Abstract
Clear communication over wireless channels demands overcoming their disruptive effects. Doubly-selective fading channels, with rapidly changing parameters, pose a particular challenge for accurate channel estimation. Traditional models often falter, lacking solutions or becoming overly complex. This is where deep learning takes center stage. In OFDM systems, pilots assist in estimating the channel response, but they also come at the cost of reduced data throughput. Adaptive adjustment of pilot patterns based on the channel state offers a promising solution. This paper introduces a deep learning-based framework that leverages adaptive pilots for fast-varying channels. We employ two deep neural networks. First, the pilot adaptation network dynamically selects the pilot pattern, reacting to the channel coherence bandwidth. Second, the channel estimation network extracts features from the channel frequency response using a 1D convolutional neural network. It then harnesses the power of long short-term memory layers to learn the channel behavior and estimate the response across all pilots and data subcarriers. Training and testing datasets are generated using WINNER II. The entire communication link, equipped with our proposed method, undergoes rigorous simulations, evaluated by both bit error rate and pilot overhead. The simulation results illustrate that the proposed scheme outperforms the previous methods, because it yields the same or better errors with less pilot overhead. This translates to a substantial data rate boost, paving the way for faster wireless communication.
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Data Availability
The data that support the findings of this study are not openly available and are available from the corresponding author upon reasonable request.
Code Availability
The channel dataset is generated by WINNER II. The deep neural networks are trained in Python using Keras and exported to MATLAB, where the overall link is simulated. All codes are available from the corresponding author upon request.
References
Garcia, M., Molina-Galan, A., Boban, M., Gozalvez, J., Coll-Perales, B., Sahin, T., & Kousaridas, A. (2021). A tutorial on 5G NR V2X communications. IEEE Communication Surveys and Tutorials, 23(3), 1972–2026. https://doi.org/10.1109/COMST.2021.3057017
Mizmizi, M., Tagliaferri, D., Badini, D., Mazzucco, C., & Spagnolini, U. (2021). Channel estimation for 6G V2X hybrid systems using multi-vehicular learning. IEEE Access, 9, 95775–95790. https://doi.org/10.1109/ACCESS.2021.3095121
Jiang, H., Mukherjee, M., Zhou, J., & Lloret, J. (2021). Channel modeling and characteristics for 6G wireless communications. IEEE Network, 35(1), 296–303. https://doi.org/10.1109/MNET.011.2000348
Wang, J., Zhang, W., & Chen, Y. (2022). Time-varying channel estimation scheme for uplink MU-MIMO in 6G systems. IEEE Transactions on Vehicular Technology, 71(11), 11820–11831. https://doi.org/10.1109/TVT.2022.3192902
Coleri, S., Ergen, M., Puri, A., & Bahai, A. (2002). Channel estimation techniques based on pilot arrangement in OFDM systems. IEEE Transactions on Broadcasting, 48(3), 223–229. https://doi.org/10.1109/TBC.2002.804034
Pradhan, P. K., Patra, S. K., Faust, O., & Chua, B. K. (2012). Channel estimation algorithms for OFDM systems. International Journal of Signal and Imaging Systems Engineering, 5(4), 267–273.
Liu, Y., Tan, Z., Hu, H., Cimini, L., & Ye Li, G. (2014). Channel estimation for OFDM. IEEE Communication Surveys and Tutorials, 16(4), 1891–1908. https://doi.org/10.1109/COMST.2014.2320074
Elbadri, O., & Elbarsha, A. (2016). Kalman-filter channel estimator for OFDM system in time-varying channel. University of Benghazi-Al-Adab Journal, 23, 92–95.
O’Shea, T., & Hoydis, J. (2017). An introduction to deep learning for the physical layer. IEEE Transactions on Cognitive Communication Networks, 3(4), 563–575. https://doi.org/10.1109/TCCN.2017.2758370
O’Shea, T., Karra, K., & Clancy, TC. (2017). Learning approximate neural estimators for wireless channel state information. In: IEEE 27th international workshop on machine learning for signal processing (MLSP). https://doi.org/10.1109/MLSP.2017.8168144
Ye, H., Li, G., & Juang, B. (2018). Power of deep learning for channel estimation and signal detection in OFDM systems. IEEE Wireless Communications Letters, 7(1), 114–117. https://doi.org/10.1109/LWC.2017.2757490
Kyösti, P., Meinilä, J., Hentilä, L., Zhao, X., Jämsä, T., Schneider, C., Narandzić, M., Milojević, M., Hong, A., Ylitalo, J., Holappa, V. M., Alatossava, M., Bultitude, R., de Jong, Y., & Rautiainen, T. (2008). WINNER II channel models. IST-4–027756 WINNER II D1.1.2 V1.2.
Neumann, D., Wiese, T., & Utschick, W. (2018). Learning the MMSE channel estimator. IEEE Transactions on Signal Processing, 66(11), 2905–2917. https://doi.org/10.1109/TSP.2018.2799164
He, H., Wen, C., Jin, S., & Li, G. (2018). Deep learning-based channel estimation for beamspace mmWave massive MIMO systems. IEEE Wireless Communication Letters, 7(5), 852–855. https://doi.org/10.1109/LWC.2018.2832128
Gu, J., Shan, C., Chen, X., Yin, H., & Wang, W. (2018). A novel pilot-aided channel estimation scheme based on RNN for FDD-LTE systems. In: 10th international conference on wireless communications and signal processing (WCSP). https://doi.org/10.1109/WCSP.2018.8555634
Gao, X., Jin, S., Wen, C., & Li, G. (2018). ComNet: Combination of deep learning and expert knowledge in OFDM receivers. IEEE Communications Letters, 22(12), 2627–2630. https://doi.org/10.1109/LCOMM.2018.2877965
Soltani, M., Pourahmadi, V., Mirzaei, A., & Sheikhzadeh, H. (2019). Deep learning-based channel estimation. IEEE Communications Letters, 23(4), 652–655. https://doi.org/10.1109/LCOMM.2019.2898944
Zhang, J., He, H., Wen, C., Jin, S., & Li, G. (2019). Deep learning based on orthogonal approximate message passing for CP-free OFDM. In: 2019 IEEE international conference on acoustics, speech and signal processing (ICASSP). https://doi.org/10.1109/ICASSP.2019.8682639
Liao, Y., Hua, Y., Dai, X., Yao, H., & Yang, X. (2019). ChanEstNet: A deep learning-based channel estimation for high-speed scenarios. In: 2019 IEEE international conference on communications (ICC). https://doi.org/10.1109/ICC.2019.8761312
Ponnaluru, S., & Penke, S. (2020). Deep learning for estimating the channel in orthogonal frequency division multiplexing systems. Journal of Ambient Intelligence and Humanized Computing, 12, 5325–5336. https://doi.org/10.1007/s12652-020-02010-1
Jebur, B., Alkassar, S., Abdullah, M., & Tsimenidis, C. (2021). Efficient machine learning-enhanced channel estimation for OFDM systems. IEEE Access, 9, 100839–100850. https://doi.org/10.1109/ACCESS.2021.3097436
Shi, Q., Liu, Y., Zhang, S., Xu, S., & Lau, V. (2021). A unified channel estimation framework for stationary and non-stationary fading environments. IEEE Transactions on Communications, 69(7), 4937–4952. https://doi.org/10.1109/TCOMM.2021.3072726
Li, Y., Hu, Y., Min, K., Park, H., Yang, H., Wang, T., & Zhang, C. J. (2023). Artificial Intelligence augmentation for channel state information in 5G and 6G. IEEE Wireless Communications Magazine, 30(1), 104–110. https://doi.org/10.1109/MWC.005.2200245
Nguyen, C., Hoang, T., & Cheema, A. (2023). Channel estimation using CNN-LSTM in RIS-NOMA assisted 6G network. IEEE Transactions on Machine Learning in Communications and Networking, 1, 43–60. https://doi.org/10.1109/TMLCN.2023.3278232
Kim, W., Ahn, Y., Kim, J., & Shim, B. (2023). Towards deep learning-aided wireless channel estimation and channel state information feedback for 6G. Journal of Communications and Networks, 25(1), 61–75. https://doi.org/10.23919/JCN.2022.000037
Simeone, O., & Spagnolini, U. (2004). Adaptive pilot pattern for OFDM systems. In: 2004 IEEE international conference on communications (ICC). https://doi.org/10.1109/ICC.2004.1312647
Byun, J., & Natarajan, N. (2009). Adaptive pilot utilization for OFDM channel estimation in a time varying channel. In: IEEE 10th annual wireless and microwave technology conference. https://doi.org/10.1109/WAMICON.2009.5207292
Rezgui, C., & Grayaa, K. (2016). An enhanced channel estimation technique with adaptive pilot spacing for OFDM system. In: 2016 international symposium on networks, computers and communications (ISNCC). https://doi.org/10.1109/ISNCC.2016.7746098
Rao, R., Marojevic, V., & Reed, J. (2018). Adaptive pilot patterns for CA-OFDM systems in nonstationary wireless channels. IEEE Transactions on Vehicular Technology, 67(2), 1231–1244. https://doi.org/10.1109/TVT.2017.2751548
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Shahmohammadi, M., Sebghati, M. & Zareian, H. Deep Learning-based Pilot Adaptation and Channel Estimation in OFDM Systems. Wireless Pers Commun 134, 915–933 (2024). https://doi.org/10.1007/s11277-024-10937-3
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DOI: https://doi.org/10.1007/s11277-024-10937-3