Lecture Series in Mobile Telecommunications and Networks (1583KB)

From plain old Telephony to flawless mobile audio communication
bandwidth extension module at the transmitter side will do the job. However, there is still much work to do and the
listening tests have to be done on a broad basis.
Perhaps I could just add a further comment to the last question. If we are moving towards UMTS LTE, and we are
allowed to increase somewhat the bit rate, then the codecs will become more and more transparent to any kind of
strange dialect.
Andy Evans (Cable & Wireless EAUS): I just wondered how much interest there is in the standards forums in actually
adopting these different codecs in future mobile standards – particularly LTE?
Peter Vary: As far as I understand it – and I guess Mike can comment on that – one of the main reasons for the NGMN
initiative is that there are too many standards and that the operators are surprised that there are the solutions A, B, C
and D and you have to implement them all and then you will see on the market whether it is a good solution or not,
and whether it is taken or not. The operators try to steer the standardisation and to settle all the critical issues, including
the IPR method, before the standard is written.
Michael Walker: I can add to that. One of the big costs in the business is that, because of the standardisation process,
you often have multiple solutions for the same problem. All those solutions get implemented in the equipment and
that is a waste of the resource. If we are going to see technologies like this, which could actually offer the user much
more benefit, having multiple choices for basic functionality, then we have to resolve that problem.
Dr Tim Moulsley (HJM Ltd): I am an independent consultant but formerly I was with Philips.
Peter Vary: Yes, you were a colleague of mine.
Tim Moulsley: Just picking up the point we are on now, which is looking at the standards for codecs, I wonder how
the take-over of an all-IP network, both in fixed and in mobile, will affect this kind of debate. That would tend to push
the codec to the application level, where there is much more flexibility about which codec standard you actually have,
than if it is in as part of the wireless network or part of the telecoms network itself. Would you like to comment on that?
Peter Vary: My impression is that voice-over IP is actually the driving force to introduce wideband in cellular. The point
is that no one has the chance to listen to a phone in the shop. If you go to a shop to buy a telephone, you have no idea
and you don’t think that it makes any sense to listen to the quality – because a phone has a certain quality and it is a
phone.
Now, however, we see some experienced users having voice-over IP communication. Voice-over IP can be significantly
worse or sometimes much better. Many things are going on there. We have Skype and we have SIP telephones.
We have the evolution of cordless telephones, the DECT telephones. They have now decided to implemented
wideband the codec and you can buy DECT telephones which have two connections to networks – one traditional
network, the telephone network, and one to the DSL router at your home. If you connect it to the DSL router, you have
wideband speech with excellent quality.
You have greater flexibility in voice-over IP and this will sort out which codecs will survive. There is also a debate
between the mobile community and the IP community – that is, ITU on one side and 3GPP – as to whether we should
use a universal codec in future in both fixed and wireless networks. There is some hope because they are talking to
each other to get the same codec under a 3GPP number and under an ITU number. Some voice-over IP operators are
already using AMR wideband.
Professor Chris Guy (University of Reading): There is rather a chicken and egg situation here, because you have the
operators and the handset manufacturers but who will jump first and implement it? One has to go before the other.
Peter Vary: I try have tried to support this topic of wideband for many years, because I like it. I have been involved in
many talks and contacts with manufacturers and operators. What you usually hear is that the manufacturers are saying
that the operator does not require it, while the operator is saying that there are no terminals. I heard the same story just
last week.
I said to the operators that, if they introduced wideband, that would be some improvement compared to their
competitors, and people would talk for longer. They would do more business if they had wideband codec. That is what
The Royal Academy of Engineering 57