Low Complexity Active Interference Cancellation for OFDM Cognitive Radios

Huang, Shih-Gu; Hwang, Chien-Hwa

doi:10.1109/wcnc.2008.230

Cited by 13 publications

(6 citation statements)

References 2 publications

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“…In the subcarrier adjustment stage, for each subcarrier k, the user with largest (24) will occupy the subcarrier instead of user i if the performance is better than it before adjustment. Because of the individual power constraints in uplink, the subcarrier adjustment procedure needs to be done for several iteration times to approach the optimal performance.…”

Section: Theoremmentioning

confidence: 99%

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An uplink resource allocation scheme for OFDMA‐based cognitive radio networks

Wang

et al. 2008

Int J Communication

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SUMMARYCognitive radio makes it possible for an unlicensed user to access a spectrum unoccupied by licensed users. In cognitive radio networks, extra constraints on interference temperature need to be introduced into radio resource allocation. In this paper, the uplink radio resource allocation is investigated for OFDMAbased cognitive radio networks. In consideration of the characteristics of cognitive radio and OFDMA, an improved water-filling power allocation scheme is proposed under the interference temperature constraints for optimal performance. Based on the improved water-filling power allocation, a simple subcarrier allocation algorithm for uplink is proposed. The subcarrier allocation rules are obtained by theoretical deduction. In the uplink subcarrier allocation algorithm, the subcarriers are allocated to the users with the best channel quality initially and then adjusted to improve the system performance. A cursory water-filling level estimation method is used to decrease the complexity of the algorithm. Asymptotic performance analysis gives a lower bound of the stability of the water-filling level estimation. The complexity and performance of the proposed radio resource allocation scheme are investigated by theoretical analysis and numerical results.

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Section: Theoremmentioning

confidence: 99%

“…There have been some publications on this area. Huang and Hwang and Shi et al [24,25] focus on the research topics at PHY layer, while Hwang and Chen [26] investigate the sensing techniques. For resource allocation, [27] considers downlink resource allocation based on OFDM channel identification.…”

Section: Introductionmentioning

confidence: 99%

An uplink resource allocation scheme for OFDMA‐based cognitive radio networks

Wang

et al. 2008

Int J Communication

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“…Since the MMSE solution involves an inverse calculation, the complexity of the solution can be prohibitive as we increase AIC n and LU n . A low complexity solution which depends only on AIC n has been proposed in [4]. …”

Section: Active Interference Cancellationmentioning

confidence: 99%

A low complexity active interference cancellation method for OFDM based cognitive radios

Rammoorthy

Pandian²,

Subramanian³

2010

2010 National Conference on Communications (NCC)

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“…The detection probability of victim signal according to a specific detection power level. 시키더라도 얻을 수 있는 notch depth는 약 15 dB 정 도에 불과하다 [3], [4] . Tone-nulling을 시키고자 하는 대 역에 원하는 정도의 notch depth를 구현하기 위한 방 안으로 AIC가 연구되고 있으며, 이러한 AIC의 가장 큰 특징은 피하고자 하는 대역의 양 옆에 인접한 subcarrier들에 의한 side lobe 특성들을 제거하기 위 한 2개의 subcarrier를 추가하는 것이다.…”

Section: -3 피 간섭 신호 검출 알고리즘 설계unclassified

“…Tone-nulling을 시키고자 하는 대 역에 원하는 정도의 notch depth를 구현하기 위한 방 안으로 AIC가 연구되고 있으며, 이러한 AIC의 가장 큰 특징은 피하고자 하는 대역의 양 옆에 인접한 subcarrier들에 의한 side lobe 특성들을 제거하기 위 한 2개의 subcarrier를 추가하는 것이다. AIC의 단점 은 굉장히 높은 계산 복잡도에 있으며, 피하고자 하 는 대역폭이 넓을수록 계산 복잡도가 높아지고 notch 성능은 떨어지는 단점이 있다 [4] . …”

Section: -3 피 간섭 신호 검출 알고리즘 설계unclassified

A Detection Algorithm Study of the Victim Signal for the DAA Regulation in MB-OFDM UWB System

Shin¹,

Choi²

2009

The Journal of Korean Institute of Electromagnetic Engineering

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The purpose of this paper is to propose a detection algorithm and a tracking algorithm based on silent time using MB-OFDM UWB(Multi-Band Orthogonal Frequency Division Multiplexing Ultra Wide Band) receiver in order to satisfy DAA(Detect And Avoid) regulation of Korea to permit UWB in 3.1～4.8 GHz. In DAA regulation of Korea, if UWB device receives a signal more than -80 dBm/MHz from the victim system during UWB operation, the UWB system should avoid the collision within 2 sec. In this paper, we proposed the detection algorithm to detect the victim signal received by -80 dBm/MHz for the avoidance process that changes the operating UWB frequency to other UWB frequency and the subcarrier tracking algorithm to follow up the subcarrier positions of the victim signal for the tonenulling avoidance process that decreases the TX power of subcarriers occupied by the victim signal by -70 dBm/MHz.The performance of the detection algorithm and the tracking algorithm suggested in this paper is verified in simulation results considering various conditions.

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Low Complexity Active Interference Cancellation for OFDM Cognitive Radios

Cited by 13 publications

References 2 publications

An uplink resource allocation scheme for OFDMA‐based cognitive radio networks

An uplink resource allocation scheme for OFDMA‐based cognitive radio networks

A low complexity active interference cancellation method for OFDM based cognitive radios

A Detection Algorithm Study of the Victim Signal for the DAA Regulation in MB-OFDM UWB System

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