4. Tools

A number of new issues need to be resolved if SCN is to become a reality. The primary goal is to deliver more bandwidth at lower cost and in an energy-efficient way. Two trends have recently emerged to address this problem:

• sophisticated wireless communication techniques, such as multi-antenna, interference alignment and multi-user detection technologies;

• on the other hand, advanced mechanisms such as information relay, self-organization, cooperation between SBs (known as network MIMO) and flexible radio.

  These developments call for interdisciplinary research involving the tools we introduce below.

• Theoretical performance limits

  The study of SCNs using information theory reveals the fundamental limits...