Transcript
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Mobile Multimedia CommunicationsAn Emerging Technology

Presented by:

Dr. M. Mahfuzul Islam

Department of Computer Science and Engineering

Bangladesh University of Engineering and Technology

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Presentation Objectives

What is Mobile Multimedia

Communication?

Wireless networks: An Emerging

Technology.

Research Problems

Conclusions

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Mobile Multimedia Communications

MSC

PSTN

Wireless Connection

Optic Fibre

Wired Connection

Movie Server

Base Station

Integrate voice, audio, text and video.

Connectivity

Combine Wireless and wired medium.

Allow Terminal Mobility and Personal Mobility

Combine Telecommunications and Computing Technology.

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Wireless Technology: the new vision

Current wireless uses Wireless long distance Wireless LANs Wireless local Loops

(WLLs) Personal area networks

(PANs) M-Commerce

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Wireless Technology: the new vision

Wireless Long Distance

1G AnalogAMPSTACSNMTRTMS

2G narrowband DigitalGSM

IS-54/136 TDMAISS-85/cdmaOne

PDC

2G+ or 2.5GVoice and DataGPRS, HSCDS

GSMIS-136A & 8

TDMAIS-95c cdmaOne

3G Broadband Digital

W. CDMAUWC-136cdma2000

VoiceVery small

dataAmerican Roaming

Enhanced Voice

some dataInternational

Roaming

VoiceEnhanced data

E-mail Internet

Broadband dataVideo

Fast Internet Remote Access

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Wireless Technology: the new visionWireless Long Distance: GSM

The most popular 2G cellular standard developed to cater

voice services and data delivery using digital

modulation.

Development background:

Developed by Groupe Spéciale Mobile (founded

1982) which was an initiative of CEPT (Conference

of European Post and Telecommunication).

In 1989, ETSI (European Telecommunications

Standards Institute) took the control of GSM and

defined new acronym “Global System for Mobile

Communications.”

Commercial use has been started since 1991.

Features of GSM Standards:

Supports international roaming and

handheld terminals.

Good subjective speech quality and

wide-range of new services.

Low cost (?).

Compatible with other systems, say

ISDN and PSTN.

2.5G Cellular: Extends the 2G technologies – GSM, TDMA, CDMA. GPRS (general packet

radio systems) technology is used to add data capacity.

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Wireless Technology: the new vision

Wireless Long Distance

3G Cellular: The goals of 3G are to

provide- WANs for PC and multimedia, allowing for bandwidth on demand. flexibility to support multiple standards integrate fixed wireless access services, satellite services and cellular at data rates 384 kbps for mobile, and 2 mbps for fixed.

CDMA is the universal standard for 3G, but face the same pricing issue at 2.5G (time basis charge). Court battles over the leased spectrum. costs to deploy not seen as tenable.

4G Cellular: Broadband IP could provide

4G services (since 2003).

Users pay for different kind of services.

The service is IP based and looks like wired services accessed via a browser.

New entrants arelooking for 3Galternatives.

VSAT (very small aperture terminal): Stationary wireless

Broadband is best provided by VSAT.

Many country is taking off. Small VSAT dishes, speed

0.5 mbps.

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Base Transceiver

System (BTS)

Base Transceiver

System (BTS)Base Station

Controller (BSC)

Base Station

Controller (BSC)

Base Station (BS)

VLR HLR

EIR AuC

Mobile Switching Centre

(MSC)

PSTN

Other

GSM

MobileTerminal (MT)

Wireless Connection

P2P Wireless or optic fiber connection

There are three main components of GSM networks:

Mobile Terminal (MT) Mobile equipment for transmitting and receiving signals. Subscriber Identity Module (SIM) for storing necessary permanent and temporary data.

Base Station (BS) Base Transceiver System (BTS) for

transmitting and receiving signals; and manipulating signals

Base station Controller (BSC) for assigning and managing resources, controlling handoff and power level, etc.

Mobile Switching Centre (MSC) Manage communications, mobility, and billing information.

Home Location Register (HLR): central master database for users under the MSC. Visitor location Register (VLR): Local database for the users currently under the domain of MSC. Authentication Center (AuC): Authenticate mobile terminals and encrypt user data. Equipment Identity Register (EIR): register MTs and locked stolen or malfunctioning MTs.

Wireless Technology: the new visionWireless Long Distance: GSM Network Components

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Wireless Technology: the new vision

Wireless LAN

Wireless LAN Used within a building or among buildings on a campus. Wireless LANs are not generally replacing existing wired LANs but extending

them to portable devices. Example: In hospitals, doctors and nurses can use handheld or notebook computers to record patient

data at the bedside, which is faster than using a wired computer.

WLANs use two technologies: infrared and microwave.

Cannot penetrate solids such as walls, ceiling, dust or rain. So, transmitter and receiver must be in line of sight.

Microwave and radio-frequency (RF) are the most popular WLAN technology because the signals can go through the walls.

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Wireless Technology: the new vision

Wireless LAN

Wireless LAN use two topologies: peer-to-peer and client-server. Peer-to-peer: each unit communicate with every other units.

Less expensive because the system has no central controlling unit.

Performance decreases as traffic increase because more and more collisions occur.

Client-Server: Server is the central coordinating node. It communicates with the clients wirelessly and links to a wired LAN on behalf of those clients.

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Wireless Technology: the new vision

Wireless LAN

Wi-Fi is the 802.11b wireless Ethernet standard that transmits up to 11 Mbps connection is easy. Wi-Fi networks run in unlicensed bandwidth. Appear in a place where people congregate such as airports, hotels, conference centers, and coffee houses. For many people, WLAN services could be equivalent to 3G at about 1/13th the current cost.

Self-organizing Mesh is a new idea in WLAN arena Operate in peer-to-peer mode A message is routed to the nearest access point – the closest device – which routes it to the next nearest point, and so on. The unusual phenomenon is that the more users, the more capacity. This technology could strongly influence the future of wireless.

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Wireless Technology: the new vision

Wireless Local Loop: With the goal of replacing the wireline link. This “fixed wireless” solves “the last mile” problem. Use RF technology between a home or business and a telephone company’s central office. One approach is to place antennas on light posts to form a wireless mesh. Fixed wireless is being used in developing countries and remote locations in place of wire because these networks are more rapidly deployed and less costly that buying cables.

Some developing countries are bypassing wiring altogether.

Wireless PAN (Personal Area Network): A short distance network – about 30 feet (10 meters).The main technologies used are infrared and Bluetooth. This new kind of network could be used to synchronize laptop and a PDA, link several laptops in a rooms, etc.

M- Commerce: Conduct commerce digitally from wireless devices.

Location-based services and personalization are important part of wireless economy. Due to small antennas and low power, the handheld device can’t send signals to satellite for measuring location using GPS.

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Research Challenges

Wireless Resources

…………….Bandwidth in wired media

600 Mbps for 1 ATM line 600 Mbps for 1 ATM line

Bandwidth in wireless media384 Kbps for cell radius 10 km ( 2G / 2.4G) /

2 Mbps for cell radius < 100 m (Pico-cell, 3G)

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Most GSM Networks operate at 900 MHz and/or 1800MHz, 850 MHz and/or 1900MHz in Parts of Americas (including USA and Canada).

900 MHz Frequency Band

Uplink

Downlink

124 carriers

890MHz 915MHz 935MHz 960MHz

Downlink Uplink

124 carriersEach Carrier has 200KHz Frequency band

TDMA divides each RF channel (i.e., carrier) to 8 voice Channel

t1 t1 t2

t2 t3 t3 t4

t4 t5 t5 t6

t6 t7 t7 t8

t8

Time-slots

Time slot duration 577 µs

TDMA Frame: Each frame contains 8 time slots. Channel data rate: 270.833 kbps Frame duration: 4.615 mS

There are two types of logical channels: Traffic channels

Signaling Channels – for broadcasting, common control, and dedicated control.

Research ChallengesWireless Resources: GSM

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Research Challenges

Wireless Resources

When an active mobile moves from one cell to another (handoff call), then resources must be available at that cell to continue the call, otherwise the call will dropped.

From the users perspective,

“Dropping an ongoing call is more undesirable to the user than blocking a new call.”

Reserving resourcesReserving resources in neighbouring cells is the only in neighbouring cells is the only solution to this problem.solution to this problem.

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Research Challenges

Open Research Problem on Wireless Resources

Resources can be increased by using Smart Antenna.

Efficient use of bandwidth by exploiting mobility information.

Developing efficient resource allocation algorithms.

Efficient use of Radio frequency waves.

Exploration of new radio frequencies for communication.

The Cell Structure for K = 7

12

34

5

67

12

34

5

67

12

34

5

67

D

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Research Challenges

Is Wireless Secured?

In favor of Security Both wired and wireless use the IP protocol. Signals fade fast when they travel through the air. Eavesdroppers need

special equipment to pick up radio signals from far away. Data are encrypted before sending.

Not Secured Data inside the handheld device is not in encrypted format. Hackers may

successful in remote login and collect data. Data sent spread in air, open to all (how can we get 100% secured encryption

technique).

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Research Challenges

Is Wireless Safe ?

Microwave frequencies are more dangerous than radio-wave frequencies, because microwave cause molecule to vibrate faster, causing heat as the molecules rub against each other. The power limit on cell-phones, wireless modems, and WLANs (3 watts) aims to protect people from this short-term microwave heating phenomenon. Some studies shows that long-term effects from low-level vibration do not raise body temperature, but damage to DNA, which may cause disease like cancer.

Electromagnetic radiation from power lines, electronic appliances, and computers can interfere with the body’s bio-electromagnetic fields, causing an imbalance. These imbalances leave people feeling drained, fatigued, and stressed out. Although our body can rebalance disruptions caused by occasional exposure to electromagnetic radiation, frequent exposure will lower body’s immunity and causes diseases.

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Research Challenges

Other Open Research Problems on Cellular Network

Development of Localization Algorithms

Handoff Management and Data Migration Policies

Device Registration and Call Delivery.

Security

Architecture for Providing Internet Services

Developing smart devices

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Research Challenges

Other Areas for Research

Development of Smart Devices: Developing smart-devices for reducing communications.

Wireless Ad-hoc Network: Designing Ad-hoc network along with tackling its IP addressing, routing and security problem.

Wireless Sensor Network: Designing Wireless sensor networks along with its data transferring, security and localization problem.

Wireless LAN and WAN: Development of Infrastructure, smart devices and reliable and secured policies for data communication.

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Conclusions

Mobile Multimedia Communication is the most emerging wireless

technology.

Wireless Networks are going to replacing its counterpart wired network

rapidly.

Introduction of Smart Devices and continuing development of algorithms

enable tremendous growth of mobile communications.

Wireless Network provides moderate level of security.

Capacity is the main limitation of Wireless networks.

Indeed !

Wireless and Optical Network will survive only in the next generation !

Indeed !

Wireless and Optical Network will survive only in the next generation !


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