| 摘要: | 研究期間：10108~10207;Recently we propose a novel differential encoding which uses a look-up table instead of a rule. All possible differential encoders can be implemented by this differential encoder which uses a look-up table. The proposed differential encoder provides significant gain over existent differential encoders, either for minimum noncoherent distance or for bit error rates. In our most recent research, we obtain further results on differential encoding by a table, including various new modulation, multiple-symbol differential encoding, differential detection by a trellis and differential encoding concatenated with trellis coding, which improve the error performance. Besides, we apply the idea of differential encoding by a table to space-time codes. Compared with conventional differential space-time modulation (DSTM), the proposed new definition of DSTM avoids the problem of constellation expansion while has similar bit error rates. Multiple-symbol differential encoding proposed recently is a kind of differential encoding for multiple-symbol differential detection. This method is novel since it has not been proposed before. We have proposed the definition and give an example. We will study multiple-symbol differential encoding, including various modulation for various coherence time, differential detection by a trellis for multiple-symbol differential encoding and multiple-symbol DSTM. However, multiple-symbol differential encoding does not consider channel coding. In this project, we will study multiple-symbol differential encoding with redundant bits (or symbols), which uses a signal constellation with more signal points and provides better bit error rates. This 3-year project will research multiple-symbol differential encoding based on my research experience of noncoherent modulation and demodulation. In the first year, we will design codes and do code searches. In the second year of this project, besides further improve the results of the first year, we will use block-coded modulation. That is, re-design noncoherent block-coded modulation we proposed before. In the last year, we will continuously improve the results of the first two years, and use trellis-coded modulation. That is, re-design noncoherently noncatastrophic trellis-coded modulation we proposed recently. |
