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Inter-cell Interference (ICI) in the uplink of modern cellular communication systems with high frequency reuse is hard to predict, as fast scheduling and link adaptation lead to a high interference fluctuation. This fluctuation poses a big challenge for link adaptation algorithms that need an accurate SINR estimate to assign suitable modulation and coding schemes for transmission. To enable ICI prediction...
This paper studies the capacity performance of coordinated multi-point (CoMP) downlink transmissions based on limited feedback. We consider both path loss effects and channel imperfections including feedback delay and quantization error. Closed-form expressions are derived to characterize ergodic achievable rates for joint processing (JP) and coordinated beamforming (CBF) techniques, respectively...
Coordinated multi-point (CoMP) transmission is considered as an efficient technique to improve cell-edge performance as well as system spectrum efficiency. In CoMP-enabled systems, a cluster of coordinated base stations (BSs) are typically assumed to be connected to a control unit (CU) via backhaul links, and the provided performance gain relies heavily on the quality of the channel state information...
Resource allocation is a critically important issue for cognitive networks, because it needs to not only meet the quality-of-service (QoS) requirements for the secondary users (SU), but also protect the QoS of primary users (PU) from degradation. In this paper, we develop the optimal power allocation scheme for the cognitive network, which can satisfy the QoS requirements of SUs and PUs simultaneously...
This paper studies a spectrum sharing cognitive radio (CR) network coexisting with a primary network. In particular, the channel state information (CSI) between the secondary transmitter (STx) and the primary receiver (PRx) is assumed to be outdated due to channel feedback latency. We assume that the secondary user (SU) shall satisfy a given delay quality-of-service (QoS) constraint as well as the...
In this paper, we will illustrate a practice of pipeline process to maximize the parallelization of all possible interference-free relays in the broadcasting of wireless sensor networks (WSNs), in order to optimize the end-to-end delay performance in both the (synchronous) round-based systems and the (asynchronous) duty cycle systems. Broadcasting is one of the fundamental communications in WSNs....
In this paper we validate and extend through simulations the trends revealed by the analytical results of our prior work concerning the throughput-delay trade-off that can be achieved by forwarding schemes exploiting path diversity and different degrees of redundancy focusing on the case of hop-by-hop retransmissions at the link-layer. The simulation environment is based on 802.11 Physical and Mac...
Noncoherent UWB receivers promise low power consumption and low processing complexity but their peak data rate is limited by the delay spread of the multipath radio channel. A recently proposed multichannel autocorrelation receiver (AcR) can break this rate limit due to its multicarrier signal demodulation capability. In this paper, the hardware implementation of this receiver architecture is addressed...
Multi-core virtualization platform is an essential basement of modern computing environment including server consolidation and cloud computing. However hidden contention for physical resources between different workloads always causes serious performance interference and thus reduces system performance and efficiency. In order to address this issue, we exploit the possibility of scheduling virtual...
Primary results of fundamental research in the field of radar theory are presented. The novelty of the research consists in the following: within the scope of energy conservation law and Bayes statistical decision theory a new approach to the process of target radar signals detection on the basis of energy criterion is considered. A condition for radio-signals optimal energy detection against a background...
In mobile cognitive radio networks, the expected delay for a packet to be delivered to its destination via a singlehop communication (without relaying) is a fundamental metric that can provide a guidance to multi-hop routing protocol design and route planning. In this paper, we characterize the impact of PU activities, spectrum availabilities, channel bandwidth, MAC access, SU mobilities, and interference,...
Wireless mesh networks (WMNs) have been increasingly used to carry multimedia traffic with flow requirements. The performance of multi-radio multi-channel (MRMC) WMNs largely depends on the routing and channel assignment. Because routing and channel decisions are coupled, they need to be jointly optimized to achieve the best performance. This is the so-called routing and channel assignment (RCA) problem,...
Space Wire is a standard of on-board networks for satellites promoted by the ESA. As the ESA plans to use Space Wire as the sole network for both critical and non-critical traffics, network designers need tools to check that all the critical messages meet their deadlines. We previously proposed two such tools to compute an upper-bound on the worst-case end-to-end delay of a packet traversing a Space...
Shared resource access interference, particularly memory and system bus, is a big challenge in designing predictable real-time systems because its worst case behavior can significantly differ. In this paper, we propose a software based memory throttling mechanism to explicitly control the memory interference. We developed analytic solutions to compute proper throttling parameters that satisfy schedulability...
Some analyses and researches are done about networked control systems (NCS) those are based on the new Smith predictor and internal model control (IMC) from the system structures in this paper. The research and simulation results show that the choice of strategy of the new Smith predictor is more flexible than internal model control, but the adjusting parameter of the internal model control is relatively...
With the development of wireless sensor networks in industry, it is difficult for MAC protocol with single channel to meet the demands of combating interference, high reliability and low delay. The multichannel MAC protocol is a promising approach to meet these challenges. IEEE 802.15.4 standard is the foundation of ZigBee, WirelessHART and ISA100. This article proposes a multi-channel MAC protocol...
This study investigates a Wi-Fi-based Wireless Networked Control System. This system is first modified in order to enhance resistance to interference. Then, it is subjected to different types of interference. The system consists of a workcell containing 30 sensors, 30 actuators and 1 controller. All forms of interference modeled focus on the operating frequency band used by the control nodes. All...
Platooning with IVC-enabled autonomous vehicles may enable a significant increase in lane capacity, if performed with constant spacing policies. However, to be effective, such system is very demanding with respect to communication performance and reliability. Dedicated short range communications (DSRC) is the prominent intervehicle communication (IVC) technology. However, its reliability rises concerns...
In this contribution, we introduce an interference alignment scheme that allows the coexistence of an orthogonal frequency division multiplexing (OFDM) macro-cell and a cognitive small-cell, deployed in a two-tiered structure and transmitting over the same bandwidth. We derive the optimal linear strategy for the single antenna secondary base station, maximizing the spectral efficiency of the opportunistic...
Routing for Delay Tolerant Networks (DTNs) are challengeable for the continuously varied network environment. Most of existing DTN routing algorithms mainly focus on metrics such as delay, hop count and bandwidth, etc. Green communication is a new focus with the goal of saving energy by optimizing network performance and ultimately protecting the natural climate. In this paper, we present an Energy-efficient...
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