AGC scheme using characteristics of a received beacon signal particularly in a TDD-CDMA system

摘要

Automatic gain control (AGC) and synchronisation acquisition by a communication unit in a wireless communication system, e.g. a TDD-CDMA system such as the Universal Mobile Telecommunication System (UMTS) system, is described. AGC is performed using a downlink beacon function, for example a power level (PSBbeacon/SB). Also disclosed is Amplitude-equalising (limiting) performed as part of synchronisation acquisition and the use of separate AGC processes for different stages of synchronisation acquisition. One AGC process uses a peak power (P(k)) of a received signal over a frame. Another AGC process uses a peak power (P(k)) of a received signal over only a portion of a frame, the portion comprising an initial synchronisation code. Another AGC process uses measurements of a received signal (PSB0/SB(k)) taken in a downlink beacon timeslot. These processes tend to provide tolerance to a varying number of codes (M) transmitted on a timeslot-by-timeslot basis and robust initial synchronisation in the presence of strong uplink interference.