We consider the inter-antenna separation in a distributed antenna array. We introduce a new separation constraint with respect to the signalling wavelength, which equals the chip wavelength in DS-CDMA systems and the symbol wavelength in non-spread systems. This constraint ensures the phases of the frequency responses are exercised over 2.. in the baseband channel matrix. The diverse phases provide a better channel matrix for signal detection. The multiuser performance improvement due to this constraint has been named as the Signalling Wavelength Antenna Placement (SWAP) gain.
Citation:
Guangran Zhu, Brent R. Petersen, Bruce G. Colpitts, "Signalling Wavelength in an Antenna Array for Space-Time Wireless over LOS Channels," cnsr, pp.69-73, 3rd Annual Communication Networks and Services Research Conference (CNSR'05), 2005