NeTS: Small: Coordinated Beam Discovery, Association, and Handover in Ultra-Dense Millimeter Wave Cellular Networks

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Ever increasing demands for higher mobile data rates have resulted in exploration of new wireless technologies such as millimeter wave (mmWave) cellular networks due to large bandwidth availability at mmWave frequencies. However, higher channel propagation loss and higher probability of signal blockage in the mmWave band, as compared to the microwave band, have introduced challenges in establishing and maintaining the link between base stations and user equipment. In order to compensate for the losses, these devices use a large number of antennas and narrow beams to achieve high beamforming gains needed to establish the link. Further, ultra-dense base station deployment is needed to provide better coverage in the region. As a result, the mmWave cellular networks face new design challenges: i) establishing the link during initial channel access, ii) coordinated association of a user equipment to base stations and allocation of base station resources (beams and time) to users, and iii) beam adaptation for mobile user equipment and managing handovers in ultra-dense mobile networks. The proposed technologies are of fundamental importance to realize future ultra-dense 5G cellular networks, support user mobility and enable various applications requiring high data rate including video streaming, cloud computing, virtual reality, and augmented reality. This project will address these challenges and enable ultra-fast, low delay, and high throughput cellular networks in the mmWave band. First, it aims to develop an initial access procedure needed to establish the link between base stations and user equipment using compressive sensing measurements while considering practical hardware impairments. Next, it proposes to use the channel parameters obtained during the initial access to associate users with a specific base station and allocate resources accordingly. The novel association techniques will allow multiple base stations to simultaneously serve one user using independent RF chains, thereby increasing the data rate and reducing the probability of outage. Finally, a novel mobility management technique based on low-complexity beam-tracking and handover algorithms is proposed to enable seamless data transfer in ultra-dense mobile network. The proposed methodology will involve formulation of optimization framework for problems of coordinated beam association, resource allocation, and handovers and design of low complexity algorithms that solve the underlying optimization while enabling their practical realization.