MOBILE COMPUTING                                                              

ABSTRACT:-

            

      Technology has developed rapidly over the last twenty years. This development in technology resulted in the development of communication. For example, Internet, email, Voicemail, etc. This development has still not given the user the freedom to access data anywhere or anytime he wants because of the limitations like the change in location resulted in either routing problems or connection breaks.

            The advent of MOBILE COMPUTING has given birth to hopes of overcoming the above limitations. These mobile networks have facilitated communication anywhere in the world at any time. The word MOBILE itself illustrated what it does. These mobile networks provide communication even when the source and destination are constantly changing their location.

                               

 INTRODUCTION:-

 

           Don Ring of Bell Labs, USA in 1947, invented the cellular concept. The first commercial mobile communications were in the form of radio paging networks. Advanced Mobile Phone System (AMPS) is a major cellular networks established in America using analog cellular technology. Total Access Communication System (TACS) is a major system use in Europe. Recently a number of digital communications are also introduced. The present trend is to cover communications anywhere in the world and at any time of the day. Cellular concept based on the concept of network of cells, which covers a large geographical area to communicate over the world.

  Mobile Computing is a program that allows user to access wireless network. This is done by using Radio Frequency (RF) technology to transmit data through the air without wired cabling. Mobile Computing provides all the same features and benefits of the existing campus network, but without the limitations of being tethered to a cable.

The goals of this service are to provide expanded wireless coverage for the campus, provide access to wireless monitor usage and solicit feedback in order to determine scope and scale of future expansion.

 IMPORTANCE OF MOBILE COMPUTERS:-

Mobile Computing is becoming increasingly important due to the rise in the number of portable computers and the desire to have continuous network connectivity to the Internet irrespective of the physical location of the node. The Internet infrastructure is built on top of a collection of protocols, called the TCP/IP protocol suite. The Mobile Internet Protocol (Mobile IP) is an extension to the Internet Protocol proposed by the Internet Engineering Task Force (IETF) . It enables mobile computers to stay connected to the Internet regardless of their location and without changing their IP address. More precisely, Mobile IP is a standard protocol that builds on the Internet Protocol by making mobility transparent to applications and higher level protocols like TCP. 

     

 

 

 

 

HOW MOBILE IP WORKS:-

IP routes packets from a source endpoint to a destination by allowing routers to forward packets from incoming network interfaces to outbound interfaces according to routing tables. The routing tables typically maintain the next-hop (outbound interface) information for each destination IP address, according to the number of networks to which that IP address is connected. The network number is derived from the IP address by masking off some of the low-order bits. Thus, the IP address typically carries with it information that specifies the IP node's point of attachment.

To maintain existing transport-layer connections as the mobile node moves from place to place, it must keep its IP address the same. In TCP (which accounts for the overwhelming majority of Internet connections), connections are indexed by a quadruplet that contains the IP addresses and port numbers of both connection endpoints. Changing any of these four numbers will cause the connection to be disrupted and lost. On the other hand, correct delivery of packets to the mobile node's current point of attachment depends on the network number contained within the mobile node's IP address, which changes at new points of attachment. To change the routing requires a new IP address associated with the new point of attachment.

Mobile IP has been designed to solve this problem by allowing the mobile node to use two IP addresses (see the sidebar "Mobile Networking Terminology" for definitions of italicized terms). In Mobile IP, the home address is static and is used, for instance, to identify TCP connections. The care-of addresses changes at each new point of attachment and can be thought of as the mobile node's topologically significant address; it indicates the network number and thus identifies the mobile node's point of attachment with respect to the network topology. The home address makes it appear that the mobile node is continually able to receive data on its home network, where Mobile IP requires the existence of a network node known as the home agent. Whenever the mobile node is not attached to its home network (and is therefore attached to what is termed a foreign network), the home agent gets all the packets destined for the mobile node and arranges to deliver them to the mobile node's current point of attachment.

Whenever the mobile node moves, it registers its new care-of address with its home agent. To get a packet to a mobile node from its home network, the home agent delivers the packet from the home network to the care-of address. The further delivery requires that the packet be modified so that the care-of address appears as the destination IP address. This modification can be understood as a packet transformation or, more specifically, a redirection. When the packet arrives at the care-of address, the reverse transformation is applied so that the packet once again appears to have the mobile node's home address as the destination IP address. When the packet arrives at the mobile node, addressed to the home address, it will be processed properly by TCP or whatever higher level protocol logically receives it from the mobile node's IP (that is, layer 3) processing layer.

DIFFERENT TYPES OF MOBILE SYSTEMS:-

                In many ways mobile computing has several characteristics of distributed systems. Here we explain the different types of distributed systems ranging from the traditional type to nomadic, ad-hoc and finally ubiquitous ones.

TRADITIONAL DISTRIBUTED SYSTEMS

            Traditional distributed systems consists of a collection of fixed hosts that are themselves attached to a network- if hosts are disconnected from the network this is considered to be abnormal whereas in a mobile system this is quite the norm. These hosts are fixed. The bandwidth in traditional systems is very high too.

            The execution context is said to be static as opposed to a dynamic context whereby host joined and leave the network frequently. in a traditional system ,location rarely changes as well and hosts are much less likely to be added or deleted from the network

   Traditional distributed systems also need to guarantee non-functional requirements such as scalability, openness, heterogeneity, fault tolerance and finally resource sharing.

NOMADIC DISTRIBUTED SYSTEM

This kind of system is composed of a set of mobile devices and a core infrastructure with fixed and wired nodes. Mobile devices move from location to location while maintaining a connection to the fixed network. There are problems that arise from such shifts in location. The mobile host has a home IP address and thus any packets sent to mobile host will be delivered to the home network and not the foreign network where the mobile host is currently located. Such problem can be solved by forwarding packets to the foreign network with the help of mobile IP.

            These systems are susceptible to the uncertainty of location, a repeated lack of connections and the migration into different physical and logical environments while operating. However, compared to ad-hoc networks, nomadic systems still have comparatively reliable connections and services since most of these are actually supported by the fixed infrastructure of the network.

AD-HOC MOBILE DISTRIBUTED SYSTEM

Ad-hoc distributed systems are possibly the only type of network that comes close to mobile networks in the sense that every node is literally mobile.  It is these networks 0that are very much seen as the systems of the future, whereby hosts are connected to the network through high-variable quality links) e/g/ from GPS to broadband connection) and executed in an extremely dynamic environment

Ad-hoc systems do not have any fixed infrastructure which differs them both from traditional and nomadic distributed systems.  In fact, ad-hoc networks may come together as needed, not necessarily with any assistance from the existing (e.g. Internet) infrastructure.  When nodes are detached from the fixed/mobile network they may evolve independently and groups of hosts opportunistically from “clusters” of mini-networks.  The speed and ease of deployment make ad-hoc networks highly desirable.

THEORY IN MOBILE COMPUTERS:-

The trends of two fields related to mobile computing are

* MODELS

            Models permit the precise description of existing languages and system semantics.  In fact, they enable the formal reasoning about the correctness of such semantics.  Models are very much used to emphasize parallels and distinctions among various forms of mobility (logical and physical) and are concerned with the formulation of appropriate abstractions useful in specification and evaluation of such mobile systems

Models are mainly concerned with the characteristics of mobile units such as the unit of mobility (who is allowed to move), its location (where a mobile unit is positioned in space) and its context (determined by the current location of mobile units).  There are many existing models are many more are still in research.

·         Random mobility models(s)

·         Markovian model

·         Exponential Correlated Random Model

·         Nomadic Community Model.

*ALGORITHMS

       The current algorithms applied reflect the assumptions that are made about the underlying system.  Unfortunately, many of these assumptions are not suited for current algorithms for mobile systems.  Mobile algorithms are obliged to treat in much detail space and coordination of mobile systems.  In particular, algorithms have to carefully take into consideration location changes, the frequency of disconnection, power limitations and the dynamic changes in the connectivity pattern of mobile systems.  This field of theory is in fact spread among a vast spectrum of research due to the large diversity of mobile systems.

 

APPLICATIONS:-

   

The application areas of mobile technology include

• Consumer Goods
• Delivery and Route Sales
• Government
• Healthcare
• Market Research
• Pharmaceuticals
• Transportation and
• Utilities

 BENEFITS:-

         The benefits of automating data collection applications with mobile computing are the reduction of hard and soft costs, enhancement of revenue potential, and a distinct competitive advantage through:

• improving the data collection process
• improving data accuracy
• facilitating collection of more useful information
• eliminating redundant data entry
• improving information flow
• providing access to previously unavailable information

• Reduced radio congestion. 
• Improved supervision and resource management. 
• Less time in data transformation.   

                             

LIMITATIONS:-

           Range & Bandwidth: Mobile Internet access is generally slower than direct cable connections, using technologies such as GPRS and EDGE, and more recently HSDPA and HSUPA 3G and 4G networks. These networks are usually available within range of commercial cell phone towers. Higher speed wireless LANs are inexpensive but have very limited range.

• Security standards: When working mobile, one is dependent on public networks, requiring careful use of VPN. Security is a major concern while concerning the mobile computing standards on the fleet. One can easily attack the VPN through a huge number of networks interconnected through the line.
• Power consumption: When a power outlet or portable generator is not available, mobile computers must rely entirely on battery power. Combined with the compact size of many mobile devices, this often means unusually expensive batteries must be used to obtain the necessary battery life.
• Transmission interferences: Weather, terrain, and the range from the nearest signal point can all interfere with signal reception. Reception in tunnels, some buildings, and rural areas is often poor.
• Potential health hazards: People who use mobile devices while driving are often distracted from driving and are thus assumed more likely to be involved in traffic accidents.^[3] (While this may seem obvious, there is considerable discussion about whether banning mobile device use while driving reduces accidents or not.^[4][5]) Cell phones may interfere with sensitive medical devices. Questions concerning mobile phone radiation and health have been raised.
• Human interface with device: Screens and keyboards tend to be small, which may make them hard to use. Alternate input methods such as speech or handwriting recognition require training.

In-vehicle computing and fleet computing:-

Many commercial and government field forces deploy a ruggedized portable computer with their fleet of vehicles. This requires the units to be anchored to the vehicle for driver safety, device security, and ergonomics. Rugged computers are rated for severe vibration associated with large service vehicles and off-road driving and the harsh environmental conditions of constant professional use such as in emergency medical services, fire, and public safety.

 Typical fan-based cooling has stated limits of 95F-100F of ambient temperature, and temperatures below freezing require localized heaters to bring Several specialized manufacturers such as First Mobile Technologies, National Products Inc (Ram Mounts), Gamber Johnson and LedCo build mounts for vehicle mounting of computer equipment for a wide range of vehicles. The mounts are built to withstand the harsh conditions and maintain ergonomics.

Specialized installation companies design the mount design, assembling the parts, and installing them in a safe and consistent manner away from airbags, vehicle HVAC controls, and driver controls. Frequently installations will include a WWAN modem, power conditioning equipment, transceiver antennae mounted external to the vehicle, and WWAN/WLAN/GPS/etc.

 

 

SECURITY ISSUES:-

Mobile security or mobile phone security has become increasingly important in mobile computing. It is of particular concern as it relates to the security of personal information now stored on the smartphone.

More and more users and businesses use smartphones as communication tools but also as a means of planning and organizing their work and private life. Within companies, these technologies are causing profound changes in the organization of information systems and therefore they have become the source of new risks. Indeed, smartphones collect and compile an increasing amount of sensitive information to which access must be controlled to protect the privacy of the user and the intellectual property of the company.

All smartphones, as computers, are preferred targets of attacks. These attacks exploit weaknesses related to smartphones that can come from means of communication like SMS, MMS, wifi networks, and GSM. There are also attacks that exploit software vulnerabilities from both the web browser and operating system. Finally, there are forms of malicious software that rely on the weak knowledge of average users.

Different security counter-measures are being developed and applied to smartphones, from security in different layers of software to the dissemination of information to end users. There are good practices to be observed at all levels, from design to use, through the development of operating systems, software layers, and downloadable apps.

CONCLUSION:

This paper discusses every aspect for designing the mobile device in detail and I would like to draw attention of these issues while designing a mobile device or the device that going to be part of mobile computing domain.

At this stage we are facing different types of problems and threats to the mobile industry, the two major aspects are the security and the usability issue.