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We consider the distributed channel allocation problem in an asymmetrical opportunistic spectrum access (OSA) system where each secondary user possibly has different channel reward even in the same channel due to geographic dispersion. We formulate this problem as a Gale-Shapley stable theorem using game theory to optimize the sum reward of all secondary users. It is challenging to achieve the stable...
Cooperative spectrum sensing has been proposed to significantly improve spectrum sensing accuracy by taking advantage of the cooperation among multiple secondary users (SUs). Most of existing work assumes that all SUs have the same SNR values of primary users' signal while the difference of SNR values among SUs, although it is very common in practice, is largely ignored. In this paper, we investigate...
In this paper we investigate a cooperative jamming (CJ) strategy based Stackelberg security game to improve physical layer security over multiuser OFDMA networks. Each source node tries to deliver messages to its intended destination node securely in the presence of a passive eavesdropper. Fortunately, these node pairs can resort to a friendly jammer to enhance their communication. But the jamming...
Spectrum sensing is a key feasible technology for cognitive radio (CR). Sensing time is an important sensing parameter which brings about a sensing-throughput tradeoff. In this paper, based on soft decision schemes, we investigate the sensing-throughput tradeoff problem and analyze the impact of different system parameters on the optimal sensing time for cooperative spectrum sensing. Simulation results...
In this paper, a two-way relay channel is considered, where two sources transmit information to each other with the help of a half-duplex decode-and-forward (DF) relay. We investigate the energy efficiency (EE) for the DF two-way relay transmission (TWRT). The EE expression is derived first and the properties of the EE are then analyzed. An novel algorithm is proposed to find the maximal EE under...
In this paper, a resource allocation algorithm is proposed for different quality of service (QoS) guarantee, fair transmission and high data rate in orthogonal frequency division multiple access (OFDMA) and wireless local area network (WLAN) integrated system. First, different QoS requirements are converted into different rate requests for simplifying the optimization problem. Second, the sub-channels...
This paper investigates the resource allocation problem for multiple description coding (MDC) multicast in OFDM-based cognitive radio (CR) systems, where secondary users (SUs) share the primary spectrum under the interference constraints of primary users (PUs). The previous multicast model is usually based on the full buffer traffic in which there are sufficient data for multicast groups (MGs) to...
Spectrums are heterogeneous, especially from the aspect of their central frequency. According to signal propagation properties, low-frequency spectrum generally has lower path loss, thus longer transmission range, compared with high-frequency spectrum. Cellular operators with different targeted cell size will have different preferences for spectrums with different frequencies. Furthermore, the transmission...
Traditional physical layer security methods, such as artificial noise, commonly require that the sender has more antennas than that of the receivers, which is not practical in the multicasting system. To solve this problem, a multicarrier-based physical layer security scheme for the multicast systems is proposed, which takes the advantage of both space and frequency domain to form a relatively virtual...
Multiuser voice conferencing platforms are more and more popular. Internet bandwidth is becoming very accessible, what makes voice over IP used on an everyday basis. Being able to communicate with multiple people at the same time can be beneficial, but on the other hand increases the need of coordination mechanisms. Determining a moderation scheme which is fair and efficient is not a trivial problem...
Service fairness of traffic with different granularities in elastic optical networks is addressed and correspondingly a fairness-aware spectrum allocation scheme is proposed. Simulation results imply that it achieves service fairness without significant blocking performance deterioration.
Wireless Sensor Networks (WSN) consists of small sensor devices with sensing, processing and communication capabilities. Sensor nodes are operated by batteries. As the replacement of these batteries are not practical, this network is very much energy sensitive. Resource coordination is an important issue to make this system energy efficient. Sensor nodes can be applied in various applications. Object...
In this paper, we focus on resource allocation for distributed broadband heterogeneous networks. Considering the fairness among different users, using the game-theoretic diagram, a fair resource allocation scheme is proposed first under each mobile user's minimal rate constraint. Then, an optimal power allocation algorithm is derived based on the Lagrange optimization method. To further improve the...
The cognitive radio (CR) seems to be an optimal transmission system which can achieve higher throughput efficiency by exploiting the best areas of the radio spectrum. However, the CR should obey the interference limit in order to protect the transmission of the primary radios (PRs). In this paper, we introduce an innovative channel allocation scheme that minimizes the interference caused by the transmission...
So far open source software has been developed for several decades. Linux has gradually become one of the major operating systems. The issue that Windows application migration can be migrate to Linux is raised. However, there is great difference in the implementation mechanism between Windows and Linux. In this research, we try to build an middle layer which between application and operating system...
Social collaboration scenarios, such as sharing resources between friends, are becoming increasingly prevalent in recent years. An example of this new paradigm is Social Cloud Computing, which aims at leveraging existing digital relationships within social networks for the exchange of resources among users and user communities. Due to their complexity, such platforms and systems have to be carefully...
Radio resource management in multi-user LTE networks is considered in this paper. Subject to a transmission power constraint, genetic algorithm is firstly investigated to optimize the system transmission rate. However, result shows genetic algorithm has the flaws of slow convergence rate and cannot reach to the theoretical maximum transmission rate. Aiming at this point, ant colony algorithm (ACA)...
We propose a power saving localization scheme that reduces redundant localization packets by considering distances from neighbor sensor nodes and a maximum localization error of a sensor node while maintaing localization error at the same level as the conventional scheme. In our proposed scheme, we set the threshold based on the overlapped area and each sensor node inhibits transmitting its localization...
This paper proposes a resource allocation scheme for enhanced inter-cell interference coordination (eICIC) in heterogeneous networks. In the eICIC system, the macro eNBs will stop data transmission in almost blank subframes (ABSs), where the UEs in small cells can be protected. The proposed scheme takes into account both the number of the ABSs configured at the macro eNBs and the UE partition scheme...
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