A Comparative Study of Wireless Protocols:
Bluetooth, UWB, ZigBee, and Wi-Fi
Jin-Shyan Lee, Yu-Wei Su, and Chung-Chou Shen
Information & Communications Research Labs
Industrial Technology Research Institute (ITRI)
Hsinchu, Taiwan
jinshyan_lee@itri.org.tw
Abstract— Bluetooth (over IEEE 802.15.1), ultra-wideband
(UWB, over IEEE 802.15.3), ZigBee (over IEEE 802.15.4), and
Wi-Fi (over IEEE 802.11) are four protocol standards for short-
range wireless communications with low power consumption.
From an application point of view, Bluetooth is intended for a
cordless mouse, keyboard, and hands-free headset, UWB is
oriented to high-bandwidth multimedia links, ZigBee is designed
for reliable wirelessly networked monitoring and control
networks, while Wi-Fi is directed at computer-to-computer
connections as an extension or substitution of cabled networks. In
this paper, we provide a study of these popular wireless
communication standards, evaluating their main features and
behaviors in terms of various metrics, including the transmission
time, data coding efficiency, complexity, and power consumption.
It is believed that the comparison presented in this paper would
benefit application engineers in selecting an appropriate protocol.
Index Terms— Wireless protocols, Bluetooth, ultra-wideband
(UWB), ZigBee, Wi-Fi, short-range communications.
I. INTRODUCTION
In the past decades, factory automation has been developed
worldwide into a very attractive research area. It incorporates
different modern disciplines including communication,
information, computer, control, sensor, and actuator
engineering in an integrated way, leading to new solutions,
better performance and complete systems. One of the
increasingly important components in factory automation is the
industrial communication [1]. For interconnection purposes, a
factory automation system can be combined with various
sensors, controllers, and heterogeneous machines using a
common message specification. Many different network types
have been promoted for use on a shop floor, including control
area network (CAN), Process fieldbus (Profibus), Modbus, and
so on. However, how to select a suitable network standard for a
particular application is a critical issue to the industrial
engineers. Lain et al. [2] evaluated the Ethernet (carrier sense
multiple access with collision detection, CSMA/CD bus),
ControlNet (token-passing bus), and DeviceNet (CSMA with
arbitration on message priority, CSMA/AMP bus) for
networked control applications. After a detailed discussion of
the medium access control (MAC) sublayer protocol for each
network, they studied the key parameters of the corresponding
network when used in a control situation, including network
utilization and time delays.
On the other hand, for accessing networks and services
without cables, wireless communications is a fast-growing
technology to provide the flexibility and mobility [3].
Obviously, reducing the cable restriction is one of the benefits
of wireless with respect to cabled devices. Other benefits
include the dynamic network formation, low cost, and easy
deployment. General speaking, the short-range wireless scene
is currently held by four protocols: the Bluetooth, and UWB,
ZigBee, and Wi-Fi, which are corresponding to the IEEE
802.15.1, 802.15.3, 802.15.4, and 802.11a/b/g standards,
respectively. IEEE defines the physical (PHY) and MAC
layers for wireless communications over an action range
around 10-100 meters. For Bluetooth and Wi-Fi, Ferro and
Potorti [4] compared their main features and behaviors in terms
of various metrics, including capacity, network topology,
security, quality of service support, and power consumption. In
[5], Wang et al. compared the MAC of IEEE 802.11e and
IEEE 802.15.3. Their results showed that the throughput
difference between them is quite small. In addition, the power
management of 802.15.3 is easier than that of 802.11e. For
ZigBee and Bluetooth, Baker [6] studied their strengths and
weaknesses for industrial applications, and claimed that
ZigBee over 802.15.4 protocol can meet a wider variety of real
industrial needs than Bluetooth due to its long-term battery
operation, greater useful range, flexibility in a number of
dimensions, and reliability of the mesh networking architecture.
In this paper, after an overview of the mentioned four short-
range wireless protocols, we attempt to make a preliminary
comparison of them and then specifically study their
transmission time, data coding efficiency, protocol complexity,
and power consumption. The rest of this paper is organized as
follows. Section II briefly introduces the wireless protocols
including Bluetooth, UWB, ZigBee, and Wi-Fi. Next, a
comprehensive evaluation of them is described in Section III.
Then, in Section IV, the complexity and power consumption
are compared based on IEEE standards and commercial off-
the-shelf wireless products, respectively. Finally, Section V
concludes this paper.
II. W
IRELESS PROTOCOLS
This section introduces the Bluetooth, UWB, ZigBee, and
Wi-Fi protocols, which corresponds to the IEEE 802.15.1,
The 33rd Annual Conference of the IEEE Industrial Electronics Society (IECON)
Nov. 5-8, 2007, Taipei, Taiwan
1-4244-0783-4/07/$20.00 ©2007 IEEE
46
802.15.3, 802.15.4, and 802.11a/b/g standards, respectively.
The IEEE defines only the PHY and MAC layers in its
standards. For each protocol, separate alliances of companies
worked to develop specifications covering the network,
security and application profile layers so that the commercial
potential of the standards could be realized.
The material presented in this section is widely available in
the literature. Hence, the major goal of this paper is not to
contribute to research in the area of wireless standards, but to
present a comparison of the four main short-range wireless
networks.
A. Bluetooth over IEEE 802.15.1
Bluetooth, also known as the IEEE 802.15.1 standard is
based on a wireless radio system designed for short-range and
cheap devices to replace cables for computer peripherals, such
as mice, keyboards, joysticks, and printers. This range of
applications is known as wireless personal area network
(WPAN). Two connectivity topologies are defined in
Bluetooth: the piconet and scatternet. A piconet is a WPAN
formed by a Bluetooth device serving as a master in the
piconet and one or more Bluetooth devices serving as slaves. A
frequency-hopping channel based on the address of the master
defines each piconet. All devices participating in
communications in a given piconet are synchronized using the
clock of the master. Slaves communicate only with their master
in a point-to-point fashion under the control of the master. The
master’s transmissions may be either point-to-point or point-to-
multipoint. Also, besides in an active mode, a slave device can
be in the parked or standby modes so as to reduce power
consumptions. A scatternet is a collection of operational
Bluetooth piconets overlapping in time and space. Two
piconets can be connected to form a scatternet. A Bluetooth
device may participate in several piconets at the same time,
thus allowing for the possibility that information could flow
beyond the coverage area of the single piconet. A device in a
scatternet could be a slave in several piconets, but master in
only one of them.
B. UWB over IEEE 802.15.3
UWB has recently attracted much attention as an indoor
short-range high-speed wireless communication. [7]. One of
the most exciting characteristics of UWB is that its bandwidth
is over 110 Mbps (up to 480 Mbps) which can satisfy most of
the multimedia applications such as audio and video delivery
in home networking and it can also act as a wireless cable
replacement of high speed serial bus such as USB 2.0 and
IEEE 1394. Following the United States and the Federal
Communications Commission (FCC) frequency allocation for
UWB in February 2002, the Electronic Communications
Committee (ECC TG3) is progressing in the elaboration of a
regulation for the UWB technology in Europe. From an
implementation point of view, several solutions have been
developed in order to use the UWB technology in compliance
with the FCC’s regulatory requirements. Among the existing
PHY solutions, in IEEE 802.15 Task Group 3a (TG3a), multi-
band orthogonal frequency-division multiplexing (MB-OFDM),
a carrier-based system dividing UWB bandwidth to sub-bands,
and direct-sequence UWB (DS-UWB), an impulse-based
system that multiplies an input bit with the spreading code and
transmits the data by modulating the element of the symbol
with a short pulse have been proposed by the WiMedia
Alliance and the UWB Forum, respectively. The TG3a was
established in January 2003 to define an alternative PHY layer
of 802.15.3. However, after three years of a jammed process in
IEEE 802.15.3a, supporters of both proposals, MB-OFDM and
DS-UWB, supported the shut down of the IEEE 802.15.3a task
group without conclusion in January 2006. On the other hand,
IEEE 802.15.3b, the amendment to the 802.15.3 MAC
sublayer has been approved and released in March 2006.
C. ZigBee over IEEE 802.15.4
ZigBee over IEEE 802.15.4, defines specifications for low-
rate WPAN (LR-WPAN) for supporting simple devices that
consume minimal power and typically operate in the personal
operating space (POS) of 10m. ZigBee provides self-organized,
multi-hop, and reliable mesh networking with long battery
lifetime [8-9]. Two different device types can participate in an
LR-WPAN network: a full-function device (FFD) and a
reduced-function device (RFD). The FFD can operate in three
modes serving as a PAN coordinator, a coordinator, or a
device. An FFD can talk to RFDs or other FFDs, while an RFD
can talk only to an FFD. An RFD is intended for applications
that are extremely simple, such as a light switch or a passive
infrared sensor. They do not have the need to send large
amounts of data and may only associate with a single FFD at a
time. Consequently, the RFD can be implemented using
minimal resources and memory capacity. After an FFD is
activated for the first time, it may establish its own network
and become the PAN coordinator. All star networks operate
independently from all other star networks currently in
operation. This is achieved by choosing a PAN identifier,
which is not currently used by any other network within the
radio sphere of influence. Once the PAN identifier is chosen,
the PAN coordinator can allow other devices to join its
network. An RFD may connect to a cluster tree network as a
leave node at the end of a branch, because it may only
associate with one FFD at a time. Any of the FFDs may act as
a coordinator and provide synchronization services to other
devices or other coordinators. Only one of these coordinators
can be the overall PAN coordinator, which may have greater
computational resources than any other device in the PAN.
D. Wi-Fi over IEEE 802.11a/b/g
Wireless fidelity (Wi-Fi) includes IEEE 802.11a/b/g
standards for wireless local area networks (WLAN). It allows
users to surf the Internet at broadband speeds when connected
to an access point (AP) or in ad hoc mode. The IEEE 802.11
architecture consists of several components that interact to
provide a wireless LAN that supports station mobility
transparently to upper layers. The basic cell of an IEEE 802.11
LAN is called a basic service set (BSS), which is a set of
mobile or fixed stations. If a station moves out of its BSS, it
can no longer directly communicate with other members of the
BSS. Based on the BSS, IEEE 802.11 employs the independent
basic service set (IBSS) and extended service set (ESS)
47
network configurations. As shown in Fig. 1, the IBSS
operation is possible when IEEE 802.11 stations are able to
communicate directly without any AP. Because this type of
IEEE 802.11 LAN is often formed without pre-planning, for
only as long as the LAN is needed, this type of operation is
often referred to as an ad hoc network. Instead of existing
independently, a BSS may also form a component of an
extended form of network that is built with multiple BSSs. The
architectural component used to interconnect BSSs is the
distribution system (DS). The DS with APs allow IEEE 802.11
to create an ESS network of arbitrary size and complexity. This
type of operation is often referred to as an infrastructure
network.
III. COMPARATIVE STUDY
Table I summarizes the main differences among the four
protocols. Each protocol is based on an IEEE standard.
Obviously, UWB and Wi-Fi provide a higher data rate, while
Bluetooth and ZigBee give a lower one. In general, the
Bluetooth, UWB, and ZigBee are intended for WPAN
communication (about 10m), while Wi-Fi is oriented to
WLAN (about 100m). However, ZigBee can also reach 100m
in some applications.
FCC power spectral density emission limit for UWB
emitters operating in the UWB band is -41.3 dBm/Mhz. This is
the same limit that applies to unintentional emitters in the
UWB band, the so called Part 15 limit. The nominal
transmission power is 0 dBm for both Bluetooth and ZigBee,
and 20 dBm for Wi-Fi.
Distribution System
APAP
ESS
BSS BSS
IBSS
AP: Access Point
BSS: Basic Service Set
ESS: Extended Service Set
IBSS: Independent BSS
Distribution System
APAP
ESS
BSS BSS
IBSS
AP: Access Point
BSS: Basic Service Set
ESS: Extended Service Set
IBSS: Independent BSS
Fig. 1. IBSS and ESS configurations of Wi-Fi networks.
TABLE I
C
OMPARISON OF THE BLUETOOTH, UWB, ZIGBEE, AND WI-FI PROTOCOLS
* Unapproved draft.
• Acronyms: ASK (amplitude shift keying), GFSK (Gaussian frequency SK), BPSK/QPSK (binary/quardrature phase SK), O-QPSK (offset-QPSK), OFDM
(orthogonal frequency division multiplexing), COFDM (coded OFDM), MB-OFDM (multiband OFDM), M-QAM (M-ary quadrature amplitude modulation), CCK
(complementary code keying), FHSS/DSSS (frequency hopping/direct sequence spread spectrum), BSS/ESS (basic/extended service set), AES (advanced
encryption standard), WEP (wired equivalent privacy), WPA (Wi-Fi protected access), CBC-MAC (cipher block chaining message authentication code), CCM
(CTR with CBC-MAC), CRC (cyclic redundancy check).
32-bit CRC16-bit CRC32-bit CRC16-bit CRC
Data protection
WPA2 (802.11i)CBC-MAC (ext. of CCM)CBC-MAC (CCM)Shared secret
Authentication
RC4 stream cipher
(WEP),
AES block cipher
AES block cipher
(CTR, counter mode)
AES block cipher
(CTR, counter mode)
E0 stream cipher
Encryption
2007> 6500088
Max number of cell nodes
ESSCluster tree, MeshPeer-to-peerScatternet
Extension of the basic cell
BSSStarPiconetPiconet
Basic cell
Dynamic freq. selection,
transmit power control
(802.11h)
Dynamic freq. selectionAdaptive freq. hoppingAdaptive freq. hopping
Coexistence mechanism
DSSS, CCK, OFDMDSSSDS-UWB, MB-OFDMFHSS
Spreading
BPSK, QPSK
COFDM, CCK, M-QAM
BPSK (+ ASK), O-QPSKBPSK, QPSKGFSK
Modulation type
22 MHz0.3/0.6 MHz; 2 MHz500 MHz - 7.5 GHz1 MHz
Channel bandwidth
14 (2.4 GHz)1/10; 16(1-15)79
Number of RF channels
15 - 20 dBm(-25) - 0 dBm-41.3 dBm/MHz0 - 10 dBm
Nominal TX power
100 m10 - 100 m10 m10 m
Nominal range
54 Mb/s250 Kb/s110 Mb/s1 Mb/s
Max signal rate
2.4 GHz; 5 GHz868/915 MHz; 2.4 GHz3.1-10.6 GHz2.4 GHz
Frequency band
802.11a/b/g802.15.4802.15.3a *802.15.1
IEEE spec.
Wi-FiZigBeeUWBBluetoothStandard
* Unapproved draft.
• Acronyms: ASK (amplitude shift keying), GFSK (Gaussian frequency SK), BPSK/QPSK (binary/quardrature phase SK), O-QPSK (offset-QPSK), OFDM
(orthogonal frequency division multiplexing), COFDM (coded OFDM), MB-OFDM (multiband OFDM), M-QAM (M-ary quadrature amplitude modulation), CCK
(complementary code keying), FHSS/DSSS (frequency hopping/direct sequence spread spectrum), BSS/ESS (basic/extended service set), AES (advanced
encryption standard), WEP (wired equivalent privacy), WPA (Wi-Fi protected access), CBC-MAC (cipher block chaining message authentication code), CCM
(CTR with CBC-MAC), CRC (cyclic redundancy check).
32-bit CRC16-bit CRC32-bit CRC16-bit CRC
Data protection
WPA2 (802.11i)CBC-MAC (ext. of CCM)CBC-MAC (CCM)Shared secret
Authentication
RC4 stream cipher
(WEP),
AES block cipher
AES block cipher
(CTR, counter mode)
AES block cipher
(CTR, counter mode)
E0 stream cipher
Encryption
2007> 6500088
Max number of cell nodes
ESSCluster tree, MeshPeer-to-peerScatternet
Extension of the basic cell
BSSStarPiconetPiconet
Basic cell
Dynamic freq. selection,
transmit power control
(802.11h)
Dynamic freq. selectionAdaptive freq. hoppingAdaptive freq. hopping
Coexistence mechanism
DSSS, CCK, OFDMDSSSDS-UWB, MB-OFDMFHSS
Spreading
BPSK, QPSK
COFDM, CCK, M-QAM
BPSK (+ ASK), O-QPSKBPSK, QPSKGFSK
Modulation type
22 MHz0.3/0.6 MHz; 2 MHz500 MHz - 7.5 GHz1 MHz
Channel bandwidth
14 (2.4 GHz)1/10; 16(1-15)79
Number of RF channels
15 - 20 dBm(-25) - 0 dBm-41.3 dBm/MHz0 - 10 dBm
Nominal TX power
100 m10 - 100 m10 m10 m
Nominal range
54 Mb/s250 Kb/s110 Mb/s1 Mb/s
Max signal rate
2.4 GHz; 5 GHz868/915 MHz; 2.4 GHz3.1-10.6 GHz2.4 GHz
Frequency band
802.11a/b/g802.15.4802.15.3a *802.15.1
IEEE spec.
Wi-FiZigBeeUWBBluetoothStandard
48
A. Radio Channels
Bluetooth, ZigBee and Wi-Fi protocols have spread
spectrum techniques in the 2.4 GHz band, which is unlicensed
in most countries and known as the industrial, scientific, and
medical (ISM) band. Bluetooth uses frequency hopping
(FHSS) with 79 channels and 1 MHz bandwidth, while ZigBee
uses direct sequence spread spectrum (DSSS) with 16 channels
and 2 MHz bandwidth. Wi-Fi uses DSSS (802.11),
complementary code keying (CCK, 802.11b), or OFDM
modulation (802.11a/g) with 14 RF channels (11 available in
US, 13 in Europe, and just 1 in Japan) and 22 MHz bandwidth.
UWB uses the 3.1-10.6 GHz, with an unapproved and jammed
802.15.3a standard, of which two spreading techniques, DS-
UWB and MB-OFDM, are available.
B. Coexistence Mechanism
Since Bluetooth, ZigBee and Wi-Fi use the 2.4 GHz band,
the coexistence issue must be dealt with. Basically, Bluetooth
and UWB provide adaptive frequency hopping to avoid
channel collision, while ZigBee and Wi-Fi use dynamic
frequency selection and transmission power control. IEEE
802.15.2 discussed the interference problem of Bluetooth and
Wi-Fi. Also, Sikora and Groza [10] provided quantitative
measurements of the coexistence issue for ZigBee, Bluetooth,
Wi-Fi, and microwave ovens. Shuaib et al. [11] focused on
quantifying potential interferences between Zigbee and IEEE
802.11g by examining the impact on the throughput
performance of IEEE 802.11g and Zigbee devices when co-
existing within a particular environment. Moreover,
Neelakanta and Dighe [12] presented a performance evaluation
of Bluetooth and ZigBee collocated on an industrial floor for
robust factory wireless communications.
C. Network Size
The maximum number of devices belonging to the network’s
building cell is 8 (7 slaves plus one master) for a Bluetooth and
UWB piconet, over 65000 for a ZigBee star network, and 2007
for a structured Wi-Fi BSS. All the protocols have a provision
for more complex network structures built from the respective
basic cells: the scatternet for Bluetooth, peer-to-peer for UWB,
cluster tree or mesh networks for ZigBee, and the ESS for Wi-
Fi.
D. Security
All the four protocols have the encryption and authentication
mechanisms. Bluetooth uses the E0 stream cipher and shared
secret with 16-bit cyclic redundancy check (CRC), while UWB
and ZigBee adopt the advanced encryption standard (AES)
block cipher with counter mode (CTR) and cipher block
chaining message authentication code (CBC-MAC), also
known as CTR with CBC-MAC (CCM), with 32-bit and 16-bit
CRC, respectively.
In 802.11, Wi-Fi uses the RC4 stream cipher for encryption
and the CRC-32 checksum for integrity. However, several
serious weaknesses were identified by cryptanalysts, any wired
equivalent privacy (WEP) key can be cracked with readily
available software in two minutes or less, and thus WEP was
superseded by Wi-Fi protected access 2 (WPA2), i.e. IEEE
802.11i standard, of which the AES block cipher and CCM are
also employed.
E. Transmission Time
The transmission time depends on the data rate, the message
size, and the distance between two nodes. The formula for
transmission time (µs) can be described as:
propbitovhdmaxPlddatadatatx ))/(( TTNNNNT +××+= (1)
where N
data
is the data size, N
maxPld
is the maximum payload
size, N
ovhd
is the overhead size, T
bit
is the bit time, and T
prop
is
the propagation time between any two devices. For simplicity,
the propagation time is negligible in this paper. The typical
parameters of the four wireless protocols used for transmission
time evaluation are listed in Table II. Note that the maximum
data rate 110 Mbit/s of UWB is adopted from an unapproved
802.15.3a standard. As shown in Fig. 2, the transmission time
for the ZigBee is longer than the others because of the lower
data rate (250 Kbit/s), while UWB requires less transmission
time compared with the others. Obviously, the result also
shows the required transmission time is proportional to the data
payload size and disproportional to the maximum data rate.
TABLE II
T
YPICAL SYSTEM PARAMETERS OF THE WIRELESS PROTOCOLS
Standard Blue tooth UWB ZigBee W i-Fi
IEEE Spec. 802.1 5.1 802. 15. 3 802. 15. 4 802.11 a/b/g
Max data rate (Mbit/s) 0.72 110* 0.25 54
Bit time (
μ
s) 1.39 0.009 4 0.0185
Max data payload (bytes) 339 (DH5) 2044 102 2312
Max overhead (bytes) 158/8 42 31 58
Coding efficiency
+
(%)
94.41 97.94 76.52 97.18
* Unapproved 802.15.3a.
+
Whe re the data is 10K bytes .
10
0
10
1
10
2
10
3
10
4
10
0
10
2
10
4
10
6
Data Payload Size (bytes)
Transmission Time (microseconds)
ZigBee
Bluetooth
Wi-Fi
UWB
10
0
10
1
10
2
10
3
10
4
10
0
10
2
10
4
10
6
Data Payload Size (bytes)
Transmission Time (microseconds)
ZigBee
Bluetooth
Wi-Fi
UWB
Fig. 2. Comparison of the transmission time versus the data size.
F. Data Coding Efficiency
In this paper, the data coding efficiency is defined by the
ratio of the data size and the message size (i.e. the total number
of bytes used to transmit the data). The formula for data coding
efficiency (%) can be described as:
49
))/(/( ovhdmaxPlddatadatadata codEff NNNNNP ×+=
(2)
The parameters listed in Table II are also used for the coding
efficiency comparison. Fig. 3 shows the data coding efficiency
of the four wireless networks versus the data size. For small
data sizes (around smaller than 339 bytes), Bluetooth is the
best solution. Also, ZigBee have a good efficiency for data size
smaller than 102 bytes. For large data sizes, Bluetooth, UWB,
and Wi-Fi have much better efficiency of over 94%, as
compared to the 76.52% of ZigBee (where the data is 10K
bytes as listed in Table II). The discontinuities in Fig. 2 and 3
are caused by data fragmentation, i.e. the maximum data
payload, which is 339, 2044, 102, and 2312 bytes for
Bluetooth, UWB, ZigBee, and Wi-Fi, respectively. In a Wi-Fi
infrastructure mode, note that most APs connect to existing
networks with Ethernet, and therefore limit the payload size to
the maximum Ethernet payload size as 1500 bytes. However,
for a general comparison, an ad-hoc mode is assumed and the
2312 bytes is adopted in this paper.
For a wireless sensor network in factory automation systems,
since most data size of industrial monitoring and control are
generally small, (e.g. the temperature data in an environmental
monitoring may required less than 4 bytes only), Bluetooth and
ZigBee protocols may be a good selection (from a data coding
efficiency point of view) in spite of their slow data rate.
10
0
10
1
10
2
10
3
10
4
0
20
40
60
80
100
Data Payload Size (bytes)
Data Coding Efficiency (%)
ZigBee
Bluetooth
Wi-Fi
UWB
10
0
10
1
10
2
10
3
10
4
0
20
40
60
80
100
Data Payload Size (bytes)
Data Coding Efficiency (%)
ZigBee
Bluetooth
Wi-Fi
UWB
Fig. 3. Comparison of the data coding efficiency versus the data size.
In this section, an evaluation of the Bluetooth, UWB, ZigBee,
and Wi-Fi on different aspects is provided. It is important to
notice that several slight differences exist in the available
sources. For example, in the IEEE 802.15.4 standard, the
action range is about 10m, while it is 70-300m in the released
documents from ZigBee Alliance. Thus, this paper intends to
provide information only, since other factors, such as receiver
sensitivity and interference, play a major role in affecting the
performance in realistic implementations.
IV. P
ROTOCOL COMPLEXITY AND POWER CONSUMPTION
A. Protocol Complexity
In this paper, the complexity of each protocol is compared
based on the numbers of primitives and events. Table III shows
the number of primitives and host controller interface (HCI)
events for Bluetooth, and the numbers of MAC/PHY
primitives for UWB, ZigBee, and Wi-Fi protocols. In the
MAC/PHY layers, the Bluetooth primitives include client
service access point (SAP), HCI SAP, synchronous
connection-oriented (SCO) SAP, and logical link control and
adaptation protocol (L2CAP) primitives. As shown in Fig. 4,
the Bluetooth is the most complicated protocol with 188
primitives and events in total. On the other hand, ZigBee is the
simplest one with only 48 primitives defined in 802.15.4. This
total number of primitives is only about one fourth the number
of primitives and events defined in Bluetooth. As compared
with the Bluetooth, UWB, and Wi-Fi, the simplicity makes
ZigBee very suitable for sensor networking applications due to
their limited memory and computational capacity.
TABLE III
N
UMBER OF PRIMITIVES AND EVENTS FOR EACH PROTOCOL
Standard
Bluetooth UWB ZigBee W i-Fi
Standard
IEEE Spec.
802.15.1 802.15.3 802.15.4 802.11a/b/g
IEEE Spec.
Primitives 151 77* 35 32 MAC primitives
HCI events 37 29 13 43 PHY primitives
* Approved 802.15.3b.
0
50
100
150
200
Bluetooth
Num. of Primitives / Events
UWB ZigBee Wi-Fi
PHY prim.
MAC prim.
BT events
BT prim.
0
50
100
150
200
Bluetooth
Num. of Primitives / Events
UWB ZigBee Wi-Fi
PHY prim.
MAC prim.
BT events
BT prim.
PHY prim.
MAC prim.
BT events
BT prim.
Fig. 4. Comparison of the complexity for each protocol.
B. Power Consumption
Bluetooth and ZigBee are intended for portable products,
short ranges, and limited battery power. Consequently, it offers
very low power consumption and, in some cases, will not
measurably affect battery life. UWB is proposed for short-
range and high data rate applications. On the other hand, Wi-Fi
is designed for a longer connection and supports devices with a
substantial power supply. In order to practically compare the
power consumption, four wireless products for which detailed
characteristics are publicly available are briefly presented as an
example, including BlueCore2 [13] from Cambridge Silicon
Radio (CSR), XS110 [14] from Freescale, CC2430 [15] from
Chipcon of Texas Instruments (TI), and CX53111 [16] from
Conexant (previous Intersil’s Prism). The current
consumptions of the transmit (TX) and receive (RX) conditions
for each protocol are shown in Table IV. The data shown are
for particular products, although are broadly representative for
examples of the same type. Fig. 5 indicates the power
consumption in mW unit for each protocol. Obviously, the
50
