The present invention is directed to systems and methods for measuring the
interference for computation of signal to interference ratio (SIR) in DSSS
CDMA cellular communication systems, by selectively using a transmission
gap in one of the control channels. A specific example embodiment is
directed to the computation of the SIR in a system, such as the 3GPP
system, where PCCPCH data is multiplexed with SCH data in the downlink
from the base station. At the mobile unit, once the PCCPCH is located in
the received communication signal, the receiver measures the traffic
interference in a chip period in the PCCPCH channel that corresponds to an
interval where there is a transmission gap in the PCCPCH data. This gap is
provided in the 3GPP system for permit the transmission of primary and
secondary SCH data. The SIR is readily determined using the measured
interference in the transmission gap.
