TY - JOUR KW - Interference KW - Communication system security KW - Wireless communication KW - Antenna arrays KW - Physical layer KW - Network security KW - Wireless sensor networks KW - 5G mobile communication KW - Heterogeneous networks KW - Ultra-dense networks PB - IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC N2 - Heterogeneous ultra-dense networks enable ultra-high data rates and ultra-low latency through the use of dense sub-6 GHz and millimeter-wave small cells with different antenna configurations. Existing work has widely studied spectral and energy efficiency in such networks and shown that high spectral and energy efficiency can be achieved. This article investigates the benefits of heterogeneous ultra-dense network architecture from the perspectives of three promising technologies, physical layer security, caching, and wireless energy harvesting, and provides an enthusiastic outlook toward application of these technologies in heterogeneous ultra-dense networks. Based on the rationale of each technology, opportunities and challenges are identified to advance the research in this emerging network. ID - discovery10055174 AV - public Y1 - 2018/06// EP - 55 TI - A New Look at Physical Layer Security, Caching, and Wireless Energy Harvesting for Heterogeneous Ultra-Dense Networks A1 - Wang, L A1 - Wong, K-K A1 - Jin, S A1 - Zheng, G A1 - Heath, RW JF - IEEE Communications Magazine UR - https://doi.org/10.1109/MCOM.2018.1700439 SN - 0163-6804 IS - 6 N1 - This version is the author accepted manuscript. For information on re-use, please refer to the publisher?s terms and conditions. SP - 49 VL - 56 ER -