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In this paper, we present a review on the recent progress of real-time experiments for optical OFDM with detailed description on real-time O-OFDM transmission system and digital signal processing algorithms.
A 90nm, IR UWB, duty-cycled transceiver chipset, for operation from 7 to 9.8GHz and compliant to the IEEE802.15.4a and the upcoming IEEE802.15.6 standard, is presented. The complete, duty-cycled transmitter provides +1dBm peak output power, consuming 4.4mW. The receiver front-end shows −88dBm sensitivity at 0.85Mbps and a digital synchronization algorithm enables real-time duty cycling, resulting...
This paper presents the design and some aspects of implementation of a highly dependable, safety-oriented kernel for real-time applications. It is specifically designed as an execution facility for a deterministic semi-formal model -- the OASIS model -- which allows to express and verify temporal behaviors and communications of a safety critical real-time application. This paper shows specifically...
The production needs and the more complex working sessions in agricultural field ask for machine cluster in order to achieve a parallel and complete treatment of crops and fields. All heterogeneous or homogeneous machines of the cluster, both in series and in parallel, have to be synchronized to match safety requirements and to comply with task control requirements. The synchronization specifications...
The ubiquitous presence of powerful low-power wireless systems on chip (SoC) able to operate in the Industrial, Scientific and Medical (ISM) band has brought a new enhanced operational choice for real-time Radio Control (RC) applications such as aircrafts and cars in the hobby grade category. Frequency Hopping Spread Spectrum (FHSS) has become the dominant transmission technique for the previously...
Rough sets theory can eliminate the redundant and imprecise information effectively and correctly in fault diagnosis, which improve the real time and has much advantage of transforming afterwards and regular equipment logistics support to real-time logistics support. So the research on equipment fault diagnosis based on rough sets theory has much signification. The paper applies one advanced reduction...
Networks for real-time systems have stringent end-to-end latency and jitter requirements. One cost-efficient way to meet these requirements is the time-triggered communication paradigm which plans the transmission points in time of the frames off-line. This plan prevents contentions of frames on the network and is called a time-triggered schedule (tt-schedule). In general the tt-scheduling is a bin-packing...
This paper presents a low power ultra-wide band digital receiver baseband architecture for handling IEEE 802.15.4a packets in real-time. Real-time processing allows duty cycling of the analog frontend, which is key to achieve low power consumption. The architecture consists of a programmable application specific instruction set processor and a set of application specific integrated circuits. The design...
In the recent years, multicore processor designs have become increasingly popular for embedded applications, but diversified inter-core communication mechanisms have led to the difficulties in software development, integration and migration. A unified, portable, and efficient inter-core communication mechanism would have helped reduce these difficulties significantly, but such a solution did not exist...
Clock inaccuracies cause serious problems and troublesome in distributed systems. The clocks of different processors need to be synchronized to limit errors. This is to have an efficient communication or resource sharing. Hence the clocks need to be monitored and adjusted continuously. Otherwise, the clocks drift apart. Similarly clock skew also introduces mismatch in time value of two clocks. Both...
Energy consumption is a major issue in the design of embedded systems that are battery-driven. At the architectural level energy savings can be realized by a diversity of mechanisms. This paper presents the energy-savings mechanisms that are part of the time-triggered architecture (TTA). The paper starts with a general section on energy dissipation in VSLI circuits and an outline of the architectural...
A screen wall is a widely used application in reality and has been implemented in various methods. Traditional implementation methods always adopt dedicated devices according to specific hardware, which leads to poor portability and limited function. Compared with traditional methods, computer technology conduces to powerful image processing function. Additionally, clearer picture transmission could...
An OFDM transmission system for aerial photography is provided in this paper. The system can process and transmit the SDTV data stream in real-time with a bandwidth of 2 MHz. The structures of the OFDM transmission system are described and the design and implementation of a PC-based receiver is discussed in detail and simulation and test results are also included in this paper.
Differing from applying steganography on storage cover media, steganography on voice over IP (VoIP) must often delicately balance between providing adequate security and maintaining low latency for real-time services. This paper presents a novel real-time steganography model for VoIP that aims at providing good security for secret messages without sacrificing real-time performance. We achieve this...
In real-time playing of network audio-video, because of delay and dithering, effective data caches processing and audio-video synchronization control must be carried out to resume time connection among data. A scheme of using DataSet to process data in caches is proposed. Synchronous control method of thread and arithmetic of audio-video synchronization playing are discussed in detail. The new scheme...
We demonstrate the real-time implementation of a FPGA-based coherent optical OFDM (CO-OFDM) receiver at 2.5-G samples/s, which successfully receives a subband of a 54-Gb/s multi-band CO-OFDM signal with a record-low error floor of 3.7 times 10-8.
Time-triggered (TT) Ethernet is a new real-time communication protocol that is fully compatible with Ethernet and provides in addition to the standard Ethernet service a deterministic real-time communication service for distributed real-time systems. This paper elaborates on basic concepts in real-time communication, elicits real-time communication requirements and discusses some innate conflicts...
Interprocess communication (IPC) is often applied to cooperative processes and IPC performance largely determine the processing time. Here, we propose an instant synchronous IPC mechanism for preferential processing of high-priority data. In addition, we present that the results of an evaluation using an application program by using an imprecise computational model.
Designing safe and predictable software for embedded applications is a considerable challenge, which has been addressed by the COMDES-II framework. This is a component-based software framework employing a timed multitasking model of computation supported by a run-time environment. This paper presents a real-time kernel implementing the run-time environment - the HARTEXmu kernel that has been specifically...
With the availability of large bandwidth and high data rates the transmission of data, voice and video over the Internet is gaining popularity. Voice-over-IP (VoIP) uses packetized transmission of speech over the Internet (IP network). However, at the receiving end; packets are missing due to network delay, network congestion (jitter) and network errors. This packet loss degrades the quality of speech...
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