The impact of radio propagation predictions on urban UMTS planning

This investigation outlines the importance of accurate radio propagation predictions in the planning for UMTS radio networks. The UMTS radio technology based on variable spreading DS-CDMA techniques is flexible but complex. The sensitivity of a UMTS radio network to the radio environment and traffic conditions is well publicized but rarely quantified. Theoretical analysis and commercial implementation of CDMA cellular systems also tend to show that radio network planning, simplified on one hand because of the lack of frequency planning, could be cumbersome due to difficulties linked to the so-called cell breathing effect. Since this effect is related to the traffic conditions and the radio propagation environments, the more accurate the coverage predictions are, the closer the expected performance will be from the measured performance. To quantify the advantage of accurate radio coverage predictions a case study was undertaken for a UMTS radio network planning in a 5 km² area of Paris (France). This study in an urban environment concludes that a conventional propagation model could lead to erroneous planning with less than expected quality of service, unacceptable interference, and more base stations than necessary. An accurate ray-tracing model integrated in an UMTS-capable planning tool allows the radio network designer to reach optimal levels for the base station deployment and configuration while meeting the expected service level requirements