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  • Print publication year: 2017
  • Online publication date: April 2017

20 - LTE-Unlicensed: Overview and Distributed Coexistence Design

from Part III - Network Protocols, Algorithms, and Design
Summary

With more users, more mobile phones and tablets, more connections to homes and offices, and richer content sharing over wireless communication networks, the industry is facing an exponential increase in mobile broadband traffic in the frequency spectrum from 700 MHz to 2.6 GHz. To meet this demanding challenge, an intuitive idea is to add more licensed spectrum, which would ensure predictable performance in terms of mobility. However, for various reasons, it is possible that sufficient additional licensed spectrum will not be available in the near future. On the other hand, the amount of unlicensed spectrum already assigned or planned to be assigned is comparable or even more than the licensed spectrum. By taking full advantage of the unlicensed spectrum, the burden on the licensed spectrum can be relieved. Unlicensed spectrum has already been utilized in multiple technologies, such as Wi-Fi and Bluetooth, and now there is a new member of the unlicensed family at 5 GHz for mobile broadband. By extending the benefits of Long Term Evolution-Advanced (LTE-A) to the unlicensed spectrum, we can boost the capacity, while maintaining seamless mobility and predictable performance.

Although it has great potential, LTE-Unlicensed is still in its infancy and faces some major challenges. Only by careful design can the LTE-Unlicensed technique truly benefit us with tremendous advantages. Thus, in this chapter, we give a comprehensive introduction to the benefits and design principles of LTE-Unlicensed. In addition, two specific implementation cases are provided for illustration purposes. This chapter is organized as follows. In Section 20.1, the motivation for proposing the LTE-Unlicensed technique will be stated. Then the design challenges in and potential solutions for LTE-Unlicensed will be discussed in Section 20.2. Two distributed resource allocation applications utilizing matching-based approaches will be introduced in Section 20.3. Finally, conclusions are drawn in Section 20.4.

Motivations

Currently, technologies such as IEEE 802.11 (Wi-Fi), 802.15.1 (Bluetooth), and 802.15.4 (ZigBee) are implemented in the 2.4 GHz ISM (Industry, Scientific, and Medical) and 5 GHz U-NII (Unlicensed National Information Infrastructure) bands, more commonly referred to as the unlicensed bands. Some operators have deployed a large number of Wi-Fi access points (APs) to offload cellular traffic to the unlicensed spectrum. Wi-Fi offloading strikes a trade-off between capacity and performance.

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Key Technologies for 5G Wireless Systems
  • Online ISBN: 9781316771655
  • Book DOI: https://doi.org/10.1017/9781316771655
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[1] Huawei, “U-LTE: Unlicensed spectrum utilization of LTE,” White Paper, Sep. 2014.
[2] Qualcomm, “Making the best use of unlicensed spectrum for 1000x,” White Paper, 2014.
[3] 3GPP, “LTE in unlicensed spectrum,” Jun. 2014. Available at www.3gpp.org/news-events/ 3gpp-news/1603-lte-in-unlicensed.
[4] Qualcomm, “LTE Wi-Fi link aggregation,” Mar. 2015. Available at www.qualcomm.com/ videos/lte-wi-fi-link-aggregation.
[5] Verizon, “LTE-U Forum.” Available at www.lteuforum.org/.
[6] Qualcomm, “Introducing MuLTEfire: LTE-like performance with Wi-Fi-like simplicity,” Jun. 2015. Available at www.qualcomm.com/news/onq/2015/06/11/introducing-multefire -lte-performance-wi-fi-simplicity.
[7] LTE-U Forum, “LTE-U SDL Coexistence Specifications,” Jun. 2015.
[8] Alcatel-Lucent, Ericsson, Qualcomm Technologies Inc., Samsung Electronics, and Verizon, “LTE-U technical report: coexistence study for LTE-U SDL v1.0,” Tech. Rep., Feb. 2015.
[9] T., Nihtila, V., Tykhomyrov, O., Alanen, M. A., Uusitalo, A., Sorri, M., Moisio, S., Iraji, R., Ratasuk, and N., Mangalvedhe, “System performance of LTE and IEEE 802.11 Coexisting on a shared frequency band,” in Proc. of IEEE Wireless Communications and Networking Conf. (WCNC), Apr. 2013.
[10] A. M., Cavalcante, E., Almeida, R. D., Vieira, F., Chaves, R., Paiva, F., Abinader, S., Choudhury, E., Tuomaala, and K., Doppler, “Performance evaluation of LTE and Wi-Fi coexistence in unlicensed bands,” in Proc. of IEEE Vehicular Technology Conf. (VTC), Jun. 2013.
[11] R., Zhang, M., Wang, L. X., Cai, Z., Zheng, X., Shen, and L. L., Xie, “LTE-Unlicensed: The future of spectrum aggregation for cellular networks,” IEEE Wireless Commun., vol. 22, no. 3, pp. 150–159, Jun. 2015.
[12] Qualcomm, “Qualcomm research LTE in unlicensed spectrum: Harmonious coexistence with Wi-Fi,” White Paper, Jun. 2014.
[13] F. S., Chaves, E. P. L., Almeida, R. D., Vieira, A. M., Cavalcante, F. M., Abinader, S., Choudhury, and K., Doppler, “LTE UL power control for the improvement of LTE/Wi-Fi coexistence,” in Proc. of IEEE Vehicular Technology Conf. (VTC), Sep. 2013.
[14] E., Almeida, A. M., Cavalcante, R. C. D., Paiva, F. S., Chaves, F. M., Abinader, R. D., Vieira, S., Choudhury, E., Tuomaala, and K., Doppler, “Enabling LTE/WiFi coexistence by LTE blank subframe allocation,” in Proc. of IEEE International Conf. on Communications (ICC), Jun. 2013.
[15] H., Zhang, Y., Xiao, L. X., Cai, D., Niyato, L., Song, and Z., Han, “A hierarchical game approach for multi-operator spectrum sharing in LTE unlicensed,” in Proc. of IEEE Global Communications Conf. (GLOBECOM), Dec. 2015.
[16] Y., Gu, W., Saad, M., Bennis, M., Debbah, and Z., Han, “Matching theory for future wireless networks: Fundamentals and applications,” IEEE Commun. Mag., vol. 53, no. 5, pp. 52–59, May 2015.
[17] Y., Gu, Y., Zhang, M., Pan, and Z., Han, “Matching and cheating in device to device communications underlying cellular networks,” IEEE J. Sel. Areas Commun., vol. 33, no. 10, pp. 2156–2166, Oct. 2015.
[18] S., Bayat, R. H. Y., Louie, Z., Han, Y., Li, and B., Vucetic, “Distributed stable matching algorithm for physical layer security with multiple source-destination pairs and jammer nodes,” in Proc. of IEEE Wireless Communications and Networking Conf. (WCNC), Apr. 2012.
[19] Y., Gu, Y., Zhang, M., Pan, and Z., Han, “Student admission matching based content-cache allocation,” in Proc. of IEEE Wireless Communications and Networking Conf. (WCNC), Mar. 2015.
[20] W., Saad, Z., Han, R., Zheng, M., Debbah, and H. V., Poor, “A college admissions game for uplink user association in wireless small cell networks,” in Proc. of IEEE INFOCOM, Apr. 2014.
[21] D., Gale and L. S., Shapley, “College admissions and the stability of marriage,” Am. Math. Monthly, vol. 69, no. 1, pp. 9–15, Jan. 1962.
[22] Y., Gu, Y., Zhang, L. X., Cai, M., Pan, L., Song, and Z., Han, “Exploiting student–project allocation matching for spectrum sharing in LTE-unlicensed,” in Proc. of IEEE Global Communications Conf. (GLOBECOM), Dec. 2015.
[23] D. F., Manlove, Algorithmics of Matching under Preferences, World Scientific, 2013.
[24] A. H. A., El-Atta and M. I., Moussa, “Student project allocation with preference lists over (student, project) pairs,” in Proc. of International. Conf. on Computer and Electrical Engineering (ICCEE), Dec. 2009.
[25] A., Roth and M. A. O., Sotomayor, Two-sided Matching: A Study in Game-Theoretic Modeling and Analysis, Cambridge University Press, 1992.
[26] A., Goldsmith, Wireless Communications, Cambridge University Press, 2004.
[27] F., Pantisano, M., Bennis,W. Saad, S., Valentin, and M., Debbah, “Matching with externalities for context-aware user–cell association in small cell networks,” in Proc. of IEEE Global Communications Conf. (GLOBECOM), Dec. 2013.
[28] F., Kojima and M. U., Ünver, “Random paths to pairwise stability in many-to-many matching problems: A study on market equilibration,” Int. J. Game Theory, vol. 36, no. 3, pp. 473–488, 2006.