“A dropped stream is the nemesis of any regular Public Radio Tuner user. Nothing is worse than being caught up in a great public radio program and have it suddenly cut out….”

Some challenges can be expected:

• loss of signal while roaming from cell to cell. Networks are optimized for voice calls but not for data yet.
• minimal bitrate like 32 kbps is desirable but connection is still not guaranteed and sound quality is no great
• buffers have to be implemented in receiver to mitigate signal loss.

Results of a survey made by PC World suggest that 3G coverage may not be adequate for the delivery of sustained bitrates in major cities in USA. Like this table shows, networks speeds can be impressive but their reliability vary greatly so that live radio transmissions may be hard to achieve.

There is certainly a lot of room for experimentation here in this new area but I tend to believe that it could take a while before we see 3G replace true “physical layer” broadcast networks for live transmissions.

“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?

This could change thanks to so-called “in-car WiFi routers” which are designed to provide Internet access through 3G mobile telephony networks.

AutoNet Mobile offers such device and service combination:

we create a Wi-Fi hot spot that allows everyone in the car to connect multiple devices to the internet, in and around the car! it’s the next step in in-car entertainment and productvity. we make internet in your car easier than ever because we provide both the in-car router and the monthly service. our affordable monthly service plans start at only $29 per month.

This still represent an expensive proposition for radio though. One hour daily consumption of good quality Internet radio content could easily reach the 29$ 1Gb limit.