| dc.description.abstract | In this dissertation, we aim to study on three topics: adaptive demodulation (ADM) system, block-wise differential encoding and trellis searches for noncoherent block codes.
In Chapter 2, we propose a new detector of adaptive demodulation (ADM) for rateless code over the additive white Gaussian noise (AWGN) channel or the quasi-static fading channel. For 16-DPSK, we show that the proposed detector is able to find bits with the largest joint probability, and equivalent to the detector in [2]. Besides, the error performance of ADM is compared with conventional DPSK by decision boundaries. For 16-DAPSK, the proposed detector has better error performance than the detector in [2], and also outperform 16-DPSK except that the only one bit is recovered. For 16-PSK, the proposed detector has the same error performance as the detector in [1]. For 16-QAM, the proposed detector has better error performance than the detector in [1] except that three bits are recovered. In addition, we research ADM using multiple-symbol differential detection (MSDD) and conclude that MSDD is not suitable for ADM.
In Chapter 3, we propose a block-wise differential encoding method for noncoherent block-coded 16TAPSK and 16QAM. By this method, the first symbol of the transmitted codeword is the same as the last symbol of the previously transmitted codeword, so it can be omitted. We analyze the minimum noncoherent distance of noncoherent block-coded QAM/TAPSK, and also modify the bit labeling of 16QAM and 16TAPSK to achieve better error performance for noncoherent block-coded QAM/TAPSK.
In Chapter 4, we propose to use noncoherent trellis codes as noncoherent block codes. Trellis codes for different number of trellis states are searched. Besides, we compare the search trellis codes with codes of noncoherent block-coded modulation over various rate. The search codes can offer various trellis states for various rates. | en_US |