Next IT Information

Mobile WiMAX Technology

2009-11-03T00:10:00.000-08:00

Mobile WiMAX¹ is the next revolution in wireless technology that will enable pervasive, high-speed connectivity to meet the ever-increasing demand for broadband Internet on the go. Delivering the next leap in the mobile network evolution with fourth generation (4G) wireless, WiMAX will drive a wide array of devices well beyond what's available today, including notebooks, phones, consumer electronic devices, Mobile Internet Devices (MIDs) and more.
The only network optimized specifically for mobile broadband Internet, WiMAX is based on a set of global standards covering fixed, portable, and mobile deployments on an open network that will help drive and leverage the openness of the Internet, as opposed to prior generation's, closed systems, such as 3G networks.

The low-cost, all-IP network architecture and backwards compatibility with existing 2G and 3G cellular network deployments makes WiMAX easier and more cost-effective to deploy and operate than current mobile wireless data solutions. As a result, it has already garnered broad support from leading operators—both wired line and wireless—and device manufacturers around the world.
WiMAX provides two to three times the performance of 3G solutions today, with the ability to scale to ten times the performance in the future.² As a driving force in collaboration with industry leaders, Intel is working towards further expansion and support of WiMAX through technology advancements such as Intel® WiMAX/WiFi Link 5050 Series, an integrated module solution for notebooks with advanced MIMO antenna technology. Notebooks with Intel® Centrino® 2 processor technology will have Intel® WiMAX/WiFi Link 5050 Series as an available option in the latter half of 2008.

Source : INTEL

What Is Wimax

2009-11-02T23:57:00.000-08:00

WiMax is meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes, from point-to-multipoint links to portable and fully mobile internet access. The technology provides up to 10 Mbit/s broadband speed without the need for cables.
The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access). The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL"
The terms "WiMAX", "mobile WiMAX", "802.16d" and "802.16e" are frequently used incorrectly.[3] Correct definitions are the following:
802.16-2004 is often called 802.16d, since that was the working party that developed the standard. It is also frequently referred to as "fixed WiMAX" since it has no support for mobility.
802.16e-2005 is an amendment to 802.16-2004 and is often referred to in shortened form as 802.16e. It introduced support for mobility, among other things and is therefore also known as "mobile WiMAX".

Fixed WiMAX is similar in some respects to WLAN with an OFDM-based physical layer. Mobile WiMAX is based on an OFDMA physical layer. It uses both frequency division multiplex and time division multiplex. Groups of sub-carriers represent individual data streams. Uplink and Downlink communications can also utilize Time Division techniques. Because of increased signal complexity, high-speed measurements are required. This is absolutely necessary for complicated OFDM and MIMO (multiple-input multiple-output) signal structures.

What is Fiber Optic

2009-11-02T10:29:00.001-08:00

A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.

Fiber optics has several advantages over traditional metal communications lines:
Fiber optic cables have a much greater bandwidth than metal cables. This means that they can carry more data.
Fiber optic cables are less susceptible than metal cables to interference.
Fiber optic cables are much thinner and lighter than metal wires.
Data can be transmitted digitally (the natural form for computer data) rather than analogically.

The main disadvantage of fiber optics is that the cables are expensive to install. In addition, they are more fragile than wire and are difficult to splice.

Fiber optics is a particularly popular technology for local-area networks. In addition, telephone companies are steadily replacing traditional telephone lines with fiber optic cables. In the future, almost all communications will employ fiber optics.

The Fiber Optic Connector Identifier

2009-11-02T03:12:00.000-08:00

In the development of fiber optic technology over the last 30 years, many companies and individuals have invented the "better mousetrap" - a fiber optic connector that was lower loss, lower cost, easier to terminate or solved some other perceived problem. In all, about 100 fiber optic connectors have been introduced to the marketplace, but only a few represent the majority of the market. Here is a rundown of the connectors that have been the leaders of the industry.

The big silver connector at the bottom of the photo at the right is the Deutsch 1000, what was probably the first commercially successful fiber optic connector. It was really a "pin vise" holding a stripped fiber. The nose piece is spring loaded and was pushed back when the connector was inserted into a mating adapter. The fiber stuck out into a drop of index matching fluid on a plastic lens. This solution was state of the art in the late 70s, yielding about 3 dB loss. Many users remember it as the connector on the front panel of the original Tektronix OTDR.

Above it is the Biconic, the yellow body indicating a SM version. Developed by a team led by Jack Cook at Bell Labs in Murray Hill, NJ, the Biconic was molded from a glass-filled plastic that was almost as hard as ceramic. It started with the fiber being molded into the ferrule. This lasted until the company could get a 125 micron/5mil pin insert into the plastic mold, at which point the fiber was glued into the ferule with epoxy. When singlemode versions first appeared, the ferrules were ground to center the fiber core in the ferrule to reduce loss. Since it was not keyed and could rotate in the mating adapters, it had an airgap between the ferrules when mated, meaning loss was never less than 0.3 dB due to fresnel reflection. Usually MM Biconics had losses of 0.5-1 dB and SM 0.7 dB or higher.

The advent of the ceramic ferrule in the mid-80s in Japan changed the connector designs forever. The ceramic ferrule was hard and precise. Fibers were accurately located for alignment and ferrules could be allowed to touch. Adding in convex ferrules for PC (physical contact) between connectors reduced losses to levels below 0.3 dB for both MM and SM varieties.

In the late 90s, small form factor (SFF) connectors became popular, but only the LC (top) has been a runaway success, both in telcos and high bit rate LANs, SANs, etc.

Below are some more of the popular connectors over the years.
Color Codes:
Since the earliest days of fiber optics, orange, black or gray was multimode and yellow singlemode. However, the advent of metallic connectors like the FC and ST made color coding difficult, so colored boots were often used. The TIA 568 color code for connector bodies and/or boots is Beige for multimode fiber, Blue for singlemode fiber, and Green for APC (angled) connectors.

Use LAN (Local Area Network) and Fiber Optics Application

2009-11-01T04:37:00.000-08:00

Local Area Network (LAN) is a combined group of computers, or computer systems, connected to each other that allow shared program software or data bases. LAN systems are used by colleges, universities, office buildings, and industrial plants, for making use of optical fiber.

LAN in Colleges and Universities

With the technology of LAN and fiber optic applications, college students and professors can do their research from their rooms and offices without having to go to the library. It provides access to other campus colleges, enabling staff members to perform research with other college professors. It also enables students to take special courses from instructors at other colleges. College students in rural areas can now have quality-advanced curriculum without the high traveling expense.

Purchasing software programs for a network will save the college a tremendous amount of money and also allows for easier upgrading. Colleges can also have passwords on their programs for denying access to unauthorized users. Using passwords, they do not have to worry about programs being illegally copied.

Colleges or universities with a large number of students can add additional computers, scanners, and modems to the network for students to share.

LAN provides dollar savings for students by allowing them to e-mail their friends at home and on other campuses instead of having to pay for a long distance phone bill.

LAN and Office Buildings

More and more companies today are demanding that fiber optic applications be made available when considering an office building as a rental place for their businesses. Some companies will even pay more to rent a building or office with fiber optic applications because they feel it is very important for their business to have access to a fast communication network.

Companies that use fiber optic cables to set up their LAN do not have to worry with dangling and tangled cables, and their data is transmitted at an even higher quality and speed than with other network applications. With the fiber optic system, the company does not have to be concerned about a fire hazard because no electricity runs through the cables. Many very large office buildings use fiber optic lighting for their offices or for outdoor advertisements.

LAN and Industrial Plants

High-speed and high-quality communication links are needed in industrial plants. To monitor their processes online, industrial plants can use a fiber optic application to connect their control systems to their computer networks. A plant can also collect valuable information from other machines and plants that might help their plant’s machines run more smoothly and efficiently.

Optical fibers have many physical properties that make them an excellent choice for the harsh environmental conditions found in industrial plants such as electromagnetic interference (EMI), extreme temperatures, and even lightning strikes. Fiber optic cables are rugged, have a very large bandwidth, have long cable lengths, and are immune to electromagnetic interference (EMI).

By combining both LAN and fiber optic applications, colleges, universities, and businesses can obtain an almost endless stream of information on a daily basis. Companies can also use both of these to increase productivity while providing a convenient, safe environment for their employees and customers.

What for Fiber Optics Today

2009-11-01T04:32:00.000-08:00

First Use of Fiber Optics

One of the first uses of fiber optics was the telephone, and today, fiber optic technology has revolutionized long distance calls. It has also made wiretapping more difficult and helps to prevent electrical interference. Probably the biggest use today for fiber optics is the Internet, which is information that fiber optics cables send digitally.

Fiber Optics and the Military

Fiber optic technology is in high demand in the military today. The military has tested the cables rigorously and decided they were excellent to use in many of their applications. The fiber optic cables offer the military better performance, more bandwidth, and security for their signals - all at a lower cost. The cables are strong, lightweight, and can also be used outdoors in any type of harsh environment. These features make the fiber optic cables an excellent choice for use in the military’s retrieval and deployment applications.

Fiber optic missile launchers and radar systems are also used in the military. In many of their control systems, the military uses a single optical fiber to replace miles and pounds of copper wire.

Fiber Optics Used in our Transportation System

The fast-paced transportation system is becoming a fast growing market for the use of fiber optics with the increase in traffic and more demand for automated toll booths, traffic signals, and message signs that are changeable.

UAVs and Fiber Optics

A fairly new and fast growing application for fiber optics is Unmanned Aerial Vehicles (UAVs). With the ability to provide a fast and efficient way to transmit a large amount of data over long distances, fiber optics were utilized as the main communication conduit between the UAV and ground control.

Other Uses of Fiber Optics

Fiber optics are also used in applications where bright light needs to be shone on a target without a clear line-of-sight path. They are also used to route sunlight from a roof to other parts of the building.

Optical fiber illumination is used for decorative applications such as Christmas trees, signs, and art. Showcases displayed in boutiques use optical fibers for illumination of different angles with only one light source.

Special optical fibers are used for sensor applications in areas that involve oil-well monitoring and fire or leak detection.

The bandwidth offered by fiber optics enables cable television to transmit signals to their subscribers. This is very useful for the services cable companies offer. Other important fiber optic applications are used in research institutions, colleges and universities, aerospace, and chemical industries.

BRIEF OVER VIEW OF FIBER OPTIC CABLE ADVANTAGES OVER COPPER

2009-11-01T04:13:00.001-08:00

A fiber-optic system is similar to the copper wire system that fiber-optics is replacing. The difference is that fiber-optics use light pulses to transmit information down fiber lines instead of using electronic pulses to transmit information down copper lines. Looking at the components in a fiber-optic chain will give a better understanding of how the system works in conjunction with wire based systems.

At one end of the system is a transmitter. This is the place of origin for information coming on to fiber-optic lines. The transmitter accepts coded electronic pulse information coming from copper wire. It then processes and translates that information into equivalently coded light pulses. A light-emitting diode (LED) or an injection-laser diode (ILD) can be used for generating the light pulses. Using a lens, the light pulses are funneled into the fiber-optic medium where they travel down the cable. The light (near infrared) is most often 850nm for shorter distances and 1,300nm for longer distances on Multi-mode fiber and 1300nm for single-mode fiber and 1,500nm is used for for longer distances.

Think of a fiber cable in terms of very long cardboard roll (from the inside roll of paper towel) that is coated with a mirror on the inside.
If you shine a flashlight in one end you can see light come out at the far end - even if it's been bent around a corner.

Light pulses move easily down the fiber-optic line because of a principle known as total internal reflection. "This principle of total internal reflection states that when the angle of incidence exceeds a critical value, light cannot get out of the glass; instead, the light bounces back in. When this principle is applied to the construction of the fiber-optic strand, it is possible to transmit information down fiber lines in the form of light pulses. The core must a very clear and pure material for the light or in most cases near infrared light (850nm, 1300nm and 1500nm). The core can be Plastic (used for very short distances) but most are made from glass. Glass optical fibers are almost always made from pure silica, but some other

Mobile VOIP

2008-05-15T04:00:00.000-07:00

Mobile VoIP is an extension of mobility to a VoIP Voice over IP network.

There are several methodologies by which a mobile handset can be integrated into a VoIP network. One implementation turns the mobile device into a standard SIP client, which then uses a data network to send and receive SIP messaging, and to send and receive RTP for the voice path. This methodology of turning a mobile handset into a standard SIP client requires that the mobile handset support, at minimum, high speed IP communications. In this application, standard VoIP protocols (typically SIP) are used over any broadband IP-capable wireless network connection such as EVDO rev A (which is synchronously high speed — both high speed up and down), HSDPA, WiFi or WiMAX.

Another implementation of mobile integration uses a softswitch like gateway to bridge SIP and RTP into the mobile network's SS7 infrastructure. In this implementation, the mobile handset continues to operate as it always has (as a GSM or CDMA based device), but now it can be controlled by a SIP application server which can now provide advanced SIP based services to it. Several vendors offer this kind of capability today, including i2Telecom, Tango Networks, Outsmart, NewStep, BridgePort and BroadSoft.

Mobile VoIP will require a compromise between economy and mobility. For example, Voice over Wi-Fi offers potentially free service but is only available within the coverage area of a Wi-Fi Access Point. High speed services from mobile operators using EVDO rev A or HSDPA may have better audio quality and capabilities for metropolitan-wide coverage including fast handoffs among mobile base stations, yet it will cost more than the typical Wi-Fi-based VoIP service.

Mobile VoIP will become an important service in the coming years as device manufacturers exploit more powerful processors and less costly memory to meet user needs for ever-more 'power in their pocket'. Smartphones in mid-2006 are capable of sending and receiving email, browsing the web (albeit at low rates) and in some cases allowing a user to watch TV.

The challenge for the mobile operator industry is to deliver the benefits and innovations of IP without losing control of the network service. Users like the Internet to be free and high speed without extra charges for visiting specific sites. Such a service challenges the most valuable service in the telecommunications industry — voice — and threatens to change the nature of the global communications industry.

Fiber Optic

2008-04-13T20:12:00.000-07:00

Optical fiber consists of a core, cladding, and a protective outer coating, which guides light along the core by total internal reflection. The core, and the lower-refractive-index cladding, are typically made of high-quality silica glass, though they can both be made of plastic as well. An optical fiber can break if bent too sharply. Due to the microscopic precision required to align the fiber cores, connecting two optical fibers, whether done by fusion splicing or mechanical splicing, requires special skills and interconnection technology.[2].

Two main categories of optical fiber used in fiber optic communications are multi-mode optical fiber and single-mode optical fiber. Multimode fiber has a larger core (≥ 50 micrometres), allowing less precise, cheaper transmitters and receivers to connect to it as well as cheaper connectors. However, multi-mode fiber introduces multimode distortion which often limits the bandwidth and length of the link. Furthermore, because of its higher dopant content, multimode fiber is usually more expensive and exhibits higher attenuation. Single-mode fiber’s smaller core (<10 micrometres) necessitates more expensive components and interconnection methods, but allows much longer, higher-performance links.

In order to package fiber into a commercially-viable product, it is protectively-coated, typically by using ultraviolet (UV) light-cured acrylate polymers, terminated with optical fiber connectors, and assembled into a cable. It can then be laid in the ground, run through a building or deployed aerially in a manner similar to copper cable. Once deployed, such cables require substantially less maintenance than copper cable.

GSM at the next time

2008-04-12T07:08:00.000-07:00

Metaversatility teamed up with GSD&M. GSD&M has been trying to be a player in the virtual worlds data game for a while. They took a big lead in the Second Life Market Data Project that ultimately wound up being abandoned - in my opinion from watching the progress - due to a lack of expertise toward developing virtual world appropriate research methodologies. So it makes terrific sense for GSD&M to partner with Metaversatility to help them gain that expertise and the appropriate resources.

Metaversatility is also providing GSD&M's IdeaCity with a branded research “bot” to automatically screen and survey avatars in-world, rather than using “out of world” web-based surveys.

This in-world surveying has value from the standpoint the person behind the avatar is “in” the environment being researched. So, it will be interesting to see if IdeaCity’s results differ significantly from other researchers’ based on this approach.

However, I think GSD&M’s characterization of their new research service as “ethnographic” is using the term rather loosely. Ethnographic study deeply involves the researching human who is observing in a native environment – generally over a long period of time. By its nature, it is not objective research. Bots don’t fall into that definition, at least not yet. This is qualitative research, to be sure, but the mere fact that surveys or interviews are done in world doesn’t make it ethnographic research. Maybe there is more to their ethnographic story, so hopefully someone from Metaversatility or GSD&M will step in here and provide more context.

I’ll forgive (soon) both GSD&M and Metaversatility for the blatant PR spin in their press release generalizing the “gaping void” in “best in class virtual world research.” There has been enormous amounts of truly impressive research going on for years in virtual environments (academic and commercial); several consultancies and agencies have been quietly affording clients data and research-informed advice and solutions. A few have distinguished themselves as leaders in 3D virtual spaces. Metaversatility has itself had various research services as part of their client offerings since they were founded, and members of their team have shared their research at past conferences, including VW2008 this week.

No matter the details, I wish them each success. The entire community will gain from more research being done in virtual spaces and these are two partnerships that can only help further everyone’s knowledge about these environments and the people who inhabit them. Even if the research these companies undertake isn’t widely shared or made available, it will leak out in the form of better initiatives, case studies, new services, and a higher degree of client satisfaction.

GSM and CDMA technology

2008-04-12T06:24:00.000-07:00

GSM (Global System for Mobile Communications) is a form of multiplexing, which divides the available bandwidth among the different channels.

GSM is a combination of Time and Frequency-Division Multiple Access (TDMA/FDMA). The FDMA part involves the division by frequency of the (maximum) 25 MHz bandwidth into 124 carrier frequencies spaced 200 kHz apart. Each of these carrier frequencies is then divided in time, using a TDMA scheme. The fundamental unit of time in this TDMA scheme is called a burst period and it lasts 15/26 ms (or approx. 0.577 ms). Eight burst periods are grouped into a TDMA frame (120/26 ms, or approx. 4.615 ms), which forms the basic unit for the definition of logical channels. One physical channel is one burst period per TDMA frame. Thus GSM allows eight simultaneous calls on the same radio frequency.

CDMA (Code Division Multiple Access) is a form of multiplexing (access to the same resource will be given to more than one user),which allows the use of a particular frequency for a number of signals, optimizing the use of available bandwidth. It is a cellular technology that uses spread-spectrum techniques. In CDMA technology every channel uses the full available spectrum. Individual conversations are encoded with a pseudo-random digital sequence.

CDMA employs analog-to-digital conversion (ADC) in combination with spread spectrum technology. Audio input is first digitized (ADC) into binary elements. The frequency of the transmitted signal is then made to vary according to a defined pattern (code), so it can be intercepted only by a receiver whose frequency response is programmed with the same code, so it follows exactly along with the transmitter frequency. There are trillions of possible frequency-sequencing codes; this enhances privacy and makes cloning difficult. The technology is used in ultra-high-frequency (UHF) cellular telephone systems in the 800-MHz and 1.9-GHz bands.

GSM was first introduced in 1991 and until recently before the establishment of CDMA networks, GSM was the only mobile communication system present in the market. CDMA was first used during World War II by the English allies to foil German attempts at jamming transmissions. The allies decided to transmit over several frequencies, instead of one, making it difficult for the Germans to pick up the complete signal.

Since bandwidth is the major problem in the modern times the CDMA has a very clear advantage over the GSM in these terms. The number of channels(users) that can be allocated in a given bandwidth is comparatively higher for CDMA than for GSM. The cost of setting up a CDMA network is also comparatively less than the GSM network. Due to these advantages there is high probability that CDMA technology will dominate the future of mobile communications.

About GSM

2008-04-12T06:17:00.000-07:00

GSM networks are leaders in many typically &digital& services including the Short Message Service (SMS), Over the air (OTA) configuration and GSM positionning. Considered its technology and presence both in Americas and the rest of the world, GSM is in a good position for global roaming and many new GSM phones are called &global phones&, since they can be used in virtually any country. The SIM card (&Subscriber Identification Module&) is also a unique and essential component of GSM phones. Technically, GSM was built based on the TDMA protocol.

CDMA technology

2008-04-12T05:46:00.000-07:00

CDMA employs spread-spectrum technology and a special coding scheme (where each transmitter is assigned a code) to allow multiple users to be multiplexed over the same physical channel. By contrast, time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency. CDMA is a form of "spread-spectrum" signaling, since the modulated coded signal has a much higher bandwidth than the data being communicated.

An analogy to the problem of multiple access is a room (channel) in which people wish to communicate with each other. To avoid confusion, people could take turns speaking (time division), speak at different pitches (frequency division), or speak in different directions (spatial division). In CDMA, they would speak different languages. People speaking the same language can understand each other, but not other people. Similarly, in radio CDMA, each group of users is given a shared code. Many codes occupy the same channel, but only users associated with a particular code can understand each other.