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## Dynamic resource allocation in cognitive radio networks (2010)

Venue: | IEEE Signal Process. Mag |

Citations: | 51 - 5 self |

### Citations

12389 |
Elements of Information Theory
- Cover, Thomas
- 1991
(Show Context)
Citation Context ...log ∣∣∣I+HT−1/2ŜT−1/2HH∣∣∣ − Tr(Ŝ). (11) The above problem can be shown equivalent to the standard point-to-point MIMO channel capacity optimization problem subject to a single sum-power constraint =-=[17]-=-, and its solution can be expressed as Ŝ? = VΣVH , where V is obtained from the singular-value decomposition (SVD) given as follows: HT−1/2 = UΘVH , with Θ = Diag([θ1, . . . , θT ]) and T = min(M,N),... |

7427 | Convex optimization
- Boyd, Vandenberghe
- 2004
(Show Context)
Citation Context ...ated SOCP problem is feasible, we know that the optimal solution of (P4) for α, denoted by α?, must satisfy α? ≥ α; otherwise, α? < α. Based on this fact, α? can be found by a simple bisection search =-=[14]-=-; with α?, the corresponding optimal solution for vk’s in (P4) can also be obtained. The above technique has also been applied in [27] for (P4) without the PIPCs. The SINR balancing problem for the co... |

3235 | The capacity of wireless networks
- Gupta, Kumar
- 2000
(Show Context)
Citation Context ...rk and jointly optimize their transmissions to maximize the SU network throughput with a prescribed PU network throughput guarantee. From this viewpoint, recent advances in network information theory =-=[8]-=- have provided promising guidelines to approach the fundamental limits of such networks. However, from a practical viewpoint, the centralized design approach for PU and SU networks is not desirable, s... |

1063 |
CVX: Matlab software for disciplined convex programming [Online]. Available: http://stanford.edu/~boyd/cvx
- Grant, Boyd
(Show Context)
Citation Context ...nt Im(hv) = 0. Thereby, (P1-S) can be converted into a second-order cone programming (SOCP) [14] problem, which is convex and thus can be efficiently solved by available convex optimization softwares =-=[15]-=-. Alternatively, (P1-S) can be shown equivalent to its Lagrange dual problem [13], which is a convex semi-definite programming (SDP) [14] problem and is thus efficiently solvable [15]. For (P1-S) in t... |

713 |
Cognitive radio: making software radios more personal
- Mitola, J, et al.
- 1999
(Show Context)
Citation Context ...lated, as will be reviewed in this article. To date, quite a few operation models have been proposed for CRs; however, there is no consensus yet on the terminology used for the associated definitions =-=[1]-=-, [2], [3]. Generally speaking, there are two basic operation models for CRs: Opportunistic Spectrum Access (OSA) vs. Spectrum Sharing (SS). In the OSA model, the SUs are allowed to transmit over the ... |

478 |
A new achievable rate region for the interference channel
- Han, Kobayashi
- 1981
(Show Context)
Citation Context ...gion for the Gaussian IC under PTPCs, which consists of all the simultaneously achievable rates of all the users, still remains unknown in general even for the case of K = 2 and Ak = Bk = 1, k = 1, 2 =-=[29]-=-. A pragmatic approach that leads to suboptimal achievable rates in the Gaussian IC is to restrict the system to operate in a decentralized manner, i.e., allowing only single-user encoding and decodin... |

462 |
Information capacity and power control in single-cell multiuser communications,” presented at the Int
- Knopp, Humblet
- 1995
(Show Context)
Citation Context ...ons for the optimality of TDMA/FDMA, i.e., when they are optimal to achieve the system sum-capacity. For the traditional single-antenna fading MAC under the user ATPCs over time, it has been shown in =-=[47]-=- that TDMA is optimal for achieving the ergodic/long-term sum-capacity. This result has been shown to hold for the fading CR MAC and CR BC under both the ATPCs and AIPCs in [48], where by exploiting t... |

448 | A survey of dynamic spectrum access
- Zhao, Sadler
- 2007
(Show Context)
Citation Context ..., as will be reviewed in this article. To date, quite a few operation models have been proposed for CRs; however, there is no consensus yet on the terminology used for the associated definitions [1], =-=[2]-=-, [3]. Generally speaking, there are two basic operation models for CRs: Opportunistic Spectrum Access (OSA) vs. Spectrum Sharing (SS). In the OSA model, the SUs are allowed to transmit over the band ... |

371 | Zero-forcing methods for downlink spatial multiplexing in multiuser MIMO channels
- Spencer, Swindlehurst, et al.
- 2004
(Show Context)
Citation Context ...h the optimal solution of S is known to be derivable from the SVD of H [17]. For the second case, assuming that Γj = 0, ∀j, the solution for (P1) is then obtained by the “zero-forcing (ZF)” algorithm =-=[18]-=-, which first projects H into the space orthogonal to all Gj’s, and then designs the optimal S based on the SVD of the projected channel. Note that the (nontrivial) ZF-based solution exists only when ... |

339 | achievable rates, and sum-rate capacity of Gaussian MIMO broadcast channels
- Vishwanath, Jindal, et al.
- 2003
(Show Context)
Citation Context ...e point-to-point CR channel, the standard Lagrange duality method cannot be applied for this problem. For (P3) in the case without the PIPCs, a so-called “BC-MAC duality” relationship was proposed in =-=[23]-=- to transform the non-convex MIMO-BC problem into an equivalent convex MIMO-MAC problem, which is solvable by efficient convex optimization techniques such as the interior point method. In [24], anoth... |

300 | Spectrum sharing for unlicensed bands
- Etkin, Parekh, et al.
- 2007
(Show Context)
Citation Context ...constraints have been characterized. For the traditional singleantenna IC with interference treated as noise, the optimality of TDMA/FDMA for the sum capacity has been investigated under the ATPCs in =-=[49]-=-, [50]. It would be interesting to extend these results to the case of CR IC under the additional PIPCs and/or AIPCs. B. Peak vs. Average Interference Power Constraints: A New Interference Diversity F... |

291 | Sensing-throughput tradeoff for cognitive radio networks
- Liang, Zeng, et al.
- 2006
(Show Context)
Citation Context ...sults indicate that all the PU transmitters are inactive at this band with a high probability. Spectrum sensing is now a very active area for research; the interested readers may refer to, e.g., [4], =-=[5]-=-, [6], [7] for an overview of the state-of-art results in this area. As a counterpart, the SS model allows the SUs to transmit simultaneously with PUs at the same band even if they are active, provide... |

270 | Achievable rates in cognitive radio channels
- Devroye, Mitran, et al.
- 2006
(Show Context)
Citation Context ...(cognition) of the PU network. Following this (simplified) decentralized approach, there are furthermore two design paradigms proposed for SS-based CRs. 2One is based on the “cognitive relay” concept =-=[9]-=-, where the SU transmitter allocates only part of its power to deliver the SU messages, and uses the remaining power to relay the PU messages so as to compensate for the additional SU interference exp... |

269 | Distributed multiuser power control for digital subscriber lines
- Yu, Ginis, et al.
- 2002
(Show Context)
Citation Context ...terative user optimizations has been pursued in the singleantenna but multi-carrier based interference channels such as the wired discrete-multi-tone (DMT) based digital subscriber line (DSL) network =-=[33]-=-, and the wireless OFDM based ad hoc network [34]. One important question to answer for such iterative algorithms is under what conditions the algorithm will guarantee to converge to a local optimal p... |

264 | Breaking spectrum gridlock with cognitive radios: an information theoretic perspective
- Jafar, Srinivasa, et al.
- 2009
(Show Context)
Citation Context ...will be reviewed in this article. To date, quite a few operation models have been proposed for CRs; however, there is no consensus yet on the terminology used for the associated definitions [1], [2], =-=[3]-=-. Generally speaking, there are two basic operation models for CRs: Opportunistic Spectrum Access (OSA) vs. Spectrum Sharing (SS). In the OSA model, the SUs are allowed to transmit over the band of in... |

218 |
Solution of the multiuser downlink beamforming problem with individual SINR constraints
- Schubert, Boche
- 2004
(Show Context)
Citation Context ...) can also be obtained. The above technique has also been applied in [27] for (P4) without the PIPCs. The SINR balancing problem for the conventional MISOBC without the PIPCs has also been studied in =-=[28]-=-, where an algorithm was proposed using the virtual uplink formulation and a fixed-point iteration. However, this algorithm cannot be extended directly to deal with multiple PIPCs for the case of CR M... |

208 |
Interference alignment, and the degrees of freedom of the K user interference channel
- Cadambe, Jafar
- 2009
(Show Context)
Citation Context ...l solution for this problem. For the same problem setup, there have been recent progresses on characterizing the maximum achievable “degrees of freedom (DoF)” for the user sum-rate (i.e., µk = 1, ∀k) =-=[30]-=-. Next, we discuss some feasible solutions for (P5). First, it is worth noting that for (P5) in the case without the PIPCs, a commonly adopted suboptimal approach is to iteratively optimize each user’... |

200 | Dual methods for nonconvex spectrum optimization of multicarrier systems,”
- Yu, Lui
- 2006
(Show Context)
Citation Context ... also non-convex. For this case, even when the optimal solutions of the L subproblems are obtainable, the optimal value of (P6-D) in general only serves as an upper bound on that of (P6). However, in =-=[45]-=- it is pointed out that if a set of so-called “time-sharing” conditions are satisfied by a non-convex optimization problem, the duality gap for this problem and its dual problem is indeed zero. Furthe... |

185 | A tutorial on decomposition methods for network utility maximization,”
- Palomar, Chiang
- 2006
(Show Context)
Citation Context ...], · · · ,SK [l]) with Ul(·)’s denoting individual utility functions. Since both the ATPC and AIPC involve L transmit covariance matrices, the Lagrange dual decomposition (see, e.g., a tutorial paper =-=[44]-=-) is a general method to deal with this type of average constraints for optimization over a number of parallel dimensions, which is explained as follows. By introducing a set of dual variables, νk’s, ... |

177 | Distributed Interference Compensation for Wireless Networks”,
- Huang, Berry, et al.
- 2006
(Show Context)
Citation Context ...he singleantenna but multi-carrier based interference channels such as the wired discrete-multi-tone (DMT) based digital subscriber line (DSL) network [33], and the wireless OFDM based ad hoc network =-=[34]-=-. One important question to answer for such iterative algorithms is under what conditions the algorithm will guarantee to converge to a local optimal point. This problem has been addressed in the cont... |

153 | Linear precoding via conic optimization for fixed MIMO receivers
- Wiesel, Eldar, et al.
- 2006
(Show Context)
Citation Context ... Based on this fact, α? can be found by a simple bisection search [14]; with α?, the corresponding optimal solution for vk’s in (P4) can also be obtained. The above technique has also been applied in =-=[27]-=- for (P4) without the PIPCs. The SINR balancing problem for the conventional MISOBC without the PIPCs has also been studied in [28], where an algorithm was proposed using the virtual uplink formulatio... |

144 |
Shitz), “Fading channels: Information-theoretic and communications aspects
- Biglieri, Proakis, et al.
- 1998
(Show Context)
Citation Context ...e power from the K SUs, which is averaged over the L transmit dimensions. Note that DRA for traditional (non-CR) wireless networks under PTPC and/or ATPC has been thoroughly studied in the literature =-=[12]-=-, while the study of DRA subject to PIPC and/or AIPC as well as their various combinations with PTPC/ATPC is unique to CR networks and is relatively new. In order to gain more insights into the optima... |

143 |
Multi-access fading channels-Part I: polymatroid structure, optimal resource allocation and throughput capacities
- Tse, Hanly
- 1998
(Show Context)
Citation Context ...the given user rate weights satisfy that µ1 ≥ µ2 ≥ · · · ≥ µK ≥ 0; thus, the optimal decoding order of users at the S-BS to maximize the weighted sum-rate is in accordance with the reverse user index =-=[19]-=-. Accordingly, the WSRMax for the CR MIMO-MAC can be expressed as Max. S1,··· ,SK K∑ k=1 µk log ∣∣∣I+∑ki=1HiSiHHi ∣∣∣∣∣∣I+∑k−1i=1 HiSiHHi ∣∣∣ (P2) s. t. Tr(Sk) ≤ Pk, k = 1, . . . ,K K∑ k=1 Tr ( GkjSkG... |

135 | Exploiting multi-antennas for opportunistic spectrum sharing in cognitive radio networks
- Zhang, Liang
- 2008
(Show Context)
Citation Context ...he following discussions. Specifically, the optimal transmit covariance to achieve the CR point-to-point MIMO channel capacity under both the PTPC and PIPCs can be obtained from the following problem =-=[13]-=-: Max. S log ∣∣I+HSHH ∣∣ (P1) s. t. Tr(S) ≤ P Tr ( GjSG H j ) ≤ Γj , j = 1, · · · , J S 0 where for conciseness we have removed the SU index k in the symbol notations since K = 1, while S 0 means ... |

135 | Transmitter optimization for the multi-antenna downlink with per-antenna power constraints,”
- Yu, Lan
- 2007
(Show Context)
Citation Context ...sed in [23] to transform the non-convex MIMO-BC problem into an equivalent convex MIMO-MAC problem, which is solvable by efficient convex optimization techniques such as the interior point method. In =-=[24]-=-, another form of BC-MAC duality, the so-called “mini-max duality” was explored to solve the MIMO-BC problem under a special case of GLTCC: the per-antenna transmit power constraint. However, these ex... |

130 | Power Control by Geometric Programming,”
- Chiang, Tan, et al.
- 2007
(Show Context)
Citation Context ...ion vectors, this algorithm iteratively updates the SU transmit precoding vectors (based on the “network duality” [39]) or the power allocation vectors (by solving geometric programming (GP) problems =-=[40]-=-), with the others being fixed. It is worth pointing out that there are other problem formulations different from (P5) to address the transmit optimization for the CR MIMO-IC. In [41], a new criterion... |

129 | Dynamic Spectrum Management: Complexity and Duality,”
- Luo, Zhang
- 2008
(Show Context)
Citation Context ...of DRA problems in the form of (P6), the associated time-sharing conditions are usually satisfied asymptotically as L → ∞ under some cautious considerations on the continuity of channel distributions =-=[46]-=-. Therefore, the dual decomposition method could still be applied to solve (P6) in the non-convex case for sufficiently large values of L, provided that the optimal solutions for the subproblems in (1... |

120 | Optimal linear cooperation for spectrum sensing in cognitive radio networks
- Quan, Cui, et al.
- 2008
(Show Context)
Citation Context ...ng results indicate that all the PU transmitters are inactive at this band with a high probability. Spectrum sensing is now a very active area for research; the interested readers may refer to, e.g., =-=[4]-=-, [5], [6], [7] for an overview of the state-of-art results in this area. As a counterpart, the SS model allows the SUs to transmit simultaneously with PUs at the same band even if they are active, pr... |

106 | Optimized signaling for MIMO interference systems with feedback,”
- Ye, Blum
- 2003
(Show Context)
Citation Context ...tively optimize each user’s transmit covariance subject to its individual PTPC with the transmit covariances of all the other users fixed. This decentralized approach has been first proposed in [31], =-=[32]-=- to obtain some local optimal points for (P5) with the PTPCs only, where they differ in that the one in [31] maximizes the user individual rate at each iteration, while the one in [32] maximizes the u... |

96 |
On capacity under receive and spatial spectrum-sharing constraints
- Gastpar
- 2007
(Show Context)
Citation Context ... a more feasible SS design for the SU to protect the PU is to impose a constraint on the maximum SU interference power at the PU receiver, also known as the “interference temperature (IT)” constraint =-=[10]-=-, by assuming that the SU-to-PU channels are either perfectly known at the SU transmitters, or can be practically estimated. In this article, we will focus our study on the IT-based SS model for CRs, ... |

92 | The ellipsoid method: a survey
- Bland, Goldfarb, et al.
- 1981
(Show Context)
Citation Context ...loped to solve (P1-D) by alternating between solving d(η) for a given η and updating η to minimize d(η). At each iteration, η can be updated by a subgradient-based method such as the ellipsoid method =-=[16]-=-, according to the subgradients of d(η), which can be shown equal to P −Tr(S?) and Γj−Tr ( GjS ?GHj ) for η0 and ηj , j 6= 0, respectively, where S? denotes the optimal S to obtain d(η) for a given η.... |

76 | Analysis of iterative waterfilling algorithm for multiuser power control in digital subscriber lines,”
- Luo, Pang
- 2006
(Show Context)
Citation Context ...itions the algorithm will guarantee to converge to a local optimal point. This problem has been addressed in the contexts of both multi-carrier and multi-antenna based interference channels in, e.g., =-=[35]-=-, [36], via game-theoretic approaches. However, the above iterative approach cannot be applied directly to solve (P5) with both the PIPCs and PTPCs, since each PIPC involves all the user transmit cova... |

73 |
Optimal and suboptimal transmit beamforming,”
- Bengtsson, Ottersten
- 2001
(Show Context)
Citation Context ...S intended for the kth SU; and hk represents Hk for the MISO-BC case. Similarly as for (P1-S), by treating hHk vk on the left-hand side (LHS) of each SINR constraint in (P4) as a positive real number =-=[26]-=-, it can be shown that (P4) for a given α is equivalent to a SOCP feasibility problem and thus efficiently solvable [15]. For a given α, if the associated SOCP problem is feasible, we know that the op... |

68 |
Signal processing in cognitive radio
- Ma, Li, et al.
- 2009
(Show Context)
Citation Context ... indicate that all the PU transmitters are inactive at this band with a high probability. Spectrum sensing is now a very active area for research; the interested readers may refer to, e.g., [4], [5], =-=[6]-=-, [7] for an overview of the state-of-art results in this area. As a counterpart, the SS model allows the SUs to transmit simultaneously with PUs at the same band even if they are active, provided tha... |

66 |
Shitz), “The capacity region of the Gaussian multiple-input multiple-output broadcast channel
- Weingarten, Steinberg, et al.
- 2006
(Show Context)
Citation Context ...der two commonly adopted design criteria for the traditional multi-antenna Gaussian BC in the literature: One is for the MIMO-BC deploying the non-linear “dirty-paper-coding (DPC)” at the transmitter =-=[22]-=-, which maximizes the weighted sum-rate of all the users (i.e., the WSRMax problem); the other is for the MISO-BC (single-antenna for each SU receiver) deploying only linear encoding at the transmitte... |

62 | Competitive design of multiuser MIMO systems based on game theory: A unified view,”
- Scutari, Palomar, et al.
- 2008
(Show Context)
Citation Context ... the algorithm will guarantee to converge to a local optimal point. This problem has been addressed in the contexts of both multi-carrier and multi-antenna based interference channels in, e.g., [35], =-=[36]-=-, via game-theoretic approaches. However, the above iterative approach cannot be applied directly to solve (P5) with both the PIPCs and PTPCs, since each PIPC involves all the user transmit covariance... |

60 | A review on spectrum sensing for cognitive radio: Challenges and solutions,”
- Zeng, Liang, et al.
- 2010
(Show Context)
Citation Context ...cate that all the PU transmitters are inactive at this band with a high probability. Spectrum sensing is now a very active area for research; the interested readers may refer to, e.g., [4], [5], [6], =-=[7]-=- for an overview of the state-of-art results in this area. As a counterpart, the SS model allows the SUs to transmit simultaneously with PUs at the same band even if they are active, provided that the... |

56 | An introduction to convex optimization for communications and signal processing,”
- Luo, Yu
- 2006
(Show Context)
Citation Context ...s. In particular, this article will focus on DRA problem formulations unique to CR systems under the IT-SS model, and the associated solutions that are non-obvious in comparison with existing results =-=[11]-=- known for the traditional (non-CR) wireless networks. More importantly, we will emphasize the key role of various convex optimization techniques in solving these problems. The remainder of this artic... |

48 | On peak versus average interference power constraints for protecting primary users in cognitive radio networks
- Zhang
- 2009
(Show Context)
Citation Context ...le the latter results in variations of interference power levels over different dimensions although their average level is kept below the same threshold as that for the PIPC. Somehow surprisingly, in =-=[51]-=- it is shown that for the single-antenna PU fading channel subject to the interference from a SU transmitter, the AIPC is in fact better than its PIPC counterpart under the same average power threshol... |

42 | On ergodic sum capacity of fading cognitive multiple-access and broadcast channels
- Zhang, Cui, et al.
- 2009
(Show Context)
Citation Context ..., it has been shown in [47] that TDMA is optimal for achieving the ergodic/long-term sum-capacity. This result has been shown to hold for the fading CR MAC and CR BC under both the ATPCs and AIPCs in =-=[48]-=-, where by exploiting the KKT optimality conditions of the associated optimization problems, the optimality conditions for TDMA in other cases of combined peak/average transmit/interference power cons... |

40 | Spectrum sharing in wireless networks via QoS-aware secondary multicast beamforming,
- Phan, Vorobyov, et al.
- 2009
(Show Context)
Citation Context ...e similarly defined as for the MAC case in (4) and (6), respectively. We focus on the unicast downlink transmission for the CR BC, while for the case of multicast, the interested readers may refer to =-=[21]-=-. For the purpose of exposition, we consider two commonly adopted design criteria for the traditional multi-antenna Gaussian BC in the literature: One is for the MIMO-BC deploying the non-linear “dirt... |

40 |
Power-controlled capacity for interfering MIMO links,” in
- Demirkol, Ingram
- 2001
(Show Context)
Citation Context ... iteratively optimize each user’s transmit covariance subject to its individual PTPC with the transmit covariances of all the other users fixed. This decentralized approach has been first proposed in =-=[31]-=-, [32] to obtain some local optimal points for (P5) with the PTPCs only, where they differ in that the one in [31] maximizes the user individual rate at each iteration, while the one in [32] maximizes... |

39 | Optimal resource allocation for MIMO ad hoc cognitive radio networks,” in
- Kim, Giannakis
- 2008
(Show Context)
Citation Context ...lized optimization is feasible with the global knowledge of all the channels in the SU network, as well as those from different SU-TXs to all PUs, another heuristic algorithm for (P5) was proposed in =-=[38]-=-. By rewriting the SU transmit covariance matrices into their equivalent precoding vectors and power allocation vectors, this algorithm iteratively updates the SU transmit precoding vectors (based on ... |

39 |
Robust cognitive beamforming with partial channel state information,”
- Zhang, Liang, et al.
- 2009
(Show Context)
Citation Context ...ich should be taken into account for the design of practical CR systems. This motivates a new and challenging research direction on robust designs for cognitive beamforming to cope with imperfect CSI =-=[55]-=-, [56]. More investigations on the robust cognitive beamforming designs for more general CR networks and CSI uncertainty models are appealing. Active Interference-Temperature Control: In this article,... |

31 |
Joint beamforming and power control for multiple access channels in cognitive radio networks
- Zhang, Liang, et al.
- 2008
(Show Context)
Citation Context ...of linear instead of non-linear decoder at the receiver will change the user achievable rates for the CR MIMOMAC, thus resulting in new problem formulations for transmit optimization. For example, in =-=[20]-=-, the authors have considered the CR SIMO-MAC (single-antenna for each SU transmitter) with a linear decoder at the receiver, where the power allocation across the SUs is optimized to maximize their s... |

31 |
Robust cognitive beamforming with bounded channel uncertainties,”
- Zheng, Wong, et al.
- 2009
(Show Context)
Citation Context ...ould be taken into account for the design of practical CR systems. This motivates a new and challenging research direction on robust designs for cognitive beamforming to cope with imperfect CSI [55], =-=[56]-=-. More investigations on the robust cognitive beamforming designs for more general CR networks and CSI uncertainty models are appealing. Active Interference-Temperature Control: In this article, we ha... |

30 | Cognitive beamforming made practical: effective interference channel and learning-throughput tradeoff
- Zhang, Gao, et al.
- 2010
(Show Context)
Citation Context ...or the PUs to feed back the required CSI to the CRs. As a result, the SU usually needs to rely on its own observations over the received signals from the primary terminals to extract the required CSI =-=[54]-=-. Nevertheless, the estimated CSI on the SU-to-PU channels may contain errors, which should be taken into account for the design of practical CR systems. This motivates a new and challenging research ... |

28 | On the Gaussian MIMO BC-MAC duality with multiple transmit covariance constraints
- Zhang, Zhang, et al.
- 2012
(Show Context)
Citation Context ...nsmit power constraint. However, these existing forms of BC-MAC duality are yet unable to handle the case with arbitrary numbers of GLTCCs, which is the case for (P3) with both the PTPC and PIPCs. In =-=[25]-=-, a general method was proposed to solve various MIMO-BC optimization problems under multiple GLTCCs, thus including the CR MIMO-BC WSRMax problem given in (P3). For this method, the first step is to ... |

28 | Spectrum management for interferencelimited multiuser communication systems,”
- Hayashi, Luo
- 2009
(Show Context)
Citation Context ...aints have been characterized. For the traditional singleantenna IC with interference treated as noise, the optimality of TDMA/FDMA for the sum capacity has been investigated under the ATPCs in [49], =-=[50]-=-. It would be interesting to extend these results to the case of CR IC under the additional PIPCs and/or AIPCs. B. Peak vs. Average Interference Power Constraints: A New Interference Diversity From a ... |

23 | Optimal power control over fading cognitive radio channel by exploiting primary user CSI
- Zhang
(Show Context)
Citation Context ...e IT constraints for protecting the PU transmissions. Given that the IT constraints in general conservatively lead to an upper bound on the PU capacity loss due to the interference from the SUs [13], =-=[52]-=-, it would be possible to improve the spectrum sharing capacities for both the SUs and PUs over the IT-based methods if additional cognition on the PU transmissions is available at the CR transmitters... |

22 |
Network duality for multiuser MIMO beamforming networks and applications
- Song, Cruz, et al.
- 2007
(Show Context)
Citation Context ...transmit covariance matrices into their equivalent precoding vectors and power allocation vectors, this algorithm iteratively updates the SU transmit precoding vectors (based on the “network duality” =-=[39]-=-) or the power allocation vectors (by solving geometric programming (GP) problems [40]), with the others being fixed. It is worth pointing out that there are other problem formulations different from ... |

19 |
Cognitive MIMO radio
- Scutari, Palomar, et al.
- 2008
(Show Context)
Citation Context ... that a suboptimal method for this problem in the same spirit of the partial channel projection method to reduce the design complexity for each SU transmit covariance matrix has also been proposed in =-=[37]-=-. Moreover, it is noted that Γ(k)j ’s, j = 1, · · · , J , k = 1, · · · ,K , can be searched over the SUs to further improve their weighted sum-rate. Alternatively, assuming that a centralized optimiza... |

18 | On the relationship between the multi-antenna secrecy communications and cognitive radio communications
- Zhang, Zhang, et al.
- 2010
(Show Context)
Citation Context ...R network to achieve the best spectrum sharing throughput. These results lead to a new and universal design paradigm for interference management in CR or other related multiuser communication systems =-=[57]-=-, [58], via appropriately setting the IT levels across the coexisting links. The active IT control approach to interference management for multiuser communication systems is relatively new, and more r... |

8 | Beamforming and rate allocation in MISO cognitive radio networks
- Tajer, Prasad, et al.
- 2010
(Show Context)
Citation Context ...ir instantaneous transmit rates. Thus, the corresponding transmit optimization for the CR MIMO-IC leads to new and more challenging problem formulations than (P5); the interested readers may refer to =-=[42]-=-, [43]. IV. JOINT SPACE-TIME-FREQUENCY DRA OPTIMIZATION In the previous section, we have studied DRA for different CR networks at a single transmit dimension in time/frequency, by focusing on spatial-... |

6 | Interference reduction by beamforming in cognitive networks
- Yiu, Vu, et al.
(Show Context)
Citation Context ...ng (GP) problems [40]), with the others being fixed. It is worth pointing out that there are other problem formulations different from (P5) to address the transmit optimization for the CR MIMO-IC. In =-=[41]-=-, a new criterion was proposed to design the SU link transmission in a CR MISO-IC via an alternative decentralized approach, where each SU-TX independently designs its transmit precoding vector to max... |

5 |
Optimal power allocation for cognitive radio under primary user outage capacity constraint
- Kang, Zhang, et al.
- 2009
(Show Context)
Citation Context ... performances. These PU “null” dimensions could come up in time, frequency, or space. Thus, the IT constraints could be replaced by the more relevant primary link performance margin constraints [52], =-=[53]-=- for the design of DRA in CR networks, in order to optimally exploit the available primary link performance margins to accommodate the interference from the SUs. Following this new paradigm, many new ... |

5 |
Cooperative interference management in multicell downlink beamforming
- Zhang, Cui
- 2010
(Show Context)
Citation Context ...ork to achieve the best spectrum sharing throughput. These results lead to a new and universal design paradigm for interference management in CR or other related multiuser communication systems [57], =-=[58]-=-, via appropriately setting the IT levels across the coexisting links. The active IT control approach to interference management for multiuser communication systems is relatively new, and more researc... |

4 | Iterative spectrum shaping with opportunistic multiuser detection
- Zhang, Cioffi
- 2009
(Show Context)
Citation Context ...tantaneous transmit rates. Thus, the corresponding transmit optimization for the CR MIMO-IC leads to new and more challenging problem formulations than (P5); the interested readers may refer to [42], =-=[43]-=-. IV. JOINT SPACE-TIME-FREQUENCY DRA OPTIMIZATION In the previous section, we have studied DRA for different CR networks at a single transmit dimension in time/frequency, by focusing on spatial-domain... |