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Airgo convinced laptop maker to use its chips: The Airgo third-generation chips have a finite lifetime, as they are not promised or expected to be upgradable to 802.11n. Airgo will have its own 802.11n chips within a few months. I can understand wanting greater range, but Asus laptop buyers will need to purchase 3rd-generation-based routers from Buffalo or NetGear to achieve higher speeds.
Added to the flurry of N-like news, Buffalo is shipping its fastest gateways: Buffalo’s gear uses 3rd-generation Airgo chips which are ostensibly not directly upgradable to 802.11n compatibility, although they may offer some interoperability that will boost them above 802.11g speeds when used with 802.11n gear. Airgo plans a 4th generation chipset for 802.11n compliance.
The gateway has an estimated street price of $150 and the notebook adapter, $100. The gateway uses a 10/100 Mbps switch, which will underperform the 100 Mbps-plus throughput that Airgo’s chips have been shown to be capable of on the wireless side.
EE Times offers a long tutorial in MIMO: This three-page online article spells out the various methods by which multiple antennas are used to achieve distance, robustness, and increase throughput by making use of multipath reflection, multiple spatial streams, and beam forming. For instance, MIMO could be used to increase distance through beam forming, which improves signal clarity to a particular receiver. This was the key technology underlying the Vivato switch, by the way.
Spatial multiplexing allows multiple streams of data to simultaneously use the same frequencies in the same space by following different spatial paths that a receiver can differentiate. Robustness can be achieved by sending the same data over multiple paths improving the chances of reception without error.
The writer concludes that MIMO will find its way into all RF designs because of the many ways in which it can improve the efficiency and utility of spectrum.
In all the discussion of 802.11n, the notion of using it for outdoor spaces as been little explored: 802.11n is an indoor specification, let’s face it. It achieves its potential rates (in the proposal accepted recently) through improvements to the MAC’s efficiency, RF upgrades, spatial multiplexing, and double-wide channels.
MAC efficiency could be a big improvement, in that the Media Access Control components deal with the fiddly parts of packaging data into frames (or removing them), error correction, and handling source and destination issues. Improvements to the MAC layer will help throughput regardless of other elements. Likewise, fixing radio frequency (RF) deficiencies in 802.11g and adding better characteristics will improve the quality of transmissions, too.
But when you get into the remaining two elements, there’s where the problem creeps in. Spatial multiplexing is one of the key advantages of multiple-in, multiple-out (MIMO) antennas. Using multipath reflection, a MIMO device—such as any future 802.11n radio—can produce multiple data streams that contains different information passing over the same frequencies. (They can also duplicate the same data for redundancy improving the fidelity of reception.)
In outdoor spaces, there isn’t enough multipath reflection close enough to a transmitter to provide that advantage. I’ll be curious whether a concrete canyon would work, say in downtown Manhattan, but wide open spaces won’t.
The double-wide channels, which will be 40 MHz wide instead of the normal 20 MHz for the 802.11 family, have a similar problem. In current thinking, 40 MHz can be used only if the airspace is clear. (Airgo’s early implementation of this is causing it some black eyes for neighborliness, although they have already stated some elements will be changed via firmware upgrades.)
In typical outdoor environments where using Wi-Fi would make sense, it is unlikely that any two adjacent channels would have no signal present.
The conclusion? The 200 Mbps to 600 Mbps possible in 802.11n will probably appear more like 40 to 50 Mbps of actual throughput for outdoor installations; indoors, 100 to 300 Mbps will certainly be achievable, however.
Tim Higgins posted a long review of NetGear’s RangeMax 240 which uses Airgo’s 3rd generation MIMO chips: He found that despite the promise by Airgo for this chipset to back off from using the equivalent of two Wi-Fi channels (40 MHz) when it detected other Wi-Fi networks on active channels nearby, current firmware fails at this task. He has the charts and graphs to show it. He also notes that Airgo and NetGear are aware of this problem.
He did find that the devices can deliver over 100 Mbps of real throughput, which is a first for any Wi-Fi-like device, and more significant still in a consumer-level product. (The NetGear has just 10/100 Ethernet switching, so it can’t deliver more than about 94 Mbps in Tim’s testing to a single port.)
If there are any other 802.11b/g networks in the vicinity, it makes no sense to install this generation of Airgo-based equipment until firmware problems are resolved. eWeek reached the same conclusion (less exhaustively but just as completely) two weeks ago.
Even when they are resolved, the Adaptive Channel Expansion (ACE) algorithm is somewhat different than what I heard from Airgo in Sept. 2005. Tim writes, “I should also note that Airgo told me that when it is working, it will take 5 to 10 minutes (!) to tune away from a neighboring WLAN that is detected after the RM240 completes its initial power-up sequence—if the RM240 sees “lots of continuous traffic” in the neighbor.”
In Sept., Airgo’s director of product marketing, Dave Borison, said that ACE didn’t create negative effects on neighborhing channels, and that it performs a frame-by-frame check on adjacent channels—but apparently, this just applies to b/g clients on the Airgo-based device’s network. Clearly, the current firmware in Tim Higgins testing doesn’t live up to that promise yet for adjacent networks.
Buffalo will ship 240 Mbps MIMO gateway, PC Card in February: It uses Airgo’s third-generation chips. The gateway will have a street price of $149; the adapter, $99.
NetGear previously announced its MIMO equipment in Nov.: They’re showing their Airgo-based gear at CES, too, but a shipping date doesn’t appear to be available. They were originally expecting to ship by Christmas.
Meanwhile, Atheros talks about the next-next-generation MIMO: The company is demonstrating a 3x3 array which will provide 300 Mbps of raw bandwidth, or about 25% more than Airgo’s gear. But we don’t know about the net throughput: Airgo says 100 Mbps for their system. (For more on what 3x3 means, see this Wireless Net DesignLine article that spells out why 3x3 might be the better route for 802.11n without dramatically increasing complexity or cost for chipmakers and gateway manufacturers.)
Tim Higgins rounds up most of the MIMO gateways and PC Cards out there for head-to-head, quantitative comparisons: HIs exhaustive testing and results analysis at Tom’s Networking reveals that Belkin’s Airgo implementation has the best consistent bandwidth performance, critical to gaming, voice over IP, and streaming media. (Linksys declined to provide equipment for testing, but it’s quite similar only more expensive.)
Interestingly, Higgins discovered that the newer Belkin equipment based on Airgo’s second-generation chips—cheaper and with one fewer receive channel than the first generation—provide equivalent or better consistent performance than the original Pre-N labeled devices. He recommends Belkin’s gear for its consistent performance.
For pure average throughput, Zyxel, D-Link, and TrendNet come in on the top, with both Belkin generations next in line alongside NetGear’s RangeMax. Higgins recommends D-Link, Zyxel, and TrendNet for best throughput.
He is down on the Super G mode from Atheros found in several devices he tested because its fastest mode (with or without MIMO options) requires a switch from two-channel to one-channel operation whenever “normal” 802.11b or g is detected. These changes in channel usage are what cause the great variations in consistent delivery of bits rather than overall throughput. In denser networking environments, like an apartment building or older residential neighborhood with small lots, the channel-bonding mode of Super G can barely add bits.
SMC is using Ralink’s chipsets for its new MIMO gear: The set of equipment includes a gateway, a PC Card, and a PCI Card for $140, $60, and $60, respectively. More devices in the line are due next year. The technology isn’t described in depth in this press release, but it appears to be promising better range and throughput but not increased throughput.
NetGear may have announced MIMO devices based on Airgo’s latest chip, but Linksys is shipping: Linksys brings its SRX400 gateway and PC Card to the market today through its online store; retailers will see products shortly. The devices are based on Airgo’s third-generation chipset, which offers raw speeds of up to 240 Mbps among devices using that silicon by dynamically using expanding to use 40 MHz or the equivalent of two channels on a packet-by-packet basis that avoids stepping on other transmissions in the same area. With 40 MHz and two spatially multiplexed channels, they can quadruple raw 802.11g speeds without losing compatibility.
The gateway’s retail price is $150; the PC Card, $100.
NetGear is the first to announce shipping dates for routers, cards based on Airgo’s 240 Mbps third-generation MIMO chips: The NetGear product line, called RangeMax 240, will start shipping “this holiday season” with the router and PC Card for retail prices of $199 and $129. The USB 2.0 adapter will ship next year for a price not mentioned.
The third-generation Airgo chips avoid colliding with other Wi-Fi networks by examining radio frequency usage dynamically. They can use multiple data streams as the frequency space is available rather than just dropping to a lower speed for a few minutes and testing whether the coast is clear. This improves overall throughput even in Wi-Fi-filled environments.
The net throughput should exceed 100 Mbps Ethernet speeds when all RangeMax 240 gear is used. The devices are backwards compatible with previous generation Airgo chips and with 802.11b and 802.11g devices.
Azimuth Systems releases MIMO emulator to help test new devices: A robust testing suite can help manufacturers tweak designs before they reach production. Azimuth has added MIMO hardware and capabilities to its product suite so that engineers can examine interference and propagation issues in environments that emulate real-world use.
Airgo announced its next-generation MIMO chips today: Airgo’s newest entry in the MIMO field will hit 240 Mbps of raw throughput when communicating among identical devices. The new chips are backwards compatible with 802.11a, b, and g, and previous Airgo-based devices. Actual throughput should be about 100 Mbps versus about 20 Mbps for plain 802.11g and 30 to 40 Mbps with various extensions and antenna technologies.
Airgo’s director of product marketing Dave Borison said in an interview that the third-generation chips will help wireless enter the consumer-electronics market for streaming video around the house. “These products will literally support multiple streams of HD [high-definition television] over an entire home,” Borison said. The higher speed also comes with a maintenance of higher speeds at greater distances than existing gear of any kind.
The new chips employ 40 megahertz (MHz) wide channels rather than the 20 MHz used for 802.11 standards. Unlike Atheros Turbo mode in Super G, the Airgo chips expand spectrum to adjacent channels, and make that decision by monitoring spectrum on a frame-by-frame basis. Older devices receive 20 MHz single-channel transmissions; compatible newer adapters accept 40 MHz as available using what they call Adaptive Channel Expansion. “They don’t create negative effects on” neighboring channels Borison said.
The 240 Mbps rate doesn’t include compression; it’s the raw symbol rate passed through the devices, Borison said. As with earlier Airgo gear, both 2.4 GHz and 5 GHz are supported with 802.11a, b, and g compatibility.
While Airgo isn’t producing equipment that matches point for point either of the competing proposals in Task Group N (802.11n), some aspects of these new chips parallel general trends in the group.
Borison said Airgo is confident that their technical lead will continue for some time. “We’ve now got four or five years plus, three generations of commercially available silicon, ahead of any of our competitors that haven’t even launched their first generation,” he said. The new chips are in sampling now with manufacturers.
Other coverage: Reuters notes that the new chips will cost less than the current generation.
Mobile Pipeline loves Belkin’s G+MIMO gear: The newer, cheaper MIMO hardware from Belkin—based on Airgo’s second-generation MIMO chips—scores high in the analysis of this reviewer. Belkin downplayed this device in comparison with its so-called Pre-N (first-generation Airgo-based) equipment, but the reviewer finds that it performs as well or better. He recommends buying the $100 router but holding off on the PC Card to get enough of an advantage.
Linksys announced today it was shipping its version of this router, the WRT54GX2, with a street price of about $100.
Airgo’s True G gear will be less than $100; sports two antennas: True G is Airgo’s alternative to True MIMO, which employs multiple simultaneous data streams over different paths when endpoints are using Airgo’s technology. True G only has two antennas to True MIMO’s three—as sold by Linksys, Belkin, and others. A company spokesperson explained that the reduction in cost was achieved through fewer antennas and a lower component count.
Airgo has been frustrated in its attempts to capitalize on MIMO as a term that they “own”: True MIMO is a trademark, but Airgo also wants MIMO to refer only to those devices that use spatial multiplexing. (Some dispute Airgo’s founders position as the inventors of MIMO, too, citing earlier papers, but the founders’ early work in the field is what’s been instantiated as product by them.)
True AG chipsets will also be available for 802.11a and g range extension. Both True G and AG will have two receive and two transmit antennas; the True MIMO devices have three receive and two transmit antennas.
According to this article, Airgo expects street prices of gear based on their chips to drop to $129 to $149 for True MIMO and $69 to $99 for a router for True G. True AG will be slightly more expensive.
Extremely clear, detailed article from AP on the non-standards mess around MIMO: Matthew Fordahl’s superb piece examines the nomenclature problem, the process of standards’ development, certification issues, and consumer confusion.
Airgo chips will power embedded MIMO in Samsung laptop: This is a first—a manufacturer building a MIMO adapter right into a laptop. But it’s an interesting option because, for competitive reasons, they can’t price the laptop above similar laptops unless MIMO is a selling point. Thus it obviates some of the concerns with separately purchasing a MIMO adapter due to cost or future compatibility.
Very few internal laptop adapters can be updated anyway, so you can’t argue convincingly that having an early MIMO device that’s backwards compatible and offers greater range even without a MIMO gateway is a downside for a purchaser.
I review NetGear’s RangeMax MIMO device at Mobile Pipeline: I found its range extraordinary and worth the price. It sits in a middle ground in cost and feature claims between the Airgo-based Linksys, Belkin, and Buffalo gear and plain old 802.11g.
It calls itself MIMO, and I can’t really say that it meets the spec in that MIMO requires spatial multiplexing. Or so the inventors of MIMO—founders of Airgo—would say. (Nanotech used to mean little machines but now means anything small, too.)
Jungo will produce reference designs ready to go for Airgo’s MIMO chips: Reference designs are licensed by manufacturers who add their own case designs and customization to the software featureset and then have them manufactured on demand. This is typically how most major Wi-Fi and Ethernet equipment comes to market. A relatively small percentage is developed in house.
Jungo uses embedded Linux and provides an essentially turnkey system for manufacturers who may add a little secret sauce in the form of a custom configuration wizard and extensions to integrate with other products in their network family. The OEM (original equipment manufacturer) as the retail brands are known in this case handle inventory, sales channels, outsource production, and technical support.
JiWire offers a long review of Linksys’s MIMO router: They find the Linksys SRX is the best-performing MIMO router they’ve tested so far but would like setup improved and the price dropped.
Buffalo Technology uses Airgo chips to enter the MIMO market: Buffalo will ship a gateway and PC Card in mid-May similar to those offered by Belkin and Linksys. The retail price is $189 and $119, respectively.
Tim Higgins of Tom’s Networking offers his exhaustive look at the NetGear RangeMax Wireless Router: This device uses Atheros’s Super G technology combined with Video54’s multiple antenna approach. The folks at Airgo say that Video54’s MIMO isn’t MIMO because it doesn’t support spatial multiplexing (multiple signals taking different paths over the same frequencies). Video54 says multiple antennas are multiple antennas; they’re using a phase-array approach per packet in which each packet can be sent through a different antenna combination. The device has a street price of just $118, far below its “true MIMO” competitors.
Higgins thinks that the device delivers on some but not all of its claims, and that because four different technologies are involved (three from Atheros then Video54 on top) he has some issues with the simplicity of it, too. He doesn’t know which technologies need to be turned on, off, or changed in order to achieve the best results with that combination. That’s a key advantage for the True MIMO line of products using Airgo chips: it’s essentially one technology that wraps around all these ideas while delivering better results.
MIMO is hitting the market, but what’s the future of the products shipping now?: This piece I wrote for Mobile Pipeline provides an overview of MIMO technology and some of the issues that will face buyers of technology today—will that gateway they bought work tomorrow? Well, sure. But you won’t be able to use the fastest versions of “true MIMO” as backwards compatible versions of future MIMO, almost certainly.
Remarkably, NewsFactor Network has a similar story with a bit of a different tack: that author focuses on spatial multiplexing and its ability to increase the effective carrying capacity of a chunk of spectrum. Atheros’s two radio, four antenna system transmits the same data over both radios; Airgo’s MIMO sends different data over each radio sending signals across different paths. Atheros increases range; Airgo increases data rate and range.
USA Today columnist calls MIMO-equipped gateways out of the ballpark: Despite problems he had using a Linksys WRT54GX’s flash settings, Edward Baig was impressed with the results of MIMO when using just a MIMO adapter or just a MIMO gateway, a common sentiment. He tested a variety of real-world conditions and found that even the worst cases were far better than plain 802.11g. Price is an issue, but he doesn’t stress it as performance obviously exceeded his expectations.
Craig Mathias of the Farpoint Group runs down the state of MIMO and its future: MIMO’s current technology appears in products from four vendors, two of which are following a multiple antenna strategy that the other two (and their chip supplier Airgo) say flatly isn’t MIMO. Airgo, Linksys, and Belkin would argue that spatial multiplexing, or sending data over the same frequencies through different paths is MIMO while the others use beamforming and phase array techniques.
Mathias recommends MIMO unhesitatingly after performing tests with Belkin’s Pre-N gear and a variety of 802.11g adapters and gateways. He points out rightly that for distance and throughput, MIMO beats cheaper 802.11g devices because of the complexity—and might be cheaper depending on how many 802.11g devices you’d have to put together to reach the same results.