Suppression of sidelobes in OFDM systems by multiple‐choice sequences

Cosovic, I.; Mazzoni, T.

doi:10.1002/ett.1162

Cited by 88 publications

(50 citation statements)

References 9 publications

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“…The parameters at the receiver can be set accordingly. A straightforward method called multiplechoice sequence (MCS) is proposed in [20]. The data symbol is element-wise produced by a set of vectors.…”

Section: Techniques Represented By the Symbol Mappingmentioning

confidence: 99%

Out-of-band emission suppression techniques based on a generalized OFDM framework

You

Fang

2014

EURASIP J. Adv. Signal Process.

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Orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) systems suffer from the large out-of-band emission (OOBE) that may interfere with other users. Since most existing OFDM OOBE suppression schemes are derived on the base of an original OFDM system without any other scheme, we first propose a generalized OFDM framework that is capable of describing these schemes no matter whether any one or more of the schemes is applied. Then, according to the place where these schemes are implemented in our framework, they are classified into three groups, namely symbol mapping techniques, precoding techniques, and time-domain techniques. Finally, based on the proposed framework, we propose three new schemes by combining a precoding scheme named singular value decomposition (SVD) precoding with three other schemes from the three groups, namely spectral precoding, N-continuous symbol mapping, and filtering. Numerical results show the power spectral density (PSD), peak-to-average power ratio (PAPR), and bit error rate (BER) performances of the three proposed schemes. Since the individual schemes have complementary characteristics, the three proposed combined schemes are constructed to maintain the merits and avoid the drawbacks of the individual schemes involved. Thus, it is demonstrated that the proposed framework can be employed to develop other new combined OOBE suppression schemes tailoring to some specific practical needs.

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Section: Techniques Represented By the Symbol Mappingmentioning

confidence: 99%

Out-of-band emission suppression techniques based on a generalized OFDM framework

You

Fang

2014

EURASIP J. Adv. Signal Process.

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“…From this set, the sequence which offers the maximum reduction of out-of-band radiation is chosen for the actual transmission. These two approaches are discussed thoroughly in [Mahmoud & Arsalan, 2008a;Cosovic & Mazzoni, 2006] respectively. Note that in [Ghassemi et al 2010], a generalization of the multiple choice sequences method has been proposed that reduces OOB and PAPR jointly.…”

Section: State-of-the-artmentioning

confidence: 99%

Partial Response Signaling: A Powerful Tool for Spectral Shaping in Cognitive Radio Systems

Naghsh¹,

Omidi²

2012

Foundation of Cognitive Radio Systems

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“…Since the data subcarriers are perturbed, this approach has the side effect of increasing the bit-error-rate (BER) of the system [7]. In [8], the multiple choice sequences (MCS) approach is introduced to reduce the sidelobes of OFDM subcarriers. In MCS approach, the original data sequence is transformed into a set of sequences and the sequence with minimum sidelobe power is used for transmission.…”

Section: Introductionmentioning

confidence: 99%

“…In MCS approach, the original data sequence is transformed into a set of sequences and the sequence with minimum sidelobe power is used for transmission. Since the transmitted sequence needs to be mapped back to the original sequence, some side information needs to be sent to the receiver, thereby reducing the effective data rate [8]. In the active interference cancellation (AIC) technique [9], few subcarriers are reserved and weighted and are inserted in the PU band and at the edges of PU band to suppress the sidelobes, whereas in the adaptive symbol transition (AST) method [10], this is achieved by optimally extending the time domain symbols to reduce http://journals.uob.edu.bh the sidelobes.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Out of Band Radiation Using Modified Constellation Expansion in OFDM based Cognitive Radio

Malik¹

2016

IJCNT

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Abstract:Out of band radiation (OOBR) is one of the major problems in OFDM based Cognitive Radios. In the spectrum sharing scenario, OOBR generates appreciable interference to the primary user, even if its spectrum band is not used. The basic cause of this OOBR is the rectangular shaped OFDM symbol. To mitigate the effects of the OOBR, a number of techniques have been proposed in the literature. These techniques shape the OFDM symbol either in time or in frequency domain. Time domain techniques achieve OOBR reduction by using smoother windows. But this reduces the overall throughput of the system. In frequency domain techniques, some of the subcarriers are either used as guard band or reserved for interference cancellation. These subcarriers do not carry any data and as such reduce the spectral efficiency of the system. In this paper, we use different variants of Constellation expansion (CE) technique to reduce OOBR. CE techniques do not suffer from throughput reduction or spectral efficiency loss, as the original symbols are mapped to a higher order constellation set and the symbol sequence is replaced by a new sequence that produces minimum OOBR. We study different mapping techniques based on single bit or two bit mapping of CE technique. We show through simulations that two bit mapping of CE technique gives appreciable improvement over the basic CE technique.

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Suppression of sidelobes in OFDM systems by multiple‐choice sequences

Cited by 88 publications

References 9 publications

Out-of-band emission suppression techniques based on a generalized OFDM framework

Out-of-band emission suppression techniques based on a generalized OFDM framework

Partial Response Signaling: A Powerful Tool for Spectral Shaping in Cognitive Radio Systems

Reduction of Out of Band Radiation Using Modified Constellation Expansion in OFDM based Cognitive Radio

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