Lecture Materials Mobile Computing By Bintang Eka Putera

Background 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

New Forms of Computing Distributed Computing (Client/Server) Wireless Computing Nomadic Computing Mobile Computing Ubiquitous Computing Pervasive Computing Invisible Computing

Comparison to Wired Network Mobile Networks Wired Networks high bandwidth low bandwidth variability can listen on wire high power machines high resource machines need physical access(security) low delay connected operation low bandwidth high bandwidth variability hidden terminal problem low power machines low resource machines need proximity higher delay disconnected operation

Nomadic computing refers to limited 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

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

Nomadic – Mobile – Ubiquitous Applications Network Computing Systems No Network Fixed Wireless Network Nomadic Computing Ubiquitous Computing Wireless Network Mobile Computing

Heterogeneous Wireless Communication World

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

Wireless Communication Technology

Main Topics What is Mobile Computing? Wireless Communication Systems Mobile Communication Systems Architecture Key Technologies of Mobile Computing Applications

What is Mobile Computing? A simple definition could be: Mobile Computing is using a computer (of one kind or another) while on the move

What is Mobile Computing? Another definition could be: Mobile Computing is when a (work) process is moved from a normal fixed position to a more dynamic position.

What is Mobile Computing? A third definition could be: Mobile Computing is when a work process is carried out somewhere it was not previously possible.

What is Mobile Computing? Mobile Computing is an umbrella term used to describe technologies that enable people to access network services anyplace, anytime, and anywhere.

Wireless Communications First thing that comes in mind that has anything to do with wireless is … RADIO! Radios are Listeners not Speakers ! Radio signals received in Limited Area Radios use various frequencies Radio Communication is Analog

Wireless Communications First thing that comes in mind that has anything to do with wireless is … So HOW TO send Digital data on {Analog / Digital} Signal?

Wireless Communications We need devices that Can Transmit (Tx) & Receive (Rx) Can Interpret Analog signal Can convert Analog signal to Digital data Can send and receive signal in some Area Can connect to other devices in this Area Can stay connected while moving Would have “enough” bandwidth for Tx

• Devices operate on various Frequencies • Two devices can “Talk” on same Frequency • Many devices need many frequencies Wireless Communications Freq (Hz) LF MF HF VHF UHF SHF EHF 105 106 107 108 109 1010 1011

Security concerns Authentication is critical normal network point of attachment is a wall tap wireless access makes network attachment too easy

Security concerns Exposure to over-the-air wiretapping any transmitter can also be a receiver! some wireless networks provide secure airlinks (e. g. , CDPD/Cellular Digital Packet Data) made more difficult by spread spectrum technologies

Security concerns Mobile agent security