نشریه مهندسی مخابرات جنوب
پیاپی 38 (زمستان 1399)

Current 4G networks were not designed for small cells promiscuous. Based on long-term evolution of the transmission time interval of about 5 milliseconds is a cyclic prefix milliseconds and this has caused. Also, a small cell base station (LTE) eNB is highly similar to a large cell eNB mature in functional areas, with the ability to move less. In addition, the interface cell is controlled to a large amount planned by arrangement With the rapid development of wireless technologies, the concept was introduced the fifth-generation communication systems; that with the progress of each telecom subscribers can connect to the Internet at a speed of 11 thousand Gbps. This makes the system very intelligent routing and data transfer with high speed and security. It is the process of separating hardware from software and the networking functions than a second. Software Defined Networking Foundation Network SDN by the standard theory of separation of control and data becomes smoother. As a result, thanks to the focus and planning, maintenance is largely automated. In this context, a system that is used to implement it, the nodes that are pasted packets are quite smart and intelligent algorithm based on the route and the destination node. This makes the system very intelligent routing and data transfer with high speed and security. In this article, we have tried to measure the QoS parameters in WiMAX networks and network performance 5G to compare them and examine the data transfer.

Short-term load forecasting is very important in electrical marketing. Load forecasting is dependent on climatic condition of every region and the previous structures of electrical consumption in that region; so we have accomplished this through employing climatic data (including temperature and pressure) and real load consumption of Chaharmahal Bakhtiari. We have evaluated our method using four machine learning algorithms: artificial neural networks (multilayer perceptron), ensemble of artificial neural networks, support vector machine and ensemble of support vector machine. Experimental results indicates that ensemble of artificial neural networks is superior to the others in the field of load consumption forecasting of Chaharmahal Bakhtiari.

In this article, a high-speed analog-to-digital column-parallel converter with a small 12-bit resolution on both sides of the image sensor is proposed. This article also proposes a comparator with low offset. A method for accelerating the conversion speed using synchronization of variables (variable clock) and sampling capacitors have been developed. The pixel load amplifier achieves a light sensitivity of 9.19 V/lxs. The full signal size at the pixel output is 1/8V at the 3/3V power supply and the noise level is 1.8 and the dynamic signal amplitude is 60db. Finally, this circuit was simulated with HSPICE software and acceptable results were obtained. This circuit requires a voltage of 3.3V and is 0.35um in technology. Power consumption is 11 mW and SFDR is equivalent to 66dB, THD is equivalent to -2 and SNDR is equivalent to 40dB.

Analog multipliers are useful blocks used in implementing functions such as automatic control, modulation, detectors, adaptive filters, and neural networks. In this paper, we present a new four-quadratic analog multiplier based on carbon nanotube transistors. Newly designed current square circuits and a current mirror, all operating at low voltage (1V), are essential components in realizing mathematical equations. The multiplier circuit is designed using CNTFET technology, 32 nm, and the multiplier provided in the HSPICE simulator is simulated to validate the circuit performance. The simulation results showed that the circuit has the desired performance up to a frequency of 2 GHz and shows a maximum power consumption of 3.7464uw and also has a THD of 0.226043%.

In recent years, the need for reliable transmission of digital data is increasing rapidly And extend high-speed data networks and wireless networks in public and private business were caused It would be considered.With OFDM multi-carrier modulation and consists of several sub-carrier is modulated have to be perpendicular to each other. The disadvantages of multi-carrier modulation, such as OFDM, greater than Peak-to-Average Power Ratio PAPR at the transmitter output signal is PAPR large signal, causes the amplifier with a wider range of linear functions necessary. That is effective and if the amplifier can be used with low linear operation area, causing distortion in band and out of band signal will be sent radiation. In this paper, both Precoding techniques and Companding μ-law used to reduce PAPR Further studies using different methods and number of sub-carrier modulation is different. A significant decrease in the values of PAPP using these techniques have been. And efficacy compared with each other.

To classify text information extraction techniques, natural language processing and machine learning has been widely used general purpose of categories of documents, classified documents in the form of a certain number of categories are pre-determined. Each document can be in one, several or no category is placed. In the case of any document to this question will be placed the document on which of the categories. This can be in the form of an automatic learning to use it any document can be automatically assigned to a category.     In this thesis, data collection and cleanup after you select text using the normal method of word frequency -inverse document frequency (norm TF-IDF) is the weight features and features in two stages using document frequency (DF) and Chi square (SChi) are selected, and then using principal component analysis (PCA) features reduced dimensions, and at a later stage by combining 21 support vector machine (SVM) the proposed model we have implemented, and the accuracy of the model to assess the 10-step method validation. Experimental results show that this model can text classification accuracy of 91.86 for the seven categories do, which has a higher accuracy than the earlier work done.