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The fifth-generation (5G) wireless communication systems envision the deployment of massive multiple-input multiple-output (MIMO) technology for enhanced network coverage and capacity. With frequency division duplex (FDD) being the prominent mode of operation, addressing the challenges for massive MIMO systems in FDD is extremely important. One such challenge is the downlink channel estimation, which...
In this paper, we consider an optimal estimation problem in the sense of least mean square error for linear discrete-time systems with multiple state delays in the measurement output. Since computation complexity is high for augmentation approach, a lot of researches have been dedicated to finding alternative ways for the optimal estimation design. In existing studies, two dimensional Riccati iteration...
This paper deals with the problem of reachable set estimation for singular systems with time-varying delays. Based on the Lyapunov-Krasovskii functional approach and the reciprocally convex inequality, sufficient delay-dependent conditions are obtained in terms of linear matrix inequalities (LMIs) for the existence of an intersection of ellipsoids, which contains the considered system states under...
The optical network of the future will have ~3 orders of magnitude increase in data rates, mostly due to large transactions. These elephant flows need fast scheduling of network resources and agile network adaptations for congestion control, load balancing and reconfiguration to cope with huge traffic transients and reconstitution for network resilience. This paper move beyond SDN as well as “orchestration,”...
In order to describe the highly scattered property of millimeter wave (mmWave) multiple-input multiple-output (MIMO) channels, the existing high resolution frequency domain space-alternating generalized expectation-maximization (FD-SAGE) algorithm is studied and extended to three-dimentional (3D) MIMO case by including the estimation of elevation angles. The signal model and estimation procedure are...
Channel estimation is one of the most important parts in current mobile communication systems. Among the huge contributions in channel estimation studies, the discrete Fourier transform (DFT)-based channel estimation has attracted lots of interests since it can not only be easily implemented but also have acceptable performance in practical systems. In this paper, we propose an improved DFT-based...
An important concern for current IaaS cloud providers is to be falsely accused by cloud users for the response delays of their applications running on the cloud. Since cloud computing brings an additional virtualization layer between guest-OS and hardware resources, the relationship between the performance of an application and its resource consumption becomes obscure. Only monitoring resource consumption...
A minimum mean square error estimation (MMSE) using a virtual pilot channel estimation scheme was proposed by our researchers for improving the error performance of the IEEE 802.11p. However, compared to the STA channel estimation scheme, the MMSE scheme cannot provide an acceptable error performance in a low SNR region. To alleviate this, we propose an adaptive channel estimation scheme, which selectively...
We consider a real-time status update system consisting of a source-destination network. A stochastic process is observed at the source, and samples, so called status updates, are extracted at random time instances, and delivered to the destination. In this paper, we expand the concept of information ageing by introducing the Cost of Update Delay (CoUD) metric to characterize the cost of having stale...
Formation flying missions require the knowledge of the relative positions of the satellites for formation, maintenance and scientific purposes. In Low Earth Orbit, this task is typically performed by GPS-based navigation filters. However, the final accuracy, especially over long baselines, is strongly affected by the capability of correctly estimating the ionospheric delays. In this paper the performance...
In this paper, we consider a problem of sampling a Wiener process, with samples forwarded to a remote estimator via a channel that consists of a queue with random delay. The estimator reconstructs a real-time estimate of the signal from causally received samples. Motivated by recent research on age-of-information, we study the optimal sampling strategy that minimizes the mean square estimation error...
Effective mutual interference suppression methods are proposed for terrestrial ultra-wideband systems of mediumwave band. Navigation signals modulated with data provide higher accuracy, satellite and terrestrial systems integration. Such long range systems characterized by powerful mutual interferences.
We prove convergence of the projected gradient algorithm with inexact projections when applied to linear inverse problems with constraint sets that are unions of subspaces. Such an algorithm is useful for joint angle and delay estimation in MIMO radar, where classical estimators for angle estimation can be integrated into compressive sensing methods for range estimation.
This paper presents a data-driven model to estimate the traversal speed of public transport on urban arterials under non-recurring congestion. We group unidirectional links of an arterial and use the concept of Macroscopic Fundamental Diagram to achieve a smooth speed-density relationship along the arterial. The methodology comprises two main steps: first, developing the model and estimating fit parameters...
With the prevalence of the online to offline (O2O) commerce, the short-distance instant logistics service becomes increasingly popular in China, which is a new logistics model emerged recently and provides timely logistics for O2O local life service. Being different from traditional logistics, extra waiting time generates when order's pick-up location arrival time is early than its pick-up ready time,...
We propose a new method for optimizing fixed-time traffic control plans and timings at isolated intersections by minimizing the Conditional Value-at-Risk (CVaR) of the intersection's average delay over an extended peak period. The optimization algorithm was implemented in Matlab using a scatter search algorithm to minimize the CVaR of the average delay which is based on the HCM formula for multiple...
Doubly selective channels or time-varying multipath channels occur when communication systems are expected to work in a highly mobile environment. The estimation and the subsequent equalization of such channels is a non-trivial task. Thus, a channel estimation scheme that is robust, precise and works with a complexity that is applicable for consumer applications is vital to overcome the effects of...
Delay Tolerant Networks (DTN) are characterized by a lack of end-to-end connectivity. As such, messages (called bundles) can be stored in buffers for a long time. Network congestion can result in poor delivery rates, as bundles are dropped before having a chance of reaching their destination. Some routing protocols, such as the Probabilistic Routing Protocol using History of Encounters and Transitivity...
Industrial facilities show an increasing need for continuous measurement and monitoring a large number of process variables due to strict product quality requirements, environmental laws and for advanced process control application. On-line analyzers typically suffer from long measurement delays not desirable in continuous control. Suitable alternative are soft sensors and inferential control. In...
System-level timing inconsistency and wireless communication delays are the main uncertainties of existing synchronization mechanisms for wireless sensor networks. Existing solutions mainly rely on timestamp exchanges to estimate clock offset and skew, which results in frequent synchronization, high overhead, and high energy consumption to maintain a well-synchronized network. This paper introduces...
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