The Experts below are selected from a list of 112455 Experts worldwide ranked by ideXlab platform
Norihiko Morinaga - One of the best experts on this subject based on the ideXlab platform.
-
symbol rate and Modulation Level controlled adaptive Modulation tdma tdd system for high bit rate wireless data transmission
IEEE Transactions on Vehicular Technology, 1998Co-Authors: T Ue, Norihiko Morinaga, Seiichi Sampei, Kiyoshi HamaguchiAbstract:This paper proposes a time-division multiple-access/time-division duplex (TDMA/TDD)-based symbol rate and Modulation Level-controlled adaptive Modulation system for high-bit-rate data transmission. The proposed system controls both the symbol rate and Modulation Level for the next transmission time slot according to the estimated carrier power to noise spectral density ratio (C/N/sub 0/) and delay spread for the time slot to achieve higher bit rate and higher transmission quality as well as higher delay-spread immunity. It is demonstrated by computer simulation and laboratory experiments that the proposed system can achieve a higher average bit rate with higher transmission quality in comparison with the fixed-rate quaternary phase-shift keying (QPSK) system and Modulation Level-controlled adaptive Modulation system in both flat Rayleigh and frequency-selective fading environments. The simulated and experimental results also show that the proposed adaptive Modulation techniques can be applied to 1-2-Mb/s indoor and outdoor microcellular systems with its delay spread of up to 250 ns and its terminal mobility of up to pedestrian speed without employing any special antifrequency-selective fading techniques, such as the adaptive equalizer and space diversity.
-
performance of Modulation Level controlled adaptive Modulation under limited transmission delay time for land mobile communications
Vehicular Technology Conference, 1995Co-Authors: Yukiyoshi Kamio, Seiichi Sampei, Hideichi Sasaoka, Norihiko MorinagaAbstract:The performance of an adaptive-Modulation/time division duplex (TDD) scheme to support constant-bit-rate services under transmission delay time constraint conditions is evaluated in this paper. According to the received signal conditions, the Modulation Levels or transmission modes are selected from transmission-off, QPSK, 16QAM, or 64QAM by using the reciprocity of the propagation path characteristics in the TDD systems. Moreover, the transmission delay time is limited to keep data transmission rate constant by the memory buffer. The received signal condition is estimated by using extrapolation of pilot symbol or estimated received signal distortion at the decision stage. The performance is evaluated by computer simulation in case of 32 ksymbol/s transmission and is compared with the performance of conventional trellis-coded (TCM) 32QAM. The results show that the proposed method improves the BER performance and delay spread immunity of a system transmitting data at a constant rate under multipath fading conditions and the performance is better than that of TCM-32QAM in Rayleigh fading conditions with small Doppler frequency.
-
symbol rate and Modulation Level controlled adaptive Modulation tdma tdd for personal communication systems
Vehicular Technology Conference, 1995Co-Authors: Seiichi Sampei, Norihiko MorinagaAbstract:This paper proposes a symbol rate and Modulation Level controlled adaptive Modulation/TDMA/TDD for future personal communication systems. To achieve wide dynamic range for the Modulation parameter control as well as to improve delay spread immunity, the proposed system controls both Modulation Level and symbol rate according to the channel conditions. Moreover, the proposed system also applies a novel channel condition monitor based on the instantaneous delay profile measurement for the Modulation parameter control. Computer simulation confirms that the proposed system can achieve higher bit rate transmission with higher quality in both flat Rayleigh and frequency selective fading environments.
-
square qam adaptive Modulation tdma tdd systems using Modulation Level estimation with walsh function
Electronics Letters, 1995Co-Authors: Shinya Otsuki, Seiichi Sampei, Norihiko MorinagaAbstract:The authors propose a square-QAM adaptive Modulation/time division multiple access/time division duplex (TDMA/TDD) system for land mobile communications to achieve high quality and high bit rate transmission in both flat and frequency selective fading environments. To further improve performance, a new Modulation Level estimation scheme using the Walsh function and maximum likelihood (MS) estimation is also proposed. Computer simulation confirms that the proposed system gives 8 dB better performance and four times larger delay spread immunity than that of conventional QPSK systems at BER = 10-3.
-
High bit rate transmission scheme with a multiLevel transmit power control for the OFDM based adaptive Modulation systems
IEEE VTS 53rd Vehicular Technology Conference Spring 2001. Proceedings (Cat. No.01CH37202), 2026Co-Authors: Tomoaki Yoshiki, Seiichi Sampei, Norihiko MorinagaAbstract:This paper proposes a multiLevel transmit power control (MTPC) for OFDM based adaptive Modulation systems (OFDM AMS) to achieve high bit rate transmission services without increasing the transmit power. In the proposed system the Modulation Level for each subcarrier is controlled according to the channel conditions. Moreover to further increase average bit rate, the proposed system employs a multiLevel transmit power control (MTPC) in which the Modulation Level and transmit power for each subcarrier is controlled to maximize transmitted bits per OFDM symbol while keeping its transmit power constant using a conventional transmit power control (TPC) technique. Computer simulation confirms that the proposed system is effective in achieving higher bit rate transmission without increasing its transmit power.
Seiichi Sampei - One of the best experts on this subject based on the ideXlab platform.
-
symbol rate and Modulation Level controlled adaptive Modulation tdma tdd system for high bit rate wireless data transmission
IEEE Transactions on Vehicular Technology, 1998Co-Authors: T Ue, Norihiko Morinaga, Seiichi Sampei, Kiyoshi HamaguchiAbstract:This paper proposes a time-division multiple-access/time-division duplex (TDMA/TDD)-based symbol rate and Modulation Level-controlled adaptive Modulation system for high-bit-rate data transmission. The proposed system controls both the symbol rate and Modulation Level for the next transmission time slot according to the estimated carrier power to noise spectral density ratio (C/N/sub 0/) and delay spread for the time slot to achieve higher bit rate and higher transmission quality as well as higher delay-spread immunity. It is demonstrated by computer simulation and laboratory experiments that the proposed system can achieve a higher average bit rate with higher transmission quality in comparison with the fixed-rate quaternary phase-shift keying (QPSK) system and Modulation Level-controlled adaptive Modulation system in both flat Rayleigh and frequency-selective fading environments. The simulated and experimental results also show that the proposed adaptive Modulation techniques can be applied to 1-2-Mb/s indoor and outdoor microcellular systems with its delay spread of up to 250 ns and its terminal mobility of up to pedestrian speed without employing any special antifrequency-selective fading techniques, such as the adaptive equalizer and space diversity.
-
Adaptive Modulation system with variable coding rate concatenated code for high quality multi-media communication systems
Proceedings of Vehicular Technology Conference - VTC, 1996Co-Authors: H Matsuoka, N. Morinaga, Seiichi Sampei, Yoko KamioAbstract:This paper proposes an adaptive Modulation system with a concatenated code (AMS-CC) for land mobile communications to achieve high quality, high bit rate transmission in Rayleigh fading environments. The proposed system adaptively controls the coding rate of the inner convolutional code, symbol rate, and Modulation Level according to the instantaneous fading channel conditions. The performances in Rayleigh fading environments are evaluated theoretically and by computer simulation. The results show that the proposed system can realize higher quality transmission without the degradation in average bit rate compared to conventional adaptive Modulation systems.
-
performance of Modulation Level controlled adaptive Modulation under limited transmission delay time for land mobile communications
Vehicular Technology Conference, 1995Co-Authors: Yukiyoshi Kamio, Seiichi Sampei, Hideichi Sasaoka, Norihiko MorinagaAbstract:The performance of an adaptive-Modulation/time division duplex (TDD) scheme to support constant-bit-rate services under transmission delay time constraint conditions is evaluated in this paper. According to the received signal conditions, the Modulation Levels or transmission modes are selected from transmission-off, QPSK, 16QAM, or 64QAM by using the reciprocity of the propagation path characteristics in the TDD systems. Moreover, the transmission delay time is limited to keep data transmission rate constant by the memory buffer. The received signal condition is estimated by using extrapolation of pilot symbol or estimated received signal distortion at the decision stage. The performance is evaluated by computer simulation in case of 32 ksymbol/s transmission and is compared with the performance of conventional trellis-coded (TCM) 32QAM. The results show that the proposed method improves the BER performance and delay spread immunity of a system transmitting data at a constant rate under multipath fading conditions and the performance is better than that of TCM-32QAM in Rayleigh fading conditions with small Doppler frequency.
-
symbol rate and Modulation Level controlled adaptive Modulation tdma tdd for personal communication systems
Vehicular Technology Conference, 1995Co-Authors: Seiichi Sampei, Norihiko MorinagaAbstract:This paper proposes a symbol rate and Modulation Level controlled adaptive Modulation/TDMA/TDD for future personal communication systems. To achieve wide dynamic range for the Modulation parameter control as well as to improve delay spread immunity, the proposed system controls both Modulation Level and symbol rate according to the channel conditions. Moreover, the proposed system also applies a novel channel condition monitor based on the instantaneous delay profile measurement for the Modulation parameter control. Computer simulation confirms that the proposed system can achieve higher bit rate transmission with higher quality in both flat Rayleigh and frequency selective fading environments.
-
square qam adaptive Modulation tdma tdd systems using Modulation Level estimation with walsh function
Electronics Letters, 1995Co-Authors: Shinya Otsuki, Seiichi Sampei, Norihiko MorinagaAbstract:The authors propose a square-QAM adaptive Modulation/time division multiple access/time division duplex (TDMA/TDD) system for land mobile communications to achieve high quality and high bit rate transmission in both flat and frequency selective fading environments. To further improve performance, a new Modulation Level estimation scheme using the Walsh function and maximum likelihood (MS) estimation is also proposed. Computer simulation confirms that the proposed system gives 8 dB better performance and four times larger delay spread immunity than that of conventional QPSK systems at BER = 10-3.
Jawad A Salehi - One of the best experts on this subject based on the ideXlab platform.
-
crosstalk aware resource allocation in survivable space division multiplexed elastic optical networks supporting hybrid dedicated and shared path protection
Journal of Lightwave Technology, 2020Co-Authors: Elham Ehsani Moghaddam, Hamzeh Beyranvand, Jawad A SalehiAbstract:In this paper, the problem of routing, Modulation Level, core, and spectrum assignment (RMCSA) in space-division-multiplexed elastic optical networks (SDM-EONs) is studied. We formulate this problem as a mixed-integer linear programming (MILP), in which dedicated and shared path protection schemes are supported in SDM-EONs with multi-core fibers (MCFs) and the inter-core crosstalk of MCFs is strictly modeled. Furthermore, an efficient heuristic algorithm is proposed to solve the RMCSA problem in a large scale scenario. Numerical results reveal that the formulated MILP leads to lower spectrum usage compared to the alternative methods. Moreover, the proposed heuristic algorithm performs close to the MILP formulation with lower computational run-time.
-
routing spectrum and Modulation Level assignment and scheduling in survivable elastic optical networks supporting multi class traffic
Journal of Lightwave Technology, 2018Co-Authors: Elham Ehsani Moghaddam, Hamzeh Beyranvand, Jawad A SalehiAbstract:As elastic optical networks (EONs) are expected to convey high bitrate connections, a failure in these networks causes vast data losses. Thus, addressing the problem of survivability in EONs is of great importance. In this paper, survivability of an EON with multiclass traffic is investigated, where each traffic type needs specific protection mechanism and scheduling strategy. In particular, a connection request may demand for dedicated path protection, shared backup path protection, or restoration mechanism. Besides, it can tolerate a pre-determined delay and be scheduled at future time slots, referred to as advance reservation, or must be served immediately without any delay, referred to as immediate reservation. Accordingly, we formulate an integer linear programming (ILP) to solve the routing, spectrum and Modulation Level assignment, and scheduling problems in both static and dynamic operation scenarios. In addition, to reduce the complexity of the ILP formulation in large scale networks, we propose a number of heuristic algorithms, in which two and three methods are considered for path selection and resource allocation, respectively. We evaluate the proposed heuristic algorithms in a small scale network by comparing their performance with the ILP formulation, then we apply them in a realistic large scale network. We compare all algorithms in terms of blocking probability, initial delay, and spectrum efficiency. Our results reveal that by using load-aware path selection and first-fit frequency-slice and time-slot assignment strategies the best compromise between blocking probability and initial delay is obtained.
-
crosstalk aware routing Modulation Level core and spectrum assignment and scheduling in sdm based elastic optical networks
International Symposium on Telecommunications, 2018Co-Authors: Elham Ehsani Moghaddam, Hamzeh Beyranvand, Jawad A SalehiAbstract:The transmission capacity of traditional single core fibers is reaching its upper bound. Space-division multiplexing (SDM) leveraging multi-core fibers is considered to be a promising solution for this problem. Elastic optical networks (EONs) with Multi-core fibers (MCF) are a kind of SDM-enabled EONs (SDM-EON) providing larger transmission capacity. However, the resource assignment in these networks becomes more complex due to inter-core crosstalk. Another important issue to be considered in future networks is the time domain behavior of incoming traffic which means considering Advance Reservation (AR) requests, in addition to regular Immediate Reservation (IR) requests. In this paper, the problem of routing, Modulation Level, core and spectrum assignment and scheduling is addressed in an SDM-EON with AR/IR traffic, in which inter-core crosstalk is modeled. This problem is formulated as a Mixed Integer Linear Programming (MILP) and a heuristic algorithm is proposed to solve it.
-
a quality of transmission aware dynamic routing and spectrum assignment scheme for future elastic optical networks
Journal of Lightwave Technology, 2013Co-Authors: Hamzeh Beyranvand, Jawad A SalehiAbstract:In this paper, we present a quality-of-transmission (QoT) aware dynamic routing, Modulation Level, and spectrum assignment scheme referred to as QoT-aware RSA. The proposed QoT-aware RSA has three stages: path computation with QoT-aware Modulation Level assignment, path selection, and spectrum assignment. Two schemes are presented in the path computation stage namely, modified Dijkstra and K-shortest-path algorithms. A closed-form expression is derived to model the fiber nonlinearity effects and the impairments of intermediate routers. This expression is utilized to estimate the network dependent QoT and the transmission reach of the Modulation Levels. We propose to select the best path in terms of optical signal-to-noise ratio (OSNR) metric. Furthermore, the traffic-balancing spectrum assignment method is utilized to serve the incoming request. The proposed scheme is evaluated using extensive numerical simulations based on both random and deterministic traffic models. The results of simulation reveal that the path selection and spectrum assignment methods can affect the average OSNR performance. Furthermore, the results show that the proposed path selection and spectrum assignment schemes outperform other existing alternatives in the literature.
Hamzeh Beyranvand - One of the best experts on this subject based on the ideXlab platform.
-
crosstalk aware resource allocation in survivable space division multiplexed elastic optical networks supporting hybrid dedicated and shared path protection
Journal of Lightwave Technology, 2020Co-Authors: Elham Ehsani Moghaddam, Hamzeh Beyranvand, Jawad A SalehiAbstract:In this paper, the problem of routing, Modulation Level, core, and spectrum assignment (RMCSA) in space-division-multiplexed elastic optical networks (SDM-EONs) is studied. We formulate this problem as a mixed-integer linear programming (MILP), in which dedicated and shared path protection schemes are supported in SDM-EONs with multi-core fibers (MCFs) and the inter-core crosstalk of MCFs is strictly modeled. Furthermore, an efficient heuristic algorithm is proposed to solve the RMCSA problem in a large scale scenario. Numerical results reveal that the formulated MILP leads to lower spectrum usage compared to the alternative methods. Moreover, the proposed heuristic algorithm performs close to the MILP formulation with lower computational run-time.
-
impairment aware manycast routing Modulation Level and spectrum assignment in elastic optical networks
IEEE\ OSA Journal of Optical Communications and Networking, 2019Co-Authors: Mehdi Habibi, Hamzeh BeyranvandAbstract:In this paper, we study the impairment-aware manycast routing, Modulation Level, and spectrum assignment problem in elastic optical networks. We formulate a mixed-integer linear program (MILP) that serves all the given manycast requests at once, referred to as a joint impairment-aware MILP. The formulated MILP can be used to jointly serve diverse traffic types, i.e., manycast, multicast, anycast, and unicast requests. In this formulation, nonlinear interference noise generated in fibers, the noise of optical amplifiers, the limitation of the maximum splitting degree of multicast-capable nodes (MCNs), and the power penalty of splitting the data flow into multiple branches at MCNs are considered. Furthermore, by modifying the joint MILP, two decomposed MILPs and corresponding heuristic algorithms are proposed to find a light-tree and assign Modulation Level and spectrum to the given requests, sequentially. We simulated the proposed heuristic algorithms and joint MILP (as a benchmark) and compared them with their distance-adaptive (DA) alternatives by considering a small-scale network. Our results reveal that our heuristic algorithms perform close to the joint MILP and have lower spectrum consumption than the DA alternatives. Furthermore, the performance of the heuristic algorithms is evaluated by considering a large-scale network. We observe that the number of occupied frequency slots and the average SNR of the network depend on the transmission power, and there is an optimum value for transmission power that maximizes the spectral efficiency. Moreover, the results show that the impairment-aware schemes outperform their DA alternatives in terms of spectrum consumption.
-
crosstalk aware routing Modulation Level core and spectrum assignment and scheduling in sdm based elastic optical networks
International Symposium on Telecommunications, 2018Co-Authors: Elham Ehsani Moghaddam, Hamzeh Beyranvand, Jawad A SalehiAbstract:The transmission capacity of traditional single core fibers is reaching its upper bound. Space-division multiplexing (SDM) leveraging multi-core fibers is considered to be a promising solution for this problem. Elastic optical networks (EONs) with Multi-core fibers (MCF) are a kind of SDM-enabled EONs (SDM-EON) providing larger transmission capacity. However, the resource assignment in these networks becomes more complex due to inter-core crosstalk. Another important issue to be considered in future networks is the time domain behavior of incoming traffic which means considering Advance Reservation (AR) requests, in addition to regular Immediate Reservation (IR) requests. In this paper, the problem of routing, Modulation Level, core and spectrum assignment and scheduling is addressed in an SDM-EON with AR/IR traffic, in which inter-core crosstalk is modeled. This problem is formulated as a Mixed Integer Linear Programming (MILP) and a heuristic algorithm is proposed to solve it.
-
routing spectrum and Modulation Level assignment and scheduling in survivable elastic optical networks supporting multi class traffic
Journal of Lightwave Technology, 2018Co-Authors: Elham Ehsani Moghaddam, Hamzeh Beyranvand, Jawad A SalehiAbstract:As elastic optical networks (EONs) are expected to convey high bitrate connections, a failure in these networks causes vast data losses. Thus, addressing the problem of survivability in EONs is of great importance. In this paper, survivability of an EON with multiclass traffic is investigated, where each traffic type needs specific protection mechanism and scheduling strategy. In particular, a connection request may demand for dedicated path protection, shared backup path protection, or restoration mechanism. Besides, it can tolerate a pre-determined delay and be scheduled at future time slots, referred to as advance reservation, or must be served immediately without any delay, referred to as immediate reservation. Accordingly, we formulate an integer linear programming (ILP) to solve the routing, spectrum and Modulation Level assignment, and scheduling problems in both static and dynamic operation scenarios. In addition, to reduce the complexity of the ILP formulation in large scale networks, we propose a number of heuristic algorithms, in which two and three methods are considered for path selection and resource allocation, respectively. We evaluate the proposed heuristic algorithms in a small scale network by comparing their performance with the ILP formulation, then we apply them in a realistic large scale network. We compare all algorithms in terms of blocking probability, initial delay, and spectrum efficiency. Our results reveal that by using load-aware path selection and first-fit frequency-slice and time-slot assignment strategies the best compromise between blocking probability and initial delay is obtained.
-
a quality of transmission aware dynamic routing and spectrum assignment scheme for future elastic optical networks
Journal of Lightwave Technology, 2013Co-Authors: Hamzeh Beyranvand, Jawad A SalehiAbstract:In this paper, we present a quality-of-transmission (QoT) aware dynamic routing, Modulation Level, and spectrum assignment scheme referred to as QoT-aware RSA. The proposed QoT-aware RSA has three stages: path computation with QoT-aware Modulation Level assignment, path selection, and spectrum assignment. Two schemes are presented in the path computation stage namely, modified Dijkstra and K-shortest-path algorithms. A closed-form expression is derived to model the fiber nonlinearity effects and the impairments of intermediate routers. This expression is utilized to estimate the network dependent QoT and the transmission reach of the Modulation Levels. We propose to select the best path in terms of optical signal-to-noise ratio (OSNR) metric. Furthermore, the traffic-balancing spectrum assignment method is utilized to serve the incoming request. The proposed scheme is evaluated using extensive numerical simulations based on both random and deterministic traffic models. The results of simulation reveal that the path selection and spectrum assignment methods can affect the average OSNR performance. Furthermore, the results show that the proposed path selection and spectrum assignment schemes outperform other existing alternatives in the literature.
Thierry Schuller - One of the best experts on this subject based on the ideXlab platform.
-
analysis of chemiluminescence density and heat release rate fluctuations in acoustically perturbed laminar premixed flames
Combustion and Flame, 2015Co-Authors: Daniel Durox, Franck Richecoeur, Thierry SchullerAbstract:Abstract Laser interferometric vibrometry (LIV) has recently been proposed as an alternative mean to obtain time-resolved density and heat release rate measurements at relatively low cost and experimental effort. This technique is sensitive to fluctuations of the refractive index of gases resulting from density and composition changes along the laser beam intersecting the reacting flow. It yields a line-of-sight integrated signal of the probed flow from which density and heat release rate disturbances may be inferred. The link between these signals with chemiluminescence is examined in the present study by first considering a theoretical analysis to determine the relationships between the LIV, density and heat release rate perturbation signals in a multi-species reactive mixture of gases. For air combustion systems interacting with sound waves, low frequency density perturbations in the flame zone, result mainly from heat release rate fluctuations below a certain frequency threshold. An experimental analysis is then conducted with confined conical laminar premixed flames submitted to harmonic flow Modulations. Measurements are presented for methane–air mixtures at different equivalence ratios 0.8 ≤ ϕ ≤ 1.2 and thermal powers. It is shown that fluctuations of the chemiluminescence signal examined in different wavelength bands, including the OH * , CH * or the entire visible emission bands, always capture the same dynamics. This indicates that heat release rate fluctuations can be deduced without specific filters for the laminar premixed methane–air flames investigated. It is then shown that heat release rate measurements deduced from LIV and chemiluminescence data match well. A proportional relation is found that does not depend on the measurement position, Modulation frequency and Modulation Level for fixed injection conditions. This linear relation slightly depends on the mean flow operating conditions partly due to the difficulty to interpret chemiluminescence emission for rich flames.
-
Reconstruction of heat release rate disturbances based on transmission of ultrasounds: Experiments and modeling for perturbed flames
Combustion and Flame, 2013Co-Authors: Franck Richecoeur, Thierry SchullerAbstract:Heat release rate fluctuations cause recurrent problems in many steady operating combustors. Direct measurements are difficult and these fluctuations are generally inferred from optical diagnostics. An alternative acoustic method was recently developed and is validated here in the case of unconfined laminar premixed flames submitted to harmonic flow Modulations. The technique relies on determining the transmission time of frequency-modulated ultrasounds propagating through the perturbed flow. The transmission of ultrasounds is altered by the perturbed interface between the burned gases and ambient air and by the perturbed flame front. A theoretical link between the dynamics of these two interfaces is derived for small low frequency perturbations. The predicted shapes taken by these interfaces are compared with two-color Schlieren images. This model is then used to determine the resulting heat release rate fluctuations and corresponding disturbances in the transmission time of ultrasounds. An analytical expression is derived for the transfer function between heat release rate and sound transmission time disturbances as a function of frequency when these conical flames are submitted to harmonic flow disturbances. Measurements made with this acoustic technique are compared to analytical predictions and to optical measurements exploiting the chemiluminescence emission from the flame. Effects of the forcing frequency and Modulation Level are examined. Results indicate a good match between predictions and measurements for the gain and phase of the transfer functions of the lean and stoichiometric unconfined flames investigated when the input Level is not too large. Issues and perspectives are then briefly discussed to extend this heat release rate measurement technique to practical configurations.