caa a22 4500 606190104 CHVBK 20210128100853.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s10776-015-0285-9 doi (NATIONALLICENCE)springer-10.1007/s10776-015-0285-9 User Cooperation for 5G Wireless Access Networks [Elektronische Daten] [Amine Maaref, Yu Cao] Device-to-device (D2D) connectivity is one of the main enablers for future fifth generation (5G) radio access networks. In this paper, we introduce a new model for user cooperation in 5G radio access networks termed frequency-selective soft forwarding (SF). SF is based on soft-processing by a target user equipment (TUE) of selectively forwarded soft information data by a set of cooperating user equipments acting as mobile relays towards the TUE. SF exploits the inherent frequency selectivity and broadcast nature of the downlink radio access channel for the sake of enabling efficient user cooperation and seamless integration of D2D connectivity into cellular radio access networks. Several variants of SF are investigated, including centralized and distributed approaches, thus offering various tradeoffs of performance versus signaling overhead cost. We also propose a hybrid cooperation mode selection strategy which leverages the performance benefits of SF and the low-overhead cost of decode-and-forward (DF) relaying to enhance the performance of 5G radio access networks. Exhaustive simulation results using a state-of-the-art long-term evolution-compliant link-level simulator show that the proposed user cooperation strategies well outperform baseline cooperation schemes relying on conventional DF and approach the performance of optimal joint reception with significantly lower cost in terms of D2D resource utilization and signaling overhead. Springer Science+Business Media New York, 2015 5G wireless access networks nationallicence LTE-advanced (LTE-A) nationallicence User cooperation nationallicence Frequency-selective soft forwarding (SF) nationallicence Log-likelihood ratio (LLR) nationallicence Device-to-device (D2D) communications nationallicence Maaref Amine Canada Research Center (CRC), Huawei Technologies Canada Co., Ltd., 303 Terry Fox Dr., 4th Floor, K2K 3J1, Ottawa, ON, Canada aut Cao Yu Canada Research Center (CRC), Huawei Technologies Canada Co., Ltd., 303 Terry Fox Dr., 4th Floor, K2K 3J1, Ottawa, ON, Canada aut International Journal of Wireless Information Networks Springer US; http://www.springer-ny.com 22/4(2015-12-01), 298-311 1068-9605 22:4<298 2015 22 10776 https://doi.org/10.1007/s10776-015-0285-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10776-015-0285-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Maaref Amine Canada Research Center (CRC), Huawei Technologies Canada Co., Ltd., 303 Terry Fox Dr., 4th Floor, K2K 3J1, Ottawa, ON, Canada aut NATIONALLICENCE 700 1- Cao Yu Canada Research Center (CRC), Huawei Technologies Canada Co., Ltd., 303 Terry Fox Dr., 4th Floor, K2K 3J1, Ottawa, ON, Canada aut NATIONALLICENCE 773 0- International Journal of Wireless Information Networks Springer US; http://www.springer-ny.com 22/4(2015-12-01), 298-311 1068-9605 22:4<298 2015 22 10776