Now showing items 1-7 of 7

  • Bayesian compressive sensing for ultra-wideband channel models 

    Authors:Ozgor, Mehmet; Erküçük, Serhat; Cirpan, Hakan Ali
    Publisher and Date:(IEEE, 2012)
    Considering the sparse structure of ultra-wideband (UWB) channels compressive sensing (CS) is suitable for UWB channel estimation. Among various implementations of CS the inclusion of Bayesian framework has shown potential to improve signal recovery as statistical information related to signal parameters is considered. In this paper we study the channel estimation performance of Bayesian CS (BCS) for various UWB channel models and noise conditions. Specifically we investigate the effects of (i) ...

  • Code shift keying impulse modulation for UWB communications 

    In this paper the system performance of M-ary code shift keying (MCSK) impulse modulation is studied in detail and compared to M-ary pulse position modulation (MPPM) under single- and multi-user scenarios. For that bounds on the semi-analytic symbol-error rate (SER) expressions are derived and simulation studies are conducted. When practical implementations of MCSK and MPPM are considered it is shown that MCSK can provide about 2 dB performance gain over MPPM as it reduces the effects of multipath ...

  • Detection of interdependent primary systems using wideband cognitive radios 

    Cognitive radios (CRs) may be sharing multiple frequency bands with primary systems if the CR is a wideband or an ultra wideband (UWB) system. In that case the CR should ensure all the coexisting primary systems in these bands are detected before it can start data transmission. In this work we study the primary system detection performance of a wideband CR assuming that there are multiple coexisting primary systems and that these primary systems may be jointly active. Accordingly we consider the ...

  • Detection of Multiple Primary Systems Using DAA UWB-IRs 

    Authors:Erküçük, Serhat; Lampe, Lutz; Schober, Robert
    Publisher and Date:(IEEE, 2009)
    Underlay ultra wideband (UWB) systems have to be able to detect the presence of primary systems operating in the same band for detect-and-avoid (DAA) operation. In this paper the performances of joint and independent detection of multiple primary systems are investigated assuming that the primary systems are potentially dependent (e.g. frequency division duplex uplink-downlink communications). Joint detection is performed based on generating the maximum a posteriori (MAP) decision variables at the ...

  • Joint Detection of Primary Systems Using UWB Impulse Radios 

    Regulation in Europe and Japan requires the implementation of detect-and-avoid (DAA) techniques in some bands for the coexistence of licensed primary systems and secondary ultra wideband (UWB) systems. In a typical coexistence scenario a primary system may have potentially interdependent uplink-downlink communication channels (e. g. simultaneous uplink-downlink communications in a frequency division duplex system) overlapping with the frequency band of a UWB system. If such interdependencies of ...

  • Performance of IEEE 802.15.4a Systems in the Presence of Narrowband Interference 

    The regulatory agencies in Europe and Japan require the implementation of avoidance techniques in some bands to reduce interference to licensed systems. Accordingly ultra-wideband impulse radio (UWB-IR) based Wireless Personal Area Network (WPAN) standard IEEE 802.15.4a has suggested using linear combination of pulses to reduce interference to coexisting primary systems. In this paper we consider the implementation of linear combination of pulses for a peaceful coexistence and assess the UWB-IR ...

  • The Effect of Channel Models on Compressed Sensing Based UWB Channel Estimation 

    Authors:Başaran, Mehmet; Erküçük, Serhat; Cirpan, Hakan Ali
    Publisher and Date:(IEEE, 2011)
    Ultra-wideband (UWB) multipath channels are assumed to have a sparse structure as the received consecutive pulses arrive with a considerable time delay and can be resolved individually at the receiver. Due to this sparse structure there has been a significant amount of interest in applying the compressive sensing (CS) theory to UWB channel estimation. There are various implementations of the CS theory for the UWB channel estimation based on the assumption that the UWB channels are sparse. However ...