FemtoDAB

June 24, 2009 in Applications, Consumer devices, Infrastructures, Services by Administrator | 4 comments

According to this article, Vodafone will be next week the first mobile network operator to launch a femtocell product in Europe:

“Looking like a home router, femtocells give 3G coverage indoors, and use home broadband to connect calls across the Internet to the mobile network.”

“… will be available on different price plans… Essentially, the femto is free to anyone on a £30 contract, and £5 otherwise – including dongle customers”

Femtocells are in fact compact devices (similar to Wi-Fi routers) that act as very low power cell phone base stations that can be installed in end-users premises. Typical cell phones can connect to them instead of the remote “high-power” towers operated by mobile network operators. Femtocells carry the usual communication services through standard Internet connections in homes and offices.

Key benefits to operators (O) and users (U):

  • Better in-building coverage (O, U)
  • Overall network infrastructure can eventually be operated at lower power levels (O)
  • Off-loading cellular networks (O)
  • MNOs can still charge service costs while using end-users resources (Internet) (O)
  • Use the mobile device at home at lower rates (U)
  • Does not need regular phone service at home anymore (O, U)

Could this femtocell approach be exploited in the context of digital broadcasting as well? At CRC, we have developed a compact software transmitter for DAB. This platform could be further integrated as a low-cost personal DAB transmitter or FemtoDAB cell!

Such a FemtoDAB approach could offer interesting benefits:

  • Better in-building coverage (O, U)
  • Overall network infrastructure can eventually be operated at lower power levels (O)
  • Outdoor, indoor roaming with the same device (broadcast enabled handhelds) (U)
  • Transmission of additional Internet radio content in the femtoDAB cell (U)

One of the challenges will be to make FemtoDAB more attractive than the Wi-Fi options.

Do you see any use cases for FemtoDAB?

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  1. MC’s avatar

    MC on June 25, 2009 at 3:52

    Interesting concept.

    However in the case of repeater, the issue would be to synchronize with outside network (SFN) or if it is on another frequency, to signal it so that handover can happen. (It would be easier if broadcasters would make their ETI feed available on the Internet)

    In the case of personal broadcasting, as added value compared to simple low power FM transmitter or wifi audio interfaces, I would see:
    - solve the difficulty sometime to find available frequency as FM band is full in some cities.
    - better audio quality (except for wifi audio interface where you can reach high audio quality)
    - simultaneous broadcasting of different content (playlist)
    - compared to wifi devices, no radiation from receiver. This may sound silly but I know more and more people that avoid wifi devices because of fear of radio waves, especially in bedrooms.

    The big issue will be the cost I guess….

  2. Administrator’s avatar

    Administrator on June 25, 2009 at 7:27

    Agreed, roaming would be an issue. Doing seamless transitions another. In the situation of roaming from DAB into a FemtoDAB, the DAB receiver would have to communicate with the “router” to tell it which station it is currently listening to. One way to do this with an hybrid DAB/GSM device would be to send information about current service tuned through the general Internet either with Wi-Fi or 3G

    Going the other way around, FemtoDAB to DAB would probably be easier in that the receiver would only have to look at the list of currently available stations in his geographical area to know if the one he’s listening to in the FemtoDAB is available for roaming. No communication would be required between the FemtoDAB router and the receiver.

    Avoiding electromagnetic emissions from the receiver is a very good point. Who needs an alarm clock radiating into your head all night long!

  3. Sylvie Noel’s avatar

    Sylvie Noel on September 9, 2009 at 13:13

    Question from a novice: could such an installation be used to give cell phone access to houses that are outside of the cell company’s coverage area?

  4. Richard M’s avatar

    Richard M on September 29, 2009 at 8:23

    A Femtocell like approach is currently used in Australia for retailers.
    In Australia certain types of low power transmitter devices are allowed for certain uses without requiring a specific licence.
    The regulator has declared that retailers of digital radio can use a low powered transmitter (about 1 mw amplifier power) at the point of sale to demonstrate DAB+ radios. These transmitters use a rooftop antenna to receive the signal, a very low power amplifier and transmit antenna inside the building. No echo cancellation is required as there is good isolation betwen the external roof top antenna and the indoor low power transmitter. Network synchronisation is not an issue as the delay through the simple amplifier is negligible.
    There is no technical reason why such a solution could not be deployed domestically – but that is currently not a legal option.

    Richard