Fast Cell Discovery in mm-Wave 5G Networks with Context Information

Abstract

The exploitation of mm-wave bands is one of the key-enabler for 5G mobile radio networks. However, the introduction of mm-wave technologies in cellular networks is not straightforward due to harsh propagation conditions that limit the mm-wave access availability. Mm-wave technologies require high-gain antenna systems to compensate for high path loss and limited power. As a consequence, directional transmissions must be used for cell discovery and synchronization processes: this can lead to a non-negligible access delay caused by the exploration of the cell area with multiple transmissions along different directions. The integration of mm-wave technologies and conventional wireless access networks with the objective of speeding up the cell search process requires new 5G network architectural solutions. Such architectures introduce a functional split between C-plane and U-plane, thereby guaranteeing the availability of a reliable signaling channel through conventional wireless technologies that provides the opportunity to collect useful context information from the network edge. In this article, we leverage the context information related to user positions to improve the directional cell discovery process. We investigate fundamental trade-offs of this process and the effects of the context information accuracy on the overall system performance. We also cope with obstacle obstructions in the cell area and propose an approach based on a geo-located context database where information gathered over time is stored to guide future searches. Analytic models and numerical results are provided to validate proposed strategies.

On the Beamformed Broadcasting for Millimeter Wave Cell Discovery: Performance Analysis and Design Insight

“…• A detailed system-level performance evaluation for mm-wave cell discovery. Different from the linklevel analysis in [10], [18], [24], [27], we derive system-level performance metrics to capture the cell discovery efficiency, including the CDL and the OH. Our analytical results are validated against the detailed system-level simulations.…”

Genetic Algorithm‐Based Beam Refinement for Initial Access in Millimeter Wave Mobile Networks

“…In [14], an accurate analytical framework for MMW system performance has been developed. Impact of obstacles on the cell search process is considered in [15] for the first time, and a geo-located context database is proposed to speed up the cellular attachment operations by storing and processing the information about the previous cell discovery attempts.…”

“…For this reason, codebook-based beamforming has been recently proposed 2 Wireless Communications and Mobile Computing as an efficient method to reduce the dependency on CSI estimation/feedback [6,7]. Also, several works have been presented on both physical layer and procedural algorithms of IA beamforming [8][9][10][11][12][13][14][15]. However, in these works either the algorithms are designed for special metrics, precoding/combining schemes, and channel models or the implementation complexity grows significantly by an increasing number of BSs/users.…”

Graph-based model for beam management in Mmwave vehicular networks

“…In [15] the authors present a framework that combines matching theory and swarm intelligence to dynamically and efficiently perform user association and beam alignment in a vehicle-to-vehicle communication network. Methods aided by location information have been proposed in [14], as have methods which use information from road-side and vehicle sensors [2,8]. In our own previous work [13], a method leveraging traffic regulating signals was proposed to alleviate the need for real-time beam realignment.…”