Tatsuya Uchiki

Carrier slip compensating time diversity scheme for helicopter satellite communication systems

This paper proposes a novel signal transmission scheme for helicopter-satellite communications. The proposed scheme is based on time diversity, and combined with a novel algorithm to suppress an influence of carrier phase slip. In the proposed scheme, carrier phase slip is detected in cross correlation processing of the received signal, and is effectively suppressed. The proposed scheme thus makes it possible to employ coherent phase shift keying (CPSK) modulation to achieve bit error rate (BER) performance superior to that of differential phase shift keying (DPSK) modulation even in the low carrier-to-noise power ratio (CNR) environment.

Viterbi decoding with per-survivor processing of adaptive array antenna

The adaptive array technique is expected to reduce the multipath fading that causes degradation of bit error rate (BER) performance in the future broadband wireless systems. Some prior works proposed the joint schemes of the adaptive array and the equalizer technique, however few reports discuss the combination of a forward error correction scheme and the adaptive array. We propose a novel combination scheme of Viterbi decoding and the adaptive array based on a per-survivor processing. In the proposed scheme, each state of the Viterbi decoder has array weights that are adaptively updated along with the surviving paths. The proposed scheme has a coding effect on the weight estimation without decoding delay and estimates the accurate weights. We evaluate the performance of the proposed scheme by computer simulation. The results of computer simulation show that the proposed scheme provides good tracking performance to the interference and good performance in terms of BER under the severe low carrier-to-interference power ratio (CIR) environments.