Title :
Orthogonality of UMTS codes in indoor channels
Author :
Webber, J.L. ; Beach, M.A. ; Hunukumbure, M. ; Canagarajah, C.N.
Author_Institution :
Univ. of Bristol, UK
Abstract :
UMTS (Universal Mobile Telecommunications System) spreading codes are only truly orthogonal in the absence of multipath delay and time offsets. In all practical channels the loss of orthogonality will result in the generation of non-zero cross-correlation products that can compromise the error performance of code division multiple access (CDMA) systems. The practical level of cross-correlation produced in the uplink of multiuser applications at the base-station site and the effect of this interference on the RAKE receiver is investigated by means of wideband dual polar channel measurements from a field trials campaign, taken within the UMTS time division duplex (TDD) uplink (1910-1915 MHz). The results showed that 75% of the measurements in an indoor channel had normalised correlations less than 0.25.
Keywords :
3G mobile communication; UHF radio propagation; codes; correlation methods; indoor radio; multipath channels; multiuser channels; radio links; radio receivers; spread spectrum communication; 1910 to 1915 MHz; CDMA systems; DS-CDMA; RAKE receiver; TDD uplink; UHF; UMTS codes orthogonality; UMTS spreading codes; Universal Mobile Telecommunications System; base-station site; code division multiple access; direct sequence CDMA; error performance; field trials; indoor channel measurements; interference; multipath delay; multiuser applications; nonzero cross-correlation products; normalised correlations; time division duplex uplink; time offsets; wideband dual polar channel measurements;
Conference_Titel :
3G Mobile Communication Technologies, 2002. Third International Conference on (Conf. Publ. No. 489)
Print_ISBN :
0-85296-749-7
DOI :
10.1049/cp:20020379
