Granted patent by US Patent Office USTPO: Generalized Frequency Division Multiplexing Method with Multiple-Input Multiple-Output and Flexible Index Modulation


The demand for wireless access continues to grow with the new applications which create a broad range of technical challenges. Although orthogonal frequency division multiplexing (OFDM) with multiple numerologies concept will likely address the current technical challenges of fifth generation (5G) wireless networks, the sufficiency of OFDM-based physical layer (PHY) is quite disputable due to massive growth trend on the number of wireless users and applications for future wireless networks. Therefore, enhanced radio access technologies (RATs) are needed to fulfill the technical requirements of beyond 5G networks. Generalized frequency division multiplexing (GFDM), which has attracted tremendous attention over the past few years, comes into prominence by providing advantages in terms of out-of-band (OOB) emission, spectral efficiency and latency due to digitally pulse shaping of each subcarrier, reduced overhead of cyclic prefix and block-based structure, respectively. Index modulation (IM) techniques convey digital information by utilizing transmission entities in an innovative way and offer attractive advantages such as energy and spectral efficiency without increasing the computational complexity. On the other hand, multiple-input multiple-output (MIMO)-friendliness is a key ability for a PHY scheme to satisfactorily match the foreseen requirements of future wireless networks. Therefore, tight integration of GFDM with the MIMO and IM concepts has a strong potential to fulfill the foreseen requirements of future wireless networks in a satisfactory manner.

In this patent, innovative physical layer techniques have been studied to meet the technical requirements of Beyond 5G wireless networks. In this context, the issue of combining the Generalized Frequency Division Multiplexing (GFDM) with MIMO transmission and Index Modulation techniques has been discussed in depth. A GFDM-based flexible IM (FIM) transceiver, which is capable of generating and decoding various IM schemes has been proposed. Thanks to FIM, switching between different IM schemes to adapt the channel conditions can be possible using a single transceiver structure. FIM provides a multilayer transmission scheme by effectively using space, frequency, and time dimensions to adjust the BER performance and spectral efficiency, and enables to support different use-cases by using common space, frequency, and time resources at the same time. In the patent, new FIM-based transmitter-receiver structures are optimized in terms of energy efficiency, spectral efficiency, operational complexity and error performance.

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