The CSFB voice call was made through Huawei's STREAM 201HW smartphone. To complete the call, the AXGP (Advanced eXtended Global Platform) network was connected with the UMTS network of SOFTBANK MOBILE. AXGP is a network compatible with the LTE TDD of Wireless City Planning Inc., a SoftBank Group company. Huawei's STREAM 201HW smartphone, which is currently available through SOFTBANK MOBILE in Japan, uses a customized Qualcomm chip supporting both LTE TDD (AXGP) and UMTS.
Mr. Deng Taihua, Huawei President for LTE TDD/WiMAX/TDS Networks, said: "Huawei is honored to provide SOFTBANK MOBILE with this CSFB solution. Interoperation between GSM/UMTS/LTE networks is always a concern for operators. During trials in India August last year, Huawei completed the world's first multiple live handover scenarios across GSM/UMTS/LTE. We are committed to commercializing LTE TDD key solutions for our customers."
http://www.huawei.com/en/about-huawei/newsroom/press-release/hw-195764-csfblte.htm
