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In order to improve the ability of defect detection and effective testing of multimedia application software, the technology of defect data generation of multimedia application software for group users is proposed. The defect data generation model of group users’ multimedia application software is constructed. Adaptive software vulnerability information detection protocol is adopted to realize balanced reorganization of transmission links and link structures. Impulse response characteristic quantities of transmission links of group users’ multimedia application software are extracted. According to peak detection results of impulse response, defect information fusion and feature location identification of group users’ multimedia application software are carried out. The improved neural network model is adopted to realize automatic generation of defect data of group users’ multimedia application software and self-organizing repair of defects of group users’ multimedia application software. The simulation results show that this method has good balance and strong feature clustering in generating defect data of group users’ multimedia application software, and improves the reliability detection ability of group users’ multimedia application software.

The increasing small data package transmission from the prosperously growing number of deployed networks, connected devices and multi-media applications has triggered the study of new technologies to have optimized spectrum utilization. Non-orthogonal multiple access (NoMA) has been proposed in both academic and industry as a promising technology to achieve such purpose by providing the ability to serve massive user equipment (UE) and exploit the properties of small data transmission. In addition to the intra-cell multi-user interference handling, an evolved operation of a NoMA scheme with bit-level interleaving and symbol level grid mapping is proposed in this paper to solve its major issue in practical communication systems: inter-cell interference (ICI). Theoretical analysis and simulation evaluations are provided and the results show that the proposed method can effectively mitigate the inter-cell interference, and hardware test-bed also proves robust BLER performance could be achieved under multi-cell scenarios.

The fundamental differences between LTE system and the lately built 5G-NR system are relying on the multi-subcarrier spacing (SCS) and multi-analog-beam powered operations. Such variation creates the motivations to have a new design on the physical random access channel (PRACH) preamble generation method as well as the random access protocol. In the proposed OFDM baseband signal generation for PRACH, the signal is placed in between of the data channels as middle as possible in order to alleviate the potential interference from neighboring subcarriers. Also, the proposed protocol design takes the impact of multi-beam capability into account. The design of single Msg.1 with multi-beam operation and application of multiple Msg.1 are both studied. The simulation results are presented to illustrate the performance of our proposed random access solutions.

New multiple access method has been recognized as an enabling technology for fifth-generation (5G) communication system. To fulfill the requirement on higher user density/network throughput, conventional orthogonal multiple access schemes have certain limitation on the user-capacity by only configuring the resource to one user. In this paper, an advanced non-orthogonal multiple access (NoMA) scheme is proposed, namely as interleave-grid multiple access (IGMA). Based on the bit level interleaving and symbol level grid-mapping process, the IGMA can provide tremendous user multiplexing capability as well as BLER performance. Joint detection and decoding technique is utilized at the receiver side considering both the complexity and the achievable performance. Moreover, the link level and system level simulation results are represented to verify the performance of IGMA, some initial hardware evaluation is also given.

In this paper, we proposed a computing resource allocation scheme based on users' SNR condition, to achieve the maximal throughput of wireless networks. So far, most research on radio resource allocation assumed the computing ability is infinite for digital signal processing. In our paper, we assume that the computing resource is limited, and consider the centralized computing scenario, which is popular in the next generation wireless radio access network architecture. First we model the computing ability by iteration times, then we propose the adaptive allocation scheme based on SNR condition. Simulation results show that the proposed scheme can obtain 0.5 dB improvement of system throughput compared with traditional scheme.

In this paper, a low PAPR interleaving based non-orthogonal multiple access (NoMA) scheme is introduced. By utilizing the property of DFT spread OFDM (DFT-s-OFDM), the peak-to-average power ratio (PAPR) can be reduced compared with existing NoMA schemes without sacrificing achievable data rates. Meanwhile, a low-complexity detection algorithm is also proposed on top of the elementary signal estimator (ESE) with the joint Gaussian distribution assumption, which can maintain good detection performance with moderate detection complexity. Simulation results, including PAPR and BLER performance, show that the proposed scheme can provide good performance with lower PAPR, which is suitable for mMTC scenario for 5G.

With the rapid development of information security technology, Network Based Intrusion Protecting Devices(NIPD), like firewall and NIDS, holding the function of detecting and blocking network attacks, have become the primary security guard of critical information infrastructure, significantly reduced the security threat of network attack. Regarding these features, attackers are continuously pursuing efficient ways for obfuscating attack behaviors to evade from the detecting mechanism of NIPD. Once the NIPD deployed in the network boundary is found vulnerable, malicious attackers can bypass it with advanced evasion technology to deliver an exploit, making the protected network information infrastructure be directly exposure to network threats from outside, which brings in security risks and results in serious consequence. So doing research on the testing technology for the evasion resilience capability of NIPD is critical. This paper first introduced the working mechanism of NIPD, providing a comprehensive survey on the achievements on the field of current evasion resilience testing technology. Then, the defects of the current work are analyzed and improvements on the corresponding work are described accordingly. Finally, the further research directions in this field is discussed in detail.

In a time-division duplex (TDD) based multi-input single-output (MISO) system, the channel state information (CSI) can be obtained during the channel estimation phase in which the receiver transmits the pilot symbols to the transmitter. This scheme may suffer from a so-called pilot spoofing attack, i.e., an adversary may send identical pilot signals as those of the legitimate receiver to spoof the transmitter. The resultant channel estimate may then contain the CSI of both legitimate and illegitimate receivers, and if such estimated channel is used for transmit beamforming, the information dedicated for legitimate receiver will leak to the illegitimate receiver. In this paper, we study the detection and defending strategies for such pilot spoofing attack. A two-way training based scheme is proposed. The durations of the training periods are also designed to optimize the secrecy rate. Finally, numerical results are presented to show the performance of our proposed method.

As one of the most popular industrial network protocol used in the energy distribution field, the security, especially vulnerability of Modbus-TCP protocol has attracted great attentions from both academic and industrial field. Due to the Particularity of Modbus-TCP, traditional fuzzing framework for vulnerability detecting cannot work efficiently. To overcome this drawback, a special smart fuzzing technology for Modbus-TCP is proposed, the architecture is described in detail, an adaptive algorithm for test case generating and the workflow of the testing process are presented, which can smartly generate test case according to the feedback from target. The result of the simulation experiment show that the mechanism described can satisfy the requirement of the vulnerability detecting for Modbus-TCP well. What's more, compared with traditional fuzzing framework, the quality of the test case and the efficiency of the process are apparently improved without losing the coverage.

We study a spoofing attack happened in the physical layer of a multiple-antenna system, where an adversary tries to spoof the transmitter by sending the identical pilot (training) signal as that of a legitimate receiver in the uplink channel estimation phase. This attack, named as pilot spoofing attack, could lead to a secrecy information leakage to the adversary and information rate decrease at the legitimate receiver. Due to the serious results caused by the pilot spoofing attack, we propose an energy-ratio detector (ERD) to protect the legitimate components. The ERD makes the decision by exploiting the asymmetry of the received signal strength (RSS) between the transmitter and the legitimate receiver when the system is under the pilot spoofing attack. Numerical results are presented to illustrate the effectiveness of our proposed detector.

In this paper, secure transmission is considered in a wireless relay network in the presence of an eavesdropper. A novel hybrid relay scheme, named as relaying-and-jamming (RJ), is advocated to achieve information theoretical security. In the RJ scheme, the relay node is equipped with multiple antennas. It responses for two missions: re-transmitting the information signal from source code and broadcasting the jamming signal to degrade eavesdropper's channel. The objective of this paper is to maximize the achievable ergodic secrecy rate. We are interested in the scenario that eavesdropper's instant channel state information (CSI) is unknown, in which the ergodic secrecy rate expression is derived. The optimal power allocation between information signal and jamming signal at the relay node is found statistically to achieve the largest ergodic secrecy rate. Simulation is carefully designed and respective results are presented to confirm the theoretical analysis and compare with existing work.

Physical layer security in wireless networks has received increasing attention in recent years. In this paper, we consider multiple-input single-output (MISO) fading wiretap channels, where the transmitter utilizes artificial noise-aided precoding (ANaP) transmission strategy to maximize the secrecy capacity of the channel. When the channel state information (CSI) of Eavesdropper's (Eve's) channel is known at Alice, we prove that the optimal ANaP strategy reduces to the conventional precoding strategy, i.e., all the transmit power should be allocated to the precoding of information signal. When the CSI of Eve's channel is unknown at Alice, we find that there exists an optimal power allocation ratio between the information signal and the artificial noise and that this power ratio depends on the number of antennas as well as the available transmit power at Alice. In particular, when the available transmit power at Alice increases or the number of antennas at Alice decreases, more power should be allocated to the artificial noise.

Steganalysis is the opposite art to steganography, whose goal is to detect whether or not the seemly innocent objects like image hiding message. With the explosive growth of the Internet information. Making real time image steganalysis online to detect the malicious use of multimedia documents for covert communication has become more and more difficult. Traditional research on image steganalysis mainly focus on how to improve the accuracy of Steganalysis, few of them pay much attention on the efficiency of the Image Steganalysis technology and the architecture optimizing for Steganalysis service providing. Regarding this problem, this paper proposed a Image Steganalysis Technique Based on Cloud Computing and BP Neutral Network, the structure and workflow of the system is introduced in detail. The result of simulation experiment proves that the import of cloud computing architecture can apparently improve the efficiency of image Steganalysis in the environment of internet and the accuracy of Steganalysis algorithm is acceptable instead of being greatly affected by system load.