kenneth, I have not read the HSDPA spec myself but my assumption is that it is "all packet, all the time" As the "P" implies in "HSDPA" UMTS, as a superset of HSDPA incorporates various QOS and other features (roaming, voice connection awareness, etc) that are needed in order to properly handle voice traffic as a part of the total packet stream on a UMTS network. As I understand it, the key difference between voice traffic on a 3g network vs voice traffic on a 4 g network such as one based on, LTE, or WIMAX is that on a 4 g network the network core is packetized and runs IP (or at least an connectionless packetized core with a network protocol that looks like IP) with QOS enhancements for the voice packets. On the other hand, on a 3 g network with HSUPA or HSDPA, the voice traffic, although it may be statistically multiplexed, is not competing for the same bandwidth as the HSUPA/HSDPA packets. Perhaps a 3G expert on this list could clarify this somewhat subtle point. if not I will dig into the spec myself to figure this out. I have always (professionally speaking) considered voice as a particular case of data (bits if you will) with specific characteristics, i.e. connection oriented, duplex content flow, streaming, delay sensitive, and relatively narrow bandwidth (i.e. frequency limited) per "conversation"/connection. My assumption is that most GSM mobile network service providers who are evolving to 3G are building HSDPA overlay networks to first (and primarily) convey non-voice data (by my definition, above, not an oxymoron) just as the CDMA based mobile network service providers have built EVDO overlays to do the same thing. In other words those GSM service providers are not attempting to move their voice traffic to UMTS right away. A key difference between HSDPA/UMTS on the one hand and EVDO/CDMA on the other (in terms of application of the underlying technology) is that, in the U.S. at least the CDMA/EVDO providers (the largest being Verizon and Sprint) are not themselves using EVDO to convey voice although the end user of EVDO service could certainly do so (e.g. SKYPE or arrangement with a SIP trunking provider). They are using EVDO service to meet new and growing demand for broadband wireless Internet access. On the other hand mobile service providers who are evolving from GSM to 3G/UMTS can, if they so choose, start to move their voice traffic over to their UMTS infrastructure (equipment and RF) and do so gradually by providing their customers with dual mode 2g/3g handsets. Although the UMTS standard, supports call handoff from GSM to UMTS, I have to wonder how much of that is actually going on right now since the user would have a dual mode (GSM + 3G) handset and the network would have to be engineered to implement such inter-technology (GSM<=>3G) handoff/roaming. Best Regards, John Holmblad Acadia Secure Networks, LLC * * kenneth marken wrote: > John Holmblad wrote: >> Andrew, >> >> yes, I am being overly presumptuous as to what kind of radio >> technology will and will not be in the next turn of the IT hardware. >> I must have read it somewhere that it was going to be HSDPA only. >> > > HSDPA do not result in data only, as HSDPA only builds on UMTS. and > UMTS carry voice just fine... > > _______________________________________________ maemo-users mailing list maemo-users@xxxxxxxxx https://lists.maemo.org/mailman/listinfo/maemo-users
