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High fluctuation of signal strength is evident in wireless channel under mobile environment. IEEE 802.11n and IEEE 802.11ac based wireless technologies experience a challenge for selecting link configuration parameters, like number of spatial streams, channel bonding, advanced modulation and coding schemes, frame aggregation etc., dynamically under mobility. Selection of the best possible data rate...
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...
In this paper, a dual-element MIMO antenna without adding any decoupling structure is presented. The MIMO antenna consists of two symmetric inverted-L elements with the antenna spacing of only 9 mm (0.1 λ at 3.5 GHz). The isolation between antennas is reduced by pattern diversity. |S11| < −10 dB and |S21| < −16 dB are achieved over the band from 3.48–3.6 GHz. Compared with the antenna without...
The aim of this paper is to introduce the measurement method for challenging Non-Line of Sight (NLOS) conditions in mobile networks. The need to develop the measurement method appeared LTE (Long Term Evolution) uplink (UL) performance with different antenna technologies when receiving NLOS signal in field tests. Many challenges appeared during the study. This paper introduces the challenges and presents...
This paper proposes a new exponential based packet scheduling scheme for real time traffic in satellite Long Term Evolution (S-LTE) network which adopts MIMO technology. The S-LTE air interface is able to complement its terrestrial counterparts since it's able to provide worldwide coverage and higher data rate especially in the provision of real time services (multimedia services) to mobile users...
A MIMO antenna system comprising of two antenna elements is proposed for utilization in Long Term Evolution (LTE) frequencies for mobile terminals. The antenna element is a coupled fed printed monopole capable of functioning at LTE 2300 on a printed circuit board. The antennas are located symmetrically on the top side of the circuit board. The substrate used here is FR4 which possesses a relative...
Spectral efficiency and capacity of Land Mobile Satellite (LMS) systems can be enhanced by using MIMO (Multiple Input Multiple Output). Polarization diversity is an efficient technique to realize MIMO in LMS communications. Polarization diversity employs different polarization to realize multiple independent propagation paths. Dual polarized antennas offer a space and cost effective alternative compared...
Massive multiple-input multiple-output (MIMO) is an emerging technology for future wireless networks, scaling up conventional MIMO to an unprecedented number of antennas at base stations. Such a large antenna array has the potential to make the system achieve high channel capacity and spectral efficiency, but it also leads to high cost in terms of hardware complexity. In this paper, we consider a...
Wireless communications is one of the fastest growing technology fields, driving numerous other innovations in electronics. One challenging research area within the wireless field is to achieve a higher transmission speed. Today it is an open question how we can realize a wireless system at a speed of 100 Gb/s or even beyond. If we intend to use such systems in a mobile environment, we can only afford...
In this paper, the measurement results of field experiments for correlation reduction precoding with a repetition code in an overloaded MIMO systems are presented. Measurements are conducted in three propagation conditions that are line-of-sight (LOS), non-line-of- sight (NLOS), and a mobile environment. Numerical results obtained through the measurements show that amplitude shift and phase rotation...
It is necessary to study the spatial evolution of clusters in massive multiple-input multiple-output (MIMO) mobile channel, which is one of the important features in cluster-based models. In this paper, we analyze the data collected from the massive MIMO mobile measurement campaign, with a 256-element virtual array at 3.5 GHz in line of sight (LoS) and non line of sight (NLoS) conditions, respectively...
By calculating the effective max-min SINR (signal- to-interference-plus-noise ratio) and the corresponding power controls explicitly, and selectively dropping a small number of mobiles based on a simple and effective algorithm, we demonstrate that for both downlink and uplink, employing maximum-ratio or zero-forcing linear pre-coding and de-coding, Massive MIMO with max- min power control performs...
Recently, the use of unmanned aerial vehicle (UAV) is going to receive great interest in various areas. As a newly emerging area, UAV-aided communications encounter unique communication scenarios and thus need corresponding UAV channel models for better design of such UAV communication systems. In this paper, we propose a three-dimensional (3D) sphere UAV air-to-ground (A2G) multiple-input-multiple-output...
Massive Multiple-input Multiple-output (MIMO) adaption is one of the primary evolving objectives for the next generation high speed train (HST) communication system. In this paper, we consider how to design an efficient low-complexity location-aware beamforming for the multi-user (MU) massive MIMO system in HST scenario. We first put forward a lowcomplexity beamforming based on location information,...
Device-to-Device (D2D) communication has drawn great interest in academia and industries due to the extended network coverage and reduction of the restrictions of traditional cellular systems. On the other hand, a new paradigm called content-centric networking (CCN) has been proposed for scalable, flexible, and secure services in the future networks. With CCN, it is possible to increase the throughput...
In this paper, we study upper bounds on the sum capacity of the downlink multicell processing model with finite backhaul capacity for the simple case of 2 base stations and 2 mobile users. It is modeled as a two-user multiple access diamond channel. It consists of a first hop from the central processor to the base stations via orthogonal links of finite capacity, and the second hop from the base stations...
In this paper, we investigate the prediction of mobile MIMO channels with varying multipath parameters. Based on the PAST algorithm, we propose a multidimensional adaptive ESPRIT approach for jointly tracking the evolution of the Doppler frequencies and spatial directions of arrival and departure of the propagation paths. Future states of the channel are predicted using the last estimate of the propagation...
We derive a closed-form expression for the throughput in the uplink of a cooperative massive MIMO system. We consider a network where a cluster of base stations co-operate to detect signals from mobiles using a linear minimum-mean-square error receiver. A user-centric clustering approach is assumed, where the cluster that detects the signals from each mobile is composed of the K base stations that...
Long Term Evolution (LTE) technology gives access to higher bandwidth and assures efficiency at network level for telecommunication operators, providing a reliable and continuous data traffic flow that allows data transmission at extremely high bit-rates. The aim of this paper is to evaluate LTE network performance in an actual urban environment, with emphasis on the downlink channel throughput. The...
Multi-beam mobile satellite systems aim at providing broadband and high speed mobile services over a large area to achieve a high system throughput, where hybrid space-ground beamforming is one of the most promising candidates for ground-based beamforming techniques. It not only reduces the feeder link bandwidth to save spectral resources, but also takes advantages of both the on-ground and on-board...
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