Electronic Design

MIMO Chip Set Is Well "Received" In Wireless LANs

When it comes to boosting the range and data rate of wireless devices, there's a new player in town. MIMO, or multiple-input/
multiple-output, uses multiple antennas and receivers to achieve the benefits of spatial diversity (see "Smarter Antennas Breed Success In Wireless Arena," March 31, p. 48, ED Online 9987).

This technology does more than mitigate the multipath interference common to microwave transmissions. It also collects the multipath signals and adjusts them for improved reception. In addition, MIMO uses two or more transmitters to send data on two signals within the same bandwidth to boost speed.

Such capabilities propelled the creation of the AR5005VL chip set from Atheros Communications. Using phased-array beam forming, cyclic delay diversity, and optimal receive combining, this set delivers higher performance even when it's only used on one end of the wireless link. Enterprise access points, public hot spots, and home routers can then deliver higher speeds over longer ranges even with existing non-MIMO radios in laptops, PCs, and other embedded wireless local-area network (WLAN) products.

The AR5005VL chip set comes in 802.11g and 802.11a/g versions. When used at both ends of the wireless link, it delivers up to 50 Mbits/s of throughput. In mixed networks with different types of 802.11g interfaces, it boosts the data rate to 27 Mbits/s across a 3000-ft2 area by combining the multiple radios with new signal-processing capability.

Two AR5112 dual-band radio chips and the AR5513 multiradio smart antenna video processor chip are part of the set (see the figure). The AR5112 all-CMOS dual-band transceiver supports up to four antennas. The AR5513 includes a 180-MHz MIPS processor to form the transmit beam and perform the receive-combining algorithms.

The set provides all video-streaming capability over fast wireless links in new consumer electronics equipment. It features an integrated video/audio controller for MPEG and DMA acceleration. It also supports multiple DVD-quality connections or a combination of HDTV- and DVD-quality connections.

Other features include MPEG transport stream aggregation and MPEG encapsulation, hardware-accelerated AES and other types of encryption, and enhanced quality-of-service with packet jitter control. Atheros' Super AG mode, which delivers up to 108 Mbits/s in some WLAN links, is incorporated.

Available now, the a/g chip set sells for under $23 in 10,000-unit quantities. The g-only chip set costs less than $20 in the same quantities.

Atheros Communications Inc.

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