There are more ways to do it.
The best is get training at vendor’s official training centre. E.g for Siemens MSC yuo can go in Munich Information and Telecomm. training centre where have a lot of training courses for GSM….http://ictraining.mchh.siemens.de/eng/
As far as telecom there is no internationally recognized certifications like in Networking, say MCSE, CCNA, etc. So this certfications may not help you much, till u get a job in the secific product which u obtained training and are so expensive too. Usually it’s wise to get certified in the specific product which ur working on.