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## Dynamic Cooperative Secondary Access in Hierarchical Spectrum Sharing Networks

### Citations

1894 |
Markov Decision Processes: Discrete Stochastic Dynamic Programming
- Puterman
- 1994
(Show Context)
Citation Context ... define the cost of secondary access as the combination of the cost of cooperation and the cost of additional packet delay, and define dynamic cooperative secondary access schemes that aim at minimizing the long-run average cost. We provide a Markov Decision Process (MDP) formulation to derive optimal access schemes when the load and the network parameters are known for the secondary system, and evaluate the performance of reinforcement learning for the cases when this knowledge is not available. The MDP framework and its variations such as constrained MDP and Partially Observable MDP (POMDP) [25] have been used extensively for optimizing control strategies in discrete time stochastic systems in general. In the area of spectrum sharing networks with opportunistic secondary access MDP has been used to design sensing and access strategies for the SUs, when the primary traffic can be modeled with some known stochastic processes [2][3][5][6]. Reinforcement learning techniques, such as Q-learning [26] and R-learning [27] provide online optimization tools that can solve MDPs it2 eratively without a priori knowledge of the state transition probabilities, and therefore, has been used for secon... |

448 | A survey of dynamic spectrum access
- Zhao, Sadler
- 2007
(Show Context)
Citation Context ...trum sharing among users of different networks is a promising solution to improve the spectrum efficiency, and thus to alleviate the spectrum shortage problem caused by the rapidly growing demand for wireless applications and services. Under hierarchical spectrum sharing the higher priority, primary users (PUs) have performance guarantees, whereas the secondary, low priority users (SUs) need to be cognitive, and adjust their access strategies so that the primary performance does not degrade. One traditional paradigm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division ... |

154 | The role of exploration in learning control
- Thrun
(Show Context)
Citation Context ...b). The above R-learning algorithm runs similarly in the fullstate and the reduced-state scenarios. The main difference is that (Np + 1) × (Ns + 1) R-factors need to be learned in the former case, whereas only 2(Ns + 1) ones in the latter one. For R-learning in the considered infinite buffer system the state space is extended dynamically according to the maximum experienced queue lengths. We apply R-learning algorithm with semi-uniform exploration, with constant αt. Other exploratory methods, like Boltzmann exploration, uncertainty estimation (UE) exploration are presented and compared in [27][34]. While the convergence of R-learning to the optimal value is not proved, the detailed evaluations show that R-learning finds near optimal solutions in most scenarios [27]. VI. Case Study In this section, we compare the optimal sequential decision (OSD) with the opportunistic (OPP), and the cooperative (COOP) schemes, as well as with optimal random cooperation (ORC), that is, random cooperation with optimal stateindependent cooperation probability, that minimizes the longrun average cost. For OSD we obtain the optimal sequential decision policy by solving the LP in (10), and perform simulation... |

137 | Joint design and separation principle for opportunistic spectrum access in the presence of sensing errors,”
- Chen, Zhao, et al.
- 2008
(Show Context)
Citation Context ... to improve the spectrum efficiency, and thus to alleviate the spectrum shortage problem caused by the rapidly growing demand for wireless applications and services. Under hierarchical spectrum sharing the higher priority, primary users (PUs) have performance guarantees, whereas the secondary, low priority users (SUs) need to be cognitive, and adjust their access strategies so that the primary performance does not degrade. One traditional paradigm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation betwee... |

129 | Average reward reinforcement learning: Foundations, algorithms, and empirical results.
- Mahadevan
- 1996
(Show Context)
Citation Context ...reinforcement learning for the cases when this knowledge is not available. The MDP framework and its variations such as constrained MDP and Partially Observable MDP (POMDP) [25] have been used extensively for optimizing control strategies in discrete time stochastic systems in general. In the area of spectrum sharing networks with opportunistic secondary access MDP has been used to design sensing and access strategies for the SUs, when the primary traffic can be modeled with some known stochastic processes [2][3][5][6]. Reinforcement learning techniques, such as Q-learning [26] and R-learning [27] provide online optimization tools that can solve MDPs it2 eratively without a priori knowledge of the state transition probabilities, and therefore, has been used for secondary access or interference control design, when the stochastic behavior of the primary system, or of the other interfering secondary systems are not known a priori [4][6][7]. In this paper we consider a primary and a secondary node pair, both with dynamic traffic and unreliable transmission channel. The SU aims at trading off the cost of cooperative relaying and the increased delay of opportunistic transmission. The main c... |

109 |
Dynamic power allocation and routing for satellite and wireless networks with time varing channels”,
- Neely
- 2003
(Show Context)
Citation Context ... not received successfully are retransmitted. We assume that ACK/NACK messages from the PR and the SR do not get lost. The resulting queuing networks for opportunistic and cooperative spectrum sharing are shown in Fig. 1(a) and (b), respectively. We can see that in both cases the primary and the secondary queues are coupled, more precisely, the service rate of the ST depends on the status of the queue at the PT. III. The Stable-Throughput Region Let us first evaluate the stable-throughput regions of the considered spectrum sharing methods. We follow the notion of strong stability given in [28][29], for slotted systems with time varying service process. To define strong stability, let us denote the queue length at the beginning of a time slot n as Q(n), the number of arrivals in time slot n as A(n), and the service rate as B(n). We assume that arrivals happen at the end of the time slot, and can be served only in the following slot. Then, the queue evolves, as: Q(n + 1) = max[Q(n) − B(n), 0] + A(n). Definition 1. The queue is strongly stable, if [28]: lim sup N→∞ 1 N N∑ n=1 E[Q(n)] < ∞. (1) That is, the queue is strongly stable, if it has a bounded average queue length. A network of que... |

73 | Stable Throughput of Cognitive Radios With and Without Relaying Capability
- Simeone, Bar-Ness, et al.
- 2007
(Show Context)
Citation Context ..., or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in [21][22][23][24]. These works characterize the stable-throughput region under stochastic packet arrival and transmission processes, however, still assuming that the SUs always cooperate. In this paper we formulate the dilemma of the secondary user that needs to transmit a stream of randomly arriving packets. As the primary performance needs to be guaranteed, the SU may have significant cost of cooperation, in terms of increased transmission power or very low probability of successful transmission. Therefore, under dynamic load, the SU may instead wait for idle time and transmit opportunistically. ... |

63 |
On the stability of interacting queues in a multiple-access system
- Rao, Ephremides
- 1988
(Show Context)
Citation Context ... < (1 − pc)qpd + pcqpc λs < qsd + pcqsc−qsd (1−pc)qpd+pcqpc λp } . Opportunistic and cooperative spectrum sharing are special cases of random cooperation with pc = 0 and pc = 1, respectively. As expected, SR is equivalent to SD when pc = 0, and to SC when pc = 1. Let us now evaluate the stable-throughput region of the sequential decision scheme, following the dominant system approach. We consider a system X to be a dominant system of Y , if the queue sizes in X are, at all times, at least as large as those in Y . The stable-throughput region of the dominant system X inner bounds that of Y [23][31]. By comparing the average service rate of PT in (2) with that in (4), and the average service rate of ST in (3) with that in (5), we get μpd ≤ μpc and μsd ≤ μsc. So for any sequential decision scheme Π, the primary and secondary service rates are bounded as μΠp ∈ [μpd, μpc] and μΠs ∈ [μsd, μsc]. Consequently, any sequential decision scheme stochastically dominates the opportunistic one, and is dominated by the cooperative one, that is, SD ⊆ SΠ ⊆ SC . Fig. 2 gives an example of the stable-throughput region. The shaded area shows the improvement achieved by cooperation, which is significant if ... |

32 |
Average cost optimal stationary policies in infinite state Markov Decision Processes with unbounded costs”,
- Sennott
- 1989
(Show Context)
Citation Context ...owever, the stability of Qp is not guaranteed. This proves the first part of Theorem 2. As the optimal policy Π∗ achieves the minimum average cost under given λp and λs, this cost has to be upper bounded by the average cost of the cooperation based spectrum sharing, that is, C(Π∗) ≤ C(ΠC). As C(ΠC) < ∞ within SC , C(Π∗) < ∞ within SC as well. C. The existence of optimal stationary policy We modeled the sequential decision with an infinite state MDP with unbounded costs and finite action set. We prove the existence of a stationary policy that is average cost optimal, building on the results of [33]. Following [33], let us introduce a discount factor 0 < β < 1, and give the total expected discounted cost incurred by policy Π as: VΠ,β(i, j) = EΠ ⎡⎢⎢⎢⎢⎢⎣ ∞∑ n=1 βnc(sn, πn)|s1 = (i, j) ⎤⎥⎥⎥⎥⎥⎦ . Let Vβ(i, j) = infΠ VΠ,β(i, j) and hβ(i, j) = Vβ(i, j) − Vβ(0, 0). Proposition 2 specifies the conditions that must be satisfied for the average cost optimal stationary policy to exist. Proposition 2. There exists a stationary policy that is average cost optimal for the MDP〈S,A,A, p, c〉 if the following conditions are satisfied: 1) Vβ(i, j) is finite for all (i, j) and β; 2) There exists a nonnegati... |

27 | Protocol design and throughput analysis for multi-user cognitive cooperative systems
- Krikidis, Laneman, et al.
- 2009
(Show Context)
Citation Context ... space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in [21][22][23][24]. These works characterize the stable-throughput region under stochastic packet arrival and transmission processes, however, still assuming that the SUs always cooperate. In this paper we formulate the dilemma of the secondary user that needs to transmit a stream of randomly arriving packets. As the primary performance needs to be guaranteed, the SU may have significant cost of cooperation, in terms of increased transmission power or very low probability of successful transmission. Therefore, under dynamic load, the SU may instead wait for idle time and transmit opportunistically. Note... |

23 | Optimal Cognitive Access of Markovian Channels under Tight Collision Constraints,”
- Li
- 2011
(Show Context)
Citation Context ...te the spectrum shortage problem caused by the rapidly growing demand for wireless applications and services. Under hierarchical spectrum sharing the higher priority, primary users (PUs) have performance guarantees, whereas the secondary, low priority users (SUs) need to be cognitive, and adjust their access strategies so that the primary performance does not degrade. One traditional paradigm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficien... |

19 |
Cooperative decode-and-forward relaying for secondary spectrum access,”
- Han, Pandharipande, et al.
- 2009
(Show Context)
Citation Context ...adigm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is cons... |

19 |
Stable throughput tradeoffs in cognitive shared channels with cooperative relaying
- Kompella, Nguyen, et al.
- 2011
(Show Context)
Citation Context ...ce-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in [21][22][23][24]. These works characterize the stable-throughput region under stochastic packet arrival and transmission processes, however, still assuming that the SUs always cooperate. In this paper we formulate the dilemma of the secondary user that needs to transmit a stream of randomly arriving packets. As the primary performance needs to be guaranteed, the SU may have significant cost of cooperation, in terms of increased transmission power or very low probability of successful transmission. Therefore, under dynamic load, the SU may instead wait for idle time and transmit opportunistically. Note tha... |

14 |
Cooperative spectrum sharing protocol with secondary user selection,”
- Han, Tingand, et al.
- 2010
(Show Context)
Citation Context ...gm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is conside... |

11 |
Detection of spectral resources in cognitive radios using reinforcement learning,”
- Berthold, Schaar, et al.
- 2008
(Show Context)
Citation Context ...prove the spectrum efficiency, and thus to alleviate the spectrum shortage problem caused by the rapidly growing demand for wireless applications and services. Under hierarchical spectrum sharing the higher priority, primary users (PUs) have performance guarantees, whereas the secondary, low priority users (SUs) need to be cognitive, and adjust their access strategies so that the primary performance does not degrade. One traditional paradigm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the ... |

11 |
Distributed Q-Learning for Aggregated Interference Control in Cognitive Radio Networks,”
- Galindo-Serrano, Giupponi
- 2010
(Show Context)
Citation Context ... spectrum shortage problem caused by the rapidly growing demand for wireless applications and services. Under hierarchical spectrum sharing the higher priority, primary users (PUs) have performance guarantees, whereas the secondary, low priority users (SUs) need to be cognitive, and adjust their access strategies so that the primary performance does not degrade. One traditional paradigm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of ... |

10 | Contract-based cooperative spectrum sharing,” in
- Duan, Gao, et al.
- 2011
(Show Context)
Citation Context ...rum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum... |

10 |
Active cooperation between primary users and cognitive radio users in heterogeneous ad hoc networks,”
- Su, Matyjas, et al.
- 2012
(Show Context)
Citation Context ...pportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes... |

9 | Exploiting MIMO antennas in cooperative cognitive radio networks,” in
- Hua, Liu, et al.
- 2011
(Show Context)
Citation Context ...um sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in [21][22][23][24... |

7 |
Cooperative access in wireless networks: stable throughput and delay,”
- Rong, Ephremides
- 2012
(Show Context)
Citation Context ...17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in [21][22][23][24]. These works characterize the stable-throughput region under stochastic packet arrival and transmission processes, however, still assuming that the SUs always cooperate. In this paper we formulate the dilemma of the secondary user that needs to transmit a stream of randomly arriving packets. As the primary performance needs to be guaranteed, the SU may have significant cost of cooperation, in terms of increased transmission power or very low probability of successful transmission. Therefore, under dynamic load, the SU may instead wait for idle time and transmit opportunistically. Note that th... |

6 |
Spectrum leasing via cooperation with multiple primary users,”
- Elkourdi, Simeone
- 2012
(Show Context)
Citation Context ...al spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative ... |

6 | On the convergence to stationarity of birth-death processes,
- Coolen-Schrijner, Doorn
- 2001
(Show Context)
Citation Context ... processes with E[Ap(n)] = λp and E[As(n)] = λs, they are rate convergent with bounded second moment, that is, conditions 1 and 2 on the arrival processes hold. The service processes depend on the spectrum sharing scheme. For all schemes however Bp(n) and Bs(n) can take values 0 or 1, that is, condition 2 for the service processes holds. For all schemes, the service processes are either iid Bernoulli processes, or are controlled by the state of the queues, that in turn, when stable, can be described with ergodic discrete time birth-deaths processes, that converge monotonically to steady state [30]. (For example, under opportunistic spectrum sharing, the primary service process is an iid Bernoulli process with E[Bp(n)] = qpd, while the secondary service process is controlled by the primary queue length Qp, E[Bs(n)|Qp(n) = 0] = qpd and E[Bs(n)|Qp(n) > 0] = 0.) Consequently, the primary and secondary service processes are rate convergent, and thus, condition 1 for the service 4 processes is fulfilled as well, for all considered spectrum sharing schemes. Let us now find the λp, λs pairs when condition 3 holds. These arrival rate pairs give the stable-throughput region of the system. Consid... |

5 |
Cooperative cognitive radio networking using quadrature signaling,” in
- Cao, Cai
- 2012
(Show Context)
Citation Context ...acilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for ... |

4 | Adaptive joint scheduling of spectrum sensing and data transmission in cognitive radio networks,”
- Hoang, Liang, et al.
- 2010
(Show Context)
Citation Context ... improve the spectrum efficiency, and thus to alleviate the spectrum shortage problem caused by the rapidly growing demand for wireless applications and services. Under hierarchical spectrum sharing the higher priority, primary users (PUs) have performance guarantees, whereas the secondary, low priority users (SUs) need to be cognitive, and adjust their access strategies so that the primary performance does not degrade. One traditional paradigm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between t... |

3 |
A learning framework for cognitive interference networks with partial and noisy observations,”
- Levorato, Firouzabadi, et al.
- 2012
(Show Context)
Citation Context ...the spectrum shortage problem caused by the rapidly growing demand for wireless applications and services. Under hierarchical spectrum sharing the higher priority, primary users (PUs) have performance guarantees, whereas the secondary, low priority users (SUs) need to be cognitive, and adjust their access strategies so that the primary performance does not degrade. One traditional paradigm to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency ... |

3 |
Spectrum leasing to multiple cooperating secondary cellular networks,” in
- Yi, Zhang, et al.
- 2011
(Show Context)
Citation Context ...pectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spec... |

3 |
Cooperative OFDM relaying for opportunistic spectrum sharing: protocol design and resource allocation,”
- Lu, Gong, et al.
- 2012
(Show Context)
Citation Context ...tunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in ... |

3 | Throughput and delay scaling in supportive two-tier networks,”
- Gao, Zhang, et al.
- 2012
(Show Context)
Citation Context ...mitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in [21][22][23][24]. These works characterize the stable-throughput region under stochastic packet arrival and transmission processes, however, still assuming that the SUs always cooperate. In this paper we formulate the dilemma of the secondary user that needs to transmit a stream of randomly arriving packets. As the primary performance needs to be guaranteed, the SU may have significant cost of cooperation, in... |

2 |
On the gain of primary exclusion region and vertical cooperation in spectrum sharing wireless networks,”
- Wang, Fodor
- 2012
(Show Context)
Citation Context ...in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in [21][22][23][24]. These works characterize the stable-throughput region under stochastic packet arrival and transmission processes, however, still assuming that the SUs always cooperate. In this paper we formulate the dilemma of the secondary user that needs to transmit a stream of randomly arriving packets. As the primary performance needs to be guaranteed, the SU may have significant cost of cooperation, in terms o... |

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Multilevel modulation for cognitive multiaccess relay channel,”
- Krikidis
- 2010
(Show Context)
Citation Context ...to facilitate hierarchical spectrum sharing is opportunistic spectrum sharing [1], where SUs identify the timefrequency resources unused by the PUs [2][3][4], and exploit them for their own transmissions [5][6][7]. Thanks to the development of advanced signal processing and interference management techniques, cooperative spectrum sharing is considered as an alternative way to share spectrum more efficiently between primary and secondary users. Instead of transmitting in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered ... |

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On throughput and delay scaling with cooperative spectrum sharing,” in
- Han, Ting, et al.
- 2011
(Show Context)
Citation Context ...ing in idle time or on idle frequency, the SUs relay primary packets, and transmit their own packets with superimposed signal [8][9][10][11], or with a time[12][13][14], frequency-[15][16], or space-[17] division based cooperative relaying scheme. With appropriate cooperation between the two networks, the throughput or the power efficiency of the PUs can be guaranteed or improved, whereas the SUs gain more transmission opportunities. The literature on cooperative spectrum sharing networks addresses the optimal relay selection and resource allocation [12][13][14], and presents scaling laws [18][19][20], assuming that users are always willing to cooperate and always have packets to transmit. Non-backlogged traffic is considered for various cooperative spectrum sharing schemes in [21][22][23][24]. These works characterize the stable-throughput region under stochastic packet arrival and transmission processes, however, still assuming that the SUs always cooperate. In this paper we formulate the dilemma of the secondary user that needs to transmit a stream of randomly arriving packets. As the primary performance needs to be guaranteed, the SU may have significant cost of cooperation, in ter... |

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Dynamic programming and optimal control, 2nd ed.
- Bersekas
- 2001
(Show Context)
Citation Context ... the performance of reinforcement learning for the cases when this knowledge is not available. The MDP framework and its variations such as constrained MDP and Partially Observable MDP (POMDP) [25] have been used extensively for optimizing control strategies in discrete time stochastic systems in general. In the area of spectrum sharing networks with opportunistic secondary access MDP has been used to design sensing and access strategies for the SUs, when the primary traffic can be modeled with some known stochastic processes [2][3][5][6]. Reinforcement learning techniques, such as Q-learning [26] and R-learning [27] provide online optimization tools that can solve MDPs it2 eratively without a priori knowledge of the state transition probabilities, and therefore, has been used for secondary access or interference control design, when the stochastic behavior of the primary system, or of the other interfering secondary systems are not known a priori [4][6][7]. In this paper we consider a primary and a secondary node pair, both with dynamic traffic and unreliable transmission channel. The SU aims at trading off the cost of cooperative relaying and the increased delay of opportunistic tran... |

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Interference in large wireless networks,” Found.
- Georgiadis, Neely, et al.
- 2006
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Citation Context ... are not received successfully are retransmitted. We assume that ACK/NACK messages from the PR and the SR do not get lost. The resulting queuing networks for opportunistic and cooperative spectrum sharing are shown in Fig. 1(a) and (b), respectively. We can see that in both cases the primary and the secondary queues are coupled, more precisely, the service rate of the ST depends on the status of the queue at the PT. III. The Stable-Throughput Region Let us first evaluate the stable-throughput regions of the considered spectrum sharing methods. We follow the notion of strong stability given in [28][29], for slotted systems with time varying service process. To define strong stability, let us denote the queue length at the beginning of a time slot n as Q(n), the number of arrivals in time slot n as A(n), and the service rate as B(n). We assume that arrivals happen at the end of the time slot, and can be served only in the following slot. Then, the queue evolves, as: Q(n + 1) = max[Q(n) − B(n), 0] + A(n). Definition 1. The queue is strongly stable, if [28]: lim sup N→∞ 1 N N∑ n=1 E[Q(n)] < ∞. (1) That is, the queue is strongly stable, if it has a bounded average queue length. A network of... |

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Cooperate or not: the secondary user’s dilemma in hierarchical spectrum sharing network,” in
- Wang, Fodor
- 2013
(Show Context)
Citation Context ...function. A(s) denotes the set of allowed actions in state s. We have: A(s) = { {0} if s ∈ {(Qp,Qs),Qp = 0 and Qs ∈ N0} {0, 1} if s ∈ {(Qp,Qs),Qp 0 and Qs ∈ N0} . • p : S × A → Δ(S): the transition function, where Δ(S) denotes the set of all probability distributions on S. The probability that the process moves to state s′ after taking action a in state s is given by pa(s, s′) = 5 P(st+1 = s′|st = s, at = a), which depends on the arrival rates, and also on the state and action dependent service rates. The derivation of state transition probabilities is straightforward, examples are given in [32]. • c : S × A → R: the cost function c(s, a) denoting the immediate cost that depends on the present state and the selected action. A general cost function for queue-length controlled system is c(s, a) = B(a)+H(s), where B(a) ≥ 0 represents the cost of selecting action a, and H(s) ≥ 0 is a cost that depends on the system state. We consider: c(s, a) = B(a) + H(s) = Cta +ChQs, (6) that is, we set B(a) = Cta to represent the additional power consumption of relaying the primary packet, and H(s) = ChQs, where Ch denotes the cost of the ST for holding one packet in its queue for one time slot and th... |