• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.1C
• /
• pp.81-89
• /
• 2009

We propose a D-ATR UWB (Differential-Average Transmitted Reference Ultra Wide Band) system based on impulse radio. The TR-UWB systems including traditional TR (Transmitted Reference) and ATR (Average TR), exhibit a problem of reduced data rate, since reference signals are additionally transmitted. To tackle this issue, the transmitter of the proposed D-ATR system employs a differential coding like the conventional D-TR system. In addition, the receiver of the proposed system has the structure that can improve signal-to-noise ratio of the reference template used in the correlation process, by recursively averaging the received reference signals like the conventional ATR system. The simulation results in the IEEE 802.15.4a UWB multipath channel models reveal that the proposed D-ATR system achieves much better bit error rate performance as compared to the conventional D- TR system.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.5 no.1 s.9
• /
• pp.45-54
• /
• 2006

The UWB signal distortion in frequency selective channel has made it difficult to implement the channel estimator and the synchronizer of the UWB receiver. In this paper, we examine the performances of TR(Transmitted Reference) and DTR(Differential TR) UWB which use either reference pulse or differential method to estimate the channels. we also propose a FSK-based PRM(Pulse Repetition Modulation) UWB system as an another form of UWB system which is advantageous in frequency selective channel. Finally, resorting to statistical analysis, we examine the noise effect due to noisy reference at an auto-correlation(AcR) receiver. moreover, SNR dependance of the integration length in the AcR receiver is also investigated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.05a
• /
• pp.985-988
• /
• 2008

This paper introduces a new TR-UWB system, using frequency-domain components of UWB pulses. This is achieved by separating converted frequency-components into real and imaginary parts, and both parts are correlated and effectively combined. We make an analysis that the new scheme improves performance compared with a conventional by complex correlation computing. The simulation results confirmed that the proposed scheme has better performance than existing system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.3
• /
• pp.289-293
• /
• 2013

In the noncoherent methods for UWB-IR (ultra-wideband impulse radio), block coded modulation (BCM) is better than the transmitted reference (TR) systems in terms of the energy efficiency and data rate. However, even BCM suffers from the performance degradation in the presence of strong inter-frame interference and inter symbol interference. We propose the transmitted reference based on the BCM (TR-BCM) which is the hybrid system of TR and BCM. Performance evaluation shows that the performance of TR-BCM is better than that of BCM in the high SNR range.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.1
• /
• pp.1-6
• /
• 2012

In this paper, the performance comparison of the TR-UWB System using Wavelet Pulse, DPSS pulse, and second Gaussian pulse in multi-user environment is analyzed. The data signal and the reference signal is sent with some time intervals in TR-UWB system. At this time the two signals are through the same channel. In the receiver the reference signal is used as a template. This advantage results in demodulation without channel estimation and low complexity of it. However the conventional TR-UWB system based on a Gaussian signal in a multi-user environment has the disadvantage of poor performance due to the interferences between the users. To overcome this disadvantage, DPSS (Discrete Prolate Shperoidal Sequence) is used to reduce the interferences between the users. We propose the system with multiresolution function of orthogonal wavelet reducing the interferences, which has a better performance in multi-user environment when they are sent in transmission side.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.2
• /
• pp.253-260
• /
• 2009

This paper, mathematically analyzes the performance of newly proposed TR-UWB system which the frequency components of a UWB pulse were processed so that the system could be implemented with ADCs of a few MHz sampling rate, and presents the comparison with an existing frequency-domain based TR-UWB system. The comparison is mainly based on the SNR ratio which depends on the mean and the variance of the frequency components. We also shows that the simulation results to support the theoretical analysis where the comparison is made under the IEEE 802.15.3a channel model as well as AWGN channel.

• Journal of Communications and Networks
• /
• v.14 no.5
• /
• pp.518-523
• /
• 2012

This paper presents new coherent and non-coherent detection methods for the IEEE 802.15.4a low-rate ultra-wideband physical layer with forward error correction (FEC) coding techniques. The coherent detection method involving channel estimation is based on the correlation characteristics of the preamble signal. A coherent receiver uses novel iterated selective-rake (IT-SRAKE) to detect 2-bit data in a non-line-of-sight channel. The non-coherent detection method that does not involve channel estimation employs a 2-bit data detection scheme using modified transmitted reference pulse cluster (M-TRPC) methods. To compare the two schemes, we have designed an IT-SRAKE receiver and a MTRPC receiver using an IEEE 802.15.4a physical layer. Simulation results show the performance of IT-SRAKE is better than that of the M-TRPC by 3-9 dB.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7582-7588
• /
• 2015

Noncoherent receivers are favored for block-code-modulated ultrawideband impulse radio (UWB-IR) systems because of their low implementation complexity compared with coherent rake receivers. However, existing noncoherent schemes, such as transmitted reference (TR) systems and averaged differential receivers (ADR), suffer from performance degradation and energy efficiency loss. Codeword matching and signal aggregation (CMSA) is a low complexity noncoherent receiver for UWB-IR. As the frame/symbol duration is shortened to boost data rate, interframe interference (IFI) or intersymbol interference (ISI) occurs and degrades the detection performance of CMSA. In this paper, block coded correlator which consists of the delay components and the reference signal is proposed to improve the performance of the receiver. Simulation results show that the proposed system leads to the better performance compared to the conventional CMSA receiver.