Is Synchronization a Bottleneck for Pilot-Assisted URLLC Links? (2401.09089v2)
Abstract: We propose a framework to evaluate the so-called random-coding union bound with parameter $s$ (RCUs) on the achievable error probability in the finite-blocklength regime for a pilot-assisted transmission scheme operating over an imperfectly synchronized and memoryless block-fading waveform channel. Unlike previous results, which disregard the effects of imperfect synchronization, our framework utilizes pilots for both synchronization and channel estimation. Specifically, we provide an algorithm to perform joint synchronization and channel estimation, and verify its accuracy by observing its tightness in comparison with the Cramer-Rao bound. Then, we develop an RCUs bound on the error probability, which applies for a receiver that treats the estimates provided by the algorithm as accurate. Additionally, we utilize the saddlepoint approximation to provide a numerically efficient method for evaluating the RCUs bound in this scenario. Our numerical experiments verify the accuracy of the proposed approximation. Moreover, when the delays are modeled as fully dependent across fading blocks, numerical results indicate that the number of pilot symbols needed to estimate the fading channel gains to the level of accuracy required in ultra-reliable low-latency communication is also sufficient to acquire sufficiently good synchronization. However, when the delays are modeled as independent across blocks, synchronization becomes the bottleneck for the system performance.
- A. O. Kislal, M. Rajiv, G. Durisi, E. G. Ström, and U. Mitra, “Pilot-assisted URLLC links: Impact of synchronization error,” will be presented at IEEE Int. Conf. Commun. (ICC), Jun. 2024.
- G. Kolovou, S. Oteafy, and P. Chatzimisios, “A remote surgery use case for the IEEE p1918.1 tactile internet standard,” in Proc. IEEE Int. Conf. Commun. (ICC), Montreal, QC, Canada, Aug. 2021, pp. 1–6.
- E.-C. Liou and S.-C. Cheng, “A QoS benchmark system for telemedicine communication over 5G uRLLC and mMTC scenarios,” in Proc. IEEE 2nd Eurasia Conf. Biomed. Eng., Healthcare, Sustainability (ECBIOS), Tainan, Taiwan, Sep. 2020, pp. 24–26.
- Q. Peng, H. Ren, C. Pan, N. Liu, and M. Elkashlan, “Resource allocation for uplink cell-free massive MIMO enabled URLLC in a smart factory,” IEEE Trans. Commun., vol. 71, no. 1, pp. 553–568, Nov. 2023.
- “Study on physical layer enhancements for NR ultra-reliable and low latency case (URLLC) (release 16),” 3GPP, Tech. Rep., Mar. 2019. [Online]. Available: https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3498
- H. Tataria, M. Shafi, A. F. Molisch, M. Dohler, H. Sjöland, and F. Tufvesson, “6G wireless systems: Vision, requirements, challenges, insights, and opportunities,” Proc. IEEE, vol. 109, no. 7, pp. 1166–1199, Mar. 2021.
- C. Yue, V. Miloslavskaya, M. Shirvanimoghaddam, B. Vucetic, and Y. Li, “Efficient decoders for short block length codes in 6G URLLC,” IEEE Commun. Mag., vol. 61, no. 4, pp. 84–90, 2023.
- M. C. Coşkun, G. Durisi, T. Jerkovits, G. Liva, W. Ryan, B. Stein, and F. Steiner, “Efficient error-correcting codes in the short blocklength regime,” Physical Communication, vol. 34, pp. 66–79, 2019.
- G. Durisi, T. Koch, and P. Popovski, “Towards massive, ultra-reliable, and low-latency wireless communication with short packets,” Proc. IEEE, vol. 104, no. 9, pp. 1711–1726, Sep. 2016.
- Y. Polyanskiy, H. V. Poor, and S. Verdú, “Channel coding rate in the finite blocklength regime,” IEEE Trans. Inf. Theory, vol. 56, no. 5, pp. 2307–2359, May 2010.
- A. Anand and G. de Veciana, “Resource allocation and HARQ optimization for URLLC traffic in 5G wireless networks,” IEEE J. Sel. Areas Commun., vol. 36, no. 11, pp. 2411–2421, Oct. 2018.
- W. R. Ghanem, V. Jamali, M. Schellmann, H. Cao, J. Eichinger, and R. Schober, “Codebook based two-time scale resource allocation design for IRS-assisted eMBB-URLLC systems,” in IEEE Globecom Workshops (GC Wkshps), Rio de Janeiro, Brazil, Dec. 2022, pp. 419–425.
- M. Darabi, V. Jamali, L. Lampe, and R. Schober, “Hybrid puncturing and superposition scheme for joint scheduling of URLLC and eMBB traffic,” IEEE Commun. Lett., vol. 26, no. 5, pp. 1081–1085, Feb. 2022.
- Q. Chen, J. Wu, J. Wang, and H. Jiang, “Coexistence of URLLC and eMBB services in MIMO-NOMA systems,” IEEE Trans. Veh. Technol., vol. 72, no. 1, pp. 839–851, Sep. 2023.
- A. Martinez and A. Guillén i Fàbregas, “Saddlepoint approximation of random-coding bounds,” in Proc. Inf. Theory Appl. Workshop, San Diego, CA, USA, Feb. 2011, pp. 257–262.
- J. Östman, G. Durisi, E. G. Ström, M. C. Coşkun, and G. Liva, “Short packets over block-memoryless fading channels: Pilot-assisted or noncoherent transmission?” IEEE Trans. Commun., vol. 67, no. 2, pp. 1521–1536, Feb. 2019.
- A. Lapidoth and S. Shamai (Shitz), “Fading channels: how perfect need ”perfect side information” be?” IEEE Trans. Inf. Theory, vol. 48, no. 5, pp. 1118–1134, May 2002.
- A. O. Kislal, A. Lancho, G. Durisi, and E. G. Ström, “Efficient evaluation of the error probability for pilot-assisted URLLC with massive MIMO,” IEEE J. Sel. Areas Commun., vol. 41, no. 7, pp. 1969–1981, May 2023.
- A. Lancho, J. Östman, G. Durisi, T. Koch, and G. Vazquez-Vilar, “Saddlepoint approximations for short-packet wireless communications,” IEEE Trans. Wireless Commun., vol. 19, no. 7, pp. 4831–4846, Jul. 2020.
- G. C. Ferrante, J. Ostman, G. Durisi, and K. Kittichokechai, “Pilot-assisted short-packet transmission over multiantenna fading channels: A 5G case study,” in Proc. Conf. on Inf. Sci. and Sys. (CISS), Princeton, NJ, U.S.A., Mar. 2018, pp. 1–6.
- J. Östman, A. Lancho, G. Durisi, and L. Sanguinetti, “URLLC with massive MIMO: Analysis and design at finite blocklength,” IEEE Trans. Wireless Commun., vol. 20, no. 10, pp. 6387–6401, Oct. 2021.
- Y. Polyanskiy, “Asynchronous communication: Exact synchronization, universality, and dispersion,” IEEE Trans. Inf. Theory, vol. 59, no. 3, pp. 1256–1270, 2013.
- J. Scarlett, A. Martinez, and A. Guillén i Fàbregas, “Mismatched decoding: Error exponents, second-order rates and saddlepoint approximations,” IEEE Trans. Inf. Theory, vol. 60, no. 5, pp. 2647–2666, May 2014.