Spectral Encapsulation to Block the Out-of-Band Emission of OFDM Signals for Future Communications

Kim, Myung-Sup; Kwak, Dae‐Young; Jung, Ji-Won; Kim, Ki-Man; Kim, Wan-Jin

doi:10.1109/vtc2020-spring48590.2020.9129421

Cited by 3 publications

(6 citation statements)

References 4 publications

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“…The time domain representation of Ψ is obtained through IDFT as (15) From Appendix D, we have Therefore, it can be seen that the approximated matrix of X is Hermitian and diagonal. Figure 3 shows the exact diagonal elements by ( 16) and the approximate diagonal elements by (26). The two dotted curves are in good agreement, confirming that ( 26) is close to (16).…”

Section: Restorationsupporting

confidence: 54%

See 1 more Smart Citation

Spectrally encapsulated OFDM: Vectorized structure with minimal complexity

Kim¹,

Kwak

Jung

et al. 2021

ETRI Journal

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To efficiently use frequency resources, the next 6th generation mobile communication technology must solve the problem of out‐of‐band emission (OoBE) of cyclic prefix (CP) orthogonal frequency division multiplexing (OFDM), which is not solved in 5th generation technology. This study describes a new zero insertion technique to replace an existing filtering scheme to solve this internal problem in OFDM signals. In the development of the proposed scheme, a precoder with a two‐dimensional structure is first designed by generating a two‐dimensional mapper and using the specialty of each matrix. A spectral shaping technique based on zero insertion instead of a long filter is proposed, so it can be applied not only to long OFDM symbols, but also very short ones. The proposed method shows that the transmitted signal is completely blocked at the bandwidth boundaries of signals according to the current standards, and it is confirmed that the proposed scheme is ideal with respect to bit error rate (BER) performance because its BER is the same as that of CP‐OFDM. In addition, the proposed scheme can transformed into a real time structure through vectorizing process with minimal complexity.

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Section: Restorationsupporting

confidence: 54%

“…Recently, a technique for completely preventing out-ofband power emission, which is a core technology of future wireless communication technology, has been proposed [25,26]. This technique covered the spectral encapsulation (SE) OFDM technique based on three main techniques: windowing, zero insertion, and orthogonalization.…”

mentioning

confidence: 99%

Spectrally encapsulated OFDM: Vectorized structure with minimal complexity

Kim¹,

Kwak

Jung

et al. 2021

ETRI Journal

Self Cite

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show abstract

“…Therefore, using

A_{o}

may be more convenient than using

A^{+}

to estimate the bandwidth of the matrix. Meanwhile, the nearest orthogonal matrix

A_{⊥}

boldA

can be obtained directly by the following equation [27]:

A_{⊥} = boldA {({boldA}^{normalT} A)}^{- \frac{1}{2}} .

Latter matrix

{({boldA}^{normalT} A)}^{- 1 / 2}

serves to change the eigenvalues of previous matrix

boldA

to 1, and Equation (35) becomes

A_{⊥} = U_{A} ([], \begin{matrix} boldI \\ bold0 \end{matrix}) V_{A}^{T},

where the sizes of

boldI

and

bold0

are

M \times M

and

((), N - M) \times M

, respectively. Evidently, matrix

A_{⊥}

is an orthogonal matrix.…”

Section: Erasing the Entriesmentioning

confidence: 99%

“…A technology that can completely prevent out-of-band power emission, which is the core technology of future wireless communication technology, has been proposed recently [25,26]. These technologies developed spectrum encapsulation (SE)-OFDM based on three major technologies, namely, windowing, zero insertion, and orthogonalization, and implementation complexity was drastically reduced through vectorization [27]. Despite the maturity of the technology for blocking the OoBE of OFDM, whether it will continue to be used as a technology in the future remains questionable.…”

Section: Introductionmentioning

confidence: 99%

Least squares decoding in binomial frequency division multiplexing

2023

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This paper proposes a method that can reduce the complexity of a system matrix by analyzing the characteristics of a pseudoinverse matrix to receive a binomial frequency division multiplexing (BFDM) signal and decode it using the least squares (LS) method. The system matrix of BFDM can be expressed as a band matrix, and as this matrix contains many zeros, its amount of calculation when generating a transmission signal is quite small. The LS solution can be obtained by multiplying the received signal by the pseudoinverse matrix of the system matrix. The singular value decomposition of the system matrix indicates that the pseudoinverse matrix is a band matrix. The signal-tointerference ratio is obtained from their eigenvalues. Meanwhile, entries that do not contribute to signal generation are erased to enhance calculation efficiency. We decode the received signal using the pseudoinverse matrix and the removed pseudoinverse matrix to obtain the bit error rate performance and to analyze the difference.

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“…9, one can grasp that OFDM owns the worst worst PSD. To deal with, a spectral encapsulation is introduced in [65] to shape the spectrum of OFDM.…”

Section: A Power Spectral Densitymentioning

confidence: 99%

Prototype Filters and Filtered Waveforms for Radio Air-Interfaces: A Review

Bendimerad,

Senhadji,

Bendimerad

2021

Preprint

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The perspective for the next generation of wireless communications prognosticates that the communication should take place with high heterogeneity in terms of services and specifications. The emergence of new communication networks, especially between devices like internet of things (IoT) networks, machine type communications (MTC) and unmanned aerial vehicles (UAV), makes the redesign of the radio air-interfaces even higher significant. High data rate, efficient use of the spectrum, low latency, flexibility, scalable ability, energy efficiency and reduced complexity are in the vanguard of the challenging needs. This highlights the necessity to overrides classical waveforms and propose new air interface that best fits these requirements. Several attempts were conducted to propose the most suitable prototype filters and their associated waveforms that support the future applications with these crucial prerequisites. In the present paper, we analyze the most important marked prototype filters reported in literature, and their corresponding waveforms proposed as prominent candidates for wireless air interface. We will show that the filter properties impact the waveform performances and that a close filter-waveform interrelationship is there. The principal contribution is to give a deep insight on the structure of these filters and waveforms and to come up with a fair comparison regarding different criteria and distinct figures of merit.

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Spectral Encapsulation to Block the Out-of-Band Emission of OFDM Signals for Future Communications

Cited by 3 publications

References 4 publications

Spectrally encapsulated OFDM: Vectorized structure with minimal complexity

Spectrally encapsulated OFDM: Vectorized structure with minimal complexity

Least squares decoding in binomial frequency division multiplexing

Prototype Filters and Filtered Waveforms for Radio Air-Interfaces: A Review

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