networkZONE Products for the week of September 15, 2003
Atheros Says…
Focus On Performance -- Atheros' Next-Gen Wi-Fi Chipsets
Double Range, Cut Power Consumption by 60 Percent
New Family Features Breakthrough eXtended Range Technology
and Industry's First Wake-on-Wireless and Wake-on-Theft Capabilities
Atheros Communications has announced two new chipsets featuring breakthrough
technologies to extend the range and reduce the power consumption of 802.11
wireless networks. When they are incorporated into WLAN devices, the chipsets
will offer end users extended range, longer battery life, and network management
tools that help reduce the cost of operating and owning wireless networks.
The Atheros chipsets use the company's eXtended Range (XR) technology to give Wi-Fi products twice the range of existing designs, and they have power-saving design improvements that reduce system power consumption by 60 percent. The chipsets are the first in the industry to provide important integrated wireless network management capabilities, including Wake-on-Wireless and Wake-on-Theft. These features enable users to remotely manage their wireless devices and receive an alert if they are stolen.
"We've incorporated important technical advances into our fourth-generation silicon to improve and drive the adoption of the next wave of wireless designs," said Craig Barratt, president and chief executive officer of Atheros. "Our new chipsets raise the bar on throughput, range, manageability and power consumption for the next generation of wireless LAN products."
eXtended Range Technology Doubles Wireless Range
Traditional Wi-Fi chipset architectures focus on maximizing throughput in
order to perform well in benchmarks and typical office environments. Such
designs typically don't perform well at long range. Atheros' new chipsets
feature a new baseband architecture that dramatically stretches the performance
of a WLAN by enabling long-range connections. The architecture delivers
receive sensitivities of up to -105dBm, over 20 dB better than the 802.11
specification.
Atheros' eXtended Range (XR) technology enables a single access point to cover multi-story brick or masonry homes and eliminates dead spots in corporate networks. It also enables Wireless Internet Service Providers to deploy public hot spots with coverage cells up to a kilometer wide. The eXtended Range operation is transparent to end users, and wireless products enabled with XR technology are fully interoperable with Wi-Fi compliant third party chipsets.
New Power Management Approach Improves Power Efficiency by 60 Percent
Conventional wisdom holds that 802.11b chipsets consume less power than
802.11g or 802.11a chipsets. Atheros' eXtended Range architecture debunks
that myth. It enables a new multi-phase approach to radio transmission and
power management that dramatically extends the battery life of mobile devices.
The new design limits the power consumption of different sections of the
wireless device according to the level of system activity. Compared to the
Intel Pro/Wireless 2100 802.11b devices used in Centrino systems, the power
consumption of the new Atheros chipsets during an active 802.11a/g transmission
is 20 percent lower, while during an 802.11a/g receive it's 30 percent lower.
The effect on battery life is even greater because these measurements compare
an 802.11a/g device operating at a 54 Mbps data rate with an 802.11b device
operating at 11 Mbps.
Especially significant is the performance of the new chipsets in idle mode, which accounts for most of the operating time of wireless LAN products. In idle mode, the power consumption of devices based on the new Atheros chipsets is about 95 percent lower than that of wireless devices used in Centrino systems.
Wake-on-Wireless and Wake-on-Theft Reduce Network Management Costs
Many companies rely on network management systems that remotely control
and administer desktop computers. Power consumption and design limitations
have traditionally prevented these systems from being used with wireless-enabled
laptop computers. Atheros' Wake-on-Wireless capability brings network management
to the Wi-Fi environment.
Enterprise management tools can administer wireless systems equipped with the new Atheros chipsets and take advantage of their remote wakeup and alert features just as if the wireless devices were on a wired network. The Wake-on-Wireless capability is compatible with existing network infrastructure equipment and industry standards for network remote wakeup functionality.
Atheros is also introducing a new Wake-on-Theft capability. This function can alert network administrators if a mobile device such as a laptop or PDA equipped with the new Atheros chipsets is removed from a company's facilities without authorization. The Wake-on-Theft function can also wake-up and raise an alarm on the mobile device, even if the device was powered off.
New chipsets available in volume
Atheros' fourth-generation AR5004 chipset family includes dual-band 802.11a/b/g
and single-band 802.11b/g designs. The chipsets are available now in volume.
The AR5004G supports 802.11b and 802.11g in the 2.4-GHz band from 2.300 to 2.500 GHz. The AR5004X adds support for 802.11a in the 5-GHz band from 4.900 to 5.850 GHz, thus enabling tri-mode or universal WLAN products. The AR5004X meets international requirements for WLAN operation based on the draft 802.11h and 802.11j standards. The only products to have CE marking for 5.47 GHz European operation and TELEC certified for 4.900 GHz Japan operation are based on Atheros chipsets. Both chipsets include support for emerging security standards such as Wi-Fi Protected Access (WPA) and draft 802.11i Advanced Encryption Standard (AES) with no performance reduction, and draft 802.11e Quality of Service enhancements. A single driver and firmware code base supports all Atheros chipsets, and provides both backward and forward compatibility with Atheros' previous and next-generation multi-standard designs.
New Chipsets Also Support Super G and Super A/G
Atheros' fourth-generation chipsets also feature the company's Super G and
Super A/G technology, which delivers 108Mbps data links with actual end
user TCP/IP throughput of up to 90Mbps in 802.11a/b/g, 802.11b/g and 802.11a
wireless networks. Super G and Super A/G are backward-compatible with conventional
802.11b, 802.11g and 802.11a products, and also support mixed-mode operation
with Atheros and third-party solutions in the same network. Super G and
Super A/G performance enhancement features were introduced with Atheros'
third-generation chipsets in May 2003.
analogZONE Says . . .
After being very unhappy with their early WLAN chips, I've been very pleased to see Atheros' apparent interest in balancing price and performance in their products. The previous generation of products which I reviewed this past spring indicated to me that they had realized that the future of Wi-Fi depended not on sacrificing everything to cut costs, but instead producing competitively-priced products that could deliver good range and data rates under real-world conditions. The new range extension and energy conservation features found in this next generation of products seems to continue their commitment to delivering ICs that will meet the growing consumer expectations for Wi-Fi performance.
As mentioned in the previous review, Atheros has also abandoned its earlier 5 GHz-only posture and gotten very aggressive in rolling out a line of very cost-conscious 2.4-GHz 802.11g products. In fact, Rick Bahr, Atheros' of VP Engineering, speculates that the difference in cost between "b" and "g" is closing so quickly that it could be as low as 10% by the end of the year. I think this is smart because there will most likely be some classes of wireless-enabled products which cannot justify the added cost of a dual-band link at this time.
They are introducing two new chipsets -- a dual-band tri-mode transceiver, and a 2.4 GHz-only b/g product. As mentioned earlier, both chipsets offer big improvements in range and battery life with an eye toward addressing some of the emerging markets such as handheld devices, multimedia gateways, and the new breed of "lightweight" access points that puts the intelligence for roaming management and association into a centralized server.
Atheros has put a big push on extending range -- with a goal of doubling indoor range, and close to tripling outdoor range at reasonable speeds -- all while holding their prices at or below current levels. After a long and candid heart-to-heart talk with Mr. Bahr about the techniques they used, I'm reasonably sure they will come close to meeting their ambitious performance goal. While I can't reveal everything I learned, I can say that Atheros is using several tricks, including an improved pilot tracking technique that uses all available data carriers as if they were additional pilots and does some clever symbol tracking to keep the radio actively tuned. They also tweaked their AGC circuit and used some additional techniques to improve coding gain.
The sum of all these improvements brings the receiver's sensitivity to -105 dB. That's 20 dB better than the IEEE standard. Hopefully, penny-pinching manufacturers and ODMs will not be tempted to use the margin from this extra sensitivity as a way to justify scrimping on antenna quality, PCB design, or otherwise deviate from the reference design.
Of course, at these gain levels there is a bunch more noise coming into your system that you have to contend with. That's why adaptive noise-filtering techniques were added to the chip. On the transmit side, they have developed some proprietary techniques to improve peak-average ratio to keep the PA closer to its most efficient region. This is even more important with the higher linearity demanded by the OFDM modulation used in the "g" and "a" specs.
The upshot of all this is that in a line-of-sight outdoor test, the Atheros chipset finally lost signal at 790 m, compared to around 250/265 m for Broadcom and Intel chips. This should also translate into very good indoor performance as well- something that's becoming increasingly important, especially in public infrastructure applications where reliable service is not an option.
Atheros is learning to "play well with others." Their XR technology is proprietary, but several of the range-extension features will improve link performance with any chipset on the other end. Most of the other XR functions lay dormant and only kick in when they hear another XR-enabled chipset, but don't interfere with other radios communicating on the channel. I asked Bahr what happens in a mixed-mode environment where an XR-enabled access point must talk to both XR and non-XR terminals at the same time. He claims that an Atheros-powered AP can receive or transmit XR and non-XR packets, back to back, and that the XR mechanism is not in any way modal. Apparently the AP does understand which stations are XR-capable in an early protocol exchange and just refrains from sending them XR-coded packets. To the best of my knowledge, their proprietary "SuperG" channel aggregation scheme also does not get in the way of normal operations, or affect interoperation with any Wi-Fi compliant product, although I would worry about enabling it in a public infrastructure situation.
Atheros has also devoted considerable energy to further improving power consumption. Among other things, they have shaved their idle power down to 4 mA, and it only needs to wake up briefly to listen for the control point's beacon unless it is actually transmitting or receiving. The improved sleep capability also includes a "wake on wireless" feature derived from "wake on LAN" function in wired Ethernet. It enables a sleeping node to stay associated with an AP, and allows remote management of embedded wireless nodes. If it catches on, it could be very helpful for wireless instrumentation systems and other unattended devices as well as more typical power-critical embedded applications like handhelds and cell phones. Their receive power, 284 mA, and transmit power, 370 mA are also some of the lowest I've seen in the industry. I was negligent in failing to ask whether this was for the 2.4 or 5-GHz radio, but will assume that these numbers reflect the lower frequency, and that 802.11a operation will draw at least a bit more power.
Atheros was cagey when it came to discussing pricing,
and would only say that the new products would "be priced at, or below
the cost of our 3rd-generation chips". Both chipsets will be shipping
in volume in September 2003.
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