways that are present for the long as well as short distance
travelling which makes the life of the people easier. When compared to other
means of transport, a railway is the cheapest means of transport. The maintenance
of the railway database also plays a major role in the smooth running of this
system. The Online Train Ticket Management System will help in reserving the
tickets of the railways to travel from a particular source to the destination.
Better Builder Magazine brings together premium product manufactures and leading builders to create better differentiated homes and buildings that use less energy, save water and reduce our impact on the environment. The magazine is published four times a year.
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Data Communication and Computer Networks Management System Project Report.pdfKamal Acharya
Networking is a telecommunications network that allows computers to exchange data. In
computer networks, networked computing devices pass data to each other along data
connections. Data is transferred in the form of packets. The connections between nodes are
established using either cable media or wireless media.
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1. MOBILE COMPUTING
INTRODUCTION
S J Savitha
Assistant Professor
Computer Science and Engineering
Sri Ramakrishna Institute of technology
1
2. WHAT IS MOBILE COMPUTING?
What is computing?
Operation of computers (according to oxfords
advance learner’s dictionary)
What is the mobile?
That someone /something can move or be moved
easily and quickly from place to place
What is mobile computing?
Users with portable computers still have network
connections while they move
2
3. Mobility provides the capability to change location
while computing goes on.
Computing denotes the capability to carry out
processing automatically related to service provided
to the user.
3
MOBILE COMPUTING = MOBILITY + COMPUTING
4. A simple definition could be:
Mobile Computing is using a computer (of one kind
or another) while on the move
Another definition could be:
Mobile Computing is when a (work) process is
moved from a normal fixed position to a more
dynamic position.
A third definition could be:
Mobile Computing is when a work process is
carried out somewhere where it was not previously
possible.
4
5. Mobile Computing involves the invocation of
applications running on remote servers.
Mobile Computation
The main concept involves in Mobile Computing :
1.Mobile Communication
2.Mobile Software
3.Mobile Hardware
5
6. MOBILE COMMUNICATION:
6
Mobile communication refers to the infrastructure
put in place to ensure that reliable communications
goes on without any collision with other existing
systems.
7. MOBILE SOFTWARE
Mobile software is the actual program that runs on
the mobile hardware. It deals with the
characteristics and requirements of mobile
applications.
7
8. MOBILE HARDWARE
Mobile hardware includes mobile devices or device
components that receive or access the service of
mobility.
These devices are configured to operate in full-
duplex, whereby they are capable of sending and
receiving signals at the same time.
8
10. TELECOMMUNICATION NETWORKS
A Telecommunication networks is an arrangement
of computing and telecommunication resources for
communication of information between distant
locations.
Components :
1. Terminals
2.Computers
3.Telecommunication links
4.Telecommunication equipment
5.Telecommunication Software
10
18. WIRELESS NETWORKING
A wireless network is any type of computer
network that uses wireless data connections for
connecting network nodes.
Wireless means transmitting signals using radio
waves as the medium instead of wires.
18
19. Wireless technologies are used for tasks as simple
as switching off the television or as complex as
supplying the sales force with information from an
automated enterprise application while in the field.
19
20. CHARACTERISTICS OF WIRELESS NETWORKS
Mobility
Reachability
Simplicity
Maintainability
Roaming Services
New Services
20
21. MOBILE COMPUTING VS WIRELESS
NETWORKING
Two terms are not synonymous.
Mobile computing essentially denotes accessing
information and remote computational services
while on the move.
Wireless networking provides the basic
communication infrastructure necessary to make
this possible.
Thus mobile computing is based on the wireless
networking and helps to invoke the computing
services on remote servers.
21
22. Instead of studying the different aspects of mobile
computing applications, designs and development,
we need to have a good knowledge of the basics of
wireless communication technologies.
Wireless networks are increasingly replacing the
traditional networks.
Wireless network can be classified into two basic
types :
1. Extension of wired networks.
2. Ad hoc networks.
22
23. The extension of wired networks uses the fixed
infrastructures such as base stations to provide
essentially single hop wireless communication with
a wired networks.
Example :
Wireless LAN(WLAN) that implements the
IEEE 802.11 protocol.
23
24. An Ad hoc network does not use any fixed
infrastructure and is based on multi-hop wireless
communication.
An ad hoc network is also called as a Mobile Ad
hoc Network(MANET).
24
37. CHARACTERISTIC OF MOBILE COMPUTING
Ubiquity
It means –any time every where. This
characteristic make the user to compute at
anytime he needs and can compute anywhere
he goes.
Location Awareness
A mobile devices with global positioning system
can transparently provide information about the
current location of a user to a tracking station.
Adaption
Adaption is the ability of the mobile devices to
adjust to bandwidth fluctuation without
distributing the user.
37
38. Broadcast
Due to the broadcast nature of mobile computing,
efficient delivery of data can be made simultaneously to
the hundreds of user.
Personalization
Services in mobile environment can be easily
personalized according to a user’s profile. This is
required to let the users easily avail information with
their handheld devices.
38
39. STRUCTURE OF MOBILE COMPUTING
APPLICATION
A mobile computing application is usually structured
in terms of the functionalities implemented.
The structure of mobile computing can be
implement with three tiers. The three basic layers
are
1.Presentation layer(Tier-1)
2.Application layer(Tier-2)
3.Data layer(Tier-3)
39
42. PRESENTATION TIER
The topmost level of a mobile computing
application concerns the user interface. A good user
interface facilitates the users to issue requests and
to present the results to the them meaningfully.
The computing codes of this layer usually runs on
the client’s computer including web browsers and
client programs to give information to the user and
also to collect data from the user.
42
43. APPLICATION LAYER
The application layer makes logical decisions and
perform calculations according to the user’s query.
It also moves and processes data between the
presentation and data layers.
This application layer is implemented using
technology like java, .NET services etc.,
This layer is database independent and all these
functionalities are implemented on a fixed server.
43
44. DATA LAYER
Data layer provides the basic functions with data
like storing data, retrieve data and manipulating
data.
Data layer has a database and all the information is
stored and retrieved from the database.
This layer is also implemented on a fixed layer.
44
46. MEDIUM ACCESS CONTROL(MAC)
The MAC protocol is a sublayer of the data link
layer protocol and it directly invokes the physical
layer protocol.
The MAC layer emulates a full-duplex logical
communication channel in a multi-point network.
This channel may provide unicast, multicast or
broadcast communication service.
The MAC sublayer provides addressing and
channel access control mechanisms that make it
possible for several terminals or network nodes to
communicate within a multiple access network that
incorporates a shared medium.
46
47. The primary responsibility of a MAC protocol is to
enforce discipline in the access of a shared channel
when multiple nodes contend to access that
channel.
MAC protocol must ensure that no node has to wait
for a long time, before it is allowed to transmit.
The two objectives of MAC protocol are :
1.Maximization of the utilization of channel
2.Minimization of average latency of
transmission.
47
48. PROPERTIES OF MAC PROTOCOL
It should implement some rules that help to
maintain discipline when multiple nodes contend for
a channel.
It should help maximize the utilization of the
channel.
Channel allocation need to be fair.
It should be capable of supporting several types of
traffic having different maximum and average bit
rates.
It should be robust.
48
49. At present, IEEE 802.11 has emerged as a popular
and standard MAC protocol for wireless networks.
Wireless networks can be classified into two
categories :
1.Infrastructure-based wireless networks (WLAN)
2.Infrastructure-less wireless networks.(MANET)
The MAC protocols for the above two environments
have many things in common, MAC protocols for
infrastructure –less networks are much more
complex.
49
50. WIRELESS MAC PROTOCOLS : ISSUES
HIDDEN and EXPOSED Terminal problem
In Infrastructure-less networks , the issue of hidden
and exposed terminals make a MAC Protocol
extremely inefficient.
The hidden terminal problem arises when at least
three nodes (Ex : A, B, C) communicates among
each other.
50
Hidden terminal problem
51. B is in the radio range of A and also in the radio
range of C. However, the nodes A and C are not in
the range of each other.
If both A and C start to transmit a data to B at the
same time, the data received at node B would get
garbled.
Such a situation arises because A and C are
“hidden” from each other.
In this situation, when one node starts to sense the
medium before transmission, it cannot sense that
the other node is also transmitting.
This creates a very difficult and important arbitration
problem.
51
52. Exposed Terminal problem :
In exposed terminal problem, MAC protocols
usually inhibit transmission when transmission from
another terminal is detected.
A node will not be able to transmit data to any node
when B is transmitting to C.
The problem occurs because A is exposed to B’s
transmission.
52
Exposed terminal problem
53. TAXONOMY OF MAC PROTOCOLS
A large number of MAC protocols have been
proposed. These MAC protocols can be broadly
divided into three categories:
1.Fixed Assignment schemes
2.Random Assignment schemes
3.Reservation-based Schemes
The Fixed assignment schemes are called as circuit-
switched schemes. The random assignment and
reservation based schemes are called as packet-
switched schemes.
53
55. FDMA :
o In FDMA, the available bandwidth is divided into
many narrower frequency bands called channels.
o Each user is allocated a forward link(channel) for
communicating from it(mobile handset) to base
station
A reverse channel for communicating from the BS
to it.
55
56. Two unique frequency –transmitting and receiving
signal
No other user would be allocated the same
frequency band to make a call
Unused transmission or when no user is allocated a
band it goes to idle or waste
FDMA does not achieve high channel utilization
56
57. TDMA
Multiple nodes are allocated different time slots to
access the same physical channel
Timeline is divided into fixed sized time slots and
these are divided among multiple nodes who can
transmit
All sources use the same channel but take turns in
transmitting
Round robin method is been used with each user
being assigned one time slot per frame
Unused time slots go idle leading low channel
utilization
57
59. CDMA
Multiple users are allocated different codes that
consists of sequence of 0 and 1 to access the same
channel.
Different users who have assigned separate codes
are multiplexed on the same physical channel.
A code for a user should be orthogonal to the code
assigned to other codes.
Bandwidth >space allocated to each
transmission.
59
60. RANDOM ASSIGNMENT SCHEMES
Connectionless Packet Switched Scheme.
No resource reservation are made.
The node transmit as soon as they have a packet to
send.
CATEGORIES
1.ALOHA
2. Slotted ALOHA
3.CSMA
4.CSMA/CD
5.CSMA/CA 60
61. ALOHA SCHEME
o Simple communication scheme
o The basic ALOHA Scheme is called as Pure ALOHA (
simple protocol).
o If a node has data to send it begins to transmit.
o Does not check whether the channel is busy before
transmitting.
o If the frame is successfully reaches the next frame is
sent, if it fails it has to be resent.
o It works only when small amount of sender data is sent.
o Collision occurs when transmission is high.
61
62. Improvement over pure ALOHA is slotted ALOHA.
Slotted ALOHA
Time is divided into equal time slots in which
packets are sent. By this packet size is restricted
Only at the beginning of a slot packet can be sent
Beacon signals for transmitting the data
if the number of contending to send data is high,
this protocol does not work
62
63. CSMA SCHEME
Popular MAC attribution technique.
A node senses the medium before starting to
transmit.
Two popular extensions are
1. CSMA/CD
2. CSMA/CA
CSMA/CD
If it sense the channel to be free and transmit the
data still collision occurs
Received signal from other nodes would be too
weak compared to its own signal and can be
masked by noise.
63
64. Destination node will have corrupted frame after it
computes .
But in wired network when a node is detected with
collision it immediately stops transmitting
Minimizing channel wastage.
64
65. CSMA/CA
Avoidance scheme works better compared to
collision detection in wireless.
When it is released after a packet transmission
Not only one node but several nodes might be
wanting to transmit.
These nodes be monitoring the channel and waiting
it to be free.
To reduce the transmission of nodes at a time, the
node is set to wait for random time and sense the
medium again before transmission.
65
66. RESERVATION BASED SCHEMES
RTS/CTS is the basic form of reservation
scheme.(RTS –Ready To Send , CTS –Clear To
Send)
Sender transmits an RTS packet to the receiver
before the actual data transmission.
Receiver sends a CTS packet, and the actual data
transfer commences after that.
Examples:
MACA,MACAW,MACA–BI ,PAMAS,DBTMA,
MARCH,S-MAC.
66
67. MACA
MACA- Multiple Access Collision Avoidance.
It solves the hidden/exposed terminal by
transmitter power.
With MACA, A does not start its transmission at
once, but sends a request to send (RTS) first.
67
68. 68
B receives the RTS that contains the name of
sender and receiver, as well as the length of the
future transmission. This RTS is not heard by C, but
triggers an acknowledgement from B, called clear
to send (CTS).
The CTS again contains the names of sender (A)
and receiver (B) of the user data, and the length of
the future transmission.
This CTS is now heard by C and the medium for
future use by A is now reserved for the duration
of the transmission.
69. After receiving a CTS, C is not allowed to send
anything for the duration indicated in the CTS
toward B.
A collision cannot occur at B during data
transmission, and the hidden terminal problem is
solved.
Still collisions might occur when A and C transmits
a RTS at the same time. B resolves this contention
and acknowledges only one station in the CTS. No
transmission is allowed without an appropriate
CTS.
69
70. Now MACA tries to avoid the exposed terminals in
the following way:
With MACA, B has to transmit an RTS first
containing the name of the receiver (A) and the
sender(B).
C does not react to this message as it is not the
receiver, but A acknowledges using a CTS which
identifies B as the sender and A as the receiver of
the following data transmission.
70
71. C does not receive this CTS and concludes that A is
outside the detection range. C can start its
transmission assuming it will not cause a collision
at A.
The problem with exposed terminals is solved
without fixed access patterns or a base station.
71
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