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Spatial modulation (SM) combined with spatial multiplexing is a newly developed transmission technique in multiple-input multiple-output (MIMO) systems. The resultant system, referred to as SM-MIMO, can use the maximum-likelihood (ML) detector jointly detecting the antenna index and symbol vector. As known, the ML detector can achieve optimum performance; however, its computational complexity may...
A distributed antenna system, where antennas at a base station are spatially distributed over the cell, can improve throughput at the cell edge compared to a centralized antenna system. However, the peak capacity degrades when a remote antenna unit has a few antenna elements due to rank deficiency. In general, the number of antennas at the base station is limited by the number of pilot sequences....
Lattice reduction (LR) is a powerful technique for improving the performance of linear MIMO detection methods. The efficient LR algorithms can largely improve the performance of the linear detectors (LDs). However, there are two problems involved in the LR-aided detection algorithms. One is that, the reduced basis is still not orthogonal, and most existing LR-aided algorithms devote to find a near...
This work introduces efficient schemes for adaptive vertical downtilt beamforming in Long Term Evolution Advanced (LTE-A) networks equipped with active antenna systems (AAS). A framework to determine cell-specific downtilt angles is proposed and solutions are provided with affordable complexities for practical applications. Instead of utilizing a single fixed downtilt, a cell-specific downtilt is...
Leaky coaxial cables (LCX) have been widely used as antennas to form linear service areas for radio communication systems. Such services of linear cells have been deployed inside tunnels, along railways, and so on. Usually, one LCX is utilized as one antenna. Therefore it requires more than one LCX to configure an multi-input multi-output (MIMO) system. In this paper, we propose a MIMO system using...
We have recently introduced adaptive spatial modulation (ASM) [1], which comprises both adaptive modulation (AM) and spatial modulation (SM), with the aim of enhancing the average spectral efficiency (ASE) of multiple antenna systems. This technique was shown to offer high energy efficiency and low system complexity thanks to the use of SM while achieving high data rates thanks to the use of AM. Motivated...
In order to support high data rate communications, the third generation partnership project (3GPP) long term evolution (LTE) implements multiple-input multiple-output (MIMO) systems. In addition, to achieve excellent performance, LTE also employs turbo codes as the forward error correcting (FEC) standard. Although conventional turbo codes give satisfactory performance in the ideal MIMO, significant...
In MIMO space division multiplexing (SDM) systems, the peak power of the transmit signal at each antenna element is increased by the precoder and hence it causes the power efficiency degradation and/or nonlinear distortion at the power amplifier. To solve this problem, this paper present a peak power aware precoding scheme for MIMO-SDM systems, where the precoder is designed to mitigate the peak output...
In this paper, distributed antenna selection algorithms are proposed to improve uncoded bit-error-rate (BER) in multiple-input multiple-output (MIMO) interference channels. The well known distributed power control algorithm by Yates in 1995 is used in all proposed schemes together with distributed antenna search algorithms, explicitly distributed exhaustive search, relaxed exhaustive search, and cross-entropy...
In this paper, we discuss the precoding schemes for coordinated multi-point (CoMP) joint processing (JP) using geometric mean decomposition (GMD). Unlike JP singular value decomposition (JP-SVD) whose performance is dominated by the spatial pipe with weak channel gain, JP-GMD is proposed to derive the precoding matrix of all the cooperative cell sites and the decoding matrix of the user equipment...
In this paper, we analyze the performance of a multiple-input multiple-output (MIMO) multi-hop relay network using transmit antenna selection and maximal ratio combining (TAS/MRC) employing amplify-and-forward relay mode over a Rayleigh fading channels in the presence of Poisson field of interferers, that is applied practically in current cellular networks like LTE (Long Term Evolution). The aggregated...
In this paper, we study a multiuser indoor Terahertz (THz) communication system with antenna array. To capture the distance-frequency dependent peculiarities of THz channels, we design a distance-aware multi-carrier transmission scheme with hybrid beamforming and antenna subarray selection. Specifically, a low complexity greedy subarray selection algorithm is proposed. Simulation results are provided...
The performance of amplify-and-forward (AF) multi-way relay networks (MWRNs) with very large relay antenna arrays is investigated. Asymptotic signal-to-interference-plus-noise ratio (SINR) expressions are derived when the number of antennas at the relay is substantially higher than the number of user nodes. These asymptotic SINRs are independent of the fast fading component of the wireless channel,...
In order to tackle rapidly increasing traffic, the 5th generation (5G) mobile communication system will introduce small cells using higher frequency bands with wider bandwidth to achieve super high bit rate transmission of several tens Gbps. Massive MIMO beamforming (BF) is one of promising technologies to compensate for larger path-loss in the higher frequency bands. Joint analog fixed BF and digital...
This paper presents a framework for coverage and capacity optimization (CCO) in Heterogeneous Cellular Networks (HCNs). Unlike conventional approaches, we propose a concept of effective capacity (EC) as the optimization objective of CCO, which involves the index of coverage in the form of truncation function. The optimization objective is a NP problem due to that the adjusting parameters are mixed...
A framework is presented for performance analysis of 3GPP LTE with detailed modeling of PHY, MAC and RLC protocol layers taking decode-and-forward relays and small cells into account. CDFs, expected values and percentiles of resource consumption, error ratio and spectral efficiency on various protocol layers are calculated for any grid point and for cells in a multi-cell scenario, respectively. Association...
Visualization of stomach and small intestine, nowadays can be done with wireless capsule endoscopy. However, the limitation of bandwidth at low frequencies such as Industrial, Scientific and Medical (ISM) band and Medical Implant Communication Service (MICS) band do not provide high resolution images. One of the possible frequency band to have clear images from digestive organs is the use of Ultra...
IR-UWB communication systems have become popular for Wireless Body Area Network (WBAN) applications in recent times. This paper presents the development and testing of an IR-UWB coordinator node that includes an IR-UWB receiver front-end and a Field Programmable Gate Array (FPGA) based controller. The IR-UWB receiver front-end down converts the high frequency (3.5–4.5 GHz) IR-UWB pulses using a mixer...
In recent years, wireless power transfer has been attracting a great deal of attention. In order to realize efficient power transfer, it is necessary to communicate data such as a frequency, required power, or error tolerance. In the proposed system, because of the use of the same antennas for power transmission and data transmission, the frequency response of a channel for the data transmission changes...
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