A Survey on Bluetooth 5.0 for Internet of Things

Abstract

The most common challenge faced in IoT large-scale deployments is to enable a wide range of use cases in applications. There are numerous communication technologies such as 4G, WiFi, WPAN, and the latest technology 5G. But now the Bluetooth Special Interest Group (SIG) has released Bluetooth 5.0 and claims to be for IoT specifically, by enhancing all the features of Bluetooth 4.2. Further, three relevant queries such as what is better about Bluetooth 5.0, why does it matters, and how it affects the IoT industry and its applications. With this context, a survey can be made on why Bluetooth 5.0 would be ideal for IoT applications, how Bluetooth 5.0-IoT interact with each other, is Bluetooth 5 a valid technology candidate for implementation of Internet of Things applications, provided the security threats of Bluetooth.

Full text

A Survey on Bluetooth 5.0 for Internet of Things
Jathin Sreenivas
Faculty of Computer Science and Engineering
Frankfurt University of Applied Sciences
Frankfurt, Germany
Jathin.Sreenivas@stud.fra-uas.de
Abstract—The most common challenge faced in IoT large-scale
deployments is to enable a wide range of use cases in applications.
There are a numerous number of communication technologies
such as 4G, WiFi, WPAN, and the latest technology 5G. But
now the Bluetooth Special Interest Group (SIG) has released
Bluetooth 5.0 and claims to be for IoT specifically, by enhancing
all the features of Bluetooth 4.2. Further, three relevant queries
such as what is better about Bluetooth 5.0, why does it matter,
and how it affects the IoT industry and its applications. With
this context, a survey can be made on why Bluetooth 5.0 would
be ideal for IoT applications, how Bluetooth 5.0 - IoT interact
with each other, is Bluetooth 5 a valid technology candidate for
implementation of Internet of Things applications, provided the
security threats of Bluetooth.
I. INTRODUCTION
Bluetooth is a technology that was developed more than 20
years ago. The first version of Bluetooth came up in 1994
when it was just used as a form of data transmission, in
the current era this technology is one of the pillars of the
Internet of Things (IoT). In the past years, the Internet of
Things (IoT) has seen major improvements in the number of
deployments, sensors, automation, and smart devices. IoT are
being researched extensively for a wide range of application
areas, such as private and commercial, industrial and logistic,
or public sectors. In such areas, communication technology is
considered accurately as there are varying requirements. For
IoT use cases, they require a higher communication range,
more speed, and large messaging capacity. Bluetooth 5.0
promises all these features and are has been introduced for
IoT purpose, due to which the number of IoT application has
significantly increased and reached to smart factories, smart
home, and buildings as shown in Figure 1. The term Internet
of Things (IoT) was first used by Kevin Ashton in 1999 in
the context of supply chain management. In the current days,
IoT areas include covering a wide range of applications like
healthcare, transport, and other utilities, etc. IoT vision where
anything in the physical world can be digitally represented
and connected together for communication. The interaction
with sensors, actuators, wireless connectivity, people, and
smart objects is creating a significant improvement in IoT for
intelligent devices.
II. BL UE TOOTH EVO LU TI ON
In the evolution of Bluetooth as illustrated in Figure 2,
the first generation of Bluetooth started with providing the
Basic Rate(BR) for basic functionalities. The next generations
Fig. 1. Expansion of Bluetooth for the Internet of Things [6]
that came along added new features or improved the existing
performance. In Bluetooth 2.x and 3.x, Enhanced Data Rate
(EDR) and High Speed (HS) was introduced to further im-
prove the performance. In generation 4.x Bluetooth Low En-
ergy(BLE) was introduced for applications of Bluetooth which
required low power. And the Bluetooth 5.x has improved
the performance of Bluetooth 4.x significantly. Bluetooth 5.0
achieves
Fig. 2. Bluetooth Evolution [9]
A. Improvements of Bluetooth 5.0 over Bluetooth 4.2
1) Larger Advertising - Bluetooth 5.0 has a major increase
in its messaging capacity, the capacity that can be
transferred is 8 times the capacity of what Bluetooth
4.2 achieves.
2) Increased Range - The transmission range of Bluetooth
5.0 is increased by 4 times the range of Bluetooth 4.2.
With this increasing range, IoT devices can be extended
far away beyond the walls of a typical home.
3) Improved Speed - Bluetooth 5.0 achieves two times the
transmission speed of Bluetooth 4.2.

4) Stronger Robustness - Bluetooth 5.0 establishes much
more stable connections.
5) Mesh Topology - With the mesh topology in Bluetooth
5.0, now Bluetooth can be deployed massively in many
variety topologies.
All of the above points certainly prove that Bluetooth 5.0 is
enhanced significantly. These enhancements make it possible
for Bluetooth to now transfer information much faster, further
by establishing a much more stable connection with a lot more
content. For all these reasons Bluetooth 5.0 is an important
technology for the IoT area. The Bluetooth mesh is not
restricted to just Bluetooth 5.0, Bluetooth 4.0 and above are
supported as well. The network structure has been improved
using the mesh structure, making it possible for a group of
devices to connect rather than just an end-to-end connection.
Bluetooth 5.0 will transform the IoT experience by making it
simple, seamless, precise, and accurate.
III. BLU ETOOT H5-IOT ARCHITECTURE
The architecture of Bluetooth 5 IoT can be divided into six
layers.
1) The hardware Layer - This is the bottom layer compris-
ing the hardware components of IoT, such as sensors
or sensors in smartphones which includes weather sen-
sors, environment sensors, home appliances, and other
physical components. The hardware layer covers up
abstraction to leverage information about its periphery
to the above layer the microcontroller layer.
2) Microcontroller Layer - This layer comprises of the
microcontrollers that are required for automatically con-
trolled devices such as office machines, home appli-
ances, and other embedded systems. Few instances of
what layer comprises of are The Raspberry Pi, AT Mega,
Edison, etc.
3) Bluetooth Connectivity Layer -This layer contains the
wireless standard for exchange, Bluetooth which uses
a variety of protocols. The Bluetooth stack is divided
into two segments. Firstly, the Controller - the controller
is implemented in low-cost silicon devices which con-
tains a time-critical radio interface that is the Bluetooth
radio and a microprocessor. The second segment is
the Host which deals with high-level data, the host
is implemented as a package on top of an operating
system or a part of an operating system itself. For EDR
devices such as Bluetooth earphones, both the host and
the controller are present on the same microprocessor
which reduces the production costs. These devices are
known as hostless systems. However, the host stack also
comprises the protocol for communication between the
host and the controller. Host Controller Interface (HCI)
is a pseudo protocol for standardized communication
between the two stacks. Link Manager Protocol (LMP)
is used to control the connections between the devices,
which include creation, modification, and releasing log-
ical transports or logical links. As well as, to query any
device capabilities and power control. The final protocol
that is the Link Control Protocol (LC) communicates
the flow control, acknowledgment, and retransmission
requests. This protocol is embedded in the header of the
Link Manager protocol.
4) Connectivity Layer - There are two pathways that can be
taken in this layer, Internet Connectivity or Smart Phone
OS. Internet Connectivity is the central part of the whole
stack. IoT specific communication protocols are added
here for energy efficiency, resource constraints, and
lightweight information processing. MQTT, CoAP, IPv6,
UDP, AMQP, LLAP, XMPP, and DDS protocols perform
the following tasks: publish/subscribe messaging, multi-
cast support, real-time messaging, packet-switched net-
working, message queue for middleware, lightweight lo-
cal automation, and direct addressing publish/subscribe
based communication for real-time embedded systems.
The other pathway is the Smart Phone OS: The Wireless
Personal Area Network (WPAN) technology which is
designed for application in health care, fitness, security,
and home automation. Current Mobile devices are al-
ways released with hardware and software support for
Bluetooth. There are already Bluetooth Profiles present
in mobile devices, such as the Blood Pressure Profile
(BLP), and many other Fitness profiles.
5) Infrastructure Layer - The infrastructure layer is the most
valuable layer of all. This layer comprises of four differ-
ent compositions of 1. IoT business cloud services 2. Big
Data Services, and 3. Bluetooth Host API/protocol. The
IoT Business Cloud - an abstraction for business-specific
services. Various business transactions and activities are
served here by SaaS, PaaS, and IaaS cloud solutions.
This modular architecture, as well as packet business
APIs, eases the performance of any business-related
operations. Parallelly also performs resource definition,
abstraction, orchestration, and optimization of its exter-
nal ecosystem. These business clouds reduce the organi-
zation’s overhead of operational activities by providing a
common layered approach with necessary supports pro-
vided. The Bluetooth Host API/Protocol - The host and
controller stacks is divided into various subcategories.
The General Access Profile (GAP) defines the topology
being used by the Bluetooth network stack. The one-to-
one, one-to-many, or many-to-many mechanisms which
are means to connect to the other devices fall under the
mechanism of GAP. During a one-to-one connection,
there should be an explicit connection and here hand-
shake is required to transfer data. The Generic Attribute
Profile (GATT) describes the detailed description of the
transfer attributes once the devices are connected. The
Object Exchange (OBEX) is a communication protocol
that facilitates the exchange of binary objects between
devices. For example, file transfers require simple data
exchange. The OBEX is bound to Radio Frequency
Communication (RFCOMM), which is a set of transport
protocol which is commonly used for its widespread
support and publicly available API on most operating

systems. The Low energy attribute protocol is adapted
for BLE since this protocol allows the client to read and
write certain attributes with a lot more ease. The Big
Data Services, these services make it possible for Big
Data and IoT to work in conjunction. These services can
be used for providing optimizations, statistical analysis,
predictions, etc. By using these services, the network
disks and computer power are impacted. The stack for
big data processing must be done in consideration of the
influx of data that IoT will deliver.
6) Application Layer - This layer is designed to disseminate
the user experience via the software in applications that
are performed over Bluetooth Connectivity. Bluetooth
5.0 with IoT can help solving numerous problems in
fields such as health care, agriculture, sensors in smart
phones, watches, home automation and many more.
Fig. 3. Bluetooth-IoT (BTIoT-5) Architecture [5]
IV. APP LI CATION SCEN AR IO S
Due to all the enhancements to Bluetooth, Bluetooth has a
significant influence in the IoT area. Normally Bluetooth is
used between two devices and broadcasting, which are the
one-to-one and one-to-many applications. With the support
of Mesh topology, now the application can use Bluetooth in
form of many-to-many topology. The effects on the existing
applications by Bluetooth 5.0 are
A. One-to-One: Paired Devices
This is the most known form of Bluetooth communication,
which is being experienced from the first version of Bluetooth.
This form of topology can be seen in all smartphones, wear-
able devices such as wireless earphones, smartwatches, etc.
The typical Bluetooth mode used in these applications is the
BLE or EDR. For applications using BLE such as IoT devices,
smartwatches, Bluetooth 5.0 can be enjoyed as the data rate
is doubled and range-extended, and the time required is cut
down by half. Therefore needing a very less active time for the
same amount of work, which leads to increased battery life.
For the EDR applications such as wireless headphones where
data that needs to be transferred is a lot more, the Bluetooth
5.0 can now transfer the same data for even more further range
with clearer data. Therefore applications that use one-to-one
communication now can send data in a faster way for a longer
range while keeping the performance quality uninfluenced and
also getting a much more stable connection.
B. One-to-Many: Proximity Beacons
A classic example of a one-to-many topology using Blue-
tooth is the beacon-based proximity. These devices continu-
ously broadcast their IDs and information to all its neighbors.
Any devices that are based on the distance and the angle
can collect these IDs and information. Beacons also can carry
large advertising capacity which enables them to carry detailed
information along with its IDs. Now using Bluetooth 5.0
the same process can be done more efficiently. And also
an added advantage of the location feature in Bluetooth 5.0,
beacon devices can provide various context-rich location based
services.
C. Many-to-Many: Meshed Objects
The main feature of Bluetooth 5.0, which allows many-
to-many devices communication. Smart homes/offices and
industrial controls make a huge profit using the Mesh topology
of Bluetooth. In Smart Homes/offices - Smart home appliances
serve the users seamlessly and intelligently. These devices
require a reliable strong connection among IoT devices within
and across rooms. The data that is being transferred ranges
from kilobytes to megabytes. And for certain appliances, they
need to operate on low power. However, Bluetooth was not
the first preference for these applications. Due to the reason
the star topology of Bluetooth, Bluetooth cannot cover a
conference room when there are more than seven applications.
And creates a lot of complexity. Now with Bluetooth Mesh,
Bluetooth has finally had an edge to used in these appliances
as well. Bluetooth is now a competitive player. The ZigBee is
considered ideal for home automation, but Bluetooth may take
over for the reason being Bluetooth is available in all laptops,
mobile phones, and easy for a user to control and manage the
home offices on their smart devices using Bluetooth.
Fig. 4. Three examples of three kinds of topologies of Bluetooth [9]

V. SECURITY AND RELIABILITY TH RE ATS IN BL UE TOOTH
Bluetooth devices are exposed to malicious intervention
during the pairing process with another Bluetooth device, this
is due to the flaw in the link key establishment protocol,
which is required for pairing the device. Encryption in the
process of pairing is optional and created at the end of the
pairing process, meaning that attacks can be performed well
before pairing is complete. Bluetooth transmissions can be
deliberately jammed, denied, intercepted, and manipulated.
False information can be passed to the devices by malicious
users. Security and Reliability threats in Bluetooth can be
classified into three categories:
•Disclosure threat: There can be an eavesdropper in be-
tween the source and the target, and the eavesdropper
is not authorized for the information which is being
transferred.
•Integrity threat: The information that is being transferred
can be deliberately manipulated.
•Denial of Service (DoS) threat: The users can be blocked
from gaining access to a service by making it either
unavailable or severely limiting its availability to an
authorized user.
These weaknesses are the flaws in the link key establishment
protocol which is required for devices to pair as session
encryption is not mandatory. Attacks can occur even before the
pairing completes. A summary of the attacks that can occur
on a Bluetooth network before and after the pairing process
is summarized in Table I.
VI. CONCLUSION
Bluetooth has been in the industry for over two decades
and in this time there is a significant improvement and the
Bluetooth market has continued to expand at an exponential
rate. The evolution of Bluetooth, wherein each version has
bought many improvements and new features. The Bluetooth
5.0 aims at addressing the requirements of the IoT industry.
The Bluetooth IoT architecture makes a strong impact on
how IoT end users can be benefited from using Bluetooth.
Bluetooth has officially come into the battle with its other com-
petitors of communication technology of the IoT industry. It
can be concluded that Bluetooth has made a strong competitor
for the communication technology for the IoT applications and
provides complete solutions for meeting the communication
demands of the IoT industry.
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TABLE I
LIS T OF BLU ETO OTH ATTAC KS . [4]
Type of issue Description of the issue
Attacks Prior to Pairing
PIN cracking The attacker uses a brute force algorithm to identify
the PIN. After cracking the pin, the attacker can
pair with the target device and access information
illegally.
BlueJacking Attacker makes uses of the Bluetooth technology
to send unauthorized messages to Bluetooth enabled
device.
Man-In-The-
Middle
Attacker acts as a legitimate user to establish Blue-
tooth connections to both victims’ devices and to
initiate the IO phase.
BlueSnarfing Attacker hacks the node in order to access devices
files, documents, etc.
MAC spoofing Attackers could impersonate an alternative client and
end connections or modify data during transmission
BlueBugging The intruder gets illegal access to a device and can
then implement unauthorized actions such as making
phone calls etc.
BlueBorne This attack allows an attacker to exploit some inse-
cure implementations of Bluetooth.
Fuzzing This intrusion involves sending malicious data to a
device’s Bluetooth radio and observes how the device
reacts.
BluePrinting A method to remotely extract information from Blue-
tooth enabled devices.
Attacks after Pairing
Backdoor This attack involves establishing a trust relationship
through pairing but ensuring that it no longer appears
on the target’s device.
Denial of Service
(DoS)
In this attack, the attacker prevents valid users from
accessing the service by sending a large number of
messages to the Bluetooth device.
Worm The Cabir worm is a malicious software that uses
Bluetooth technology to search for available Blue-
tooth devices and send itself to them.
Bluesmack This attack is the Bluetooth equivalent of the Ping-
of-Death DoS attack
MultiBlue A MultiBlue dongle, a Bluetooth capable 4 GB drive,
is utilized to take control of the target device.
BD ADDR The attack occurs when a bug is kept within coverage
area of a Bluetooth device. The bug duplicates the
BD ADDR of the target device.
Reflection/Relay An intruder need not be aware of any confidential
data as only relays sensitive data from one node to
the other in the authentication phase.
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