For a general class of constant-energy trellis-coded modulation schemes with 2 ? states, necessary and sufficient conditions to guarantee that a maximum-likelihood sequence estimator can decode each symbol with a fixed delay of ? symbols are derived. Additive white Gaussian noise is assumed. MSK is a special case that belongs to the family of modulation schemes with ? = 1. It is shown that when these conditions are met, the minimum squared Euclidean distance is upper bounded by 4 E s , where E s is the signal's energy per interval. Necessary and sufficient conditions to achieve the upper bound are given and it it shown that these conditions are met if and only if the trellis-coded modulation scheme can be implemented as pulse amplitude modulation using a pulse that extends over ? + 1 symbols. Signals that achieve this upper bound and maximize the power within a given bandwidth are found. The bandwidth efficiency of such schemes is significantly higher than that of MSK.
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机译:对于一般类别的具有2?的恒定能量网格编码调制方案。状态,必要条件和充分条件,以确保最大似然序列估计器可以以固定的延迟?解码每个符号符号被导出。假定存在加性高斯白噪声。 MSK是一种特殊情况,属于带有?的调制方案系列。 =1。表明满足这些条件时,最小平方欧几里德距离的上限是4 E s,其中E s是每个间隔的信号能量。给出了达到上限的必要和充分条件,并且表明,只有当网格编码调制方案可以实现为使用延伸超过π的脉冲进行脉冲幅度调制时,这些条件才能得到满足。 +1个符号。找到达到此上限并在给定带宽内最大化功率的信号。这种方案的带宽效率明显高于MSK。
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