High data rates are one of the most prevalent requirements in current mobile communications. To cover this and other high standards regarding performance, increasing coverage, capacity, and reliability, numerous works have proposed the development of systems employing the combination of several techniques such as Multiple Input Multiple Output (MIMO) wireless technologies with Orthogonal Frequency Division Multiplexing (OFDM) in the evolving 4G wireless communications. Our proposed system is based on the 2x2 MIMO antenna technique, which is defined to enhance the performance of radio communication systems in terms of capacity and spectral efficiency, and the OFDM technique, which can be implemented using two types of sub-carrier mapping modes: Space-Time Block Coding and Space Frequency Block Code. SFBC has been considered in our developed model. The main advantage of SFBC over STBC is that SFBC encodes two modulated symbols over two subcarriers of the same OFDM symbol, whereas STBC encodes two modulated symbols over two subcarriers of the same OFDM symbol; thus, the coding is performed in the frequency domain. Our solution aims to demonstrate the performance analysis of the Space Frequency Block Codes scheme, increasing the Signal Noise Ratio (SNR) at the receiver and decreasing the Bit Error Rate (BER) through the use of 4 QAM, 16 QAM and 64QAM modulation over a 2x2 MIMO channel for an LTE downlink transmission, in different channel radio environments. In this work, an analytical tool to evaluate the performance of SFBC - Orthogonal Frequency Division Multiplexing, using two transmit antennas and two receive antennas has been implemented, and the analysis using the average SNR has been considered as a sufficient statistic to describe the performance of SFBC in the 3GPP Long Term Evolution system over Multiple Input Multiple Output channels.

翻译：高数据速率是当前移动通信中最普遍的要求之一。为了满足这一需求以及覆盖范围、容量和可靠性等其他高标准，大量研究提出了在演进中的4G无线通信中，结合多输入多输出（MIMO）无线技术与正交频分复用（OFDM）的系统开发方案。本系统基于2×2 MIMO天线技术（旨在提升无线通信系统在容量和频谱效率方面的性能）与OFDM技术，其中OFDM可采用两种子载波映射模式实现：空时分组编码（STBC）和空频分组编码（SFBC）。我们开发的模型采用了SFBC。SFBC相对于STBC的主要优势在于，SFBC将两个调制符号编码到同一OFDM符号的两个子载波上，而STBC则同样将两个调制符号编码到同一OFDM符号的两个子载波上，但编码是在频域中完成的。本方案旨在通过采用4 QAM、16 QAM和64 QAM调制在2×2 MIMO信道上的LTE下行链路传输，展示空频分组编码方案的性能分析，从而提高接收端信噪比（SNR）并降低误码率（BER）。本文实现了一种使用两副发射天线和两副接收天线评估SFBC-OFDM性能的分析工具，并将基于平均SNR的分析视为描述3GPP长期演进系统中SFBC在多输入多输出信道上性能的充分统计量。