Title :
Suppressed carrier tracking when quadrature PN spreading
Author :
Jones, William W. ; Luecke, James R.
Author_Institution :
STM Wireless Inc., Irvine, CA, USA
fDate :
29 Sep-2 Oct 1996
Abstract :
The DS-SS CDMA standard for digital cellular communication (IS-95) employs quadrature PN spreading. Conventional carrier phase detectors using the two despread quadrature channels produce an untrackable error term proportional to the cross correlation between the inphase and quadrature PN codes. Tracking loops capable of circumventing this issue are defined and analyzed. These loops support QPSK throughput with carrier tracking performance characteristic of BPSK. Further, a new correlation loss is identified which is negligible for moderate spreading ratios but can be substantial for small ratios
Keywords :
cellular radio; code division multiple access; correlation methods; digital radio; maximum likelihood estimation; pseudonoise codes; quadrature phase shift keying; signal detection; spread spectrum communication; telecommunication standards; BPSK; DS-SS CDMA standard; IS-95; MAP parameter estimation; QPSK throughput; carrier phase detectors; correlation loss; cross correlation; despread quadrature channels; digital cellular communication; inphase PN codes; quadrature PN codes; quadrature PN spreading; spreading ratios; suppressed carrier tracking; tracking loops; untrackable error term; Binary phase shift keying; Communication standards; Detectors; Fading; Multiaccess communication; Phase detection; Quadrature phase shift keying; Telecommunication standards; Throughput; Tracking loops;
Conference_Titel :
Universal Personal Communications, 1996. Record., 1996 5th IEEE International Conference on
Conference_Location :
Cambridge, MA
Print_ISBN :
0-7803-3300-4
DOI :
10.1109/ICUPC.1996.562666
