中文摘要：

多入多出系统中的迭代树搜索（ITS）检测会遇到某些比特的对数似然比（LLR）无法确定的情况,需采用赋常数值的方法解决,但这会影响系统性能.为此,提出一种改进的软检测方案,通过合适地选取某些删除路径,将这些路径保留并延伸为全长路径,可以确保对每比特都能计算其LLR,并能提供可靠性高的LLR值.给出了路径选取的规则及延伸所选路径为全长的低复杂度方法.仿真结果表明,新算法与ITS算法相比具有更好的性能,并能使性能和复杂度达到较好的折中.

英文摘要：

Iterative tree search （ITS） is an efficient soft detection scheme in multiple-input multipleoutput （MIMO） systems. However, there often exists in ITS that log-likelihood ratio （LLR） values of some detected bits cannot be evaluated. Although it can be somewhat solved by setting the LLR magnitude for these bits to a constant value, the system performance would be degraded. To overcome this drawback, an improved soft detection scheme is proposed. The scheme ensures that the LLR value of each bit can be calculated and provides highly reliable LLR by appropriately choosing some discarded paths, retaining them and extending them to full-length paths. The rule of choosing suitable discarded paths is presented and the low-complexity approach of extending them to full length is given. Simulations show that the proposed algorithm can obtain better performance than ITS and can achieve good performance-complexity trade-off.