| Vol. 4, No. 1, May 2007- Art. 9 |
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| The Aloha access (UWB)2 protocol revisited for IEEE 802.15.4a |
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by
Maria-Gabriella Di Benedetto, Luca De Nardis, Guerino Giancola,
Daniele Domenicali, School of Engineering, University of Rome
La Sapienza
Copyright
Copyright © Università degli Studi di Roma - La
Sapienza, 2007 |
| | | Abstract
The IEEE 802.15.4a Task Group recently proposed Impulse Radio Ultra
Wide Band (IR-UWB) for a physical layer that can provide combined
communication and ranging in low data rate indoor/outdoor networks.
At present, it is therefore particularly relevant to design IEEE
802.15.4a MAC strategies that are appropriately tailored on the
physical layer. Previously, we proposed the Uncoordinated Baseborn
Wireless medium access control for UWB networks (UWB)2, a UWB-tailored
MAC based on the low probability of pulse collision. The (UWB)2
adopted the Aloha principle and enabled location-based network optimization
by providing and storing estimates of distance between nodes.
This paper first revisits the (UWB)2 MAC protocol in view of its
application to IEEE 802.15.4a. The structure of both control and
data MAC protocol data units is defined based on the legacy 802.15.4
MAC in order to allow a seamless support, for both centralized and
distributed network topologies, as defined in the parent standard.
Secondly, this work extends and completes the analysis of (UWB)2
since it takes into account multipath-prone channels. Channel parameters,
for both indoor and outdoor propagation scenarios in Line Of Sight
(LOS) and Non-Line Of Sight (NLOS) conditions, were derived from
the channel model defined within the 802.15.4a channel sub-committee.
Results highlight that the (UWB)2 protocol is robust to multipath,
and provides high throughput and low delay, with performance scaling
gracefully as a function of the number of users and the user bit
rate. Results confirm and support the adoption of (UWB)2 principles
for low data rate UWB communications. |
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