Wireless Systems Design

Single Chip Set Supports Multiple Wi-Fi Versions

Multi-standard, multi-band mobile devices are the products of the future. The IEEE 802.11 wireless local-area-network (WLAN) specification family is a prime example of this trend. Three variations of 802.11 protocols exist at the moment: a, b, and g. A fourth one, "n," is due out in the next couple of years. Most home wireless networks use 802.11b, while many businesses opt for the high bandwidth afforded by 802.11a. A migration path to high data rates is provided by the most recent addition, 802.11g.

With a sizeable market base already established for 802.11b and 802.11a, it's hardly surprising that vendors are beginning to offer devices and applications that cover all variations. One example is Texas Instruments' (TI's) new wONE software package. On a single chip set, it supports the simultaneous use of either 802.11a and 802.11g or 802.11b and 802.11g networks. In contrast, other dual-band devices use multiple chips to support the different standard variations. TI believes that overall product cost savings can be realized by supporting all of the protocols on a single chip.

The wONE universal-router-software technology aims to provide the affordable multimedia home networking of video, audio, and imaging (802.11a) as well as data (802.11b/g). These wireless networks should suffer minimal interference or performance degradation, as 802.11g and 802.11a operation are delivered simultaneously from a single chip set (CPU, MAC, baseband, and radio-frequency (RF) functions).

The benefits of this dual-band router are twofold: cost and compatibility. Because wONE is a software-based application, manufacturers should be capable of offering routers to consumers at a much more affordable price (as compared to competing multichip solutions). On the consumer side, users should be able to protect their existing 802.11b or 802.11g devices while gaining a migration path to future compatible network applications that use 802.11a.

The wONE router software runs on TI's MAC/baseband processors with the company's CPU, 802.11a/b/g transceiver, and 802.11a/b/g RF front ends. It is part of the company's access-point (AP) design kit, which was created to help quicken the development of 802.11 platforms. wONE is said to be fully interoperable with all 802.11a, b, and g products. Consumers can utilize a web-based GUI to configure router operation in 802.11b/g-only, 802.11a-only, or 802.11a/b/g modes.

Using adaptive time-domain switching technology, wONE enables two separate queues to control traffic. This function gives users concurrent and uninterrupted 802.11a, b, and g access. Algorithms adjust for bandwidth allocation across the number of 802.11a, b, or g clients. They can then ensure optimal performance for every user. The company notes, however, that users will take a performance hit when running two networks simultaneously.

Users can expect around 20-Mbps bandwidth when connected to either an 802.11a or 802.11g device. When the router is simultaneously supporting clients on both networking technologies, the bandwidth may drop to around 10 Mbps per user. But even this reduced bandwidth should be enough for today's consumer and small-business wireless applications. Most cable or digital-subscriber-line (DSL) Internet connections only provide 1 to 2 Mbps of bandwidth.

The wONE router is currently available as part of Texas Instruments´ APDK 5.1. For pricing information, please visit the TI web site.

Texas Instruments, Inc.
2500 TI Blvd., Dallas, TX 75243-4136; (800) 336-5236, www.ti.com.

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