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Vehicular Ad-Hoc Network (VANET) is the fundamental part of future Intelligent Transportation System (ITS). Physical layer is applied to provide messages transmission between vehicle nodes in VANET, so it has great influence on efficiency of ITS. On the basis of analyzing IEEE 802.11p protocol, we presented a design scheme for physical layer communication system of On Board Unit (OBU) in VANET. Furthermore,...
This paper firstly introduces the principles of SPWM (space vector pulse width modulation) and SVPWM (sinusoidal pulse width modulation), and then builds PMSM (permanent magnet synchronous motor) control system simulation models based on SPWM and SVPWM in MATLAB/Simulink environment. Finally, by comparing the simulation results of the two models, we got the advantages and disadvantages of SPWM and...
This paper presents techniques for increasing communication data rates for OOK modulated signals in the case the carrier frequency is generated by a cross-coupled pair LC oscillator. The proposed circuitry completely turns off the transmitter during the transmission of “0” bit and oscillation occurs only when the data bit is “1” to reduce power consumption. The data bit controls the steady state bias...
Neighbor discovery is a crucial initial step to establish connections among the nodes in Ad hoc network. Multi-carrier modulation possesses superiority on parallel processing, which is widely used in neighbor discovery researches with directional antennas. However, when the node scale becomes larger, the existing algorithms of 1-way and 2-way handshake may increase the collision probability, leading...
In this work we implement features for IEEE 802.11ac in the NS-3 simulator, in particular wider channels and bit-error calculations for higher modulation coding schemes. We also implement four wireless LAN deployment scenarios from the 802.11ax working group scenario document, and evaluate their performance under different operating conditions. Our simulation results demonstrate that many nodes in...
This paper presents an analysis of the operation of cascaded H-Bridge Converter with bypassed cells during fault conditions. Several new properties of the converter are derived for maximizing the output line voltages of the converter. It is achieved by adjusting the phase angles of the three reference signals given to individual legs of the converter. Analytical expressions for the phase angle is...
Active neutral-point-clamped (ANPC) converter is a well-known type of multilevel converter which is commercially available in high-power medium-voltage drive market. Since conduction loss investigation is advantageous in design phase of converters, this paper presents an analytical approach to calculate and investigate conduction power loss in ANPC converter. First, rms and average currents of IGBTs...
Multilevel converters are attractive solution for high-power high-voltage applications such as motor drive systems, active filters, and flexible AC transmission systems (FACTS). Several modulation techniques are proposed for multilevel converters. Among them, selective harmonic elimination (SHE) offers high quality voltage waveform with low switching frequency which is especially suitable for high-power...
In this paper, the effect of Doppler spread in Subcarrier Index Modulation-OFDM (SIM-OFDM), one of the multicarrier transmission systems, is compared to OFDM system that the most widely used multi-carrier transmission method. For this purpose, average subcarriers interval was derived from SIM-OFDM. The results showed the performance improvement by calculating Signal-to-Interference Ratio (SIR) and...
High Peak-to-Average Power Ratio (PAPR) is one of the main drawbacks that may limit practical applications of Orthogonal Frequency Division Multiplexing (OFDM) System. Based on the well known Selective Mapping (SLM) method of PAPR reduction, in this paper, we propose a new phase sequence generation technique from Condex matrix that can achieve better PAPR reduction compared to the generally used Bauml...
To cope with power from large-scale renewable systems, more and more power electronic converters are used in parallel. Typically, carrier interleaving is used, thus leading to a decrease in filtering requirements. However, this causes additional circulating current to flow between the modules of the converter. The modules of the parallel converters are Voltage Source Converters (VSC). Usually, a coupled...
Fault tolerant ability is one of the most important tasks in high power converters. In this paper, a comparison between conventional fault tolerant methods is done for four applicable methods. For this purpose, their performance is investigated in specific case study and simulation results are used to illustrate their advantages and disadvantages. The most important features taken into account are...
In this paper an induction motor drive system based on a fault-tolerant cascaded H-bridge converter is presented. The proposed system is composed by an induction motor fed through a 13-level cascaded H-bridge converter. In this case a neutral shift method has been implemented for the CHB converter in order to make it fault-tolerant. The proposed system has been modelled and tested in Matlab-Simulink.
This paper presents the design of an average controller based on differential flatness for a DC/DC Boost power converter. This controller allows the system output voltage to perform the trajectory tracking task. When designing control laws based on the average model of switched systems a modulator is necessary to appropriately govern the converter switch. Thus, the switched implementation of the designed...
In this work, constellation constrained (CC) capacities of a series of non-orthogonal overloading transmission schemes are derived in AWGN channels. All these schemes follow a similar transmission structure, in which modulated symbols are spread on to a group of resource elements (REs) in a sparse manner, i.e., only a part of the REs have nonzero components while the others are filled with zeros....
This paper proposes a new design and implementation of a single stage three-phase multi-level inverter (MLI). The suggested inverter is modular type and can be generalized by connecting the basic modular cells in series configuration. In addition, it can be operated with symmetrical/asymmetrical Dc-voltage sources. The proposed MLI is successfully modulated using sinusoidal pulse width modulation...
Sphere Decoding (SD) algorithm was proposed to effectively find the Maximum Likelihood (ML) solution. However, the computational complexity of SD is still too high when SNR is low or the dimension of the problem is large. In this paper, we propose three improved schemes based on contraction factor to reduce the complexity of sphere decoding. In the proposed schemes, a factor was introduced for speeding...
Bit-interleaved coded modulation with iterative decoding (BICM-ID) are suitable for continuous fading channels. In addition, BICM-ID using differential encoding can avoid the rate loss due to pilot symbols. Conventional differential encoding for uncoded modulation was used for BICM-ID. In this paper, we propose new differential encoding of 16APSK (amplitude and phase-shift keying) signals for BICM-ID...
MMCs are normally designed to operate in the linear region of the PWM. This limits the peak-to-peak phase voltage in the AC port to be lower than the DC port voltage. It is possible to increase the AC voltage beyond this limit by the use of overmodulation strategies. However, this is at the price of an increase in the harmonic content (THD) of the voltages and currents, and consequently, of a decrease...
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