Inexpensive upgrade of base-station dumb antennas by two magnetic loops for "blind" adaptive downlink beamforming

Abstract

A simple scheme is herein proposed to upgrade an older base-station's "dumb" antennas for use in an adaptive space-division frequency-reuse downlink, with no expensive retrofitting of each "dumb" antenna with its own rake receiver. This scheme adds only two horizontally oriented loops (plus an optional vertically oriented dipole) to a base station's 120°-azimuth sector, each with a temporal (not space-time) rake receiver. Such a pair (or triad) of diversely polarized but collocated antennas can estimate an incident mobile-source's uplink direction of arrival, based on which the existing "dumb" antennas can beam-form towards the mobile in downlink transmission.

Various Compositions to Form a Triad of Collocated Dipoles/Loops, for Direction Finding and Polarization Estimation

“…4) The {e z , h x , h y } triad has been investigated in [25]- [29], with closed-form estimation formula available for the azimuth arrival angle in [26], but no closedform estimation formula is available for the elevation 1 Real antenna patterns depend on frequency. The array manifold would not depend on frequency if all antennas have the same frequency-dependence.…”

Estimation Algorithm of Incident Sources' Stokes Parameters and 2‐D DOAs Based on Reduced Mutual Coupling Vector Sensor

“…However, the RMCVS has a larger size and the spatial phase shifts could add the complexity. Comparing with the antenna array used in Wong and Yuan (2011), Song et al (2014), , Wong and Lai (2005), Wong (1999), Li and Stoica (1994), Chang, Ru, et al (2018), Chang, Li, et al (2018), He et al (2013), and , the manifold of the RMCVS is better suited for a biquaternion-based representation.…”

“…When the EMVS was first introduced, a cross-product-based DOA estimation algorithm being applicable to single-source scenarios was proposed (Nehorai & Paldi, 1994). By using the EMVS or its variations, subsequently, many DOA estimation algorithms applied to different scenarios have Radio Science 10.1029/2019RS006796 been developed in Au-Yeung and Wong (2009), Costa et al (2012), Khan et al (2018), Kitavi et al (2017), Song et al (2014), Wong (2001aWong ( , 2001b, Wong and Lai (2005), Wong and Yuan (2011), Wong and Zoltowski (1997), Wong et al (2017), Yuan (2012), , and Yuan, Wong, Xu, et al (2012). To estimate DOA and polarization, a six-component EMVS is exploited in Wong and Zoltowski (1997) and Yuan (2012).…”

A Joint Parameter Estimation Method With Conical Conformal CLD Pair Array

“…The problem of estimating signal polarizations along with arrival angles has been discussed previously in many articles [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The first direction-finding algorithms, explicitly exploiting all six electromagnetic components, have been developed by Nehorai and Paldi [1,2] and Li [4], respectively.…”

“…In fact, the aforementioned literatures mostly discuss the six collocated and orthogonally oriented electromagnetic sensors, which is called "complete" EMVS. The "incomplete" EMVS antenna configuration has been extensively studied by many authors, such as two identical dipoles [9][10][11], two identical loops [12,13], triad dipole or triad loop [14,15], etc. [16,17].…”