Sharif Digital Repository

The long term evolution (LTE) standard is introduced and developed by the 3rd generation partnership project (3GPP) based on orthogonal frequency division multiplexing (OFDM). OFDM systems, in spite of having many advantages such high performance in bandwidth usage, are very sensitive to inter carrier interference (ICI) as a drawback. In order to prevent ICI, the frequency offset, mainly caused by the miss-match between oscillators' frequency and also between the sampling frequency of the transmitter and the receiver, should be estimated and compensated. Frequency synchronization is a part of the tasks of a synchronizer. In this thesis, main tasks of a synchronizer are illustrated and... 

In this thesis, a hardware is designed and implemented for testing the perfoemance of MIMO communication systems in LTE standard using SCM channel model. This hardware can be used for measuring the BER of 2x2 wireless systems. This hardware is the first channel emulator, with hardware implementation which is using SCM channel model and implementation of a similar one has not been reported.In addition to the implementation of the mentioned channel emulator, a new approach is used for implementing a Gaussian variate generator (GVG) which is implemented on both FPGA and ASIC and shows better characteristics in comparison with the works done in the past. ASIC implementation of this part is done... 

Long Term Evolution (LTE), is a standard for wireless communication of high-speed data for mobile phones and data terminals. Increasing the capacity, improved support for mobility and simplified architecture are a number of its goals. As many other standardas LTE uses Multiple Input-Multiple Output (MIMO), which is a system that uses multple antennas in the transmitter and the reciver. LTE has adopted single carrieer-frequency division multiple access (SC-FDMA) for the uplink multiple access scheme in order to decrease peak to average power ratio (PAPR). In SC-FDMA a discrete Fourier transform (DFT) is performed on the signlas before going through the OFDMA modulation.
A novel... 

Frequency scarcity has emerged the necessity of opportunistic utilization of frequency bands, which can be realized through a cognitive radio system. During an agile communication between unlicensed users, a cognitive radio system must avoid collision with licensed users. Hence it should continuously observe the band of interest and report the presence of licensed user signals. This task is fulfilled by a vital part of a cognitive radio system, called the spectrum sensing core. Recently several techniques have been proposed for the spectrum sensing in literature. Some of them like matched filtering, cyclostationarity based detection are based on primary user signal features. However energy... 

The rapid growth in the health care technology, has made the Body Area Network (BAN) as an attracting topic for research and design development. BAN devices have restrictions on their size and power consumption. Monitoring the respiratory signal is crucial in many medical applications and is normally part of a BAN system. Traditional methods for the respiration measurement are normally based on measuring the volume of air inhaled and exhaled by lungs (like a spirometer) or oxygen saturation in blood. However, these methods have numerous drawbacks including their high cost and limited accessibility. In this thesis, a novel scheme is proposed to derive the respiratory signal from the... 

Coding information data is one of the ways to prevent noise effect on the information bits, during passing communication channels. Coding data gives the possibility to detect and correct the data in the receiver. The LDPC codes which were first introduced by Gallager in the 1962 are forward error correction codes and can approach the Shannon’s capacity to within hundredths of a decibel.
In this project a modified algorithm for decoding these group of codes is introduced, which can achieve acceptable bit error rate, while it can have better throughput than the same implementations. This algorithm is implemented partial-parallel for IEEE802.11n standard in ASIC. It is shown that, it has... 

After being introduced in 2009, the first fully homomorphic encryption (FHE) scheme has created significant excitement in academia and industry. Despite rapid advances in the last 6 years, FHE schemes are still not ready for deployment due to an efficiency bottleneck. Here we introduce a hardware/software codesign, in fact a hardware accelerator optimized for a class of reconfigurable logic to bring homomorphic encryption schemes one step closer to deployment in real-life applications. The accelerator we present is connected via a fast PCIe interface to a CPU platform to provide homomorphic evaluation services to any application that needs to support blinde computations. Specifically we... 

This thesis addresses cuff-less blood pressure (BP) estimation, for systolic blood pressure (SBP) and diastolic blood pressure (DBP) estimation with the aid of the processing of vital signals. Both with and without calibration per person approaches for BP estimation are considered. A data acquisition hardware is designed for high-resolution sampling of phonocardiogram (PCG), Photoplethysmogram (PPG) and electrocardiogram (ECG). Using these signals, pulse transit time (PTT) and pulse arrival time (PAT) indexes, which would be used for BP estimation with calibration, are extracted. For the BP estimator model using the calibration, A nonlinear model based on PTT or PAT, via modeling the vessels... 

Massive-MIMO and C-RAN are the two technologies which will be among most important parts of fifth generation (5G) stsrems. They will find widespread uses in future years. However, data transfer rate between these two technologies is a challenging problem. Also channel estimation is crucial in massive-MIMO systems. In this research, the problem of estimating the channel and the problems with the data transfer rate between these two technologies are investigated. We propose using 1-bit quantizers to solve the rate problem and also an algorithm with perfect performance in aspect of error rate is proposed. The mentioned algorithm is implemented on GPUs, which are available at C-RANs and resulted... 

Long Term Evolution (LTE) aims the peak data rates in excess of 300 Mb/s, which may appear to be challenging to achieve due to the existence of some blocks such as the turbo decoder. One efficient approach to achieve this throughput is by parallelizing the Log Maximum a Posteriori (MAP) algorithm in the turbo decoder. In fact, the interleaver is known to be a major challenging part of the turbo decoder due to its need to the parallel interleaved memory access. LTE uses Quadratic Permutation Polynomial (QPP) interleaver, which makes it suitable for the parallel decoding. In this thesis, first, we propose an efficient architecture for the QPP interleaver, called the Add-Compare-Select (ACS)... 

Massive MIMO is a key enabling technology in the fifth generation (5G) wireless communication systems. In this technology, the base station is equipped with a large number of antennas (e.g. 100-200) and communicates with a relatively smaller number of user terminals. The large number of antennas at the base station, on one hand, has enabled unprecedented improvements in data rate and energy-efficiency, while on the other hand has posed challenges on the practical deployment of this technology.One of these challenges, is the high computational complexity of the baseband processing algorithms, such as precoding, due to the large number of antennas. In this research, we propose a novel ZF... 

Today, telecommunication links transmit information wirelessly at high rates; The transmission channel is not ideal and the transmitted signal undergoes changes in the channel and then reaches the receiver; Also, the processing blocks in the transmitter and receiver are not completely similar and ideal; These two factors make it difficult for the receiver to recover the transmitted information and actually receives a signal that bears little resemblance to the transmitted signal. The most important effect that the channel has on the transmitted signal is due to the multi-path of the channel between the transmitter and the receiver, which causes a signal to reach the receiver through the... 

Make a connection between brain and computer, or Brain Computer Interface (BCI) for broad applications in areas such as medical and gamming has caused the subject to one of the most important and attractive issues in recent decades. From the perspective of pattern recognition, BCI is a classification issue that should receive signals that relate to the certain decisions of the brain and then after processing, it is concluded that the person has thought to what decision. Decisions that taken by individual, is sent from the brain to the body by signals, which is called Electroencephalogram (EEG). The number of these decisions is further, classified it also becomes more difficult. That is why... 

Continuous Blood Pressure monitoring can provide invaluable information about individuals’ health conditions. However, BP is conventionally measured using inconvenient cuff-based instruments, which prevents continuous BP monitoring. This work presents an efficient algorithm, based on the Pulse Arrival Time (PAT), for the continuous and cuff-less estimation of the Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Mean Arterial Pressure (MAP) values. The proposed framework estimates the BP values through processing vital signals and extracting two types of features, which are based on either physiological parameters or whole-based representation of vital signals. Finally, the... 

Hypertension precvalence is 24 and 20.5 percent in men and women, respectively. Continuous Blood Pressure monitoring can provide invaluable information about individuals’ health conditions. However, BP is conventionally measured using inconvenient cuff-based instruments, which prevents continuous BP monitoring. This work presents an efficient algorithm, based on the Pulse Arrival Time (PAT), extracted from Electrocardiogram (ECG) and Photopletysmograph (PPG), for the continuous and cuff-less estimation of the Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Mean Arterial Pressure (MAP) values. Methods: The proposed framework estimates the BP values through processing vital... 

Ever increasing demand for higher data rate in wireless communication in the face of limited or underutilized spectral resources has motivated the introduction of cognitive radio for dynamic access to spectrum. In dynamic spectrum access a new type of users called secondary users measure the spectrum to see if it is occupied by licensed users (primary users or PU). When channel is empty secondary users can use it to transmit signal. This approach is called spectrum sensing. Hidden PU problem can severely defect detection ability of non-cooperativ spectrum sensing systems. Cooperative spectrum sensing (CSS) uses spatial diversity of spectrum sensors to tackle this problem. There are two kinds... 

Optical Communication is a promising technology in access networks because of bandwidth hungry application like videos. So fiber Optic is an important candidate as a media in networks. There are different methods of modulation for transferring data through a channel. Among all, Orthogonal Frequency Division Multiplexing is a method which used in most wired and wireless systems. Recent researches show that OFDM is also a good approach for optical communication.
In this thesis we concentrate on hardware implementation of digital part of an Optical OFDM transceiver. In the first step we ignore the effect of optical channel and design and simulate the transmitter and receiver. After that we... 

Spiking neural networks (SNNs) are third generation of neural networks. Similar to traditional neural networks, SNNs are comprised neurons. However, not only structure but also information processing is inspired by animal neural systems. SNNs can be called the most similar networks to animal neural systems. In such networks, the information is processed based on propagation of spike signals through the network. The type of data flow in these networks leads to being low-power when they are implemented on hardware. Therefore,there has been a upward trend in hardware implementation of them, like their FPGA implementations, for applications such as Big Data and Machine Learning. In this thesis,... 

Positioning refers to the process of estimating the receiver coordinates aiming for an accurate understanding of the surrounding environment. This branch of science has attracted considerable attention in recent years. Today, the influence sphere of positioning is so expanded that encompasses applications in daily life (e.g., navigation) as well as commercial and even military fields. Global Positioning System (GPS) is the most widely used tool in real-time positioning. Because GPS imposes great measurement errors in challenging conditions (e.g., turbulent water environments), alternative methods such as methods based on Wi-Fi, Bluetooth, and visible light have been proposed. Benefiting... 

The application of deep learning algorithms in the processing of telecommunication signals is increasing. One of the issues in this area is the automatic recognition of radio signal modulation. Recognizing the type of signal modulation as the first stage of baseband signal processing on the receiver side is a key issue in military and civilian applications. The problem with classical algorithms for solving this problem is their strong dependence on channel characteristics and factors resulting from the transmitter and receiver being non-ideal. However, modern algorithms based on deep neural networks have been able to make the model somewhat resistant to these factors. However, the detection...