切比雪夫距离度量下多重置换码的新构造方法

针对闪存系统出现的“强度有限错误”以及等级调制置换码信息存储率不够高的缺点，通过对具有相同最小距离的多重置换集进行直积运算，提出了切比雪夫距离度量下可纠正这种错误的正则多重置换码的一种简单构造方法．同时，通过对简单正则多重置换码进行投影运算而得到最小距离互不相同的多重置换集，提出了基于多重置换集直积运算的正则多重置换码的一般构造方法．与现有的切比雪夫距离度量下多重置换码构造方法相比较，所提出的基于直积运算的多重置换码构造方法更加直观．通过一些计算实例验证了所提出的正则多重置换码构造方法的正确性．

New construction methods for multipermutation codes under the Chebyshev distance metric

For the limited-magnitude errors occurring in a flash memory system and the disadvantage that the information rates of rank-modulation permutation codes are not high enough, a simple construction method for regular multipermutation codes that can correct these errors is proposed by using the direct product operation on multipermutation sets which have the same minimum distance under the Chebyshev distance metric. Moreover, by using the projection operation on the known simple regular multipermutation codes, the multipermutation sets with different minimum distances are obtained. Based on the direct product of these multipermutation sets, a generalized construction method for regular multipermutation codes is proposed. Compared with the existing construction methods of multipermutation codes under the Chebyshev distance metric, the proposed construction methods of multipermutation codes based on direct product operation are more intuitive. Some calculation examples are provided to verify the validity of the proposed construction methods.