Optimal Radix-2 FFT Compatible Filters for GFDM

Nimr, Ahmad; Matthé, Maximilian; Zhang, Dan; Fettweis, Gerhard

doi:10.1109/lcomm.2017.2687926

Cited by 25 publications

(19 citation statements)

References 13 publications

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“…Further details concerning the observed signal y cyclic,q can be found in the Appendix where we provide an algebraic proof that y cyclic,q experiences a circular channel matrix. In (26) and the rest of expressions in this section, the subscript b is ignored for brevity. Also note that in (26), the first L samples of the y cyclic,q are subject to noise variance 2σ 2 w , and therefore, if an N d point FFT size has been utilized, some noise correlation occurs in frequency domain.…”

Section: A Uw-free Equalizationmentioning

confidence: 99%

On UW-Based Transmission for MIMO Multi-Carriers With Spatial Multiplexing

Ehsanfar

Chafii

Fettweis

2020

IEEE Trans. Wireless Commun.

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In this paper, we design a frame structure for unique word (UW) based transmission of multiple-input-multiple-output (MIMO) systems under doubly-dispersive wireless channel conditions. We elaborate an energy and spectral efficiency analysis of a MIMO UW-based system vs. a conventional MIMO cyclic prefix (CP)-based system. Considering the UW-based transmission for a MIMO multi-carrier, we derive its signal processing algorithms for channel estimation and joint channelequalization-and-demodulation. Through theoretical derivations as well as extensive simulations, we show that the proposed MIMO UW-based system significantly outperforms the state-ofthe-art approaches. I. INTRODUCTION T OWARDS the sixth generation (6G) cellular networks, new applications and use-cases are being enabled for the vertical markets, while also new challenges for a holistic approach and more efficient service provisioning are being defined. Thanks to the flexible physical layer definitions in latest release of fifth generation (5G) New Radio (NR) [1], diverse services namely enhanced-mobile-broadband, ultrareliable-low-latency-communication, and massive machinetype-communication are envisioned to coexist within the same time interval and the same frequency band. A major advancement for realizing this coexistence is the massive multipleinput multiple-output (MIMO) technology which can be used for three key concepts, i.e., beamforming, spatial diversity and spatial multiplexing. While employing the MIMO technology for spatial diversity or spatial multiplexing, the mobility of the users becomes limited because a large number of channel parameters requires a long training sequence that together with the data packet, must fit within the channel coherence time. Unique-word (UW) transmission is a promising candidate that facilitates per-block synchronization and channel estimation [2], [3], [4]. The main concept is to replace the cyclic prefix (CP) of random nature by a deterministic sequence that is known to both transmitter and receiver. Hence, maintaining the advantages of CP in terms of robustness against multipath channels, UW allows fast channel tracking in highly mobile Manuscript

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Section: A Uw-free Equalizationmentioning

confidence: 99%

On UW-Based Transmission for MIMO Multi-Carriers With Spatial Multiplexing

Ehsanfar

Chafii

Fettweis

2020

IEEE Trans. Wireless Commun.

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“…For example, when FBMC is applied for opportunistic spectrum sharing, in order to avoid interfering with other bands, well localized filters in time and frequency are prone to be designed to minimize Out of Band [140]. Similarly, there are also some optimization based methods for different waveform candidates, for example, OFDM [154], FBMC [140,155,156], GFDM [158][159][160][161], UFMC [162,163]. In general, the establishment and constraints imposed on objective functions are often highly non-linear, which increases the computational complexity and also sensitive to the selection of initial values.…”

Section: Optimization Based Methodsmentioning

confidence: 99%

An Overview of FIR Filter Design in Future Multicarrier Communication Systems

et al. 2020

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Future wireless communication systems are facing with many challenges due to their complexity and diversification. Orthogonal frequency division multiplexing (OFDM) in 4G cannot meet the requirements in future scenarios, thus alternative multicarrier modulation (MCM) candidates for future physical layer have been extensively studied in the academic field, for example, filter bank multicarrier (FBMC), generalized frequency division multiplexing (GFDM), universal filtered multicarrier (UFMC), filtered OFDM (F-OFDM), and so forth, wherein the prototype filter design is an essential component based on which the synthesis and analysis filters are derived. This paper presents a comprehensive survey on the recent advances of finite impulse response (FIR) filter design methods in MCM based communication systems. Firstly, the fundamental aspects are examined, including the introduction of existing waveform candidates and the principle of FIR filter design. Then the methods of FIR filter design are summarized in details and we focus on the following three categories—frequency sampling methods, windowing based methods and optimization based methods. Finally, the performances of various FIR design methods are evaluated and quantified by power spectral density (PSD) and bit error rate (BER), and different MCM schemes as well as their potential prototype filters are discussed.

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“…In the packet format that is shown in Figure , M =2 is considered for the training block, ie, the preamble, to reduce the overhead it imposes to the system, and according to our transceiver filters, odd values of M are considered for the payload. Furthermore, as shown in the work of Nimr et al, with proper filter design, even values of M can be used for the payload. To lower the CFO estimation complexity, we propose to utilize the same ZC training sequence on both symbols in the preamble to make the matrix X H X in diagonal.…”

Section: Proposed Joint Cfo and Channel Estimationmentioning

confidence: 99%

Maximum‐likelihood synchronization and channel estimation with multiuser detection in GFDMA

Shayanfar

Saeedi-Sourck

Farhang

et al. 2018

Trans Emerging Tel Tech

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Accurate estimation and correction of channel distortions and carrier frequency offset (CFO) are of a great importance in any multicarrier communication system. Hence, in this paper, we propose data‐aided CFO and channel estimation techniques for both multiuser uplink and downlink of the generalized frequency division multiple access (GFDMA). Our proposed solutions jointly estimate the CFO and channel responses based on the maximum‐likelihood criterion. To simplify the implementation of the proposed estimation algorithms, we suggest a preamble composed of two similar Zadoff‐Chu training sequences in a generalized frequency division multiplexing block. It is worth mentioning that our proposed technique can estimate both integer and fractional CFO values without any limitation on the acquisition range of CFO. In the uplink phase, each user aligns its carrier frequency with the base station using the estimated CFO in the downlink. However, the CFO estimates may get outdated for the uplink transmission. Thus, residual CFOs may still remain in the received signal at the base station. While being trivial in the downlink, CFO correction is a challenging task in the uplink. Thus, we also propose a joint CFO correction and channel equalization technique for the uplink of GFDMA systems. Finally, we evaluate our proposed estimation and correction algorithms in terms of estimation mean square error and bit error rate performance through simulations.

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Optimal Radix-2 FFT Compatible Filters for GFDM

Cited by 25 publications

References 13 publications

On UW-Based Transmission for MIMO Multi-Carriers With Spatial Multiplexing

On UW-Based Transmission for MIMO Multi-Carriers With Spatial Multiplexing

An Overview of FIR Filter Design in Future Multicarrier Communication Systems

Maximum‐likelihood synchronization and channel estimation with multiuser detection in GFDMA

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