VoHSPA aims to steal some of VoLTE's thunder

Voice over LTE, move over: There's a new VoIP in town, and it's Voice over HSPA.

The 4G Americas trade group is promoting VoHSPA via a white paper that describes potential VoHSPA benefits, including increased network spectral efficiency. The group contends that VoHSPA calls can be delivered more efficiently from a spectral standpoint over packet-switched (PS) rather than circuit-switched networks, thus freeing up radio resources for additional data traffic.

"There has been a lot of discussion regarding the anticipated launch of Voice over LTE, or VoLTE, services in the coming year. Now, similar opportunities are being developed for HSPA that allow operators to deliver Voice over HSPA," said Chris Pearson, president of 4G Americas. "Voice over HSPA could allow 3GPP operators significant flexibility by using packet-based technology to deliver voice, as HSPA serves to blaze the trail for mobile broadband and LTE gains significant momentum. Both mobile operators and consumers stand to benefit significantly from innovative, robust and efficient services like Voice over HSPA and VoLTE." 

The white paper suggests two potential options for VoHSPA. One option is referred to as IMS Voice over HSPA or simply IMS Voice, which is self explanatory.  The other entails modifying existing circuit-switch based techniques so that those communications can be transmitted over HSPA infrastructure, and is referred to as CS Voice over HSPA (CSoHS).  

Either option offers significant data capacity and battery life gains," said Bob Calaff, director of technology and spectrum strategy for T-Mobile USA and the 4G Americas project leader for the white paper. "The good news is that virtually all of the features believed necessary for a robust VoHSPA service are either presently available or expected to be available from equipment vendors in the 2012 to 2013 timeframe for testing and validation," he said.

 The 4G Americas report defines work completed by the GSM Association for a minimum mandatory set of features defined in existing 3GPP Release 8 specifications that should be implemented in order to insure an interoperable, high quality, IMS-based telephony service over an HSPA radio access layer.

VoLTE has progressed considerably, despite the fact that LTE networks were deployed long after HSPA networks first debuted. Traditional CDMA operators, in particular, have been making aggressive plans for VoLTE. One operator to watch is MetroPCS (NASDAQ:PCS), which announced in October that it had completed its first VoLTE call using end-to-end commercial equipment, and it plans to launch VoLTE this year. Ed Chao, head of engineering for MetroPCS, was named one of FierceWireless' 2012 Rising Stars of Wireless.

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