On the Cooperative Diversity Gain in Underlay Cognitive Radio Systems

Hong, Jun‐Pyo; Hong, Bi; Ban, Tae Won; Choi, Wan

doi:10.1109/tcomm.2011.101411.100677

Cited by 93 publications

(74 citation statements)

References 20 publications

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“…Through analysis, we know that P p out , P s out , and P o out decrease with the increasing of P p from (16), (22), and (23), and they meet the simulation results in Figure 5. Because P p is the transmission power of the PT, the outage probability of the primary system will be better with the increasing of P p .…”

Section: Simulation Results and Discussionsupporting

confidence: 72%

“…Outage performances with relay selection in Rayleigh fading channels were studied in [20], and the full diversity order has been obtained for Rayleigh fading channels in [21,22]. Moreover, the authors of [23] have analyzed the impact of cooperation communications on the outage probability of cognitive radio networks over the Nakagami-m fading channel and generalized the contributions in [21,22]. While more and more achievements on outage performance with perfect channel state information have been obtained, a lot of attention has been put into the one with imperfect channel state information.…”

Section: Introductionmentioning

confidence: 99%

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Outage performance of relay-assisted primary and secondary transmissions in cognitive relay networks

Zhao

Sun

Chen

et al. 2014

J Wireless Com Network

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In this paper, a two-phase protocol for relay-assisted spectrum sharing in cognitive relay network is proposed. The primary system comprises a transmitter-receiver pair (PT-PR) and a decode-and-forward relay (Relay), while the secondary system comprises a transmitter-receiver pair (ST-SR). In the proposed protocol, the Relay assists the transmissions of the primary users as well as the secondary users where there is no direct link between the ST and the SR. Outage probabilities of the primary system and the secondary system are derived and verified through simulations. Compared with the protocol without cooperation, better outage performance of the primary system is achieved. Meanwhile, though the ST causes interference to the PR, the interference is compensated by the cooperation of the Relay. Moreover, the proposed protocol realizes the communications of the secondary users on the condition that the secondary transmission link is not ideal.

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Section: Simulation Results and Discussionsupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Outage performance of relay-assisted primary and secondary transmissions in cognitive relay networks

Zhao

Sun

Chen

et al. 2014

J Wireless Com Network

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“…It is assumed that SU has the instantaneous CSI of the secondary transmission links and the links from PT to SU, which can be obtained by a pilot-aided channel estimation or CSI feedback [14,23]. Moreover, the two SUs are assumed to know the average CSI between themselves and PD and also the average CSI between PT and PD.…”

Section: System and Channel Modelmentioning

confidence: 99%

Optimal resource allocation for cognitive radio networks with primary user outage constraint

Lan

Chen

Zhang

et al. 2015

J Wireless Com Network

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In this paper, we investigate the problem of power allocation in cognitive underlay networks, where a secondary user (SU) is allowed to coexist with a primary user (PU). We consider three transmission models for the secondary link: (i) one-way transmission with relay assisted, (ii) two-way transmission with a direct link, and (iii) two-way transmission with relay assisted. In conventional interference-limited cognitive networks, the instantaneous channel state information (CSI) of a PU is required to suppress SU's transmit power to guarantee the quality of service (QoS) of the PU, which increases the feedback burden in practice. To tackle this issue, in this article we take primary outage probability as a new criterion to measure the QoS of the PU, where only the statistical CSI of the PU is required. Firstly, we derive the primary outage constraints for the three models, respectively. Then, with the newly obtained constraints, we formulate optimization problems to maximize the channel rate of the SU. Finally, we derive the optimal solutions for power allocation with respect to different parameters, respectively. Simulation results verify the performance improvement of the proposed schemes.

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“…Moreover, the transmit power of a SU is physically limited by its own maximum output power, which is essentially equivalent to the peak interference power constraint. Nevertheless, it was previously demonstrated that peak interference-power constraint will not affect system performance when it is large enough [11], [12]. Therefore, we consider only the average interference power constraint in the optimization problem above.…”

Section: A Criteria For Optimal Power Allocationmentioning

confidence: 99%

Cooperative AF Relaying in Spectrum-Sharing Systems: Outage Probability Analysis under Co-Channel Interferences and Relay Selection

Xia

Aı̈ssa

2012

IEEE Trans. Commun.

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Abstract-For cooperative amplify-and-forward (AF) relaying in spectrum-sharing wireless systems, secondary users share spectrum resources originally licensed to primary users to communicate with each other and, thus, the transmit power of secondary transmitters is strictly limited by the tolerable interference powers at primary receivers. Furthermore, the received signals at a relay and at a secondary receiver are inevitably interfered by the signals from primary transmitters. These co-channel interferences (CCIs) from concurrent primary transmission can significantly degrade the performance of secondary transmission. This paper studies the effect of CCIs on outage probability of the secondary link in a spectrum-sharing environment. In particular, in order to compensate the performance loss due to CCIs, the transmit powers of a secondary transmitter and its relaying node are respectively optimized with respect to both the tolerable interference powers at the primary receivers and the CCIs from the primary transmitters. Moreover, when multiple relays are available, the technique of opportunistic relay selection is exploited to further improve system performance with low implementation complexity. By analyzing lower and upper bounds on the outage probability of the secondary system, this study reveals that it is the tolerable interference powers at primary receivers that dominate the system performance, rather than the CCIs from primary transmitters. System designers will benefit from this result in planning and designing next-generation broadband spectrum-sharing systems.Index Terms-Amplify-and-forward (AF) relaying, co-channel interference (CCI), interference power constraints, outage probability, relay selection, spectrum sharing.

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On the Cooperative Diversity Gain in Underlay Cognitive Radio Systems

Cited by 93 publications

References 20 publications

Outage performance of relay-assisted primary and secondary transmissions in cognitive relay networks

Outage performance of relay-assisted primary and secondary transmissions in cognitive relay networks

Optimal resource allocation for cognitive radio networks with primary user outage constraint

Cooperative AF Relaying in Spectrum-Sharing Systems: Outage Probability Analysis under Co-Channel Interferences and Relay Selection

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