CDMA AIR INTERFACE FOR RADIO LOCAL LOOP SYSTEM

摘要

The capacity of a code division multiple-access (CDMA) net used for a radio loca l loop system can be increased by exploiting the fixed nature of subscriber statio ns (3). Orthogonal spreading codes are used for both the forward (12,16) and reverse lin ks (17) and the transmissions from the subscriber stations (3) are adjusted so that signals received at the base station (1) from the subscriber stations (3) are synchronised with respect to their spreading codes to within a chip period. Accu rate synchrinisation, time control and carrier frequency error compensation of the co de division multiple access transmission from multiple subscriber stations (3) redu ces the level of multiple access interference experience on the reverse link (17) (f rom subscriber to base station) which is normally the principal limiting factor on t he capacity of a system employing CDMA. FIG. 1.