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This paper investigates a beamforming control method in base station (BS) cooperative multiuser multiple-input multiple-output (MIMO) transmission assuming a block-diagonalized unitary beamforming matrix. More specifically, we comprehensively compare open-loop type random (opportunistic) beamforming control to codebook-based closed-loop type beamforming control. The proportional fair (PF)-based scheduling...
Dual sequence current control is the key technique for grid-connected voltage source converter to ensure the performance or fulfill grid requirement under unbalanced grid voltage conditions. In this paper, after reviewing and analyzing the existing dual sequence current controller (DSCC), a simple DSCC is proposed based on double synchronous reference frame (DSRF) without the need of current sequence...
Survivability is a key attribute to measure large-scale network security and has become a hot research issue. Large-scale network is a complex system, which has the typical survivability characteristics of complex system. The current network survivability studies usually aim for a specific aspect of network. In this paper, we attempt to study the survivability of large-scale network based on the characteristics...
In this paper, we consider one of the main disadvantages of Ergodic Interference Alignment, i.e., delay. We propose two methods to solve the open problem of finding the best choice of user sets in order to minimize the delay. With these methods we are able to find the best JAP-B scheme which aims to trade off rate for delay in Ergodic Interference Alignment. First, we provide the solution based on...
The widely used broadband wireless technology enables a novel application of providing high-quality communications between vehicles and traffic control centers, which is collectively referred to as vehicle-to-ground communications. Channel modeling is in rapidly increasing demand to design and optimize the vehicle-to-ground communication systems. And practical channel models are only available when...
Adaptive equalization is a widely used method of mitigating the effects of multipath propagation and Doppler spreading in underwater acoustic communication channels. This paper examines some specifics associated with the design of a multi-channel equalizer for time-varying underwater acoustic channels. More specifically, we study how the number of sensors and separation between them impact the equalization...
Dynamic Time-division duplex (TDD) can provide efficient and flexible splitting of the common wireless cellular resources between uplink (UL) and downlink (DL) users. In this paper, the UL/DL optimization problem is formulated as a noncooperative game among the small cell base stations (SCBSs) in which each base station aims at minimizing its total UL and DL flow delays. To solve this game, a self-organizing...
In this paper, the problem of content-aware user clustering and content caching in wireless small cell networks is studied. In particular, a service delay minimization problem is formulated, aiming at optimally caching contents at the small cell base stations (SCBSs). To solve the optimization problem, we decouple it into two interrelated subproblems. First, a clustering algorithm is proposed grouping...
In mobile slow fading scenarios, channel state information (CSI) is required at the transmitter to adapt the data transmission strategy to the current channel state. In this regard, precoding in multiuser-multiple-input-multiple-output (MU-MIMO) downlink systems is a prominent example. In frequency division duplex, channel observations are quantized and fed back via the uplink, protected by an error...
Quality of service (QoS) requirements are usually different from user to user in a multiaccess system, and it is necessary to take the different requirements into account when allocating the shared resources of the system. In this paper, we consider one QoS criterion-average packet delay in a multiaccess system, and we combine information theory with queueing theory in an attempt to analyze whether...
Fused multiply-add (FMA) units can reduce latency and increase energy efficiency in arithmetic operations. A modified architecture of a multiply-accumulation chained unit (MFMA) is described in this paper. The add/sub pipelined datapath of a traditional fused multiply-add unit is modified to save hardware resources, conserve energy and reduce latency in DSP applications. The proposed datapath for...
This paper describes characteristics of direct and scattered waves that are extracted from measurement channel data obtained using a 3.35 GHz vector channel sounder in an indoor environment. Each ray of the scattered waves is designated a number in order of the received level. The relationship between the ray number and the characteristics of each ray such as the received level, delay time, and azimuth...
This paper considers a new system structure, which does not require current sensors for control and is optimized for medium- and small-power drives with strict requirements on precision. The main difference between traditional vector control and the proposed structure is a direct axis current compensator (DACC). DACC simplifies the control algorithms and cheapens the control hardware, in particular,...
Finite control set model predictive control requires a considerable computational burden and it is inevitable to have a time delay between the measurement and the actuation instants in an electric drive based on this control strategy. In this work, it is proposed a new method to compensate the calculation delays in an induction motor drive using predictive control. This new compensation method takes...
Underwater wireless sensor networks (UWSNs) have become the seat of researchers' attention recently due to their proficiency to explore underwater areas and design different applications for marine discovery and oceanic surveillance. One of the main objectives of each deployed underwater network is discovering the optimized path over sensor nodes to transmit the monitored data to onshore station....
Timed marked graphs (TMGs), a special class of Petri nets, are used to model and analyze cyclic manufacturing systems. Weighted marked graphs (WMGs) are convenient to model systems with bulk services and arrivals. It is possible to apply analytical techniques for the marking optimization problem of such systems. The problem consists in minimizing the cost associated with an initial marking that ensures...
In this paper we explore a novel feature for the segmentation of heart sounds: the entropy gradient. We are motivated by the fact that auscultations in real environments are highly contaminated by noise and results reinforce our suspicions that the entropy gradient is not only robust to such noise but maintains a high sensitivity to the S1 and S2 components of the signal. Our whole approach consists...
Teleoperation systems developed in joint-space or task-space without taking into account parameter uncertainties impede the application of such framework on automation and manufacturing system. In this paper, a passivity-based control framework is proposed to accomplish teleoperation in the presence of unknown parameters and communication delays. First, we demonstrate that based on the addressed adaptive...
Signal processing requires high performance digital signal processors(DSP) and hardware accelerators. Real and complex multiply-accumulate(MAC) units are the most critical computation units in the DSPs and accelerators, which greatly impact the performance, power and chip area of the signal processing system. A fixed-point Single-Instruction-Multiple-Data(SIMD)/vector MAC architecture is presented...
In this paper, a output regulation problem with time-varying sampling interval is investigated. An input delay approach is used to convert a sampled data feedback system into a continuous time-delay systems. Two sufficient conditions for the output regulation problem are presented in terms of LMIs. Finally, a numerical simulation example is given to demonstrate the effectiveness of the developed analytic...
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