| Summary: | 碩士 === 國立臺北科技大學 === 電機工程系所 === 93 === Though eight data rates have been presented by direct sequence ultra-wideband (DS-UWB) standard to satisfy various requirements, only one fixed data rate can be employed during the whole transmission period because the data rate switching mechanism is not supported yet. Therefore, the DS-UWB system will never achieve maximum data throughput since it cannot adapt the transmitting data rate to the dynamic channel situations. To overcome this difficulty, an adaptive data rate switching scheme based on the statistics of ARQN of the ARQ scheme is proposed to switch the data rates of 110 Mbps, 220 Mbps, 330 Mbps, and 660 Mbps.
A series of simulations is conducted over the UWB channels of CM1, CM2, CM3, and CM4 to explore the through improvement of DS-UWB with stop-and-wait ARQ by using the proposed switching scheme. Since the allowed delay time is not specified in the UWB system yet, the 10 ms delay time threshold is therefore specified to ensure high quality service.
Experimental results indicate that the proposed scheme can effectively switch the data rate by adaptively tracking the channel variations and thus significantly enhances system throughput.
|
|---|
