Binary-Tree Encoding for Uniform Binary Sources in Index Modulation Systems
Binary-Tree Encoding for Uniform Binary Sources in Index Modulation Systems
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DOI：
10.1109/jstsp.2019.2914531
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发表时间：
2019-01
影响因子：
7.5
通讯作者：
J. Coon;Mihai-Alin Badiu;Ye Liu;Ferhat Yarkin;Shuping Dang
中科院分区：
文献类型：
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作者：
J. Coon;Mihai-Alin Badiu;Ye Liu;Ferhat Yarkin;Shuping Dang
针对采用子载波索引调制（IM）的正交频分复用（OFDM）系统，研究了比特到模式映射和功率分配方案的设计问题。我们假设二进制源向模式映射器传送独立的、均匀分布的比特流，这引入了对模式传输概率分布的约束，该约束可以使用二叉树形式主义来量化。在此约束下，我们承担的任务，最大限度地提高可实现的速率在发射机的信道知识的可用性。优化变量是模式概率分布（即，比特到模式映射）和分配给活动子载波的发射功率。为了解决这个问题，我们首先考虑放松的问题，其中允许模式概率在区间[0，1]中取任何值，但要满足和概率约束。我们开发（近似）最优解的放松问题，通过使用新的界限和渐近结果，然后使用一种新的启发式算法，项目的放松解决方案的约束问题的可行集上的一个点。数值分析表明，这种方法是能够实现最大的互信息在低和高信噪比制度的放松的问题，并提供了显着的好处，可实现的速率相对于传统的OFDM-IM基准。
The problem of designing bit-to-pattern mappings and power allocation schemes for orthogonal frequency-division multiplexing (OFDM) systems that employ subcarrier index modulation (IM) is considered. We assume that the binary source conveys a stream of independent, uniformly distributed bits to the pattern mapper, which introduces a constraint on the pattern transmission probability distribution that can be quantified using a binary tree formalism. Under this constraint, we undertake the task of maximizing the achievable rate subject to the availability of channel knowledge at the transmitter. The optimization variables are the pattern probability distribution (i.e., the bit-to-pattern mapping) and the transmit powers allocated to active subcarriers. To solve the problem, we first consider the relaxed problem where pattern probabilities are allowed to take any values in the interval [0, 1] subject to a sum probability constraint. We develop (approximately) optimal solutions to the relaxed problem by using new bounds and asymptotic results, and then use a novel heuristic algorithm to project the relaxed solution onto a point in the feasible set of the constrained problem. Numerical analysis shows that this approach is capable of achieving the maximum mutual information for the relaxed problem in low- and high-SNR regimes and offers noticeable benefits in terms of achievable rate relative to a conventional OFDM-IM benchmark.