MIMO Active Interference Alignment for Underlay Cognitive Radio

Wu, Jen-Ming; Yang, Tsan-Fei; Chou, Hsin-Jui

doi:10.1109/iccw.2010.5503877

Cited by 12 publications

(21 citation statements)

References 7 publications

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“…Recently in [22], the problem of cooperative spectrum leasing based on a game theoretical approach in an IA network composed of primary and secondary users has been studied. In [23]- [25], authors study the use of IA in underlay CR systems, while the application of IA in CR femtocell networks has been studied in [26].…”

Section: A Related Workmentioning

confidence: 99%

Spatial Sensing and Cognitive Radio Communication in the Presence of a <inline-formula> <tex-math notation="TeX">$K$</tex-math></inline-formula>-User Interference Primary Network

Alizadeh

Bahrami

Maleki

et al. 2015

IEEE J. Select. Areas Commun.

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Abstract-We study the feasibility of cognitive radio (CR) communication in the presence of a K-user multi-input multioutput (MIMO) interference channel as the primary network. Assuming that the primary interference network has unused spatial degrees of freedom (DoFs), we first investigate the sufficient condition on the number of antennas at the secondary transmitter under which the secondary system can communicate while causing no interference to the primary receivers. We show that, to maximize the benefit, the secondary transmitter should have at least the same number of antennas as the spatial DoFs of the primary system. We then derive the secondary precoding and decoding matrices to have zero interference leakage into the primary network while the signal-to-interference plus noise ratio (SINR) at the secondary receiver is maximized. As the success of the secondary communication depends on the availability of unused DoFs, we then propose a fast sensing method based on the eigenvalue analysis of the received signal covariance matrix to determine the availability of unused DoFs or equivalently spatial holes. Since the proposed fast sensing method cannot identify the indices of inactive primary streams, we also provide a fine sensing method based on the generalized likelihood ratio test (GLRT) to decide the absence of individual primary streams. Simulation results show that the proposed CR sensing and transmission scheme can, in practice, provide a significant throughput while causing no interference to the primary receivers, and that the sensing detects the spatial holes of the primary network with high detection probability.Index Terms-Cognitive radio, K-user MIMO interference channel, interference alignment, null space sensing, spatial holes, eigenvalue-based sensing, GLRT detector.

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Section: A Related Workmentioning

confidence: 99%

Spatial Sensing and Cognitive Radio Communication in the Presence of a <inline-formula> <tex-math notation="TeX">$K$</tex-math></inline-formula>-User Interference Primary Network

Alizadeh

Bahrami

Maleki

et al. 2015

IEEE J. Select. Areas Commun.

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“…In other words, VFDM exploits the frequency selectivity of Rayleigh fading multipath channels to identify transmit opportunities and devise a suitable precoder to null the cross-tier interference when perfect channel state information (CSI) is available at the secondary transmitter. Different from other interference management techniques for multicell networks [3]- [5], VFDM does not require either cooperation/coordination between the two considered cells, or multiple antenna installation at the transmitter/receiver.…”

Section: Introductionmentioning

confidence: 99%

On the Practical Implementation of VFDM-based Opportunistic Systems: Issues and Challenges

Maso

Cardoso

Baştuğ

et al. 2012

REV-JEC

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Abstract-Vandermonde-subspace frequency division multiplexing (VFDM) is a physical layer technique for cognitive twotiered networks, allowing for the coexistence of an orthogonal frequency division multiplexing (OFDM) legacy system and a cognitive secondary system in a time division duplex mode. It consists of a linear null-space precoder used by the secondary transmitter to effectively cancel the interference towards one or more primary receivers, while guaranteeing a non-negligible rate to a served secondary receiver. In this work, we propose an implementation of an experimental test-bed using the new SDR4All platform developed at the Alcatel-Lucent Chair on Flexible Radio (SUPELEC) to take a step towards a proof of concept of a VFDM-based system. We focus on the secondary link, where an opportunistic transmitter/receiver pair communicates over moderately frequency selective channels, characterized by very short root mean square (r.m.s.) delay spreads and non uniform power delay profiles (PDP). The obtained results show the practical feasibility of a VFDM transmission over a secondary link. However, a significant bit error rate (BER) loss with respect to the previously shown achievable theoretical performance is evident. A thorough analysis of the structure of the VFDM precoder is carried out and the impact of the channel characteristics on the performance of the opportunistic system is discussed. Numerical findings demonstrate that the potential BER drop can be addressed by designing a suitable flexible receiver able to deal with the effect induced by non uniform PDP and short r.m.s. delay spread channels.

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“…However, it is hard to verify these conditions in absence of coordination among the macrocell and the small cell tiers [35], [39], [41], [53].…”

Section: B Implicit Coordination Scheme For Mues and Sbssmentioning

confidence: 99%

“…In order to apply an IA based solution and benefit from complete interference suppression, the knowledge of the cross channel information H kn is required at each SBS (e.g., it can be acquired assuming reciprocity of uplink and downlink channels [39] or through CSI information exchange [28] 4 ). Furthermore, by considering that the channel coefficients in H kn are identically and independently distributed, the existence of a solution for the IA problem only depends on the dimensions of the problem (d n , A n , d k , A k , B) as discussed in [43], [44].…”

Section: A Cooperative Spatial Coding Techniques For Small Cell Tranmentioning

confidence: 99%

“…In turn, the SBSs are required to adapt their transmission schemes to the current macrocell spectrum allocation so as to control the interference brought to the nearby MUEs and the other SUEs. Through this assumption, which is common in non-cooperative networks [22], [35], [39], the macrocell tier can optimize its own transmissions while remaining oblivious of the underlaid small cell transmissions, which allows for higher network scalability. Accordingly, the MBS performs a classical waterfilling power allocation over the set of antennas A k as in [36, Section 7.1.1], based the knowledge of the channel realizations H 0n .…”

Section: Introductionmentioning

confidence: 99%

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Improving Macrocell-Small Cell Coexistence Through Adaptive Interference Draining

Pantisano

Bennis²,

Saad³

et al. 2014

IEEE Trans. Wireless Commun.

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Abstract-The deployment of underlay small base stations (SBSs) is expected to significantly boost the spectrum efficiency and the coverage of next-generation cellular networks. However, the coexistence of SBSs underlaid to a macro-cellular network faces important challenges, notably in terms of spectrum sharing and interference management. In this paper, we propose a novel game-theoretic model that enables the SBSs to optimize their transmission rates by making decisions on the resource occupation jointly in the frequency and spatial domains. This procedure, known as interference draining, is performed among cooperative SBSs and allows to drastically reduce the interference experienced by both macro-and small cell users. At the macrocell side, we consider a modified waterfilling policy for the power allocation that allows each macrocell user (MUE) to focus the transmissions on the degrees of freedom over which the MUE experiences the best channel and interference conditions. This approach not only represents an effective way to decrease the received interference at the MUEs but also grants the SBS tier additional transmission opportunities and allows for a more agile interference management. Simulation results show that the proposed approach yields significant gains at both macrocell and small cell tiers, in terms of average achievable rate per user, reaching up to 37%, relative to the non-cooperative case, for a network with 150 MUEs and 200 SBSs.

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MIMO Active Interference Alignment for Underlay Cognitive Radio

Cited by 12 publications

References 7 publications

Spatial Sensing and Cognitive Radio Communication in the Presence of a <inline-formula> <tex-math notation="TeX">$K$</tex-math></inline-formula>-User Interference Primary Network

Spatial Sensing and Cognitive Radio Communication in the Presence of a <inline-formula> <tex-math notation="TeX">$K$</tex-math></inline-formula>-User Interference Primary Network

On the Practical Implementation of VFDM-based Opportunistic Systems: Issues and Challenges

Improving Macrocell-Small Cell Coexistence Through Adaptive Interference Draining

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