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In this paper we revisit the carrier frequency offset (CFO) estimation and removal for broadband orthogonal frequency division multiplexing (OFDM) systems. We propose an algorithm that explores the time-domain (TD) properties of transmitted symbols carrying pilots and data. A careful examination of the components that constitute the TD received symbols leads to the definition of a simple, yet effective,...
Cooperative communication based on cooperative diversity allows a collection of radio terminals to relay signals for each other in wireless fading channels. In wireless ad hoc networks, nodes communicate with each other using multihop routed transmission and thus hop-by-hop cooperative diversity can be effectively exploited. This paper proposes two cooperation models of per-link cooperation (PLC)...
The contribution describes a basic structure of the low rate wireless encoder and its application in domain of the video signal transmission. Also, the experimental results with real video sequences encoded by a three-dimensional discrete cosine transform coder will be presented. Finally, compress ratio and picture quality values will be published as well.
RSSI (received signal strength indicator)-based localization is advantageous in terms of transceiver hardware complexity, because almost all current wireless standards have the functionality in their protocols. In a localization area, a ??design?? problem to determine the placement of anchor nodes satisfying a required localization accuracy has never been addressed, although the accuracy of RSSI method...
This paper investigates the problem of optimal assignment of wireless interfaces for service delivery in the context of a heterogeneous wireless access system. We formulate service requests initiated by the applications running on the mobile device as a multiobjective optimization (MOO) problem: optimal mapping of application requirements to wireless interface while minimizing the monetary cost and...
In this paper we present a method for the quasi-reliable transfer of Digital Cinema (DC) content over packet-lossy IP networks, such as wireless networks. By employing the MXF (Material eXchange Format) encapsulation, reliable transmission of MXF keys backup, and compressed frames Forward Error Correction (FEC), we show that visual artifacts due to packet losses are virtually cancelled, and decoder...
The present paper investigates call admission control (CAC) over multiservice wireless - broadband over power line (BPL) networks. The CAC problem is examined not only as a decision process but, also, as a channel reallocation and QoS renegotiation process. A fast and effective CAC algorithm for BPL networks is proposed providing high network utilization, low blocking rate (BR) and fairness between...
Generative models hold the promise of reducing the computational load and cost caused by directly simulating a real system. They are vital to the design and performance evaluation of error control schemes and high layer wireless communication protocols. Therefore, designing an efficient and accurate generative model is highly desirable. Moreover, the errors encountered in digital wireless channels...
The IP tunneling mechanisms have important applications in network solutions and are widely used in numerous contexts such as security (VPN), IPv4 to IPv6 transition, and mobility support (MobileIP and NEMO). However, these tunneling mechanisms induce a large overhead resulting from adding several protocol headers in each packet. Moreover, this header overhead could be found on wireless links which...
The next generation of wireless communications systems will likely incorporate MIMO techniques in order to provide higher data rate multimedia services. Moreover, the transmission control protocol (TCP) is generally employed at the transport layer for reliable data communication. Thus, the optimization of TCP/RLP performance over MIMO systems is currently an important research area. In this paper,...
The system capacity of a cellular wireless system consisting of a large number of fixed location base stations (BSs) and random location mobile stations (MSs) is studied. Assuming that the BSs in a multi-cell system are connected to a centralized controller which has access to channel state information (CSI), it is possible to optimize transmissions such that capacity is maximized. This paper discusses...
In this paper, we examine the spatial diversity of cooperative communications for image transmission without deploying multiple antennas at the transmitter. We propose a novel region of interest (ROI)-based scheme for image transmission over wireless cooperative/relay fading channels. By having the relay terminal assist the direct communications, we can increase the resilience for ROI against the...
We have recently introduced in the literature a new access control protocol for next generation wireless cellular networks, which showed superior performance in comparison to other (TDMA and WCDMA-based) protocols when integrating various types of multimedia traffic. In this Extended Abstract, we show that the use of stack protocols to resolve contention among contending multimedia terminals is not...
In many cases, a mobile user has the option of connecting to one of several 802.11 access point (APs). We consider the case when users multihome, i.e., split their traffic among all available APs, based on the long-term channel characteristics such as burstiness and packet error rate. This type of operation requires a new multi-access control (MAC) protocol, where the user has to decide to which AP...
The method proposed here gathers data in high- density wireless sensor networks in real-time. It determines network topology by hierarchical clustering to avoid radio collision, which enables us to gather data with minimum data latency from numerous high-density sensor nodes. The analysis of our proposed tree-based data gathering protocol and real experiments using 39 real sensor nodes show that the...
Wireless video sensor networks (WVSNs) bring a new set of design challenges due to their specific application requirements in terms of latency, bit rate, and power consumption. In this paper, we propose an application layer power-congestion-distortion (P-C-D) optimized multi-path transmission scheduling algorithm. The algorithm utilizes existing techniques and protocols on the various layers and is...
Cross-layer design for wireless networks aims at optimizing system-wide performance measures by exploiting dependencies between different network layers. In this paper, an opportunistic power assignment algorithms for IR-UWB sensor networks is presented that is especially designed for distributed signal detection under resource constraints. Specifically, the objective is to minimize the global probability...
In this paper, we investigate the performance of using high altitude platforms (HAPs) for low power wireless sensor network (WSN) applications. In our study, HAPs are employed to replace the sink usually deployed on the ground and collect data from sensor nodes. Two scenarios of employing the HAP as the sink in the WSN are established. Multiple sensor nodes are organized in an ad-hoc manner or in...
In this paper, the performance of the wireless-signal map-matching method under a code division multiple access network environment is demonstrated. The wireless-signal map-matching method is the key step to implement the recently introduced wireless location technology referred to as the localization exploring network measurement occurrences. The wireless-signal map-matching method is applied to...
Indoor location tracking is a function best suited to wireless LAN devices. This generally precludes it from home use in isolated rural areas, where WLAN is a rare commodity. We propose an affordable localisation system which can be implemented using a variety of Bluetooth enabled mobile phones. This permits the incorporation of cellular network signal measurements as well as Bluetooth link measurements...
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