Presence Of Oscillator Phase Noise Research Articles

Continuous Analog Channel Estimation-Aided Beamforming for Massive MIMO Systems

Analog beamforming greatly reduces the implementation cost of massive antenna transceivers by using only one up/down-conversion chain. However, it incurs a large pilot overhead when used with conventional channel estimation (CE) techniques. This is because these CE techniques involve digital processing, requiring the up/down-conversion chain to be time-multiplexed across the antenna dimensions. This paper introduces a novel CE technique, called continuous analog channel estimation (CACE), that avoids digital processing, enables analog beamforming at the receiver and additionally provides resilience against oscillator phase-noise. By avoiding time-multiplexing of up/down-conversion chains, the CE overhead is reduced significantly and furthermore becomes independent of the number of antenna elements. In CACE, a reference tone is transmitted continuously with the data signals, and the receiver uses the received reference signal as a matched filter for combining the data signals, albeit via analog processing. We propose a receiver architecture for CACE, analyze its performance in the presence of oscillator phase-noise, and derive near-optimal system parameters and power allocation. Transmit beamforming and initial access procedure with CACE are also discussed. Simulations confirm that, in comparison to conventional CE, CACE provides phase-noise resilience and a significant reduction in the CE overhead, while suffering only a small loss in signal-to-interference-plus-noise-ratio.

Performance analysis of distributed transmit beamforming in presence of oscillator phase noise

This paper analyses the performance of distributed transmit beamforming in presence of oscillator phase noise. Average beampattern of arbitrary array is adopted here as performance index. In the analysis, the phase noise process of each node oscillator is described by a stationary model taking into account 1/f3 and 1/f2 shape single-sideband (SSB) spectrum. By using non-parametric kernel method, the average beampattern in presence of phase noise is derived and corresponding beampattern characteristics are evaluated. Theoretical analysis and simulation results show that the accumulated PN can result in the degradation of DTBF performance, which are also reflected in the change of beampattern characteristics, such as 3db width, 3db sidelobe region and average directivity. With the increase of time duration, the cumulative phase noise becomes greater and the degradation is more obvious.

Performance analysis of distributed transmit beamforming in presence of oscillator phase noise

This paper analyses the performance of distributed transmit beamforming in presence of oscillator phase noise. Average beampattern of arbitrary array is adopted here as performance index. In the analysis, the phase noise process of each node oscillator is described by a stationary model taking into account 1/f3 and 1/f2 shape single-sideband (SSB) spectrum. By using non-parametric kernel method, the average beampattern in presence of phase noise is derived and corresponding beampattern characteristics are evaluated. Theoretical analysis and simulation results show that the accumulated PN can result in the degradation of DTBF performance, which are also reflected in the change of beampattern characteristics, such as 3db width, 3db sidelobe region and average directivity. With the increase of time duration, the cumulative phase noise becomes greater and the degradation is more obvious.

Dual transponder ranging performance in the presence of oscillator phase noise

A dual transponder carrier ranging method can be used to measure inter-satellite distance with high precision by combining the reference and the to-and-fro measurements. Based on the differential techniques, the oscillator phase noise, which is the main error source for microwave ranging systems, can be significantly attenuated. Further, since the range measurements are derived on the same satellite, the dual transponder ranging system does not need a time tagging system to synchronize the two satellites. In view of the lack of oscillator noise analysis on the dual transponder ranging model, a comprehensive analysis of oscillator noise effects on ranging accuracy is provided. First, the dual transponder ranging system is described with emphasis on the detailed analysis of oscillator noise on measurement precision. Then, a high-fidelity numerical simulation approach based on the power spectrum density of an actual ultra-stable oscillator is carried out in both frequency domain and time domain to support the presented theoretical analysis. The simulation results under different conditions are consistent with the proposed concepts, which makes the results reliable. Besides, the results demonstrate that a high level of accuracy can be achieved by using this oscillator noise cancelation-oriented ranging method.

PLL Tracking Performance in the Presence of Oscillator Phase Noise

The tracking performance of a Phase Lock Loop (PLL) is affected by the influence of several error sources. In addition to thermal noise and dynamic stress error, oscillator phase noise can cause significant phase jitter which degrades the tracking performance. Oscillator phase noise is usually caused by two different effects: Allan deviation phase noise is caused by frequency instabilities of the receiver's reference oscillator and the satellite's frequency standard. It can be termed as system-inherent phase noise and is relevant for both static and dynamic applications. “External” phase noise, however, is caused by vibration and is a major problem for dynamic applications. In the context of this paper, both types of phase noise will be modeled and the resulting integrals will be evaluated for PLLs up to the third order. Besides, phase jitter induced by thermal noise and signal dynamics will also be discussed, thus providing all necessary formulas for analyzing the performance of a phase lock loop in case of different forms of stress. Since the main focus is centered on the effects of oscillator phase noise, the overall PLL performance is graphically illustrated with and without consideration of oscillator phase noise. © 2002 Wiley Periodicals, Inc.

The performance of coherent BPSK in the presence of oscillator phase noise for ka-band pico-terminal inbound links

In microwave systems, the phase noise is well known to be a significant source of degradation especially for low data rate transmission, giving rise to a significant irreducible error rate. In an earlier study [1,2] based on the European Space Agency's Olympus Satellite 30/20 GHz payload parameters, it was found that several thousands of simultaneous transmissions of 50 to 200 bits/sec each could be supported from hand-held pico-terminal earth stations. It is important to use the most appropriate modulation scheme in the presence of oscillator phase noise for such low data rate systems. It is generally assumed that noncoherent or differentially coherent modulation schemes will perform best in applications where the coherence time of the oscillators is short compared to the bit period. However, our analysis of these schemes has shown that they are subject to irreducible error rates and minimum useable data rates. This has led us to reconsider coherent BPSK (CPSK). It is shown that the choice of the optimum noise bandwidth of the phase locked loop (PLL) in the carrier recovery circuit is very important when considering the coherent schemes. The PLL bandwidth must be wide enough to track the oscillator phase noise at its input, but, on the other hand, it must be as narrow as possible to exclude the thermal noise. Results show that coherent BPSK in the phase noise contaminated channel is also subject to an irreducible error rate, which increases as the noise bandwidth is reduced. For the optimum loop bandwidth, however, this appears to be lower than the corresponding figure for DPSK [3]. There is a minimum useable data rate for any given bit error rate (BER) requirement. Results of a complete analysis are presented in the form of BER versusE b/N o plots.

Error probability evaluation in the presence of microwave oscillator phase noise

This work presents the theoretical calculation of the error probability as a function of the signal to noise ratio in presence of the oscillator phase noise in the 4 PSK and 16, 64, 256 and 1024 QAM systems. Experimental verifications confirm the computed values. On the basis of the procedure described herein, the design of two oscillators that operate in different modulation and capacity systems and with different values of the oscillation frequency is illustrated.