MWC: Qualcomm and Ericsson Hand Calls From LTE To WCDMA

Qualcomm and Ericsson have achieved an important step in the development of LTE technology:  the world’s first voice handover between LTE and WCDMA networks.

The successful handover of a voice call from LTE (Long-Term Evolution, so-called 4G) to WCDMA (or 3G) on an Ericsson end-to-end network was achieved just days before Christmas on 23 December, 2011, using a handset which incorporated Qualcomm’s Snapdragon S4 MSM8960 3G/LTE multimode processor.

Mobile Breakthrough

The successful handover is very significant indeed, because up until this point, 4G networks have used LTE predominately for mobile data, and not voice.

However many operators are starting to evolve their LTE networks to support voice and SMS, as well as support the arrival of LTE smartphones.

One of the problems for operators posed by voice over LTE networks is what happens when the end-user steps outside the LTE network coverage area. In the UK for example, when a UK user steps outside a 3G GSM area, their handset should seamlessly switch to a 2G GPRS network without causing the voice call to be dropped or interrupted.

As voice-over LTE is entirely, using IP-based technology, it means that voice-over LTE carriers could eventually eliminate 3G CDMA and GSM networks. Qualcomm said it will show off the advancement at Mobile World Congress in Barcelona at the end of February.

SRVCC Hand-off

So how was this breakthrough achieved? Well it seems that the LTE voice to WCDMA hand-off was made possible thanks to a technology called Single Radio Voice Call Continuity, or SRVCC.

SRVCC enables continuity of service by switching to a WCDMA network when a consumer on a voice-over LTE call leaves the LTE network’s coverage area. And it seems that SRVCC also supports both LTE and 3G network connections on a single chip. This eliminates the need for separate LTE and 3G radios and modems within the handset, which should in turn lead to thinner LTE devices, with a better battery life.

“As LTE networks are deployed alongside 3G networks, the ability for multimode 3G/LTE mobile devices to connect to different network technologies will be an important part of providing the best possible mobile voice and data experience to consumers,” said Cristiano Amon, senior VP of product management at Qualcomm. “Qualcomm is committed to the successful deployment of LTE networks worldwide in conjunction with 3G networks, and the milestone we’ve achieved with Ericsson is another step towards making VoLTE technology a commercial reality.”

“By accomplishing this advanced LTE handover technology together with Qualcomm, we now ensure that operators can meet consumers’ expectations on a high-quality voice over LTE service,” said Johan Wibergh, Head of Business Unit Networks, Ericsson. “Operators will be able to maintain their quality brand for their voice business when they launch voice over LTE.”

LTE Deployments

This important development comes at a time when LTE networks are increasingly being deployed around the world.

The UK in particular has been a slow starter, but recently Everything Everywhere and BT revealed they would extend their 4G LTE trial in Cornwall to patch mobile not-spots. O2 has already trialed 4G LTE in central London and since 2009 has been holding its own LTE trial in Slough. Vodafone has also conducted its own trials.

Yet the UK has in general been tardy in its uptake of 4G compared to other nations. LTE networks have already been launched in the US, Germany, Japan and emerging markets such as Uzbekistan.

This means that the UK will be four years behind the world’s first LTE deployments in Oslo and Stockolm and three years behind the first commercial service in the United States. This delay is despite a survey from the policy advisory group Open Digital in October, which warned that the delay in rolling out 4G will cost British businesses £730 million a year.

Iit is worth noting that the arrival of 4G networks has not been entirely smooth. In the US, LTE networks have already been build by Verizon Wireless, but in December the operator was forced to explain why it suffered a service outage that affected many users across the United States.

The problem was reportedly with the hand-off between Verizon’s 3G and 4G networks.

Corruption Probe

Qualcomm meanwhile is facing a corruption probe.

It revealed in a SEC filing that it is the subject of a investigation by the SEC and the Justice Department into possible violations of foreign bribery law, which prohibits bribing foreign officials to get or keep business.

“The company believes that it is in compliance with the requirements of the FCPA and will continue to cooperate with both agencies,” said Qualcomm in the filing.