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Since radio links in wireless body area networks (WBANs) commonly experience highly time-varying attenuation due to topology instability, communication protocols with fixed transmission power cannot produce a very good performance in terms of energy consumption, interference range, and communication reliability. We explain that how channel behaviourcan be modelled using Markov Chain. Then, a power-adaptive...
The performance of massive multiple-input multiple-output (MIMO) systems is heavily affected by pilot contamination. This paper considers the problem of pilot contamination in massive MIMO systems, and investigates the normalized mean square error (NMSE) of the minimum mean square error (MMSE) channel estimation algorithm in the presence of pilot contamination. An effective uplink training strategy...
This paper analyzes secrecy outage probability (SOP) of underlay cognitive radio systems (UCRSs) interfered by signals from primary networks, impaired by channel information inaccuracy and Rayleigh fading, constrained by peak transmit power and tolerable interference power. The analytical result is presented in an exact expression and corroborated by computer simulations. Multiple results illustrate...
In this paper, we design a fully non-orthogonal communication framework for spectral-efficient massive access. Firstly, we propose a non-orthogonal channel estimation (NOCE) method, which can achieve a balance between channel state information (CSI) accuracy and the length of pilot sequence. Then, we present a massive multiple-input multiple-out (MIMO) non-orthogonal multiple access (NOMA) scheme...
In this paper, a novel pilot extension scheme is proposed for massive MIMO uplink transmission, and its performance is evaluated analytically. Specifically, we divide the cell users into two groups, namely near users and far users, according to their distances to the service base stations. The far users are more motivated to mitigate the inter-cell interference than the near users at the price of...
In this paper, we propose two uplink pilot power control schemes to mitigate pilot contamination in a multi-cell massive multiple-input multiple-output (MIMO) system. These uplink pilot power control schemes can maximize the minimum signal-to-interference-plus-noise ratio (SINR) of the worst user or the mean SINR of the whole network for the downlink data transmission. Combinatorial optimization problems...
A problem that arises with pilot assignment in multicellular massive multiple-input-multiple-output (MIMO) systems is due to inter-cell interference, also known as pilot contamination. This paper focuses on minimizing the inter-cell interference that results from spatial correlation based on signal arrival parameters, assuming the use of a cylindrical antenna array. The signal parameters are used...
In most industrial processes transfer of data and software from or to sensors is an essential part of the monitoring and control systems. Many of the older, wired communication systems have been or are being replaced with wireless alternatives. A number of challenges are associated with this replacement: Radio receivers are subject to interference from other radio sources. Similarly, radio transmitters...
This paper investigates user selection and power allocation algorithms in multi-cell massive Multiple-Input Multiple-Output (MIMO) systems. The focus is on designing an algorithm that maximizes a particular cell of interest's sum rate taking into consideration the interference from other cells. This research extends previous work and proposes suboptimal per cell resource allocation models that are...
This paper presents pilot symbol aided channel estimation in Filter Bank Multicarrier (FBMC). FBMC has been employed widespread in communication applications because of its good spectral behaviors. Unlike Orthogonal Frequency Division Multiplexing, FBMC structure avoids imaginary interference. So that auxiliary symbols are employed and decrease peak to power ratio and improve achievable capacity....
Growing demands of high-quality data rate, coverage area, latency and efficient resource management in the heterogeneous network are addressed by Massive MIMO (M-MIMO) and Heterogeneous Small Cell Network (HSCN). M-MIMO systems with a large number of transceiver antenna arrays achieve high spatial multiplexing. The channel reciprocity is best exploited by linearly increasing the overhead of incoming...
Orthogonal Frequency Division Multiplexing (OFDM) technology is the preferred technique for low voltage power line communication because it can combat the frequency selective fading caused by multi-path transmission effectively. And channel estimation is one of the crucial domains of OFDM. In this paper, an improved Linear Minimum Mean Square Error (LMMSE) method is proposed which chooses the fist...
Filter bank-based multicarrier (FBMC) systems have been considered as a prevalent candidate for replacing the long established cyclic prefix (CP)-based orthogonal frequency division multiplexing (CP-OFDM) in the physical layer of next generation communications systems. In particular, offset quadrature amplitude modulation (OQAM)-based FBMC has received increasing attention due to, among other features,...
We introduce a sensor-aided predictive algorithm for multi-hop link quality estimation. The proposed concept uses vehicle sensor data to improve a link adaptation and end-to-end path selection for a vehicular multi-hop data transmission. The obtained results show that the proposed concept allows better multi-hop link quality estimation and significantly improves end-to-end transmission characteristics...
The performance of full-duplex (FD) decode-and-forward (DF) relaying systems for point-to-point multi-antenna transmission is considered. Three different relaying schemes are investigated: co-located, distributed cooperative and distributed non-cooperative. To mitigate the effects of loop interference (LI) caused by FD operation at the relay, a digital cancellation scheme based on pilot-aided channel...
We consider wireless information and power transfer in a multi-user massive multiple-input multiple-output (MU-Massive-MIMO) system, where several distributed antenna sets, also denoted as remote radio heads (RRHs), are deployed, while the users can simultaneously perform information detection and energy harvesting. Assuming a large number of antennas and autonomous power allocation for the information...
With the growth of mobile data application and the ultimate expectations of 5G technology, the need to expand the capacity of the wireless networks is inevitable. Massive MIMO technique is currently taking a major part of the ongoing research, and expected to be the key player in the new cellular technologies. This papers presents an overview of the major aspects related to massive MIMO design including,...
The Orthogonal Frequency Division Multiplexing (OFDM) is widely used in the wireless communication systems. The robustness in a wireless environment combined with the ease to perform the channel estimation (CE) are the reasons for the OFDM popularity. Commonly, the channel estimation(CE) is performed in frequency domain using pilot tones. It is known that the wireless communications may be affected...
Using OMP algorithm for time-delay detecting and apply BEM based on comb-type pilot for channel estimation is the most commonly used method for sparse time-frequency doubly-selective channels, but the channel estimation performance will decrease sharply when the number of channel paths is large, and this method need to obtain the channel sparsity as prior information in advance. In this paper, a novel...
In this work, we acknowledge the existence of the accumulation of the loopback self-interference when AF protocol is made used of in FDTW relaying and the channel estimation of the loopback channel is not done perfectly as will seen in the section to follow. The accumulation of the loopback self-interference comes from the functionality of FD antenna, which will bring back the transmitted signal to...
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