NOTES MAGIC: Mobile and wireless computing .

MOBILE COMPUTING

Mobile computing is human–computer interaction by which a computer is expected to be transported during normal usage.

Mobile computing involves mobile communication, mobile hardware, and mobile software.

1. Mobile data communication

Communication issues include ad hoc and infrastructure networks as well as communication properties, protocols, data formats and concrete technologies.

Wireless data connections used in mobile computing take three general forms so.

Cellular data service uses technologies such as GSM, CDMA or GPRS, 3G networks such as W-CDMA,EDGE or CDMA2000. and more recently 4G networks such as LTE, LTE-Advanced. These networks are usually available within range of commercial cell towers.

Wi-Fi connections offer higher performance, may be either on a private business network or accessed through public hotspots, and have a typical range of 100 feet indoors and up to 1000 feet outdoors.

Satellite Internet access covers areas where cellular and Wi-Fi are not available and may be set up anywhere the user has a line of sight to the satellite's location, which for satellites in geostationary orbit means having an unobstructed view of the southern sky.

Some enterprise deployments combine networks from multiple cellular networks or use a mix of cellular, Wi-Fi and satellite.

When using a mix of networks, a mobile virtual private network (mobile VPN) not only handles the security concerns, but also performs the multiple network logins automatically and keeps the application connections alive to prevent crashes or data loss during network transitions or coverage loss.

2. Mobile hardware

Mobile hardware includes mobile devices or device components that receive or access the service of mobility.
They would range from Portable laptops, Smartphones, Tablet Pc's, Personal Digital Assistants.
These devices will have receptor medium that are capable of sensing and receiving signals.
These devices are configured to operate in full- duplex, whereby they are capable of sending and receiving signals at the same time.
They don't have to wait until one device has finished communicating for the other device to initiate communications.
These devices use an existing and established network to operate on. In most cases, it would be a wireless network.

3. Mobile software

Mobile software deals with the characteristics and requirements of mobile applications.
Mobile software is the actual program that run on the mobile hardware.
It deals with the characteristics and requirements of mobile applications.
This is the engine of that mobile device.
In other terms, it is the operating system of that appliance.
It's the essential component that makes the mobile device operate.

DEVICES

Some of the most common forms of mobile computing devices are as follows.

Portable computers, compacted lightweight units including a full character set keyboard and primarily intended as hosts for software that may be parametrized, as laptops, notebooks, notepads, etc.
Mobile phones including a restricted key set primarily intended but not restricted to for vocal communications, as cell phones, smart phones, phonepads, etc.
Smart cards that can run multiple applications but typically payment, travel and secure area access
Wearable computers, mostly limited to functional keys and primarily intended as incorporation of software agents, as watches, wristbands, necklaces, keyless implants, etc.

The existence of these classes is expected to be long lasting, and complementary in personal usage, none replacing one the other in all features of convenience.

Other types of mobile computers have been introduced since the 1990s including the:

Portable computer (discontinued)
Personal digital assistant/Enterprise digital assistant (discontinued)
Ultra-Mobile PC (discontinued)
Laptop
Smartphone
Robots
Tablet computer
Wearable computer
Carputer
Application-specific computer

ADVANTAGES OF MOBILE COMPUTING

1. Location flexibility

This has enabled user to work from anywhere as long as there is a connection established.
A user can work without being in a fixed position. Their mobility ensures that they are able to carry out numerous tasks at the same time perform their stated jobs.

2. Saves Time

The time consumed or wasted by travelling from different locations or to the office and back, have been slashed.
One can now access all the important documents and files over a secure channel or portal and work as if they were on their computer.
It has enhanced telecommuting in many companies.
This also reduces unnecessary expenses that might be incurred.

3. Enhanced Productivity

Productive nature has been boosted by the fact that a worker can simply work efficiently and effectively from which ever location they see comfortable and suitable.
Users are able to work with comfortable environments.

4. Ease of research

Research has been made easier, since users will go to the field and search for facts and feed them back to the system.
It has also made it easier for field officer and researchers to collect and feed data from wherever they without making unnecessary trip to and from the office to the field.

5. Entertainment

Video and audio recordings can now be streamed on the go using mobile computing. It's easy to access a wide variety of movies, educational and informative material.
With the improvement and availability of high speed data connections at considerable costs, one is able to get all the entertainment they want as they browser the internet for streamed data.
One can be able to watch news, movies, and documentaries among other entertainment offers over the internet. This was not such before mobile computing dawned on the computing world.

6. Streamlining of Business Processes

Business processes are now easily available through secured connections. Basing on the factor of security, adequate measures have been put in place to ensure authentication and authorization of the user accessing those services.
Some business functions can be run over secure links and also the sharing of information between business partners. Also it's worth noting that lengthy travelling has been reduced, since there is the use of voice and video conferencing.
Meetings, seminars and other informative services can be conducted using the video and voice conferencing. This cuts down on travel time and expenditure.

LIMITATIONS

Range and Bandwidth: Mobile Internet access is generally slower than direct cable connections, using technologies such as GPRS and EDGE, and more recently HSDPA and HSUPA 3Gand 4G networks and also upcoming 5G network. These networks are usually available within range of commercial cell phone towers. High speed network 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.(While this may seem obvious, there is considerable discussion about whether banning mobile device use while driving reduces accidents or not.) 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.

Security issues involved in mobile

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.

WIRELESS COMPUTING / NETWORK

A wireless network is any type of computer network that uses wireless data connections for connecting network nodes.

Wireless networking is a method by which homes, telecommunications networks and enterprise (business) installations avoid the costly process of introducing cables into a building, or as a connection between various equipment locations.

Wireless telecommunications networks are generally implemented and administered using radio communication. This implementation takes place at the physical level (layer) of the OSI model network structure.

Examples of wireless networks include cell phone networks, Wi-Fi local networks and terrestrial microwave networks.

TYPES

1. Wireless PAN

Wireless personal area networks (WPANs) interconnect devices within a relatively small area, that is generally within a person's reach.
Example, both Bluetooth radio and invisible in frared light provides a WPAN for interconnecting a headset to a laptop. ZigBee also supports WPAN applications.
Wi-Fi PANs are becoming commonplace (2010) as equipment designers start to integrate Wi-Fi into a variety of consumer electronic devices. Intel "My WiFi" and Windows 7 "virtual Wi-Fi" capabilities have made Wi-Fi PANs simpler and easier to set up and configure.

2. Wireless LAN

A wireless local area network (WLAN) links two or more devices over a short distance using a wireless distribution method, usually providing a connection through an access point for Internet access.
The use of spread-spectrum or OFDM technologies may allow users to move around within a local coverage area, and still remain connected to the network.
Products using the IEEE 802.11 WLAN standards are marketed under the Wi-Fi brand name. Fixed wireless technology implements point-to-point links between computers or networks at two distant locations, often using dedicated microwave or modulated laser light beams over line of sight paths.
It is often used in cities to connect networks in two or more buildings without installing a wired link.

3. Wireless mesh network

A wireless mesh network is a wireless network made up of radio nodes organized in a mesh topology.
Each node forwards messages on behalf of the other nodes. Mesh networks can "self heal", automatically re-routing around a node that has lost power.

4. Wireless MAN

Wireless metropolitan area networks are a type of wireless network that connects several wireless LANs.
WiMAX is a type of Wireless MAN and is described by the IEEE 802.16 standard.

5. Wireless WAN

Wireless wide area networks are wireless networks that typically cover large areas, such as between neighboring towns and cities, or city and suburb.
These networks can be used to connect branch offices of business or as a public internet access system.
The wireless connections between access points are usually point to point microwave links using parabolic disheson the 2.4 GHz band, rather than omnidirectional antennas used with smaller networks.
A typical system contains base station gateways, access points and wireless bridging relays.
Other configurations are mesh systems where each access point acts as a relay also. When combined with renewable energy systems such as photo-voltaic solar panels or wind systems they can be stand alone systems.

USE : WIRELESS COMPUTING

Usage include cellular phones which are part of everyday wireless networks, allowing easy personal communications.
Inter-continental network systems, use radio satellites to communicate across the world.
Emergency services such as the police utilize wireless network computing to communicate effectively as well. Individuals and businesses use wireless networks to send and share data rapidly, whether it be in a small office building or across the world.

PROPERTIES / CHARACCTERISTICS : WIRELESS COMPUTING

1. General

In a general sense, wireless networks offer a vast variety of uses by both business and home users.

"Now, the industry accepts a handful of different wireless technologies. Each wireless technology is defined by a standard that describes unique functions at both the Physical and the Data Link layers of the OSI model. These standards differ in their specified signaling methods, geographic ranges, and frequency usages, among other things. Such differences can make certain technologies better suited to home networks and others better suited to network larger organizations."

2. Performance

Each standard varies in geographical range, thus making one standard more ideal than the next depending on what it is one is trying to accomplish with a wireless network.
The performance of wireless network computing satisfies a variety of applications such as voice and video.
The use of this technology also gives room for expansions, such as from 2G to 3G and, most recently, 4G technology, which stands for fourth generation of cell phone mobile communications standards.
As wireless networking has become commonplace, sophistication increases through configuration of network hardware and software, and greater capacity to send and receive larger amounts of data, faster, is achieved.

3. Space

Space is another characteristic of wireless networking. Wireless networks offer many advantages when it comes to difficult-to-wire areas trying to communicate such as across a street or river, a warehouse on the other side of the premise or buildings that are physically separated but operate as one.
Wireless networks allow for users to designate a certain space which the network will be able to communicate with other devices through that network.
Space is also created in homes as a result of eliminating clutters of wiring.
This technology allows for an alternative to installing physical network mediums such as TPs, coaxes, or fiber-optics, which can also be expensive.

4. Home

For homeowners, wireless technology is an effective option compared to ethernet for sharing printers, scanners, and high speed internet connections.
WLANs help save the cost of installation of cable mediums, save time from physical installation, and also creates mobility for devices connected to the network.
Wireless networks are simple and require as few as one single wireless access point connected directly to the Internet via a router.

WIRELESS NETWORK ELEMENTS

The telecommunications network at the physical layer also consists of many interconnected wireline Network Elements (NEs). These NEs can be stand-alone systems or products that are either supplied by a single manufacturer, or are assembled by the service provider (user) or system integrator with parts from several different manufacturers.Wireless NEs are products and devices used by a wireless carrier to provide support for the backhaul network as well as a Mobile Switching Center (MSC).
Reliable wireless service depends on the network elements at the physical layer to be protected against all operational environments and applications.
What are especially important are the NEs that are located on the cell tower to the Base Station (BS) cabinet.
The attachment hardware and the positioning of the antenna and associated closures/cables are required to have adequate strength, robustness, corrosion resistance, and rain/solar resistance for expected wind, storm, ice, and other weather conditions.
Requirements for individual components, such as hardware, cables, connectors, and closures, shall take into consideration the structure to which they are attached.

DIFFICULTIES / DISADVANTAGES OF WIRELESS NETWORKS

1. Interference: Compared to wired systems, wireless networks are frequently subject to electromagnetic interference. This can be caused by other networks or other types of equipment that generate radio waves that are within, or close, to the radio bands used for communication. Interference can degrade the signal or cause the system to fail.

2. Absorption and reflection: Some materials cause absorption of electromagnetic waves, preventing it from reaching the receiver, in other cases, particularly with metallic or conductive materials reflection occurs. This can cause dead zones where no reception is available. Aluminium foiled thermal isolation in modern homes can easily reduce indoor mobile signals by 10 dB frequently leading to complaints about bad reception of long distance rural cell signals.

3. Multipath fading: In multipath fading two or more different routes taken by the signal, due to reflections, can cause the signal to cancel out at certain locations, and to be stronger in other places (upfade).

4. Hidden node problem: The hidden node problem occurs in some types of network when a node is visible from a wireless access point (AP), but not from other nodes communicating with that AP. This leads to difficulties in media access control.

5. Shared resource problem: The wireless spectrum is a limited resource and shared by all nodes in the range of its transmitters. Bandwidth allocation becomes complex with multiple participating users. Often users are not aware that advertised numbers (e.g., for IEEE 802.11 equipment or LTE networks) are not their capacity, but shared with all other users and thus the individual user rate is far lower. With increasing demand, the capacity crunch is more and more likely to happen. User-in-the-loop (UIL) may be an alternative solution to ever upgrading to newer technologies forover-provisioning.

NETWORK

Cellular wireless networks generally have good capacity, due to their use of directional aerials, and their ability to reuse radio channels in non-adjacent cells.
Additionally, cells can be made very small using low power transmitters, and this fact is used in cities to give network capacity that scales linearly with population density.
The total network bandwidth depends on how dispersive the medium is (more dispersive medium generally has better total bandwidth because it minimises interference), how many frequencies are available, how noisy those frequencies are, how many aerials are used and whether directional antenna are in use, whether nodes employ power control and so on.

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SPECIALIZATION :

Mobile and wireless computing .