The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform

Xiaodai Dong - One of the best experts on this subject based on the ideXlab platform.

  • Integration Interval determination and decision threshold optimization for improved TRPC-UWB communication systems
    China Communications, 2017
    Co-Authors: Zhonghua Liang, Xiaodai Dong, Junshan Zang, Xiaojun Yang, Huansheng Song
    Abstract:

    Integration Interval and decision threshold issues were investigated for improved transmitted reference pulse cluster (iTRPC-) ultra-wideband (UWB) systems. Our analysis shows that the bit error rate (BER) performance of iTRPC-UWB systems can be significantly improved via Integration Interval determination (IID) and decision threshold optimization. For this purpose, two modifications can be made at the autocorrelation receiver as follows. Firstly, the IID processing is performed for autocorrelation operation to capture multi-path energy as much as possible. Secondly, adaptive decision threshold (ADT) instead of zero decision threshold (ZDT), is used as estimated optimal decision threshold for symbol detection. Performance of iTRPC-UWB systems using IID and ADT was evaluated in realistic IEEE 802.15.4a UWB channel models and the simulation results demonstrated our theoretical analysis.

  • Integration Interval Determination Algorithms for BER Minimization in UWB Transmitted Reference Pulse Cluster Systems
    IEEE Transactions on Wireless Communications, 2010
    Co-Authors: Xiaodai Dong, Zhonghua Liang
    Abstract:

    A recently proposed transmitted reference pulse cluster (TRPC) structure contains compactly spaced reference and data pulses, and enables a low complexity, robust and practical auto-correlation detector to be used at the receiver. Previous research indicated that the Integration Interval of the auto-correlation detector is critical to the performance of TRPC. Therefore, in this paper, three practical data-aided algorithms are introduced to determine the Integration Interval of the TRPC structure: the conventional threshold-crossing concept, the new bit error rate (BER) minimization based approach, and the new hybrid scheme that combines threshold-crossing and the BER minimization concepts. The performances of the three schemes are extensively evaluated by simulation. Results show that, the BER minimization based approach and the hybrid scheme demonstrate around 2 dB performance gain over the threshold-crossing scheme in IEEE 802.15.4a channels. Moreover, the hybrid scheme yields close performance to the BER minimization based scheme with much reduced complexity.

  • VTC Fall - Integration Interval Determination in Transmitted Reference Pulse Cluster Systems for UWB Communications
    2008 IEEE 68th Vehicular Technology Conference, 2008
    Co-Authors: Xiaodai Dong
    Abstract:

    A recently proposed transmitted reference pulse cluster (TRPC) structure contains compactly spaced reference and data pulses, and enables a low complexity, robust and practical auto-correlation detector to be used at the receiver. TRPC has been shown to outperform the conventional transmitted reference and non-coherent pulse position modulation systems in ultra-wideband channels. Previous research indicated that the Integration Interval of the auto-correlation detector is critical to the performance of TRPC. In this paper, practical data-aided algorithms are introduced to determine the Integration Interval of the TRPC structure based on minimizing the system bit error rate. The proposed scheme is compared to the traditional threshold crossing method and demonstrates around 2 dB performance gain in IEEE 802.15.4a channels. A simplified version of the scheme valid for low signal to noise ratios is also presented. The proposed Integration Interval determination method does not require Nyquist rate sampling or analog averaging with symbol long delay lines, and is therefore suitable to practical implementation.

  • Integration Interval Determination in Transmitted Reference Pulse Cluster Systems for UWB Communications
    2008 IEEE 68th Vehicular Technology Conference, 2008
    Co-Authors: Xiaodai Dong
    Abstract:

    A recently proposed transmitted reference pulse cluster (TRPC) structure contains compactly spaced reference and data pulses, and enables a low complexity, robust and practical auto-correlation detector to be used at the receiver. TRPC has been shown to outperform the conventional transmitted reference and non-coherent pulse position modulation systems in ultra-wideband channels. Previous research indicated that the Integration Interval of the auto-correlation detector is critical to the performance of TRPC. In this paper, practical data-aided algorithms are introduced to determine the Integration Interval of the TRPC structure based on minimizing the system bit error rate. The proposed scheme is compared to the traditional threshold crossing method and demonstrates around 2 dB performance gain in IEEE 802.15.4a channels. A simplified version of the scheme valid for low signal to noise ratios is also presented. The proposed Integration Interval determination method does not require Nyquist rate sampling or analog averaging with symbol long delay lines, and is therefore suitable to practical implementation.

Yunfei Chen - One of the best experts on this subject based on the ideXlab platform.

  • New receivers for generalized UWB transmitted reference systems with improved performances
    IEEE Transactions on Wireless Communications, 2010
    Co-Authors: Shuyi Wang, Yunfei Chen, Mark Leeson, Norman C. Beaulieu
    Abstract:

    Generalized ultra-wide bandwidth (UWB) transmitted reference (TR) receivers proposed previously in the literature are improved with respect to the energy allocation in the data packet and the Integration Interval length in the correlator. The improvement refers to a best-effort technique to reduce the receiver bit error rate. Simulation results show that the improvement can provide a performance gain of up to 4.2 dB in signal-to-noise ratio. These results give useful guidance on the design of generalized UWB TR receivers.

  • SINR analysis of BPSK UWB considering IPI and ICI in IEEE channel models and its application
    2009 Fourth International Conference on Communications and Networking in China, 2009
    Co-Authors: Bo Zhao, Yunfei Chen
    Abstract:

    Closed-form expressions for the output signal-to-interference-plus-noise ratio (SINR) in ultra-wideband (UWB) receivers are derived for the IEEE channel models. Unlike results in the literature where only the inter-symbol and/or multiple-access interferences are considered, the derivation in this paper also takes into account inter-path and inter-chip interferences. Effects of the spreading gain and the pulse duration on the output SINR are examined. As an application, the optimal Integration Interval that maximizes the output SINR for a transmitted reference UWB receiver is studied.

  • Average SINR Analysis of DS-BPSK UWB Systems With IPI, ICI, ISI, and MAI and Its Application
    IEEE Transactions on Vehicular Technology, 2009
    Co-Authors: Bo Zhao, Yunfei Chen, Roger J. Green
    Abstract:

    Analytical expressions for the average output signal-to-interference-plus-noise ratio (SINR) of direct-sequence (DS) binary-phase-shift-keying (BPSK) ultra-wideband (UWB) receivers are derived using the IEEE UWB channel models. The derivation takes into account the interpath interference, the interchip interference (IPI), the intersymbol interference (ISI), and the multiple-access interference (MAI). The effects of the spreading gain and the pulse duration on the average output SINR are examined. Using these results, the optimal Integration Interval for a transmitted reference UWB receiver is studied.

Zhonghua Liang - One of the best experts on this subject based on the ideXlab platform.

  • Integration Interval determination and decision threshold optimization for improved TRPC-UWB communication systems
    China Communications, 2017
    Co-Authors: Zhonghua Liang, Xiaodai Dong, Junshan Zang, Xiaojun Yang, Huansheng Song
    Abstract:

    Integration Interval and decision threshold issues were investigated for improved transmitted reference pulse cluster (iTRPC-) ultra-wideband (UWB) systems. Our analysis shows that the bit error rate (BER) performance of iTRPC-UWB systems can be significantly improved via Integration Interval determination (IID) and decision threshold optimization. For this purpose, two modifications can be made at the autocorrelation receiver as follows. Firstly, the IID processing is performed for autocorrelation operation to capture multi-path energy as much as possible. Secondly, adaptive decision threshold (ADT) instead of zero decision threshold (ZDT), is used as estimated optimal decision threshold for symbol detection. Performance of iTRPC-UWB systems using IID and ADT was evaluated in realistic IEEE 802.15.4a UWB channel models and the simulation results demonstrated our theoretical analysis.

  • Integration Interval Determination Algorithms for BER Minimization in UWB Transmitted Reference Pulse Cluster Systems
    IEEE Transactions on Wireless Communications, 2010
    Co-Authors: Xiaodai Dong, Zhonghua Liang
    Abstract:

    A recently proposed transmitted reference pulse cluster (TRPC) structure contains compactly spaced reference and data pulses, and enables a low complexity, robust and practical auto-correlation detector to be used at the receiver. Previous research indicated that the Integration Interval of the auto-correlation detector is critical to the performance of TRPC. Therefore, in this paper, three practical data-aided algorithms are introduced to determine the Integration Interval of the TRPC structure: the conventional threshold-crossing concept, the new bit error rate (BER) minimization based approach, and the new hybrid scheme that combines threshold-crossing and the BER minimization concepts. The performances of the three schemes are extensively evaluated by simulation. Results show that, the BER minimization based approach and the hybrid scheme demonstrate around 2 dB performance gain over the threshold-crossing scheme in IEEE 802.15.4a channels. Moreover, the hybrid scheme yields close performance to the BER minimization based scheme with much reduced complexity.

Mohammad Saquib - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of the Channel Energy Capture in Ultra-Wideband Transmitted Reference Systems
    IEEE Transactions on Communications, 2007
    Co-Authors: Yanxin Na, Mohammad Saquib
    Abstract:

    In this letter, we analyze the expected value of the channel energy capture as a function of the Integration Interval of the correlator in a transmitted reference system. A modified Saleh-Valenzuela channel model is employed. We observe that for the system specifications (such as channel model, data rate, and signal-to-noise ratio) considered here, an Integration Interval that captures approximately 84%-89% of the expected value of the channel energy provides a bit-error probability close to the minimum one.

  • On the channel energy capture in ultra-wide-band transmitted reference systems
    VTC-2005-Fall. 2005 IEEE 62nd Vehicular Technology Conference 2005., 2005
    Co-Authors: Yanxin Na, Mohammad Saquib
    Abstract:

    Dense multipath fading associated with ultra-wide- band (UWB) channel presents technical challenges for reliable communication. To adapt to this radio environment efficiently, we use low complexity transmitted reference spread spectrum system and analyze the average value of the channel energy capture as a function of the Integration Interval of the correlator. In our analysis, we use a measurement based UWB channel model. We find that an Integration Interval that captures approximately 90% of the average value of the channel energy provides a bit error probability (BEP) close to the minimum one. I. INTRODUCTION The ultra-wide-band (UWB) technology has recently drawn significant interest due to its attractive features of low power, low complexity and amazing high data transmission rate. UWB transmission can resolve many paths yielding multipath diversity. Exploitation of this multipath diversity through a Rake receiver requires UWB channel estimation which is a challenging task. An alternative approach to exploit the multipath diversity without estimating channel coefficients explicitly is the transmitted reference (TR) spread spectrum system (1). The original TR system couples the transmission of each information-carrying pulse with a pilot pulse. The received pilot pulse (which is referred to as the reference signal or correlator template) is correlated with the received signal of the information-carrying pulse for demodulating the information symbol. The overhead due to the pilot-pulse transmission in the original TR system was 50%. To overcome this shortcoming, recently, reference (2) introduces a general pilot waveform assisted modulation for TR systems in which transmitter pa- rameters are selected by jointly optimizing channel estimation performance and the information rate. References (3), (4) provide an analytical framework for the TR system based on a sampling expansion approach and use moment generating functions to derive closed-form expressions for the symbol error probability. An important issue in a TR system is that its performance is very sensitive to the length of the Integration Interval of the correlator. Use of a too short Integration Interval captures only a small fraction of the desired signal energy, whereas, that of a too long Integration Interval accumulates unnecessary noise energy at the receiver. Thus, the Integration Interval in a TR system must be carefully selected and the above phenomena was previously observed in (5) and a reference therein. Analysis of (5) is based on the assumption that the correlator template estimate remains a Gaussian vector. In this paper, we analyze the average value of the channel energy capture as a function of the Integration Interval of the correlator. We use a measurement based UWB channel model (6), in which path arrives in a cluster and inter- arrival times of clusters as well as those of paths within a cluster are independent and exponentially distributed random variables. The amplitude of the channel coefficient on each path is a log-normally rather than Rayleigh distributed random variable as suggested by (7), (8). Unlike the received signal energy capture, the channel energy capture does not depend on the transmitter signalling scheme. In addition, the latter is a simpler performance measure than the former in terms of analytical and computational complexities. At the same time, we find that the analysis of the channel energy capture as a function of the Integration Interval provides a fine insight into the effects of the Integration Interval on the bit error probability (BEP). Deriving the closed form expression of the BEP and analyzing it as a function of the Integration Interval for the above channel model are challenging and require further investigation. Our analysis shows that conditioned on the channel, the average value of the channel energy capture increases quickly for small values of the Integration Interval, however, the increase becomes gradual and negligible after some values of the Integration Interval. We show that an Integration Interval that captures approximately 90% of the average value of the channel energy provides a BEP, which is nearly optimum. Use of an Integration Interval close to the optimum one reduces not only the BEP but also the complexity of the integrate-and- dump operation at the correlator compared to the use of the Integration Interval equal to the multipath spread. It should be noted that a UWB system is expected to support high data rate transmission, thus the problem of inter-symbol interference will be inevitable. Unlike most of the existing research works on UWB transceiver design, we present results taking inter- symbol interference into consideration. This work is based on the single user case. However, one can extend our result to the multiuser case (where one transmitter

Norman C. Beaulieu - One of the best experts on this subject based on the ideXlab platform.

  • New receivers for generalized UWB transmitted reference systems with improved performances
    IEEE Transactions on Wireless Communications, 2010
    Co-Authors: Shuyi Wang, Yunfei Chen, Mark Leeson, Norman C. Beaulieu
    Abstract:

    Generalized ultra-wide bandwidth (UWB) transmitted reference (TR) receivers proposed previously in the literature are improved with respect to the energy allocation in the data packet and the Integration Interval length in the correlator. The improvement refers to a best-effort technique to reduce the receiver bit error rate. Simulation results show that the improvement can provide a performance gain of up to 4.2 dB in signal-to-noise ratio. These results give useful guidance on the design of generalized UWB TR receivers.