MOBILE COMPUTING & MOBILE COMMUNICATION SYSTEMS

What is Mobile Computing? Wireless Communication Systems Mobile Communication Systems Architecture

Key Technologies of Mobile Computing Applications

WHY MOBILE COMPUTING ?

People are mobile

WHY MOBILE COMPUTING ?

Devices are mobile

WHAT IS MOBILITY?

A person who moves between different geographical locations between different networks between different communication devices between different applications

WHAT IS MOBILITY?

Mobile computing is about both physical and logical computing entities that move Physical entities

computers change locations Logical entities

a running user application or a mobile agent migrating over internet

BUZZWORDS – NOMADIC-MOBILE-UBIQUITOUS

Nomadic computing refers to limited migration migration is within a building at a pedestrian speed

interleaved pattern of user relocation and indoor connections

users carrying laptop with wireless access are engaged in nomadic computing

BUZZWORDS – NOMADIC-MOBILE-UBIQUITOUS

Mobile computing requires wireless h/w to support outdoor mobility and handoff from one h/w to the next at a pedestrian or vehicular speed

traveler in car using laptop / smart phone / mobile device connected with a GSM/WCDMA/HSPA phone engaged in mobile computing

Ubiquitous computing or pervasive computing refers to access to computer network all the time at any location by any person

can not be realized unless mobile computing matures

RELATIONSHIP – NOMADIC-MOBILE-UBIQUITOUS

My Dream of Futurehttp://www.youtu.be/ujk1cprLpD8

Social Web of Thingshttp://www.youtu.be/i5AuzQXBsG4

Imagine Everything was Linkedhttp://youtu.be/igsJxXMssGA http://www.youtu.be/__pkZ4-kNvYhttp://www.youtu.be/tvpRJrQ8Z2c

HETEROGENEOUS WIRELESS COMMUNICATION WORLD

DAB: Digital Audio BroadcastVHE: Virtual Home Environment

DVB-T: Digital Video Broadcast TerrestrialUMTS: Universal Mobile Telecommunication System

HETEROGENEOUS WIRELESS COMMUNICATION WORLD

Heterogeneous wireless networks consists of Cellular networks WLAN networks other access technologies

Users should be able to access various services from various networks with varying properties in terms of data rates, SNR, latency, coverage, price etc.

Multiple devices or multi-mode devices may be used to access various services which add to the complexity of the system

Mobile communication in such a scenario requires automatic rearrangement of communication and services

These adaptive services need to be centered around the user since multiple networks and operators may be present

NATURAL EVOLUTION OF COMPUTING

Freedom from Collocation

More Flexible Resource Usage

CHALLENGE

Physical location of mobile is not the network address (address migration) existing applications send packets to a fixed network address

need to support dynamically changing “local” addresses as mobile device moves through network

how do we route the message to a mobile host

Internet communityMobile IP deals with location of mobile host

Mobile IP assumes connectionless, packet switching scenario

Mobile IP specification: home environment tracks mobile device’s current location through registration procedure

Cellular communitybased on location management of cellular phone users

it deals with connection oriented communication (motivated by issues in call-setup in telephony)

trade-off between searching and informinginforming is a responsibility of the mobile unit when it migrates

extreme situationsmobile unit never informs - works for units receiving few messages and for units which don't move during receiving

mobile unit always informs - works well for units receiving messages frequently

CHALLENGE

Ad hoc routing algorithms Ad hoc networks arise in rapid deployment scenariosemergency disaster managementmilitary operation in remote sitesbusiness meeting venues without infrastructure support

Routing algorithmsAODV, DSR, DSDV, TORA, FSR, LAR, ABR, etc.

CHALLENGE Harsh communications environment

lower bandwidth / higher latencygood enough for video conferencing?

variable bandwidth: applications adaptation to changing quality of connectivityhigh bandwidth, low latencyhigh bandwidth, high latencylow bandwidth, high latency

higher error rates: congestion, interference, etc.

more frequent disconnection performance depends on density of nearby users but frequency reuse architecture helps

network failure is common

CHALLENGE

Two modes of information dissemination Publish

data is filtered by client, server provides directory information for assisting the filtering

advantageshot spots can be broadcast frequently - which saves energy at client, avoid congestion.

Provide on demand

CHALLENGE

Services providing issues Interoperability and adaptability to h/w environments ranging from high to low bandwidths and wireless communication links

Energy efficient data access Support for mobility and disconnection

CHALLENGE

Handoff management a mobile host moves from one cell to another while being connected

undesirable featurescall droppingping-pong handoffs

vertical handoff among heterogeneous networks

HETEROGENEOUS WIRELESS COMMUNICATION WORLD

DAB: Digital Audio BroadcastVHE: Virtual Home Environment

DVB-T: Digital Video Broadcast TerrestrialUMTS: Universal Mobile Telecommunication System

CHALLENGE

Security concerns Authentication is critical

normal network point of attachment is a wall tap

wireless access makes network attachment too easy

Exposure to over-the-air wiretappingany transmitter can also be a receiver!some wireless networks provide secure airlinks (e.g., CDPD)

made more difficult by spread spectrum technologies

Mobile agent security