Performance Characterization of WCDMA Dedicated Traffic Channels Based on Node B Transmit Power and Pilot Measurements

In UMTS the quality of a dedicated radio bearer is given in the target BLER of the DTCH. The requirements for a DTCH to meet the wanted average BLER strongly depend on the data rate. The larger the data rate the more transmit power is typically needed to achieve the desired quality. Depending on the RF environment the average BLER can be typically met if the average signal to noise and interference ratio Es/Nt achieves a target value, which, of course, depends on the data rate. Determination of Es/Nt requires measuring after the Rake received. Such measurements may not be accessible in all measurement equipment, commonly used during cell planning process. Another difficulty is that the cell selection/reselection as well as handover thresholds are usually given in terms of Ec/I0 measured on the pilot channel P-CPICH. If the pilot coverage and the DTCH coverage are planned in different metrics it is difficult to guarantee a certain service in all areas of pilot coverage. Thus it is desirable to express the DTCH performance also in terms of pilot Ec/I0. The goal of this paper is to derive relations between the quality of a radio bearer in terms of BLER of the DTCH and measurements that can easily be obtained by standard equipment like EC/I0 and TSSI.