WCDMA-tukiaseman RF-järjestelmäsuunnittelu
Halme, Pekka Ville · Aaltodoc (Aalto University) · 2005
In this master's thesis a WCDMA RF transceiver was designed at system level. The designed RF block was embedded to a previous digital design to produce a fully working WCDMA transceiver board. The design was finally implemented and thorough measurements were conducted to validate the RF performance of the board. First a short introduction to the history and technical properties of UMTS air interface is given. Then the general RF requirements for a local area WCDMA transmitter and receiver are presented, based on 3GPP's UTRA FDD specification (V6.5.0). These specifications were used as a basis for the transceiver design. The transmitter and the receiver were implemented with previously designed RFIC circuits, which both use direct conversion architecture. Based on the RF specifications system calculations were made, from which the transceiver was designed and components were selected. Then the performance of the system with the selected components was estimated. Finally the designed transceiver PCB was manufactured. This circuit board was then measured in a real WCDMA base station environment to verify the actual performance. These measurements were made in compliance to 3GPP instructions, to the appropriate extent. Overall the measurements showed good performance, and in most cases the measured values exceeded the given requirements with several decibels. The only difficulties were with the maximum output power of the transmitter which was measured to be in average about 0.5 dB below the wanted value. The reason for this and suggestions for corrective measures are given in the end.