Secure centralized spectrum sensing for cognitive radio networks

Spectrum utilization becomes more and more important while new communication techniques keep increasing and the spectrum bands remain finite. Cognitive radio is a revolutionary technology to make use of the spectrum more effectively. In order to avoid the interference to the primary user, spectrum sensing must be sensitive and reliable. Cooperative spectrum sensing (CSS) is one of the ways to increase the reliability of spectrum sensing. The information fusion technique is a key component of CSS. In this paper, we proposed a novel fusion scheme based on spatial correlation technique. We utilize geographical information with reputational weights to propose a two-level fusion scheme called secure centralized spectrum sensing (SCSS). The simulation results show that as the attackers present high density aggregation at some areas, the correct sensing ratio of SCSS is increasing as well even when the number of attackers is very large.     

Constructing secure group communication over wireless ad hoc networks based on a virtual subnet model

Recently, more and more people have begun using mobile devices such as PDAs and notebooks. Our lives have been profoundly affected by such devices. A MANET, a mobile ad hoc network, is an effective networking system facilitating an exchange data between mobile devices, without the support of wireless access points and base stations. A MANET is not restricted to unicast or multicast communication, but can also provide "many-to-many" transmission, which can be treated as a group communication. Until recently, however, the way in which such groups are formed had not drawn much attention. Because communication in wireless networks is broadcast and a certain amount of devices can receive transmitted messages, the risk of unsecured sensitive information being intercepted by unintended recipients is a real concern. Consequently, efforts to ensure the security of group communications in MANETs are essential. This article proposes a virtual subnet model to construct secure group communication over a MANET. With the model, the composition of groups is established as the forming of group keys. Our results show that this approach can completely satisfy the needs for both security and efficiency.     

Learning-Based Data Envelopment Analysis for External Cloud Resource Allocation

A mature cloud system needs a complete resource allocation policy which includes internal and external allocation. They not only enable users to have better experiences, but also allows the cloud provider to cut costs. In the other words, internal and external allocation are indispensable since a combination of them is only a total solution for whole cloud system. In this paper, we clearly explain the difference between internal allocation (IA) and external allocation (EA) as well as defining the explicit IA and EA problem for the follow up research. Although many researchers have proposed resource allocation methods, they are just based on subjective observations which lead to an imbalance of the overall cloud architecture, and cloud computing resources to operate se-quentially. In order to avoid an imbalanced situation, in previous work, we proposed Data Envelopment Analysis (DEA) to solve this problem; it considers all of a user’s demands to evaluate the overall cloud parameters. However, although DEA can provide a higher quality solution, it requires more time. So we use the Q-learning and Data Envelopment Analysis (DEA) to solve the imbalance problem and reduce computing time. As our simulation results show, the proposed DEA+Qlearning will provide almost best quality but too much calculating time.     

An Architecture and Communication Protocol for IPv6 Pack-Based Picocellular Networks

In this paper, micro mobility problems in handoff binding latency in Mobile IPv6 and the enhanced Cellular Mobile IPv6 (CMIv6) are investigated using a new extension protocol. Frequent and fast movements usually characterize micro mobility. An enhanced handoff extension is adopted to solve the Mobile IPv6 handoff break in a micro mobility environment. The basic idea involves using the new field in the IPv6 header, flow label, to assist the foreign router delivering packets to the mobile node. The Foreign Home Agent (FHA) is a new defined node in this proposition. FHA can accurately deliver packets according to the mobile node IP address even though the new binding messages have not arrived at the CN. The simulations shown in this paper prove that the enhanced CMIv6 scheme can minimize packet loss during handoffs.     

A novel user’s authentication scheme for pervasive on-line media services

Due to the explosive growth of the Internet and the pervasion of multimedia, protection of intellectual property (IP) rights of digital content in transactions induces people’s concerns. Current security requirements and copyright protection mechanisms especially need to work in real-time and on-line for communication and networking. For media service systems in the Internet, user’s authentication is most essential in association with the access control of the media system. The authentication scheme is a trivial but crucial issue for maintaining user’s information. Up to now, many one-time password-based authentication schemes have been proposed. However, none is secure enough. The purpose of a one-time password (OTP) is to make it more difficult to gain unauthorized access to restricted resources. Traditionally static passwords can more easily be obtained by an unauthorized intruder given enough attempts and time. By constantly altering the password, as is done with a one-time password, this risk can be greatly reduced. These schemes are specially fit for media services in the Internet since they will frustrate the attacker’s attempt. Lin, Shen and Hwang proposed a strong-password authentication scheme in association with one-time password by using smart cards, and claimed their scheme can resist guess attack, replay attack, impersonation attack and stolen attack. Later, Ku, Tsai, and Chen showed that Lin-Shen-Hwang’s scheme suffers from a replay attack and a denial-of-service attack. Furthermore, Ku proposed a hash-based strong-password authentication scheme to enhance the security. In this paper, we show the weaknesses and devise some attacks against Ku’s scheme. Then, we revise Ku’s scheme and propose a novel user’s authentication scheme in pervasive on-line media services for current communication and networking.     

A Collision Alleviation Scheme for IEEE 802.11p VANETs

IEEE 802.11p protocol, also known as Wireless Access for the Vehicular Environment provides dedicated short range communication for future Vehicular Ad Hoc Networks (VANETs). According to the IEEE 802.11p standard, the highest priority traffic transmission often suffers from the consecutive collisions in bursty arrival or congested scenarios because of the naive pre-assumption of a low level of congestion in the system, and thus results in emergent messages delayed. In this paper, we propose a simple, but yet well performing collision alleviation scheme to alleviate intensive collisions between highest priority access categories which usually used to schedule emergency message since safety is the most critical and promising issue in VANET. In addition to theoretical analysis, simulations are conducted to evaluate its performance. The simulation results show that the proposed scheme can not only increase the achievable channel throughput of the legacy protocol at most 15%, but also reduce the average packet access delay of the legacy protocol at least 5% and the packet collision probability at most 60% in congested VANET environments.     

Quantum Secure Communication Network Protocol with Entangled Photons for Mobile Communications

In this paper, we propose a communication protocol called Controlled Bidirectional Quantum Secret Direct Communication (CBQSDC) for mobile networks. In mobile networks, telecom companies assist the agent ensuring both sides could receive the other’s secret messages in the transmission by quantum theory simultaneously. This protocol is based on n-particle GHZ states (Greenberger-Horne-Zeilinger-states) which are transformed to Einstein-Podolsky-Rosen (EPR) pairs by entanglement swapping. GHZ states are used to carry both sides’ messages and entanglement swapping could reduce the number of transmission, so we could decrease the probability of eavesdropping. If any eavesdropper tries to steal dealer’s messages, the lawful participants will perceive it and abort their transmission.     

Micro-mobility mechanism for smooth handoffs in an integrated ad-hoc and cellular IPv6 network under high-speed movement

The success of the Internet has attracted more people to take part in network navigation. Numerous wireless-communication devices have rapidly evolved in the past decade. The demand for mobile communications is increasing and packet data services through Internet protocol (IP) networks have become a trend. To supply more IP addresses to network devices and improve network performance, a new IP version 6 (IPv6) was developed by the Internet Engineering Task Force in 1994. IPv6 supports certain features that make mobility management more efficient in mobile IP. A cellular architecture is needed to improve the communications quality and to reduce power consumption, both at the base and mobile stations. In a cellular environment, handoffs occur frequently. Reducing the defects caused by handoffs is extremely important in the mobile network environment. This is especially important for high-speed moving devices. In this paper, a handoff strategy called neighbor-assisted agent architecture, which takes advantage of the ad-hoc network to improve handoff performance, is proposed. Timing analytical and simulation results show that the proposed mechanism can provide a better solution than mobile IP for handoff breaks during high-speed movement.     

Performance Optimization with Efficient Polling Mechanism in IEEE 802.16 Networks with Cross-Layer Consideration

IEEE 802.16 standard suite defines a reservation-based bandwidth allocation mechanism. A SS (Subscriber Station) has to be polled to request bandwidth reservation before transmits uplink data to a BS (Base Station). In this mechanism exist two main polling modes: the unicast polling mode and the contention-based polling mode. The different polling operations in MAC (Medium Access Control) result in different PHY (PHYsical layer) frame structure that deeply affect the performance. Therefore, there should be an optimal scheme to adopt these two polling modes in order to optimize the performance. Although the standard defines five service classes to adaptively use the polling modes to fit the QoS (Quality of Service) requirements of different applications, it does not specify exactly a scheme to adopt these two polling modes efficiently and fairly during the polling process. In~this paper, we investigate the polling mechanisms in IEEE 802.16 networks, and focus the attention on the performance caused by different adoption schemes. We also propose a simple but efficient polling mechanism to optimize the performance. The simulation results verify that the performance is conditioned to the fulfillment of the polling mechanisms and our proposed optimal polling scheme can allocate bandwidth more efficient and achieve better performance.