Quadruple diversity: In radio communication, diversity transmission and reception in which four independently fading signals are used. Note: Quadruple diversity may be accomplished through the use of space, frequency, angle, time, or polarization multiplexing, or combinations of these.

For more information, check this links:

http://www.w8ji.com/polarization_and_diversity.htm

http://documents.mx/documents/358-hybrid-diversity.html

Alright, I messed up the hybrid diversity with the quadruple diversity, thank you very much sir for you clarification.