Communication is one of the integral parts of science that has always been a focus point for exchanging information among parties at locations physically apart. Afte its discovery, telephones have replaced the telegrams and letters. Similarly, the term`mobile' has completely revolutionized the communication by opening up innovative applications that are limited to one's imagination. Today, mobile communicationhas become the backbone of the society. All the mobile system technologies have improved the way of living. Its main plus point is that it has privileged a common mass of society.
Basic Mobile communication structure
mobile communication is location independent (personal) communicationmore or less possible mobility depends on
network coverage range of wireless access availability and reach ability of access points
Rule of thumb: The more mobile, the more expensive
Aspects of mobility:
User mobility: users communicate (wireless) “anytime, anywhere, with anyone”
Device portability: devices can be connected anytime, anywhere to the network
Wireless vs. mobile Examples û û stationary computer û ü notebook in a hotel ü û wireless LANs in historic buildings ü ü Personal Digital Assistant (PDA)
Types of mobile networks:
WWAN(Wireless Wide Area Network)A Wireless Wide Area Network or WWAN is wireless connectivity to the Internet achieved through using cellular tower technology(a site where antennas and electronic communications equipment are placed, usually on a radio mast, tower or other high place, to create a cell in a cellular network).
Technology: GSM,
WMAN (Metropolitan Area Network) A wireless communications network that covers a geographic area such as a city or suburb.
Standard: IEEE 802.16Technology: WiMAX
WLAN(Local Area Network) It provides wireless network communication over short distances using radio or infrared signals instead of traditional network cabling.
Standard: IEEE 802.11 Technology: WiFi
WPAN(Personal Area Network)A wireless personal area network (WPAN for short) is a low-range wireless network which covers an area of only a few dozen metres.
Standard: IEEE 802.15 Technology: Bluetooth
Examples of wireless access technology
Examples of wireless access technology which can be seen under the aspect of mobility:o terrestrial cellular networks, e.g. GSM, UMTS, CDMA2000, ...o wireless LAN 802.11a,b,g,no WiMAX 802.16o Bluetootho satellite communication,o trunked radio, e.g. TETRA
The demand for mobile communication creates the need for integration of wireless networks into existing fixed networks:
local area networks: standardization of IEEE 802.11, ETSI (HIPERLAN)
Internet: Mobile IP extension of the internet protocol IP wide area networks: e.g., internetworking of GSM and ISDN
ApplicationsVehicles transmission of news, road condition, weather, music via DAB personal communication using GSM position via GPS local ad-hoc network with vehicles close-by to prevent accidents, guidance system,
redundancy vehicle data (e.g., from busses, high-speed trains) can be transmitted in advance for
maintenance Emergencies
early transmission of patient data to the hospital, current status, first diagnosis replacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc. crisis, war, ...
Typical application: road traffic
Travelling salesmen direct access to customer files stored in a central location consistent databases for all agents mobile office
Replacement of fixed networks remote sensors, e.g., weather, earth activities flexibility for trade shows LANs in historic buildings
Entertainment, education, ... outdoor Internet access intelligent travel guide with up-to-date
location dependent information ad-hoc networks for
multi user games
UMTS, WLAN,DAB, GSM, TETRA, ...
Personal Travel Assistant,DAB, PDA, laptop, GSM, UMTS, WLAN, Bluetooth, ...
Location dependent services
Location aware services what services, e.g., printer, fax, phone, server etc. exist in the local environment
Follow-on services automatic call-forwarding, transmission of the actual workspace to the current location
Information services „push“: e.g., current special offers in the supermarket „pull“: e.g., where is the Black Forrest Cherry Cake? Support services caches, intermediate results, state information etc. „follow“ the mobile device through the
fixed networkPrivacy
who should gain knowledge about the location
Mobile devices
Pager• receive only• tiny displays• simple text messages
PDA• simple graphical displays• character recognition• simplified WWW
Laptop• fully functional• standard applications
Mobile phones• voice, data• simple text displays
Palmtop• tiny keyboard• simple versions of standard applications
Effects of device portability
Power consumption limited computing power, low quality displays, small disks due to limited battery
capacity CPU: power consumption ~ CV2f
C: internal capacity, reduced by integration V: supply voltage, can be reduced to a certain limit f: clock frequency, can be reduced temporally
Loss of data higher probability, has to be included in advance into the design (e.g., defects, theft)
Limited user interfaces compromise between size of fingers and portability integration of character/voice recognition, abstract symbols
Limited memory limited value of mass memories with moving parts
flash-memory or as alternative
Wireless networks in comparison to fixed networks
Higher loss-rates due to interference emissions of, e.g., engines, lightning,Restrictive regulations of frequencies frequencies have to be coordinated, useful frequencies are almost all occupied Low
transmission rates regional currently, e.g., 9.6kbit/s with GSM Higher delays, higher jitter connection setup time with GSM in the second range, several hundred milliseconds for
other wireless systems ,Lower security, simpler active attacking radio interface accessible for everyone, base station can be simulated, thus attracting calls
from mobile phones ,Always shared medium secure access mechanisms important
Areas of research in mobile communication
Wireless Communication transmission quality (bandwidth, error rate, delay) modulation, coding, interference media access, regulations
Mobility location dependent services location transparency quality of service support (delay, jitter, security) ...
Portability power consumption limited computing power, sizes of display,Usability
So, Simple reference model used here
Influence of mobile communication to the layer model
Application layer service location new applications, multimedia adaptive applications
Transport layer
congestion and flow control
quality of service
Network layer
addressing, routing, device location
hand-over
Data link layer
authentication
media access
multiplexing
media access control
Physical layer
ApplicationTransportNetwork
Data LinkPhysical
Medium
Data LinkPhysical
ApplicationTransportNetwork
Data LinkPhysical
Data LinkPhysical
Network Network
Radio
encryption
modulation
interference
attenuation
frequency
Overlay Networks (computer network which is built on the top of another network)- the global goal
MOBILE RADIO COMMUNICATION Network
The first wire line telephone system was introduced in the year 1877. Mobile communication
regional
metropolitan area
campus-based
verticalhand-over
horizontalhand-over
integration of heterogeneous fixed andmobile networks with varyingtransmission characteristics
Systems as early as 1934 were based on Amplitude Modulation (AM) Schemes and only certain public organizations maintained such systems. With the Demand for newer and better mobile radio communication systems during the WorldWar II and the development of Frequency Modulation (FM) technique by Edwin Armstrong, the mobile radio communication systems began to witness many new Changes. Mobile telephone was introduced in the year 1946.
However, during its initial three and a half decades it found very less market penetration owing to high costs and numerous technological drawbacks. But with the development of the cellularconcept in the 1960s at the Bell Laboratories, mobile communications began to be a promising held of expanse which could serve wider populations. Initially, mobile communication was restricted to certain official users and the cellular concept was never even dreamt of being made commercially available. Moreover, even the growth in the cellular networks was very slow. However, with the development of newer and better technologies starting from the 1970s and with the mobile users now connected to the Public Switched Telephone Network (PSTN), there has been an astronomical growth in the cellular radio and the personal communication systems.
Advanced Mobile Phone System (AMPS) was the first U.S. cellular telephone system and it was deployed in 1983. Wireless services have since then been experiencing a 50% per year growth rate. The number of cellular telephone users grew from 25000 in 1984 to around 3 billion in the year 2007 and the demand rate is increasing day by day.
Present Day Mobile Communication
Since the time of wireless telegraphy, radio communication has been used extensively.Our society has been looking for acquiring mobility in communication since then.Initially the mobile communication was limited between one pair of users on single channel pair. The range of mobility was defined by the transmitter power, type of antenna used and the frequency of operation. With the increase in the number of users, accommodating them within the limited available frequency spectrum became a major problem. To resolve this problem, the concept of cellular communication was evolved. The present day cellular communication uses a basic unit called cell. Each cell consists of small hexagonal area with a base station located at the center of the cell which communicates with the user. To accommodate multiple users Time Division multiple Access (TDMA), Code Division Multiple Access (CDMA),Frequency Division Multiple Access (FDMA) and their hybrids are used..
Radio Transmission Techniques
Based on the type of channels being utilized, mobile radio transmission systems may be classified as the following three categories .
1.Simplex System: Simplex systems utilize simplex channels i.e., the communication is unidirectional. The first user can communicate with the second user. However, the second user cannot communicate with the first user.
2. Half Duplex System: Half duplex radio systems that use half duplex radio channels allow for non-simultaneous bidirectional communication. The first user can communicate with the second user but the second user can communicate to the first user only after the first user has finished his conversation.At a time, the user can only transmit or receive information.
3.0Full Duplex System: Full duplex systems allow two way simultaneous communications.Both the users can communicate to each other simultaneously.This can be done by providing two simultaneous but separate channels to boththe users. This is possible by one of the two following methods.
Frequency Division Duplexing (FDD): FDD supports two-way radiocommunication by using two distinct radio channels. One frequency channelis transmitted downstream from the BS to the MS (forward channel).
Time Division Duplexing (TDD): TDD uses a single frequency band to transmit signals in both the downstream and upstream directions.TDD operates by toggling transmission directions over a time interval. This toggling takes place very rapidly and is imperceptible to the user.
How a Mobile Call is Actually Made?
Operational ChannelsIn each cell, there are four types of channels that take active part during a mobile call. These are:
1. Forward Voice Channel (FVC): This channel is used for the voice transmission from the BS to the MS.
2. Reverse Voice Channel (RVC): This is used for the voice transmission from the MS to the BS.
3. Forward Control Channel (FCC): Control channels are generally used for controlling the activity of the call, i.e., they are used for setting up calls and to divert the call to unused voice channels.
4.Reverse Control Channel (RCC): This is used for the call control purpose from the MS to the BS. Control channels are usually monitored by mobiles.
Making a CallWhen a mobile is idle, i.e., it is not experiencing the process of a call, then it searches all the FCCs to determine the one with the highest signal strength. The mobile then monitors this particular FCC. However, when the signal strength falls below a particular threshold that is insu_cient for a call to take place, the mobile again searches all the FCCs for the one with the highest signal strength. For a particularcountry or continent, the control channels will be the same. So all mobiles in that country or continent will search among the same set of control channels. However,when a mobile moves to a different country or continent, then the control channels or that particular location will be different and hence the mobile will not work.Each mobile has a mobile identification number (MIN). When a user wants to make a call, he sends a call request to the MSC on the reverse control channel. He also sends the MIN of the person to whom the call has to be made. The MSC then sends this MIN to all the base stations. The base station transmits this MIN and all the mobiles within the coverage area of that base station receive the MIN and matchit with their own. If the MIN matches with a particular MS, that mobile sends an acknowledgment to the BS. The BS then informs the MSC that the mobile is within its coverage area. The MSC then instructs the base station to access specific unused voice channel pair. The base station then sends a message to the mobile to move to the particular channels and it also sends a signal to the mobile for ringing.
Future TrendsTremendous changes are occurring in the area of mobile radio communications, so much so that the mobile phone of yesterday is rapidly turning into a sophisticated mobile device capable of more applications than PCs were capable of only a few years ago. Rapid development of the Internet with its new services and applications has created fresh challenges for the further development of mobile communication systems. Further enhancements in modulation schemes will soon increase the Internetaccess rates on the mobile from current 1.8 Mbps to greater than 10 Mbps.Bluetooth is rapidly becoming a common feature in mobiles for local connections.The mobile communication has provided global connectivity to the people at a lower cost due to advances in the technology and also because of the growing competition among the service providers.
MOBILE WIRELESS COMMUNICATION Network
At the initial phase, mobile communication was restricted to certain official users and the cellular concept was never even dreamt of being made commercially available.
Moreover, even the growth in the cellular networks was very slow. However, with the development of newer and better technologies starting from the 1970s and with the mobile users now connected to the PSTN, there has been a remarkable growth in the cellular radio.
However, the spread of mobile communication was very fast in the 1990s when the government throughout the world provided radio spectrum licenses for Personal Communication Service (PCS) in 1.8 to 2 GHz frequency band. The wired world and the wireless world are converging. The Internet and mobile wireless is converging. The distinction between the wireless, wire line and the Internet service providers is beginning to shape. And the glue certainly is "mobile wireless".
Mobile wireless has exploded in popularity because of the fact that it. The success of mobile communications lies in the ability to provide instant connectivity anytime and anywhere and the ability to provide high-speed data services to the mobile user. The quality and speeds available in the mobile environment must match the fixed networks if the convergence of the mobile wireless and fixed communication networks is to happen in the real sense. So, the challenges for the mobile networks lie in providing a very large footprint of mobile services (to make the movement from one network to another as transparent to the user as possible) and the availability of high speed reliable data services along with high quality voice. A range of successful mobile technologies exists today in various parts of the world and every technology must evolve to fulfill all these requirements. simplifies and revolutionizes communication.
Recent developments and initiatives include:
GSM Association together with the Universal Wireless Communications Consortium (UWCC), which represents the interests of the TDMA community, are working towards inter-standard roaming between GSM and TDMA (ANSI-136) networks.
The majority of European GSM operators plan to implement general packet radio system (GPRS) technology as their network evolution path to third-generation.
GSM cordless telephony system to provide a small home base station to work with a standard GSM mobile phone in similar mode to a cordless phone. The base station would be connected to the PSTN.
Number portability will allow customers to retain their mobile numbers when they change operators or service providers. Location services to standardize the methods for determining a GSM subscriber's physical location.
Mobile Wireless Communications Tomorrow
The drive for 3G is the need for higher capacities and higher data rates. Whereas higher capacities can basically be obtained by having a greater chunk of spectrum or by using new evolved air interfaces, the data requirements can be served to a certain extent by overlaying 2.5G technologies on the existing networks. In many cases it is possible to provide higher speed packet data by adding few network elements and a software upgrade.
A Look At GPRS, HCSD, and EDGE
Technologies like GPRS (General Packet Radio Service), High Speed Circuit Switched Data (HSCSD) and EDGE fulfill the requirements for packet data service and increased data rates in the existing
GSM/TDMA networks. I'll talk about EDGE separately under the section "Migration To 3G". GPRS is actually an overlay over the existing GSM network, providing packet data sevices using the same air interface by the addition of two new network elements, the SGSN and GGSN, and a software upgrade. Although GPRS was basically designed for GSM networks, the IS-136 Time Division Multiple Access (TDMA) standard, popular in North and South America, will also support GPRS. This follows an agreement to follow the same evolution path towards third generation mobile phone networks concluded in early 1999 by the industry associations that support these two network types.
The General Packet Radio Service (GPRS)
The General Packet Radio Service (GPRS) is a wireless service that is designed to provide a foundation for a number of data services based on packet transmission. Customers will only be charged for the communication resources they use. The operator's most valuable resource, the radio spectrum, can be leveraged over multiple users simultaneously because it can support many more data users. Additionally more than one time slots can be used by a user to get higher data rates.
3G MOBILE COMMUNICATOIN Network
What is 2G ?
Second Generation (2G) wireless cellular mobile services was a step ahead of First Generation( 1G)
services by providing the facility of short message service(SMS) unlike 1G that had its prime focus on
verbal communication. A typical 2G G.S.M network service ranges from 800/900MHz or 1800/1900
spectrum. The bandwidth of 2G is 30-200 KHz.
Analysis of 1G and 2G services
In 1G, Narrow band analogue wireless network is used, with this we can have the voice calls and can send
text messages. These services are provided with circuit switching. Today’s the usual call starts from the
beginning pulse to rate to the final rate. Then in case of 2G Narrow Band Wireless Digital Network is
used. It brings more clarity to the conversation and both these circuit-switching model.
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Both the 1G and 2G deals with voice calls and has to utilize the maximum bandwidth as well as a limited
till sending messages i.e. SMS. The latest technologies such as GPRS, is not available in these
generations. But the greatest disadvantage as concerned to 1G is that with this we could contact with in
the premises of that particular nation, where as in case of 2G the roaming facility a semi-global facility is
available.
2.5 Generation
In between 2G and 3G there is another generation called 2.5G. Firstly, this mid generation was introduced
mainly for involving latest bandwidth technology with addition to the existing 2G generation. To be frank
but this had not brought out any new evolution and so had not clicked to as much to that extend.
What is 3G Generation
But to overcome the limitations of 2G and 2.5G the 3G had been introduced. In this 3G Wide Brand
Wireless Network is used with which the clarity increases and gives the perfection as like that of a real
conversation. The data are sent through the technology called Packet Switching .Voice calls are
interpreted through Circuit Switching. It is a highly sophisticated form of communication that has come
up in the last decade.
In addition to verbal communication it includes data services, access to television/video, categorizing it
into triple play service. 3G operates at a range of 2100MHz and has a bandwidth of 15-20MHz. High
speed internet service, video chatting are the assets of 3G.
How is 2G different from 3G?
In comparison to 2G customers will have to pay a relatively high license fee for 3G.
The network construction and maintenance for 3G is much expensive than 2G.
From the point of view of customers, expenditure will be excessively high if they make access to
various facets of 3G.
3G and 4G Features
Main 3G Services
With the help of 3G, we can access many new services too. One such service is the GLOBAL
ROAMING. Another thing to be noted in case of 3G is that Wide Band Voice Channel that is by this the
world has been contracted to a little village because a person can contact with other person located in any
part of the world and can even send messages too. Then the point to be noted is that 3G gives clarity of
voice as well can talk without any disturbance. Not only these but also have entertainments such as Fast
Communication, Internet, Mobile T.V, Video Conferencing, Video Calls, Multi Media Messaging Service
(MMS), 3D gaming, Multi-Gaming etc are also available with 3G phones.
Main 4G Feature
When It is still to estimate as to how many number of people have moved on from 2G to 3G , technology
has come up with the latest of its type namely 4G.A successor of 2G and 3G, 4G promises a downloading
speed of 100Mbps and is yet to shower its wonders on. then with the case of Fourth Generation that is 4G
in addition to that of the services of 3G some additional features such as Multi-Media Newspapers, also to
watch T.V programs with the clarity as to that of an ordinary T.V. In addition, we can send Data much
faster that that of the previous generations.
What is the reason for delay in implementing 3G and 4G Mobile services?
It is very sad to say that the 3G services had only reached with in some towns of china, so that it may take
time to reach to Other countries.
Another major defect of this is
that Wide Band Frequency
Spectrum, which is needed for
3G, is lacking. Another reason for
this is that it a cost bearing item
especially for sending data. So for
us it is a higher one which could
be used only by upper classes. If
it should be accepted among all
customers, firstly it should be
availed at a lower rate, for which
the rate of spectrum should be declined.
Present Status of these technologies in Asian Countries
Now we are in the midst of 4G. In China, the 3G service came into existence only by last February. Therefore, that it may take time for exposing to other states. But we should also realize many other countries such as the Asian countries were using these services since last decade. Due to these reasons, we can hope that the 4G may enter within a few years. The 3G (Third Generation) had also reached India recently.
Body-to-body networks could be the future of mobile communication Network
A new system being developed by researchers at Queen’s University Belfast could turn this weakness into strength by allowing members of the public carrying wearable sensors to form the backbone of new mobile Internet networks.The system being investigated by engineers from Queen’s Institute of
Electronics, Communications and Information Technology (ECIT) is similar to the mesh network “bat phones” being developed by researchers in Australia and the new device-to-device wireless technology developed by the Wi-Fi Alliance. It would create new ultra high bandwidth mobile Internet infrastructures through the use of small sensors carried by members of the public in devices such as next generation smart phones. These sensors could communicate with each other, transmitting data to create potentially vast body-to-body networks (BBNs) to provide ‘anytime, anywhere’ mobile Internet connectivity.
RECENT R & D IN MOBILE COMMUNICATION NETWORK is in which country?
In America, Cisco is playing great job on research & development in MOBILE COMMUNICATION NETWORK . Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States that designs and sells consumer electronics, networking, voice, and communications technology and services.
