List of Articles Interference

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  1 - An Improved Method for TOA Estimation in TH-UWB System considering Multipath Effects and Interference
  Mahdieh Ghasemlou Saeid Nader Esfahani Vahid  Tabataba Vakili
  10.7508/jist.2014.01.003
  UWB ranging is usually based on the time-of-arrival (TOA) estimation of the first path. There are two major challenges in TOA estimation. One challenge is to deal with multipath channel, especially in indoor environments. The other challenge is the existence of interfer More

  UWB ranging is usually based on the time-of-arrival (TOA) estimation of the first path. There are two major challenges in TOA estimation. One challenge is to deal with multipath channel, especially in indoor environments. The other challenge is the existence of interference from other sources. In this paper, we propose a new method of TOA estimation, which is very robust against the interference. In this method, during the phase of TOA estimation, the transmitter sends its pulses in random positions within the frame. This makes the position of the interference relative to the main pulse to be random. Consequently, the energy of interference would be distributed, almost uniformly, along the frame. In energy detection methodes, a constant interference along the frame does not affect the detection of arrival time and only needs the adjustment of the threshold. Simulation results in IEEE.802.15.4a channels show that, even in presence of very strong interference, TOA estimation error of less than 3 nanoseconds is feasible with the proposed method. Manuscript profile
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  2 - PSO-Algorithm-Assisted Multiuser Detection for Multiuser and Inter-symbol Interference Suppression in CDMA Communications
  Atefeh Haji Jamali Arani paeez azmi
  10.7508/jist.2014.01.006
  Applying particle swarm optimization (PSO) algorithm has become a widespread heuristic technique in many fields of engineering. In this paper, we apply PSO algorithm in additive white Gaussian noise (AWGN) and multipath fading channels. In the proposed method, PSO algor More

  Applying particle swarm optimization (PSO) algorithm has become a widespread heuristic technique in many fields of engineering. In this paper, we apply PSO algorithm in additive white Gaussian noise (AWGN) and multipath fading channels. In the proposed method, PSO algorithm was applied to solve joint multiuser and inter-symbol interference (ISI) suppression problems in the code-division multiple-access (CDMA) systems over multipath Rayleigh fading channel and consequently, to reduce the computational complexity. At the first stage, to initialize the POS algorithm, conventional detector (CD) was employed. Then, time-varying acceleration coefficients (TVAC) were used in the PSO algorithm. The simulation results indicated that the performance of PSO-based multiuser detection (MUD) with TVAC is promising and it is outperforming the CD. Manuscript profile
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  3 - A Linear Model for Energy-Aware Scheduling Problem Considering Interference in Real-time Wireless Sensor Networks
  Maryam  Hamidanvar rafeh rafeh
  10.7508/jist.2015.04.007
  An important factor in increasing quality of service in real-time wireless networks is minimizing energy consumption, which contradicts with increasing message delivery rate because of associating a time deadline to each message. In these networks, every message has a t More

  An important factor in increasing quality of service in real-time wireless networks is minimizing energy consumption, which contradicts with increasing message delivery rate because of associating a time deadline to each message. In these networks, every message has a time deadline constraint and when the message is not delivered to its destination before its deadline constraint, it will drop. Therefore, scheduling methods that simultaneously consider both energy consumption and time deadline constraint are needed. An effective method for reducing energy consumption is multi-hop transmission of packets. However, this method takes longer time for transmission as compared to single-hop transmission. Parallel transmission is another approach which on one hand reduces the transmission time and on the other hand increases the network throughput. However, a main issue with parallel transmission is the presence of interference among nearby nodes. In this paper, we propose a linear model (ILP formulation) for energy aware scheduling problem in real-time wireless sensor networks using parallel transmission. The main objective of the model is to reduce energy consumption and packet loss using multi-hop routing and parallel transmission. Experimental results show that the proposed model finds the optimum solution for the problem and outperforms the sequential scheduling based on the TDMA protocol. Manuscript profile
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  4 - A New Capacity Theorem for the Gaussian Channel with Two-sided Input and Noise Dependent State Information
  Nima S. Anzabi-Nezhad Ghosheh  Abed Hodtani
  10.7508/jist.2019.04.005
  Gaussian interference known at the transmitter can be fully canceled in a Gaussian communication channel employing dirty paper coding, as Costa shows, when interference is independent of the channel noise and when the channel input designed independently of the interfer More

  Gaussian interference known at the transmitter can be fully canceled in a Gaussian communication channel employing dirty paper coding, as Costa shows, when interference is independent of the channel noise and when the channel input designed independently of the interference. In this paper, a new and general version of the Gaussian channel in presence of two-sided state information correlated to the channel input and noise is considered. Determining a general achievable rate for the channel and obtaining the capacity in a non-limiting case, we try to analyze and solve the Gaussian version of the Cover-Chiang theorem mathematically and information-theoretically. Our capacity theorem, while including all previous theorems as its special cases, explains situations that can not be analyzed by them; for example, the effect of the correlation between the side information and the channel input on the capacity of the channel that can not be analyzed with Costa’s “writing on dirty paper" theorem. Meanwhile, we try to exemplify the concept of “cognition" of the transmitter or the receiver on a variable (here, the channel noise) with the information-theoretic concept of “side information" correlated to that variable and known at the transmitter or at the receiver. According to our theorem, the channel capacity is an increasing function of the mutual information of the side information and the channel noise. Manuscript profile
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  5 - Implementation of Uplink and Downlink Non-Orthogonal Multiple Access (NOMA) on Zync FPGA Device
  Ahmed Belhani Hichem Semira Rania Kheddara Ghada Hassis
  10.61186/jist.33595.11.44.269
  The non-orthogonal access schemes are one of the multiple access techniques that are candidates to become an access technique for the next generation access radio. Power-domain non-orthogonal multiple-access (NOMA) is among these promising technologies. Improving the ne More

  The non-orthogonal access schemes are one of the multiple access techniques that are candidates to become an access technique for the next generation access radio. Power-domain non-orthogonal multiple-access (NOMA) is among these promising technologies. Improving the network capacity by providing massive connectivity through sharing the same spectral resources is the main advantage that this technique offers. The NOMA technique consists of exploiting the power domain which multiplex multiple users on the same resources applying a superposition coding then separating the multiplexed users at the receiver side. Due to the non-orthogonality access technique, the main disadvantage of NOMA is the presence of interferences between users. That is why this scheme is based on a successive interference cancelation (SIC) detector that separates the multiplexed signals at the receiver. In this paper, an embedded system is considered for designing and implementation of the power-NOMA For two users. The implementation is realized by employing a Zynq FPGA (Field programmable gate array) device through the Zybo-Z7 board using MATLAB/Simulink environment and Xilinx System Generator. The features offered by this device, hemps to consider the design of an uplink and a downlink scenario over Rayleigh fading channel in additive white Gaussian noise (AWGN) environment. Manuscript profile
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  6 - An Analysis of the Signal-to-Interference Ratio in UAV-based Telecommunication Networks
  hamid jafaripour Mohammad Fathi
  10.61186/jist.40342.12.45.49
  One of the most important issues in wireless telecommunication systems is to study coverage efficiency in urban environments. Coverage efficiency means improving the signal-to-interference ratio (SIR) by providing a maximum telecommunication coverage and establishing hi More

  One of the most important issues in wireless telecommunication systems is to study coverage efficiency in urban environments. Coverage efficiency means improving the signal-to-interference ratio (SIR) by providing a maximum telecommunication coverage and establishing high-quality communication for users. In this paper, we use unmanned aerial vehicle (UAVs) as air base stations (BS) to investigate and improve the issue of maximizing coverage with minimal interference. First, we calculate the optimal height of the UAVs for the coverage radius of 400, 450, 500, 550, and 600 meters. Then, using simulation, we calculate and examine the value and status of SIR in UAVs with omnidirectional and directional antenna modes in symmetric and asymmetric altitude conditions, with and without considering the height of the UAVs. The best SIR is the UAV system with a directional antenna in asymmetric altitude conditions where the SIR range varies from 4.44db (the minimum coverage) to 52.11dB (maximum coverage). The worst SIR is the UAV system with an omnidirectional antenna in symmetrical height conditions without considering the height of the UAV. We estimate the range of SIR changes for different coverage ranges between 1.39 and 28dB. Factors affecting the SIR values from the most effective to the least, respectively, are coverage range and the antenna type, symmetrical and asymmetric height, and finally, considering or not considering the height of the UAV. Manuscript profile