Molecular communications via diffusion (MCvD) is a popular research area thanks to its potential applications, mostly in nano communications. Despite many recent publications on MCvD, the studies on error correction/channel coding for molecular communications are limited. Low weight channel codes have been proposed in the literature due to their energy efficiency and ISI mitigation. We add the constant weight condition on top of being low weight for MCvD channel codes, since the information of all codewords having the same weight can be utilized at the receiver. Moreover, encoding simplicity of Constant Low Weight Codes (CLWC) compared to the conventional coding schemes makes them appealing for MCvD, considering nanodevice limitations. This paper focuses on the decoding strategies for CLWC at the receiver side. Threshold and sorting-based decoders for molecular communications are reviewed and two different novel decoding mechanisms for CLWC are proposed. Iterative sorting decoder is a decision-feedback heuristic method that iteratively calculates the ISI from a better estimation at each step. The second proposed method is the super trellis decoder, which is a maximum likely sequence estimator. Outer states in the trellis denote the number of total weights in a sequence, whereas inner states represent the memory of the ISI channel. Both proposed methods increase the communication quality significantly by lowering transmission error probabilities. Simulation comparisons with existing methods show performance superiority of the proposed algorithms. Depending on the capability of the receiver and the availability of the channel state information, both methods are viable to be used with CLWC.

由于扩散的分子通讯（MCvD）具有潜在的应用前景，因此它是一个受欢迎的研究领域，主要是在纳米通讯领域。尽管最近有许多关于MCvD的出版物，但有关分子通信的纠错/信道编码的研究仍然有限。由于低权重信道代码的能量效率和ISI缓解，它们已在文献中提出。由于MCvD信道码的权重较低，因此我们添加了恒定权重条件，因为具有相同权重的所有码字的信息都可以在接收器处使用。此外，考虑到纳米器件的局限性，与常规编码方案相比，恒定低权重代码（CLWC）的编码简单性使其吸引MCvD。本文重点介绍了接收方CLWC的解码策略。审查了基于阈值和排序的分子通信解码器，并提出了两种不同的新颖的CLWC解码机制。迭代排序解码器是一种决策反馈启发式方法，可从每个步骤的更好估计中迭代计算ISI。提出的第二种方法是超级网格解码器，它是最大可能的序列估计器。网格中的外部状态表示序列中总权重的数量，而内部状态表示ISI通道的内存。两种提出的方​​法都通过降低传输错误概率来显着提高通信质量。与现有方法的仿真比较显示了所提出算法的性能优势。根据接收器的能力和信道状态信息的可用性，