LSTM-Based Channel Estimation For OTFS Modulation

This project presents codes for the LS-LSTM-NN channel estimation affected by HPA impairments proposed for OTFS channels in "LSTM-Based Time-Frequency Domain Channel Estimation for OTFS Modulation".

This project presents:

• The SFFT-based OTFS Tx-Rx implementation with the TCE [1] channel estimation: Communication scenario provided in Matlab

- The full training and testing phases LS-LSTM-NN channel estimators proposed: LSTM network implementation provided in Python

The following instructions will guide the execution: 1) MatlabCodes/mainOTFSCENLD.m: Present the main simulation file. The user needs to define the simulation parameters (Speed, channel model, modulation order, HPA IBO, [...]). This file will obtain the results for the benchmark TCE estimation [1] and save the datasets for the initial LS estimation used in the proposed method. 2) MatlabCodes/DatasetsGenerationNLD: The testing and training datasets are generated in the path PythonCodes - NLD 3) PythonCodes/LSTMTraining.py: The LSTM-NN training is performed by employing the training dataset. 500 models are saved and considered as average (in order to obtain reproducible results) in the next step. 4) Pythoncodes/LSTMAvgModel: The latest 50 trained models are averaged. 5) PythonCodes/LSTMTesting.py: The LSTM-NN model is tested by considering the testing datasets, and the results are saved in .mat files. 6) MatlabCodes/ResultsProcessingNLD: Results from Python are processed and saved 7) MatlabCodes/Plotting[...]: Results are plotted in the different metrics

Additional files: - MatlabCodes/OTFSfunctions.m: Includes functions for SFFT-based OTFS transmission. - MatlabCodes/Channelfunctions.m: Includes the pre-defined vehicular channel models [2] for different mobility conditions. - Matlabcodes/[NLD;hpasaleh;functionHPAWONG5Poly;charachpa;]: Files related to the Memoryless Polynomial HPA described in [3].

- Matlab_codes/circulant: Used to obtain the circulant matrix in the TCE method.

[1] P. Raviteja, K. T. Phan, and Y. Hong, “Embedded pilot-aided channel estimation for OTFS in delay–doppler channels,” IEEE Transactions on Vehicular Technology, vol. 68, no. 5, pp. 4906–4917, 2019

[2] G. Acosta-Marum and M. A. Ingram, ‘‘Six time- and frequency-selective empirical channel models for vehicular wireless LANs,’’ IEEE Veh. Technol. Mag., vol. 2, no. 4, pp. 4–11, Dec. 2007.

[3] H. Shaiek, R. Zayani, Y. Medjahdi, and D. Roviras, “Analytical analysis of SER for beyond 5G post-OFDM waveforms in presence of high power amplifiers,” IEEE Access, vol. 7, pp. 29 441–29 452, 201.