Using millimeter wave (mmWave) transmission for massive multiple input output (MIMO) system can improve performance and effectively reduce the size of antennas array. However, A wideband beamformer design is needed to take advantage this channel. In paper, a downlink multi-user MIMO orthogonal frequency division multiplexing (MIMO OFDM) mmWave communications proposed. Each subcarrier channel be...

In fiber-optic transmission system, transmission capacity and distance of optical signal are always an important consideration factor to improve the performance of the fiber-optic transmission system. The driving force motivating the use of multichannel optical systems is the enormous bandwidth available in optical fiber. A higher speed signals will be a combination of many lower-speed signals,...

We propose two low complexity adaptive step-size mechanisms based on the normalised orthogonal gradient algorithm for frequency-domain equalisation in orthogonal frequency division multiplexing (OFDM) systems. These algorithms are derived from employing a mixed-subcarrier exponentially weighted least squares criterion. Two low complexity adaptive stepsize approaches are investigated by exploiti...

Multiuser Orthogonal frequency division multiplexing (MU-OFDM) is one of the promising techniques for future cellular and wireless networks for achieving high downlink capacities. The objective of the next generation cellular and wireless networks, which are based on (MU-OFDM) is to increase the network efficiency by maximizing the total throughput of the system and minimizing the overall trans...

Orthogonal frequency division multiplexing (OFDM) is very sensitive to frequency errors caused by frequency differences between transmitter and receiver local oscillators. In this paper, this sensitivity is analyzed in terms of the complex weighting coefficients which give the contribution of each transmitter subcarrier to each demodulated subcarrier. Previously described windowing and self-int...

In this paper, we propose a subcarrier allocation method and a composite linear minimum mean square error (LMMSE) channel estimator to increase spectrum efficiency in orthogonal frequency division multiplexing (OFDM) transmit diversity. The pilot symbols for OFDM transmit (Alamouti) diversity are exclusively allocated in two OFDM symbols in different antennas, which causes serious degradation o...

The radio resource allocation in wireless communication is analysed in this paper. Pair of users communicates each other through multiple two way relays in orthogonal frequency division multiplexing transmission systems. The total throughput is maximized by relay selection, channel and relay assignment, subcarrier pairing and subcarrier allocation by prim’s algorithm. The graphical theory appro...

Optical spectral analysis of closely spaced, subcarrier multiplexed fiber-optic transmission is performed, based on stimulated Brillouin scattering (SBS). The Brillouin gain window of a single, continuous-wave pump is scanned across the spectral extent of the signal under test. The polarization pulling effect associated with SBS is employed to improve the rejection ratio of the analysis by an o...

This paper presents a fast low-complexity synchronization scheme for orthogonal frequency division multiplexing (OFDM) systems over fading channels. By utilizing the guard interval in OFDM signals, the frame synchronization and the frequency offset estimation are considered simultaneously. The implementation can be simplified by only using the sign bits of the in-phase and the quadrature compon...

Abstract— In a multiple input single output orthogonal frequency division multiplexing (MISO OFDM) system, per-subcarrier antenna selection is employed to improve the data rate over frequency selective fading channels. The antenna selection is based on the channel gain and the power balancing is achieved through allocating equal number of subcarriers to each antenna. This scheme of antenna sele...