24-08-2012, 03:05 PM
Comparison of the IEEE 802.11, 802.15.1, 802.15.4 and 802.15.6 wireless standards
[attachment=32642]
Introduction
This paper contains a comparison of some of the wireless standards authored by
the Institute of Electrical and Electronics Engineers (IEEE) [1]. It explain some
of the differences and similarities between the IEEE 802.11, 802.15.1, 802.15.4
and 802.15.6 wireless standards with an emphasis on the physical layer.
2 Wireless standards
The wireless standards that we will investigate in this paper is only a selection
from all the standards available. These explanations are not meant to be
exhaustive.
IEEE 802.11 - WLAN/Wi-Fi
Wireless LAN (WLAN, also known as Wi-Fi) is a set of low tier, terrestrial, network
technologies for data communication. The WLAN standards operates on
the 2.4 GHz and 5 GHz Industrial, Science and Medical (ISM) frequency bands.
It is specified by the IEEE 802.11 standard [2] and it comes in many different
variations like IEEE 802.11a/b/g/n. The application of WLAN has been most
visible in the consumer market where most portable computers support at least
one of the variations.
IEEE 802.15.1 - Bluetooth
The IEEE 802.15.1 standard [3] is the basis for the Bluetooth wireless communication
technology. Bluetooth is a low tier, ad hoc, terrestrial, wireless standard
for short range communication. It is designed for small and low cost devices with
low power consumption. The technology operates with three different classes of
devices: Class 1, class 2 and class 3 where the range is about 100 meters, 10
meters and 1 meter respectively. Wireless LAN operates in the same 2.4 GHz
frequency band as Bluetooth, but the two technologies use different signaling
methods which should prevent interference.
IEEE 802.15.4 - ZigBee
ZigBee is a low tier, ad hoc, terrestrial, wireless standard in some ways similar
to Bluetooth. The IEEE 802.15.4 standard [4] is commonly known as ZigBee,
but ZigBee has some features in addition to those of 802.15.4. It operates in
the 868 MHz, 915 MHz and 2.4 GHz ISM bands.
IEEE 802.15.6
IEEE 802.15.6 is a bit elusive, but some of the available information points to
some kind of wireless Body Area Network (BAN). It is possible that it is meant
to be the WBAN Study Group Medical Body Area Networks (SG-MBAN), but
that group have not yet released any standards. SG-MBAN’s meeting minutes
from their meeting in Montreal, May 2007 [5] indicates that the group name
has not been clarified as one of their members asked if the group title will be
15.5x or 15.6 without getting an answer. This could explain why no standard
has been released and little information about the specification could be found.
According to their meeting minutes from San Fransisco, July 2007 [6] and the
Montreal meeting minutes, the frequency band has not yet been clarified.
A paper by S. Maharj [7] from the University of KwaZulu-Natal is the only
reference of frequency and throughput on 802.15.6 I have been able to find. The
paper says that 802.15.6 will cover the terahertz range and it will use T-rays
which has properties of both light and radio. It also explains that the theoretical
maximum data rate will be in the order of several gigabit. Unfortunately the
information from this paper does not correspond with what I have read from the
meeting minutes of SG-MBAN. However, this is the only concrete information
I could locate.
Modes of operation
Wireless networks can have to distinct modes of operation: Ad hoc and infrastructured.
Infrastructured wireless networks usually have some kind of base
station1 which acts as a central node which connects the wireless terminals.
The base station is usually provided in order to enable access to the Internet,
an intranet or other wireless networks. Most of the time the base stations have
a fixed location, but certain mobile base stations also exist. The disadvantage
over ad hoc networks is that the base station is a central point of failure. If it
stops working none of the wireless terminals can communicate with each other.
Ad hoc networks can be formed “on the fly” without the help of a base station.
Self organization is the key to forming an ad hoc network because initially
there is no central node to talk to. In ad hoc networks the wireless terminals
may communicate directly with each other while terminals in infrastructured
networks has to use the base station to relay their messages.
Frequency, data rate and range
The standards described earlier differ by which frequencies they use and this
affects the data rate and range they can cover. According to Table 2 802.15.6
(BAN) will have a much shorter range than the other technologies, but this
proves to be an advantage. Shorter range communication has lower power requirements,
enables equipment to be smaller and the potential for frequency
reuse is very good. This is good news for BAN since it is designed to be as
unobtrusive as possible by integration into clothing, attached to the body or as
implants.
From the table you can also see that several of the standards operate in the
2.4 GHz band. 802.11g is designed so that it is compatible with 802.11b so that
they can co-exist. However, when a 802.11g base station operates in 802.11b
mode its data rate is reduced to that of 802.11b for all its connected terminals.
802.15.1 also occupies the 2.4 GHz band, but a different signaling method can be
used so that they don’t suffer too badly from interference. Along with these two
standards we also have common household appliances like microwave ovens and
certain wireless phones which might pollute the 2.4 GHz frequency spectrum.
One observation from Table 2 is that 802.11n can have a data rate as high
as 248 Mbps in the same frequency band as the other standards. The major
large in increase in data rate and range is achieved by using technique called
Multiple-Input Multiple-Output (MIMO). MIMO uses more than one sender
and receiver antennas and combines this with special coding techniques in order
to squeeze even more data through the same frequencies.
[attachment=32642]
Introduction
This paper contains a comparison of some of the wireless standards authored by
the Institute of Electrical and Electronics Engineers (IEEE) [1]. It explain some
of the differences and similarities between the IEEE 802.11, 802.15.1, 802.15.4
and 802.15.6 wireless standards with an emphasis on the physical layer.
2 Wireless standards
The wireless standards that we will investigate in this paper is only a selection
from all the standards available. These explanations are not meant to be
exhaustive.
IEEE 802.11 - WLAN/Wi-Fi
Wireless LAN (WLAN, also known as Wi-Fi) is a set of low tier, terrestrial, network
technologies for data communication. The WLAN standards operates on
the 2.4 GHz and 5 GHz Industrial, Science and Medical (ISM) frequency bands.
It is specified by the IEEE 802.11 standard [2] and it comes in many different
variations like IEEE 802.11a/b/g/n. The application of WLAN has been most
visible in the consumer market where most portable computers support at least
one of the variations.
IEEE 802.15.1 - Bluetooth
The IEEE 802.15.1 standard [3] is the basis for the Bluetooth wireless communication
technology. Bluetooth is a low tier, ad hoc, terrestrial, wireless standard
for short range communication. It is designed for small and low cost devices with
low power consumption. The technology operates with three different classes of
devices: Class 1, class 2 and class 3 where the range is about 100 meters, 10
meters and 1 meter respectively. Wireless LAN operates in the same 2.4 GHz
frequency band as Bluetooth, but the two technologies use different signaling
methods which should prevent interference.
IEEE 802.15.4 - ZigBee
ZigBee is a low tier, ad hoc, terrestrial, wireless standard in some ways similar
to Bluetooth. The IEEE 802.15.4 standard [4] is commonly known as ZigBee,
but ZigBee has some features in addition to those of 802.15.4. It operates in
the 868 MHz, 915 MHz and 2.4 GHz ISM bands.
IEEE 802.15.6
IEEE 802.15.6 is a bit elusive, but some of the available information points to
some kind of wireless Body Area Network (BAN). It is possible that it is meant
to be the WBAN Study Group Medical Body Area Networks (SG-MBAN), but
that group have not yet released any standards. SG-MBAN’s meeting minutes
from their meeting in Montreal, May 2007 [5] indicates that the group name
has not been clarified as one of their members asked if the group title will be
15.5x or 15.6 without getting an answer. This could explain why no standard
has been released and little information about the specification could be found.
According to their meeting minutes from San Fransisco, July 2007 [6] and the
Montreal meeting minutes, the frequency band has not yet been clarified.
A paper by S. Maharj [7] from the University of KwaZulu-Natal is the only
reference of frequency and throughput on 802.15.6 I have been able to find. The
paper says that 802.15.6 will cover the terahertz range and it will use T-rays
which has properties of both light and radio. It also explains that the theoretical
maximum data rate will be in the order of several gigabit. Unfortunately the
information from this paper does not correspond with what I have read from the
meeting minutes of SG-MBAN. However, this is the only concrete information
I could locate.
Modes of operation
Wireless networks can have to distinct modes of operation: Ad hoc and infrastructured.
Infrastructured wireless networks usually have some kind of base
station1 which acts as a central node which connects the wireless terminals.
The base station is usually provided in order to enable access to the Internet,
an intranet or other wireless networks. Most of the time the base stations have
a fixed location, but certain mobile base stations also exist. The disadvantage
over ad hoc networks is that the base station is a central point of failure. If it
stops working none of the wireless terminals can communicate with each other.
Ad hoc networks can be formed “on the fly” without the help of a base station.
Self organization is the key to forming an ad hoc network because initially
there is no central node to talk to. In ad hoc networks the wireless terminals
may communicate directly with each other while terminals in infrastructured
networks has to use the base station to relay their messages.
Frequency, data rate and range
The standards described earlier differ by which frequencies they use and this
affects the data rate and range they can cover. According to Table 2 802.15.6
(BAN) will have a much shorter range than the other technologies, but this
proves to be an advantage. Shorter range communication has lower power requirements,
enables equipment to be smaller and the potential for frequency
reuse is very good. This is good news for BAN since it is designed to be as
unobtrusive as possible by integration into clothing, attached to the body or as
implants.
From the table you can also see that several of the standards operate in the
2.4 GHz band. 802.11g is designed so that it is compatible with 802.11b so that
they can co-exist. However, when a 802.11g base station operates in 802.11b
mode its data rate is reduced to that of 802.11b for all its connected terminals.
802.15.1 also occupies the 2.4 GHz band, but a different signaling method can be
used so that they don’t suffer too badly from interference. Along with these two
standards we also have common household appliances like microwave ovens and
certain wireless phones which might pollute the 2.4 GHz frequency spectrum.
One observation from Table 2 is that 802.11n can have a data rate as high
as 248 Mbps in the same frequency band as the other standards. The major
large in increase in data rate and range is achieved by using technique called
Multiple-Input Multiple-Output (MIMO). MIMO uses more than one sender
and receiver antennas and combines this with special coding techniques in order
to squeeze even more data through the same frequencies.