In this research, we are going to study about a routing protocol named “Routing Protocol for Low-Power and Lossy Networks” or RPL protocol for replacing old protocol that is applied in B
Literature review
Network structure
Bluetooth Low Energy (BLE) is a wireless communications technology created by the Bluetooth Special Interest Group (SIG) and introduced as part of the Bluetooth 4.0 core specification In contrast with previous Bluetooth versions, BLE is mainly intended for applications involving simple devices (e.g., battery-enabled sensors) that need to infrequently transfer small units of data with remarkably low power consumption Thanks to these characteristics and fuelled by its common support in consumer electronics devices (e.g., smartphones), BLE has become a major communications technology for the Internet of Things (IoT)
Initially, BLE only supported the star network topology, where devices communicate directly with a central hub However, the emergence of competing IoT technologies that support mesh network topologies has prompted the adoption of mesh networks by BLE Mesh networks offer advantages in terms of network robustness and coverage, making them suitable for large-scale IoT deployments where connectivity and reliability are crucial.
This study focuses on developing a method to evaluate the reliability of several mesh networks based on BLE connections, by building a tool to simulate real-time network operations
BLE – Bluetooth Low Energy, sometimes referred to as “Bluetooth Smart”, is a light subset of classic Bluetooth and was introduced as part of the Bluetooth 4.0 core specification While there is some overlap with lineage and was started by Nokia as an in- house project called “Wibree” before adopted by the Bluetooth SIG
BLE is a low-power wireless technology used for connecting devices Since it is a low-power technology, BLE is targeted more towards applications that need to consume less power and they need to run on batteries for longer period of time This technology is not an upgrade to the original Bluetooth, it is rather a new technology that utilizes the
Bluetooth brand but focuses more on IoT applications where small amounts of data are transferred at low speeds BLE operates at 2.4 GHz ISM Band which is the same spectrum as the original Bluetooth or others technology like Wi-Fi or ZigBee Classic Bluetooth cannot communicate directly with the BLE, but some devices support both Bluetooth and BLE and allow them to talk independently
Some applications that make use of BLE technology:
• Home automation like door lock, lighting system…
• Fitness devices in some wearable and tracker, …
• Indoor location technology where GPS may not be feasible
• Medical and personal health devices
The reason why we choose BLE to be the main technology that applied in this research:
• Lower power consumption even comparing to other technologies
• Most of documents related to BLE are freely available
• Lower cost to get the module and chipset, the price even goes down lately
• BLE is existed and utilized in most common phone nowadays, it means we can easily use, share, connect and develop those BLE devices and meshes with the community
• Its range is suitable for the applications in home or small places
1.1.2 Characteristics and operating mechanism of BLE
Two main kinds of devices:
• Central devices: The devices that are capable of handling processing, controlling… in term of Central Processing Unit (CPU) power, memory and battery capacity
• Peripheral devices: The device that is mostly resource constrained in order to save battery
This is an asymmetrical technology and most of the heavy lifting and the processing responsibility is put on the central devices Thus, this allows the peripheral devices to sleep for longer period of time and consume less power
Two modes that a mealy device can operate:
• Advertising mode: The state that the device sends out data for other devices to discover it In this mode, the data sent out is in one direction and comes only from the broadcaster
• Connection mode: This state is when the device is connected to another one In this mode, the data transfer is bi-directional
In order to connect two devices, first the broadcaster has to advertise then allow connection to be established from other devices that discovered it
There are 40 channels that are utilized by the radio They line the range from 2400 MHz to 2480 MHz, separated by 2MHz, center to center
• Primary advertisement channels: The channels that are named 37, 38 and 39
• Secondary advertisement channels: The channels that are named from 0 to 36
• Broadcast oriented: device broadcasting data for others to discover it or allow a connection to be established to that device
• Connection oriented: Devices will be connected to synchronize and exchange data regularly
The Generic Access Profile (GAP) plays a crucial role in Bluetooth technology It governs device discoverability and connection, allowing your device to be visible to other Bluetooth-enabled devices GAP also defines the interaction protocols between devices, ensuring seamless communication and data exchange.
• Broadcaster – Observer: o Broadcaster: The device that sends out advertisements but does not allow a connection to be established with it o Observer: The device that reads those advertisements and looks for other devices but also does not initiate a connection with those advertising devices
• Peripheral – Central: o Peripheral: The device that sends out advertisements and allows other devices to initiate a connection with it o Central: The device that reads those advertisements, looks for other devices and has the ability to initiate a connection with the advertising devices GAP modes:
GAP mode is the state that a device can switch to in order to achieve a certain goal and it can be temporary
• Broadcast: Simply send out advertisements and does not allow other devices to connect with it
• Discoverability: Decide whether it can be discovered or not
• Connectability: Decide whether it can be connected to or not
• Bonding: The state that it is bonded to a device for a secured connection
The packets that are sent out by a broadcaster or device that want to be discovered and then possibly connected to, which is sent out on the three primary advertising channels and repeat at a fixed interval
This is the most important parameter related to advertisements This value defines how often a device sends out advertisement packets During the interval, the device will send out the one advertising packet on each of the primary advertising channels or a subset of these channels The value of the advertising interval ranges between 20 milliseconds and 10.24 seconds, in increment of 625 microseconds
This value stands for the period of time that a device can sleep before waking up again to send out advertising data Since BLE devices have low power-consumption as one of their characteristics, this value affect heavily to its battery, so it is important to choose an appropriate interval
An advertising packet contains of many types of information And in most case, it will include these kinds of information:
• Transmit power – which is usually along with RSSI (Received Signal Strength Indication)
• Server UUIDs (Universally Unique Identifier)
The maximum advertising data capacity has the value of 31 bytes In some situation, that 31-byte capacity is not enough for sending out necessary data, thus we can make scan request to the device to send scan response for more information
A way to establish president date communication that synchronized and allow data exchange between to devices
• The peripheral sending out the advertisement packet that allowing the central to discover it then decide to initiate connection Then connection can now be initiated on the secondary advertisement channels
Routing Protocol Theory
As we mentioned above, BLE mesh’s traditional routing protocol is not suitable the network when want to extend to a large mesh Thus, in this section, we are going to discuss about a protocol that usually applied in Low-Power and Lossy Network such as BLE mesh, which is “Routing Protocol for Low-Power and Lossy Network”, also called as RPL
Before going in the section, there are some definitions that are important in this theory:
• Root: A node which has no outgoing edge
• Up: Edge that is directed towards the root
• Down: Edge that is directed away from the root
• Rank: Number of hopes from the root to the node that is under consideration
• RPL Instance: When a network has one or more DODAGs, each DODAG is an instance
• Directed Acyclic Graph (DAG): A directed graph with no directed cycles This means that from any vertex or point in the graph, we cannot follow an edge or a line back to this same point
• Distance Oriented Directed Acyclic Graphs (DODAG): A special case of DAG, where all nodes are intended to reach a destination
• DODAG ID: The address of a DODAG Each DODAG has an IPv6 ID of 128 bits and it is given to its root only and it stays until the route does not change
• DODAG Version: Each new shape of DODAG is a new version
• Grounded: When DODAG reaches its goal, it is known as grounded “G” is short for “Grounded”
• Floating: When DODAG is not connected or yet to reach its goal, it is known as floating “F” is short for “Floating”
• Parent Node: The node where the arrow is pointing towards
• Child Node: The node where the arrow comes from
• Sub-DODAG: A subtree of a given DODAG
• Storing Node: The node that keep the whole routing table Root node is always the
• Non-Storing Node: The nodes that know only about their parents They cannot restore the routing table
• DODAG Information Solicitation (DIS): A message that a node will send when a node wants to join DODAG The purpose of this message is for the node to know whether if any DODAG exists
• DODAG Information Object (DIO): A multi-casted downward message It contains the information about the parent nodes, sender’s rank and other properties This message can help other nodes to know about the graph and how to join it It also sends the message to other nodes in the DODAG for them to know when the graph changed and what it has changed
• DODAG Advertisement Object (DAO): A message that contains a request sent by the child node to the root node The request is to allow the child node to join in the DODAG
• DAO Acknowledge (DAO-ACK): A response sent by the root or parent to the child node This response contains the answer from the root to the child node’s request
• Consistency Check (CC): Security check, it gives consistency to the DODAG
1.2.2 Reason for choosing Routing Protocol for Low-Power and Lossy Networks protocol in this research
Routing protocols are mechanisms for exchanging routing information between routers to make routing decisions Routing protocols can facilitate effective and efficient communication between computer networks Regardless of the scale of the network, these protocols facilitate the secure delivery of data to its destination These are some popular routing protocols:
• Routing Information Protocol (RIP): This is a protocol based on Distance Vector
Protocol RIP utilizes hop-count as a metric to routing, which means it depends on the number of router that a packet has to go through to determine the path In order to avoid the situation where the infinite loop occurs, RIP will limit the hop-count o the maximum of 16
• Open Shortest Path First (OSPF): This is a protocol based on Link-State Routing
Protocols and is utilized in an area or a network system Each router has the information about all the network then determines the shortest path based on that information OSPF uses the Link-State Advertisement messages (LSA) to transfer and store information into a database named Link-State Database (LSDB) to remain the synchronization between routers
• Interior Gateway Routing Protocol (IGRP): This is a routing protocol based on
Distance Vector Routing Protocols It is developed by Cisco IGRP is a part of routing system within an autonomous system One of the noticeable features of IGRP is the summarization at the network boundary, which optimizes the routing management and minimizes the network traffic The IGRP metric, which includes bandwidth, reliability and load, is calculated in order to determine the best path in the network However, the change in the metric has to be done carefully to avoid the affection to the network stability and routing paths
In this research of Bluetooth Low-Energy (BLE) mesh, the reliability and the optimization in power consumption is the highest priority However, those above protocols
21 are all complicated protocols, which are not suitable for BLE mesh, which originally made for optimizing efficiency and resources Moreover, those protocols are usually designed for utilizing in wired networks or strong wireless networks, meanwhile BLE mesh is usually work in a wireless network and requires the flexibility and good interaction with mobile devices
Due to the properties of BLE mesh, the most suitable protocol to implement in this mesh is the Routing Protocol for Low-Power and Lossy Networks protocol (RPL) The reason why this protocol is chosen in this research is due to the following reasons:
• Power consumption: RPL is designed to work efficiently with the devices that have low energy consumption within BLE network Its routing protocol helps optimizing the energy consumption by using Objective Function for finding the shortest path between devices
• Flexibility: RPL allows BLE mesh to extend in a flexible way and can automatically adapt with the change in the environment or network requirements
• Reliability: RPL provides the self-fixing mechanics when some problems occur by using the mechanics such as DODAG repair or DAO retransmission
• IPv6 and IoT Compatibility: RPL is a part of IPv6 protocol standard, which helps the network to be compatible with other IoT systems, Internet services and provide the global connectivity
RPL is a proactive IPv6 Routing Protocol based on distance vectors and operates on IEEE 802.15.4, optimized for multi-hop, many-to-one communication and one-to-one messages This protocol is specified in Request For Comments document (RFC) 6550 with special application in RFCs 5867, 5826, 5673 and 5548 RPL can support a wide variety of link layers, including those with limitations, with potential losses or that are used in devices with limited resources This protocol can quickly create network routes, share routing knowledge, and adapt the topology in an efficient way
RPL creates a topology which is similar to Distance Oriented Directed Acyclic Graphs (DODAG) Directed Acyclic Graph (DAG) is a directed graph with no directed cycles This means that from any vertex or point in the graph, we cannot follow an edge
22 or a line back to this same point DODAG is a special case of DAG, where each node wants to reach a single destination
Figure 3: An example of a DODAG
Main Features and Advantages of RPL:
Data and Methodology
Sensor Network Structure
In general, BLE consists of 2 main factors: Central devices and Peripheral devices Central devices are usually the devices that have high performance CPUs, large memory and high-capacity battery to deal with high-load operation Meanwhile, Peripheral devices are usually the devices that stay in an energy-constrained mode most of the time
• Central Device: Devices which hold most of the heavy-lifting process in the network, includes: o Transferring requests from users to end devices which directly handling its function In this research, this transferring process is handled by Wi-
Fi Low-Energy (WiLe) technology due to the characteristic of BLE mesh o Determining the appropriate routing path for message packets The routing path chosen is considered to be the most efficient and effective way based on its algorithms o Preventing the errors that occurs during the process when the network is working The errors that have been mentioned above can come from both inner problems during transmitting and outside attacks
• Peripheral Device: Devices that mainly handle their functions, turning off the radio for most of the time to saving energy: o They are designed to maximum the power-consumption efficiency by disabling their radio for most of the time, which also called “sleep” state
32 o Usually take the roles of being end devices in the BLE mesh
In the network of this research, these are the main nodes that are utilized:
• Relay node: The node that forwards its received messages The purpose of this node is to increase the length in reality that a message can go as BLE transmission has a limit in the range Mesh network Protocol Data Unit (PDU) includes a field called Time To Live (TTL) It takes a integer value to limit the number of hop that a message can make across the network
• Low Power Node (LPN): This type of node turns off its radio most of the time to conserve as much energy as possible Devices of this type may be predominantly concerned with sending messages but still have a need to occasionally receive messages
For example, a temperature sensor will send back the message about the temperature once a minute and whenever the temperature goes above or below the threshold that have been set up before However, when sending messages to the sensor, like changing in the threshold, it will not change immediately since its radio is off during the time the message is sent The moment it will adjust the threshold according to the message is when it turns on the radio again This can be the moment it sends the message about changing in the period of one minute This parameter can be set up by user
• Friend Node: This node will receive the messages that user sends to the LPN then hold it till the LPN wakes up to pull the messages from Friend Node back The relationship between LPN and Friend Node is known as friendship This is the key to allow very power constrained nodes which need to receive message can operate properly in a mesh and in an efficient way
• Proxy Node: This node plays the role of message transmitter between smart phone and devices in the network This node exposes a GATT interface which
BLE devices may use to interact with a mesh network A protocol called the Proxy Protocol, intended to be used with a connection-oriented bearer such as GATT is defined GATT devices read and write Proxy Protocol PDUs from within GATT characteristics implemented by the Proxy Node The Proxy Node transforms these PDUs to/from mesh PDUs In summary, Proxy Node allows BLE devices that do not possess a Bluetooth mesh stack to interact with nodes in a mesh network
The following figure shows an example for a basic BLE topology:
Figure 13: Basic BLE Network Topology
In this figure, there are four main types of bearers in the network:
Each node in the mesh can be fill in with multiple types of devices with BLE supported, for example:
• In the position of Relay Node, we can use a switch for each position so that we can control End Device by directly through the switch or in a indirectly way For indirectly way, we can use a phone to send messages to the Proxy Node and then those messages are transferred to those End Devices
• In the position of Friend Node, we can use a device that is designed specifically to receive messages and storing them, or we can integrate that function into a specific device, a switch or a sensor that can detects human motions,…
• In the position of Proxy Node, we can use a gateway device or we can even integrate it with a phone by making an application on mobile phone that can
35 process the translate human language to the language that BLE devices can understand This can help the Proxy Node can be flexible in the destination around the mesh
• End Devices and Low-Power Nodes are the devices that can function some proper purpose such as light-controlling, fan-controlling,… and also have the ability to communicate with other nodes through BLE.
BLE module that will be utilized
2.2.1 Introduction to ESP32C3 and reasons for choosing this module
According to previous section, we can get a conclusion about the requirements for the devices in the network Those requirements are:
• Devices need to be low power-consumption, having “deep sleep” mode and the capability of managing power-consumption in a smart way
• Devices need to have Bluetooth, Bluetooth Low-Energy and Wi-Fi modules integrated inside of it Moreover, BLE mesh supported is also a requirement for the module used in the device in the network
Due to those requirements, a module that can be appropriate for the requirements that we set is module ESP32
Microcontroller ESP32 was first introduced by Espressif Systems in 2016 and then its series quickly became a leading technology in IoT and embedded applications With integrated Wi-Fi and Bluetooth Low Energy (BLE) connectivity, the ESP32 enables easy wireless network connection for various IoT applications Its versatility is further enhanced by support for multiple programming languages, including C, C++, Python, and Arduino IDE Additionally, the ESP32 boasts low power consumption, making it suitable for battery-powered and energy-efficient devices With extensive peripheral interfaces and a robust developer community, the ESP32 offers a powerful and flexible platform for creating diverse IoT applications while prioritizing energy efficiency
Its series contains of many types of series for example ESP32, ESP32S2, ESP32S3, ESP32C3 and ESP32C6… And in those series, which is most suitable for our research is the ESP32C3 series due to the following reasons:
• Lower cost due to its reduction in the functionalities compared to other series
• Bluetooth, BLE and Wi-Fi integrated in the module
The following table specify the difference between ESP32C3 and ESP32S3 which is also released in 2020:
Supported Interfaces UART, GPIO, ADC,
PWM, I2C, I2S, SPI, LCD, DVP, RMT, SDIO, USB OTG, MCPWM DMA,
UART, GPIO, ADC, PWM, SPI, I2C
Typical PSI flash 64 MBits 16/32 MBits
CPU Dual-core Xtensa LX7 @ up to 240 MHz with additional vector instructions for AI acceleration ULP core to handle low power modes
Single 32-bit RISC-V (RV32IMC) core @ 160
On-chip RAM 512 KB 400 KB
On-chip ROM 384 KB None
Table 2:ESP32-S3 and ESP32-C3 Comparison
According to the above table, ESP32-S3 series have higher performance in both functionality and processing ability when comparing to ESP32-C3 However, when talking about power consumption, ESP32-C3 series have higher efficiency in saving energy Moreover, due to its reduction in functionalities, its price on the market is pretty low when comparing to the ESP32-S3 series in specifically and the ESP32 series in general but still fulfills our needs in this research Its low price can help this research to be easier for people
37 to access when they need to employ a big network of devices in their home or in smart home applications
2.2.2 Some further applications that can be applied in mesh
Based on its communication between the devices inside the mesh, we can have some further applications that can be applied in smart home for better living quality such as:
• Simultaneous functional group: A switch as a node in the mesh can control many End Devices For example, when we press the button number 1, 2 or 3 activities will be performed at the same moment
• Script: A group of functions will be performed respectively in an order that has been set up before This process will start once a particular action from the user is occurred
• Timetable: A script will start when the time set comes Due to the lack of
Real-Time Clock circuit in the ESP32-C3 series or in those devices in the BLE mesh, the time on mobile phone is needed for setting up schedule for BLE mesh
• Automation: A set of functions will be activated when the information from
End Devices satisfies the conditions that has set up before For example, the air-conditional and the fan will activated as the user arranged when the temperature sent from the sensor reaches a particular value and the presence sensor can realize there are human in the room.
Monitoring Tool
This can be regarded as a crucial component of the assistance we provide to guarantee the system operates effectively:
In this research, we use Python to design essential functions and algorithms, monitor and assess device performance and reliability, establish an interface, build servers with the Django web framework For creating web interfaces, HTML and CSS are also available
An administrator account is necessary for this tool's management and control
An IoT device provides registration data (Subscriptions) after connecting to the MQTT server using the Host and Port route and MQTTX software for mediation MQTTX can connect to and monitor multiple devices simultaneously The Django library, WebsocketConsumer, efficiently and flexibly handles real-time connections It relays data received from the IoT device via MQTTX through a Websocket connection, enabling easy access and interpretation of hex-formatted information based on the message structure (device data, status, plugins, etc.).
Furthermore, our team uses Render, a unified cloud, to create and manage solutions that make website management simple
Pilot experiments provide the basis for the tool's ability to track and assess the likelihood of being discovered The fact that we were unable to find any plausible examples of brief disruptions or total device connectivity loss attests to the tool's stability and dependability.
Results and Discussions
Network Simulation
In order to verify the connectivity of the network with the number of devices and device distribution in various conditions We designed a MATLAB model that simulates the connection process of the entire network Then simulating the connectivity with a large number of different spatially distributed capabilities With 100 allocated to each set of nodes
94, 275 and 844, the simulated network established a stable connection for all nodes
Figure 14:Network simulation with 94 nodes in an area of 50m x 50m
Figure 15: Network simulation with 275 nodes in the area of 50m x 50m
Figure 16: Network simulation with 844 nodes in an area of 150mx150m
Testing Network
In this testing network, we will utilize:
For designing those devices, we reuse the module from FPT Smart Home:
• Touch switch for Four-button switch
• Presence sensor that makes use of the LD2410S sensor module
• Smart Downlight LED for lightbulb
Figure 18: LED with BLE integrated
All of them make use of ESP32C3 module which supports Wi-Fi 2.4Hz and BLE Thus, we can reuse them as a normal ESP32C3 DevKit set
To enhance network capabilities, two key devices, the switch and presence sensor, will undergo internal redesign These devices, initially equipped with Bluetooth Low Energy (BLE) functionality, will be re-engineered to optimize performance for wireless network connectivity.
After redesigning the switch and the presence sensor, they will have the ability to connect to Wi-Fi and have a program that have a RPL protocol integrated in This will help these devices to be able of routing for message packets themselves
• Switch: o It can play the role of a Proxy Node, a Relay Node, and a Friend Node itself o For being a Proxy Node, it handles translating the requests or messages that user sends to the device through a smart phone that has connected to the switch through Wi-Fi
43 o For being a Relay Node, it can be used as a middle device for extending the mesh range For example, user can control the mesh from a very far distance through Wi-Fi with the Proxy Node connect to a Wi-Fi network In another situation, it can forward the message between two devices that are outside the range of each other o For being a Friend Node, it can store the messages in its memory then send them to the Low Power Node when that Node wake up o The switch also has RPL routing protocol installed inside of it Thus, it can determine the most efficient path for transmitting a packet itself
• Presence Sensor: o It has the same functionality as the switch o As a sensor needs to operate almost all the time, the role of being a Friend Node is very suitable for it
• Motion Sensor: o It acts the role of an End Device Its function is to realize whenever there are people in front of the sensor then send the message back to the switch then the switch forward it to user
• LED: o It holds the place of a Low Power Node as its radio is turning off most of the time The radio is only turned on after a time interval and then pulls the messages from the switch
To effectively monitor devices and facilitate communication, we employed FPT Smart Home's mobile application While the application's interface for controlling FPT devices remains visually similar, the integration of a RPL routing protocol within the redesigned button and presence sensor enhances data transmission reliability, setting them apart from the original devices.
Evaluating the result
After using the monitoring tool that we figured to record the message being sent from each device
Figure 20: Data structure of the message sent_1
Figure 21:Data structure of the message sent_2
When we start monitoring for longer periods of time, we could see that the connection have not turned down or being shutting down due to connection lost
According to the results, we can say that the connection is reliable enough for us to trust
However, the drawback that we can easily see from the transmission is the transferring speed Whenever a function is sent through the mobile application, or whenever the sensor sends back a message about having a motion, the latency is from about
2 seconds to 5 seconds, sometimes the latency is about 10 seconds This delay is considered to be the result of a power saving module as the MRHOF is quite complicated for a single ESP32-C3 module.
Conclusion and Recommendations
In conclusion, BLE mesh with RPL routing protocol is a effective way improve basic life for people BLE mesh provides flexibility in the network range and extending the network BLE is also a common technology that many people have known about and integrated in most mobile phone, which means BLE mesh is a model that can easily approach people and easily become popular When BLE network has RPL protocol implemented in, the scalability is increased when comparing to old BLE mesh This would open up many applications as the network is more flexible
For further development, we will set our goal to initiating a mesh based on Bluetooth 5.0, a better version of BLE but can not associated with BLE mesh Another goal is to optimizing the mesh in larger area, for bigger application such as a smart city
For further application, the first goal and also the primary goal for this model is making new devices to be available in the BLE mesh and minimizing the price for each device so that they can approach more people
BLE mesh technology holds significant promise in the medical sector In hospitals, it enables remote patient monitoring, empowering doctors to respond swiftly to critical situations Additionally, BLE mesh can seamlessly integrate into diverse fields requiring recording, monitoring, or automation that lack a fixed or flexible rotation pattern Its versatility makes it an indispensable tool for healthcare and other industries seeking enhanced monitoring and automation capabilities.
Abbreviations
ADC Analog-to-Digital Converter
DODAG Distance Oriented Directed Acyclic Graphs
DRAM Dynamic Random Access Memory
GPIO General Purpose Input/Output
HVAC Heating, Ventilation, and Air Conditioning
IEEE The Institute of Electrical and Electronics Engineers IGRP Interior Gateway Routing Protocol
ISM Industrial, Scientific, and Medical
LLN Low-Power and Lossy Networks
MP2P Multi-Point to Point
MQTT Message Queuing Telemetry Transport
MRHOF Minimum Rank with Hysteresis Objective Function
OSPF Open Shortest Path First
RPL Routing Protocol for Low-Power and Lossy Networks RSSI Received Signal Strength Indication
SDIO Secure Digital Input/Output
TWAI Time-triggered Controller Area Network
UART Universal Asynchronous Receiver-Transmitter
UDP User Datagram Protocol uIPv6 micro IPv6
USB OTG USB On-The-Go
WiLE Wi-Fi Low-Energy