Field-Measurement-Based Received Power Analysis for Directional Beamforming Millimeter-Wave Systems: Effects of Beamwidth and Beam Misalignment

Abstract

To overcome considerable path loss in millimeterwave propagation, high-gain directional beamforming is considered to be a key enabling technology for outdoor 5G mobile networks. Associated with beamforming, this paper investigates propagation power loss characteristics in two aspects. The first is beamwidth effects. Owing to the multipath receiving nature of mobile environments, it is expected that a narrower beamwidth antenna will capture fewer multipath signals, while increasing directivity gain. If we normalize the directivity gain, this narrowbeamwidth reception incurs an additional power loss compared to omnidirectional-antenna power reception. With measurement data collected in an urban area at 28 GHz and 38 GHz, we illustrate the amount of these additional propagation losses as a function of the halfpower beamwidth. Secondly, we investigate power losses due to steering beam misalignment, as well as the measurement data. The results show that a small angle misalignment can cause a large power loss. Considering that most standard documents provide omnidirectional antenna path loss characteristics, these results are expected to contribute to mmWave mobile system designs.

Radio propagation measurements and modeling for standardization of the site general path loss model in International Telecommunications Union recommendations for 5G wireless networks

“…To capture the effects of the antenna and cable connections, an open-area calibration along a straight-line road is conducted using an identical setup to that employed in the field measurements. Figure 6 shows that the calibrated open-area path loss follows the theoretical two-ray model where the discrepancies are attributed to the nature of the road in the open area (Lee et al, 2018).…”

Millimeter‐wave directional‐antenna beamwidth effects on the ITU‐R building entry loss (BEL) propagation model

“…in Figure 5 indicate the direction and strength of the received power, respectively. Because of the outage issues with the wide beamwidth antenna measurements (not only the omnidirectional antenna but also the 30° and 60° horns), we apply the beam synthesis algorithm [5] to generate the other beamwidth BEL characteristics, while utilizing the un-outaged 30°-horn, 60°-horn, and omnidirectional antenna measurements for beam synthesis calibration. The "×" marks in the figures denote outages.…”

“…We applied the beamwidth-synthesis algorithm in [5] to generate the beamwidth-dependent directional BEL characteristics. One key idea of the beamwidth-synthesis algorithm is the consideration of pointing the antenna boresight to the maximum power direction, which is dependent on the operating beamwidth.…”

“…It is known that the propagation characteristics captured with a narrow-beamwidth antenna are different from those captured with an omnidirectional antenna, especially in multipath-rich environments due to spatial filtering effects [5], and therefore, the BEL model will be affected when receiving with a narrow-beamwidth antenna since receivers are typically located in multipath-rich indoor environments. It is known that the propagation characteristics captured with a narrow-beamwidth antenna are different from those captured with an omnidirectional antenna, especially in multipath-rich environments due to spatial filtering effects [5], and therefore, the BEL model will be affected when receiving with a narrow-beamwidth antenna since receivers are typically located in multipath-rich indoor environments.…”

A 1‐W Ka‐band power amplifier using 0.15‐μm InGaAs/GaAs E‐mode pHEMT technology

“…Currently, several monolithic microwave integrated circuits (MMICs) for the 5G communication have been actively implemented at a Ka-band because the frequency around 28 GHz has advantages of light weight of antennas due to a short wavelength and gigabit data transmission due to wide bandwidth. [1][2][3][4][5][6][7] Also, as shown in Figure 1, a 28 GHz phasearrayed transceiver system is being actively studied as a technology to improve the communication efficiency. 8,9 In response to this demand, the Ka-band MMIC capable of high-performance and low-cost mass production has been developed.…”