Overloaded Array Processing

An antenna array is overloaded when the number of co-channel signals in its operating environment is greater than the number of its elements. Conventional space-time array processing for narrow-band signals fails in overloaded environments. Overloaded array processing (OLAP) exploits additional signal properties such as the finite-alphabet property and signal excess-bandwidth. Three approaches to signal extraction in overloaded environments were proposed in [1]. These different signal extraction techniques include the use of MMSE interference rejection filtering embedded in a successive interference cancellation (SIC) architecture, embedding of a reduced-state maximum aposteriori probability (RS-MAP) algorithm in a similar SIC architecture and the application of an energy focusing transform (EFT) with spatially reduced search joint detection (SRSJD).

The use of Maximum Likelihood Sequence Estimation (MLSE) in the presence of unknown channel parameters with reference to OLAP is investigated in [2].

References 

[1] James Hicks, Novel Approaches to Overloaded Array Processing,” Ph.D. Dissertation, Virginia Tech, 2003.

[2] Maruf Mohammed, “Blind Acquisition of Short Burst with Per-Survivor Processing (PSP),” MS Thesis, Virginia Tech 2002.

[3] Hicks, J.; Bayram, S.; Tranter, W.H.; Boyle, R.J.; Reed, J.H. Overloaded array processing with spatially reduced search joint detection,” IEEE Journal on Selected Areas in Communications, Volume: 19 , Issue: 8 , Aug. 2001 Pages:1584 – 1593

[4] Hicks, J.E.; Tsai, J.; Reed, J.H.; Tranter, W.H.; Woerner, B.D., Overloaded array processing with MMSE-SIC,” Vehicular Technology Conference, 2002. Volume: 2, 6-9 May Pages: 542 - 546