Circuit Switched Fall Back (CSFB) from LTE TDD (TD-LTE) to GSM based on Release 9 of the 3GPP standard offers LTE devices enhanced support for voice and SMS, using the broadly installed base of GSM networks. Live, public demonstration at the PT Expo in Beijing was held with Ericsson LTE TDD network and Qualcomm chipset. Supports development of LTE multi-mode devices, providing better user experience through the implementation of Release 9 CSFB in the network and device.

The new generation mobile communication standard LTE is expanding rapidly as data traffic over mobile networks grows 15 times every year. Ericsson (NASDAQ: ERIC) estimates that smartphone subscriptions will reach around 3 billion in 2017.

While data traffic is increasing and IP-based packet networks, like LTE, are adopted globally, coverage for voice and SMS is still larger in legacy circuit-switched networks such as GSM. Already today, 85 percent of people on Earth have access to GSM mobile communication networks and Ericsson estimates that 90 percent of the world’s population will be covered by 2017.

In order to facilitate re-use of existing GSM networks, Ericsson and Qualcomm Incorporated have demonstrated the world’s first Release 9 Circuit Switched Fall Back (CSFB) from LTE TDD (TD-LTE) to GSM, live, using a standard Ericsson radio base station RBS 6000 and an LTE multimode chipset from Qualcomm. With this achievement, both LTE FDD and LTE TDD modes, using un-paired spectrum, could also make use of the broad GSM coverage.

Serge Willenegger, Vice President Product Management at Qualcomm, says: “We are pleased to be part of this important industry milestone, having worked very closely with Ericsson. The efficient support of voice and messaging services in LTE multimode smartphone platforms is instrumental in driving device economies of scale in key LTE TDD regions such as China. CSFB utilizes the same power-efficient, single radio chipset architecture from Qualcomm that has been widely proven for LTE FDD CSFB support.”

Per Narvinger, Head of Product Line LTE, Business Unit Networks, Ericsson says: “For carriers and service providers, available frequency bands for communication services are limited and precious resources. Multi-mode networks and devices that make the best use of these resources are crucial for providers to be able to stay competitive and serve consumers in the best way. LTE TDD, which uses un-paired spectrum, is one of the important technologies to support rapid uptake of smartphones and data traffic growth in operator networks.”

Notes to editors

LTE voice evolution: Phase one. "Circuit-switched fallback. The first phase of voice evolution for mobile LTE services"

Press backgrounder: What is Voice-over-LTE (VoLTE)? (PDF)

White Paper: Voice and video calling over LTE - a step towards future telephony

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