Abstract In this paper, we propose a novel method for web layer anomaly detection. In contrast to the majority of other state of the art approaches, we do not adapt manually configured parsers or packet content type detection techniques to partition the request sent from clients to server. In our experiments, we showed that making certain assumptions about the request content types may lead to the degradation of the detection performance. Therefore, we proposed unsupervised algorithm for automated packet structure extraction. We formulate this as the optimisation problem that is solved by means of genetic algorithm. Moreover, on top of the request segmentation schema, we provide the set of algorithms that measure statistics and apply machine learning techniques to solve the classification problems. The effectiveness of our methods is proved by the results achieved on the extended benchmark database. Copyright © 2016 John Wiley & Sons, Ltd.

Abstract In this paper, a framework for recognizing network traffic in order to detect anomalies is proposed. We propose to combine and correlate parameters from different layers in order to detect 0‐day attacks and reduce false positives. Moreover, we propose to combine statistical and signal‐based features. The major contribution of this paper is novel framework for network security based on the correlation approach as well as new signal‐based algorithm for intrusion detection on the basis of the Matching Pursuit (MP) algorithm. As to our best knowledge, we are the first to use MP for intrusion and anomaly detection in computer networks. In the presented experiments, we proved that our solution gives better results than intrusion detection based on discrete wavelet transform.

Authors propose to use cell level simulation as a natural follow up of the link level tests and a preliminary stage of the systematic approach to the system level tests in the context of IMT-Advanced candidates performance evaluation. The system under test (SUT) consists of flexible realizations of the WiMAX physical layer abstraction (providing customized fidelity and thus simulation complexity) with the nb-LDPC codes. The preliminary assessment of system capacity under quasi-mobility conditions (with ACM) is performed using human mobility models and freeware software for radio coverage planning. Moreover two symbol reservation schemes are evaluated in terms of effective bandwidth utilization, blocking and dropping probability. Complete sharing admission control mechanism (CSCAC) is used to show system performance under various load and mobility patterns. It is shown that using nb-LDPC codes improves system throughput in poor radio conditions as compared to RS-CC coding as in the IEEE 802.16e-2005 specification.

In this paper, we deal with convolutionally encoded MSK, DMSK and TFM signals. The matched convolutional encoding technique is used which was shown earlier to lead in some eases to the optimum Viterbi demodulation/decoder which is not more complex than the optimum receiver for the uncoded signal. Results of a systematic search for such cases are presented and discussed.>

The current situation of land mobile radio (LMR) systems in Poland is described. This includes paging, dispatch, trunking, and cellular systems. Frequency plan and organization of LMR communication in Poland are presented. Finally, the plan for the future development of LMR systems in Poland, prepared by the Ministry of Telecommunications, is summarized.>

A matched code is a convolutional code chosen in such a way that when combined with modulation with memory the resulting receiver for the coded modulation has the smallest possible number of states. In the paper, the matched coding technique is applied to coded tamed frequency modulation (TFM) schemes and a formal procedure is developed to find the best combination of a code and a modulation. The optimization criterion is the maximum free Euclidean distance for a given code rate and a given number of states in the Viterbi receiver used for the coded modulation. A search for the best codes was carried out for code rates 1/2 and 2/3, and for receivers with up to 256 and 64 states, respectively. Good coding gains (more than 7 dB for rate 1/2) were achieved. Some of the best codes were catastrophic, yet the coded modulation was not. The codes obtained using the matched coding approach were in many cases better than those obtained using traditional optimization techniques.>

Multi-T phase codes are an equivalent realization of multi-h phase codes within the class of continuous phase modulations (CPM). The authors present, in the form of code tables, the results of a systematic search for binary and quaternary multi-T phase codes which maximize the free Euclidean distance under given bandwidth and complexity constraints.>

It has been believed that the superiority of multi-h phase codes over constant-h continuous-phase frequency shift keying (CPFSK) schemes is based entirely on the longer temporal separation of any two signal paths. This assumption forces the number of states in the receiver to be lower bounded and requires a fast processor in the receiver. Counterexamples to this common belief are presented as well as results of a systematic search for good multi-h codes for a given bandwidth and complexity constraints. It is shown that quaternary multi-h codes exist for which the first merge of the phase paths in the phase tree is not delayed as compared to the CPFSK scheme, yet which still offer a significant coding gain over the corresponding CPFSK signals. Some quaternary and octal multi-h codes are found with large minimum distance values and a smaller number of receiver states than those known previously.>

Multi-h and multi-T phase codes, two classes of continuous phase modulation (CPM) with cyclically varying values of modulation index, are compared. The multi-h receiver with decision-directed carrier recovery loop is simulated for multi-T codes. The simulation study shows that despite a different signal shape, the error performance and synchronization properties of the two classes of codes are similar.>

A multi-Trealization of multi-hphase codes is considered, and distance structure and spectral properties are investigated.