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需求之一。为满足这一要求以及其他与性能、覆盖范围、容量和可靠性相关的高标准，众多研究提出了在演进中的4G无线通信中，结合多种技术（如多输入多输出（MIMO）无线技术与正交频分复用（OFDM））的系统开发方案。我们提出的系统基于2x2 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）以及OFDM技术。OFDM可通过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）。我们开发的模型中采用了SFBC。SFBC相比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则将两个调制符号编码到同一OFDM符号的两个子载波上；因此，编码在频域中执行。我们的解决方案旨在展示空频分组编码（SFBC）方案的性能分析，通过在2x2 MIMO信道上使用4 QAM、16 QAM和64 QAM调制进行LTE下行链路传输，提高接收端的信噪比（SNR）并降低误码率（BER），同时考虑不同的无线信道环境。在本研究中，我们实现了一个分析工具，用于评估使用两个发射天线和两个接收天线的SFBC-OFDM性能，并将平均SNR分析视为描述SFBC在3GPP长期演进（LTE）系统MIMO信道中性能的充分统计量。