- Rohde & Schwarz GmbH & Co KG
- AT&T Inc.
- Verizon Communications Inc.
- Telefonaktiebolaget LM Ericsson
- GL Communications Inc.
- Reliance Jio Infocomm Limited
- Bharati Airtel Limited
- SK Telecom Co. Ltd
- iBASIS Inc.
- LG Uplus Corp.
- KT Corporation
- KDDI Corporation