Integrated Use of Licensed- and Unlicensed-Band mmWave Radio Technology in 5G and Beyond

Abstract

The 3GPP standardization rapidly moves forward with studies of a wide-bandwidth waveform as well as an adaptation of the emerging 5G new radio (NR)-based access to the unlicensed spectrum (NR-U). One of the basic architectures for NR-U involves carrier aggregation of an anchor-licensed-NR carrier and a secondary carrier in unlicensed spectrum, which altogether allows for seamless traffic offloading in scenarios where multi-gigabit data rates are required. While today's research on NR-U addresses mostly physical-and protocol-layer aspects, a system-level performance of the NR-U offloading mechanisms has not been investigated thoroughly. In this paper, we develop a mathematical queuing-theoretic framework that is mindful of the specifics of millimeter-wave (mmWave) session dynamics and may serve as a flexible tool for the analysis of various strategies for the integrated use of licensed and unlicensed mmWave bands in terms of the session drop probability and system utilization. To illustrate this, we select three distinct strategies (based on sequential service, probabilistic offloading, or proportional splitting), and complement our mathematical models with a detailed performance evaluation in a representative massive augmented/virtual reality scenario. Based on this quantitative analysis of the selected schemes, we conclude that proportional splitting of traffic between the two mmWave bands leads to a better performance. We believe that the contributed mathematical analysis can become an important building block in further system development and service optimization across many usage scenarios.

Resource Management in Future Millimeter Wave Small-Cell Networks: Joint PHY-MAC Layer Design

“…2a. The results 1 show that, by configuring SBS and UE antenna beamwidths the optimum throughput performance can be achieved at the best trade-off between the achievable antenna gain and the beam alignment overhead. In particular, when setting up a wider UE antenna beamwidth, a narrower SBS antenna beamwidth is desired for the optimum throughput.…”

“…The mmWave frequency band due to its large available bandwidth is considered as a key enabler for the fifth generation (5G) network and beyond 5G (B5G) network to provide the much needed new spectrum opportunities to address challenges such as the exponential growth in traffic, massive connectivity of massive number of diverse devices and enhanced data rate requirements [1], [2]. Several characteristics of mmWave communication [3], such as short wavelength, shorter coverage range, sensitivity to blockage, high penetration loss, require highly directional transmissions in order to overcome the propagation defects, and to provide better coverage with enhanced capacity.…”

Efficient Management of Multicast Traffic in Directional mmWave Networks

“…where |A| is the complexity due to the "while" cycle over all |A| users in the worst case of the unicast transmission (lines [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. This means that each beam j covers only a single user.…”

“…Particularly, the 3GPP provides for the use of licensed mmWave sub-bands (e.g., 24.25-27.5, 27.5-29.5, 37-40, 64-71 GHz) for the 5G mmWave cellular networks [3], whereas IEEE actively explores the unlicensed band at 60 GHz for the next-generation wireless local area networks (WLANs) [4]. Bandwidths of cellular systems range between 500 MHz and 2 GHz, which results in a cell capacity of several gigabits per second [5], [6], whereas the IEEE 802.11ay enables Wi-Fi devices to achieve up to 100 Gbps [7]. In this regard, mmWave has been envisaged as a new technology layout for real-time heavy-traffic applications, such as ultra-high definition (UHD) video streaming [8], extended reality (XR) broadcasting [9] that includes augmented, virtual, and mixed reality (AR/VR/MR), and proximate gaming [10].…”

Analysis and Optimization for Robust Millimeter-Wave Communications

“…As shown in Fig. 1.1, some countries have already performed public auctions for allocating part of them [5], whereas the 60 GHz band is planned to be assigned to unlicensed mm-wave communications [6].…”