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Wednesday, December 16, 2009

Bluetooth Low Energy Hype 3: Watch the Watch

Tomorrow, Dec 17, Bluetooth Low Energy will publish its first release. I was told that the v1.0 is only just up to the link layer. Those upper layer protocols, such as profiles are still under work and will not be released until Q2 of 2010. Somebody has already tried to downplay the importance of this release saying that with this partial release, no product can really be built in 2010.

I think after waiting for two years, those who are not patient have already used other competitive solutions out there; those who has been patient will be patient for another several months. And I believe those who are in the inner circle of BTLE SIG are developing products now based on beta profiles. So soon after the publication of profile, products, though not many, will be available in the market.

In this post, I will continue the BTLE hype series by looking into the BTLE networking deficiency. This is really an issue. 

Bluetooth is phone centric, so is BTLE. For those million or billions of forecast, more than 90% is the deployment on cell phones. But the addressed markets are different enough, that phone centric is no longer adequate.

I should elaborate a little bit. Both Bluetooth and BTLE fall in the personal area network category. The bottom line for a successful technology is to solve personal problems. For the use case of Bluetooth, the phone is the person, and the person is the phone. I mean it is rare that one person carry more than one phone, and the phone is rarely shared. So phone centric is people centric. But in the BTLE use case, the phone is likely only part of the person, and the people is more than just the phone. To understand this, think about the situation that you were running on a treadmill and your exercise data (heart rate, pace etc.) wound be preferred to be received by both your treadmill to display real time and your phone to record. In fact, you are very likely not carrying a phone but a watch when having the exercise.

To speak in a more technical language, the Bluetooth use case is an one-master star network, but such network will not be able to address the market that BTLE is intended to, where multiple masters and multiple slaves are usual.

The success of BTLE is measured not the installation base of cell phone where dual mode chips are used, but the proliferation of single mode chips to be used in sensor, watches and other "peripherals". These chip vendors will naturally go after the proven markets, or low-hanging fruits. What are they? the sports market that have been dominated by 5KHz analog (Polar), ANT and Nike+, and the remote control market in competition with RF4CE.

In the sports use case, predominately watch (or iPod) is the centric. In cases, like the threamill case above, there are multiple masters. But in the phone centric BTLE, watch is first the accessory ("peripheral") of phone, or in BTLE term the single mode slave of the dual mode master. This kind of slave watch can not be used to recieve heart rate and speeds independently and directly without a master phone. Unless a BTLE watch can change master / slave on the fly, the watch can either be the phone accessory to receive caller ID and short message, or the watch be the receiver and display of heart rate and othe sensors, but not both. Hang on a moment, what will it like when both a phone and a master watch are in a network?

Let's check the remote control market. In RF4CE, the remote is the master of the entire network. Equipments can share information each other, but has to be through the master remote control. For this use case, the focused RF4CE is sufficeint. Bluetooth Low Energy covets this market, but can BTLE copy the same model of RF4CE? No, the phone centric BTLE will not stop there. BTLE will definitely take the advantage of the phone and create the use cases such that you can use your phone to control TV and other things. However, how many phones will be in vicinity? will only one phone be allowed to control? When I control the TV using my phone, can you also control using your remote? BTLE will face another situation of multiple masters and multiple slaves situation in remote control market. Who will win the remote control market remains to be seen. If BTLE lose to RF4CE, I think it will partially caused by the mess created by itself.   

I think here I am creating several more BTLE varieties in addition to single mode and dual mode. The new varieties are singlle mode slave, single mode master, signle mode dual role, dual mode master, dual mode slave, dual mode dual role. Otherwise how can BTLE address the multiple master situation. Of course these vareites can not be teh solution. It is too complex. The single mode device has to be simple and the overal network has to be user friendly and offer common user experience.

I do not think there is a solution now, and I don't believe in the near future in BTLE ver 2.0, the solution will be cost effective either.

Zoom out a bit, in BTLE SIG, I can see the conflict of interests of the watch camp and the phone camp. So when we exlaim the birth of BTLE tomorrow, here is a cup of cold water to clear your head.

1 comment:

  1. I should first declare an interest - I work for CSR.. (I can’t see that the author has declared themselves or any interests?)

    Bluetooth low energy has been designed for user simplicity, and is not necessarily phone centric.

    There are only two modes of low energy operation (master and slave). Devices can only be a master or a slave (not both at once).

    Dual mode and single mode are a separate issue, and concern whether you need to connect to Bluetooth Classic devices for example for stereo audio streaming.

    In the gym example that you give, the watch can be the master collecting data. The sensors are slaves - the heart rate belt or foot pod.

    The only question is the running machine. In Bluetooth Low Energy this is performing the function of a remote display. It is a slave to the watch, and can be supplied with data.

    The role of the watch as master can be replaced by a phone for people who prefer to use an app on their phone. With Bluetooth low energy you can then stream your tunes to a wireless headset while you train, and also receive audio prompts and coaching.