Wireless Systems Design

Chip-Set Architectures Widen WLAN's Scope

Armed With A New Baseband Technology, These Chip Sets Vow To Double Wi-Fi's Range And Cut Power Consumption By Up To 60%.

More often than not, Wi-Fi chip-set architectures concentrate on maximizing throughput. This focus serves as their prime means to perform well in benchmarks and typical office environments. Unfortunately, such architectures typically fail to perform at long range. This downside presents an obstacle for next-generation wireless devices, which will surely demand high throughput, range, and decreased power consumption.

Being acutely aware of this problem, Atheros Communications recently came to market with a family of fourth-generation Wireless Local Area Network (WLAN) chip sets. Known as AR5004, this chip-set family includes dual-band 802.11a/b/g and single-band 802.11b/g designs (see figure). Thanks to the company's eXtended Range (XR) technology, these chip sets double the range of existing Wi-Fi products. At the same time, they claim to reduce system power consumption by up to 60%.

The first two products in the AR5004 family are the AR5004X and AR5004G. The AR5004X is a dual-band 802.11a/b/g chip set. It promises to provide universal wireless connectivity to any 802.11 network anywhere in the world. The single-band AR5004G 802.11b/g chip set provides 802.11g functionality and performance. It is targeted for home and small-office users. It offers those users a flexible upgrade path for legacy 802.11b networks.

The AR5004G product supports the 802.11b and 802.11g standards in the 2.4-GHz band. That band ranges from 2.300 to 2.500 GHz. In contrast, the AR5004X adds support for the 802.11a standard. That standard inhabits the 5-GHz band, which spans 4.900 to 5.850 GHz. Because of its range of coverage, the AR5004X chip set enables tri-mode or universal WLAN products.

The AR5004X chip set also stands out for its global preparedness. It meets international requirements for WLAN operation based on the draft 802.11h and 802.11j standards. In addition, the AR5004G and AR5004X chip sets include support for emerging security standards, such as Wi-Fi Protected Access (WPA) and the draft 802.11i Advanced Encryption Standard (AES). They also support the draft 802.11e Quality of Service (QoS) enhancement.

At the heart of these two chip sets is a new baseband architecture. To enable long-range connections, it increases the performance of a WLAN. The architecture delivers receive sensitivities of up to −105 dBm. That figure is over 20 dB better than the sensitivities that are reached by the 802.11 specification.

The company's eXtended Range technology enables a single access point to cover multi-story brick or masonry homes. It also eliminates dead spots in corporate networks. In other words, XR technology keeps the 802.11 connection alive in places where conventional designs simply drop off.

For Wireless Internet Service Providers (WISPs), the XR technology allows public hot spots to be deployed with coverage cells that are up to a kilometer wide. The wireless products that are enabled with this technology are interoperable with Wi-Fi-compliant, third-party chip sets. More importantly, this multi-phase approach to radio transmission and power management extends the battery life of mobile devices. It limits the power consumption of the device's different sections according to the level of system activity.

To more deeply understand the AR5004G and AR5004X chip sets, one must look at their Super G and Super A/G technology. These technologies deliver 108-Mbps data links. The actual end-user TCP/IP throughput is up to 90 Mbps in 802.11a/b/g; 802.11b/g; and 802.11a wireless networks. In addition, both technologies are backward compatible with conventional 802.11b, 802.11g, and 802.11a products.

For more highlights of the AR5004 family, look to its Wake-on-Wireless and Wake-on-Theft capabilities. The Wake-on-Wireless capability is compatible with existing network-infrastructure equipment and industry standards for network remote-wakeup functionality. It permits the administration of any systems that are equipped with the new Atheros chip sets.

Of course, the Wake-on-Theft function also works solely with mobile devices that are equipped with the new Atheros chip sets. This function alerts network administrators if such a device is removed without authorization. The Wake-on-Theft function even works if the mobile device is powered off.

Both the AR5004G and AR5004X chip sets are shipping now. Contact Atheros Communications directly for specific pricing information.

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