Fixed and Mobile Wimax

Fixed and Mobile Wimax

Within the last two decades, communication advances have reshaped the way we live our daily lives. Wireless communications has grown from an obscure, unknown service to an ubiquitous technology that serves almost half of the people on Earth. Whether we know it or not, computers now play a dominant role in our daily activities, and the Internet has completely reoriented the way people work, communicate, play, and learn.

However severe the changes in our lifestyle may seem to have been over the past few years, the convergence of wireless with the Internet is about to unleash a change so dramatic that soon wireless ubiquity will become as pervasive as paper and pen. WiMax—which stands for Worldwide Interoperability for Microwave Access—is about to bring the wireless and Internet revolutions to portable devices across the globe. Just as broadcast television in the 1940’s and 1950’s changed the world of entertainment, advertising, and our social fabric, WiMax is poised to broadcast the Internet throughout the world, and the changes in our lives will be dramatic. In a few years, WiMax will provide the capabilities of the Internet, without any wires, to every living room, portable computer, phone, and handheld device.

In its simplest form, WiMax promises to deliver the Internet throughout the globe, connecting the “last mile” of communications services for both developed and emerging nations.

Broadband wireless sits at the confluence of two of the most remarkable growth stories of the telecommunications industry in recent years. Both wireless and broadband have on their own enjoyed rapid mass-market adoption. Wireless mobile services grew from 11 million subscribers worldwide in 1990 to more than 2 billion in 2005. During the same period, the Internet grew from being a curious academic tool to having about a billion users.

This staggering growth of the Internet is driving demand for higher-speed Internet-access services, leading to a parallel growth in broadband adoption. In less than a decade, broadband subscription worldwide has grown from virtually zero to over 200 million . Will combining the convenience of wireless with the rich performance of broadband be the next frontier for growth in the industry? Can such a combination be technically and commercially viable? Can wireless deliver broadband applications and services that are of interest to the end-users? Many industry observers believe so. Before we delve into broadband wireless, let us review the state of broadband access today. Digital subscriber line (DSL) technology, which delivers broadband over twisted-pair telephone wires, and cable modem technology, which delivers over coaxial cable TV plant, is the predominant mass-market broadband access technologies today. Both of these technologies typically provide up to a few megabits per second of data to each user, and continuing advances are making several tens of megabits per second possible. Since their initial deployment in the late 1990s, these services have enjoyed considerable growth. The United States has more than 50 million broadband subscribers, including more than half of home Internet users. Worldwide, this number is more than 200 million today and is projected to grow to more than 400 million by 2010 . The availability of a wireless solution for broadband could potentially accelerate this growth. What are the applications that drive this growth? Broadband users worldwide are finding that it dramatically changes how we share information, conduct business, and seek entertainment. Broadband access not only provides faster Web surfing and quicker file downloads but also enables several multimedia applications, such as real-time audio and video streaming, multimedia conferencing, and interactive gaming. Broadband connections are also being used for voice telephony using voice-over-Internet Protocol (VoIP) technology.

More advanced broadband access systems, such as fiber-to-the-home (FTTH) and very high data rate digital subscriber loop (VDSL), enable such applications as entertainment-quality video, including high-definition TV (HDTV) and video on demand (VoD). As the broadband market continues to grow, several new applications are likely to emerge, and it is difficult to predict which ones will succeed in the future.

So what is broadband wireless? Broadband wireless is about bringing the broadband experience to a wireless context, which offers users certain unique benefits and convenience. There are two fundamentally different types of broadband wireless services. The first type attempts to provide a set of services similar to that of the traditional fixed-line broadband but using wireless as the medium of transmission. This type, called fixed wireless broadband, can be thought of as a competitive alternative to DSL or cable modem. The second type of broadband wireless, called mobile broadband, offers the additional functionality of portability, nomadicity,1 and mobility.

Mobile broadband attempts to bring broadband applications to new user experience scenarios and hence can offer the end user a very different value proposition. WiMax (worldwide interoperability for microwave access) technology,

1.2 Necessity
In many parts of the world, existing fixed-line carriers that do not own cellular, PCS, or 3G spectrums could turn to WiMax for provisioning mobility services. As the industry moves along the path of quadruple-play service bundles—voice, data, video, and mobility—some service providers that do not have a mobility component in their portfolios—cable operators, satellite companies, and incumbent phone companies—are likely to find WiMax attractive. For many of these companies, having a mobility plan will be not only a new revenue opportunity but also a defensive play to mitigate churn by enhancing the value of their product set.

Existing mobile operators are less likely to adopt WiMax and more likely to continue along the path of 3G evolution for higher data rate capabilities. There may be scenarios, however, in which traditional mobile operators may deploy WiMax as an overlay solution to provide even higher data rates in targeted urban centers or metro zones. In addition to higher-speed Internet access, mobile WiMax can be used to provide voiceover- IP services in the future. The low-latency design of mobile WiMax makes it possible to deliver VoIP services effectively. VoIP technologies may also be leveraged to provide innovative new services, such as voice chatting, push-to-talk, and multimedia chatting. New and existing operators may also attempt to use WiMax to offer differentiated personal broadband services, such as mobile entertainment.

The flexible channel bandwidths and multiple levels of quality-of-service (QoS) support may allow WiMax to be used by service providers for differentiated high-bandwidth and low-latency entertainment applications. For example, WiMax could be embedded into a portable gaming device for use in a fixed and mobile environment for interactive gaming. Other examples would be streaming audio services delivered to MP3 players and video services delivered to portable media players. As traditional telephone companies move into the entertainment area with IP-TV (Internet Protocol television), portable WiMAX could be used as a solution to extend applications and content beyond the home.

5.1 Conclusion
WiMax offers benefits for wire line operators who want to provide last mile access to residences and businesses, either to reduce costs in their own operating areas, or as a way to enter new markets. 802.16e offers cost reductions to mobile operators who wish to offer broadband IP services in addition to 2G or 3G voice service, and allows operators to enter new markets with competitive services, despite owning disadvantaged spectrum. The capital outlay for WiMAX equipment will be less than for traditional 2G and 3G wireless networks, although the supporting infrastructure of cell sites, civil works, towers and so on will still be needed. WiMax’s all-IP architecture lends itself well to high bandwidth multi-media applications, and with QoS will also support mobile voice and messaging services, re-using the mobile networks IP core systems.

The latest developments in the IEEE 802.16 group are driving a broadband wireless access revolution to a standard with unique technical characteristics. In parallel, the WiMax forum, backed by industry leaders, helps the widespread adoption of broadband wireless access by establishing a brand for the technology. Initially, WiMax will bridge the digital divide and thanks to competitive equipment prices, the scope of WiMax deployment will broaden to cover markets with high DSL unbundling costs or poor copper quality which have acted as a brake on extensive high-speed Internet and voice over broadband. WiMax will reach its peak by making Portable Internet a reality. When WiMax chipsets are integrated into laptops and other portable devices, it will provide high-speed data services on the move, extending today's limited coverage of public WLAN to metropolitan areas.

Integrated into new generation networks with seamless roaming between various accesses, it will enable end-users to enjoy an "Always Best Connected" experience. The Combination of these capabilities makes WiMax attractive for a wide diversity of people: fixed operators, mobile operators and wireless ISPs (Internet Service Provider), but also for many vertical markets and local authorities. Alcatel, the worldwide broadband market leader with a market share in excess of 37%, is committed to offer complete support across the entire investment and operational cycle required for successful deployment of WiMax services

 • WiMax is based on a very flexible and robust air interface defined by the IEEE 802.16
The WiMax physical layer is based on OFDM, which is an elegant and effective technique for overcoming multipart distortion.
The physical layer supports several advanced techniques for increasing the reliability of
The link layer. These techniques include powerful error correction coding, including turbo
coding and LDPC, hybrid-ARQ, and antenna arrays.
WiMax supports a number of advanced signal-processing techniques to improve overall
system capacity. These techniques include adaptive modulation and coding, spatial multiplexing, and multi-user diversity.
WiMax has a very flexible MAC layer that can accommodate a variety of traffic types,
Including voice, video, and multimedia, and provide strong QoS.
Robust security functions, such as strong encryption and mutual authentication, are built
Into the WiMax standard.
WiMax has several features to enhance mobility-related functions such as seamless handover and low power consumption for portable devices.
WiMax defines a flexible all-IP-based network architecture that allows for the exploitation of all the benefits of IP. The reference network model calls for the use of IP-based protocols to deliver end-to-end functions, such as QoS, security, and mobility
WiMax offers very high spectral efficiency, particularly when using higher-order MIMO solutions.

5.2 Future scope
The IEEE 802.16m standard is the core technology for the proposed Mobile WiMax Release 2, which enables more efficient, faster, and more converged data communications. The IEEE 802.16m standard has been submitted to the ITU for IMT-Advanced standardization. IEEE 802.16m is one of the major candidates for IMT-Advanced technologies by ITU. Among many enhancements, IEEE 802.16m systems can provide four times faster data speed than the current Mobile WiMax Release 1 based on IEEE 802.16e technology.

Mobile WiMax Release 2 will provide strong backward compatibility with Release 1
solutions. It will allow current Mobile WiMax operators to migrate their Release 1 Solutions to Release 2 by upgrading channel cards or software of their systems. Also, the subscribers who use currently available Mobile WiMax devices can communicate with new Mobile WiMax Release 2 systems without difficulty.

It is anticipated that in a practical deployment, using 4X2 MIMO in the urban micro cell scenario with only a single 20 MHz TDD channel available system wide, the 802.16m system can support both 120 Mbit/s downlink and 60 Mbit/s uplink per site simultaneously. It is expected that the WiMax Release 2 will be available commercially in the 2011-2012 time frame The goal for the long-term evolution of WiMax is to achieve 100 Mbit/s mobile and 1 Gbit/s fixed-nomadic bandwidth as set by ITU for 4G NGMN (Next Generation Mobile Network).

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