Network for IoT

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Now let’s take a look into IoT Network Technology. And to explain this I’m gonna
use the picture behind me. In an IoT Network well,there’s many ways to look at it. But, some of the major technologies are, wireless personal area network Things like 6LoWPAN, ZigBee, Bluetooth,are definitely gonna be used.

In addition, on a slightly larger wireless network scale, Wi-Fi, wireless LAN technology, is going to be used and needs to be supported.

Then as, we go to the larger scale network, the backbone, in addition the mobile communication network domain. Then smartphones and mobile communication phones will be used and they will be connected to the base stations. The base stations will provide connectivity to the wider network, the internet.

And considering this, we need to think about many options. One thing is that smartphones are equipped with Bluetooth and Wi-Fi. So therefore you can think of IoT Network the most simple topology control will be a wireless pan which is either like a Bluetooth or some other type of network that is connected to a smartphone, and the smartphone will bring that signal up and connect it through LTE, or 4G/3G, to the base station, and the base station will connect to that wide array network, which is the internet. So therefore, you can see as one technology linking
on a technology of something else. And that’s what’s shown in this figure right here.

wearable IoT Network device

Now we go into wearable IoT Networks. And this is one example that actually
brings what I just explained into reality. A wearable IoT Network device. Well, it’s something like this Wearable devices such as our shoes, our watch, our glasses, our belt, these things can be used to detect biometric information because they’re close and very attached to our body. And they can sense what’s going on. These devices can send through, let’s say, Bluetooth technology to the smart phone that’s in my pocket. Or that’s on some other place inside of a pocket on my coat or in my pants or something like that. In that case, the Smartphone will be able to pick up this information and it will be able to use it’s mobile communication link to send it to a base station. The base station, which is connected to a wide area network and the Internet, is going to be where the information connects to any other place I need in the world. For example, if I’m using my watch and also my shoes as well as my belt or something like that that I have attached to me to monitor my health condition that health condition can be sent wirelessly to my smartphone. My smartphone will send that information to the base station, mobile communication base station which
will be connected to the internet. And that information can be delivered to a control center or medical server. Something where if something happens to me, they will know and they will be able to provide immediate support. A smart device can be used to collect the information that communicates with control centers or like a medical center and this will be how everything gets connected together. Now let’s look at the component technology. And we’re going to start with Wi-Fi, the Wireless Local Area Network. Wi-Fi is a Wireless Local Area Network technology that is based upon the I EEE 802.11 standards. A Wi-Fi device. Well smartphones, smart tabs, smart other types of notebook computers and things like that, are all equipped with Wi-Fi. Application areas would include home, school, computer laboratory, office building, and so many other places. Wi-Fi devices and their Access Points have a wireless communication range of about 30 meters indoors. If you look at the Wi-Fi data range, it is based upon the protocol type.

Wi-Fi, Bluetooth is to replace WIRE

For example, 802.11a, b, g, n, ac and ad. Well, look at their data types over there. Their data rates can be 54 Mbps, 11, 54, 150 and also 866.7 Mbps. When you go to the futuristic 802.11ad, well, you’re reaching up to like 70, 7 Gbps, which is at a much higher data rate. Now we look at Bluetooth. Bluetooth is a wireless PAN, a Wireless Personal Area Network protocol. And it’s designed by the Bluetooth Special
Interest Group, the Bluetooth SIG. This replaces cables connected many different devices. So with Bluetooth basically cable free becomes one of the major focuses. For example, headset to mobile phone going wireless or wireless headset, wonderful. Heart monitors and other medical equipment that I have will be connected to my smartphone using the Bluetooth link. That’s basically what I’m talking about when I talk about wireless Bluetooth connectivity replacing wires. Now, Bluetooth’s standard area network range is about 10 meters for indoor applications and things like that, but when you go to Bluetooth. 4.0, well you’re talking about an extended
range of up to about 50 meters. Bluetooth Low Energy, which is a part of Bluetooth 4.0 standards, this provides reduced power consumption and cost reduction while maintaining a similar communication range. That’s wonderful. Once again, just like Wi-Fi, Bluetooth has different data rates as well. Just taking a look at Bluetooth 2.0,
3.0, 4.0. Well 2.0 with EDR, this can provide a two point win, 2.1 Mbps data rate. Bluetooth 3.0 with a HS well this can support 24 Mpbs. Bluetooth 4.0 well this achieves up to 25 megabits per second of a data rate. Now let’s take a look at
IEEE 802.15.4 standards and this is used in ZigBee, 6LoWPAN and all of these other type of applications wireless communication protocols. We’re going to focus on two of the most popular ones which is ZigBee and 6LoWPAN. Why 802/15.4? Well, it’s a low cost, low speed, low power, wireless personal area network protocol and it can be used in many good ways like supporting works and IoT technology. Now, what type of device types does this 802.15.4 standard have? There’s basically two. One is a full function device and the other is a reduced function device. Now, a full function device is equipped with full functionality. It can send, receive, route data, and form clusters. It can serve as the PAN coordinator. That doesn’t mean that it will always be a PAN coordinator. It may elect to or sometimes if it sees somebody else, some other FFD is already Doing that role, then in order to save energy, it may not do PAN coordinator operation. It may just work as a full functional device. And then later on if that device, that taking the PAN coordinator role, if that role is released and
some other device needs to take it, then the FFD may volunteer to take that role. Now, the next type of device is RFD, reduced function device. Now, this has a reduced
functional protocol compared to the FFD protocol stack. This can only communicate
to full functional devices. It cannot serve as a PAN coordinator,it serves a role as a simple sensor or switch device, and it cannot provide routing functionality. Network topology wise, well, with the 802.15.4 you can form a star network topology,
a peer-to-peer, P2P network topology. Also, we using a lot of FFDs, well, and also the P2P extensions, well, you can form a mesh network. In addition, for a large scale network, you can form a cluster tree. In addition, the role of coordinator is very important. This controls the 802.15.4 network, a special form of a full functional device that needs to be taken, and it’s a typical FFD functions and added on with network coordination and service features. Once again, an FFD will need to take this role of coordinator to play a bigger role in controlling the network. Now, let’s take a look at network topologies but first, start with the star topology. Here, you see a full functional device, the devices that are full functional devices are colored in blue and the reduced functional devices are colored just in white. Now, as you can see, a full functional device in the middle provides the star topology formation. Nodes communicate through a central PAN coordinator and that’s the FFD in the middle. Now P2P topology. Here, you can see that nodes communicate through the PAN coordinator, and through point-to-pont links that they establish on the sides. Here, extension of the star topology is basically what enables the P2P topology to exist. Next is cluster tree topology. Here, among the full functional devices, a PAN coordinator takes the major role. And as you can see, it is where different clusters are formed based upon the full functional devices. And as you can see, the PAN coordinator connects the individual full functional devices that are forming the star or P2P networks that are forming the clusters. The cluster trees are similar to stars, though RFD devices are only allowed to connect at the outermost branches. The diagram shows that the FFD connects to the coordinator and a FFD can have connections to multiple end devices. Now, to look at the frame format,this will give you a little bit about what is actually used in the coordination for these type of functions. And as you can see here, well, for the overall structure the maximum frame size is 127 octets, 127 bytes, the maximum frame header is 25 octets. As you can see, the frame control field is expanded out below where in the frame control field there’s a frame type and various fields. Among these fields, the security enabled
field, that’s interesting and important. In addition, we can see the Intra PAN field that’s in there. It also includes the app request,frame pending, destination address mode, and source address mode, and other reserved fields. Now, going back to the general frame
format above the frame control field, we see that there’s a sequence number and
there’s a destination PAN identifier, and also there’s
a source PAN identifier field. Then, we have destination address,
source address, and this is where you see the frame payload
goes in, and that’s a variable field. At the end, for protection, due to errors,
we have a frame check sequence. Now, let’s look at ZigBee and
6LoWPAN because these devices use the 802.15.4 layer
at the lower layers. Now let’s look at ZigBee first. This is supported by the ZigBee
alliance and ZigBee adds on the upper layers which are the application layer and
the ZigBee network layer, on top of the medium access control and
physical layer that are established in
the IEEE.802.15.4 protocol. Now here,
ZigBee provides the upper layers, and of course different type
of service operations. ZigBee works well in isolated
network environments. In other words, if it’s an isolated
network, ZigBee can use, it can be used to form an IoT or a sensor,
wireless sensor network connection. ZigBee network topology include star,
mesh, cluster tree, where the star network is the basic
common topology that is formed. Mesh or P2P networks can provide high reliability because they can
support multiple routes between nodes. Then there’s the cluster tree network
which is a combination of star and P2P topologies. As you can see, ZigBee network topologies
are dependent upon the network connectivity that are provided
by the IEEE 802.15.4 protocol. Now, we’re gonna look into 6LoWPAN. Now, what is 6LoWPAN? Well, 6LoWPAN stands for IPV6 over low
power wireless personal area network. So, it supports IPV6 packets over the IEEE 802.15.4 wireless personal area network. It enables IPv6 IoT wireless
network support based upon low power design aspects for
good battery operated IoT devices. This means that this is good for
battery operated IoT devices. Means that typically,
the low power consumption is going to be used to
extend the battery life. 6LoWPAN is an IETF standard. The IETF is
the Internet Engineering Task Force. It is one of the two task forces, the IETF
and the IREF belong to the Internet architecture board which
are under the United Nations. And in here, this uses,
the 6LoWPAN standard uses the IEEE 802.15.4 wireless PAN technology for
its two basic layer operations. Now, wireless PAN direct
connection to IPv6 Internet, this is what we’d like to achieve,
and this is what 6LoWPAN can provide. IPv6 features can be used to support
wireless personal networks if. They are connected together, and
that is what 6LoWPAN attempts to do. You can use IPv6 security features. You can use the IPv6 naming,
addressing, translation, lookup, and discovery function that IPv6 already has,
and that’s wonderful. Now here are some characteristics
that we need to consider. The small packet size that
supports the 16 bit short and the IEEE 64-bit extended
Medium Access Control addresses are typically what are used
in 6LoWPAN packets. Also, low data rates of 20, 40, or 250 kbps are the major domain of
the data rates that can be served. Network topology-wise,
Star and Mesh topologies. And this is because we’re
using the 802.15.4 standards. This is good for
low power battery operated nodes. And also relatively low cost devices
can be developed from this technology. One thing we have to consider is header
compression and this is because 6LowPAN and IPv6 packets, we need to have
some packet size matching required. What do I mean? Well take a look at this, IPv6 minimum
packet size is going to be 1,280 octets. The IEEE 802.15.4 has an MTU of a maximum transmission unit. Which is the maximum packet
size is only 127 octets. And as you can see there’s a big
mismatch of the packet sizes. Now just looking at the IPv6 header. Well, this is a 40 octet minimum length
with no option extension fields added. Still it’s 40 octets, and that’s way to
big to send over an IEEE 802.15.4 packet. Because look, among the 127 octets, that
itself is gonna occupy too much space. So what we need to do here and what 6LoWPAN provides is
header compression technology. It works like this, you compress the IP
address because the IP address is long and you compress it when it can be derived
from other header field information. Also, you wanna compress the prefix
part for link local addresses. You may even want to totally
omit the 128 bit IPv6 address field when it can be provided
from the link layer address information. In addition, you can try to compress
other common header fields. Like the TCP, UDP and ICMP header fields. And if you do that you can save
a lot of the header information. It can be kept and used in the operation,
but not transmitted over the wireless personal area network
every time a packet is transmitted. Now I hope you have a better insight
into what makes IoT networking possible. And it’s from a unique combination
of wireless personal area networks, like 6LowPAN, ZigBee, and the IEEE 802.15.4 protocol that
runs the Medium Access Control and the physical layer operations for
6LowPAN and Zigbee connectivity. In addition, we studied about
wireless LAN Wi-Fi technology, which is a local area network,
wireless local area network protocol. And on a larger scale, mobile
communication technology, such as LTE, that is used to provide connectivity
to the internet, the wide area network. I hope that you can see how these
technologies need to work together to provide IoT connectivity. These are the references that
are used to prepare this IoT lecture. And I hope that you can use them if
you’re interested in further studies. Thank you very much. This wraps it up for IoT but there’s
other topics that are included in this specialization package and I hope that
you refer to them for further studies. Thank you.

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