Data Rate Information Research Articles

Low Probability of Intercept-Based Optimal OFDM Waveform Design Strategy for an Integrated Radar and Communications System

The integration of radar and communications systems can provide great advantages, such as enhanced efficiency, structure simplification, less occupied hardware resources, and interference mitigation, compared with traditional individual radar and communications applications. Extensive studies have presented achieving improved system performance, whereas the problem of low probability of intercept (LPI)-based waveform design for the integrated system is seldom discussed in the literature. In this paper, an LPI-based optimal orthogonal frequency multiplexing modulation (OFDM) waveform design strategy is developed for an integrated radar and communications system (IRCS). The dedicated transmitter in this system transmits integrated OFDM waveform for simultaneously target parameter estimation and downlink communications. The basis of the underlying strategy is to employ the optimization technique to design the integrated OFDM waveform of IRCS in order to minimize the total radiated power, while satisfying the specified requirements of target parameter estimation and data information rate. We analytically show that the resulting optimization problem is convex and can be solved by formulating the Karush–Kuhn–Tuckers optimality conditions. Numerical simulation results demonstrate that our proposed strategy can solve the waveform design problem in the IRCS with low complexity, and the LPI performance of the IRCS can efficiently be enhanced by utilizing the proposed integrated OFDM waveform design strategy.

Adaptive OFDM Integrated Radar and Communications Waveform Design Based on Information Theory

To improve the effectiveness of limited spectral resources, an adaptive orthogonal frequency division multiplexing integrated radar and communications waveform design method is proposed. First, the conditional mutual information (MI) between the random target impulse response and the received signal, and the data information rate (DIR) of frequency selective fading channel are formulated. Then, with the constraint on the total power, the optimization problem, which simultaneously considers the conditional MI for radar and DIR for communications, is devised, and the analytic solution is derived. With low transmit power, the designed integrated waveform outperforms the fixed waveform (i.e., equal power allocation). Finally, several simulated experiments are provided to verify the effectiveness of the designed waveform.

On the Use of Energy Storage Systems and Linear Feedback Optimal Control for Transient Stability

In this paper, we study a distributed control strategy that harnesses the highly granular data available in future power systems in order to improve system resilience to disturbances. Specifically, we investigate the role of external energy storage systems (ESSs) in stabilizing the dynamics of power systems during periods of disruption. We consider an information-rich multiagent framework and focus on ESS output control via linear feedback optimal (LFO) control to achieve transient stability. The LFO control scheme relies on receiving timely state information to actuate distributed ESSs in order to drive the synchronous generators to stability. We evaluate the performance of the LFO control on the 39-bus 10-generator New England test power system in the presence of ideal and nonideal conditions including communication latency, finite sampling rate, and sensor noise. The LFO controller is found to have a simple structure, be tunable, and to have fast response to achieving transient stability while being sensitive to information latency and data rate.

Context-Aware Information Diffusion for Alerting Messages in 5G Mobile Social Networks

In emerging fifth generation (5G) systems, mobile social networks are expected to play an important role to enable proximity-based content distribution among devices. In this paper, we address social-awareness aspects and device-to-device (D2D) communications for information diffusion solutions in emergency scenarios. Context-aware information is collected from a set of devices deployed in the environment and received data are integrated and elaborated at the cellular base station before being delivered. In such a framework, we model the expected information diffusion time by taking into account both networking- and sociality-related metrics. In particular, we introduce the so-called social intercontact time which is able to model the interaction frequency between the user and a generic social platform. The proposed approach is compared with alternative solutions where the dissemination process is either managed through direct links from the central base station, as a conventional multicast scheme, or with the support from proximity communications, as a D2D-enhanced multicast scheme. The results of a performance assessment study show that the proposed framework achieves considerable gains, up to 50%, in terms of overall information diffusion time and data rate per user equipment.

Suspicious Flow Forwarding for Multiple Intrusion Detection Systems on Software-Defined Networks

In recent years, there have been an increasing number of attacks on networks, such as the distributed denial-of-service attack. However, the traditional network is not sufficiently flexible to control the huge amount of traffic that now passes through an intrusion detection system. With SDN, which separates control planes and data planes for programmability, elasticity, and simplicity, it becomes possible to force traffic to pass through an IDS by simply rerouting or mirroring traffic to an IDS. This article focuses on how to distribute traffic to multiple IDSs in order to increase the detection of network attacks and balance IDS loads. A clustering-based flow grouping scheme that distributes flows according to routing information and flow data rate is proposed. Through experiments with a virtualized testbed, we show that the proposed scheme detects network attacks more quickly and achieves a better balance of traffic loads on the IDSs.

Inner Bounds on Performance of Radar and Communications Co-Existence

We investigate methods of co-existence between radar and communications systems. Each system typically considers the other system a source of interference. Consequently, the traditional solution is to isolate the two systems spectrally or spatially. By considering a cooperative radar and communications signaling scheme, we derive achievable bounds on performance for a receiver that observes communications and radar return in the same frequency allocation. We assume the radar and communications operations to be a single joint system. Bounds on performance of the joint system are measured in terms of data information rate for communications and a novel radar estimation information rate for the radar.

Integrated Biosensing Platform Based on a 1.74-mW −90-dBm Sensitivity Dual- Mode-Operation Receiver for IEEE 802.15.6 Human Body Communication Standard

Human body communication (HBC), a technique featuring low conduction loss and low interference by taking the advantages of the nature of body composition, has emerged as one of the most promising techniques toward next-generation wireless body area network (WBAN). The regulation of WBAN, IEEE 802.15.6, concerning the standard of physical layer has also been established in 2012. The intensity of electric field around body is affected by the transmission distance, quality of electrode-skin contact, and so on which results in wide variance in path loss. In addition, according to the measurement results, the equivalent capacitance of electrode-skin interface increases path loss significantly when noncontact transmission happens. To solve the problems, a low-power receiver with dual-mode operation is proposed in this paper. The receiver has been implemented in a standard 0.18-μm CMOS process measurement shows the receiver is fully functional with power consumption <;1.75 mW under 1.2 V supply voltage and compatible with IEEE 802.15.6 HBC layer. The chip size is 1.05 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Maximum voltage conversion gain can be 85.5 dB. Experimental sensitivity is up to -90 dBm under an information data rate of 164 kb/s. It has been demonstrated that the receiver provides successful text file transmission through human body with the fabricated sensing electrodes.

A Communication Model to Decouple the Path Planning and Connectivity Optimization and Support Cooperative Sensing

When multiple mobile robots (e.g., robotic equipment and unmanned aerial vehicles (UAVs)) are deployed to work cooperatively, it is usually difficult to jointly optimize the algorithms involving the following two aspects: finding optimal paths and maintaining reliable network connectivity. This is due to the fact that both these objectives require the manipulation of sensors' physical locations. We introduce a new relay-assisted communication model to decouple these two aspects so that each one can be optimized independently. However, using additional relay nodes is at the expense of an increased number of transmissions and reduced spectrum efficiency. Theoretical results based on mutual information and average data rate of the model reveal that such drawbacks can be compensated if the sensor nodes are carefully arranged into groups. Based on these results, we further propose a pairing strategy to maximize the spectrum efficiency gain. Simulation experiments have confirmed the performance of this strategy in terms of improved efficiency. We provide a simple example to demonstrate the application of this model in cooperative sensing scenarios where multiple UAVs are deployed to explore an unknown area.

Differential Frequency Hopping Systems Using Soft Decision Viterbi Decoding Algorithm

Differential frequency-hopping (DFH) technique has been widely studied and applied in the military communications due to its many desirable features, such as reliable high data rate transmission characteristics, anti-jamming abilities and information security. In order to improve the information security of the conventional DFH systems, a novel DFH system with the G-function controlled by the well-known maximal length sequences, is proposed in this paper. In addition, both BCH code and soft decision Viterbi algorithm are also used in the proposed scheme to further improve the system performance. Our results show that the proposed scheme not only provides the higher information security but also improves the system performance indeed, compared to the conventional schemes.

Out-of-Band Emission Reduction Technique for OFDM and MC-CDMA Systems

In this paper, we introduce a method for out-of-band power reduction of multicarrier communication systems. Recent years MC systems possess a dominated role in wireless access due to ability to achieve high data rates and simultaneously high robustness to multipath and fading. Despite all advantages, MC transmission produces an essential out-of-band interference. The OOB radiation leads to the wastage of scarce spectral resources and severe threats to adjacent wireless channels. We propose a novel technique for reducing OOB radiations in OFDM and MC-CDMA systems. To reduce the OOB emissions in the MC-CDMA system, we propose analytical criterion for spectrum efficiency estimation as far as low complexity algebraic algorithm for the proper waveform selection. The structure of selected waveform provides suppression for radiation outside the signal necessary bandwidth. Being implemented in the OFDM system, proposed algorithm is used for calculation of phases of cancellation carriers suppressing most powerful OOB sidelobesin transmitted signal. In the final part of document we consider primer of the simple precoding procedure for OFDM systems which by 10 dB or more reduces the OOB power at the cost of inessential decrease of the information data rate. 1

Semi-Distributed Power and Subcarrier Allocation in LTE Hetnet System

In order to provide the large coverage and high data rate in future system, more and more low power nodes (LPNs) e.g., pico nodes, relay nodes, etc., are introduced into the LTE heterogeneous network (HetNet). The resource allocation and optimization scheme is the key issue in Hetnet system since the interference environment is quite complicated compared with the traditional homogenous networks. In this paper, the semi-distributed power and subcarrier allocation scheme is proposed, which aims to achieve the good performance tradeoff between the macro eNBs and the pico nodes. One novel utility function is investigated taking both macro edge UEs and pico edge UEs into account based on limited average data rate information exchanges between macro eNB and pico eNBs. The interference for the edge UEs can be coordinated efficiently due to the dynamic power and subcarrier allocations. Compared with the proportional fairness (PF) scheduling algorithm, the simulation results show that the proposed semi-distributed scheme can achieve about 8% throughput gain in average cell throughput. Furthermore, the pico edge UEs, and macro edge UEs of the proposed scheme can achieve 17%, 12% capacity gain, respectively.

Artificial Neural Network Based Vertical Handoff Algorithm for Reducing Handoff Latency

One of the most challenging topics for next generation wireless networks is vertical handoff concept since several wireless technologies are assumed to cooperate. Plenty of parameters related to user preferences, application requirements, and network conditions, such as; data rate, service cost, network latency, speed of mobile, battery level, interference ratio and etc. must be considered in vertical handoff process along with traditional RSSI information. In this study, a new artificial neural network based handoff decision algorithm is proposed in order to reduce the handoff latency of smart terminal deployed in aforementioned wireless heterogeneous infrastructures. The prominent parameters data rate, monetary cost and RSSI information are taken as inputs of the developed vertical handoff decision system. Performance results of the proposed system are also compared with those of classical Multiple Attribute Decision Making method Simple Additive Weighting, and of some other artificial intelligence based algorithms. According to the results obtained, the proposed neural network based vertical handoff decision algorithm is able to determine whether a handoff is necessary or not properly, and selects the best candidate access network considering the abovementioned parameters. The results also show that, the neural network based algorithm developed significantly reduces the handoff latency while the number of handoffs, which is another vital performance metric, is still reasonable.

New Passenger Services in Railway Stations Based on Mode Group Diversity Multiplexing Optical Fiber Communications

Nowadays, because of its wide bandwidth and high communication capability, the optical fiber is more and more used for high data rate transmission of information in railway environments. Conventionally, only one service is sent over the fiber at a time. However, many different services can be simultaneously conveyed in railway stations such as passenger information service, cellular phone, Wi-Fi… The objective of the work proposed in this paper is to demonstrate the potential benefits of transmitting radio signals over fiber in a railway environment. The main idea is to exploit the full capacity of the fiber by transmitting multiple services using the same fiber. Since, different services are operating in different frequency bands; we propose a new multiplexing technique called Mode Group Diversity Multiplexing (MGDM) to ensure the transmission of multiple services using the same fiber, without additional infrastructure. There are numerous advantages of the proposed technique, e.g., faster and reliable data exchange, high resolution video surveillance capability, high data rate information exchange in railway stations. We present, in this paper, the physical characteristics of optical fibers, performance of MGDM multiplexing technique, and the influence of the laser excitation conditions at the entrance of the fiber on the performances of the system.

Algebraic method for blind recovery of punctured convolutional encoders from an erroneous bitstream

To enhance the quality of transmissions, all digital communication systems use error-correcting codes. By introducing some redundancy in the informative binary data stream, they allow one to better withstand channel impairments. The design of new coding schemes leads to a perpetual evolution of the digital communication systems and, thus, cognitive radio receivers have to be designed. Such receivers will be able to blind estimate the transmitter parameters. In this study, an algebraic method dedicated to the blind identification of punctured convolutional encoders is presented. The blind identification of such encoders is of great interest, because convolutional encoders are embedded in most digital transmission systems where the puncturing principle is used to increase the code rate to reduce the loss of the information data rate because of the redundancy introduced by the encoder. After a brief recall of the principle of puncturing codes and the construction of the equivalent punctured code, a new method dedicated to the blind identification of both the mother code and the puncturing pattern is developed when the received bits are erroneous. Finally, case studies are presented to illustrate the performances of our blind identification method.

UWB Communication System Based on Bipolar PPM with Orthogonal Waveforms

In many classic Ultra Wide Band communication systems, only Gaussian and monocycle pulses associate to PPM modulation are used. In this paper, an original communication system based on orthogonal functions and the Bipolar PPM modulation is proposed. This system allows good performances in terms of Bit Error Rate (BER) and high data rate. This study concerns new applications, such as Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication systems or a wireless link between computers. These applications need high reliability to transmit security-related information and high data rate to exchange multimedia data. With the emergence of the orthogonal wave-forms, the performances of the UWB communication system will be more interesting in terms of BER and data rate. In this paper, two kinds of improvement are proposed. The first improvement permits us to decrease the Bit Error Rate using the original waveforms. The second allows improving the data rate via novel modulation method. The last parameter study, in this paper, concerns the problem of synchronization between the different users. We will study the performances of the proposed system in multiusers environment in synchronous and asynchronous cases. In the first stage, the theoretical and simulation results will be presented for the proposed system. The simulation results obtained by comparing the classic UWB system and the proposed system show that our solution gives good performances in terms of BER and data rate. The theoretical results of BER values will be given for our proposed solution. In the second stage, we will compute BER values for different jitter effects. Theses studies report theoretical and simulation performances evaluation in the case of two users

A Cross-Layer Delay Differentiation Packet Scheduling Scheme for Multimedia Content Delivery in 3G Satellite Multimedia Systems

The design of efficient packet scheduling algorithms, which play a key role in the radio resource management (RRM), is crucial for the multimedia delivery in the satellite digital multimedia broadcasting (SDMB) system. In this paper, a novel packet scheduling scheme, which uses the cross-layer approach in its design, is proposed. This scheme comprises a new service prioritization algorithm and a dynamic rate matching based resource allocation algorithm, aimed at utilizing both the applications' QoS attributes and the physical layer data rate information. The performance of the proposed scheme has been evaluated via simulation. In comparison with existing schemes, the proposed scheme achieves significant performance gain on delay, delay variation and physical channel utilization.

Watermark Bit Rate in Diverse Signal Domains

A study of the obtainable watermark data rate for information hiding algorithms is presented in this paper. As the perceptual entropy for wideband monophonic audio signals is in the range of four to five bits per sample, a significant amount of additional information can be inserted into signal without causing any perceptual distortion. Experimental results showed that transform domain watermark embedding outperforms considerably watermark embedding in time domain and that signal decompositions with a high gain of transform coding, like the wavelet transform, are the most suitable for high data rate information hiding. Keywords—Digital watermarking, information hiding, audio watermarking, watermark data rate. I. INTRODUCTION nformation hiding techniques have developed a strong basis an area with a growing number of applications like digital rights management, covert communications, annotations, etc. In all applications given above, data hiding techniques have to satisfy two basic requirements. The first requirement is perceptual transparency, i.e. cover object (object not containing any additional data) and stego object (object containing secret message) must be perceptually indiscernible. The second constraint is high data rate of the embedded data. The simplest visualization of the requirements of information hiding in digital audio is so called magic triangle, given in Figure 1. This model is convenient for a visual representation of the required trade-offs between the capacity of the watermark data and the robustness to certain watermark attacks, while keeping the perceptual quality of the watermarked audio at an acceptable level. It is not possible to attain high robustness to signal modifications and high data rate of the embedded watermark at the same time. Therefore, if a high robustness is required from the watermarking algorithm, the bit rate of the embedded watermark will be low and vice versa, high bit rate watermarks are usually very fragile in the presence of signal modifications. However, there are some applications that do not require that the embedded watermark has a high robustness against signal modifications. In these applications, the embedded data is expected to have a high data rate and to be detected and decoded using a blind

Multiple-Input–Multiple-Output Coherent Time Reversal Communications in a Shallow-Water Acoustic Channel

A recent time reversal (TR) experiment demonstrated that multiple foci can be projected from an array of sources to the same range but at different depths. This multiple input/multiple output process can potentially increase the information data rate. This paper presents experimental results of coherent TR communications (binary phase-shift keying, quaternary phase-shift keying, and 8-quadratic-amplitude modulation) at 3.5 kHz with a 1-kHz bandwidth where different messages were sent simultaneously to either two or three different depths at an 8.6-km range in a 105-m-deep water

Simultaneously multiple-depth coherent communications using time reversal

A recent time reversal experiment demonstrated that multiple foci can be projected from an array of sources to the same range but at different depths. This ‘‘multiple input, multiple output (MIMO)’’ process potentially can improve the information data rate. This paper presents the experimental results of binary phase shift keying (BPSK) communications at 3.5 kHz with a 500-Hz bandwidth where two different messages were sent simultaneously to different depths at 9-km range in 110-m-deep shallow water.

Iterative demodulation and decoding of high‐order CPM signals in Rician fading channels

AbstractSpace communications require high data rate information transmission at low bit error rate (BER). In this paper, we present a pilot symbol‐assisted, iterative demodulation and decoding system for high‐order continuous phase modulated (CPM) signals. We consider CPM signals because they are especially suitable for space communications due to their high spectral efficiency and constant envelope property.Coherent demodulation is adopted because of its superior BER performance over non‐coherent demodulation like differential detection. To track the time‐varying channel state information (CSI) caused by the Doppler effect in space communications, pilot symbols are inserted periodically in the data stream to serve as references for channel estimation. Due to the inherent memory in continuous phase modulation, those pilot symbols are set to be data dependent so that the CPM phase trellis can be forced to some pre‐defined reference state at certain time epochs. In addition, pilot symbols are used as parity check symbols in demodulating each pilot frame to help reduce decoding errors. Powerful forward error correcting codes (convolutional codes) are then combined with the phase trellis of the CPM signal to form a structure similar to serial concatenated convolutional codes so that the BER performance can be significantly improved by applying iterative processing. Compared with other joint detection and decoding systems, the proposed system has high power‐bandwidth efficiency and low computational complexity by using pilot symbols to separate channel estimation from demodulation, which is even more significant in high‐order modulation.To further improve the receiver performance, information is exchanged between the CPM demodulator, the convolutional decoder, and the channel estimator. First, the channel estimator uses the information from CPM demodulator to construct an estimate of the phase trajectory of the transmitted signal and filters all received samples on this estimated phase trajectory to obtain a more accurate estimation of the CSI. Then the CPM demodulator combines this newly estimated CSI with the extrinsic information from the convolutional decoder to generate more reliable soft decisions, which is to be used as input to the convolutional decoder. This process can be carried out iteratively to improve the BER performance. Although there may be some errors in reconstructing the phase trajectory which will cause an increase in channel estimation errors, the number of errors will decrease at high signal‐to‐noise ratio and the accuracy of the estimated CSI will improve due to the increased sampling rate.At last, it should be pointed out that although the proposed system is designed for CPM signals, it applies in general to other signals modulated with memory such as differential phase‐shift keying. We have already obtained similar results for differential QPSK in Rician fading channels. Copyright © 2002 John Wiley &amp; Sons, Ltd.