# Analysis of Beam Sweeping Techniques for Cell-Discovery in mm Wave Systems

## TL;DR

This paper analyzes beam sweeping techniques for cell discovery in mmWave systems, focusing on performance modeling, overhead reduction, and the impact of multiple base stations using simulations.

## Contribution

It provides a mathematical and analytical framework for beam sweeping and combining methods, including performance evaluation in single and multiple BS scenarios.

## Key findings

- Beam combining reduces training overhead.
- Performance depends on channel conditions and beam parameters.
- Simulation results validate analytical models.

## Abstract

Cell discovery is the procedure in which a user equipment (UE) finds a suitable base station (BS) to establish a communication link. When beamforming with antenna arrays is done at both transmitter and receiver, cell discovery in mm wave systems also involves finding the correct angle of arrival - angle of departure alignment between the UE and the detected BS. First, we consider the single BS scenario and present the mathematical model for the cell discovery problem. We present the details of the beam sweeping based techniques and explain the beam combining scheme to reduce the training overhead. We analytically characterize the performance of energy detector at the UE for both beam sweeping and beam combining methods under some channel assumptions. Further, we consider the multiple BS case where BSs transmit synchronization signals along with directional beamforming. We analyze the performance of the energy detector in this case as well. We finally present simulation studies with channels generated using generic mm wave channel emulators and draw inferences on the role of various parameters on the cell discovery performance.