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WAP: An Introduction                                                           

The Wireless Application Protocol (WAP) is a new advanced intelligent messaging service for digital mobile phones and other mobile terminals that will allow you to see Internet content in special text format on special WAP-enabled mobile phones. Enabling information access from handheld devices requires a deep understanding of both technical and market issues that are unique to the wireless environment. The WAP specification was developed by the industry’s best minds to address these issues. Wireless devices represent the ultimate constrained computing device with limited CPU, memory and battery life and a simple user interface. Wireless networks are constrained by low bandwidth, high latency and unpredictable availability and stability. The WAP specification addresses these issues by using the best of existing standards and developing new extensions when needed. The WAP solution leverages the tremendous investment in web servers, web development tools, web programmers and web applications while solving the unique problems associated with the wireless domain. The specification ensures that this solution is fast, reliable and secure. The WAP specification is developed and supported by the wireless telecommunication community so that the entire industry and its subscribers can benefit from a single, open specification. 

 The WAP forum                        

The WAP specification was developed by the WAP forum, a consortium founded by the telecommunication giants Nokia, Ericsson, Phone.com and Motorola. The WAP forum’s membership roster now includes computer industry heavyweights such as Microsoft, Oracle, IBM and Intel along with several hundred other companies. The WAP forum is an industry group dedicated to the goal of enabling sophisticated telephony and information services on handheld wireless devices. The WAP forum has drafted a global wireless protocol specification for all wireless networks and is contributing it to various industry groups and standard bodies.  This WAP specification by the WAP forum enables manufacturers, network operators, content providers and application developers to offer compatible products and secure services on all devices and networks, resulting in greater economies of scale and universal access to information.   

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Download Full Article 3g

Marconi’s innovative perception of electromagnetic waves and the air interface in 1897 was the first milestone on the important road to shared use of the radio spectrum. But only after almost a century later did mobile wireless communication start to take off. Despite a series of disappointing false starts, communication world in the late 1980’s was rapidly becoming more mobile for a much wider segment of communication users than ever before. With the advent of wireless technology, a transition from point-to-point communication toward person to-person communication (i.e.; independent of position) has begun. Testimony to this is the rapidly increasing penetration of cellular phones all across the world. In anticipation of the growing consumer demands, the next generation of wireless systems endeavors to provide person-to-person communication of the circuit and packet multimedia data.

The first generation cellular networks, which were based on analog technology with FM modulation, have been successfully deployed since the early and mid 1980’s. A typical example of a first generation cellular telephone system ( 1G ) is the Advanced Mobile Phone Services ( AMPS) . Second generation ( 2G ) wireless systems employ digital modulation and advanced call-processing capabilities. In view of the processing complexity required for these digital systems, two offered advantages are the possibility of using spectrally efficient radio transmission schemes such as Time Division Multiple Access ( TDMA ) or Code Division Multiple Access ( CDMA ), in comparison to the analog Frequency Division Multiple Access ( FDMA ) schemes previously employed and the provision for implementation of a wide variety of integrated speech and data services such as paging and low data rate network access. Examples of 2 G  wireless systems include the Global System for Mobile communication ( GSM ), TDMA IS-54/IS-136 and Personal Digital Cellular ( PDC ).

Third Generation ( 3G ) wireless systems will evolve from mature 2G networks with the aim of providing universal access and global roaming. More important these systems are expected to support multi dimensional (multi-information media, multi-transmission media, and multi-layered networks) high-speed wireless communication- an important milestone toward achieving the grand vision of ubiquitous personal communications. Introduction of wide band packet-data services for wireless Internet up to 2Mbps will be the main attribute of 3G system.

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Download Full Article Voice User Interface

Definition

In its most generic sense a voice portal can be defined as “speech enabled access to Web based information”. In other words, a voice portal provides telephone users with a natural language interface to access and retrieve Web content. An Internet browser can provide Web access from a computer but not from a telephone. A voice portal is a way to do that.

Overview

The voice portal market is exploding with enormous opportunities for service providers to grow business and revenues. Voice based internet access uses rapidly advancing speech recognition technology to give users any time, anywhere communication and access-the Human Voice- over an office, wireless, or home phone. Here we would describe the various technology factors that are making voice portal the next big opportunity on the web, as well as the various approaches service providers and developers of voice portal solutions can follow to maximize this exciting new market opportunity.

Why Voice?

Natural speech is modality used when communicating with other people. This makes it easier for a user to learn the operation of voice-activate services. As an output modality, speech has several advantages. First, auditory input does not interfere with visual tasks, such as driving a car. Second, it allows for easy incorporation of sound-based media, such as radio broadcasts, music, and voice-mail messages. Third, advances in TTS (Text To Speech) technology mean text information can be transferred easily to the user. Natural speech also has an advantage as an input modality, allowing for hands-free and eyes-free use. With proper design, voice commands can be created that are easy for a user to remember .These commands do not have to compete for screen space. In addition unlike keyboard-based macros (e.g., ctrl-F7), voice commands can be inherently mnemonic (“call United Airlines”), obviating the necessity for hint cards. Speech can be used to create an interface that is easy to use and requires a minimum of user attention.

VUI (Voice User Interface)

 For a voice portal to function, one of the most important technology we have to include is a good VUI (Voice User Interface).There has been a great deal of development in the field of interaction between human voice and the system. And there are many other fields they have started to get implemented. Like insurance has turned to interactive voice response (IVR) systems to provide telephonic customer self-service, reduce the load on call-center staff, and cut overall service costs. The promise is certainly there, but how well these systems perform-and, ultimately, whether customers leave the system satisfied or frustrated-depends in large part on the user interface.

Many IVR applications use Touch-Tone interfaces-known as DTMF (dual-tone multi-frequency)-in which customers are limited to making selections from a menu. As transactions become more complex, the effectiveness of DTMF systems decreases.

In fact, IVR and speech recognition consultancy Enterprise Integration Group (EIG) reports that customer utilization rates of available DTMF systems in financial services, where transactions are primarily numeric, are as high as 90 percent; in contrast, customers’ use of insurers’ DTMF systems is less than 40 percent.
Enter some more acronyms. Automated speech recognition (ASR) is the engine that drives today’s voice user interface (VUI) systems. These let customers break the ‘menu barrier’ and perform more complex transactions over the phone. “In many cases the increase in self-service when moving from DTMF to speech can be dramatic,” said EIG president Rex Stringham.

The best VUI systems are “speaker independent”-they understand naturally spoken dialog regardless of the speaker.  And that means not only local accents, but regional dialects, local phrases such as “pop” versus “soda,” people who talk fast (you know who you are), and all the various nuances of speech. Those nuances are good for human beings; they allow us to recognize each other by voice. For computers, however, they make the process much more difficult. That’s why a handheld or pocket computer still needs a stylus, and why the ‘voice dialing’ offered by some cell-phone companies still seems high-tech.

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Download Full Article Voice Over Internet Protocol

I N T R O D U C T I O N

Using an ordinary phone for most people is a common daily occurrence as is listening to your favorite CD containing the digitally recorded music. It is only a small extension to these technologies in having your voice transmitted in data packets. The transmission of voice in the phone network was done originally using an analog signal but this has been replaced in much of the world by digital networks. Although many of our phones are still analog, the network that carries that voice has become digital.

In todays phone networks, the analog voice going into our analog phones is digitized as it enters the phone network. This digitization process, shown in Figure 1 below, records a sample of the loudness (voltage) of the signal at fixed intervals of time. These digital voice samples travel through the network one byte at a time.

At the destination phone line, the byte is put into a device that takes the voltage number and produces that voltage for the destination phone. Since the output signal is the same as the input signal, we can understand what was originally spoken.
The evolution of that technology is to take numbers that represent the voltage and group them together in a data packet similar to the way computers send and receive information to the Internet. Voice over IP is the technology of taking units of sampled speech data .

So at its most basic level, the concept of VoIP is straightforward. The complexity of VoIP comes in the many ways to represent the data, setting up the connection between the initiator of the call and the receiver of the call, and the types of networks that carry the call.

Using data packets to carry voice is not just done using IP packets. Although it won’t be discussed, there is also voice over Frame Relay (VoFR) and Voice over ATM (VoATM) technologies. Many of the issues VoIP being discussed also apply to the other packetized voice technologies.

The increasing multimedia contents in Internet have reduced drastically the objections to putting voice on data networks. Basically, the Internet objections to putting voice on data networks. Basically, the Internet Telephony is to transmit multimedia information in discrete packets like voice or video over Internet or any other IP-based Local Area Network (LAN) or Wide Area Network (WAN). The commercial Voice Over IP (Internet Protocol) was introduced in early 1995 when VocalTec introduced its Internet telephone software. Because the technologies and the market have gradually reached their maturity, many industry leading companies have developed their products for Voice Over IP applications since 1995.

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Download Full Article  Virtual LAN

                        In today’s networked backbone, there are certain hardware devices that connect other networks to the backbone. These are special purpose devices and computers that just transfer messages from one network to another. Before we look deep into the topic Virtual LAN’s, let us see the basic devices used in the network backbone. They are

1. Bridges.

                                           2. Switches.

3. Routers.

4. Gateways.

5. Hubs.

BRIDGES-Bridges operate at the data link layer.  They connect two LAN segments that use the same data link and network protocol.  They may use the same or different types of cables.  Bridges “learn” whether to forward packets, and only forward those messages that need to go to other network segments.

                        If a bridge receives a packet with a destination address that is not in the address table, it forwards the packet to all networks or network segments except the one on which it was received. Bridges are a combination of both hardware and software, typically a “black box” that sits between the two networks, but can also be a computer with two NICs and special software.

SWITCHES-Like bridges, switches operate at the data link layer. Switches connect two or more computers or network segments that use the same data link and network protocol. They may connect the same or different types of cable. The switch is a device that connects a material coming in with an appropriate outlet. They require more processing power. Switches operate at the same layers as bridges but differ from them in two ways:

1. First, most switches enable all ports to be in use simultaneously, making them faster than bridges.

2. Second, unlike bridges, switches don’t learn addresses, and need to have addresses defined.

There are two types of switches:

1. Cut-through switches examine the destination of the incoming packet and immediately connect the port with the incoming message to the correct outgoing port. It is hardware-based.

2. Store-and-forward switches copy the incoming packet into memory before processing the destination address.

ROUTERS-Routers operate at the network layer.  Routers connect two or more LANs that use the same or different data link protocols, but the same network protocol.  Routers may be “black boxes,” computers with several NICs, or special network modules in computers.

In general they perform more processing on each message than bridges and therefore operate more slowly.

                        Routers can choose the best route when compared with bridges .They only process messages specifically addressed to it. Routers can connect networks using different data link layer protocols. Therefore, routers are able to change data link layer packets. Routers may split a message into several smaller messages for better transmission.

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