基于BPSK-CSK的电文调制与解调算法

针对对导航信号信息传输速率有更高要求的信号，如精密定位信号，提出二进制相移键控-码移键控(BPSK-CSK)联合调制方法，以解决传统的码移键控(CSK)调制信号在接收端对相关器资源需求量大、解调计算复杂度高的问题.本文方法将分组调制的电文再分为极性位与码相位，使得接收端由原本通过相关求和进行解调，转变为通过较少相关求和运算与子码匹配两步完成电文解调，减少了接收机解调电文所需相关器的数量并降低参与运算的数据量级.所提方法在极性位数为1或2时，与传统CSK相比，可以实现在电文解调误比特性能损耗可忽略不计的情况下，计算复杂度降低为原来的50%或25%.当极性位数大于2时，该方法以解调性能为代价降低计算复杂度，但此时结合信道编码，BPSK-CSK仍可实现等计算复杂度下的误比特率降低.

Research on BPSK-CSK message modulation and demodulation algorithm

For signals that have higher requirements on the information transmission rate, such as precision positioning signals, a combined binary phase shift keying-code shift keying (BPSK-CSK) modulation method is proposed to solve the problem of the high demodulation computational complexity of the traditional code shift keying (CSK). This method subdivides the modulated message into polar bits and code phase bits, so that the receiver converts demodulating message by correlating and summation into two steps to complete the message demodulation through less times of correlating summation and subcode matching. It reduces the number of correlators required for the receiver to demodulate the message and reduces the data magnitude involved in the operation. When the number of polar bits is 1 or 2, compared with the CSK, the performance of bit error rate is negligible, and the computational complexity is reduced to 50% or 25% of the computational complexity of the original method. When the number of polar bits is greater than 2, the computational complexity will be reduced at the expense of the bit error rate, but at this time, combined with the error-correcting coding, BPSK-CSK can still reduce the bit error rate under the same computational complexity.