GCF stands for Global Certification Forum. It is primarily composed of network operators, GSM terminal manufacturers, GSM testing equipment manufacturers, and third-party GSM model certification testing laboratories from around the world. 
The goal of GCF is to ensure global interoperability of terminals through an independent certification process. GCF certification is based on a voluntary principle and operates in a forum format
In Europe, terminal manufacturers are required to complete testing according to GCF certification standards, or conduct tests based on these standards. GCF certification also serves as the foundation for certification required by major European operators. 
Communications products entering the European market must provide a GCF certificate, and GCF certification is mandatory for operator approval in Europe.