有限长度编码的误比特率性能极限

Bit error rate limit for finite length codes

本文从码空间子集分解的角度出发，得到了加性高斯信道中二进制有限长度编码的误比特率下界。此极限表明码长大约在１０００ｂｉｔ以上时，好码的编码增益随码长增加的速度极为缓慢，并且在编码效率大约高于０．８时，编码增益也将急剧下降。

The BER lower limit of the binary finite-length coding for AWGN channel is derived through the code space subdivision.The limits reveals that the further increase of code length can only bring out an insignificant increase of code gain if the length is about 1000bit or longer. In addition, the code gain will decrease dramatical- ly when code rate is over 0. 8.