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In this paper, we investigate feasibility of orbital angular momentum (OAM) based analog transmission method. The method uses analog discrete Fourier transform (DFT) feed networks for mode generation as well as circular array antenna with right-hand and left-hand circular polarizations. The simulation revealed the designed array antennas enhance the capacity up to double of the single polarization...
Interference alignment has triggered high impact research in wireless communications since it was proposed nearly 10 years ago. However, the vast majority of research is centered on the theory of interference alignment and is hardly feasible in view of the existing state-of-the-art wireless technologies. Although several research groups have assessed the feasibility of interference alignment via testbed...
Multiple-input multiple-output (MIMO) and cooperative communications have been attracted great attention for the improvements of communication capacity, power consumption, and transmission coverage. The conventional fixed relaying protocols, amplify-and-forward (AF) and decode-and-forward (DF), have their own advantages and disadvantages, i.e. AF performs better than DF for low signal-to-noise ratio...
This paper considers a frequency-division-duplexing (FDD) massive multiple-input multiple-output (MIMO) system that operates with two-stage beamforming based on user grouping. In this system, we propose a first stage beamformer and a user grouping method for the two-stage beamforming. The proposed first stage beamformer maximizes an approximate sum rate calculated from the second-order statistic of...
Massive MIMO technology is needed as the volume of data demand increases. An increase in the number of RF-chains as the number of antennas increases causes hardware complexity and system cost increase. This causes the application of the actual communication system to be delayed. In this paper, we show the applicability to massive mimo by expanding the unit load modulation module with single RF-chain...
Large scale multiple input multiple output (MIMO), commonly referred to as massive MIMO, is one of the most important physical layer disruptions in network evolution that would lead to significant increase in spectral and energy efficiency envisioned for 5G networks. However, the computational complexity of massive MIMO system becomes the key problem for its practical implementation. As known, Differential...
The emerging market of the Internet of Things (IoT) requires new energy-efficient and low-complexity Multiple-Input-Multiple-Output (MIMO-) aided radio access technologies. This trend will have a profound impact on both the theory and practice of future communication networks, which will not be purely optimized for approaching the attainable capacity anymore, but will explicitly include the energy...
By combining the polarized modulation and the spatial modulation technique, dual-polarized spatial modulation (DPSM) has been recently proposed for MIMO transmission to improve the spectral efficiency and reduce the space occupancy. The performance of DPSM over correlated Rayleigh and Rice fading channels has been studied, showing that DPSM technique outperforms uni-polarized SM technique. For a general...
The main objective of this paper is to develop an efficient satellite digital beam-forming (BF) method that can provide user specific desirable signal-to-interference-plus-noise ratio (SINR) or data rate for each user in each zone. And a massive multiple-input multiple-output (MIMO) communications system model and its favorable channel propagation condition are assumed (i.e., channel independence...
Full-duplex (FD) multiple-input multiple-output (MIMO) systems can achieve simultaneous transmission and reception at the same frequency. In this paper, the FD MIMO system, where the multi-tap (MT) canceller is adopted to eliminate the self-interference (SI) with imperfect SI channel state information, is studied. Considering the dynamic range of the analog-to-digital converter and the linearity of...
A simple technique to design MIMO space-time block codes that achieve both diversity and rate gains is to stack spatial multiplexing (V-BLAST) and transmit diversity (Alam-outi) encoders; these are known as hybrid codes. We increase the spectral efficiency of a simple hybrid code with one V-BLAST layer and one Alamouti layer by using spatial modulation. In spatial modulation systems, information is...
Motivated by large capacity gains in multiple antenna systems when ideal channel state information (CSI) is available at both receiver and transmitter when quadrature amplitude modulation (QAM) modulation is applied, we examine the achievable rates of Rayleigh fading channel measurement based optimization techniques. We consider complex-valued AWGN noise and try to determine the optimal input distribution...
In this paper, we propose two novel fiber-optic relaying schemes, one using SM technology and another using STBC and MRC diversity reception technologies, for MIMO mobile transmission. Using single RoF link to relay MIMO signals, the proposed schemes have much lower system complexity and cost than the conventional RoF relaying system. Computer simulation confirmed that the proposed SM-RoF scheme has...
Coverage at millimeter-wave (mmW) frequencies is a constraining bottleneck. Spatial diversity and spatial multiplexing multiple-input multiple-output (MIMO) improve performance over a spread of user locations and these can benefit from wider antenna spacing. Radio-over-Fiber (RoF) transport provides flexibility in deploying a number of widely-spaced Remote Antenna Units (RAUs) connected to the same...
We consider an antenna selection scheme in single-user massive MIMO systems. We formulate a rate maximization problem with a sparsity promoting regularization function. The proposed algorithm allocates sparse power allocation among transmit antennas. It achieves a very high sum rate close to the optimal full search algorithm.
We introduce a low-complexity layered iterative sampling algorithm for near-optimal detection in uplink massive multiple-input multiple-output (MIMO) systems based on the Gibbs sampling. In contrast to the most of Gibbs-sampling-based detectors in the previous arts, which assuming the numbers of transmitting and receiving antennas are similar, in this paper we assume the number of receiving antennas...
This paper proposes a novel beam domain peak-to-average power ratio (PAPR) reduction scheme, named idle beam exploitation (IBE), in multi-beam systems, i.e., massive multi-input multi-output (MIMO) downlink based on angle division multiple access (ADMA) here. To some extent, PAPR consideration in multi-beam systems is similar to that in multi-carrier systems, and PAPR reduction methods in multi-beam...
Channel state information (CSI) is essential for realizing the benefits of massive MIMO systems, but the pilot overhead for acquisition the CSI is tremendous, especially for frequency division duplex (FDD) massive MIMO systems. In order to reduce the pilot overhead, we propose a decoupling pilot design scheme. The proposed pilot design scheme fully utilizes the channel sparsity in delay-angle domain...
This paper presents an orbit angular momentum (OAM) based wireless communication system combined with multi-input multi-ouput (MIMO) technique, where each MIMO branch multiplexes several OAM signals. The achievable sum-rate and array gain of the OAM-MIMO system relative to pure MIMO are analyzed. Results show that, when at near distance, e.g, the OAM beams are such collimated that each branch suffers...
In this paper, an antenna grouping assisted spatial modulation scheme is proposed for massive MIMO systems. Massive multiple-input-multiple-output (MIMO) systems are capable of offering abundant spatial capacity by deploying hundreds of antennas at the base station (BS). Spatial modulation (SM) is one of the key technologies in exploiting spatial capacity, which maps the information bits to the active...
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