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78
Cognitive network interference
- IEEE J. Sel. Areas Commun
, 2011
"... Abstract—Opportunistic spectrum access creates the opening of under-utilized portions of the licensed spectrum for reuse, provided that the transmissions of secondary radios do not cause harmful interference to primary users. Such a system would require secondary users to be cognitive—they must accu ..."
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Cited by 31 (3 self)
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Abstract—Opportunistic spectrum access creates the opening of under-utilized portions of the licensed spectrum for reuse, provided that the transmissions of secondary radios do not cause harmful interference to primary users. Such a system would require secondary users to be cognitive—they must accurately detect and rapidly react to varying spectrum usage. Therefore, it is important to characterize the effect of cognitive network interference due to such secondary spectrum reuse. In this paper, we propose a new statistical model for aggregate interference of a cognitive network, which accounts for the sensing procedure, secondary spatial reuse protocol, and environment-dependent conditions such as path loss, shadowing, and channel fading. We first derive the characteristic function and cumulants of the cognitive network interference at a primary user. Using the theory of truncated-stable distributions, we then develop the statistical model for the cognitive network interference. We further extend this model to include the effect of power control and demonstrate the use of our model in evaluating the system performance of cognitive networks. Numerical results show the effectiveness of our model for capturing the statistical behavior of the cognitive network interference. This work provides essential understanding of interference for successful deployment of future cognitive networks. Index Terms—Opportunistic spectrum access, cognitive ra-dio, cognitive network interference, detection-and-avoidance, truncated-stable distribution. I.
1 Protocol Design and Throughput Analysis for Multi-user Cognitive Cooperative Systems
, 2009
"... This paper deals with protocol design for cognitive cooperative systems with many secondary users. In contrast with previous cognitive configurations, the channel model considered assumes a cluster of secondary users which perform both a sensing process for transmitting opportunities and can relay d ..."
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Cited by 28 (3 self)
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This paper deals with protocol design for cognitive cooperative systems with many secondary users. In contrast with previous cognitive configurations, the channel model considered assumes a cluster of secondary users which perform both a sensing process for transmitting opportunities and can relay data for the primary user. Appropriate relaying improves the throughput of the primary users and can increase the transmission opportunities for the cognitive users. Based on different multi-access protocols, the schemes investigated enable relaying either between the primary user and a selected secondary user or between two selected secondary users. This collaboration can be a simple distributed multipleinput single-output transmission of the primary data or a simultaneous transmission of primary and secondary data using dirty-paper coding (DPC). The parametrization of DPC as well as its combination with opportunistic relay selection yields an interesting trade-off between the primary and the secondary performance which is investigated by theoretical and simulation results under the perspective of a desired primary throughput. The proposed protocols are studied from a networking point of view and the stable throughput for primary and secondary users is derived based on the principles of queueing theory. Index Terms analysis.
Efficient Resource Allocation with Flexible Channel Cooperation in OFDMA Cognitive Radio Networks
"... Abstract—Recently, a cooperative paradigm for single-channel cognitive radio networks has been advocated, where primary users can leverage secondary users to relay their traffic. However, it is not clear how such cooperation can be exploited in multi-channel networks effectively. Conventional cooper ..."
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Cited by 22 (1 self)
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Abstract—Recently, a cooperative paradigm for single-channel cognitive radio networks has been advocated, where primary users can leverage secondary users to relay their traffic. However, it is not clear how such cooperation can be exploited in multi-channel networks effectively. Conventional cooperation entails that data on one channel has to be relayed on exactly the same channel, which is inefficient in multi-channel networks with channel and user diversity. Moreover, the selfishness of users complicates the critical resource allocation problem, as both parties target at maximizing their own utility. This work represents the first attempt to address these challenges. We propose FLEC, a novel design of flexible channel cooperation. It allows secondary users to freely optimize the use of channels for transmitting primary data along with their own data, in order to maximize performance. Further, we formulate a unifying optimization framework based on Nash Bargaining Solutions to fairly and efficiently address resource allocation between primary and secondary networks, in both decentralized and centralized settings. We present an optimal distributed algorithm and sub-optimal centralized heuristics, and verify their effectiveness via realistic simulations.
Competition with dynamic spectrum leasing,”
, 2009
"... Abstract-Dynamic spectrum leasing can greatly enhance the spectrum efficiency and encourage more flexible services in the spectrum market. This paper presents a detailed analytical study of the strategic interactions of two competing secondary network operators (duopoly) who need to make optimal in ..."
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Cited by 19 (5 self)
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Abstract-Dynamic spectrum leasing can greatly enhance the spectrum efficiency and encourage more flexible services in the spectrum market. This paper presents a detailed analytical study of the strategic interactions of two competing secondary network operators (duopoly) who need to make optimal investment (leasing) and pricing decisions while taking secondary endusers' heterogeneous wireless characteristics into consideration. The operators need to determine how much to lease from the spectrum owner, and compete to sell the spectrum to secondary users to maximize their individual profits. We model the system as a three-stage multi-leader dynamic game. Both the operators' equilibrium investment and pricing decisions turn out to have nice threshold properties. Each secondary user receives a fair equilibrium resource allocation that only depends on the leasing cost of the operators and is independent of other users' channel conditions and transmission powers. To further understand the impact of competition, we compare the duopoly equilibrium result with the coordinated case where the two operators cooperate to maximize the total profit. We show that the Price of Anarchy of the two operators' total profit is 82% with symmetric leasing cost, i.e., the maximum loss of the total profit due to competition is no larger than 18%. We also show that competition always leads to better payoffs for users compared with the coordinated case.
Decentralized Cognitive Radio Control based on Inference from Primary Link Control Information 1
"... This work on cognitive radio access ventures beyond the more traditional “listen-before-talk ” paradigm that underlies many cognitive radio access proposals. We exploit the bi-directional interaction of most primary communication links. By intelligently controlling their access parameters based on t ..."
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Cited by 16 (0 self)
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This work on cognitive radio access ventures beyond the more traditional “listen-before-talk ” paradigm that underlies many cognitive radio access proposals. We exploit the bi-directional interaction of most primary communication links. By intelligently controlling their access parameters based on the inference from observed link control signals of primary user (PU) communications, cognitive secondary users (SUs) can achieve higher spectrum efficiency while limiting their interference to the PU network. In one specific implementation, we let the SUs listen to the PU’s feedback channel to assess their own interference on the primary receiver (PU-Rx), and adjust radio power accordingly to satisfy the PU’s interference constraint. We propose a discounted distributed power control algorithm to achieve non-intrusive secondary spectrum access without a centralized controller or active PU cooperation, and study analytically its convergence property. We show that the link control feedback information inherent in many two-way primary systems can be used as important reference signal among multiple SU pairs to distributively achieve a joint performance assurance for primary receiver’s quality of service. Index Terms Wireless communications, inference for opportunistic spectrum access, dynamic spectrum access control, distributed algorithm, cognitive radio networks. I.
Opportunistic cooperation in cognitive femtocell networks
- the IEEE Journal on Selected Areas in Communications
"... All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately. ..."
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Cited by 15 (2 self)
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All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
Throughput and Delay Bounds for Cognitive Transmissions
- In Proc. Med-Hoc-Net’08
, 2008
"... Abstract Cognitive networks are based on agile and opportunistic use of spectrum resources. This work focuses on those network scenarios where primary or licensed users coexist with secondary or unlicensed ones. Secondary users opportunistically access the shared resources whenever vacant, with the ..."
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Cited by 10 (0 self)
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Abstract Cognitive networks are based on agile and opportunistic use of spectrum resources. This work focuses on those network scenarios where primary or licensed users coexist with secondary or unlicensed ones. Secondary users opportunistically access the shared resources whenever vacant, with the strict constraint of being invisible to primary users. We derive here analytical bounds on throughput and transmission delay of secondary users under different assumptions on secondary and primary users traffic statistics, and we comment on the use of the proposed models to dimension secondary transmissions. 1
Exploiting mimo antennas in cooperative cognitive radio networks
- in Proc. IEEE INFOCOM
, 2011
"... Abstract—Recently, a new paradigm for cognitive radio net-works has been advocated, where primary users (PUs) recruit some secondary users (SUs) to cooperatively relay the primary traffic. However, all existing work on such cooperative cognitive radio networks (CCRNs) operate in the temporal domain. ..."
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Cited by 9 (1 self)
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Abstract—Recently, a new paradigm for cognitive radio net-works has been advocated, where primary users (PUs) recruit some secondary users (SUs) to cooperatively relay the primary traffic. However, all existing work on such cooperative cognitive radio networks (CCRNs) operate in the temporal domain. The PU needs to give out a dedicated portion of channel access time to the SUs for transmitting the secondary data in exchange for the SUs ’ cooperation, which limits the performance of both PUs and SUs. On the other hand, Multiple Input Multiple Output (MIMO) enables transmission of multiple independent data streams and suppression of interference via beam-forming in the spatial domain over MIMO antenna elements to provide significant performance gains. Researches have not yet explored how to take advantage of the MIMO technique in CCRNs. In this paper, we propose a novel MIMO-CCRN framework, which enables the SUs to utilize the capability provided by the MIMO to cooperatively relay the traffic for the PUs while concurrently accessing the same channel to transmit their own traffic. We design the MIMO-CCRN architecture by considering both the temporal and spatial domains to improve spectrum efficiency. Further we provide theoretical analysis for the primary and secondary transmission rate under MIMO cooperation and then formulate an optimization model based on a Stackelberg game to maximize the utilities of PUs and SUs. Evaluation results show that both primary and secondary users achieve higher utility by leveraging MIMO spatial cooperation in MIMO-CCRN than with conventional schemes. I.
Cognitive code-division links with blind primary-system identification
- IEEE Trans. Wireless Commun
"... Abstract—We consider the problem of cognitive code-division channelization (simultaneous power and code-channel allocation) for secondary transmission links co-existing with an unknown primary code-division multiple-access (CDMA) system. We first develop a blind primary-user identification scheme to ..."
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Cited by 8 (6 self)
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Abstract—We consider the problem of cognitive code-division channelization (simultaneous power and code-channel allocation) for secondary transmission links co-existing with an unknown primary code-division multiple-access (CDMA) system. We first develop a blind primary-user identification scheme to detect the binary code sequences (signatures) utilized by primary users. To create a secondary link we propose two alternative procedures –one of moderate and one of low computational complexity – that optimize the secondary transmitting power and binary codechannel assignment in accordance with the detected primary code channels to avoid “harmful ” interference. At the same time, the optimization procedures guarantee that the signalto-interference-plus-noise ratio (SINR) at the output of the maximum SINR linear secondary receiver is no less than a certain threshold to meet secondary transmission quality of service (QoS) requirements. The extension of the channelization problem to multiple secondary links is also investigated. Simulation studies presented herein illustrate the theoretical developments. Index Terms—Blind user identification, code-channel allocation, code-division multiple-access, cognitive radio, dynamic spectrum access, power allocation, signal-to-interference-plusnoise ratio. I.
Optimal scheduling in cooperate-to-join cognitive radio networks,”
- in Proceedings of the IEEE INFOCOM,
, 2011
"... Abstract-Optimal transmission scheduling in wireless cognitive networks is considered under the spectrum leasing model. We propose a cooperative scheme in which secondary nodes share the time slot with primary nodes in return for cooperation. Cooperation is feasible only if the system's perfor ..."
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Cited by 8 (1 self)
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Abstract-Optimal transmission scheduling in wireless cognitive networks is considered under the spectrum leasing model. We propose a cooperative scheme in which secondary nodes share the time slot with primary nodes in return for cooperation. Cooperation is feasible only if the system's performance is improved over the non-cooperative case. First, we investigate a scenario where secondary users are interested in immediate rewards. Then, we formulate another problem where the secondary users are guaranteed a portion of the primary utility, on a long term basis, in return for cooperation. In both scenarios, our proposed schemes are shown to outperform non-cooperative scheduling schemes, in terms of both individual and total expected utility, for a given set of feasible constraints. Based on Lyapunov Optimization techniques, we show that our schemes are arbitrarily close to the optimal performance at the price of reduced convergence rate.
