Abstract
This paper considers the hidden-node problem in downlink transmission of an LTE-U and WiFi coexistence system operating in unlicensed bands. An enhanced LTE-U node structure is first presented, in which a WiFi module is introduced in an LTE-U eNB, and the RRC and MAC functional blocks in both LTE-U eNB and LTE-U UE are redefined. The purpose is to enable information exchange between an LTE-U node and a WiFi node in order to handle the hidden-node problem. Based on the enhanced LTE-U node structure, an enhanced listen-before-talk (e-LBT) mechanism is further presented, which incorporates an RTS/CTS handshaking procedure in the basic LBT mechanism. To support RTS/CTS handshaking, the relevant information that needs to be exchanged between e-MACWiFi in the WiFi module and e-RRC in the LTE-U module of an LTE-U node is identified, and the message format to be exchanged between e-MACWiFi and e-RRC is defined. Simulation results show that the proposed e-LBT mechanism can significantly improve the performance of the coexistence system in terms of the LTE-U system throughput and WiFi system throughput as compared with the basic LBT mechanism.










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References
Huawei (2013) Discussion paper on unlicensed Spectrum integration to IMT systems. 3GPP ran 62 RP-131723
3GPP TR 36.889 (2015) Study on Licensed-Assisted Access to Unlicensed Spectrum (Release 13)
Nihtila T et al. (2013) System performance of LTE and IEEE 802.11 Coexisting on a Shared Frequency Band. In: Proceedings of IEEE Wireless Communications and Networking Conference, WCNC’13
Almeida E et al. (2013) Enabling LTE/WiFi coexistence by LTE blank subframe allocation. In: proceedings of IEEE international conference on communications, ICC’13
Qualcomm (2014) LTE in unlicensed spectrum: harmonious coexistence with WiFi
IEEE Std 802.11 (2012) Wireless LAN Medium access Control (MAC) and Physical Layer (PHY) specification
Panasonic (2015) Hidden and Exposed Station statistics and implications in LAA scenarios. 3GPP TSG-ran R1–151018
Samsung (2015) Discussion on hidden node issue for LAA. 3GPP TSG-ran R1–151047
Lee H, Kim H, Yang HJ, Kim JT, Baek SK (2018) Performance analysis of license assisted access LTE with asymmetric hidden terminals. IEEE Trans Mob Comp. https://doi.org/10.1109/TMC.2018.2793230
Zhang T, Zhao J, Chen Y (2017) Hidden Node Aware Resource Allocation in Licensed-Assisted Access Systems. In: Proceedings of IEEE Global Communications Conference, Globecom’17
Lien SY, Cheng SM, Chen KC, Kim DI (2016) Resource-optimal licensed-assisted-access in heterogeneous cloud radio access networks with heterogeneous carrier communications. IEEE TransVeh Tech 65(12):9915–9930
Cui Q et al (2014) A unified protocol stack solution for LTE and WLAN in future mobile converged networks. IEEE Wirel Commun 21(6):24–33
Song H, Fang X, Yan L, Fang Y (2017) Control/user plane decoupled architecture utilizing unlicensed bands in LTE systems. IEEE Wireless Commun 24(5):132–142
Ling J, Perez DL, Khawer MR (2017) Practical LTE and WiFi coexistence techniques beyond LBT. IEEE Commun Mag 55(10):127–133
Yi SJ, Chun SD, Lee YD, Park SJ, Jung SH (2012) Radio Protocols for LTE and LTE-Advanced. ISBN: 9781118188538. Wiley, New Jersey
Song H, Fang X (2015) A Spectrum Etiquette Protocol and Interference Coordination for LTE in Unlicensed Bands (LTE-U). In: Proceedings of IEEE International Conference on Communication Workshop, ICCW’13
Giupponi L, Henderson T, Bojovic B, Miozzo M (2016) Simulating LTE and Wi-Fi Coexistence in Unlicensed Spectrum with NS-3 arXiv: 1604.06826
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This work was supported by the National Natural Science Foundation of China under Grant No. 61771131 and No. 61521061.
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Zheng, J., Chu, L. & Xiao, J. e-LBT: an Enhanced Listen Before Talk Mechanism for Collision Avoidance in an LTE-U and WiFi Coexistence System. Mobile Netw Appl 23, 1396–1405 (2018). https://doi.org/10.1007/s11036-018-1081-4
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DOI: https://doi.org/10.1007/s11036-018-1081-4