TURBO CODED OFDM-OQAM USING HILBERT TRANSFORM Kasturi Vasudevan1; 1IIT KANPUR, Kanpur, India; PAPER: 334/AdvancedMaterials/Regular (Oral) OS SCHEDULED: 11:30/Thu. 30 Nov. 2023/Heliconia ABSTRACT: Orthogonal frequency division multiplexing (OFDM) with offset quadrature amplitude modulation (OQAM) has been widely discussed in the literature and is considered a popular waveform for 5th generation (5G) wireless telecommunications and beyond. In this work, we show that OFDM-OQAM can be generated using the Hilbert transform and is equivalent to single sideband modulation (SSB), that has roots in analog telecommunications [1]. The symbol density in time-frequency space is greater than unity. OFDM-OQAM is also known as filter bank multicarrier (FBMC). One of the key advantages of OFDM-OQAM/FBMC over OFDM [2, 3, 4] is its immunity against frequency offsets. In other words, it may not be necessary for an OFDM-OQAM/FBMC system to estimate and cancel the frequency offset, unlike OFDM. The other important feature of OFDM-OQAM is the spectral containment of each subcarrier using a transmit filter, which is absent in OFDM. However, OFDM is more attractive than OFDM-OQAM in terms of implementation simplicity.
The transmit filter for OFDM-OQAM is complex valued and is given by References: [1] K Vasudevan, Gyanesh Kumar Pathak, Surendra Kota and Lov Kumar, “OFDM-OQAM using the Hilbert Transform”, Invited Talk, WCAM-2023, 8 – 10 May, Tokyo, Japan.<br />[2] K Vasudevan, “Coherent Detection of Turbo Coded OFDM Signals Transmitted through Frequency Selective Rayleigh Fading Channels”, IEEE International Conference on Signal Processing Computing and Control, 26—28 Sept. 2013, Shimla.<br />[3] K Vasudevan, “Coherent Detection of Turbo-Coded OFDM Signals Transmitted Through Frequency Selective Rayleigh Fading Channels with Receiver Diversity and Increased Throughput”, Wireless Personal Communications, Springer, vol. 82, no. 3, pp. 1623—1642, June 2015.<br />[4] K Vasudevan, “Near Capacity Signaling over Fading Channels using Coherent Turbo Coded OFDM and Massive MIMO”, International Journal On Advances in Telecommunications, issn 1942-2601, vol. 10, no. 1 & 2, year 2017, 22:37, http://www.iariajournals.org/telecommunications/. |