Q.1. What are 1G, 2G, 2.5G, 3G & 4G?
Ans: Technically generations are defined: 1G networks (NMT, AMPS, TACS) are considered to be the first analog cellular systems, which started early 1980s. There were radio telephone systems even before that. 2G networks (GSM, cdmaOne, DAMPS) are the first digital cellular systems launched early 1990s. 2.5G networks (GPRS, cdma2000 1x) are the enhanced versions of 2G networks with data rates up to about 144kbit/s. 3G networks (UMTS FDD and TDD, cdma2000 1x EVDO, cdma2000 3x, TD-SCDMA, Arib WCDMA, EDGE,IMT-2000 DECT) are the latest cellular networks that have data rates 384kbit/s and more. 4G is mainly a marketing buzzword at the moment. Some basic 4G research is being done, but no frequencies have been allocated. The Forth Generation could be ready for implementation around 2012.
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Q.2.What is UMTS?
Q.4. How is UMTS different from current second generation networks?
Ans: Universal Mobile Telecommunications System is the European implementation of the 3G wireless phone system. UMTS, which is part of IMT-2000, provides service in the 2GHz band and offers global roaming and personalized features. Designed as an evolutionary system for GSM network operators, multimedia data rates up to 2 Mbps are expected using WCDMA. The UMTS is not a replacement of 2nd generation technologies (e.g. GSM, DCS1800, CDMA, DECT etc.), which will continue to evolve to their full potential.
Q.3 .What is the difference between cdma2000 and UMTS?
Ans: Cdma2000 and UMTS were developed separately and are 2 separate ITU approved 3G standards. Cdma2000 1xRTT, cdma2000 1xEV-DO (EVolution, Data Only) and future cdma2000 3x were developed to be backward compatible with cdmaOne. Both 1x types have the same bandwidth, chip rate and it can be used in any existing cdmaOne frequency band and network. Backward compatibility was a requirement for successful deployment for USA market. It is easy to implement because operators do not need new frequencies.
- Higher speech quality than current networks ,Addition to speech traffic UMTS, together with advanced data and information services, will be a multimedia network.
- UMTS is above 2G mobile systems for its potential to support 2Mbit/s data rates.
- UMTS is a real global system, comprising both terrestrial and satellite components.
- Consistent service environment even when roaming via "Virtual Home Environment" (VHE). A person roaming from his network to other UMTS operators, user will experience a consistent set of services thus "feeling" on his home network, independent of the location or access mode (satellite or terrestrial)
Q.5. What is the 3G status in the India?
Q.12. What is 3GPP and how is it related to 3G Wireless?
Ans: India's Bharti AirTel plans to roll out 3G services on a national level by end of 2006.Currently in India, GSM operators are at odds with CDMA operators over the future of 3G spectrum in the 1900 MHz band. I Reliance Infocomm, commercially launched Reliance IndiaMobile's, third-generation (3G) CDMA2000 1X services on May 1, 2003. The Reliance IndiaMobile service marks the first CDMA2000 1X nationwide commercial launch in India, bringing advanced wireless data and voice services.
Q.6. Will the future 3G handsets be compatible with 2G systems and PCs?
Ans: Some of the 3G mobiles will be dualband UMTS/GSM handsets (available late 2002?) and will be able to perform UMTS-GSM handovers. Current GSM phones will not work in 3G networks. Several SIM card manufacturers now offer cards compatible with 2G and 3G systems.
Q.7. How is 3G different to GSM or CDMA?
Ans: 3G differs from GSM and CDMA as it is a network operating at a different frequency to GSM and CDMA, allowing for faster speeds when using services on this network.
Q.8. Do I need a special kind of mobile phone?
Ans: To access specific features of 3G, you will require a compatible handset with an 3G SIM. Please check with sales staff to ensure your handset is 3G enabled.
Q.9. Will my MMS and SMS still work?
Ans: MMS and SMS will still work when you have a 3G phone.
Q.10. Is video calling only available on 3G?
Ans: Currently customers will only be able to access the video calling feature if they have a 3G SIM and a 3G mobile handset. Video calls can only be made in a 3G coverage area.
Q.11. What is the difference between 3G and 2.5G?
Ans: The term 3G refers to the next generation of wireless communications technology, the "first generation" having been analogue cellular, and the "second generation" (2g and 2.5G) being today's existing GSM/GPRS networks. 3G aims to provide universal, high-speed, high bandwidth support to bandwidth hungry applications such as full motion videos, video calling and full Internet access. Video Calling is one of the most exciting things about 3G is being able to see your friends as you are calling them.
Ans: The 3rd Generation Partnership Project (3GPP) is a collaboration agreement that was established in December 1998.The collaboration agreement brings together a number of telecommunications standards bodies which are known as“Organizational Partners”. The current Organizational Partners are ARIB, CCSA, ETSI, ATIS, TTA, and TTC. Their website is http://www.3gpp.org. 3GPP is in charge of standardising WCDMA technology that is the most popular 3G Wireless standard.
Q.13. What is TDD and FDD?
Ans: TDD stands for Time Division Duplex and FDD stands for Frequency Division Duplex. They are different modes of CDMA. In FDD mode of transmission both the Transmitter and the Receiver transmit simultaneously. This simultaneous transmission is possible because they are both on different frequencies. In TDD mode of operation either Transmitter or Receiver can transmit at one time. This is because they use the same frequency for the transmission.
Q.14. How is UMTS subscriber differentiated from a GSM subscriber?
Ans: UMTS subscriber differentiated from a GSM subscriber based on SIM card. For UMTS and GSM subscriiber the SIM is different. UMTS subscriber uses USIM while GSM one uses SIM.
Q.15. How is CDMA superior to TDMA?
Ans: It supports more calls in the same spectrum, and it dynamically allocates bandwidth more easily. Spectrum is extremely expensive; it has to be purchased from various governmental licensing authorities at auction, and sometimes these auctions have involved billions of dollars (or equivalent monetary value in other currencies). It represents a considerable investment by a carrier. Generally speaking, CDMA will carry between two and three times as many calls simultaneously as TDMA in the same amount of bandwidth. This is due to something known as "frequency reuse" .The other major advantage of CDMA is dynamic allocation of bandwidth. To understand this, it's important to realize that in this context in CDMA, "bandwidth" refers to the ability of any phone to get data from one end to the other. It doesn't refer to the amount of spectrum used by the phone, because in CDMA every phone uses the entire spectrum of its carrier whenever it is transmitting or receiving.
Q.16. What is Voice over IP (VoIP)?
Ans: The general goal behind Voice over IP, or IP Telephony, is to carry voice (telephone) traffic over the same network that carries data (computer) traffic.
Q.17. What’s the difference between VoIP and voice over the Internet?
Ans: Voice over IP system is NOT voice over the Internet. IP stands for Internet Protocol, which means that the voice is digitized into data packets so that it is compatible with being sent over data networks, including the Internet. HOWEVER, VoIP only carries the call in IP format from your desk phone to the other phones.
Q.18.How does VoIP work?
Ans: Many years ago it was discovered that sending a signal to a remote destination could have be done also in a digital fashion: before sending it we have to digitalize it with an ADC (analog to digital converter), transmit it, and at the end transform it again in analog format with DAC (digital to analog converter) to use it. VoIP works like that, digitalizing voice in data packets, sending them and reconverting them in voice at destination. Digital format can be better controlled:one can compress it, route it, convert it to a new better format, and so on; also digital signal is more noise tolerant than the analog one. TCP/IP networks are made of IP packets containing a header (to control communication) and a payload to transport data: VoIP use it to go across the network and come to destination.
Q.19. What are the advantages of using VoIP than PSTN?
Ans: When you are using PSTN line, you typically pay for time used to a PSTN line manager company: more time you stay at phone and more you'll pay. In addition you couldn't talk with other that one person at a time. In opposite with VoIP mechanism you can talk all the time with every person you want (the needed is that other person is also connected to Internet at the same time), as far as you want (money independent) and, in addition, you can talk with many people at the same time. If you're still not persuaded you can consider that, at the same time, you can exchange data with people are you talking with, sending images, graphs and videos.
Q.20. What is Symbian?
Ans: Symbian is a joint venture between Nokia, Motorola, Ericsson, Matsushita, and Psion, with Nokia as one of the founding members. Symbian was established by leaders in the computing and mobile industries to enable the mass market of communicators and smart phones. Symbian owns and develops the Symbian operating system that is optimized for mobile terminals, such as communicators and smart phones. Licensees: Mobile phone manufacturers that license Symbian OS are Arima, Ben Q, Fujitsu, Lenovo, LG Electronics, Motorola, Mitsubishi, Nokia, Panasonic, Samsung, Sharp and Sony Ericsson etc..
Q.21. What does Symbian OS enable?
- Small, feature-rich, mobile devices for a mass market
- Diversity of devices for consumers
- Faster time-to-market for platform vendors
- Open, standards-based platform for third-party application developers
- Excellent connectivity
- Advanced design
- High-performance, 32-bit OS with pre-emptive multitasking
- Long battery life
- Wide industry support and commitment
- Applications that can be designed once and run on multiple devices
- Nokia Series 60 and communicator platforms are based on Symbian OS
Q.22. Why choose Symbian OS as a development platform?
Q.23. How reliable is Symbian OS?
Ans: Because Symbian OS is written in C++, it is a fully object-oriented operating system. This contributes to its flexibility, efficiency ,and ability to re-use segments of the code. Clearly defined APIs allow the large developer community, including terminal vendors, to create applications that can be easily downloaded, installed, and run natively on the terminal Symbian OS. Symbian C++ APIs enable extremely efficient multitasking and memory management. Processor-and memory-intensive operations such as context switching are minimized. Symbian OS is primarily event driven rather than multithreaded, potentially saving several kilobytes of overhead per thread. The event-driven Symbian OS doesn't need any context switching and can have an overhead as low as a few tens of bytes.
Ans: Symbian OS was developed so that user data would never be lost and the device running the OS would never need to be rebooted. Symbian OS provides all the tools necessary for developers to deliver on this vision, including:
- Preventing memory leaks with effective memory management;
- Releasing resources as soon as they are no longer needed;
- Handling out-of-memory errors properly through an effective error-handling framework.
Q.25. Please describe the importance of WiMAX.
Q.32. What programming languages does the BREW platform support?
Ans: WiMAX, a data-on-the-go alternative to cable and DSL, is a standards-based broadband wireless access technology for enabling the last-mile delivery of information. WiMAX will provide fixed, nomadic, portable and, eventually, mobile wireless broadband connectivity without the need for direct line-of-sight connection between a base station and a subscriber station. In a typical cell radius deployment of 3 to 10 Km, WiMAX-certified systems can be expected to support capacity of up to 40Mbps per channel, for fixed and portable access applications. This is enough bandwidth to simultaneously support hundreds of businesses with T-1 speed connectivity and thousands of residences with DSL speed connectivity. Mobile network deployments are expected to provide up to 15Mbps of capacity within a typical cell-radius deployment of up to 3 Km. It is expected that WIMAX technology will be incorporated in notebook computers and PDAs starting as early as the end of 2006. WiMAX technology has the potential to enable service carriers to converge the all-IP-based network for triple-play services such as data, voice,and video.
Q.26, How far can WiMAX cover?
Ans: In a typical cell radius deployment of three to 10 kilometers, WiMAX can be expected to deliver capacity of up to 40 Mbps per channel, for fixed and portable access applications.
Q.27. Will WiMAX replace fiber? If so, when will this replacement occur?
Ans: Fiber and wireless will co-exist in the last mile. Wireless deployment will grow significantly over fiber due to ease of deployment and lower cost. However, in the near term, fiber will still be adopted for mission-critical applications that require near-zero interference and latency performance.
Q.28. Will WiMAX displace the existing landline and wireless technologies (e.g. WiFi)?
Ans: WiMAX and WiFi will coexist and become increasingly complementary technologies for their respective applications. WiMAX is typically not thought of as a replacement for WiFi. Rather, WiMAX complements WiFi by extending its reach and providing a 'WiFi-like' user experience on a larger geographical scale. WiFi technology was designed and optimized for Local Area Networks (LANs), whereas WiMAX was designed and optimized for Metropolitan Area Networks (MANs). In the 2006 -2008 timeframe, it is expected that both 802.16 and 802.11 capabilities will be available in end-user devices from laptops to PDAs, as both will deliver wireless connectivity directly to the end user - at home, in the office and on the move.
Q.29. What are the major differences between WiMAX and WiFi?
Ans: WiMAX technology theoretically supports a coverage radius of 30 miles and a data rate of up to 75 Mbps, while WiFi currently supports a much shorter radius and lower data rates. WiFi and WiMAX are different protocols, designed for different network situations and they don't really solve the same problem. WiFi belongs to the realm of local area network, while WiMAX is last mile replacement of Wired Broadband Access.
Q.30. What is WiMAX?
Ans: WiMAX is an acronym for World Wide Interoperability for Microwave Access. It a standards based wireless technology that provides high throughput broadband connection over long distance. The WiMAX based voice service can work on either traditional Time Division Multiplexed or VoIP.
Q. 31. How does BREW solve the issue of developing applications and services for wireless handsets?
Ans: The BREW platform is a standard environment for applications development for wireless handsets - from inexpensive, mass-market phones to high-end multi-purpose wireless devices. The platform lets you write applications that can be used on a wide variety of phones, without requiring modification of the app for each new phone model. BREW eliminates current programming challenges such as not having internal knowledge of the phone and its software.
Ans: BREW is intended to be neutral about development languages. Native C and C++ applications will run most efficiently. While there are currently certain limitations on the use of C++, we're working to remove these. BREW will also support integration of Java applications, provided a Java Virtual Machine is available on the device, browsers (WAP, CHTML, etc.) and other environments.
Q.33. What is BREW?
Ans: (Binary Runtime Environment for Wireless) An application development environment from Qualcomm for enhanced cellphone services (e-mail, games, etc.). BREW is directly supported in the CDMA chipsets from Qualcomm, and BREW-enabled applications work no matter what the underlying system software in the cellphone handset. Originally developed for Qualcomm's CDMA technology, BREW has been extended to GSM and TDMA cellular systems.
Q.34. What is SIP?
Ans: The Session Initiation Protocol (SIP) is a signalling protocol used for establishing sessions in an IP network. A session could be a simple two-way telephone call or it could be a collaborative multi-media conference session. Over the last couple of years, the Voice over IP community has adopted SIP as its protocol of choice for signaling. SIP is an RFC standard (RFC 3261) from the Internet Engineering Task Force (IETF), the body responsible for administering and developing the mechanisms that comprise the Internet. The IETF’s philosophy is one of simplicity: specify only what you need to specify. SIP is very much of this mould; it just initiates, terminates and modifies sessions. This simplicity means that SIP scales, it is extensible, and it sits comfortably in different architectures and deployment scenarios.
Q.35. What is Bluetooth?
Ans: Bluetooth is the name for a short-range radio frequency (RF) technology that operates at 2.4 GHz and is capable of transmitting voice and data. The effective range of Bluetooth devices is 32 feet (10 meters). Bluetooth transfers data at the rate of 1 Mbps, which is from three to eight times the average speed of parallel and serial ports, respectively.
Q.36. Why is the technology called Bluetooth?
Ans: The heart of the Bluetooth brand identity is the name, which refers to the Danish king Harald "Bluetooth" Blaatand who unified Denmark and Norway. In the beginning of the Bluetooth wireless technology era, Bluetooth was aimed at unifying the telecom and computing industries.
Q.37. How is Bluetooth used?
Ans: Bluetooth can be used to wirelessly synchronize and transfer data among devices. Bluetooth can be thought of as a cable replacement technology. Typical uses include automatically synchronizing contact and calendar information among desktop, notebook and palmtop computers without connecting cables. Bluetooth can also be used to access a network or the Internet with a notebook computer by connecting wirelessly to a cellular phone.
Q.38. What is the future direction of the Bluetooth standard?
Ans: At this time, we anticipate the Bluetooth SIG to evolve the Bluetooth technology to provide greater bandwidth and distances, thus increasing the potential platforms and applications used in the emerging personal area networking marketplace
Q.39. How secure is a Bluetooth network?
Ans: Bluetooth is extremely secure in that it employs several layers of data encryption and user authentication measures. Bluetooth devices use a combination of the Personal Identification Number (PIN) and a Bluetooth address to identify other Bluetooth devices. Data encryption (i.e., 128-bit) can be used to further enhance the degree of Bluetooth security. The transmission scheme (FHSS) provides another level of security in itself. Instead of transmitting over one frequency within the 2.4 GHz band, Bluetooth radios use a fast frequency-hopping spread spectrum (FHSS) technique, allowing only synchronized receivers to access the transmitted data.
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