In this paper, we consider a resource allocation scheme for millimeter wave–based wireless personal area networks using directional antennas. This scheme involves scheduling the reservation period of medium access control for IEEE 802.15.3c. Objective functions are considered to minimize the average delay and maximize throughput; and two scheduling algorithms—namely, MInMax concurrent transmission and MAxMin concurrent transmission—are proposed to provide a suboptimal solution to each objective function. These are based on an exclusive region and two decision rules that determine the length of reservation times and the transmission order of groups. Each group consists of flows that are concurrently transmittable via spatial reuse. The algorithms appropriately apply two decision rules according to their objectives. A real video trace is used for the numerical results, which show that the proposed algorithms satisfy their objectives. They outperform other schemes on a range of measures, showing the effect of using a directional antenna. The proposed scheme efficiently supports variable bit rate traffic during the reservation period, reducing resource waste. 相似文献
In this paper, we introduce the integer-valued generalized autoregressive conditional heteroscedasticity (INGARCH) as a network traffic prediction model. As the INGARCH is known as a non-linear analytical model that could capture the characteristics of network traffic such as Poisson packet arrival and long-range dependence property, INGARCH seems to be an adequate model for network traffic prediction. Based on the investigation for the traffic arrival process in various network topologies including IoT and VANET, we could confirm that assuming the Poisson process as packet arrival works for some networks and environments of networks. The prediction model is generated by estimating parameters of the INGARCH process and predicting the Poisson parameters of future-steps ahead process using the conditional maximum likelihood estimation method and prediction procedure, respectively. Its performance is compared with those of three different models; autoregressive integrated moving average, GARCH, and long short-term memory recurrent neural network. Anonymized passive traffic traces provided by the Center for Applied Internet Data Analysis are used in the experiment. Numerical results show that the proposed model predicts better than the three models in terms of measurements used in prediction models. Based on the study, we can conclude the followings: INGARCH can capture the characteristics of network traffic better than other statistic models, it is more tractable than neural networks (NNs) overcoming the black-box nature of NNs, and the performances of some statistical models are comparable or even superior to those of NNs, especially when the data is insufficient to apply deep NNs.
In this paper, the directional carrier sense multiple access/collision avoidance (CSMA/CA) protocol in the immediate acknowledgement mode for IEEE 802.15.3c is analyzed under saturation environments. For the analysis, a sensing region and an exclusive region with a directional antenna are computed probabilistically and a Markov chain model in which the features of IEEE 802.15.3c and the effects of using directional antennas are incorporated is analyzed. An algorithm to find the maximal number of concurrently transmittable frames is proposed. The system throughput and the average transmission delay are obtained in closed forms. The numerical results show the impact of directional antennas on the CSMA/CA media access control (MAC) protocol. For instance, the throughput with a small beamwidth of antenna is more than ten times larger than that for an omnidirectional antenna. The overall analysis is verified by a simulation. The obtained results will be helpful in developing an MAC protocol for enhancing the performance of mmWave wireless personal area networks. 相似文献
Two supervised learning algorithms, a basic neural network and a long short‐term memory recurrent neural network, are applied to traffic including DDoS attacks. The joint effects of preprocessing methods and hyperparameters for machine learning on performance are investigated. Values representing attack characteristics are extracted from datasets and preprocessed by two methods. Binary classification and two optimizers are used. Some hyperparameters are obtained exhaustively for fast and accurate detection, while others are fixed with constants to account for performance and data characteristics. An experiment is performed via TensorFlow on three traffic datasets. Three scenarios are considered to investigate the effects of learning former traffic on sequential traffic analysis and the effects of learning one dataset on application to another dataset, and determine whether the algorithms can be used for recent attack traffic. Experimental results show that the used preprocessing methods, neural network architectures and hyperparameters, and the optimizers are appropriate for DDoS attack detection. The obtained results provide a criterion for the detection accuracy of attacks. 相似文献
Wireless Networks - In this paper, we propose a game theoretic framework to analyze a passive eavesdropping attack in millimeter-wave-based wireless personal area networks. As the interaction... 相似文献
In this paper, the effect of packet length on the throughput is studied in millimetre-wave band based Wireless Personal Area Networks. A device has a finite queue and uses a directional antenna. A Markov chain model is considered for no-ACK mode in directional carrier sense multiple access with collision avoidance under error-prone channel and saturation environments. The features of Medium Access Control of IEEE 802.15.3c such as freezing of backoff counter are considered in the model. The effects of directional antennas and bit error rate are also considered. The throughput and delay including queuing delay are analysed, and the optimal packet length is derived by analysing the throughput. The numerical results show that the longer packets are preferred in the environment that the number of contending devices is small and the beamwidth is narrow. In addition, the optimal packet length maximising throughput is derived, which depends on several parameters such as beamwidth, the number of devices, and the bit error rate. The obtained results provide the criterion in determining the packet length for effective resource utilisation. 相似文献
The algorithm of scheduling scheme of channel-aware priority-based groupwise transmission is investigated for non-real time data service for the uplink direct sequence code division multiple access (DS/CDMA) system using the burst-switching scheme to support the integrated voice/data service. The proposed scheme optimally determines the transmission-time groups and assigns optimal data rates to the users with packets in the transmission-time group depending on priority metric, which involves several parameters such as delay threshold, waiting time, length of packet, and state of the channel, in a way of minimizing the average transmission delay. Simulation results show that the proposed algorithm gives better performance of average transmission delay and packet loss probability than any other conventional algorithms. 相似文献
This paper presents an analysis of resource assignment for multihop communications in millimeter‐wave (mm‐wave) wireless personal area networks. The purpose of this paper is to figure out the effect of using directional antennas and relaying devices (DEVs) in communications. The analysis is performed based on a grouping algorithm, categorization of the flows, and the relaying DEV selection policy. Three schemes are compared: direct and relaying concurrent transmission (DRCT), direct concurrent transmission (DCT), and direct nonconcurrent transmission (DNCT). Numerical results show that DRCT is better than DCT and DCT is better than DNCT for any antenna beamwidths under the proposed algorithm and policy. The results also show that using relaying DEVs increases the throughput up to 30% and that there is an optimal beamwidth that maximizes spatial reuse and depends on parameters such as the number of flows in the networks. This analysis can provide guidelines for improving the performance of mm‐wave band communications with relaying DEVs. 相似文献