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Orthogonal frequency division multiplexing (OFDM) has become a prevalent and widespread technique for the broadcast and transmission of signals over wireless channels and has been adopted in many wireless standards. OFDM may be united with antenna arrays at the transmitter and receiver side to enhance the diversity gain and to improve the system competence on time-variant and frequency-selective channels,...
Cooperative relay has been an interesting research area for the past years as it promotes higher data rates and robust to wireless environment. IEEE Work Group initiated the use of relay stations in the IEEE 802.16e standard and it is called IEEE 802.16j. This paper proposed a multi-hop cooperative relay system with space-time codes (STC), with the integration of relay selection. In changing environment,...
In the IEEE 802.16d Orthogonal Frequency Division Multiplexing (OFDM) physical layer protocol, which provides the Space-Time Coding (STC) scheme to improve system performance, it is possible to get a better performance in resisting multipath fading and increasing bandwidth efficiency. However, in projects, using Multiple-Input Multiple-Output (MIMO) multiple-antenna technology is usually inconvenient...
This paper is focused on the study of layered space-time-frequency (LSTF) architectures with channel coding for orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) multiplexing systems for high speed wireless communications over a frequency-selective fading channel. In order to achieve the available spatial, temporal and frequency diversities, and also make the...
To obtain full benefits of the Alamouti space-time code design on a time-varying acoustic channel, the channel variation is decoupled into two parts: the gain, which is assumed to be constant over an Alamouti pair (two consecutive OFDM blocks), and the phase, which is not restricted in this manner, but allowed to vary from one block to another in a piecewise linear fashion. Under this model, the receiver...
The Golden Code (GC) is an Algebraic SpaceTime Code (ASTC) for MIMO systems, based on quaternion algebras. Thanks to the algebraic construction, the Golden codes are full-rank, full-rate and have the non-vanishing determinant property. These codes have been proposed for MIMO flat fading channels in order to increase the spectral efficiency and to maximize the coding gain. The purpose of this work...
The LS channel estimation was modified by implementing space and time code via introducing cyclic conjugate to both the information sequence and the pilot sequence in the time-domain. The bit error rate (BER) performance of orthogonal frequency division multiplexing (OFDM) and of single-carrier transmission with frequency-domain equalization (SC/FDE) with the new channel estimator in MIMO channels...
A multiple-input multiple-output (MIMO) single-carrier frequency domain equalization (SC-FDE) testbed which can emulate a practical broadband system is described. A scheme combining space-time transmit diversity with SC-FDE was implemented and evaluated on the testbed. After the hardware configuration, software algorithms incorporating the space-time block coding and decoding, synchronization, channel...
Based on the analysis of the technical principles and the system model of the MIMO and OFDM technologies, a simple DVB-T wireless communication system is constructed. The system is composed of transmitter, channel, receiver, and so on. Space-time coding is done in the transmitter, the signal is launched after OFDM modulation, and the process of the receiver is the inverse process of the transmitter...
Alamouti space-time coding is investigated in conjunction with OFDM modulation for high-rate underwater acoustic communications over time varying channels. The scheme's diversity gain is exploited using a low-complexity adaptive multichannel receiver. Performance is demonstrated using experimental data transmitted in a 10 kHz bandwidth over a 1 km shallow water channel south of the Martha's Vineyard...
In this paper, we present a new group iterative linear ZF receiver for a MIMO-OFDM system. The signals of all layers are firstly grouped and the signals in every group are detected by linear ZF detection method. The successive interference cancellation detection is applied between the different groups. Computer simulation results state the proposed algorithm achieves marked performance improvement...
In this paper, we derive a theoretical performance evaluation scheme of Kalman filter based channel tracking and data decoding for multiple-input multiple-output orthogonal frequency division multiplexed (MIMO-OFDM) communication systems that are based on orthogonal space-time block codes. The derivation is approximate, however, it is novel and demonstrated accurate for practical scenarios. Assuming...
In this study, we present a new reduced-complexity scheme for maximum-likelihood (ML) estimate of both carrier-frequency offset (CFO) and channel coefficients in multi antenna OFDM transmission, assuming that a training sequence is available. Our scheme is also capable to accommodate any space-time coded (STC) transmission. Moreover, to benchmark the performance of the proposed scheme, the Cramer-Rao...
The performance of a wireless communication system is analyzed considering multi-carrier OFDM with Multiple- Input-Multiple-Output (MIMO) wireless channel and Space-Time Block Coding (STBC). Bit Error Rate (BER) expression for MIMO-OFDM system without and with STBC is presented considering fading and timing jitter with QPSK, DPSK and DQPSK modulation schemes. The performance results are evaluated...
Recently, pre-fast Fourier transform (pre-FFT) combining has been introduced for space-time block-coded (STBC) orthogonal frequency division multiplexing (OFDM) systems. Despite the complexity reduction, the resultant signal-to-noise ratio (SNR) values of different subcarriers are often not balanced, and it limits the system performance. In this paper, we propose to use the max-min fair criterion...
Although the topic of multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) over different fading channels is well investigated, but its exact closed form symbol error rate (SER) expression employing orthogonal space-time block codes (OSTBCs) over uncorrelated Nakagami-m fading channels for M-ary phase shift keying (M-PSK) is still not available. The closed form expressions...
This work presents a new blind multiuser equalization strategy for Time Reversal Space Time Block Coding (TRSTBC) signals transmitted over a dispersive MIMO channel. The adaptation is based on forcing the probability density function (PDF) of the equalizer output to match the desired PDF of corresponding source symbols. In the proposed approach, the PDFs are estimated by means of the Parzen window...
We present the FPGA implementation of a MIMO and cooperative OFDM physical layer transceiver. Our transceiver is designed to support multiple antenna configurations, including SISO (single-antenna), receive switching diversity, transmit diversity using Alamouti's space-time block code and 2??2 spatial multiplexing. It also supports a fully-distributed physical layer cooperation scheme which allows...
A 64-state 16-QAM space-time trellis code (STTC), which uses two transmitting antennas, is proposed and applied to a 2??2 MIMO-OFDM system for outdoor mobile transmission in the 800-MHz band. Although STTCs have been analyzed theoretically and the error performances have been simulated by many researchers, experimental results have rarely been reported. Therefore, we evaluated the performance of our...
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