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In a binary input additive white Gaussian noise (BIAWGN) channel, belief propagation (BP) decoding for luby transform (LT) codes requires the knowledge of the signal-to-noise ratio (SNR) at the receiver to achieve its optimal performance. An erroneous estimation of the SNR at the decoder is referred to as “SNR mismatch”. SNR mismatch can significantly degrade the BP decoding performance of LT codes...
The existing algorithms for the selection and switching of signal-code sequences (SCS) in IEEE 802.11 wireless equipment are analyzed. Indicators and criteria for assessing the efficiency of existing SCSs switching algorithms are reviewed. Suggested algorithms for switching SCS are proposed taking into account advantages and disadvantages of such algorithms.
In this paper we analyze adaptive classification algorithm for digital amplitude-phase modulated signals in flat fading channel with non-Gaussian additive noise, representing possible interference in the channel besides thermal receiver noise. We represent additive noise via normal mixture model, which is able to model various interference scenarios by choosing specific mixture parameters. The adaptive...
This paper considers low-complexity transmit beamforming schemes for signal-to-interference-plus- noise ratio (SINR) balancing problem in the Gaussian multiple-input single-output multi-receiver wiretap channel (MISO-MRWC). The formulated max-min-fair problem are shown to be non-convex. To overcome the computational complexity, we develop the leakage-based and zero forcing (ZF) based beamforming algorithms...
The integer-forcing (IF) linear multiple-input and multiple-output (MIMO) receiver is a recently proposed suboptimal receiver which nearly reaches the performance of the optimal maximum likelihood receiver for the entire signal-to-noise ratio (SNR) range and achieves the optimal diversity multiplexing tradeoff for the standard MIMO channel with no coding across transmit antennas in the high SNR regime...
In this paper, the comparison of several optimization methods for solving the optimal multiuser detection problem exactly or approximately are discussed. The purpose of using these algorithms is to provide complexity constraint alternatives to solving this nondeterministic polynomial-time (NP)-hard problem. An approximate solution is found firefly based optimization which is used to provide an exact...
We introduce maximum-SINR sparse-binary waveforms that modulate data information symbols from any finite alphabet and span the whole continuum of the available/device-accessible spectrum. We offer an optimal algorithm that designs the proposed waveforms by maximizing the signal-to-interference-plus-noise ratio (SINR) at the output of the maximum-SINR linear receiver. In addition, we offer a suboptimal...
Modern mobile terminals produce massive small data packets. For these short-length packets, it is inefficient to follow the current multiple access schemes to allocate transmission resources due to heavy signaling overhead. We propose a many-access scheme that is well suited for the future communication systems equipped with many receive antennas. The system is modeled as having a block-sparsity pattern...
In this paper, a joint linear pre-coder and combiner optimization scheme is proposed to reduce the multi- user interference in the distributed antenna system (DAS). The pre-coder is designed based on the modified weighted signal-to-caused interference ratio (SCIR) which considers the interference on others caused by the desired user and the users channel condition. And the combiner is chosen based...
Consensus-based algorithms are a welcome approach to establish cooperative communication systems. In this work, it has been utilized to present a hardware architecture for distributed data detection in a receiver with several sensor nodes on an easily scalable regular network. Additionally, it is capable to detect the transmitted message even if a single sensor node fails to operate. On top of that,...
A novel efficient blind estimation method is proposed for long-code direct sequences spread spectrum signals. The core idea of the proposed method is to construct an information symbol transition pattern matrix to eliminate the information symbol time varying damage to the periodic structure of pseudo-noise sequences for long-code DSSS signals. Then eigenanalysis approach is employed to estimate the...
This paper presents a target localization problem based on the time difference of arrival (TDOA) measurements by employing an improved genetic algorithm (GA) for estimation. The weighted least square (WLS) technique is applied as an efficient existing approach. The TDOA target localization problem is formulated as an optimization problem, with a highly nonlinear and multimodal objective function....
Anti-jamming interference alignment (IA) algorithm is an effective method to battle with adversarial jammers. Nevertheless, the abundant power from the jammers and interferences can be harvested by the legitimate users as a natural power supply. In this paper, we propose a novel anti-jamming IA scheme with wireless energy harvesting (EH). In the scheme, the power partition coefficient and transmit...
This work considers methods to detect unknown signals in cognitive radio networks. These methods can be applied when taking decision about presence of a signal in the frequency channel when monitoring radio spectrum. The problem of uncertainty can appear when monitoring spectrum. A way of overcoming a priori uncertainty that arises when monitoring the radio spectrum is proposed.
The use of energy harvesting wireless sensor network (EH-WSN) is a rising wireless communication technology with a wide range of applications such as environment monitoring. Maximizing the number of samples collected by the sink from sensors is a key approach in order to minimize uncertainties for those applications. The considered system in this paper consists of an uplink scenario with EH sensors...
Due to the tiny wavelength of millimeter waves (mmWave), tens of antennas can be packed into a small area in mmWave transceivers. However, implementing a radio-frequency (RF) chain for each antenna is impractical due to the high cost and power of mixed-signal devices. To reduce the cost and get benefit from the antennas, an analog RF beamformer is implemented using variable gain amplifiers and analog...
In this paper, an optimal link selection and data rate assignment algorithm for spatial time division multiple access (STDMA) medium access control (MAC) protocols is exploited. The motivation for this study is jointly searching for optimal links and corresponding rates in simultaneous transmission environments in order to maximize the throughput capacity in each time slot. A mathematical formulation...
For a given set of communication links whose senders transmit at a fixed power level, it is a hot problem to select a maximum set of links that can be transmitted simultaneously, which is known to be NP-hard. The existing algorithm only apply to the condition of omnidirectional transmission. This paper addresses the problem in a plane wireless network where the nodes use directional antennas under...
In this paper, an alternative jointly optimized transceiver scheme is proposed to reduce the multi-user interference in the distributed antenna system (DAS). First a joint design for the pre-coders and combiners is proposed based on the signal-to-leakage-plus-noise ratio (SLNR) maximization and the receive signal-to-interference-plus-noise ratio (SINR) maximization, respectively. Then a modified weighted...
Channel estimation in wireless communication system using various supervised learning algorithms traditionally involves two very popular algorithms namely Least Mean Square (LMS) and Recursive Least Square (RLS). The concept of variable step size adaptive algorithms came into picture later on to achieve a trade-off between convergence speed and mathematical complexity of these two algorithms (LMS...
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