Electronic Design

Communications> Multimode Wireless Networking Will Drive Seamless High-Speed Connectivity

This year will mark the initial deployment of multimode 802.11a+b+g wireless networking solutions, quickly making discussions of wireless networking standards irrelevant due to seamless connectivity. Until now, the three wireless networking standards have met with varied market reception: 802.11b is currently the most widely deployed solution with data rates of 11 Mbits/s; 802.11g delivers speeds of up to 54 Mbits/s; and 802.11a matches this faster speed using a different frequency spectrum (5.2 GHz versus 2.4 GHz for "b" and "g"), seeing only modest implementations.

Multimode products deliver the best user experience and performance by providing access across disparate networks through dynamic selection of a, b, or g, depending on system capabilities, channel loads, and type of information. Multimode solutions marry the respective strengths of 802.11a and g networks, delivering the best possible wireless connection and empowering high-speed, high-bandwidth multimedia applications.

To boost 802.11 data rates to 54 Mbits/s, robust orthogonal frequency-division multiplexing (OFDM) is used in the 802.11a and 802.11g standards to increase spectral efficiency and allow greater throughput in the channel. These standards can easily coexist in multimode solutions because they occupy different areas of the spectrum.

Capitalizing on wireless architecture designs that include dual-band radio implementations for OFDM-based 11a and 11g, multimode chip sets can also bring significant cost efficiencies through reduced bill-of-materials and small die size. Though multimode chip designs may initially show cost deltas to 802.11g-only solutions, this will quickly diminish. As a result, Wi-Fi product makers can develop multimode solutions at or below the cost of g-only. The choice for multimode is obvious.

The 2.4-GHz frequency band for 802.11b/g networks limits the number of available channels, allowing only three to be used for simultaneous transmissions at any given time. This means that 802.11g-enabled hot spots can be serviced, for example, by only three network access providers. Yet the 5.2-GHz spectrum allows for up to 18 independent channels, providing six times more bandwidth in the air. Multimode, then, affords greater opportunities for increased wireless services. For instance, it offers a competitive selection of network operators in a given hot spot. This facilitates high-speed connectivity to multiple apartments and delivers high-speed streaming video over dedicated channels.

The unlicensed 2.4-GHz frequency band is home to multiple wireless devices and applications, like cordless phones, microwaves, and Bluetooth, making 5.2-GHz Wi-Fi connectivity a favorable alternative to congested networks. Conversely, 802.11a network's limited indoor range makes 802.11b/g connectivity preferable for transmitting signals across greater distances and through walls in detached homes. Again, multimode's ability to dynamically select frequency spectrum offers users the right connection in the right environment.

The expectation of pervasive communication and information access without regard for the means is the fundamental benefit of multimode wireless networking. Retail advertisements, corporate IT discussions, and public hot spots detailing 802.11a, 802.11b, and 802.11g products and services will soon evolve to simply Wi-Fi.

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