| 1. |
- Lu, Rui, et al.
(författare)
-
Direction-of-Arrival Estimation in the Presence of Phase Noise
- 2020
-
Ingår i: IEEE Communications Letters. - 1558-2558 .- 1089-7798. ; 24:8, s. 1710-1714
-
Tidskriftsartikel (refereegranskat)abstract
- This letter proposes a robust direction-of-arrival (DoA) estimator in the presence of phase noise (PN). For a multi-antenna system with independent oscillators, the received signals will be corrupted by multiple independent PN sources, resulting in severe performance degradation of the DoA estimator, especially for millimeter-wave systems. However, due to the time-varying nature of PN, the number of associated unknowns grows with the size of the snapshots, making the calibration challenging. To tackle this problem, we use a piece-wise linear model to approximate PN so that the number of associated unknowns can be reduced. Then we estimate the DoA and the PN parameters iteratively via a nonlinear least squares estimator. To evaluate the effectiveness of the proposed scheme, the Cramer-Rao lower bound (CRLB) of the DoA estimation in the presence of PN is derived. Numerical results show a significant performance improvement of the proposed DoA estimator compared to the results without calibration.
|
|
| 2. |
- Xiaoming, Chen, 1983, et al.
(författare)
-
Characterizations of Mutual Coupling Effects on Switch-Based Phased Array Antennas for 5G Millimeter-Wave Mobile Communications
- 2019
-
Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 7, s. 31376-31384
-
Tidskriftsartikel (refereegranskat)abstract
- The fifth generation (5G) millimeter-wave (mmWave) handset demands a cost-effective mmWave array antenna with beam steering capability to overcome the high-pass loss and to ensure seamless connectivity. Unlike sub-6-GHz handsets, emerging mmWave handsets usually employ phased array antennas with a reasonably large number of elements. Unfortunately, due to the legacy of a few antennas in sub-6-GHz handsets, the mutual coupling effect on the mmWave handset has not been thoroughly investigated. In this paper, we study the mutual coupling effect on the mmWave handset performance by comparing array antennas with different inter-element spacing and different configurations. It is found that mutual coupling tends to increase the active reflection (especially at large scanning angles), which in turn reduces the realized gain and maximum scanning angle of the phased array antenna. For a sub-6-GHz multiple-input multiple-output handset with two or four antenna ports and fully digital precoding/decoding, 10-dB isolation is usually regarded as good enough. It is shown in this paper, however, that the outage capacity of the mmWave handset can be clearly improved by reducing the mutual coupling.
|
|
| 3. |
- Xue, Wei, et al.
(författare)
-
A Unified Approach for Uncertainty Analyses for Total Radiated Power and Total Isotropic Sensitivity Measurements in Reverberation Chamber
- 2021
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - 1557-9662 .- 0018-9456. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- With the rapid development and explosive application of the Internet of Things (IoT) technology, IoT devices become ubiquitous and indispensable in people’s daily lives. IoT devices with various forms and massive production impose challenges on their over-the-air (OTA) testing. Nowadays, conducting OTA testing in an efficient, reliable, and cost-effective way has become an urgent demand for the IoT industry. Owing to the particular properties (e.g., low cost, high efficiency, and good repeatability) of the reverberation chamber (RC), it has become a popular OTA testing facility. This paper analyzes the statistical uncertainties of two fundamental metrics for IoT devices, i.e., the total radiated power (TRP) and the total isotropic sensitivity (TIS), measured in the RC. Based on the derived probability density functions (PDFs) and associate statistics, a unified approach for uncertainty analyses of TRP and TIS has been proposed, which can greatly facilitate the uncertainty characterizations in the OTA testing.
|
|
