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Jaya optimization algorithm (JOA) based multiuser detector over generalized-K (GK) fading channels, in the presence of impulsive noise, is presented in this paper to eliminate multiple access interference (MAI) problem. The JOA is used to implement the M-decorrelator with least squares (LS), Huber (HU), Hampel (HA) and modified Hampel (MH) estimators by minimizing the corresponding penalty functions...
Cognitive radio (CR) has been proposed as a promising solution to enhance the spectrum usage efficiency by exploiting underutilized spectral resources in an opportunistic manner [1]. However, a crucial factor in CRs' implementation lies in the spectrum sensing (SS) procedure [2]. During the SS, a CR typically needs to rapidly monitor multiple frequency bands, which demenads very high sampling rate...
This paper investigates setup optimization of Spatial Modulation (SM) systems. Specifically, the optimal pair of the number of the transmit antennas and the modulation order, for a given spectral efficiency, that minimizes the error rate at the receiver has been discussed. Interesting results regarding the behavior of bit error rate and symbol error rate versus different transmitter setups under different...
The ultra-wide band (UWB) technology can be used for low cost and low power applications such as body area networks, IoT based applications, wireless sensor networks and high data rate short range wireless communications. In the UWB literature, non-coherent energy detector (ED) receiver is proposed to reduce receiver implementation complexity by avoiding the complex channel estimation process and...
This paper addresses the problem of blind channel identification under sparse channel condition. Our approach is an extension of the subspace blind channel identification methods. Unlike previous approaches for blind channel identification where the optimization is in least square sense, i.e., the L2 norm, the proposed extension includes the identification of sparse channels and uses the Li norm....
In this paper, we focus on the potential enhancements of the DVB-T2 signaling (L1Post) by the use of newly designed Two-Dimensional Non-Uniform Constellations (2D-NUC). We Base our design on the optimization of the Bit-interleaved Coded Modulation (BICM) capacity, the designed constellations provide a potential performance improvement of 0.55 dB for the overall DVB-T2 signaling performance in high...
Through the expansion of non-Gray-mapping symbols, the pre-FEC and post-FEC Q-factors of the proposed optimized Circle-8QAM outperform Circle-8QAM and Star-8QAM by ∼0.3 dB and ∼0.6dB at the coding rate of 0.8 in experiments.
In the time reversal division multiple access (TRDMA) system, the signal-to-noise ratio (SNR) is boosted and the interuser interference (IUI) is suppressed due to the temporal and spatial focusing effects of the time-reversal (TR) technique. However, since the focusing effects highly depend on the location-specific multipath profile, there exists a strong-weak focusing effect in the TRDMA uplink system...
A protograph-based low-density parity-check (LDPC) code design technique for bandwidth-efficient coded modulation is presented. The approach jointly optimizes the LDPC code node degrees and the mapping of the coded bits to the bit-interleaved coded modulation (BICM) bit-channels. For BICM with uniform input and for BICM with probabilistic shaping, binary-input symmetric-output surrogate channels are...
In this paper, we propose a power allocation strategy for overlay cognitive networks, where each node is equipped with single antenna. Owing to the overly strategy, the secondary user (SU) can help transmitting the primary user's (PU) data and meanwhile can convey itself own data with the superposition coding (SC). We first analyze the bit-error-rate (BER) of the PU and the SU Then, the power allocation...
This paper presents the design of an adaptive channel equalizer which is based on the recently proposed krill herd (KH) algorithm. The channel equalization problem, which is conventionally solved using gradient descent approaches, has been formulated as an evolutionary computing (EC) algorithm based optimization task. The performance of the proposed scheme has been compared with that obtained using...
Differential amplify-and-forward (DAF) cooperative relaying appears to be an attractive strategy for wireless networks where channel estimation is not feasible or it is rather avoided. In this work, we intend to determine the optimum relay location in order to minimize the outage probability of the DAF cooperative relaying in case that the system is allowed to deploy the relay. We consider two scenarios...
This paper considers the spectrum sharing multiple-input multiple-output (MIMO) cognitive radio network, in which single primary user (PU) coexists with multiple secondary users (SUs). Instead of solving the single-objective optimization prob-lem, we strive to jointly maximizes the number of served SUs and enhances the transmit rate of secondary links with the transmit power and interference temperature...
This paper addresses adaptive modulation and power allocation for maximizing the practicable sum capacity (sum of the uncoded throughputs of the users) of a multiuser multiple-input single-output MU-MISO) system. Since the optimal solution, dirty paper encoding (DPC), is complicated to implement, we use the simpler linear precoding based on signal- to-leakage-plus-noise ratio (SLNR). For different...
We propose a new bit-interleaved coded modulation (BICM)-based cooperative communication system where different BICM modules can be optimized jointly considering the average signal to noise ratios of the direct and the two-hop Rayleigh fading channels. As such, the full benefit of BICM can be exploited in the context of cooperative communication. Our design considers cooperative communication systems...
In this paper, a new partial power and rate adaptation scheme for orthogonal frequency division multiplexing (OFDM) systems is proposed in the presence of carrier frequency offset (CFO). The conventional adaptive scheme is shown to be a special case of the partially adaptive scheme technique which enables the resulting non-convex optimization problem, solved in a feasible way. It leads to a solution...
The K user interference alignment scheme with symbol extensions proposed by Cadambe and Jafar achieves K/2 degree of freedom in theory for high signal-to-noise ratios (SNRs). However, lower SNR ranges appear in many practical scenarios. Thus, further improvements of the Cadambe-Jafar scheme are demanded to enable interference alignment in more realistic settings. In this work, we propose a new precoding...
The main challenge for Cognitive Radio Networks (CRNs) is avoiding interference with PUs caused by unlicensed access, especially in any disaster where the Cognitive Radio (CR) nodes may lose the connection to the data base entity. To cope with this challenge, each CR node depends on its observations, such as Signal to Noise Ratio (SNR) and Signal Strength (SS), to define the free channel. However,...
In this paper, we propose a novel rateless code with unequal error protection (UEP) property based on recently proposed analog fountain codes (AFCs). AFCs have been originally designed and optimized to approach the capacity of a Gaussian channel in a wide range of signal to noise ratios (SNRs). In this paper, we are particularly interested in the UEP property of AFC codes, providing different levels...
In this paper, we study allocation of power and modulation order (rate) to secondary users in a competitive cognitive radio network (CRN). In a competitive CRN, multiple secondary users share a single channel and multiple channels are simultaneously used by a single secondary user (SU) to satisfy their rate requirements [1]. In such an environment, we compute optimal power and modulation order choices...
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