Large-scale (LS) multi-user (MU) multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) is considered to be a desirable signal transmission scheme because it can significantly improve the energy efficiency (EE) and spectral efficiency (SE) of the system. However, there are many difficulties in realizing an LS-MU-MIMO-OFDM system, and one of these is its high peak-...

In this paper, we propose a low complexity clipping method to reduce the peak power of OFDM signals. The proposed clipping method exploits the conventional square clipping, which clips signal according to the amplitude in I/Q-channels separately, to avoid obtaining a real amplitude of each sample which costs relatively high computational complexities. By combining the square clipping and phase ...

 Poor accuracy of frequency references used in GSM Base Transceiver Stations (BTS) can lead to dropped calls, slow handover between cells and even co-channel interference. In this paper, we report some results of an experimental trial carried out in the Omnitel-Vodafone test plant in Milano (Italy). In authors' knowledge, this is the first paper confirming with experimental data that lack of B...

Masking at the Interaction Region (IR) will presumably reduce the synchrotron radiation background in the detector. One possible layout of the IR for the B factory, depicted in Fig. 1, shows a rather complicated system of masks. A bunch passing each mask will generate RF waves. These waves (usually called higher order modes, HOMs) will be absorbed in the beam pipe wall producing additional heat...

For bunches stretched with a higher-harmonic cavity, longitudinal bunch shapes are influenced by small variations in the potential wells of the buckets of the bunch train. This paper discusses three things that perturb the bunch shapes in the NSLS VUV ring: the 90 (non-optimal) phase of the harmonic cavity maintained by the RF controls [1], higher-order modes (HOM) of the main cavity, and the e...

The paper presents Space-Frequency Block Coding (SFBC) as a transmit diversity technique in Single Carrier Frequency Division Multiple Access (SC-FDMA). SC-FDMA is known as a low Peak-to-Average Power Ratio (PAPR) modulation technique. SFBC requires changing the order of the samples in the frequency domain, which results in increase of the PAPR. Because of that, additional clipping and filterin...

This paper presents a new engineering approach to audio clipping preamplifier that can be used for the tone modification and volume control of electronic devices. The approach consists of a unique design based on a summation amplifier, Silicon Controlled Rectifiers (SCR) and RC networks that enables signal gain, improved frequency response, tone modification and signal shape clipping. The propo...