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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For its part, Alvarion is in charge of developing high-performance macro/micro base stations. These base stations promise to realize a reduction in size and weight by function aggregation (unified RF and digital-processing parts, 30-percent less power consumption, and 50-percent less mass). They also reduce installation work cost. The base stations will be compatible with AAS and MIMO-two keys to the WiMAX Forum Wave 2 specifications. As a result of combining MIMO and AAS together, effective cell design should be accomplished more easily. Area coverage and system capacity also will increase.
To keep mobile WiMAX's development on track, a plethora of companies are developing products that make it easier to integrate mobile WiMAX. Reference kits, for example, are becoming more numerous. Lime Microsystems just launched the first reference design for the MicroTCA WiMAX transceiver platform (see sidebar, "Reference Design Targets WiMAX Transceiver"). Because mobile WiMAX is being integrated into portable devices, power consumption is a major concern. In September, SiGe Semiconductor (www.sige.com) announced plans to deliver a series of WiMAX RF front-end modules. The goal of these devices is to improve battery life and performance for consumer-electronic products. The module, which is based on the company's high-performance power amplifier, will deliver over 20-percent efficiency at +24-dBm output power. Each module will incorporate all of the circuitry that is required between the transceiver and antenna including the power amplifier, power detectors, filters, switches, and matching and bias components (Fig. 2). The series is scheduled to begin rolling out in early 2008.
The hype surrounding mobile WiMAX seems to have all but eclipsed the fixed version of WiMAX, dubbed IEEE 802.16-2004. Yet fixed WiMAX has not gone away. According to ADI's Thomas Gratzek, fixed WiMAX will definitely play a significant role going forward. He states that fixed WiMAX will comprise the bulk of the shipments in 2007 and probably 2008. It is an attractive modality for both Internet access and BWA. In addition, it will meet the needs of third-world as well as some first-world markets.
It also is easy to overlook the fact that WiMAX's effectiveness-mobile or fixed-will be lost in areas that need connections between devices in closer proximity, such as the home. Another broadband technology promises to fill this gap, however. Ultra Wideband (UWB) transmits information by generating radio energy at specific time instances over a large bandwidth. In other words, UWB allows large data files and digital multimedia to be wirelessly moved from one location to another in a home or office. Most UWB products on the market today are based on Wireless USB. For example, Alereon's (www.alereon.com) AL5000 platform was one of the first silicon products to be certified on WiMedia's (www.wimedia.org) UWB Common Radio Platform. The chip set covers the entire WiMedia spectrum from 3.1 to 10.6 GHz. In a recent demonstration of its solution in an 11 x 14-mm module, Alereon achieved application-level throughput over 200 Mb/s in Bandgroup 6. This achievement was later replicated in a 1/2-mini-card solution. The AL5000 family chip set integrates RF circuitry including power amplifier, low-noise amplifier (LNA), and transmit/receive (T/R) switch in addition to the media access controller (MAC) and baseband processor.
The Ripcord family from Staccato Communications (www.staccatocommunications.com) also has achieved WiMedia Platform Certification. The Ripcord 3500 series is implemented using 110-nm digital CMOS process technology. It is provided as a complete system-in-package (SiP) and wafer chip-scale package (WCSP). The silicon includes RF, digital baseband, MAC, memory, a 32-b RISC processor, encryption engine, and various I/O including USB 2.0 host, USB 2.0 device, and SDIO 1.1 device. Utilizing Staccato's Protocol Independent Kernel (PIK), which enables Certified Wireless USB, Ripcord can support Bluetooth v3.0, WiMedia IP, and new mobile services including mobile wireless video and personal-area social networking (PASN). Staccato also made news last month by closing an additional $17.5M in equity financing. This funding will be used to launch the company's first-generation, 110-nm single-chip solution. It also will continue the development of second-generation 65-nm single-chip, Certified Wireless USB, and Bluetooth v3.0 products.
The semiconductors from Artimi (www.artimi.com) promise to allow consumers to transfer photos, music, and video between consumer electronics devices at speeds of up to 480 Mb/s. The A-150 low-power, WiMedia MAC controller is suited for use in WiMedia Wireless USB, next-generation Bluetooth, and WiNet-based consumer-electronics devices. It is designed for embedded applications where high-speed bulk data transfer and synchronization is required, such as digital cameras and PDAs. In an LBGA package measuring just 10 x 10 mm, the A-150 includes an integrated MAC and a programmable applications processor for on-board processing in embedded applications. The A-150 partners with a WiMedia-compliant PHY to form a complete solution for wireless connectivity in consumer electronics devices.
The TT•1013 UWB solution from Focus Enhancements' (www.focussemi.com) is designed to be compliant with the WiMedia and ECMA-368/369 international standards. Thanks to its extended 3.1-to-7.4-GHz frequency range, the TT•1013 supports high data-rate UWB operations in both low and high bands as defined by the WiMedia and ECMA-368 international standards. This aspect enables the deployment of TT•1013-based products outside of the US without the use of mitigation techniques and time restrictions. The TT•1013 is actually the second-generation UWB solution of the Focus Enhancements' UWB radio platform. It hosts a full MAC, which is designed to be compliant with both Certified Wireless USB and WiMedia specifications. Through its distributed TDMA capabilities, the TT•1013 supports Quality-of-Service (QoS) sensitive applications, guaranteeing low latencies and high efficiency in the most critical of environments. The TT•1013 supports advanced security mechanisms based on AES-128 CCM cryptography. In addition, an advanced power-management engine is capable of dynamically selecting one of numerous power states during normal operations. In doing so, it ensures that the best tradeoff between performance and power consumption is always selected.
Although these products may support more basic applications like photo sharing right now, UWB is expected to eventually enable the high-speed transmission of video within the consumers' homes and offices. On a grander scale, mobile WiMAX will be making it possible to access higher-data-rate applications on the go. Thanks to broadband technologies, the wireless world is about to get a lot more entertaining.
