• Journal of Communications and Networks
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• v.9 no.3
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• pp.330-341
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• 2007

This work analyzes the performance of the parallel packet switch (PPS) with a sliding window (SW) method. The PPS involves numerous packet switches that operate independently and in parallel. The conventional PPS dispatch algorithm adopts a round robin (RR) method. The class of PPS is characterized by deployment of parallel low-speed switches whose all memory buffers run more slowly than the external line rate. In this work, a novel SW packet switching method for PPS, called SW-PPS, is proposed. The SW-PPS employs memory space more effectively than the existing PPS using RR algorithm. Under identical Bernoulli and bursty data traffic, the SW-PPS provided significantly improved performance when compared to PPS with RR method. Moreover, this investigation presents a novel mathematical analytical model to evaluate the performance of the PPS using RR and SW method. Under various operating conditions, our proposed model and analysis successfully exhibit these performance characteristics including throughput, cell delay, and cell drop rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.138-144
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• 2009

This paper proposes an efficient scheme to estimate the channel parameters such as channel gain and delay for the IEEE802.15.4a LR-UWB systems. Sliding window (SW) method is generally used for the channel estimation of LR-UWB systems, which extracts the channel parameters by performing the cross-correlation with the repeatedly transmitted signal. However, the SW method experiences the severe performance degradation because the cross-correlation is performed just once for the received signal. In this paper, we propose a novel channel estimation scheme, which can achieve a great performance gain by performing the cross-correlation repeatedly with the repeated receive signal. In order to verify the performance gain of the proposed scheme, we performed the intensive simulation with the Saleh-Valenzuela channel model. Simulation results show that the proposed scheme has a performance improvement of 4dB compared to the conventional SW channel estimation scheme.