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Back to Sub-1GHz ?

From DASH7 Wireless Sensor Networking Blog

It is a great for the success of wireless sensor networks that people are starting to realize how hopeless the 2.4 GHz band has become, but it is not enough to merely embrace “Sub-1GHz.”  … 433 MHz has greater worldwide appeal, support by the single most import entity for emerging IT standards (the US DoD) and, also importantly, it appeals especially to markets that tend to embrace new technologies a lot faster than does the US private sector.

Technically sound or more like plain marketing?

Full text of the post here

Comments on: "Back to Sub-1GHz ?" (4)

  1. Bill Owens said:

    But. . . it’s only about as fast as a dial modem, and if you want to build a DASH7 device, you have to buy a license. That doesn’t sound particularly appealing to me, unless I’m missing something.

  2. Both technically sound and marketing. Range (path loss) is a function of the inverse wavelength^2 so lower frequencies will give you longer range. However at 433 MHz, you have much longer antennas and fewer channels to move to. Also, since the bitrate is 10x slower than 802.15.4 the argument of lower power is a bit of a stretch. For the same amount of data, Dash7 would need to keep the radio on 10x longer. Hence, its both technically sound and marketing hype.

  3. “It is a great for the success of wireless sensor networks that people are starting to realize how hopeless the 2.4 GHz band has become” … is this really what people should realize? And is looking for new bands the real solution to this problem? I don’t think that moving to sub 1GHz would be such a smart move: beside lower data rate and bigger antennas (already mentioned), lower path loss surely means longer communication ranges but also higher interference. Looking for new bands would just be a miopic solution that would only postpone the real problem.

  4. Marketing aside, each band have different propagation behavior, respective standards have different features, etc. Thus, i agree, it depends on the application needs. However, the important design metric for low power radios is the communication energy efficiency (in Energy/bit), that is incluiding the *power consumption of the chip* (in 802.15.4 implementations this is at least one order of magnitude higher than RF Tx power, also important in Rx mode due to DSSS de-spreading — 50 mW for CC2420–, probably more significant than antenna efficiency constrains). The trend is that most efficient radios operate at higher frequencies and display higher spatial capacity in kbps/m^2.

    Indeed, if ubiquitous low power wireless takes off all bands will ultimately experience congestion, spaces will be jam-packed with devices which may suffer from and cause interference to each others. And, therefore, further research is needed to design reliable protocols capable of avoiding interference among different standardized networks and increasingly deal with collocation issues.

    So, yes, i find the statements on that post to be market driven :-/

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