An expansion of services and unprecedented traffic growth is anticipated in future networks, aligned with the adoption of the long-awaited Fifth Generation (5G) of mobile communications To support this demand, without exposing mobile operators to the pressure of CAPEX and OPEX, 5G uses new frequency bands, and adopts promising trends, including: densification, softwarization, and autonomous management While the first technology is proposed to handle the traffic growth requirements, the softwarization and autonomous management are expected to play, in synergy, to ensure the desired trade-off between reducing the CAPEX and OPEX, while guaranteeing the quality of service (QoS) Softwarization is expected to transform the network design, from one size fits all, to more demand oriented adaptive resource allocation In this work, we focus on this point, by discussing how these technologies act in synergy towards enabling RAN sharing Particularly, we focus on how they fit into the issue of energy efficient Multi-Operator Resource Allocation (MO-RA) After a survey and classification of schemes leveraging this synergy for distinct resource allocation (RA) objectives, we present a detailed survey and qualitative classification of RA schemes with respect to energy efficiency This work presents an innovative survey, since it concentrates on multiple operators, and the enabling of Mobile Virtual Network Operators (MVNOs), which will come into play with the complete virtualization of mobile networks Based on the deep literature analysis of the different operations that can bring energy savings to MO-RA, we conclude the work with listing open challenges and future research directions

On Energy Efficient Resource Allocation in Shared RANs: Survey and Qualitative Analysis

Proactive Handover Based on Human Blockage Prediction Using RGB-D Cameras for mmWave Communications

This paper proposes a proactive base station selection system for millimeter-wave (mmWave) communications based on human blockage prediction using RGB and depth (RGB-D) cameras. In mmWave communications, the frame loss rate increases and the throughput sharply decreases if a pedestrian blocks a line-of-sight (LOS) path between a station and a base station.To address this human blockage problem, multiple base stations can be arranged so as to maintain at least one LOS path.For base station selection in particular, RGB-D camera images can be used to estimate the mobility of pedestrians and to predict when blockage of LOS paths will occur. Using IEEE 802.11ad-based wireless local area network (WLAN) devices, a testbed for implementing the proposed system was built. The results of experiments on the influence of human blockage confirmed the presence of significant throughput degradation due to human blockage.Furthermore, the innovative experimental results demonstrated that the proactive base station selection system can considerably reduce the duration of human blockage-induced degradation of throughput performance relative to reactive base station selection systems based on throughput performance.

Proactive Base Station Selection Based on Human Blockage Prediction Using RGB-D Cameras for mmWave Communications

Mobility may degrade the performance of next-generation vehicular networks operating at the millimeter-wave spectrum: frequent mis-alignment and blockages require repeated beam training and handover, and incur enormous overhead. Nevertheless, mobility induces temporal correlations in the communication beams and in blockage events. In this paper, an adaptive design of beam training, data transmission and handover is proposed, that learns and exploits these temporal correlations to reduce the beam training overhead and optimally trade-off throughput and power consumption. At each time-slot, the serving base station (BS) decides to perform either beam training, data communication, or handover when blockage is detected, under uncertainty in the system state. The decision problem is cast as a partially observable Markov decision process, and the goal is to maximize the throughput delivered to the UE, under an average power constraint. To address the high dimensional optimization, an approximate constrained point-based value iteration (C-PBVI) method is developed, which simultaneously optimizes the primal and dual functions to meet the power constraint. Numerical results demonstrate a good match between the analysis and a simulation based on 2D mobility and 3D analog beamforming via uniform planar arrays at both BSs and UE, and reveal that C-PBVI performs near-optimally, and outperforms a baseline scheme with periodic beam training by 38% in spectral efficiency. Motivated by the structure of the C-PBVI policy, two heuristics are proposed, that trade complexity with sub-optimality, and achieve only 4% and 15% loss in spectral efficiency.

/pdf/mobility-and-blockage-aware-communications-in-millimeter-jpvqnc8dcm.pdf

Mobility and Blockage-aware Communications in Millimeter-Wave Vehicular Networks

Finding the optimal transmit and receive beam pair for reliable communication can be challenging, especially in highly dynamic environments Side-information from on-board sensors at the user equipment (UE) can be used to aid the beam management (BM) process In this work, we use the orientation information coming from inertial measurement unit (IMU) for effective BM Specifically, we use particle filter (PF) to fuse the reference signal received power (RSRP) information with orientation information We perform extensive simulations using realistic ray-tracing channels, practical beam patterns, and various UE movement and rotation speeds Simulation results show the proposed strategy can greatly improve the beam prediction accuracy and reduce the power loss caused by sub-optimal beam-selection

/pdf/orientation-assisted-beam-management-for-beyond-5g-systems-2ttmz3s1i4.pdf

Orientation-Assisted Beam Management for Beyond 5G Systems

In a millimeter wave (mmWave) communication system with transmit/receive (Tx/Rx) beamforming antennas, small variation in device behavior or an environmental change can destroy beam alignment, resulting in power loss in the received signal. In this situation, the beam-tracking technique purely based on the received signal is not effective because both behavioral changes (rotation, displacement) and environmental changes (blockage) result in power loss in the received signal. In this paper, a motion sensor based on microelectromechanical systems (MEMS) as well as an electrical signal is used for beam tracking to identify the cause of beam error, and an efficient beam-tracking technique is proposed. The motion sensors such as accelerometers, gyroscopes, and geo-magnetic sensor are composed of an attitude heading reference system (AHRS) and a zero-velocity detector (ZVD). The AHRS estimates the rotation angle and the ZVD detects whether the device moves. The proposed technique tracks a beam by handling the specific situation depending on the cause of beam error, minimizing the tracking overhead. The performance of the proposed beam-tracking technique is evaluated by simulations in three typical scenarios.

/pdf/application-of-motion-sensors-for-beam-tracking-of-mobile-16w72y4fb9.pdf

Application of motion sensors for beam-tracking of mobile stations in mmWave communication systems

The random-access (RA) technique is a key procedure in cellular networks and self-organizing networks (SONs), but the overall processing time of this technique in millimeter-wave (mm-wave) cellular systems with directional beams is very long because RA preambles (RAPs) should be transmitted in all directions of Tx and Rx beams. In this paper, two different types of preambles (RAP-1 and RAP-2) are proposed to reduce the processing time in the RA stage. After analyzing the correlation property, false-alarm probability, and detection probability of the proposed RAPs, we perform simulations to show that the RAP-2 is suitable for RA in mm-wave cellular systems with directional beams because of the smaller processing time and high detection probability in multiuser environments.

/pdf/random-access-technique-for-self-organization-of-5g-3seklozxwp.pdf

Random-Access Technique for Self-Organization of 5G Millimeter-Wave Cellular Communications

The random access (RA) technique is a key procedure in cellular networks but the overall duration of this technique in millimeter-wave (mm-wave) cellular systems with directional beams is very long because RA preambles (RAPs) should be transmitted in all directions of Tx and Rx beams. In this paper, two different types of preambles (RAP-1 and RAP-2) are proposed to reduce the processing time in the RA stage. In simulation, it is shown that the RAP-2 is suitable for RA in mm-wave cellular systems with directional beams because of the smaller processing time and high detection probability in multi-user environments.

Joo Pyo Han

Papers

Application of motion sensors for beam-tracking of mobile stations in mmWave communication systems

Random-Access Technique for Self-Organization of 5G Millimeter-Wave Cellular Communications

Random access technique for millimeter-wave cellular communications