1-3hit |
In this letter, the bandwidth adaptation of an adaptive IIR multiline enhancer is explored. In addition to the problem of bias cancellation of the main structure, different aspects of the proposed filter such as noise equivalent bandwidth and optimal bandwidth are considered and compared with the half power bandwidth of the adaptive multiline enhancer. Since the center frequency of the multiple sinusoids of the input signal is estimated with no bias, with the assumption that the center frequency of the incoming signal is accurately adapted, the error surface of the algorithm is calculated analytically as a function of the filter bandwidth. Computer simulations are used to compare optimum and adapted bandwidths.
Khodayar SARFARAZ Seyed Ali GHORASHI Mohammad GHAVAMI Hamid AGHVAMI
In this paper the coexistence issue between the DS-UWB systems and Wi-Max/IEEE-802.16 based Fixed Broadband Wireless Access (FBWA) systems has been investigated. The aim is to evaluate the impact that the interference resulting from a realistic UWB hot spot scenario may have on the performance of a FBWA receiver. A mathematical model is developed through which the interference power produced by the UWB hot spot can be calculated. The benchmarks against which the UWB interference is assessed are also developed using the specifications of Wi-Max/IEEE-802.16 systems. Several simulations have been done to both validate the analytical results and calculate the UWB interference. In doing so, the effects of parameters like victim receiver bandwidth, carrier frequency, activity factor, the number of users and the distance from victim receiver in a realistic hot spot scenario have been studied.
Stephane CIOLINO Mohammad GHAVAMI Hamid AGHVAMI
This paper proposes wavelet packets for use in ultra wideband communications. The pulse shapes that are generated are quasi orthogonal and have almost identical time duration. After normalization, an M-ary signaling set can be constructed allowing higher data rate. Finally, the performance of such a system when multipath propagation occurs is investigated by computer simulations. In order to combat multipath fading, a Rake receiver using coherent channel estimation is designed. This channel estimation is carried out using adaptive algorithms such as least-mean square (LMS), normalized least-mean square (NLMS), or recursive least square (RLS) algorithms which adapt the received signal given a reference signal.