AERIAL ENTROPY AND CAPACITY OF A MEA EM SOURCE

摘要

This paper presents a novel approach that describes the entropy and capacity of a multi-element array (MEA) electromagnetic (EM) radiation source in terms of the far-field characteristics of its radiation pattern. The presented approach shows that the entropy of a MEA EM source at the far field is equal to the sum, of the entropy of a reference signal driven into one of the antenna elements and the entropy introduced by the uncertainty created by varying the radiation pattern characteristics of the array on each symbol period. The latter is defined as the aerial entropy of the information source as it is encoded by varying the way in which the EM signal is transmitted into the air, and it helps identify problems related to the distinction between digital beamforming (DBF), transmit diversity and multiple-input multiple-output (MIMO) systems, while paving the way for the implementation of MIMO systems using only one RF front end.