Downlink multi-user algorithms for millimeter-wave wideband linear arrays on PD-NOMA-based squint steering beams

Xiaoliang Pan,Luxi Yang

doi:10.1186/s13634-021-00772-0

Xiaoliang Pan, Luxi Yang

Open Access

https://doi.org/10.1186/s13634-021-00772-0

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Abstract

This article investigates using a phased linear antenna array instead of the planar array to circumvent the problem that two frequency squint steering main beams cannot cover any two beam directions simultaneously. First, we approximate the donut-shaped main beam of the linear array by means of multiple pencil-shaped main beams of a virtual planar array for matching the steering main beam of the linear array with the multi-path sparse scattering channel model mathematically and give a method for calculating the number of antenna elements of the virtual array. Second, we cope with possible inter-user interference on a single squint main beam of the linear array in some scenarios by means of the power-domain non-orthogonal multiple access (PD-NOMA) technique, making it possible to support communication with two users on a single squint main beam at the base station (BS) side. The feasible domain of PD-NOMA is given when a single antenna is used for both the BS and the user end, assuming a two-user successive interference cancellation (SIC) decoding power ratio limit. Third, three algorithms are given for serving multi-user at the BS via squint beams of the linear array. Finally, numerical results show that the second proposed algorithm supporting PD-NOMA pairing within a single donut-shaped squint main beam significantly increases the number of simultaneous users served within a single cellular system.

Highlights

Wideband millimeter-wave communications have received increasing attention in recent years, and the beam squint problem caused by phase differences between frequencies in the radio frequency (RF) analog domain induced by the utilization of nonideal wideband phase shifters is one of the important problems encountered [1,2,3]
The array factor and channel path are generally described by one angular parameter in a 2-D scenario [6], which is more convenient and concise to describe the nature of the array, but the main direction of the steer beam of a linear array is donut-shaped in 3D space, so there may exist scattering paths at different horizontal azimuths, where the angle-of-departure (AoD) of a particular channel path is within the angular range of the transmitting donut-shaped main beam
4 Results and discussion The simulations are based on a uni-cell scenario with one base station (BS) and multiuser, where the BS side consists of a linear array of Nt antenna elements, the total number of users is Nu and each user end uses a square planar array with Mr elements on each side, and all transceivers are wideband phased antenna arrays with central frequency fc of 45 GHz and element spacing of λc/2

Summary

Introduction

Wideband millimeter-wave (mmWave) communications have received increasing attention in recent years, and the beam squint problem caused by phase differences between frequencies in the radio frequency (RF) analog domain induced by the utilization of nonideal wideband phase shifters is one of the important problems encountered [1,2,3]. In step 5, the elevation angle space at the transmitter end is divided into angular regions by the HPBW h at the central frequency of the PU, with each region supporting at most one donut-shaped squint main beam within the angular range, and each steering beam serving at most one user at a time. It is obtained from (6) and (7) resulting in h fc ≈ arccos cos (35).

14: Executes Steps 6-8 in Algorithm 1 for user 2

Results and discussion

Conclusion