Youngpo Lee

Cancellation of Correlation Side-Peaks for Unambiguous BOC Signal Tracking

Based on a combination of the sub-correlation functions composing the autocorrelation of the binary offset carrier (BOC), we propose a novel cancellation scheme of correlation side-peaks to solve the ambiguity problem in the BOC signal tracking. The proposed scheme is applicable to both generic sine- and cosine-phased BOC signals without requiring any auxiliary signal in the receiver. Avoiding the ambiguity problem, the proposed scheme is confirmed from numerical results to provide a better tracking accuracy than the conventional schemes.

Code Tracking Scheme for Cosine Phased BOC Signals Based on Combination of Sub-correlations

In this paper, we propose a novel unambiguous code tracking scheme for cosine phased binary offset carrier (BOC) signals. We first obtain the sub-correlation functions composing the BOC autocorrelation function, and then, re-combine the sub-correlation functions generating a correlation function with no side-peak. Finally, by using the correlation function with no side-peak in the delay lock loop, the proposed scheme performs unambiguous signal tracking. Numerical results demonstrate that the proposed scheme provides a performance improvement over the conventional unambiguous scheme in terms of the tracking error standard deviation (TESD).

AltBOC and CBOC Correlation Functions for GNSS Signal Synchronization

Binary offset carrier (BOC) signal synchronization is based on the correlation between the received and locally generated BOC signals. Thus, the multiple side-peaks in BOC autocorrelation are one of the main error sources in synchronizing BOC signals. Recently, new correlation functions with no side-peak were proposed for sine and cosine phased BOC signal synchronization, respectively, by the authors [3]. In this paper, we propose new correlation functions with no side-peak for alternative BOC (AltBOC) and composite BOC (CBOC) signals by using the similar approach to the previous work.

Symbol error rate of the dm-mpsk under the influence of jamming signals

Focusing on the performance of the chirp spread spectrum (CSS) communication system under the influence of jamming, we analytically derive the symbol error rate (SER) for the direct modulation CSS system with M-ary phase shift keying in the presence of broadband and tone jamming signals. From numerical results, it is confirmed that the analytic result agrees closely with the empirical SER.

A distance measuring scheme based on repeated use of PN sequence

This paper proposes a novel distance measuring scheme based on repeated PN sequence for ultra wide-band vehicle radar systems. The proposed scheme measures the distance between a vehicle and an obstacle based on repeated use of a single short pseudo random sequence. Simulation results show that the proposed scheme provides a shorter mean distance measuring time while keeping a similar measurement error performance to that of the conventional scheme.

Synchronization Technique Based on Adaptive Combining of Sub-correlations of Multiband Sine Phased BOC Signals

This paper addresses a synchronization technique based on an adaptive combining of the sub-correlation functions obtained from multiband sine phased binary offset carrier (BOC) signals, allowing a BOC signal receiver to deal with multiband sine phased BOC signals. Specifically, we first obtain the sub-correlation functions composing the BOC autocorrelation function, and then, re-combine the sub-correlation functions generating a correlation function with no side-peak. Finally, by replacing the BOC autocorrelation with the correlation function with no side-peak in the delay lock loop, the proposed scheme performs unambiguous signal tracking. The proposed synchronization scheme is applicable to generic sine phased BOC signals. Numerical results demonstrate that the proposed scheme provides a performance improvement over the conventional unambiguous schemes in terms of the tracking error standard deviation.

Performance Analysis of a CSS System with M-ary PSK in the Presence of Jamming Signals

Due to its anti-jamming capability, chirp spread spectrum (CSS) technique has attracted much attention in the area of wireless communications. However, there has been little rigorous analysis for the performance of the CSS communication system in the presence of jamming signals. In this paper, we present analytic results on the performance of a CSS system: symbol error rate (SER) expressions are derived for a CSS M-ary phase shift keying (MPSK) system in the presence of broadband and tone jamming signals, respectively. The numerical results show that the empirical SER closely agrees with the analytic result.

An Alamouti Coding Scheme for Asynchronous Cooperative Communication Systems over Frequency Selective Fading Channels

This paper addresses a novel Alamouti coding scheme for asynchronous cooperative communication systems over frequency selective fading channels. In the proposed scheme, the Alamouti coded form at the destination node is constructed through a simple combination of symbols at the source node, instead of the time-reversal operation at the relay nodes used in the conventional scheme. Numerical results show that the proposed scheme achieves a higher order cooperative diversity than that of the conventional scheme.

A two-stage acquisition scheme based on multiple correlator outputs for UWB signals

In ultra-wideband (UWB) channels, the signal energy in the acquisition receiver spreads over correlator outputs due to rich multipaths, making the output of each correlator have only a small portion of the total energy. To enhance the acquisition performance for UWB signals by exploiting the signals spread over a number of correlator outputs, this paper proposes a two-stage acquisition scheme. In the proposed scheme, decision variables are formed by combining a multiple of correlator outputs, allowing it possible to make use of the signal energy spread over the outputs jointly. Simulation results show that the proposed scheme can provide a gain of about 0.6dB over the conventional schemes in various UWB channel environments.

Low Complexity Sequential Estimation Scheme for Pseudo Noise Code Acquisition

In this paper, a low complexity sequential estimation scheme for pseudo noise (PN) code acquisition is proposed, which can not only achieve code acquisition for both inverted and non-inverted PN codes, but also demodulate the spreading data. Numerical results show that the proposed scheme has approximately half the complexity of the conventional scheme while exhibiting a similar mean acquisition time performance to that of the conventional scheme.