As standards wars rage on in 802.11 wireless local-area networks, the Proxim Harmony 802.11a card shows the promise of a cost-effective wireless bandwidth adequate for video and data by cranking up wireless data rates to a theoretical 54 Mbits/second and beyond, although actual throughput is lower. The device also reveals how much potential for silicon integration still lies ahead for 802.11 cards-and just how inexpensive those adapters could soon become.
Proxim's 802.11a Harmony is packed in a Type II PC-card format that consists of a single pcb sandwiched between plastic and stainless-steel front and back covers. A four-layer circuit board measuring 4.8 x 11.5 cm supports an all-surface-mount component set exclusively on the topside. Approximately one-fourth of the board is devoted to the built-in diversity antenna and its ground plane. The diversity antenna elements are simple disk-shaped metal stampings that account for the bulge in the external package opposite the standard 68-pin PC-card connector.
Internal electronics reflect the high level of integration already achieved in 802.11a wireless chip sets. Key to the Harmony design is the Atheros AR5000 chip set, which divides 802.11a silicon into two components: an AR5110 baseband/media-access control chip and the AR5210 so-called radio-on-a-chip.
Both Atheros components are implemented in standard CMOS technology, despite the 5-GHz carrier frequency for the 802.11a standard. The two-chip set provides baseband processing, A/D and D/A conversion, protocol and security algorithms, interface with the host, front-end low-noise amplifier receiver, transmitting power amplifier, up- and downconversion, and synthesizer circuitry. With the exception of a small Atmel E2PROM, the chip set contains its own memory and controller. What appears to be a power management chip from Volterra rounds out the total of a four-IC component set.
While the retail price of $120 to $170 for 802.11a cards from Proxim and others is far from cheap, our manufacturing-cost estimates peg the cost-of-goods-sold for the Proxim card at $30. Development costs, overhead and profit are not reflected in that figure but with continued margin erosion and component set simplification, the stage is set for inexpensive high-bandwidth WLAN solutions.
Once the dust settles on standards-and struggles with range, penetration and security are overcome-expect WLAN solutions to offer untethered options for surfing the Net, watching TV or even both.
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DAVID CAREY IS CHIEF EXECUTIVE OFFICER OF PORTELLIGENT (WWW.TEARDOWN.COM). THE AUSTIN, TEXAS, COMPANY PRODUCES REPORTS AND RESEARCH ON MOBILE, WIRELESS AND PERSONAL ELECTRONICS SYSTEMS.
