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We consider channel estimation in amplify-and forward (AF) wireless relay networks (WRNs) when coherent distributed space-time coding is performed at relays. We perform minimum mean-square-error detection at the destination when partial channel state information is available. For channel estimation, we propose to use a semi-blind method based on the expectation maximization (EM) algorithm. Using an...
In recent years, wireless sensor networks (WSN) have received a lot of attention and several cryptographic protocols have been proposed to protect WSN. However, it still opens that how to balance authenticity and transmission. For authenticating the message from a sensor, the message is appended a Message Authentication Code (MAC) authenticating it. These MACs may result in large amount of transmission,...
Wireless Sensor Networks are gaining importance in diverse applications. The sensor nodes are battery operated and hence energy aware architecture is considered for increasing the lifetime of the sensor network. In this paper clustering algorithm based on spatial correlation is implemented to improve the performance of Distributed Source Coding (DSC) Algorithm. Results show that the proposed clustering...
Network coding scheme improves throughput and reliability in a Wireless Sensor Network. A straight forward broadcasting by flooding in a wireless sensor network is very costly and reduce the network coding benefit. The packet loss probability increases due to contention and collision which is referred as broadcast storm problem. In this paper, we have proposed a Network Coding based Probabilistic...
Wireless sensor networks demand the implementation of energy-aware transmission protocols. Recently, cooperative protocols have been suggested for use in sensor networks since they typically require less transmit power than the direct transmission for the same error probability. For sensor networks with short range transmissions, however, the energy consumed in receiving transmissions from cooperative...
In this paper, we study the problem of random field estimation with wireless sensor networks. To that aim, we adopt two encoding strategies, namely Compress-and-Estimate (CE) and Quantize-and-Estimate (QE), which operate with and without side information at the decoder, respectively. We focus our attention on delay-tolerant (DT) networks where sensors have the flexibility to encode and transmit a...
Wireless sensor networks (WSNs) require simple and facile error control schemes because of the low complexity and high energy efficiency request of sensor nodes. In this paper, we discuss ARQ, FEC, and Chase combing hybrid ARQ (HARQ) schemes using energy efficiency analysis on different communication distances and link layer frame lengths. We proposed a high energy efficiency adaptive error control...
This paper considers a large-scale wireless sensor network where sensor readings are occasionally collected by a mobile sink, and sensor nodes are responsible for temporarily storing their own readings in an energy-efficient and storage-efficient way. Existing data persistence schemes based on erasure codes do not utilize the correlation between sensor data, and their decoding ratio is always larger...
Many application scenarios have been revealed with Sensornets. An Error Correcting Code (ECC) will be advantageous to communications in these applications. With the different expecting on efficiency, security, usability, etc, different codes have been constructed for various purposes. The methods based on algebra theory can work well for constructing simple and usability codes. The theory of algebraic...
Abstract-In this work, we describe preliminary results re lated to an ultra-low power vision sensor, embedding contrast extraction and output data compression. The sensor performs less than 30 μW at 3.3 V and 30 frame/s, combining data compression together with event detection capabilities and efficient sensor interface. This makes the presented sensor to be suitable for energy-autonomous...
Recently, there has been an increasing interest in applying wireless sensor networks for health status monitoring both on and within the human body. Low power consumption is crucial in such applications, especially for implanted devices. UWB transmission is one way of making low power transmission possible. A further reduction in power consumption can be achieved through efficient signal compression...
The following papers are dealt with: decoding order in non-ideal DSL multiple access channels; co-channel interference; narrowband interference suppression in UWB; coded modulations for block fading channels; DVB-T2; ASIP decoder for combined binary and non-binary LDPC codes; OFDM systems; mobile spectrum occupancy monitoring network; adaptive array antennas in ad hoc networks; MAC protocols and;...
In this paper, we propose Opportunistic Carrier Prediction (OCP) that jointly addresses exposed terminal and hidden terminal problems in wireless networks. OCP is based on the rationale that past interference information can be a good indicator for the outcome of future packet delivery. Each OCP sender maintains a summary of past interference information and opportunistically accesses the channel...
Power efficiency is a key issue in wireless sensor networks due to limited power supply. Buffer management is also crucially important in the scenario where the incoming traffic is higher than the output link capacity of the network since a buffer overflow causes power waste and information loss if a packet is dropped. There are many available buffer management schemes for traditional wireless networks...
Wireless Sensor Networks (WSNs) consist of a set of small devices with limited energy resources, reduced processing capabilities and a radio frequency communication unit with limited transmission power. Transmission over the wireless channels is prone to noise and interference which causes the reception of erroneous packets at the receiving node. Automatic Repeat Request (ARQ) techniques are usually...
Concurrent cooperative transmission (CCT) is a cooperative transmission (CT) technique where multiple radios transmit diversity versions of the same message at the same time. Through array gain and diversity gain, CCT achieves a signal-to-noise (SNR) advantage, which can be used for better link reliability and transmission range extension. CCT range extension can enable broadcasting with fewer hops,...
In this work, we focus on the use of network coding in a wireless sensor network where data is already encoded at the source node with fountain codes, in particular LT or Raptor codes. These codes have a specific degree distribution to follow in order to obtain an efficient decoding process. However, adding a layer of network coding on such packets triggers a distorsion of the degree distribution...
Distributed video coding is a new paradigm for video compression based on the Slepian-Wolf and Wyner-Ziv theorems. Wyner-Ziv video coding, a lossy compression with receiver side information, enables low-complexity video encoding at the expense of a complex decoder. Most of the existing distributed video coding techniques require a feedback channel to determine the number of parity bits for decoding...
Energy efficient reliable communication over unpredictable wireless medium is a major challenge for resource constrained wireless sensor nodes employed in process/environment control application. In this paper, we suggest the soft decision decoding (SDD) based advanced Forward Error Correction (FEC) scheme for low power distributed sensor nodes. The proposed BCH (Bose-Chaudhuri-Hocquenghem) based...
Packet-combining schemes are an attractive improvement to ARQ schemes, since they allow receivers to keep the good parts of an otherwise erroneous packet and use these with good parts from subsequent packets to allow for quicker decoding. In the previous paper a memory-efficient hard-decision packet combining scheme has been described and analysed, which relies on intermediate checksums spread into...
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