What is AMR-WB Anyway?

After noticing that the Nokia E75 announces SIP AMR-WB capabilities I did some follow up work to see where it is standardized and how universal it is. According to Wikipedia, AMR-WB is specified in ITU G.722.2. Several bit rates are available and what I can see in 3GPP, codec rates up to 12.65 kbit/s are used in wireless. Makes sense as that is a similar maximum bit rate as for EFR (Enhanced Full Rate) or AMR-FR (Adaptive Multi Rate – Full Rate) in GSM and UMTS today, i.e. the same air interface bandwidth is required as for todays codecs.

To be able to use AMR-WB in wireless networks, transcoders need to be deactivated in the network. The features for this are Tandem Free Operation (TFO) and Transcoding Free Operation (TrFO) in GSM and UMTS respectively. For details on those see a blog entry I wrote back in 2006 (!). Interestingly enough, this blog entry is still very popular so it looks like quite a number of people are working on this.

So what about fixed line networks? Here, my picture gets a bit sketchier but I'll try to put the pieces together here. If you have different/additional info, please let me know. The successor to the current cordless digital standard (DECT) is called Cat-iq. Again according to Wikipedia, the wideband voice standard used here G.722 at 64 kbit/s. G.722 is the big brother of G.722.2 and they don't seem to be compatible. Also, it seems that the wideband codec can only be used over an IP link, i.e. the phone must be connected to a SIP VoIP provider. On this thread, Frank-Christian Kroegel mentions that ISDN can also be used for the wideband codec but it seems that is not done in practice yet. And anyway, except for Germany and a few other countries, ISDN is not widely deployed anyway. 

So it looks like wideband voice is going different ways in fixed and mobile networks for the moment. That's a pity but who knows, with fixed and wireless networks operators merging again these days, things might change in the future. I wonder how long it will take to have a wideband voice future besides with Skype?

3 thoughts on “What is AMR-WB Anyway?”

  1. I don’t have an answer, but I noticed that the brand new Siemens IP DECT phone I bought does support G.722 as a codec you need to activate manually.
    (Btw, that Siemens phone is really suprisingly powerful: In France, behind a Freebox, it allows full multiline integration of analog line plus several SIP accounts in completely transparent way – allowing me to have both a German and a French phone number, all going to the same single handset.)

Comments are closed.