Digitally modulated signals fill space and travel through almost every wired and optical network. Today, almost all wireless services use a plethora of complex carrier modulation schemes. The continuous improvement in modulation technologies and components and advances in error-correction codes have increased channel capacity close to the fundamental limit as set by the Shannon-Hartley theorem.
Capacity and efficiency have been improved even more through the development of new transmission strategies such as MIMO (Multiple-In-Multiple-Out) antenna technology and the implementation of extremely flexible multiple-access schemes in the time, frequency, and code domains. Additionally, more and more products and services with decreasing prices rely on the capability of one or more wireless technologies to operate properly.
Read the full version of this whitepaper here: cp.literature.agilent.com/litweb/pdf/5991-1100EN.pdf