M进制调制系统发送<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/b2feddcaf5aa42a286c86d9280202527.png?x-oss-process=image/sharpen,200"/>中的某个星座点<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/88214135b05c42528dee2d7359a689ba.png?x-oss-process=image/sharpen,200"/>，经过信道传输后收到<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/8cc77f97998e4b87bb37eca07abf96d3.png?x-oss-process=image/sharpen,200"/>。后验概率<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/7f4c5b32354145669f726646c1fc0bc7.png?x-oss-process=image/sharpen,200"/>、似然函数<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/e2c66382c11742cd875d939bbb21755e.png?x-oss-process=image/sharpen,200"/>、先验概率<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/4c35bf591ab240afb920ac2f03532067.png?x-oss-process=image/sharpen,200"/>之间的关系是_____。