However, based on the accompanying demo, Unstrung is not 100 percent convinced…
Ericsson is using software from Sonim Technologies Inc. to offer this push-to-talk (PTT) service. (PTT services allow users -- with suitable client software on their handsets -- to have short, back-and-forth conversations with single users or groups of users on a network, which is why they are sometimes likened to digital walkie-talkie systems.)
However, when the system, which is the first to allow PTT services between Code-Division Multiple Access (CDMA) 2000 and General Packet Radio Service (GPRS) networks (see A Wireless Taxonomy for in-depth definitions) was demonstrated to Unstrung this morning, it just plumb didn't work.
Johan Bjorklund, manager of product and technical marketing for CDMA systems at Ericsson, had trouble connecting and transmitting between GPRS and CDMA handsets. "The show's started, the other guys [gesturing at Nextel Communications Inc. (Nasdaq: NXTL) booth] must have just switched their radios on [ed. note: supposedly eating up all the available bandwidth]," he told Unstrung after a couple of failed attempts to get it working.
The lackluster demo rather undercut Ericsson's claims at the show to have solved the problems of implementing a PTT service on a CDMA network.
The main ones revolve around the time it takes to connect to the network (call setup time) and the time it takes to transfer data across the network (latency). Often, call setup times and latency on CDMA can lead to a long wait to be connected and a very "bursty" transmission (see Walking, Not Running, to PTT for more on this). Ericsson says that it has got its CDMA call setup times down to less than two seconds and less than one second for network latency. Ericsson isn't really saying much about how it has improved CDMA PTT performance. "We've been working very hard on this," says Peter Lancia, director of product and technical marketing for CDMA systems at Ericsson [ed. note: oh, that's helpful].
Push-to-talk systems also can lead to capacity problems on GPRS networks. The VOIP data eats into the precious bandwidth needed for actual voice calls. Lancia says Ericsson has implemented "compression routines" to deal with this problem.
However, Ericsson will need to improve its demonstrations of the technology before operators start knocking at its doors. — Dan Jones, Senior Editor, Unstrung