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Network virtualization has emerged as the most promising approach to overcome the current ossification of the Internet. A key problem in it is how to efficiently and effectively make use of the substrate network resources by embedding multiple virtual networks with various constraints. Due to its NP-hardness, many heuristic approaches have been proposed. However, most of them simplify the problem...
This paper investigates a network information flow problem for a multiple-input multiple-output (MIMO) Gaussian wireless network with K-users and a single intermediate relay having M antennas. In this network, each user intends to convey a multicast message to all other users while receiving K-1 independent messages from the other users via an intermediate relay. This network information flow is termed...
In OFDMA-based Cognitive Radio (CR) systems, how to deal with the time-varying nature of avaliliable spectrum resources has become a hotspot and challenging problem in resource allocation. Traditional resource allocation algorithm can not guarantee proportional rates among non-real-time CR user (CRU) because the number of available subchannels is smaller than the number of CRUs in some OFDM symbol...
An RFID system generally consists of tags, readers, and backend servers with the readers charged with authenticating/identifying the tags with the help of the servers. Two important enhancements have been suggested for widespread adoption of RFIDs, namely the use of low cost (5?? or less) passive RFID tags and serverless system design to overcome the need for persistent connection between the readers...
Location privacy is one of the Quality of Privacies (QoP) in vehicular ad hoc network (VANET) and imperative for the VANET's full flourish. Frequent pseudonym changing can provide a promising solution to achieve location privacy, however if the pseudonyms are changed in an improper occasion, the solution is ineffective. In this paper, to improve the effectiveness of this kind of solution, we first...
Efficient network utilization is essential towards the deployment of large scale peer-to-peer (P2P) video live streaming services on the Internet. Push-pull hybrid schemes and pull schemes provide practical solutions to P2P video live streaming, but network utilization remains unaddressed. To the best of our knowledge, a study of network utilization in the context of P2P video live streaming does...
Plug-in electric vehicles (PEVs) will not only have a substantial influence on the emerging smart grid system but also create numerous challenges for the utility and customer to deal with their connections and charging. Authentication and authorization processes are critical elements to enable mass deployment of charging stations and to provide authorized customers to access the charging facility...
A new censoring cooperative spectrum sensing scheme in cognitive radio (CR) network is proposed in this paper, which is based on stochastic resonance (SR) technique and optimal censoring interval. The selection strategy for the optimal censoring interval is derived. The observations of the cooperative secondary users (SUs) whose statistics fall into the censoring interval are processed by SR system...
Continuous authentication is an important prevention-based approach to protect high security mobile ad-hoc networks (MANETs). On the other hand, intrusion detection systems (IDSs) are also important in MANETs to effectively identify malicious activities. Considering these two approaches jointly is effective in optimal security design taking into account system security requirements and resource constraints...
A cooperative spectrum sensing technique in cognitive radio (CR) networks is proposed in this paper, which is based on the data fusion of different stochastic resonance (SR) energy detectors. Due to the noisy uncertainty in the unpredictable wireless communication channel, the detection performance of the traditional energy detector cannot be guaranteed. By introducing the SR system with different...
In this paper, the blind and semiblind channel estimation and equalization are investigated for zero-padding single-carrier block transmission (ZP-SCBT) systems using second-order statistics. Unlike the conventional channel estimation techniques, the proposed approach focuses on identifying the inverse of the channel impulse response rather than the channel response itself by skillfully exploiting...
In this paper we derive the optimal space-time power allocation scheme that minimizes the BER for MIMO fading channels when ideal channel state information (CSI) is available at the transmitter and receiver. We then show that this scheme achieves exponential diversity. Simulation results corroborating the theoretical analysis are then presented for MIMO Rician fading channels where we show that for...
In contrast to the outage analysis, the packet error rates (PERs) of two types of cooperative automatic retransmission request (ARQ) protocols with opportunistic selective amplified-and-forward (OSAF) relaying are investigated from the perspective of the maximum likelihood sequence detection (MLSD). The results show that PERs with the threshold requirements derived from the outage analysis cannot...
Carrier aggregation (CA) is one of the key features for LTE-Advanced. By means of CA, two or more component carriers (CCs) can be aggregated to form a much wider transmission bandwidth up to 100 MHz in order to meet the IMT-Advanced requirements. With CA, it is possible to schedule a user equipment (UE) on multiple component carriers simultaneously. From radio resource management (RRM) perspective,...
In some harsh environment, wireless sensor networks without the sink are often deployed. In the network, the nodes just have limited energy and are easy to fail. In order to prevent the data loss due to the failure of nodes, each node disseminates its data to be stored at a subset of nodes in the network for preservation. However, each node just knows the information of its neighbors, and just has...
In recent years, the femtocell plays an important role in wireless networks not only for its spectrum reuse but also for its low power consumption. However, there exists several critical issues that need to be investigated, especially for the interferences between the macrocells and the femtocells. Two major access policies are considered in the femtocell network, including the closed access mode...
Femtocells are expected as the surest way to increase the system capacity with higher-quality links and more spatial reuse in future networks. In spite of their great potential, the system capacity is highly susceptible to network density because a large portion of users are exposed to inter-cell interference (ICI). In this work, we proposed a dynamic interference avoidance scheme in densely deployed...
Restoring connectivity subjected to the failure of mobile node(s) is an important research challenge in mobile ad hoc networks. To achieve this objective, a Connectivity Restoration Strategy (CRS) is developed, aiming at restoring the connectivity of mobile network whenever it is partitioned from multiple simultaneous node failures. The proposed strategy is fully distributed and requires only local...
We consider several fading channel models for which we aim to maximize ergodic capacity assuming that channel state information (CSI) is available at both the receiver and the transmitter. We characterize the optimal power allocation structure in the single-input-single-output (SISO), multiple-input- single-output (MISO), and multiple-input-multiple-output (MIMO) models subject to both long-term and...
This paper addresses the linear processing issues for two way non-regenerative MIMO relay systems with multiple antennas at each node. Based on theoretical derivation, we first propose an optimal joint iterative linear processing scheme for the relay node and receiving source nodes, aiming to minimize the total mean squared error (MSE). The convergence of this iterative algorithm is proved in terms...
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