There are three areas of focus within this field:
The communications engineer is concerned with the efficient and reliable transmission of information over noisy channels. Such channels arise in many applications, e.g., cellular radio systems, satellite broadcasting systems, magnetic or optical recording systems (disks and DVDs), fiber-optic or coaxial cable systems, etc. Companies that hire communications engineers include communications equipment manufacturers such as RIM, Qualcomm, Motorola, Nokia, and Ericsson.
The network engineer is concerned with the design of protocols and algorithms that permit efficient utilization and efficient access to communications infrastructure such as the Internet, cellular radio networks, the telephone network, etc. Network security, packet switching, Internet protocols, local-area networking,peer-to-peer file sharing schemes, and many more topics are all part of this huge field. Companies like RIM, Bell Canada, Telus, AT&T, Verizon all operate enormous networks, and many Fortune 500 companies have private network systems of their own and require graduates with network engineering skills.
Signal processing engineers take multimedia information sources (e.g., speech, music, images, videos, etc.), convert them into digital form, and manipulate the signals using digital processing techniques (DSP) on a computer. There are many applications for DSP in communications, biomedical engineering, bioinformatics, audio, image and video processing systems, including stereo equipment and iPods. For example, a computerized finger print recognition system would use many DSP techniques, as would a high-end music synthesizer. Many employers in the computer, electronics and audio industries employ graduates with this knowledge. This includes companies like Apple, Microsoft, Agilent, Bose, RIM, Spectrum and many others.