OFDM for cognitive radio: merits and challenges

Mahmoud, Hisham; Yucek, T.; Arslan, Hüseyin

doi:10.1109/mwc.2009.4907554

Cited by 314 publications

(185 citation statements)

References 25 publications

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“…선형 조 건에서 FBMC는 가장 좋은 OOB 특성을 보인다 [14] . 즉, 스 펙트럼의 OOB가 매우 작아서 낭비되는 스펙트럼 영역이 줄고, 이로 인해 높은 스펙트럼 효율을 갖게 된다 [15] .…”

Section: -3 Fbmcunclassified

“…더욱이 FBMC는 OQAM(Offset Quadrature Amplitude Modulation) 변조를 사용하기 때문에 시스 그림 3. FBMC 송수신기의 구성도 템 복잡도가 향상되며, MIMO(Multiple Input Multiple Output) 기술과 같은 기존 기술과의 결합이 쉽지 않은 단점이 있다 [15] .…”

Section: -3 Fbmcunclassified

“…그림 4는 W-OFDM 시스템의 송수신기 구성을 나타낸 다. W-OFDM 시스템은 시간영역 윈도우 기법을 사용하 여 송신신호 스펙트럼의 OOB 전력을 저감시킨다 [15] . Table 3.…”

Section: -4 W-ofdmunclassified

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Comparison Analysis of Time and Frequency Resource of Candidate Waveforms for 5G Mobile Communications

An¹,

Ryu²

2016

The Journal of Korean Institute of Electromagnetic Engineering

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One of evaluation indicators of candidate waveforms for 5G mobile communication is spectral efficiency improvement by OOB(Out of Band) power reduction technique. In this paper, time-frequency resource allocation characteristic of UFMC(Universal Filtered MultiCarrier), FBMC(Filter Bank Multi-Carrier), and W-OFDM(Weighted Orthogonal Frequency Division Multiplexing) system is evaluated and analyzed. As simulation results, spectral efficiency characteristic of these systems have been improved according to time resource allocation. In this paper, we can confirm that each system has similar time-frequency efficiency characteristic when the number of transmission bit is same and four symbols are transmitted with the linear system condition. Also, we can conclude that FBMC system has the lowest time-frequency resource efficiency under the nonlinear condition.

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Section: -3 Fbmcunclassified

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Comparison Analysis of Time and Frequency Resource of Candidate Waveforms for 5G Mobile Communications

An¹,

Ryu²

2016

The Journal of Korean Institute of Electromagnetic Engineering

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“…In current wireless communication standards and services, MCM techniques are widely used due to its mitigation of multipath [13]. It is also very suitable for CR systems because it has the capability to monitor the PU spectral activity and flexibility to dynamically allocate unused licensed spectrum among SU subcarriers [14].…”

Section: Challenges Due To MCM Techniques In Cr Systemmentioning

confidence: 99%

Cognitive Radio Systems: Multicarrier Modulation and Power Allocation Challenges

Ahmed

Al-Imari²,

Xiao³

et al. 2014

J Elec Electron Syst

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“…From standards point of view, most of the cognitive radio-based standards have selected OFDM, or a variation of it, as their modulation scheme. The challenges of OFDM-based cognitive radio can be grouped into three categories, which are described in details in [5]. One of these categories is related to PAPR problem.…”

Section: Introductionmentioning

confidence: 99%

An Efficient Adaptive Technique with Low Complexity for Reducing PAPR in OFDM-Based Cognitive Radio

Sakran

Nasr

Shokair

2012

ISRN Signal Processing

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Cognitive radio (CR) is considered nowadays as a strong candidate solution for the spectrum scarcity problem. On standards level, many cognitive radio standards have chosen Non-Contiguous Orthogonal Frequency Division Multiplexing (NC-OFDM) as their modulation scheme. Similar to OFDM, NC-OFDM suffers from the problem of having a high Peak to Average Power Ratio (PAPR). If not solved, either the transmitted signal will be distorted, which will cause interference to primary (licensed) users, or the effeciency of the power amplifier will be seriously degraded. The effect of the PAPR problem in NC-OFDM based cognitive radio networks is worse than normal OFDM systems. In this paper, we propose enhanced techniques to reduce the PAPR in NC-OFDM systems. We start by showing that combining two standard PAPR reduction techniques (interleaver-based and selective mapping) results in a lower PAPR than using them individually. Then, an "adaptive number of interleavers" will be proposed that achieves the same performance of conventional interleaver-based PAPR reduction while reducing the CPU time by 41.3%. Finally, adaptive joint interleaver with selective mapping is presented, and we show that it gives the same performance as conventional interleaver-based technique, with reduction in CPU time by a factor of 50.1%.

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OFDM for cognitive radio: merits and challenges

Cited by 314 publications

References 25 publications

Comparison Analysis of Time and Frequency Resource of Candidate Waveforms for 5G Mobile Communications

Comparison Analysis of Time and Frequency Resource of Candidate Waveforms for 5G Mobile Communications

Cognitive Radio Systems: Multicarrier Modulation and Power Allocation Challenges

An Efficient Adaptive Technique with Low Complexity for Reducing PAPR in OFDM-Based Cognitive Radio

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