Mobile communication services have become popular due to the rapid popularization of cellular mobile telephones. In order to offer services to an increasing number of users and to upgrade services, the development of Third-Generation Mobile Telecommunication is required. Our proposed system utilizing W-CDMA enables high-speed variable data communications, uninterrupted hand-over between communication zones, doubling of subscriber capacity and reduction of operation costs. Various actions are being taken internationally toward the establishment of a global standard for the Third-Generation Mobile Telecommunication System, aiming at its practical application around AD 2000. The W-CDMA system has been adopted as the standard for Japan. We are developing experimental W-CDMA system equipment. For this development, many Field Programmable Gate Array (FPGA) devices and Digital Signal Processors (DSP) have been used to meet the changes of equipment specifications and system evaluation parameters. By developing customized Large-scale Integrated circuit (LSI) devices and high-speed DSP, a small-size portable phone and a compact visual phone have been realized. Also, high-density mounting of the signal processing parts has been done in the Base Transceiver Station (BTS). In the development of a Mobile Communication Controller Simulator (MCC-SIM), the developmental period has been shortened by using our ATM switching system (AD8700) and generic-use PBX (Pana EXA) in the proposed system. In this paper, the features of the W-CDMA system and the outline of the newly developed experimental equipment have been described.