Abstract It is considered a technique of mutual application of multi-antenna MIMO systems and multiplexing with orthogonal frequency division of OFDM channels for current-technology systems of wireless communication of special application. There are defined areas of prior application of time and frequency variant of diverse signals transmission according Alamouti principle for wireless channels with limited frequency and energy resources. It is shown that application of fixed precoding matrix of Walsh–Hadamard to outgoing symbols of space-frequency Alamouti coder allows to increase stability of SFBC-OFDM method to frequency selectivity of a channel without system complication. It is analyzed a conception of index modulation of OFDM-IM subcarriers. There are demonstrated advantages of Dual-Mode OFDM-IM with optimized signals ensembles on a basis of BPSK, QPSK and 16-QAM. It is proposed a novel signal-code construction (SCC) with join of dual-mode index modulation of OFDM subcarriers, orthogonal space-frequency block coding with Alamouti kernel and Walsh–Hadamard coder WH-SFBC-DM-OFDM-IM. Such method in contrast to classic SFBC-OFDM method allows to increase simultaneously spectral and energy efficiency of information transmission systems in conditions of frequency-time selectivity of communication channel. Proposed method is completely invariant to frequency selectivity in case of BPSK application and partially invariant in case of application of QPSK and 16-QAM. The simulation results show that noise immunity of such SCC is enough better in compare with the other methods due to providing of identity of space-frequency word at duration of OFDM symbol. The method is advisable to use for provision of high-quality communication with high-dynamic ground objects, pilotless vehicle and the other aircrafts in conditions of critical decrease of channel noise prtection which appears in case of influence of radio countermeasures systems.

中文翻译：

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使用双模索引调制 OFDM 的空频块编码和提高信道频率选择性的稳定性

摘要 它被认为是一种多天线MIMO系统相互应用和OFDM信道正交频分复用的技术，适用于当前特殊应用的无线通信技术系统。根据 Alamouti 原理，对于具有有限频率和能量资源的无线信道，存在不同信号传输的时间和频率变体的在先应用的定义领域。结果表明，将 Walsh-Hadamard 的固定预编码矩阵应用于空频 Alamouti 编码器的输出符号可以提高 SFBC-OFDM 方法对信道频率选择性的稳定性，而不会导致系统复杂化。分析了OFDM-IM子载波索引调制的概念。在 BPSK、QPSK 和 16-QAM 的基础上，具有优化信号集合的双模 OFDM-IM 已被证明具有优势。提出了一种新的信号码结构 (SCC)，其中结合了 OFDM 子载波的双模索引调制、使用 Alamouti 内核的正交空频块编码和 Walsh-Hadamard 编码器 WH-SFBC-DM-OFDM-IM。与经典的SFBC-OFDM方法相比，这种方法允许在通信信道的频率-时间选择性条件下同时提高信息传输系统的频谱和能量效率。所提出的方法在应用 BPSK 的情况下对频率选择性完全不变，在应用 QPSK 和 16-QAM 的情况下部分不变。仿真结果表明，由于在OFDM符号的持续时间内提供了空频字的标识，这种SCC的抗噪能力与其他方法相比足够好。该方法适用于在无线电对抗系统影响的情况下出现的信道噪声保护严重降低的情况下，提供与高动态地面物体、无人驾驶飞行器和其他飞行器的高质量通信。