The performance of a cooperative diversity with selection combining is analyzed in Rayleigh fading channels. The effect of limited power at the relay node is also presented. Our results show that when the average signal-to-noise ratio (SNR) of each branch is identical, the single relay cooperative diversity with selection combining provides 13.5 dB power gain over the non-cooperative system at ...

We propose combining channel estimation and optimal power allocation approaches for a multiple-antenna orthogonal frequency division multiplexing (OFDM) system in high-speed transmission applications. We develop a least-square channel estimation approach, derive the performance bound of the estimator, and investigate the optimal training sequences for initial channel acquisition. Based on the c...

Coherent beam combining enables power scaling beyond the limits of single amplifiers. Therefore, improving the performance and simplicity of coherent combination techniques is of great interest for many high power applications. Here, we show all-fiber coherent beam combining of two ytterbium doped amplifiers with and without a dedicated phase actuator and a total output power up to 25 W. Instea...

We present multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) based broadband power line communication (BPLC) using antenna and fading diversity. We evaluate the proposed MIMO-OFDM system over multi-conductor power line channels, with or without cross-talk between the antenna paths. The proposed scheme employs maximum ratio combining (MRC) that effectively com...

a filtering power divider/power combiner based on half mode substrate integrated waveguide technology for high power applications is proposed. this design includes one half mode substrate integrated waveguide cavity, one matched load, and four sections of quarter-wavelength transmission lines. the high isolation between output ports is obtained by combining the half mode substrate integrated wa...

Radio communication systems of the future will require a large increase in user capacity. To achieve this, cell sizes will reduce and the number of base stations will increase. Current base station architectures use analogue combining techniques which are expensive, voluminous and inflexible. This thesis investigates a Digital Signal Processing (DSP) solution which produces a cheaper, smaller a...

Voltage sag/swell is one of the most frequently power quality problems which affects the power systems with sensitive loads. The unified power quality conditioner (UPQC) is capable of mitigating the effect of voltage sag/swell at the load or point of common coupling (PCC). In this paper, a new control of UPQC is proposed based on combining the sag detection and voltage injection established on ...