ISSN : 1796-2056
Volume : 1    Issue : 1    Date : May 2006

Throughput and Delay Analysis of Unslotted IEEE 802.15.4
Benoît Latré, Pieter De Mil, Ingrid Moerman, Bart Dhoedt, Piet Demeester and Niek Van Dierdonck
Page(s): 20-28
Full Text:
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The IEEE 802.15.4 standard is designed as a low power and low data rate protocol offering high
reliability. It defines a beaconed and unbeaconed version. In this work, we analyze the maximum
throughput and minimum delay of the unbeaconed or unslotted version of the protocol. First, the
most important features are described. Then the exact formula for the throughput and delay of a
direct transmission between one sender and one receiver is given. This is done for the different
frequency ranges and address structures used in IEEE 802.15.4. The analysis is limited to the
unslotted version as this one experiences the lowest overhead. It is shown that the maximum
throughput depends on the packet size. In the 2.4 GHz band, a bandwidth efficiency of 64.9% is
reached when the maximum packet size is used. Further we describe the influence of the back off
interval. A significant gain is found when the backs off parameters are altered. We have measured
the throughput experimentally in order to compare the theoretical analysis with real-life examples.

Index Terms
IEEE 802.15.4, multiple access control, performance, throughput