Analysis of IPDL patterns for increased signal detection probability in UMTS

To support mobile location services in UMTS systems, idle period downlink (IPDL) techniques have been proposed to avoid the near-far effect in CDMA systems and thus to facilitate the measurement of time difference of arrivals. In this paper the effects of the idle period pattern and variable coherent and non-coherent integration lengths on the detection of signals from distant base stations are evaluated theoretically under some simplifying assumptions and by simulation. The proposed clustered idle period patterns are assessed and shown to outperform regular patterns in certain conditions.