| Research Abstract |
Indoor radio communication systems with multiple transmit and receive antennas are studied. Theoretical join-optimization of transmit and receive ends are discussed for single carrier systems. Employment of OFDM scheme is also considered for the multiple antenna systems. Proposed error correction coding designed together with data mapping to signal-antenna space is found to have better performance than conventional SFBC in which coding and mapping are designed separately. The knowledge of the instantaneous features of in-door electro-magnetic environments is necessary for the design of radio systems, however, measurement is based on average power in former studies, which can not be used for the design of coding/mapping scheme for multiple antenna systems. In this study, we have build a measurement system, which can measure indoor propagation at multiple points in wide frequency range at the same time for long observation duration. As the results, features of indoor radio environment, such as time-frequency-space dependence of the propagation loss, are clarified. Anew benchmark, I.e., a measure of reliability, is also studied, and multiple antenna systems are evaluated with this measure. As the byproducts of this research, control method of adaptive array antenna with interference cancellation in CDMA systems, application of antenna beam control with interference cancellation for CDMA packet systems, and some consideration of amplitude fluctuations of OFDM systems are studied.
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