Broadcasted radio consumes much less power than streamed radio.
Sometimes even a non-scientist like me feel like doing some experimentation. To find out how long a mobile phone battery will last if I want to listen to the radio via streaming vs. via broadcasting. The background? Harald A. Nissen, a politician representing “The Environment Party The Greens” (Miljøpartiet dei grøne) claims in Dagens Næringsliv, a Norwegian business daily, that DAB is not environmentally friendly and calls for distribution via DAB to be replaced by distribution via mobile internet.
This may sound good and plausible to potential voters, Norway’s election is on September 9, but let us look at some background material.
A report from Dutch independent research institute TNO states that in order to cover all of Holland, a mere 31,000 square kilometers, you will need 38,500 transmitters! To cover the same area with DAB+, you will need only 30 transmitters. And Norway is over 10 times bigger than Holland. The electricity used on the transmitter side is clearly much lower for DAB+ than for 3G, 4G or Wi-Fi, although I have not gone into detail of the transmitting side in this post. For DAB vs FM comparisons, see here.
Let us also compare with FM. The two DAB networks that will provide 90 and 99.5 percent of the population with indoor digital radio coverage use half the electricity of the current FM networks. The two DAB networks will be completed late next year.
But all of this is on the transmitting side of things. What about the reciving side? My mobile phone is a Samsung SIII. It is around 9 months old, but the battery (3.8 V, 2,000mAh) is still doing a pretty good job. I decided to put it to a small test, although completelly non-scientific.
Battery life via streaming
I used NRK’s radio app to measure streaming.
I recharged the battery completely and started listening to one of NRKs radio stations via streaming over 3G. The phone was at all times in an excellent coverage area. The phone was not used for other things, and the screen was kept off. I used earplugs at all times, with the volume at the maximum level.
I could listen to radio for 6 hours and 53 minutes before the battery was flat and my phone died. Not bad, I’d say. I had expected worse. After all, when you stream a live signal, wether radio or television, the phone needs to do a lot of processing. Think of streaming as pressing the F5 button on your keyboard continuously, only much faster than what you are capable of doing manually. Everytime the data is being refreshed. Real-time entertainment or radio, television and recorded programs are examples of synchronous services. You will need a minimum of available bandwidth to your receiver in order to get an acceptable experience without buffering, and your device needs enough processing power in order to manage to decode the signal at the bandwidth in question. To do so requires power. The battery could in this case cope for less than seven hours.
Battery life via broadcasting There are not yet any mobile phones with built in DAB available on the mass market, so I had to do the second test via FM which comes inside my Samsung SIII.
I recharged the battery completely yet again. The phone was also now not used for other things, the screen was kept off and the volume was at the maximum level throughout. In this case I had to use earplugs as they also function as an antenna for the FM signal. An advantage with a broadcasting chipset is that the processing is done on the chipset, so the phone’s processor is used much less, and therefore requires much less power.
I could listen to FM radio for 48 hours and 12 minutes on one charge. Although I did admittedly sleep through a lot of it, with the radio playing on maximum volume in my living room. As the battery lasted much longer with FM, I carried the phone with me in areas with different signal-strengths. The result could have been even better in “perfect” receiving conditions, as was the case with the streamed test above.
DAB vs. FM How DAB compares with FM? Both DAB and FM come on the same chipsets and the power consumption of the two reception methods is almost identical. We do however see that DAB reception uses less power than FM reception on some modern chipsets.
Conclusion These two measurements were done by me in an uncontrolled environment and I do not claim that what I measured proves anything from a scientific perspective. But I will say that there is a clear indication of differences in power consumption between streamed radio and broadcasted radio. You can easily test this yourself. Given that your mobile phone comes with FM or DAB.
It doesn’t?
Please write to Samsung, Nokia, HTC, Apple or your other preferred phone manufacturer and ask that they put it in in their next version. For the sake of the environment, the available services on your phone and its battery life.
Radio via FM lets me listen over 7 times longer than radio via 3G.
And what would happen if everyone in the country were to stop listening to broadcast radio and only listen to streamed web radio? You do the maths.
For a political party to even suggest, on environmentally grounds, that radio should be distributed via mobile internet instead of broadcasting, is beyond any reasonable logic. And this is not even taking into account the tens of thousands, if not hundreds of thousands of additional transmitters needed for 4G to cover Norway. The costs of building 3G or 4G to 99.5% coverage in Norway would be enormous. Telenor, which is the biggest MNO in Norway, even says that Norway will never get full mobile coverage via GSM. Let alone via 3G.
Let us finally not forget coverage issues, emergencies or available capacity. It is also cheaper to build DAB+ from scratch than to upgrade the existing FM networks.
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