Design and implementation of a wide-band real-time mobile channel emulator

In this paper, a new wide-band mobile channel emulator for the CODIT projec t is designed and implemented. The UMTS code-division testbed (CODIT R2020) is a research project within the European RACE-II program set up by the Co mmission of the European Community. Our goal is to be able to simulate in t he laboratory, in real time, the multipath propagation found in the mobile radio channel. As code-division multiple access (CDMA) is the access techni que within the CODIT project, it was realized that the channel emulator mus t have simultaneously good delay resolution between propagation paths and l ong duration of the impulse response. These considerations led to a very fl exible channel emulator specifically designed to host the new wideband chan nel models developed within the CODIT project. Our emulator features three independent inputs and two outputs, up to 20 complex propagation paths, 10- MHz radio frequency (RF) bandwidth, a delay resolution of 50 ns, and a maxi mum duration of the channel impulse response of 80 mu s. Starting with an e xplanation of the global structure of the new channel emulator, we derive t he optimum design of the interpolation procedures and present the main impl ementation issues arising from our initial architecture. Finally, we report the results of the laboratory tests of the first prototype of the channel emulator.