Maximum-Likelihood-Based Location, Orientation, Transmitted Power, and Antenna Beamwidth Estimator Utilizing the Angle-of-Arrival and Received Power for Spectrum Sharing at Millimeter Wave Bands

Abstract

The fifth-generation (5G) system utilizing millimeter wave is available in Japan, but more bandwidth is demanded by the mobile phone operators to accommodate the demand for high data rate. Allocation of the vacant spectrum is impossible due to the past spectrum allocation to other radio systems. For example, 24.25-27.5 GHz has been allocated for the fixed wireless access (FWA) and license exempt small power data communication system in Japan. Although Japanese government is considering to license a part of the band for 5G under the spectrum sharing scheme, the coexistence design is quite challenging due to unavailable operation data of such systems in a form of database for the coexistence study. For this purpose, this paper introduces a maximum-likelihood estimator (MLE), which utilizes the angle-of-arrival (AoA) and received power of the line-of-sight (LOS)/diffraction paths as well as the map database to simultaneously estimate these unknown parameters via the spectrum sensing. It was applied to the measurement data obtained from a sub-urban environment where a commercial fixed wireless access system with similar operational parameters is under operation. Its performance was evaluated for a different number of receiver (Rx) points. The results showed that the parameter estimation accuracy is proportional to the number of receiver points. The distance and orientation errors of 45 m and 5 deg were achieved at 90th percentile with 40 Rx points. Furthermore, the prediction performance of the effective isotropic radiated power (EIRP) was decent, albeit a slight underestimation of the beamwidth.

Experimental Demonstration of Wave Source Location Estimation Method for Spectrum Sharing in 28-GHz-Band 5G System

“…Table 1 lists the existing studies on the wave source location estimation. The source location estimation method is classified into three approaches: RSS [19], [20], [21], [22], TDOA [23], [24], and DOA [18], [25], [26], [27], [28], [29], [30], [31]. A comprehensive performance comparison of these approaches in millimeter-wave band wireless systems was presented in [32].…”

“…Furthermore, in the spectrum sharing, a secondary system does not interfere with a primary system in principle, and hence it is necessary to obtain the radio wave source location information of the primary system for interference coordination. However, the location information may not be available or disclosed for temporary or license-exempt system, because it is not recorded in the database [18]. Thus, several approaches for wave source location estimation, such as received signal strength (RSS) [19], [20], [21], [22], time difference of arrival (TDOA) [23], [24], and direction of arrival (DOA) [18], [25], [26], [27], [28], [29], [30], [31], have been studied.…”

“…However, the location information may not be available or disclosed for temporary or license-exempt system, because it is not recorded in the database [18]. Thus, several approaches for wave source location estimation, such as received signal strength (RSS) [19], [20], [21], [22], time difference of arrival (TDOA) [23], [24], and direction of arrival (DOA) [18], [25], [26], [27], [28], [29], [30], [31], have been studied. From a practical point of view, the DOA-based approach is considered as a promising technique that realizes the high estimation accuracy [32].…”

“…From a practical point of view, the DOA-based approach is considered as a promising technique that realizes the high estimation accuracy [32]. The performance of the DOA-based wave source location estimation has been experimentally investigated in the sub-6 GHz band [27], [28], [29], [30] and in the millimeter-wave band [18], [31]. The authors in [18] and [31] focused on fixed wireless systems and proposed a method for estimating parameters including wave source location.…”

“…The performance of the DOA-based wave source location estimation has been experimentally investigated in the sub-6 GHz band [27], [28], [29], [30] and in the millimeter-wave band [18], [31]. The authors in [18] and [31] focused on fixed wireless systems and proposed a method for estimating parameters including wave source location. However, to the best of our knowledge, no existing literature has designed the wave source location estimation for actual 5G base stations (BSs) in the millimeter-wave band.…”