back multiple meaning in Chinese

线孤复接

Switching context between users for example , switching from admin - user to another user , and then back multiple times has performance implications
在用户间进行多次上下文切换例如，从admin用户切换到另一个用户，然后又切换回来会带来性能隐患。
In the second part , the necessity of employing differential demodulation in rapid changing channel was explained , performance of multiple symbol detection of mdpsk and decision feed back multiple symbol detection were analyzed . then we present a new differential demodulation algorithm . the decision data is used to recover the carry phase . given the same observation intervals , this demodulation algorithm has almost the same performance , but the receiver is much more simplified
第二章首先指出了信道参数变化剧烈的情况下，采用差分解调的必要性；分析了多码元差分解调和数据判决反馈解调算法的性能和抑制噪声的能力；在此基础上提出了一种新的差分解调方案：利用判决数据辅助进行载波恢复，即在判决数据的辅助下，采用fir ( finantimpounsrespouns )结构对载波相位进行预测的一种算法，精心设计了该算法的实现结构。