With all of the recent media hype surrounding mobile WiMAX, the term "wireless broadband" has grown almost synonymous with WiMAX. Mobile WiMAX, or IEEE 802.16e-2005, promises to provide a wireless alternative to wired broadband like cable or digital subscriber line (DSL). Because it does not require line-of-sight connectivity, it promises to provide high-speed access to many areas that currently cannot be served by wired technologies. Despite these impressive claims, mobile WiMAX is not the only broadband technology making waves in the current market. Within the home, for example, Ultra Wideband (UWB) vows to eliminate wires while enabling the delivery of video and other data between home-entertainment and PC-related devices. Clearly, the mission of both of these technologies is to transmit data. The ongoing work of many companies is making sure that they deliver on that promise.

When it comes to mobile WiMAX, its fate-rather, its success-seems already sealed. An oft-quoted industry rule of thumb is, "Where Intel goes, the world will follow." When it comes to its influence in the PC market, Intel (www.intel.com) does seem to be the largest driver of new trends-especially wireless ones. Just look at how Intel Centrino brought IEEE 802.11x wireless-local-area-networking (WLAN) into the mainstream. In 2008, select Intel Centrino processor-technology-based notebooks will feature the world's first integrated, embedded WiFi/mobile-WiMAX solution. Code named "Echo Peak," this move proves that Intel believes that many consumers will adopt mobile WiMAX as a vital part of their daily lives.

More validation of mobile WiMAX recently came from Cisco (www.cisco.com), which announced that it will acquire Navini Networks (www.navini.com) for $330 million. According to ABI Research (www.abiresearch.com), this move will allow Cisco to expand on its solutions for enterprise customers in developed countries while continuing its planned expansion into developing markets. Navini is a respected name in the mobile-WiMAX arena. Last month, the company took part in a landmark demonstration with Fujitsu Microelectronics America, Inc. (http://us.fujitsu.com)-another early proponent of WiMAX. The companies announced the first demonstration of multi-vendor interoperability using Smart WiMAX technology (Fig. 1). Smart WiMAX-a concept that was developed by Navini-combines smart beamforming with multiple input/multiple output (MIMO) on an IEEE 802.16e network. Smart WiMAX systems are expected to provide an estimated doubling of system capacity. In a fully mobile setting, they also will offer up to twice the coverage of simple WiMAX networks.

The demonstration, which took place in Navini's test facility in Richardson, TX, used Navini's Ripwave MX8 base station running mobile WiMAX software and a customer-premise-equipment (CPE) reference-design prototype based on the Fujitsu MB86K21 802.16e-2005 mobile WiMAX chip. Smart WiMAX beamformed connectivity was achieved using "dedicated pilots," which are a mandatory feature for all Wave 2 Mobile Station subscriber devices required for certification under published WiMAX Forum (www.wimaxforum.org) profiles. Navini is working with partners like Fujitsu to extend the capabilities of Smart WiMAX to include beamformed MIMO, which can double received data rates and improve the reliability of a mobile signal.

That demonstration is only one of the recent displays of mobile WiMAX's capabilities. Toward the end of September, Motorola (www.motorola.com) conducted the first IEEE IEEE 802.16e-2005 mobile handoffs in downtown Chicago. Attendees experienced uninterrupted mobile applications including web browsing, voice-over-IP (VoIP) calls, video streaming, and MobiTV while moving past access point sites along the route of a cruise. The company also demonstrated several of these applications on streets along the Chicago River while both driving at speeds beyond 50 mph and riding Chicago's elevated train.

The array of devices used during this demonstration included Motorola's trial mobile-WiMAX handset, which was developed for high-speed video telephony and laptops enabled with the company's WiMAX PC cards. The network infrastructure comprised standard Motorola WAP 25400 access points with backhaul provided by the company's wireless IP backhaul equipment to its Innovation Center in Schaumburg, IL. There, a Motorola IMS provided connection to the public switched telephone network. The WAP 25400 access point is part of Motorola's WAP 400 series, which features diversity antenna techniques and provides non-line-of-sight, fixed and mobile wireless broadband connections. These access points are based on the IEEE 802.16e-2005 standard. They include a spectrally efficient S-OFDMA interface, low latency performance, and an IP-based architecture.

The Chicago market is one of six in the US that Sprint has awarded to Motorola to build a WiMAX network infrastructure to support its recently announced Xohm mobile Internet services. With Xohm, the carrier promises that customers will be able to experience a new form of interactive communications, high-speed Internet browsing, local and location-centric services, and multimedia services including music, video, TV and on-demand products. Sprint also plans to bring Xohm WiMAX mobile Internet customers search, interactive communications, and social-networking tools through a new mobile portal in a deal announced with Google.

According to Thomas Gratzek, Business Director for Analog Devices' (www.analog.com) WiMAX Transceiver Group, "We are seeing more and more networks in test and deployment phase. Sprint's Xohm is certainly driving toward marketing this to consumers in the US. We are seeing networks and ecosystems being developed and prepared in Korea, Taiwan, and Japan. Thus, this segment will most likely have explosive growth over the next couple of years all across the world. It may not meet a specific forecast. But from a standstill, it will meet many people's expectations."

Proof of mobile WiMAX's progress also is evidenced by Alcatel-Lucent (www.alcatel-lucent.com), which has secured 15 commercial contracts and more than 70 pilots based on the latest IEEE 802.16e-2005 standard. The company has been converting trials into commercial contracts at a rate of two per month for the last six months. It credits cutting-edge technologies like beamforming and multiple-input multiple output for much of its success. Beamforming, which is a key feature of the 802.16e-2005 standard, is designed to steer and focus radio signals toward end-user terminals instead of spreading it in all directions. As a result, it increases signal strength and quality. According to results measured on customer networks, beam forming has improved coverage by up to 50 percent and throughput by up to 30 percent. These performance increases are independent of the type of terminal being used.

On its commercial equipment, Alcatel-Lucent also has demonstrated the simultaneous use-in a single sector-of two MIMO downlink technologies: space-time block coding (STBC) and spatial multiplexing (SM). MIMO STBC enables the establishment of a more robust WiMAX signal by leveraging spatial diversity. In doing so, it improves the data rate in adverse radio conditions up to 30 percent. MIMO SM increases data rates by sending different signals on each of the two WiMAX base-station antennas, thereby doubling throughput.

Infrastructure also is the focus of a recent development announcement from Hitachi Communication Technologies (www.hitachi-com.com) and Alvarion (www.alvarion.com). They recognized that two things were needed for the establishment of mobile WiMAX: a base station that can transmit broadband data stably and mobile management technology that can realize seamless handovers between base stations. Through a development agreement, the companies will develop system solutions that combine the base-station technology of Alvarion with the mobile-gateway, construction, and maintenance technology of Hitachi Com.

Specifically, Hitachi Com is in charge of developing the Access Service Network Gateway (ASN-GW). Here, the common platform architecture is applied from a small system to very large systems so that it can be flexibly expanded by the future traffic increase through separating protocol processor from traffic processor. The gateway has a non-stop configuration to realize the quality of the carrier grade. As a result, it can switch to the redundant system without impacting other equipment, such as base stations and mobile stations, through the mirroring of operation information and the instantaneous transfer of IP addresses.

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