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Due to the dynamic interruptions from the primary users (PUs), the secondary user (SU) (i.e., cognitive radio) network is highly dynamic with fast varying radio resources. Once a PU requests to occupy the licensed spectrum, all of affected SUs (i.e., those SUs who opportunistically access the licensed spectrum) are mandated to immediately terminate the spectrum usage and switch their data transmissions...
This paper proposes a joint power and resource allocation methodology, by using a node-centric scheme. Each node estimates the throughput Θ(ts) and tunes the proposed path-aware energy conservation mechanism, according to requested delay constrained resources, as well as the bandwidth resources that the associated channels can handle in time. The combined power and frequency bandwidth allocation scheme...
This paper proposes a spectrum access method based on the capacity utility maximization in wireless cognitive mesh networks. By taking into account the inactivity probability of the primary users, the spectrum sensing time, the probability of false alarm and the channel usage of the surrounding secondary users, a capacity utility function is formed. Through maximizing the capacity utility function,...
In this paper, we propose a joint channel allocation and multicast routing scheme for a multihop cognitive radio network. Our scheme can react to the dynamic change of channel availability. It can maximize the multicast throughput by jointly performing channel allocation and multicast routing. We first model the activities of the primary users, channel availability and the interference among the secondary...
In this paper, we propose a novel routing protocol which is integrated with channel assignment for multi-channel multi-hop wireless ad hoc networks. In such a network, each node is equipped with three transceivers. One is always tuned on a control channel which is responsible for control and broadcast messages, and the other two perform as transmitter and receiver respectively for traffic flows on...
Recently, the variable channel-width (VW) scheme was proposed to improve the performance of WLANs. Cooperative channel allocation has been studied in some existing literature under the assumption that the traffic demands of cooperative access points (APs) are constant. In fact, the traffic demands may vary when the corresponding stations change their AP association decisions. Hence, this work jointly...
Recently, Orthogonal Frequency Division Multiple Access (OFDMA) transmission technique is applied widely in wireless networks because of its high transmission capacity. The IEEE 802.16 standard has also adopted the OFDMA as its access technique. However, the problem of bandwidth resource allocation in time and frequency is essential for efficient utilization of OFDMA system. In this paper, we proposed...
Using network coding in a wireless network can potentially improve the network throughput. On the other hand, it increases the complexity of resource allocations as the quality of one transmission is often affected by the link conditions of the transmitter node to multiple destination nodes. In this paper we consider a multi-channel wireless network with a star topology. Network coding is used for...
This paper analyzes the possibility to introduce a WiFi type of secondary network containing multiple secondary access points (SAPs) in TV bands. In particular, the analysis investigates the limitations of TV whitespace (TVWS) usage imposed by the aggregate interference of the secondary users towards the primary and secondary system, assuming different levels of penetration of the TVWS-operating technology...
In this paper, we focus on the bandwidth allocation issue in wireless access networks, which are made up of Ethernet Passive Optical Network (EPON) and Worldwide Interoperability for Microwave Access (WiMAX) networks, i.e., Fiber-Wire (FiWi) networks. Since the bandwidth allocation scheme largely determines the performance of the entire wireless access network, in the past decades, researchers have...
Cloud robotics is currently driving interest in both academia and industry, since it would allow robots to off-load computation intensive tasks, combine with multiple robots and even download new skills. Bandwidth allocation is the fundamental and dominant task for resource sharing among users in cloud robotics. However, many technical challenges are still outstanding, since incast congestion happens...
An efficient scheduling algorithm has been proposed for upstream bandwidth allocation in OFDMA PON systems to support differentiated services. Simulation result illustrates that the proposed algorithm obtains high throughput performance and channel utility.
Current high-performance capacity systems run hundreds of applications concurrently sharing the same network resources. In this scenario, system throughput and hence system utilization is significantly affected by inter-application contention. Quality-of-service (QoS) mechanisms are traditionally used in the Internet to provide different levels of performance guarantees. However, we have not found...
Cognitive radio (CR) is an emerging technique to improve the utilization of radio frequency spectrum in wireless communication networks. In this paper, we consider the problem of throughput maximization of spectrum allocation in cognitive radio networks. Furthermore, with increasing power level of secondary transmitters, primary receivers are affected by interference and go under outage. Therefore,...
Traffic load in the aggregate class of DiffServ network varies dynamically. However, when the traffic load proportion of different aggregate classes is not equal to the assigned weight proportion in the scheduling algorithm, such as the WFQ algorithm, the packets in different aggregate classes will receive unfair treatment, even though these classes have the same priority. Hence, research on fairness-oriented...
Many papers focus on how to provide high performance for on-chip network. However, fewer papers have discussed fair resource allocation. In fact, global unfairness problem does exist in a network even if locally fair arbitration is adopted. In this paper, we propose Group Allocation to solve global unfairness problem. By controlling the timing to assert the allocation request, Group Allocation changes...
In this paper, we consider the channel allocation problem for throughput maximization in cognitive radio networks with hardware-constrained secondary users. Specifically, we assume that secondary users exploit spectrum holes on a set of channels where each secondary user can use at most one available channel for communication. We develop two channel assignment algorithms that can efficiently utilize...
Femtocell network is an efficient configuration to improve coverage and quality of service (QoS) in cellular networks. However, due to dense deployment, users in a femtocell may be interfered by the base stations nearby, resulting in a deteriorated throughput of the femtocell. In this paper, we investigate the resource allocation problem targeting at max-min throughput of the femtocells. Under the...
For reducing the channel switching frequency due to uncertain and frequent primary users' interruptions, we design a nonparametric channel allocation algorithm which can effectively manage the spectrum resources in distributed cognitive radio networks and serve for delay-sensitive data traffics. In the proposed algorithm, an infinite Gaussian mixture model is used to get the posterior decision from...
Channel allocation for a three-node cooperative cognitive radio network exploiting amplify-and-forward protocol (AF) is investigated in this paper. An optimal and a suboptimal channel allocation method were proposed in this paper. The optimal method is presented by picking the combination of channels that maximizes the system throughput. Comparing with the optimal method, the suboptimal algorithm...
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