Turning off the FM signal

[Gordon]

All that's needed to make ordinary DAB sound more than reasonable for music broadcasts is the bit rate changing from 192 kbps to 256 kbps. Park the cynicism and campaign for that instead. That's a battle you might win.

It might well take some of the sting out of the debate. Musing on this earlier today it occurred to me that currently the BBC multiplex uses a DAB profile with error control setting UEP3 which gives a code rate of around one half. That is out of 2 bits transmitted only one is the audio the other is a protection bit. So out of the gross bit rate of about 2.3 MBit/s in the multiplex the net is about half that. Each service [R1, R2, R3 etc] can be coded separately. If we used UEP4 for R3 instead of UEP3 we'd release some error coding bits to be used for the audio and this would get us to 224. Going to UEP5 we'd get to 256 and be able to give a few bits back to the multiplex too! The change is trivial at the coding end and receivers would just follow the signal.

So why not do it? Well, no lunch is free and the cost of this is reduced robustness taking the form of a reduced service area to the tune of 1.7 dB for 224 and 5.3 dB for 256. People living well inside the area would probably not notice the change to UEP4 but those living at the edge could lose service. More would lose service at UEP5. How many is hard to say but is it a price worth paying? Moving R3 to UEP4 seems worth a debate?

[Nick_G]

It might well take some of the sting out of the debate. Musing on this earlier today it occurred to me that currently the BBC multiplex uses a DAB profile with error control setting UEP3 which gives a code rate of around one half. That is out of 2 bits transmitted only one is the audio the other is a protection bit. So out of the gross bit rate of about 2.3 MBit/s in the multiplex the net is about half that. Each service [R1, R2, R3 etc] can be coded separately. If we used UEP4 for R3 instead of UEP3 we'd release some error coding bits to be used for the audio and this would get us to 224. Going to UEP5 we'd get to 256 and be able to give a few bits back to the multiplex too! The change is trivial at the coding end and receivers would just follow the signal.

So why not do it? Well, no lunch is free and the cost of this is reduced robustness taking the form of a reduced service area to the tune of 1.7 dB for 224 and 5.3 dB for 256. People living well inside the area would probably not notice the change to UEP4 but those living at the edge could lose service. More would lose service at UEP5. How many is hard to say but is it a price worth paying? Moving R3 to UEP4 seems worth a debate?

A very good reason for not upping the bit-rate of music broadcasts to 256 kb/s is because most DAB receivers cannot decode streams > 192 kb/s. <sarcasm>Some really forward-thinking planning there.</sarcasm>

[amateur51]

A very good reason for not upping the bit-rate of music broadcasts to 256 kb/s is because most DAB receivers cannot decode streams > 192 kb/s. <sarcasm>Some really forward-thinking planning there.</sarcasm>

Loving your <sarcasm> Nick_G

Welcome by the way! - great to have your expertise 'on board'

[Nick_G]

Loving your <sarcasm> Nick_G

Welcome by the way! - great to have your expertise 'on board'

Thanks for that.

I wouldn't say I'm an expert by any stretch of the imagination but you do read a lot on the pros & cons of DAB on another forum that I post on.

I'm sure 4G will have teething problems as was mentioned in previous posts but once it is established DAB will become an expensive irrelevance. I still think that could happen within the next 10 years.

[Gordon]

Gordon, your post about downshifting DTT and bandwidth constraints. Radio 3 down-bitted to 48kbps perhaps on Freeview ?

Don't give them ideas! By the way, the Digital Mobile Spectrum Limited [DMSL] company [was "MitCo"] is now known in the trade as "DAMSEL", after that well known lady in distress!!

[Gordon]

A very good reason for not upping the bit-rate of music broadcasts to 256 kb/s is because most DAB receivers cannot decode streams > 192 kb/s. <sarcasm>Some really forward-thinking planning there.</sarcasm>

You mean - shock horror! - that some receivers out there are not compliant to ETSI 300 301!! Whatever next.

[Gordon]

Thinking of a new car with DAB?

http://radiotoday.co.uk/2012/11/bmw-to-include-dab-radio-in-all-new-cars/

http://www.cisionwire.com/cap/r/bmw-s-roll-out-of-dab-radio-as-standard-will-prompt-all-carmakers-to-follow--says-cap,c9335417

http://www.autotrader.co.uk/articles/2012/11/cars/bmw/digital-radio-to-become-standard-on-bmws

http://www.fleetdirectory.co.uk/fleet-news/index.php/2012/11/16/is-your-car-ready-for-the-digital-radio-revolution/

http://ertonline.co.uk/ERT%20Latest%20News/dab-as-standard-in-all-bmw-cars-from-2013.htm

[Dave2002]

Regarding 4G, the Ofcom requirements has a clause that states that 4G coverage should reach 97% of the population by the end of 2017. With the new IP protocols and 4G incorporating multicast as standard this will make it much easier and cheaper to deliver multiple streams to listeners. Give it 10, maybe 15 years and I think we'll be there, maybe sooner. Once this happens, then what would be the point of continuing with DAB?

Even if we ignore the likelihood of 4G's disruption to Freeview services, it doesn't currently seem like a good technology for wide area coverage in the near future. My understanding is that, in any case, 4G is not a single technology, but rather an aspirational level of service provision, which can possibly be provided by several different underlying technology systems. This may require a dense distribution of base stations, which may be feasible in some cities, but 4G coverage is likely to be poor outside city areas. I would also suggest it's too early to tell. In the London area even the 3G system is often challenged, and my understanding is that 4G is only just being switched on.

On motorways around the country 3G networks do not provide anything like the service continuity of FM or DAB, IMO, so I doubt that 4G will be competitive in the next few years. Further, thinking back to the enthusiasm in the early 2000s for so-called "wireless cities", many such projects actually stalled or were cancelled because the costs were significantly higher than expected, and levels of service lower. This doesn't mean that having wireless broadband technology available is a bad idea, and indeed for some situations, such as emergency communications it has proved valuable, but using it for radio distribution may not be the most sensible thing to do unless 4G can also be made both technically and financially effective. The assumption that so many users will want to use it and pay for it thus leading to a financially self sustaining infrastructure which will match usage may also be found to be false. It's really too early to tell, but right now things are certainly not looking hopeful for 2017.

[Nick_G]

Even if we ignore the likelihood of 4G's disruption to Freeview services, it doesn't currently seem like a good technology for wide area coverage in the near future. My understanding is that, in any case, 4G is not a single technology, but rather an aspirational level of service provision, which can possibly be provided by several different underlying technology systems. This may require a dense distribution of base stations, which may be feasible in some cities, but 4G coverage is likely to be poor outside city areas. I would also suggest it's too early to tell. In the London area even the 3G system is often challenged, and my understanding is that 4G is only just being switched on.

On motorways around the country 3G networks do not provide anything like the service continuity of FM or DAB, IMO, so I doubt that 4G will be competitive in the next few years. Further, thinking back to the enthusiasm in the early 2000s for so-called "wireless cities", many such projects actually stalled or were cancelled because the costs were significantly higher than expected, and levels of service lower. This doesn't mean that having wireless broadband technology available is a bad idea, and indeed for some situations, such as emergency communications it has proved valuable, but using it for radio distribution may not be the most sensible thing to do unless 4G can also be made both technically and financially effective. The assumption that so many users will want to use it and pay for it thus leading to a financially self sustaining infrastructure which will match usage may also be found to be false. It's really too early to tell, but right now things are certainly not looking hopeful for 2017.

Well we shall see. Getting widespread 4G coverage and multicast is much more important than rolling out DAB IMO, as it doesn't just benefit broadcasters or listeners, it benefits the UK economy.

I still think IP-based distribution will overtake DAB in the next 10 years.

Regards,
Nick

[An_Inspector_Calls]

I still think IP-based distribution will overtake DAB in the next 10 years.

Regards,
Nick

Agreed. We're going to see an improvement in internet connection speeds in the next decade that, in my opinion, will change both the way we receive radio and television.

[Dave2002]

Agreed. We're going to see an improvement in internet connection speeds in the next decade that, in my opinion, will change both the way we receive radio and television.

I'm more cautious. Wired broadband systems should provide much better service over even the next five years, though the UK has been lagging behind despite politicians' pronouncements and aspirations to be at the forefront of developments. Wired systems should open up high quality media on demand services - we're almost there with iPlayer.
Wireless systems are going to present tougher nuts to crack, and I'm suspecting we won't actually achieve good reliable ubiquitous and comprehensive coverage over the whole of the UK within a decade. Sorry, but that is my prediction. On the other hand countries like Pakistan already have WiMax services which can be accessed directly by end users, and of course South Korea leads most of the rest of the world.

[An_Inspector_Calls]

I'm more cautious. Wired broadband systems should provide much better service over even the next five years, though the UK has been lagging behind despite politicians' pronouncements and aspirations to be at the forefront of developments. Wired systems should open up high quality media on demand services - we're almost there with iPlayer.
Wireless systems are going to present tougher nuts to crack, and I'm suspecting we won't actually achieve good reliable ubiquitous and comprehensive coverage over the whole of the UK within a decade. Sorry, but that is my prediction. On the other hand countries like Pakistan already have WiMax services which can be accessed directly by end users, and of course South Korea leads most of the rest of the world.

I wasn't thinking of an improvement of connection speeds wirelessly, but by improvements to connections over the final mile - probably optic fibre to most homes. Mobile reception methods are more difficult to predict.

[Dave2002]

I wasn't thinking of an improvement of connection speeds wirelessly, but by improvements to connections over the final mile - probably optic fibre to most homes. Mobile reception methods are more difficult to predict.

AIC
I do agree with this, but Nick was suggesting that 4G would take over and become a significant means of delivery. It might, but my feeling is that it will be too expensive to "waste" on services which can be provided by standard broadcast methods, including DAB. See http://www.emc.com/leadership/tech-v...redictions.htm for some comments on predictions and the Negroponte Flip and the new to me Pelton Merge.

[Resurrection Man]

...... as it doesn't just benefit broadcasters or listeners, it benefits the UK economy.

.....

Can you please say how it does this? I have heard the politicians keep banging on about this but can't see how it is going to benefit the UK economy.

[Resurrection Man]

Agreed. We're going to see an improvement in internet connection speeds in the next decade that, in my opinion, will change both the way we receive radio and television.

But will the overall effect be any different from today? Isn't digital data transmission a bit like Parkinson's law ? Only the other day, I was reading about how much the increase demand there has been on mobile data as apparently people like watching videos on their teensy phone screen and that this is accelerating the need to shove Freeview further down the spectrum to free up more bandwidth.

I also think that that increase is going to be in towns and cities. Certainly not in rural areas.