Telecom engineer can work in many fields… as far as i know, the 1st step is to steer into the most popular radio access technology (3G).
On the other hand, you could decide to wok in the core network (IMS, Applications, Media Gateways, MSC, etc)
If you go in R.A.T, then either:
– network design
– network architecture
– equipment configuration / maintenance / installation
– network planning
– radio optimization
– radio qos monitoring
… that’s all i can think of..