Abstract: A slotted communication mode employed in a wireless code division multiple access (CDMA) communication system includes slotted frames interspersed among normal frames, each slotted frame containing a slot during which a measurement of signal quality of transmission at a different candidate operating frequency is made by the mobile station, a leading frame portion preceding the slot, and a trailing frame portion succeeding the slot. In order to mitigate an increase in bit error rate (BER) as a result of use of the slotted mode the spreading factor (SF) of data in the leading and trailing frame portions is set to a value which is greater than that of data in the normal frames. The increase of spreading factor of data in these frame portions may be accompanied by an increase in power level therein, as a further BER mitigating factor.