The Experts below are selected from a list of 35394 Experts worldwide ranked by ideXlab platform
Naoya Wada - One of the best experts on this subject based on the ideXlab platform.
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Demonstration of an SDM Network Testbed for Joint Spatial Circuit and Packet Switching
Photonics, 2018Co-Authors: Ruben S Luis, Benjamin J Puttnam, Hideaki Furukawa, Georg Rademacher, Naoya WadaAbstract:We demonstrate a Spatial Division multiplexing (SDM) network testbed composed of three nodes connected via 19-core multi-core fibers. Each node is capable of joint Spatial circuit switching and joint packet switching to support 10 Tb/s Spatial circuit super channels and 1 Tb/s line rate Spatial packet super channels. The performance of the proposed hybrid network is evaluated, showing successful co-existence of both systems in the same network to provide high capacity and high granularity services. Finally, we demonstrate an optical channel selection associated with the quality of service requirements on the SDM network testbed.
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osnr penalty of self homodyne coherent detection in Spatial Division multiplexing systems
IEEE Photonics Technology Letters, 2014Co-Authors: Ruben S Luis, Benjamin J Puttnam, Jose Manuel Delgado Mendinueta, Werner Klaus, Jun Sakaguchi, Yoshinari Awaji, Tetsuya Kawanishi, Atsushi Kanno, Naoya WadaAbstract:This letter presents a general model for the performance of Spatial-Division-multiplexing systems using self-homodyne detection. The model is applicable to single and dual polarization square M-quadrature amplitude modulation (QAM) signals, assuming arbitrary signal and pilot tone optical signal-to-noise ratios. Its validity is demonstrated using a seven-core multicore fiber link with quadrature phase shift keying and 16-QAM signals, comparing the performance of self-homodyne detection with intradyne detection.
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In-service method of path length alignment in SDM systems with self-homodyne detection
2013 18th OptoElectronics and Communications Conference held jointly with 2013 International Conference on Photonics in Switching, 2013Co-Authors: Ruben S Luis, Benjamin J Puttnam, Jose Manuel Delgado Mendinueta, Werner Klaus, Jun Sakaguchi, Yoshinari Awaji, Atsushi Kanno, Naoya Wada, Tetsuya KawanishiAbstract:An in-service path length alignment subsystem for phase noise cancellation in self-homodyne coherent detection systems is proposed and demonstrated for Spatial Division multiplexing multi-core fiber links. Sub-centimeter resolution is demonstrated with penalties below 0.5dB.
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investigating self homodyne coherent detection in a 19 core Spatial Division multiplexed transmission link
European Conference and Exhibition on Optical Communications, 2012Co-Authors: Benjamin J Puttnam, Jose Manuel Delgado Mendinueta, Werner Klaus, Jun Sakaguchi, Yoshinari Awaji, Atsushi Kanno, Naoya Wada, Tetsuya KawanishiAbstract:We investigate the performance of self-homodyne coherent system based on 19*SDM and 16*WDM channels. We show that self-homodyne detection, with pilot-tone transmitted on 1 MCF core, is compatible with SDM transmission systems but inter-core crosstalk can limit potential advantages.
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world first mode Spatial Division multiplexing in multi core fiber using laguerre gaussian mode
European Conference on Optical Communication, 2011Co-Authors: Yoshinari Awaji, Naoya Wada, Yasunori Toda, Tetsuya HayashiAbstract:We combined multi-core fiber technology and Laguerre-Gaussian mode to explore further increase of transmission capacity. Preservation of orbital angular momentum through multi-core fiber propagation sustained error free transmission of mode/Spatial multiplexed 10 Gb/s channels.
Giuseppe Caire - One of the best experts on this subject based on the ideXlab platform.
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on the achievable rates of fdd massive mimo systems with Spatial channel correlation
International Conference on Communications, 2014Co-Authors: Zhiyuan Jiang, Andreas F. Molisch, Giuseppe Caire, Zhisheng NiuAbstract:In this paper, we study the optimization of the achievable rates of frequency-Division-duplex (FDD) massive multiple-input-multiple-output (MIMO) systems with Spatially correlated channels, by designing the downlink channel training sequences and the uplink channel feedback codebooks. In particular, the optimal channel training sequences and a Karhunen-Loeve transform followed by entropy coded scalar quantization codebook are proposed to optimize the achievable rates. We compare our achievable rates with time-Division-duplex (TDD) massive MIMO systems, i.i.d. FDD systems, and the joint Spatial Division and multiplexing (JSDM) scheme. It is shown that, the rate-gap between FDD systems and TDD systems is significantly narrowed. Compared to the JSDM scheme, our proposal achieves dimensionality-reduction channel estimation without channel pre-projection, and higher throughput in general, though at higher computational complexity.
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joint Spatial Division and multiplexing opportunistic beamforming user grouping and simplified downlink scheduling
IEEE Journal of Selected Topics in Signal Processing, 2014Co-Authors: Ansuman Adhikary, Giuseppe CaireAbstract:Joint Spatial Division and Multiplexing (JSDM) is a downlink multiuser MIMO scheme recently proposed by the authors in order to enable “massive MIMO” gains and simplified system operations for Frequency Division Duplexing (FDD) systems. The key idea lies in partitioning the users into groups with approximately similar channel covariance eigenvectors and serving these groups by using two-stage downlink precoding scheme obtained as the concatenation of a pre-beamforming matrix, that depends only on the channel second-order statistics, with a multiuser MIMO linear precoding matrix, which is a function of the effective channels including pre-beamforming. The role of pre-beamforming is to reduce the dimensionality of the effective channel by exploiting the near-orthogonality of the eigenspaces of the channel covariances of the different user groups. This paper is an extension of our initial work on JSDM, and addresses some important practical issues. First, we focus on the regime of finite number of antennas and large number of users and show that JSDM with simple opportunistic user selection is able to achieve the same scaling law of the system capacity with full channel state information. Next, we consider the large-system regime (both antennas and users growing large) and propose a simple scheme for user grouping in a realistic setting where users have different angles of arrival and angular spreads. Finally, we propose a low-overhead probabilistic scheduling algorithm that selects the users at random with probabilities derived from large-system random matrix analysis. Since only the pre-selected users are required to feedback their channel state information, the proposed scheme realizes important savings in the CSIT feedback.
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Joint Spatial Division and multiplexing for mm-Wave channels
IEEE Journal on Selected Areas in Communications, 2014Co-Authors: Ansuman Adhikary, Ebrahim Al Safadi, Theodore Ted S. Rappaport, Mathew Khalil Samimi, Giuseppe Caire, Rui Wang, Andreas F. MolischAbstract:Massive MIMO systems are well-suited for mm-Wave communications, as large arrays can be built with reasonable form factors, and the high array gains enable reasonable coverage even for outdoor communications. One of the main obstacles for using such systems in frequency-Division duplex mode, namely, the high overhead for the feedback of channel state information (CSI) to the transmitter, can be mitigated by the recently proposed joint Spatial Division and multiplexing (JSDM) algorithm. In this paper, we analyze the performance of this algorithm in some realistic propagation channels that take into account the partial overlap of the angular spectra from different users, as well as the sparsity of mm-Wave channels. We formulate the problem of user grouping for two different objectives, namely, maximizing Spatial multiplexing and maximizing total received power in a graph-theoretic framework. As the resulting problems are numerically difficult, we proposed (sub optimum) greedy algorithms as efficient solution methods. Numerical examples show that the different algorithms may be superior in different settings. We furthermore develop a new, “degenerate” version of JSDM that only requires average CSI at the transmitter and thus greatly reduces the computational burden. Evaluations in propagation channels obtained from ray tracing results, as well as in measured outdoor channels, show that this low-complexity version performs surprisingly well in mm-Wave channels.
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joint Spatial Division and multiplexing opportunistic beamforming and user grouping
arXiv: Information Theory, 2013Co-Authors: Ansuman Adhikary, Giuseppe CaireAbstract:Joint Spatial Division and Multiplexing (JSDM) is a recently proposed scheme to enable massive MIMO like gains and simplified system operations for Frequency Division Duplexing (FDD) systems. The key idea lies in partitioning the users into groups with approximately similar covariances, and use a two stage downlink beamforming: a pre-beamformer that depends on the channel covariances and minimizes interference across groups and a multiuser MIMO precoder for the effective channel after pre-beamforming, to counteract interference within a group. We first focus on the regime of a fixed number of antennas and large number of users, and show that opportunistic beamforming with user selection yields significant gain, and thus, channel correlation may yield a capacity improvement over the uncorrelated "isotropic" channel result of Sharif and Hassibi. We prove that in the presence of different correlations among groups, a block diagonalization approach for the design of pre-beamformers achieves the optimal sum-rate scaling. Next, we consider the regime of large number of antennas and users, where user selection does not provide significant gain. Here, we propose a simplified user grouping algorithm to cluster users into groups when the number of antennas becomes very large, in a realistic setting where users are randomly distributed and have different angles of arrival and angular spreads depending on the propagation environment. Our subsequent analysis leads to a probabilistic scheduling algorithm, where users within each group are preselected at random based on probabilities derived from the large system analysis, depending on the fairness criterion. This is advantageous since only the selected users are required to feedback their channel state information (CSIT).
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Joint Spatial Division and multiplexing-The large-scale array regime
IEEE Transactions on Information Theory, 2013Co-Authors: Ansuman Adhikary, Junyoung Nam, Jae Young Ahn, Giuseppe CaireAbstract:We propose joint Spatial Division and multiplexing (JSDM), an approach to multiuser MIMO downlink that exploits the structure of the correlation of the channel vectors in order to allow for a large number of antennas at the base station while requiring reduced-dimensional channel state information at the transmitter (CSIT). JSDM achieves significant savings both in the downlink training and in the CSIT uplink feedback, thus making the use of large antenna arrays at the base station potentially suitable also for frequency Division duplexing (FDD) systems, for which uplink/downlink channel reciprocity cannot be exploited. In the proposed scheme, the multiuser MIMO downlink precoder is obtained by concatenating a prebeamforming matrix, which depends only on the channel second-order statistics, with a classical multiuser precoder, based on the instantaneous knowledge of the resulting reduced dimensional “effective” channel matrix. We prove a simple condition under which JSDM incurs no loss of optimality with respect to the full CSIT case. For linear uniformly spaced arrays, we show that such condition is approached in the large number of antennas limit. For this case, we use Szego's asymptotic theory of Toeplitz matrices to show that a DFT-based prebeamforming matrix is near-optimal, requiring only coarse information about the users angles of arrival and angular spread. Finally, we extend these ideas to the case of a 2-D base station antenna array, with 3-D beamforming, including multiple beams in the elevation angle direction. We provide guidelines for the prebeamforming optimization and calculate the system spectral efficiency under proportional fairness and max-min fairness criteria, showing extremely attractive performance. Our numerical results are obtained via asymptotic random matrix theory, avoiding lengthy Monte Carlo simulations and providing accurate results for realistic (finite) number of antennas and users.
Jie Zhang - One of the best experts on this subject based on the ideXlab platform.
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design and characterization of 16 mode panda polarization maintaining few mode ring core fiber for Spatial Division multiplexing
Optical Engineering, 2017Co-Authors: Yuan Cao, Yongli Zhao, Jiawei Han, Jie ZhangAbstract:A PANDA polarization-maintaining few-mode ring-core fiber (PM-FM-RCF) structure with two air holes around the ring core is proposed. The relative mode multiplicity factor (RMMF) is defined to evaluate the Spatial efficiency of the designed PM-FM-RCF. The performance analysis and comparison of the proposed PANDA PM-FM-RCFs considering three different types of step-index profiles are detailed. Through modal characteristic analysis and numerical simulation, the PM-FM-RCF with a lower refractive index difference (Δnoi=1.5%) between the ring core and the inner central circle can support up to 16 polarization modes with large RMMF at C-band, which shows the optimum modal properties compared with the PM-FM-RCF with higher Δnoi. All the supported polarization modes are effectively separated from their adjacent polarization modes with effective refractive index differences (Δneff) larger than 10−4, which also show relatively small chromatic dispersion (−20 to 25 ps/nm/km), low attenuation (<1.4 dB/km), and small bending radius (∼8 mm) over the C-band. The designed PM-FM-RCF can be compatible with standard single-mode fibers and applied in multiple-input multiple-output-free Spatial Division multiplexing optical networks for short-reach optical interconnection.
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super channel oriented routing spectrum and core assignment under crosstalk limit in Spatial Division multiplexing elastic optical networks
Optical Fiber Technology, 2017Co-Authors: Yongli Zhao, Chunhui Wang, Xiaosong Yu, Binglin Li, Jie ZhangAbstract:Abstract With the capacity increasing in optical networks enabled by Spatial Division multiplexing (SDM) technology, Spatial Division multiplexing elastic optical networks (SDM-EONs) attract much attention from both academic and industry. Super-channel is an important type of service provisioning in SDM-EONs. This paper focuses on the issue of super-channel construction in SDM-EONs. Mixed super-channel oriented routing, spectrum and core assignment (MS-RSCA) algorithm is proposed in SDM-EONs considering inter-core crosstalk. Simulation results show that MS-RSCA can improve spectrum resource utilization and reduce blocking probability significantly compared with the baseline RSCA algorithms.
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an auxiliary graph based dynamic traffic grooming algorithm in Spatial Division multiplexing enabled elastic optical networks with multi core fibers
Optical Fiber Technology, 2017Co-Authors: Xiaosong Yu, Yongli Zhao, Rui Tian, Jiawei Zhang, Jie ZhangAbstract:Abstract A proper traffic grooming strategy in dynamic optical networks can improve the utilization of bandwidth resources. An auxiliary graph (AG) is designed to solve the traffic grooming problem under a dynamic traffic scenario in Spatial Division multiplexing enabled elastic optical networks (SDM-EON) with multi-core fibers. Five traffic grooming policies achieved by adjusting the edge weights of an AG are proposed and evaluated through simulation: maximal electrical grooming (MEG), maximal optical grooming (MOG), maximal SDM grooming (MSG), minimize virtual hops (MVH), and minimize physical hops (MPH). Numeric results show that each traffic grooming policy has its own features. Among different traffic grooming policies, an MPH policy can achieve the lowest bandwidth blocking ratio, MEG can save the most transponders, and MSG can obtain the fewest cores for each request.
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Multi-core virtual concatenation scheme considering inter-core crosstalk in Spatial Division multiplexing enabled elastic optical networks
China Communications, 2017Co-Authors: Yongli Zhao, Ruijie Zhu, Chunhui Wang, Jie ZhangAbstract:Spatial Division multiplexing enabled elastic optical networks (SDM-EONs) are the potential implementation form of future optical transport networks, because it can curve the physical limitation of achievable transmission capacity in single-mode fiber and single-core fiber. However, spectrum fragmentation issue becomes more serious in SDM-EONs compared with simple elastic optical networks (EONs) with single mode fiber or single core fiber. In this paper, multi-core virtual concatenation (MCVC) scheme is first proposed considering inter-core crosstalk to solve the spectrum fragmentation issue in SDM-EONs. Simulation results show that the proposed MCVC scheme can achieve better performance compared with the baseline scheme, i.e., single-core virtual concatenation (SCVC) scheme, in terms of blocking probability and spectrum utilization.
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crosstalk aware rcsa for Spatial Division multiplexing enabled elastic optical networks with multi core fibers
Chinese Optics Letters, 2016Co-Authors: Yongli Zhao, Hui Yang, Haoran Chen, Jie ZhangAbstract:In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment (CA-RCSA) algorithms for Spatial Division multiplexing enabled elastic optical networks (SDM-EONs) with multi-core fibers. First, the RCSA problem is modeled, and then a metric, i.e., CA spectrum compactness (CASC), is designed to measure the spectrum status in SDM-EONs. Based on CASC, we propose two CA-RCSA algorithms, the first-fit (FF) CASC algorithm and the random-fit (RF) CASC algorithm. Simulation results show that our proposed algorithms can achieve better performance than the baseline algorithm in terms of blocking probability and spectrum utilization, with FF-CASC providing the best performance.
Amj Ton Koonen - One of the best experts on this subject based on the ideXlab platform.
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Spatial Division multiplexing
Springer Series in Optical Sciences, 2017Co-Authors: Haoshuo Chen, Amj Ton KoonenAbstract:Spatial Division multiplexing (SDM) by employing few-mode fiber or multi-core fiber is expected to efficiently enhance the capacity of optical networks and overcome the anticipated ‘capacity crunch’ due to fast increasing capacity demand. This chapter first introduces the advantages and state-of-the-art of SDM. Second, different SDM technologies and key building blocks such as Spatial multiplexer, optical amplifier, wavelength selective switch, splicer, connector and digital signal processing block are thoroughly analyzed. Third, commercialized SDM-related components are summarized and discussed.
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ultra high density Spatial Division multiplexing with a few mode multicore fibre
Nature Photonics, 2014Co-Authors: R G H Van Uden, Amj Ton Koonen, Amezcua R Correa, Antonio E Lopez, F M Huijskens, Guifang Li, Axel Schulzgen, H De Waardt, C M OkonkwoAbstract:A few-mode, multicore fibre allows ultra-high-speed data transmission on a single wavelength of light.
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time domain multiplexed Spatial Division multiplexing receiver
Optics Express, 2014Co-Authors: Roy Van Uden, Haoshuo Chen, Chigo Okonkwo, Hugo De Waardt, Amj Ton KoonenAbstract:A novel time domain multiplexed (TDM) Spatial Division multiplexing (SDM) receiver which allows for the reception of >1 dual polarization mode with a single coherent receiver, and corresponding 4-port oscilloscope, is experimentally demonstrated. Received by two coherent receivers and respective 4-port oscilloscopes, a 3 mode transmission of 28GBaud QPSK, 8, 16, and 32QAM over 41.7km of few-mode fiber demonstrates the performance of the TDM-SDM receiver with respect to back-to-back. In addition, by using carrier phase estimation employing one digital phase locked loop per output, the frequency offset between the transmitter laser and local oscillator is shown to perform similar to previous work which employs 3 coherent receivers and 4-port oscilloscopes which are dedicated to the reception of each the three modes.
Haoshuo Chen - One of the best experts on this subject based on the ideXlab platform.
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Spatial Division multiplexing
Springer Series in Optical Sciences, 2017Co-Authors: Haoshuo Chen, Amj Ton KoonenAbstract:Spatial Division multiplexing (SDM) by employing few-mode fiber or multi-core fiber is expected to efficiently enhance the capacity of optical networks and overcome the anticipated ‘capacity crunch’ due to fast increasing capacity demand. This chapter first introduces the advantages and state-of-the-art of SDM. Second, different SDM technologies and key building blocks such as Spatial multiplexer, optical amplifier, wavelength selective switch, splicer, connector and digital signal processing block are thoroughly analyzed. Third, commercialized SDM-related components are summarized and discussed.
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transmission over 1050 km few mode fiber based on bidirectional distributed raman amplification
Journal of Lightwave Technology, 2016Co-Authors: Mina Esmaeelpour, Haoshuo Chen, Nicolas K Fontaine, Alan H. Gnauck, R.-j. Essiambre, Jean Toulouse, Robert LingleAbstract:We characterize the distributed Raman amplification in a 70-km three Spatial-mode few-mode fiber with different pump configurations and demonstrate bidirectional pumped Raman amplification and 1050 km combined wavelength-Division and Spatial-Division multiplexed transmission in the same fiber with a zero net gain fiber span.
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time domain multiplexed Spatial Division multiplexing receiver
Optics Express, 2014Co-Authors: Roy Van Uden, Haoshuo Chen, Chigo Okonkwo, Hugo De Waardt, Amj Ton KoonenAbstract:A novel time domain multiplexed (TDM) Spatial Division multiplexing (SDM) receiver which allows for the reception of >1 dual polarization mode with a single coherent receiver, and corresponding 4-port oscilloscope, is experimentally demonstrated. Received by two coherent receivers and respective 4-port oscilloscopes, a 3 mode transmission of 28GBaud QPSK, 8, 16, and 32QAM over 41.7km of few-mode fiber demonstrates the performance of the TDM-SDM receiver with respect to back-to-back. In addition, by using carrier phase estimation employing one digital phase locked loop per output, the frequency offset between the transmitter laser and local oscillator is shown to perform similar to previous work which employs 3 coherent receivers and 4-port oscilloscopes which are dedicated to the reception of each the three modes.
