Seungsoo Yoo

A novel PAPR reduction scheme for OFDM systems: selective mapping of partial tones (SMOPT)

A novel scheme called the selective mapping of partial tones (SMOPT) is addressed for the reduction of the peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. The SMOPT first produces a set of modified OFDM symbols with reduced PAPRs by adding a set of mapping symbols designed on peak reduction tones (PRT) to the original OFDM symbol. The SMOPT then selects the symbol with the lowest PAPR for transmission among the modified OFDM symbols. When simulated under the IEEE 802.11a wireless local area network and ETSI EN 300 401 digital audio broadcasting physical layer models, the SMOPT is observed to have lower sensitivity to PRT positions, lower complexity, and more design flexibility than the tone reservation scheme.

A Novel Unambiguous Multipath Mitigation Scheme for BOC(kn, n) Tracking in GNSS

Binary offset carrier (BOC) signal tracking is one of the challenging problems in future Global Navigation Satellite Systems (GNSS) including Galileo and Global Positioning System (GPS), because false lock could be generated in the tracking procedure due to multiple side-peaks in BOC autocorrelation. Multipath mitigation is another challenging problem in GNSS systems, because the presence of multi-path signals gives a range error. Recently, a novel tracking scheme for the BOC signal was proposed by Garin. However, it cannot completely resolve the ambiguity problem due to the false lock and has not enough multipath mitigation performance. Moreover, Garins scheme is applicable to only BOC (n, n). In this paper, we propose a novel unambiguous multipath mitigation scheme. The proposed scheme is applicable to various BOC signals (i.e., BOC (kn, n)) and does not incur false lock point in the tracking procedure. In addition, the proposed scheme has appropriate multipath mitigation performance than traditional and Garins schemes

A novel multipath mitigation scheme based on slope differential of correlator output for Galileo systems

In this paper, we propose a novel multipath mitigation scheme based on the slope difference of the correlator output between the received and locally generated reference signals. Since the proposed scheme employs only the prompt correlator, it does not require a high speed digital signal processing for the narrow early-late spacing, unlike the narrow correlator (NC) and strobe correlator (SC). Moreover, in the presence of the multipath, the proposed scheme has an unbiased tracking error, whereas the NC and SC schemes have a biased tracking error due to the non-symmetric property of the correlation output

New Correlation Functions for CBOC Satellite 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, a new correlation function with no side-peaks was proposed for sine or cosine phased BOC signal synchronization by the authors [7]. In this paper, we propose a novel correlation function for composite binary offset carrier (CBOC) signals by using the similar method to that in [7], which has a better power ratio than the CBOC autocorrelation.

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.

A Novel Time Delay Estimation Bias Reduction Scheme using Maximum Slope Change in GNSS

The early minus late discriminator based delay locked loop (EL-DLL), which is a general code tracking scheme of the global navigation satellite system (GNSS), has enormous time delay estimation bias (beta). The narrow correlated DLL (NC-DLL) and the double delta DLL (Delta(2)-DLL) were proposed as a beta reduction scheme, where Delta means the spacing between early and late correlation sample. However, the two schemes cannot remove the beta completely and make the dynamic range narrower than the EL-DLL, which lead to very accurate acquisition. This paper proposes a novel tracking scheme that can reduce the beta using maximum slope change without narrow dynamic range.

A Novel Scheme for Positioning Error Mitigation in OFDM-Based on Wireless Location Systems

This paper proposes a novel scheme for positioning error mitigation in orthogonal frequency division multiplexing (OFDM)-based wireless location systems. The proposed scheme combines the cell ID and the time-difference-of-arrival (TDoA) schemes. These two schemes have mutually complementary characteristic. In the proposed scheme, one of the two schemes is selected and used for positioning error mitigation, according to the received signal strength (RSS) due to Delta, where Delta denotes the distance between a base station (BS) and a mobile station (MS).

Performance of Code Synchronization Schemes using Chip Waveform Shaped Code on DS/SS System in Multipath Environments

This paper analyzes the tracking performance of a delay lock loop (DLL) using chip waveform shaped code on direct sequence/spread spectrum (DS/SS) systems in multipath environments. In this paper, chip waveform shaping (CWS) filters consider a rectangular (RECT) filter and a raised cosine (RC) filter. It is assumed that a tracking scheme for code synchronization in a DS/SS system uses a single delta DLL (Delta-DLL). Here, Delta means the spacing between early and late correlation values.

A novel unambiguous composite binary offset carrier(6,1,1/11) tracking based on partial correlations

An unambiguous tracking scheme is proposed for CBOC(6,1,1/11) signal.The proposed scheme combines the partial correlations in a specially designed way.The autocorrelation side-peaks are completely removed by the proposed scheme.Better TESD and MEE performances are achieved over those of the conventional schemes. This paper proposes a novel unambiguous correlation function for composite binary offset carrier (CBOC) signal tracking based on partial correlations. In the proposed scheme, first, we partition sub-carriers of the CBOC signal into partial sub-carriers, and subsequently, we obtain partial correlations by correlating the partial sub-carriers with the received CBOC signal. Finally, a novel unambiguous correlation function with no side-peak is constructed by combining the partial correlations in a specially designed way. Unlike the conventional schemes, the proposed scheme does not require any auxiliary signal and from numerical results, it is found to offer a better tracking performance than those of the conventional schemes in terms of the tracking error standard deviation (TESD) and multipath error envelope (MEE).

A Novel Repeat-back Jamming Detection Scheme for GNSS using a Combined Pseudo Random Noise Signal

A repeat-back jamming signal is an intentionally re-broadcasted GNSS (Global Navigation Satellite System) interference. In this paper, a novel repeat-back jamming detection scheme is proposed. The proposed scheme uses a combined pseudo random noise signal (C-PRN) and is available for a generic GNSS receiver with a single antenna. The C-PRN signal is made by combining several received pseudo random noise signals that had been transmitted from the visible GNSS satellites. Through a Monte-Carlo simulation, the detection probability of a repeat-back jamming signal detected with the proposed scheme is presented.