5 papers
Experimental Comparison of Local and Over-the-Air Phase Calibration for MIMO Arrays
Carl Collmann, Ahmad Nimr, Gerhard Fettweis
Communication performance and channel estimation accuracy in MIMO systems are known to be limited by hardware impairments. Specifically, the presence of phase impairments, such as…
Estimating PLL Phase Noise Parameters from Measurements for System-Level Modeling
Carl Collmann, Ahmad Nimr, Gerhard Fettweis
In current MIMO mobile communication systems, phase noise can significantly impair performance. To allow for compensation of these impairments, accurate phase noise modeling is nec…
Proof of Concept: Local TX Real-Time Phase Calibration in MIMO Systems
Carl Collmann, Ahmad Nimr, Gerhard Fettweis
Channel measurements in MIMO systems hinge on precise synchronization. While methods for time and frequency synchronization are well established, maintaining real-time phase cohere…
Cramer-Rao Bound for Angle of Arrival Estimates in True-Time-Delay Systems
Carl Collmann, Ahmad Nimr, Gerhard Fettweis
In the context of joint communication and sensing JC&S, the challenge of obtaining accurate parameter estimates is of interest. Parameter estimates, such as the AoA can be utilized…
A Practical Analysis: Understanding Phase Noise Modelling in Time and Frequency Domain for Phase-Locked Loops
Carl Collmann, Bitan Banerjee, Ahmad Nimr +1
In MIMO systems, the presence of phase noise is a significant factor that can degrade performance. For MIMO testbeds build from SDR devices, phase noise cannot be ignored, particul…