In this paper, a new scheme for serial communication is proposed. In this method, in addition to the pulse states (high and low), either of negative slope or positive slope of the pulse (saw-tooth waveform) is employed as a representative for another digit. Using pulse slope as a representative for a separate digit will result in sending two-bit-digits using a single pulse, which doubles the transfer rate. The proposed scheme can be used in both synchronized and asynchronized communications and can improve communication speed. Through simulating the proposed scheme, it turned out that this method, because of its proper immunity to noise, can be used as a peripheral interface alongside in-chip communication. The main idea in the raised discussion is to obtain four different geometric pulse shapes acting as four different numbers in the quaternary numeric system, in which it can be serialized/desrialized as easy as pulse states. This proposed method and the suggested system for serialization and deserialization of data can be an adequate alternative in high-speed communication approaches.

In this article, we designed a novel monolithic integrated optical Transceiver based on the ring resonator structure on semi-insulating In P substrate at 1.55 mm wavelength. To separate the incoming continuous (l2) and modulated (l1) optical waves from the network, an optical ring resonator is utilized. The ring resonator has the p-i-n layer stack that also detects the incoming modulated optical wave (l1). The continuous optical wave (l2) is guided to the ring-resonator based modulator where it is modulated and finally directed toward a pair of ring resonator to reflected back to the network. Channel spacing between l1 and l2 is 200 GHz (1.6 nm) at wavelength ranges of 1520 to 1570 nm. This Transceiver can illustrate a 40 GHz bandwidth.

This paper studies interference alignment scheme and minimum mean square error (MMSE) improvement in Internet of Things (IoT)-oriented cognitive systems, where IoT devices share the licensed spectrum by cognitive radio in spectrum underlay. Target to manage the intertier interference caused by cognitive spectrum sharing as well as ensure an MMSE at receivers, the interference alignment algorithms is proposed. In particular, we focus on the problem of designing the optimal linear pre-coding to minimize the total mean square error while satisfying transmit power constraints. Firstly, we introduce a system model of the downlink IoT-oriented cognitive multi-input multi-output (MIMO) system. Secondly, we propose an interference nulling based cognitive interference alignment scheme, and then, the pre-coding and post-coding matrix designs for the primary Transceivers to minimum mean square error (MSE), as well as to eliminate the cochannel interference to the primary receivers. We also apply these interference alignment scheme and matrix designs for the secondary links. Finally, the numerical results are used to evaluate performance of the proposed algorithm.

The use of array antennas in mobile telecommunication systems has proven to increase the spectrum efficiency of the system. The use of beamforming techniques poses high linearity demands on both the RF/IF up and down conversion chain. In this paper, an overview of the various nonlinear effects is first presented. By the way amplitude distortion produced in the transmitter up conversion chain and amplification that can affect the antenna beam specification is simulated. Results show that the IMD products increase the level of spurious radiation and ultimately reduce the performance of the beamformer. In the receiving mode, AM-AM conversion due to gain compression of the Low Noise Amplifiers (LNAs) is modeled and the beam pattern degradation is simulated. Using behavioral modeling, a new relation for AM-PM conversion is established as a gain compression. Results show that the amplitude and phase distortion of the LNA vary for different gain setting and over signal bandwidth and indicate the need for regular calibration in using beamforming techniques. Also, results show that the produced radiation pattern is more affected by AM-PM distortion rather than AM-AM distortion.

This study presents modeling and simulation of a stand-alone hybrid energy system for a base Transceiverstation (BTS). The system is consisted of a wind and turbine photovoltaic (PV) panels as renewableresources, and also batteries to store excess energy in order to boost the system reliability. Two differenttypes of batteries are considered for storage purposes; lead-acid and vanadium redox-flow batteries (VRB)batteries. Most stand-alone energy systems for various applications take advantage of at least a singlestorage technology, generally lead-acid batteries. However, with recent advances in different batterytechnologies, vanadium redox-flow batteries could be taken into account as reliable candidate. Thevanadium redox-flow battery has a desirable prospect due to its extended life span and also the potentialfor separating and scaling up involved nominal power and nominal energy. The system is modelled andsimulated hourly (quasi-dynamically) in Matlab for an operational year. The model utilizes insolation,wind speed and air temperature data. The system performance has been assessed with a mobile telephoneBase Transceiver Stations (BTS) as the case study. Simulations results have shown that the suggestedmodel can be used to study the effect of the altering weather conditions on each charge/discharge cyclesand batteries voltage. Finally the proposed model yields the optimal battery network design for a varietyof applications.

This paper addresses a novel Alamouti space-frequency block decoding scheme with discontinuous Doppler diversity (DDoD) and cyclic delay diversity (CDD). We investigate different antenna diversity concepts, which can be applied to orthogonal frequency division multiplexing (OFDM) systems over highly frequency selective channels. The main object of this research is standard compatibility and the effect of simple diversity techniques on the channel fading properties. Therefore, we analyze a receiver in terms of the effective channel transfer function, which leads to the possibility of optimizing diversity. Besides, a novel Transceiver using DDoD is proposed, which increases the Doppler spread of the multipath fading channel without causing additional Intercarrier Interference (ICI). Moreover, an efficient Alamouti encoder and decoder based on CDD is proposed, which allows a high reliability and capacity enhancement. In order to evaluate the capability of that, we have implemented this scheme for the second-generation terrestrial video broadcasting (DVB-T2) system over different channels. Furthermore, mathematical analysis and simulation results show the bit error performance of the modified encoding method with these diversity techniques, performs mostly better than the other forms of encoding Alamouti over highly frequency-selective channels such as single frequency networks (SFN). The other advantages of the proposed method are simplicity, flexibility, and standard compatibility.

SPDT switches are used as duplexer in wireless systems, as WIMAX, to switch between transmit and receive states. Microwave SPDT switches may be designed using FET’s or PIN diodes. However, PIN diode is suitable for duplexer applications due to its high power handling capability. I general, in frequencies higher than 3 GHz, isolation better than 30 dB is a challenge. This is due to the parasitic inductance of PIN diode. In this paper, we propose a new structure for SDPT PIN diode switch to overcome this challenge. In the proposed structure a micro-strip line is adopted parallel to the diode. This line, in conjunction with another micro-strip line that is in series with the diode, eliminates the diode inductance in on-state and the diode capacitance in off-state, and hence improves both of isolation and insertion loss. The proposed structure has been analyzed mathematically and analytic equations have been derived to design the proposed switch. Finally, simulation results have been used to validate the performance of the switch. Simulations are performed using SMP1340 PIN diode and the model presented by the diode manufacturer. The simulations are in ADS and EM and EM_Cosim simulators are used to simulate the switch layout and include the layout effects accurately. Simulation results show more than 50dB isolation and less than 0.2dB insertion loss.