Wi-Fi and LTE-LAA Coexistence Problems, Challenges and Features in 5GHz Unlicensed Bandwidth

The demand for high data rate and stable quality of service from cellular networks’ subscribers is a huge challenge for cellular operators. To overcome this issue, while keeping high data rate and stable quality of service more bandwidth is required. The lack of licensed bandwidth and also its high cost make it hard for operators to overcome this issue. To find an effective solution and expand the capacity of cellular networks, operators have started deployment of Long Term Evolution (LTE) in unlicensed bandwidth, exactly utilizing 5GHz unlicensed bandwidth in small cell scenarios. The extension of LTE to the 5GHz unlicensed bandwidth where it is already in used by Wi-Fi will create huge coexistence problems between Wi-Fi and LTE. It results due to different channel access mechanisms of Wi-Fi and LTE. This paper presents the channel access mechanisms of Wi-Fi and LTE-Licensed Assisted Access (LTE-LAA), coexistence problems, challenges, privileges, coexistence features of LTE and Wi-Fi. Finally, simulations are provided for LTE-LAA based Listen Before Talk (LBT) mechanism and Wi-Fi to show that LTE-LAA with LBT mechanism is friendly to the Wi-Fi networks when using the same 5GHz unlicensed channel. The simulation results illustrate that LTE-LAA based-LBT channel access mechanism by alone cannot bring a fair coexistence between these two technologies, and it needs further improvement.

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[1] N. R. a. I. Guvenc, "Licensed-Assisted Access for WiFi-LTE Coexistence in the Unlicensed Spectrum," in IEEE Globecom Workshops (GC Wkshps), Austin, TX, USA, 2014.

[2] J. A.-F. B. H. Alireza Babaei, "On the Impact of LTE-U on Wi-Fi Performance," in IEEE 25th IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communication (PIMRC), Washington, DC, USA, 2014.

[3] Qualcomm, "Progress on LAA and its relationship to LTE-U and MulteFire," Qualcomm Technologies, 2016.

[4] R. v. Steve, Wireless Networking Technology, UK: Newnes, 2007.

[5] S. K. F. H. John D. Matyjas, Spectrum Sharing in Wireless Networks, Florida: CRC Press, 2016.

[6] Devid, Certified Wireless Network Administrator, Indiana: Sybex, 2014.

[7] K. a. H. Matyjas, Spectrum Sharing in Wireless Networks, Florida: CRC Press, 2016.

[8] Qualcomm, "Progress on LAA and its relationship to LTE-U and MulteFire," Qualcomm, 2016.

[9] 3GPP, "Status report for WI: LicensedAssisted Access to Unlicensed Spectrum," 3GPP, Spain , 2016.

[10] L. N. e. al, "Unified access in licensed and unlicensed bands in LTE-A Pro and 5G," Samsung, Texas, 2017.

[11] h. s. a. p. a. j. c. z. boon loong ng, "Unified access in licensed and unlicensed bands in LTE-A Pro and 5G," 12 Jul 2017. [Online]. Available: https://www.cambridge.org/core/journals/apsip a-transactions-on-signal-and-informationprocessing/article/unified-access-in-licensedand-unlicensed-bands-in-ltea-pro-and5g/3D374A7EDC19D4D84E9EBF20362FC7 B8/core-reader#. [Accessed 09 Jul 2019].

[12] A. C. C. V. P. S. C. T. D. Abinader, "Enabling the Coexistence of LTE and Wi-Fi in Unlicensed Bands," IEEE Communications Magazine, vol. 52, no. 11, pp. 54-61, 2014.

[13] I. Poole, "Wi-Fi / WLAN Channels, Frequencies, Bands & Bandwidths," Radioelectronic, 21 Nov 2016. [Online]. Available: https://www.radioelectronics.com/info/wireless/wi-fi/80211- channels-number-frequencies-bandwidth.php. [Accessed 23 Aug 2019].

[14] G. A. a. M. BOJOVIC´, "Evaluating Unlicensed LTE Technologies: LAA vs LTEU," IEEE Access , vol. 7, pp. 89714 - 89751, 2019.

[15] C. W. a. A. Mahanti, "Ambient Interference Effects inWi-Fi Networks," in 9th International IFIP TC 6 Networking Conference (NETWORKING), Chennai, 2010.

[16] K. T. L. F. Sadek, "Extending LTE to Unlicensed Band – Merit and Coexistence," in IEEE International Conference on Communication Workshop (ICCW), London, UK, 2015.

[17] J. a. Wannstrom, "Carrier Aggregation explained," 3GPP, 16 June 2013. [Online]. Available: http://www.3gpp.org/technologies/keywordsacronyms/101-carrier-aggregation-explained. [Accessed 24 10 2018].

[18] P. a. Ian, "LTE CA: Carrier Aggregation Tutorial," Radio-electronics, 18 11 2017. [Online]. Available: https://www.radioelectronics.com/info/cellulartelecomms/ltelong-term-evolution/4g-lte-advanced-carrierchannel-aggregation.php. [Accessed 23 10 2018].

[19] C. Cox, An Introduction to LTE, UK: WILEY, 2014.

[20] L. a. pedrini, "What is Retransmission, ARQ and HARQ?," telecomehall, 22 June 2012. [Online]. Available: http://www.telecomhall.com/what-isretransmission-arq-and-harq.aspx. [Accessed 15 9 2018].

[21] P. a. Monica, "LTE unlicensed and Wi-Fi: moving beyond coexistence," Senza Fili, London, 2015.

[22] B. a. Jay, "The LTE-U Vs. WiFi Debate," Network computing, 05 Dec 2016. [Online]. Available: https://www.networkcomputing.com/wirelessinfrastructure/lte-u-vs- wifidebate/1619382711. [Accessed 01 Nov 2018].

[23] A. V. D. Cavalcante, "Performance Evaluation of LTE and Wi-Fi Coexistence in Unlicensed Bands," in IEEE 77th Vehicular Technology Conference (VTC Spring), Dresden, Germany, 2013.

[24] LTE-Forum, "Coexistence Study for LTE-U SDL V1.0 (2015 -02)," LTE-Forum, Stockholm, 2015.

[25] S. K. ,. Jian, "Coexistence of Wi-Fi and LAALTE: Experimental evaluation, analysis and insights," in IEEE International Conference on Communication Workshop (ICCW), London, UK, 2015.

[26] ns3, "Simulator," ns3, [Online]. Available: https://www.nsnam.org/.

[27] 3GPP, "3GPP TR 36.889, Study on LicensedAssisted Access to Unlicensed Spectrum," 3GPP, 2015.

[28] S. P. J. S. Erik Dahlman, 4G, LTE-Advanced Pro and the Road to 5G, London: Elsevier, 2016.

[29] B. A.-F. Padden, "Overview of EU LBT and its Effectiveness for Coexistence of LAA LTE and Wi-Fi," 04 11 2014. [Online]. Available: https://vdocuments.site/download/submissiondoc-ieee-80219-140082r0-november-2014- alireza-babaei-cablelabsslide. [Accessed 13 08 2018].