| 摘要 |
The invention discloses methods for modulating and demodulating wireless laser communication. The method for modulating comprises the following steps that 1, the information source data to be modulated is divided into two parts; 2, the first part of data adopts 2m-step pulse-position modulation; 3, the number N of polarization state directions of multi-system polarization modulation is determined; 4, 2n polarization state combinations are selected from the total Nk polarization state combinations of k polarization state information, and establish a one-to-one correspondence relational table with n bits of binary data; and 5, according to the relational table, one polarization state combination which corresponds to the n bits of binary data in the current second part of data is looked up, and the k polarization state information in the step 2 is modulated one by one according to the k polarization state information in the polarization state combinations. The obtained modulation signal comprises not only the pulse-position information which reflects the first part of data but also the pulse polarization state information which reflects the second part of data, and under the same bandwidth, the method for modulating carries more data compared with a pulse-position modulation (PPM) method. |
