Unified Low Complexity Radix-2 Architectures for Time and Frequency-Domain GFDM Modem

Most of the conventional multicarrier waveforms explicitly or implicitly involve a generalized frequency division multiplexing (GFDM)-based modem as a core part of the baseband processing. Some are based on GFDM with a single prototype filter, e.g. orthogonal frequency division multiplexing (OFDM) and others employ multiple filters such as filter bank multicarrier (FBMC). Moreover, the GFDM degrees of freedom combined with multiple prototype filters design allow the development and optimization of new waveforms. Nevertheless, GFDM has been widely considered as a complex modulation because of the requirements of odd number of subcarriers or subsymbols. Accordingly, the current state of the art implementations consume high resources. One solution to reduce the complexity is utilizing radix-2 parameters. Due to the advancement in GFDM filter design, the constraint of using odd parameters has been overcome and radix-2 realization is now possible. In this paper, we propose a unified low complexity architecture that can be reconfigured to provide both time-domain and frequency-domain modulation/demodulation. The design consists of several radix-2 fast Fourier transform (FFT) and memory blocks, in addition to one complex multiplier. Moreover, we provide a unified architecture for the state of the art implementations, which is designed based on direct computation of circular convolution using parallel multiplier chains. As we demonstrate in this work, the FFT-based architecture is computationally more efficient, provides more flexibility, significantly reduces the resource consumption, and achieves similar latency for larger block size.

[1]  Helmut Bölcskei,et al.  Discrete Zak transforms, polyphase transforms, and applications , 1997, IEEE Trans. Signal Process..

[2]  Gerhard Fettweis,et al.  Generalized Frequency Division Multiplexing for 5th Generation Cellular Networks , 2014, IEEE Transactions on Communications.

[3]  Jason Wexler,et al.  Discrete Gabor expansions , 1990, Signal Process..

[4]  Robert M. Gray,et al.  Toeplitz and Circulant Matrices: A Review , 2005, Found. Trends Commun. Inf. Theory.

[5]  J.A.C. Bingham,et al.  Multicarrier modulation for data transmission: an idea whose time has come , 1990, IEEE Communications Magazine.

[6]  J. Tukey,et al.  An algorithm for the machine calculation of complex Fourier series , 1965 .

[7]  Gerhard Fettweis,et al.  Precoded GFDM transceiver with low complexity time domain processing , 2016, EURASIP J. Wirel. Commun. Netw..

[8]  Frank Schaich,et al.  5G air interface design based on Universal Filtered (UF-)OFDM , 2014, 2014 19th International Conference on Digital Signal Processing.

[9]  Geoffrey Ye Li,et al.  OFDM and Its Wireless Applications: A Survey , 2009, IEEE Transactions on Vehicular Technology.

[10]  Linda Doyle,et al.  Low complexity GFDM receiver design: A new approach , 2015, 2015 IEEE International Conference on Communications (ICC).

[11]  Gerhard Fettweis,et al.  Optimal Radix-2 FFT Compatible Filters for GFDM , 2017, IEEE Communications Letters.

[12]  Gerhard Fettweis,et al.  GFDM - A Framework for Virtual PHY Services in 5G Networks , 2015, ArXiv.

[13]  A. Robert Calderbank,et al.  Orthogonal Time Frequency Space Modulation , 2017, 2017 IEEE Wireless Communications and Networking Conference (WCNC).

[14]  Alfred Fe.  MULTIDIMENSIONAL WAVE-DIGITAL PRINCIPLES: FROM FILTERING TO NUMERICAL INTEGRATION , 1994 .

[15]  Daniel Roviras,et al.  WOLA processing: A useful tool for windowed waveforms in 5G with relaxed synchronicity , 2017, 2017 IEEE International Conference on Communications Workshops (ICC Workshops).

[16]  I. Daubechies,et al.  Gabor Time-Frequency Lattices and the Wexler-Raz Identity , 1994 .

[17]  Behrouz Farhang-Boroujeny,et al.  OFDM Versus Filter Bank Multicarrier , 2011, IEEE Signal Processing Magazine.

[18]  Gerhard Fettweis,et al.  Frequency-Shift Offset-QAM for GFDM , 2015, IEEE Communications Letters.

[19]  Frank Schaich,et al.  5GNOW: non-orthogonal, asynchronous waveforms for future mobile applications , 2014, IEEE Communications Magazine.

[20]  Evangelos Eleftheriou,et al.  Filtered multitone modulation for very high-speed digital subscriber lines , 2002, IEEE J. Sel. Areas Commun..

[21]  Gerhard Fettweis,et al.  A study on the physical layer performance of GFDM for high throughput wireless communication , 2017, 2017 25th European Signal Processing Conference (EUSIPCO).

[22]  Ajem Guido Janssen,et al.  Signal Analytic Proofs of Two Basic Results on Lattice Expansions , 1994 .

[23]  Gilberto Berardinelli,et al.  Zero-tail DFT-spread-OFDM signals , 2013, 2013 IEEE Globecom Workshops (GC Wkshps).

[24]  Gerhard Fettweis,et al.  Generalized Frequency Division Multiplexing in a Gabor Transform Setting , 2014, IEEE Communications Letters.

[25]  Fredrik Berggren,et al.  N-continuous OFDM , 2009, IEEE Communications Letters.

[26]  Gerhard Fettweis,et al.  Low Complexity GFDM Receiver Based on Sparse Frequency Domain Processing , 2013, 2013 IEEE 77th Vehicular Technology Conference (VTC Spring).

[27]  Gerhard Fettweis,et al.  Flexible GFDM Implementation in FPGA with Support to Run-Time Reconfiguration , 2015, 2015 IEEE 82nd Vehicular Technology Conference (VTC2015-Fall).