A while back I wrote about Ozmo, a company that plans to replace Bluetooth with Wi-Fi in certain applications.

Ozmo’s pitch is that their special version of Wi-Fi is faster, less prone to interference, cheaper and more power efficient than Bluetooth. Though slow for Wi-Fi, Ozmo’s data rate of 9 Mbps is way better than the 3 Mbps of Bluetooth 2.1 plus EDR. Concerning interference, Bluetooth transmissions are in the same 2.4 GHz frequency range as Wi-Fi, so careful engineering is always needed for coexistence; but coexistence is not an issue for Ozmo, because it is a flavor of Wi-Fi. The lower-cost part of the story is that while an Ozmo chip for a peripheral is roughly the same price as a Bluetooth chip, it saves the need for a Bluetooth chip in the host device. So if Ozmo’s claims of double the battery life of Bluetooth turn out to be valid when tested, the pitch holds water.

Bluetooth is unshakably incumbent in the billion-unit-per-year mobile phone market; most phones are now shipping with Bluetooth. But in laptops the Bluetooth attach rate is still well under 50%, while the Wi-Fi attach rate is close to 100%. So it makes sense that Ozmo is focusing initially on the computer market. Ozmo enables a laptop to use wireless peripherals like mice, keyboards, game controllers and headsets with a software modification to the Wi-Fi rather than having to include a USB wireless receiver in the package.

Ozmo is also focusing on the Consumer Electronics market, where Wi-Fi is gaining traction, and where the ability to support wireless remotes and similar peripherals can be added ‘free of charge’ to a device that already has Wi-Fi.

Since this is a compelling proposition, OEMs in these markets are likely to fall into line relatively easily, and indeed Ozmo has already secured the support of the biggest fish in the PC pond, Intel.

It may be a harder sell to the peripheral manufacturers. For them it’s not just a software upgrade. It is a new product line, one that depends on a single source for a key component and that sells into a currently non-existent base of host devices.

On the other hand, the peripheral device manufacturers may not be oposed to a new product line - they already have a plethora of products, using a variety of connectivity technologies including proprietary ones. Adding another one may not be too arduous, especially if it removes the need for a USB part. Ozmo could overcome the non-existent base issue by supplying, or convincing Intel and the other PC Wi-Fi chip vendors to supply, upgraded drivers for legacy Wi-Fi devices.

I already wrote about how Bluetooth is specifying Wi-Fi for its high bandwidth transport in a future version. Now there’s another interesting Bluetooth/Wi-Fi juxtaposition.

You may remember that last year Bluetooth subsumed WiBree as an ultra low power consumption variant. Now something analogous is happening in Wi-Fi, where a startup called Ozmo has come up with an ultra low power variation of Wi-Fi, which it is pitching as a substitute for Bluetooth.

Ozmo is not the first to propose this. Nanoradio claims that its implementation of Wi-Fi consumes way less power than Bluetooth, and they have a reference design for a Wi-Fi headset to demo the concept. Atheros has also recently announced a low-power Wi-Fi chip - so low that they claim “near zero” stand-by power consumption.

So Ozmo may not be so radical in its low-power claims, but it also claims low-cost. The Ozmo chip is priced the same as Bluetooth chips, which Ozmo estimates are between 1/4 and 1/3 the cost of Wi-Fi chips.

The Atheros and Nanoradio chips are full implementations of Wi-Fi; Ozmo’s is, according to this EETimes article, a “stripped down” version. This may mean that it is a non-standard version, in which case it would need a new certification program from the Wi-Fi Alliance - not a major obstacle, I presume, in view of Intel’s strong support for Ozmo.

So why would anybody want a version of Wi-Fi to substitute for Bluetooth, when we already have Bluetooth? Well, while most phones come with Bluetooth these days, in the PC world Wi-Fi is far more common than Bluetooth. So for peripherals designed exclusively for PCs, like mice and keyboards, Wi-Fi makes more sense than Bluetooth simply on the grounds of out-of-the-box compatibility. Add the technical benefits, like coexistence (Bluetooth and Wi-Fi tend to step on each others’ toes) and superior performance (Ozmo claims double the battery life in similar applications to Bluetooth), and it seems like a no-brainer.

The factors that could cause it to fail are ease of use and price. The setup of the peripherals with the PC must be completely automatic, and the operation of the devices must be flawless. Peripheral manufacturers must produce Wi-Fi versions of all their wireless products, and price them the same as their Bluetooth versions. The Wi-Fi drivers on the PC side will have to be modified in order to permit the PC Wi-Fi to communicate simultaneously with access points and peripherals. This is being done anyway by Intel, in a project called “Cliffside.”

All these impediments are mitigated considerably by Intel’s involvement. Intel makes most of the Wi-Fi chips in PCs, and presumably these chips will support the Ozmo products. With this assurance, peripheral manufacturers will feel comfortable going ahead with Ozmo-powered products.

The Bluetooth SIG put out a press release the other day saying that by mid-2009 a specification that includes Wi-Fi as an “alternate MAC/PHY” will be released.

This is the relevant part of the release:

What we’re doing is taking classic Bluetooth connections – using Bluetooth protocols, profiles, security and other architectural elements – and allowing it to jump on top of the already present 802.11 radio, when necessary, to send bulky entertainment data, faster. When the speed of 802.11 is overkill, the connection returns to normal operation on a Bluetooth radio for optimal power management and performance.

So this innovation specifies an interface above the Bluetooth MAC layer that enables Bluetooth session data to flow through a Wi-Fi radio instead of a Bluetooth one.

The press release says that the Alternate MAC/PHY will be used to do things like:

Wirelessly bulk synchronize music libraries between PC and MP3 player.
Bulk download photos to a printer or PC.
Send video files from camera or phone to computer or television.

But the new specification will only be useful in devices that already have both Wi-Fi and Bluetooth, and Wi-Fi can do these things without any assistance from Bluetooth. So the increment in value may be small; but Bluetooth can still bring something to the table. According to Wikipedia,

The Bluetooth Radio will still be used for device discovery, initial connection and profile configuration, however when lots of data needs to be sent, the high speed alternate MAC PHY’s will be used to transport the data.

It seems oddly limiting not to go the whole way, and enable Bluetooth applications to run on top of Wi-Fi even when there is no Bluetooth radio.

CSR announced their Bluecore 6 chip today. It will ship in production volumes in January 2008. CSR claims a more robust connection - with increased transmit power and receive sensitivity. CSR also claims a breakthrough in sound quality, achieved by going from a Continuous Variable Slope Delta (CVSD) codec to Adaptive Differential Pulse Code Modulation (ADPCM). This enables packet retransmission and a halving of transmission bandwidth. The reduced bandwidth requirement results in a reduction in power consumption, and the ADPCM codec yields a MOS of 4.14 compared with a maximum of 2.41 for CVSD.

This is a welcome change, but doesn’t really go far enough. What’s needed is a wideband codec like AMR-WB to yield better-than-toll quality sound. While this would be redundant in a regular cell phone - ADPCM is more than adequate to carry a signal that has been encoded in GSM - it would make a huge difference in dual-mode phones carrying Voice over Wi-Fi.

I went to an Apple store today, to buy an iPhone Bluetooth headset. I asked the clerk how the iPhone is selling, and he said “Steady, to both business users and consumers.” I came back to my desk to find a press release from iSuppli saying that the iPhone was the best selling smartphone in the US in July, with 1.8% of the overall cell phone market.

The iPhone Bluetooth headset comes in a box about the same size as the iPhone’s box. As usual with Apple, the box and all its contents are seductively designed, a pleasure to unpack and examine. The headset itself is tiny, but it comes with two USB connectors, one a nice docking station for the phone plus the headset, and one a traveling cable for both the phone and the headset.

One benefit of these dual connectors is pairing. To pair the devices simply plug them both in at the same time. That’s all. It worked for me. Another nice touch is the charging progress indicator that appears on the screen of the iPhone. It shows the battery status of both the headset and the phone.

The headset comes pre-charged; it was only plugged in to the dock for a couple of minutes before the light went green. Even plugging it in brought a little lift of the spirit, as I discovered that it uses the same magnetic engagement technology as the MacBook power connector.

What a disappointment when I made a call, though! There was a lot of static and a sound like running water at both ends of the connection. This is par for the course in my experience of Bluetooth headsets (there are half a dozen discards in my desk drawer), but still not acceptable. The headset was about 3 feet from the phone. There are several Wi-Fi transmitters in my office, but Bluetooth is supposed to be immune from this kind of interference due to its adaptive frequency hopping, which is supposed to learn which frequencies are conflicting and avoid them. ** Update: on subsequent calls I didn’t experience the same degree of impairment, so this initial experience may have been anomalous. The call quality on most calls appears to be acceptable. Even better, this is the first in-ear headset I have used that is so comfortable that I forget I am wearing it. This is a breakthrough. But now that it’s in my ear all the time I am beginning to be concerned about battery life. **

About a billion cell phones were sold in 2006, of which about 50% had Bluetooth capability. About 100 million bluetooth headsets were sold in 2006. Although 100 million of anything is a lot, it is only a 10% attach rate for headsets to phones. I believe the attach rate would be higher if the comfort, sound quality and ease of use were improved.

A strange omission in the iPhone Bluetooth headset is the apparent lack of support for playing iPod content through it. While it may make sense to think that music listeners must have stereo, not every MP3 is music. I play a lot of saved NPR clips through my iPhone, and the headset wires are constantly getting tangled up. Balanced against this inconvenience I would be quite satisfied with monaural playback of this content through a Bluetooth headset. It seems high-handed to deny this option to those who might find it useful. Perhaps this design decision has something to do with battery life.

An earlier post in this blog discussing dual mode phones mentions the trough of disillusionment as a part of the technical product hype cycle. This article from 2002 gives an amusing view of Bluetooth from the bottom of that trough; industry experts warn that it could be 2012 before Bluetooth is pervasive. It turns out that in 2007 Bluetooth will be in almost half the handsets sold. In retrospect it seems so inevitable.

The article covered its bets in the final paragraph, quoting Instat predicting 690 million Bluetooth chipsets to be shipped in 2006. Actually, by the end of 2006 the run rate was 12 million units a week. Considering it was a four year out prediction Instat’s accuracy was remarkably good.