Joern Thielecke’s scientific contributions

A multiuser base station receiver for CDMA mobile radio systems is proposed. It is based on a bank of conventional single-user DS-CDMA receivers connected to an adaptive linear combiner. The combiner takes into account the multiuser interference present in the CDMA system. It is the key component of the receiver: it allows one to improve the path delay estimation, to efficiently estimate the amplitudes of the propagation paths, and to benefit from interference cancellation. All this can be exploited to reduce bit error rates or increase system capacity. The receiver is suited for a flexible air interface with multiple and variable bit rates. Long random spreading codes for easy code management and handover may be employed

This paper focuses on a CDMA design study for future third-generation mobile and personal communication systems such as FPLMTS and UMTS. In the design study, a rigorous top down approach is adopted starting from the most essential objectives and requirements of universal third-generation mobile systems. Emphasis is laid on high flexibility with respect to the implementation of a wide range of services and service bit rates including variable rate and packet services. Flexibility in frequency and radio resource management, system and service deployment, and easy operation in mixed-cell and multioperator scenarios are further important design goals. The system concept under investigation is centered around an open and flexible radio interface architecture based on asynchronous direct-sequence CDMA with three different chip rates of approximately 1, 5, and 20 Mchip/s. The presented CDMA system concept forms the basis for an experimental test system (testbed) which is currently under development. This experimental system concept has been jointly established by the partners in the European RACE project R2020 (CODIT). The paper describes the radio transmission scheme and appropriate receiver principles and presents first performance results based on simulations