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The performance of linear filters degrade drastically when applied to mitigate intersymbol interference caused by channels with frequent nulls in their spectral characteristics like, e.g., time-dispersive radio channels. In such cases, the well-known decision feedback equalizer (DFE) is one possible nonlinear approach to improve the quality of the receiver. However, adapting the DFE filter coefficients...
We propose a parallel a posteriori probability (APP) decoding algorithm for increasing the decoding throughput of turbo codes. The parallel decoding algorithm divides a noisy codeword into multiple sub-blocks which are decoded in parallel. The authors in [1] proposed utilizing the forward and backward variables computed by neighbor sub-blocks in the previous iteration as the initial boundary conditions...
A general method to develop Tanner graphs from tail-biting convolutional codes (CC) is proposed. Recursive systematic convolutional (RSC) and non-RSC codes are considered consistently and it is shown that the elimination of redundant states leads to a graph with low complexity. In addition the graphical representation is extended to derive the condition for which the tail-biting termination is valid...
In this article we investigate low-density paritycheck (LDPC) codes for fast Rayleigh fading channels in the presence of channel estimation error. The analysis is carried out using the density evolution technique assuming a belief propagation (BP) decoder. After having derived the analytical framework for decoding analysis, we prove that there exists a simple approximated relationship, function of...
A block processing approach for decoding of convolutional codes is proposed. The approach is based on the fact that it is possible for Scarce-State-Transition decoding and syndrome decoding to determine the probability of a certain trellis state before the actual decoding happens. This allows the separation of the received sequence into independant blocks with known initial and final states, thus...
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...
In this paper, we present MRL-QRP, a multi-agent reinforcement learning based routing protocol with QoS support for wireless sensor networks. In MRL-QRP, sensor node cooperatively computes QoS routes using a distributed value function - distributed reinforcement learning algorithm (DVFDRL). Global optimization can be achieved by using locally observed network information and limited exchanging of...
Recent advancements in wireless communications and electronics have caused the emergence of a new type of networks called Wireless Sensor Networks (WSNs). WSNs have some unique features such as autonomy, low cost, tiny size, simple and fast deployment and high scalability, and many applications have been forecasted for them. In recent years, many WSN-based applications were proposed for Intelligent...
This paper addresses the trend in wireless sensor network applications of increasing node density and multi-hop communications that result into extremely challenging design constraints. SSAS, an adaptive hybrid localised sink-oriented Routing/MAC protocol is proposed. It offers a self-configuration scalable solution for large random sensor networks and attempts to alleviate multi-hop congestion problems...
Research on wireless sensor networks has recently received much attention as they offer an advantage of monitoring various kinds of environment by sensing physical phenomenon. Among various issues, energy consumption is one of the most important criteria for routing protocol in wireless sensor networks (WSNs). This paper introduces an energy efficient clustering algorithm for mobile sensor network...
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...
To extend the lifetime of wireless sensor networks a power-aware design of the communication units is required. This can be accomplished by employing power-controllable impulse radio ultra-wideband (IR-UWB) transceivers. In this paper, two distributed power control algorithms are suggested that are based on a variation of IR-UWB specific parameters. The iterative algorithms converge to the optimal...
Neighbor discovery is a fundamental procedure that needs to be carried out in every wireless sensor network in order to enable communication capabilities. If nodes are mobile or multiple channels are used in the network, the same algorithm may be needed to be carried out several times during the network lifetime, consuming precious energy. In this paper we propose a way for optimizing a neighbor discovery...
In this article we address the localization and tracking of multiple targets coincident in the same area. We propose a distributed method that enables us to simplify the signal processing and make the system more robust. Also we address a cluster of sensors, which are led by one of them (leader node). It is responsible to estimate the target??s location. To control the coincidence of multiple objectives...
Network survivability is one of the main design challenges in wireless sensor networks (WSN). Survivability is the ability of the network to provide essential services in the presence of attacks and/or failures, and recover full service in a timely manner. To the best knowledge of us, survivability for WSN has never been studied considering failure effects on network. We consider the network survivability...
Wireless sensor networks present a great potential in monitoring systems. A vast scope of applications can take advantage of WSNs and, mainly because of their own nature, the aggregation of WSN nodes into groups provides more potential solutions when compared with traditional monitoring systems. This paper introduces the issue of multicast messages and their impact on battery resources of WSNs. It...
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 2006, Wong et al. proposed a dynamic user authentication scheme for WSNs that allows legitimate users to query and collect sensor readings from sensor nodes of the network. They presented analysis to show that their scheme is secure and efficient. Later, in 2007, Tseng et al. pointed out several weaknesses in Wong et al.??s scheme and proposed an improved scheme to overcome the weaknesses. However,...
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...
Positioning systems are one of the multiple applications of the wireless sensor networks. These networks are very adequate in environments where other positioning technologies, as satellite systems, do not work. Bluetooth is a promising technology, since it is present in any kind of portable devices. By using the received signal strength indicator (RSSI) it is possible to make an estimation of the...
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