According to the standard for the GSM for railway（GSM-R） wireless systems in China train control system level 3（CTCS-3）,the control data transfer delay should be no larger than 500 ms with greater ...than99% probability.Coverage of both non-redundant networks and intercross redundant networks and cases of single Mobile terminals（MTs） and redundant MTs on one train are considered,and the corresponding vehicle-ground communication models,delay models,and fault models are constructed.The simulation results confirm that the transfer delay can meet the standard requirements under all cases.In particular,the probability is greater than 99.996% for redundant MTs and networks,and the standard of transfer delay in CTCS-3 will be improved inevitably.
Generalized spatial modulation (GSM) uses n t transmit antenna elements but fewer transmit radio frequency (RF) chains, n rf . Spatial modulation (SM) and spatial multiplexing are special cases of ...GSM with n rf = 1 and n rf = n t , respectively. In GSM, in addition to conveying information bits through nrf conventional modulation symbols (for example, QAM), the indices of the n rf active transmit antennas also convey information bits. In this paper, we investigate GSM for large-scale multiuser MIMO communications on the uplink. Our contributions in this paper include: 1) an average bit error probability (ABEP) analysis for maximum-likelihood detection in multiuser GSM-MIMO on the uplink, where we derive an upper bound on the ABEP, and 2) low-complexity algorithms for GSM-MIMO signal detection and channel estimation at the base station receiver based on message passing. The analytical upper bounds on the ABEP are found to be tight at moderate to high signal-to-noise ratios (SNR). The proposed receiver algorithms are found to scale very well in complexity while achieving near-optimal performance in large dimensions. Simulation results show that, for the same spectral efficiency, multiuser GSM-MIMO can outperform multiuser SM-MIMO as well as conventional multiuser MIMO, by about 2 to 9 dB at a bit error rate of 10 -3 . Such SNR gains in GSM-MIMO compared to SM-MIMO and conventional MIMO can be attributed to the fact that, because of a larger number of spatial index bits, GSM-MIMO can use a lower-order QAM alphabet which is more power efficient.
Generalized spatial modulation (GSM) uses N antenna elements but fewer radio frequency (RF) chains (R) at the transmitter. In GSM, apart from conveying information bits through R modulation symbols, ...information bits are also conveyed through the indices of the R active transmit antennas. In this letter, we derive lower and upper bounds on the the capacity of a (N, M, R)-GSM MIMO system, where M is the number of receive antennas. Further, we propose a computationally efficient GSM encoding method and a message passing-based low-complexity detection algorithm suited for large-scale GSM-MIMO systems.
Although deep neural networks (DNNs) have been widely applied to hyperspectral image (HSI) denoising, most DNN-based HSI denoising methods are designed by stacking convolution layer, which can only ...model and reason local relations, and thus ignore the global contextual information. To address this issue, we propose a deep spatial-spectral global reasoning network to consider both the local and global information for HSI noise removal. Specifically, two novel modules are proposed to model and reason global relational information. The first one aims to model global spatial relations between pixels in feature maps, and the second one models the global relations across the channels. Compared to traditional convolution operations, the two proposed modules enable the network to extract representations from new dimensions. For the HSI denoising task, the two modules, as well as the densely connected structures, are embedded into the U-Net architecture. Thus, the new-designed global reasoning network can help tackle complex noise by exploiting multiple representations, e.g., hierarchical local feature, global spatial coherence, cross-channel correlation, and multi-scale abstract representation. Experiments on both synthetic and real HSI data demonstrate that our proposed network can obtain comparable or even better denoising results than other state-of-the-art methods.
On Media-Based Modulation Using RF Mirrors Naresh, Yalagala; Chockalingam, Ananthanarayanan
IEEE transactions on vehicular technology,
06/2017, Volume:
66, Issue:
6
Journal Article
Peer reviewed
Media-based modulation (MBM) is a recently proposed modulation scheme that uses radio frequency (RF) mirrors at the transmit antenna(s) to create different channel fade realizations based on their ...ON/OFF status. These complex fade realizations constitute the modulation alphabet. MBM has the advantage of increased spectral efficiency and performance. In this paper, we investigate the performance of some physical layer techniques when applied to MBM. Particularly, we study the performance of1) MBM with generalized spatial modulation (GSM), 2) MBM with mirror activation pattern (MAP) selection based on a Euclidean distance (ED)-based metric, and 3) MBM with feedback-based phase compensation and constellation rotation (PC-CR). Our results show that for the same spectral efficiency, GSM-MBM can achieve better performance compared to MIMO-MBM. Also, it is found that MBM with ED-based MAP selection results in improved bit error performance, and that phase compensation and MBM constellation rotation increases the ED between the MBM constellation points and improves the performance significantly. We also analyze the diversity orders achieved by the ED-based MAP selection scheme and the PC-CR scheme. The diversity orders predicted by the analysis are validated through simulations.
El Sistema Global de Comunicaciones Móviles (GSM) ha tenido una gran aceptación alrededor del mundo. Para implementar estos sistemas era necesario utilizar equipos de costo elevado, sin embargo, ...gracias al desarrollo de sistemas de radios definidos por software, es posible desarrollar este tipo de redes con un costo reducido. El acceso a servicios de telecomunicaciones en comunidades rurales de Cuba es hoy en día un gran reto, propiciado principalmente, por la ubicación geográfica y el reducido número de habitantes que hacen que el despliegue de infraestructura no sea económicamente factible. Las contribuciones principales del presente trabajo son un sistema celular alternativo y software de administración de red GSM. Quedó demostrado que es posible la construcción de una red telefónica móvil usando componentes de software libre y hardware de bajo costo, que pueden ser empleados en comunidades rurales de poca población, así como en situaciones de emergencia.
The Global System for Mobile Communications (GSM) has been widely accepted around the world. The implementation of this system for a comunity are expensive because to use high-cost equipment, but ...thanks to the development of software-defined radio systems, it is possible to develop this type of network at a reduced cost. Access to telecommunications services in rural communities in Cuba is today a great challenge, mainly caused by the geographical location and the small number of habitants that make the deployment of infrastructure not economically feasible. The main contributions of the present work focus in an alternative cellular system and GSM network management software. It was shown that it is possible to build a mobile telephone network using free software components and low-cost hardware, which can be used in sparsely populated rural communities, as well as in emergency situations.
In this paper, we propose to use spatial modulation (SM) and the generalized spatial modulation (GSM) MIMO schemes in indoor line-of-sight (LOS) millimeter-wave (mmWave) communication at 60GHz. ...SM/GSM are known but only at low-GHz frequencies where the channels are typically rich scattered and characterized by Rayleigh or Rician distribution. However, 60-GHz indoor channels are typically not rich but rather sparsely scattered and dominated by the LOS component, thus making them different from low-GHz fading channels and our work novel. We first seek to optimize SM in LOS by finding the channel conditions that minimize its symbol error probability (SEP). Then, we extend our studies to LOS GSM and derive its channel capacity and SEP. Furthermore, we present numerical studies on the behavior and performance of SM/GSM in LOS. LOS spatial multiplexing and beamforming MIMO schemes are used as benchmarks for comparison. At last, we propose novel TX and RX hardware architectures, both of which use only a single RF chain, for implementation of SM/GSM at mmWave frequencies. Both simplicity and good performance are exhibited by LOS SM/GSM thus making them very attractive techniques for short-range indoor mmWave communications at 60GHz.
This article proposes a single-layer, dual-band, optically transparent frequency-selective surface (FSS) for GSM shielding. The design evolves from a fractal cross dipole to achieve dual-band ...response, polarization insensitivity, and wide angle of incidence stability with a miniaturized size. A two-axis symmetric structure helps to provide a stable frequency response for incident waves with different polarization angles up to 60°. Capacitive loading further reduces the unit size and extends the maximum stable incident angle. The working mechanism of the design has been explained through an equivalent lumped element circuit model (ECM), which provides a generic approach to retune or optimize the design for another frequency band. Both the full-wave EM and circuit simulations are in good agreement. A prototype has been realized by screen printing a custom silver nanowire (Ag NW)-based transparent ink on a flexible polymer substrate. A decent reflection performance has been achieved from 0.71 to 1.25 GHz and from 1.73 to 2.16 GHz in measurements, which are consistent with the simulations. Optical measurements reveal a transparency of 81.6%. Printed FSS is completely flexible, and the performance does not deteriorate after bent or rolled up conditions. Field testing on a glass box demonstrates decent shielding from the incoming GSM signals. The highly transparent and flexible nature of the FSS structure makes it suitable for mounting on glass windows of cars or home environments for EM shielding purposes.
This letter proposes a novel joint data mapping generalized spatial modulation (JDM-GSM) scheme to remove the restriction on the number of active transmit-antenna (TA) combinations in conventional ...GSM systems. By increasing the number of active TA combinations, the constellation size for signal mapping can be reduced. Consequently, the overall bit error rate (BER) performance of the GSM system can be improved. To reduce the complexity of optimal maximum-likelihood (ML) detector, a joint compressed sensing (JCS) detector for JDM-GSM scheme is proposed. Simulation results and theoretical analysis show that the proposed scheme can be adapted to multiple-input multiple-output (MIMO) systems and achieves better BER performance than that of the conventional GSM.
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