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In this paper, a new dynamic access scheme is proposed which differentiates secondary users (SUs) on the basis of their type: voice or data call. A voice call is preferred over a data call in the paper. If a primary user (PU) wants to access the spectrum, then a SU with data call will be placed in buffer. If no SU with data call is accessing the spectrum, then one of the SU with voice call will give...
The concept of small cells such as femtocells has been regarded as a promising solution to overcome the indoor coverage problem and deal with the growth of traffic within macrocells. However, the unpredictable deployment pattern of such cells makes centralized network planning impractical and requires more efficient interference management and distributed spectrum planning schemes to realize the benefit...
This paper studies the economic interactions between Secondary Users and Primary Operators in a Cognitive Radio Network scenario. Secondary Users transmit their traffic, eventually splitting it over multiple available frequency spectra, each owned by an independent primary network operator. Users are charged a fixed price per unit of bandwidth used, and face spectrum access costs. The transmission...
This paper presents the first analytical study of optimal investment and pricing decisions of a cognitive mobile virtual network operator (C-MVNO) under spectrum supply uncertainty. Compared with a traditional MVNO who only obtains spectrum by long-term leasing contracts, a C-MVNO can acquire short-term spectrum by both sensing the empty "spectrum holes" of licensed bands and dynamically...
We consider a cognitive network where the secondary users generate voice traffic and search for sharing opportunities over the TV spectrum. From the cognitive network perspective the TV bands can be idle, occupied or acceptable. A band is classified as acceptable when the TV signal is present but the secondary users can still share the band by lowering their transmission power. Therefore, the acceptable...
Providing the required quality of service (QoS) for clients in a wireless mesh network (WMN) is a challenging task. This is due to the complex architecture of the WMN and unpredictable behavior of the wireless links and the intermediate nodes. This can be alleviated by introducing a cognitive mechanism within the WMN. In this paper, a WMN is developed, where the data traffic is forwarded in a cognitive...
In this paper we investigate the performance of a cognitive personal area network (CPAN) with round robin service where each node is allowed to transmit a batch of up to ?? packets in one transmission cycle. In order to contribute to cooperative sensing (and thus support the operation of the CPAN), each node need to perform sensing duty, the duration of which is proportional to the number of packets...
Cognitive Radio (CR) has been studied recently as an enabling technology for dynamic spectrum access. In this paper, the concept of Bandwidth Time Cube (BTC) is defined with a three dimensional space for maximizing spectrum usage to model radio spectrum management. In order to utilize unused frequencies, a DSHR (Dynamic Spectrum Heuristic Replacement) algorithm is proposed for a multi-hop CR networks...
The cognitive framework, which fosters an efficient use of the channel resource by granting access to smart and adaptive terminals, has been recently integrated with the cooperative paradigm. Accordingly, following a spectrum-leasing approach, licensed (primary) users may let unlicensed (secondary) users access the owned bandwidth in exchange for an increased performance via cooperation. Nevertheless,...
In this work, we consider a multi-hop cognitive radio network with multiple flows. The challenges induced by the random behaviors of the primary users are investigated in a stochastic network utility maximization framework. To fully utilize the scarce network resource, we propose an optimal traffic splitting scheme for each source node to explore multiple paths effectively. In addition, the algorithm...
The paper investigates on fairness of utilities between uplink and downlink traffic flows in IEEE 802.11 Wireless Local Area Networks (WLAN) with an infrastructure mode. We propose a cognitive resource allocation scheme to tackle the fairness problem. The proposed scheme is cognitive by using neural networks to on-line learn the nonlinear function between the adopted Medium Access Control (MAC) parameters...
Cognitive radio (CR) improves utilization of the overall radio spectrum through dynamic adaptation to local spectrum availability. In CR networks, unlicensed or secondary users (SUs) may operate in underutilized spectrum owned by the licensed or primary users (PUs) conditional upon PU encountering acceptable interference levels. A cognitive wireless ad hoc network (CWAN) is a multihop self-organized...
Cognitive radio (CR) has the potential to substantially improve the system capacity and adaptability of wireless mesh network (WMN). In this paper we investigate the achievable performance gain of cognitive wireless mesh network (CWMN), in which all nodes are equipped with CRs, by jointly optimizing spectrum allocation, routing and time scheduling. The formulated optimization problem aims to minimize...
In this paper, we investigate the issues of survivability and efficiency in a heterogeneous mobile ad hoc network (MANET) and Sensor network as a combined network where the communications is achieved using a mixed MANET and Sensor Network, referred to as SMANET for supporting mission critical applications. Using the cluster managed SMANET where, heterogeneous nodes with different capabilities and...
To investigate how to support user communication sessions in cognitive radio (CR), the radio technology should jointly perform power control, scheduling, and flow routing, which are generated by a multi-hop wireless network. With the adjustments of migrating nodes to neighboring nodes, a bandwidth footprint tree (BFT) is defined in this paper. Based on reducing hot spots approach, the distributed...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
IEEE P1900.4 is an emerging standard for optimized radio resource utilization where cognitive radio technologies are used for efficient spectrum utilization. In this paper, we design and implement a cognitive wireless network system based on open documents of IEEE P1900.4, and evaluate its performance using UDP streaming and HTTP download. Our experiments show interesting results that total network...
This paper is devoted to the development of cognitive routing techniques for a wireless ad hoc network in order to improve scalability and effectively the supportable capacity. Different routing strategies are examined and a novel capacity-based routing strategy is emphasized. Its capacity performance is evaluated using conventional shortest path routing as a benchmark. It shows the proposed capacity-based...
Cognitive radio presents a new approach to wireless spectrum utilization and management. In this work, the potential performance improvement gained by applying cognitive radio to multiple-provider wireless systems is investigated. It is shown that virtual wireless networks can be created, utilizing only the residual wasted bandwidth of the primary service providers. These virtual networks are able...
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