5G Networks has a wide variety of meanings. First, let’s discuss what’s driving the need for 5G and what are the limitations of our current infrastructure are. The quantity of devices being added to the network is growing rapidly. A decade ago, we had a single device connected to the mobile network.
That was a smartphone. Today, we have 2 to 3 devices, such as a smartphone, smartwatch, and a tablet. As technology becomes smaller, more affordable, and capable of connecting to a mobile network, consumers are going to buy these devices and connect them to the networks.
Additionally, the content these devices share is becoming more data-intensive. Photos are also becoming higher quality, meaning larger file sizes. Sharing movies is now commonplace and new applications are continuously being developed that require large amounts of data to be transferred quickly.
The network can only accommodate so much device growth, and with additional radio channels required to add more users. Higher capacity backhaul networks are needed to move traffic away from the radio access network, to the internet and back again and all of this is expensive.
We will see that 1 of the design goals of 5G is to be more efficient with the resources currently available, and it’s not just consumers that are going to drive the need for 5G.
One of the most talked-about technology advancements that require 5G networks is self-driving vehicles. Self-driving vehicles will require a low latency data network with the ability to provide quality of service or QoS.
QoS is a method of prioritizing network traffic. In this case, QoS would provide a very high priority to vehicle communications and provide a much lower priority to something like streaming video traffic.
This way, vehicles can communicate quickly to prevent collisions while a user streaming a video would likely not even notice a brief network delay while viewing, as videos typically buffer content for smooth playback.
Today, we are unable to provide this quality of service feature. Additionally, businesses need next-generation mobile networks also. In the retail and restaurant space, the increased reality on smartphones could offer special discounts to a user when they are near a business.
Artificial intelligence voice assistance will have lower latency access to the network making suggestions, based on location data and user requests much more efficient and effective.
Manufacturing, healthcare, and other verticals will also have a whole new set of needs, based on massive IoT or Internet of Things device deployments. These are often associated with home automation gadgets like lightbulbs or home security cameras.
In a manufacturing plant, these IoT devices take the shape of sensors and controllers, and when deployed on a massive scale, will require a high-speed low latency reliable network to feed data back to an artificial intelligence system that can then provide feedback for efficient plant operation.
Therefore, there are new markets that 5G Networks can accommodate based on the design objectives of 5G Networks, something that we cannot currently do. One of the reasons we cannot accommodate the requirements is that we are don’t have a low-latency network.
Latency refers to the amount of time it takes a message to leave an end user’s device, reach the intended network target, and return. One of the issues with the deployments is reaching the internet from a user’s handset requires moving traffic to a regional point of presence.
This allows mobile characters to count the data so the user can be billed accordingly, as well as remove header information from the messages used to move it through the mobile network, which is not required and not desired to move traffic across the internet.
The traffic from your smartphone often has to travel hundreds of miles from its source just to reach the internet and then take the same path back again. When you are directly connected to the internet like at home or in an office, network traffic typically doesn’t have to make this expensive trip to reach the internet making these communications have much lower latency.
If a cell site could have its internet, access to the internet would be more effective in several ways. First, the cost of moving the data would be reduced as you do not require expensive backhauls to a regional point of presence.
Additionally, access to the network resources would be much lower latency as the traffic wouldn’t have to travel hundreds of miles back and forth again just to reach the internet.
5G mobile networks require this low latency, and therefore, require rethinking how the internet is delivered to the cell site. 5G, along with another technology called multiaccess edge computing, or MEC, will allow this to happen. Now that we have a general understanding of the need for 5G and a few of the limitations of LTE, let’s take a look at the design objectives outlined by the ITU.
The ITU has outlined four broad objectives for 5G. First is service awareness. This is the technical component of 5G. It outlines speed and latency requirements, security, growth, energy efficiency, among other things.
Next is data awareness. This objective is referencing the large quantity of data being created by the end-users and the devices like pictures, movies, or sensor data, as well as the data available on a local network or the internet.
Having high speed, low latency, highly reliable access to this data is critical for next-generation technology to operate correctly. The next two objectives are much less technical. Environmental awareness focuses on energy efficiency and optimization of the technology.
Powering a cell site is expensive and there are tremendous cost savings to be made by making more efficient use with power. Making these systems more efficient and optimizing resources means less electric usage, meaning lower power bills for the cell carriers, and being sensitive to global environmental awareness.
The last objective of the ITU is social and economic awareness. Access to the internet is critical to the success of an individual or a culture. This objective is asking that organizations be sensitive to providing a network that is accessible to as many people as possible and so that the cost is not prohibitive to use.
You should see with these design objectives from the ITU that 5G is bigger than just creating a high-speed, low latency network. The objectives are designed to account for a changing global network, improving efficiency, and bringing mobile networks to more people and business verticals. There is an amazing opportunity worldwide for providing a quality, high speed, low latency mobile network.
Let’s move on to the more technical aspects of 5G. The ITUs set the general design objectives for 5G, and then another group, the 3G PP, or Third Generation Partnership Project, has been using those objectives to create realistic technical design goals.
These goals align with what hardware manufacturers can build, as well as set some milestones, which will allow mobile carriers to deploy 5G technology alongside helping to reduce rollout costs and allow engineers time to finalize hardware designs that meet the goals of the final specification for 5G called the IMT 2020.
2020 here is referencing the goal to have these designs completed by the year 2020. Let’s take a look at some of the important features of these technical goals. The first major and likely most important design criteria are for speed and latency for 5G networks.
The guidelines state 5G networks will allow a user to enjoy a download data rate of 100 Mbps with some types of communication, able to reach speeds of more than a gigabit per second. Additionally, the latency on the network will be less than 20 ms with some applications demanding ultra-reliable, low latency communication, or URLLC.
One of these applications is self-driving vehicles which will require latency of less than a millisecond. The second feature is to provide secure and reliable communications. Because of the new uses for 5G networks, it’s supreme that the integrity of the data passed on the network is maintained.
Tampering with data on the 5G network has the potential to cause accidents with self-driving vehicles or have catastrophic consequences in a manufacturing plant using massive IoT devices to collect information used to make decisions about plant operations.
This information must be secured. A third important design feature is for future growth. The number of devices connected to the network will grow as will the demand for bandwidth.
The specifications for the rollout of 5G allow for the use of existing technology to bring the first generation of 5G networks online and then eventually migrate to a standalone 5G technology.
Additionally, the 3G PP group has set some milestones to allow for the gradual rollout of the technology, which will ramp up the ability to accommodate new technologies over time, instead of having a giant leap forward, which is both expensive and unrealistic based on currently available hardware.
The last important technical design feature is for energy efficiency. Powering a cell site is expensive. Adding more capacity to a site will ultimately result in greater power usage.
The engineers designing the hardware will make use of several technologies to reduce the energy footprint for delivering 5G networks. Now that we have a general understanding of the design goals of 5G, let’s move onto the more technical components of 5G networks.
To deliver the speed and latency requirements of 5G, engineers are developing equipment that will make use of several technologies. Let’s take a look at five of the most important technologies.
We’ll examine millimeter waves, small cell deployments, massive MIMO, beamforming, and full-duplex communication. First, to deliver wireless communication, we need a piece of the electromagnetic spectrum.
Some of the spectra are divided into channels and these channels are regulated by the FCC in the United States and by other regulating bodies around the world.
To make use of these channels, carriers must pay the regulating bodies a fee for use, as well as work with a limited spectrum of usable channels. Today, carriers use microwave bands.
We start with ultra-low frequency bands, and then it moves into ionizing radiation. It means that the wavelengths become smaller and smaller. Right where our most current cellular technology operates, we have to move a bit, where we have millimeter waves, which exist much closer to the infrared spectrum.
The most enticing feature of millimeter waves is the tremendous availability of channels in this spectrum. This is a huge benefit for mobile carriers, however, this comes with a challenge.
Millimeter waves have difficulty traveling through objects. The ultra-low frequency waves are generated using an antenna that’s a mile or longer and these waves can easily penetrate objects, whether it be the earth or water or something else.
This technology is used to communicate with submarines because it can easily travel through objects. However, if you consider the visible light spectrum, we can easily recognize that light waves have extreme difficulty penetrating objects, which is why we have shadows.
The waves just longer than visible light are infrared and just longer than the millimeter waves are. TV remote controls make use of infrared waves to send a signal to your TV, and if there is an object between the path of the remote and the TV, the TV won’t receive the signal from the remote.
Likewise, millimeter waves being very close to the infrared spectrum, also have difficulty penetrating objects. The additional challenge of millimeter waves in the range. No more than a kilometer from the source.
Therefore we have this short-range and difficulty traveling through objects. There are two ways we can combat the limitations of millimeter waves. One of the solutions is to make the cell size very small and deploy a large number of radios and antennas to provide the necessary coverage to an area.
This is a somewhat simple solution, however, it introduces yet another problem. When we introduce a large number of radios in a location where there are buildings and other stuff for the signal to bounce off of, we end up with signals coming from many different directions, which has the potential for creating interference.
So although the small cell size would be a benefit to 5G deployments, there are some additional challenges to overcome. This is where the next few solutions come into play, which is pretty attractive.
Using multiple antennas, one can mathematically calculate the direction a signal is coming from, its strength, and the location of the device sending the signal.
It can do this even if there are buildings and other objects in the signal path. Moreover, that same math can be used to a general signal using multiple antennas to erect a high-powered signal directly at the sending device reflecting the signal off of the building and other objects as necessary.
This is a really interesting technology and allows for some significant steps forward in mobile wireless technology. Two separate technologies work in conjunction with each other. One is called massive MIMO.
MIMO is just multiple inputs, multiple outputs, and means using many antennas to send and receive signals. By using multiple antennas and some mathematics in the processing of the transmit/ receive hardware, we can create directed beams of signal, boosting the signal where it’s needed, and canceling out the signal where it’s not needed.
This is called beamforming and is the second technique used to help make millimeter waves more effective. By creating high powered beams of signal directed at the intended device, millimeter waves can be more powerful and send a stronger signal to devices that need them.
We can use both massive MIMO and beamforming in waves besides millimeter waves, and 5G networks will likely do that with existing channels in the microwave spectrum too. However, because of the nature of millimeter waves, massive MIMO and beamforming can help enhance the performance of those smaller waves.
Yet, when it comes to millimeter waves, even with massive MIMO, small cells and beamforming, millimeter waves still do very poorly when penetrating objects.
What this means is that if a user is inside of a building or in the shadow of a signal, the signal will drop off quickly as will communication between the device and the cell site.
An option to solve this is to use a femtocell. This technology is currently used for customers who are in an area of poor cellular coverage. A femtocell is a small radio, deployed inside of a building and then typically connected to a high-speed internet connection.
The femtocell device builds a connection over the internet to the carrier, and then a customer’s handset will connect directly to the radio in the femtocell. It effectively extends the carrier’s network into a building.
This could be useful for 5G and millimeter-wave use, however, it may not be ideal due to the extremely large number of femtocells required to provide coverage inside of every building where coverage might be needed.
Because of this, current microwave channels used today will likely continue to be used in 5G deployments to accommodate users inside of buildings.
Millimeter waves will be useful in outdoor deployments, especially in cities where there are dense populations and lots of buildings. Small cell sites mean that the available channels can be reused in an area that’s more than the range of that signal.
For example, if a millimeter-wave channel can only travel 1 kilometer, then you can reuse that same channel and a radio that’s more than a kilometer away. This means that a carrier can reuse the channels and have a broader deployment allowing for more users.
Another technology that would be used in 5G networks is to be more efficient with full-duplex communication. Understanding duplex is simple. Imagine that you have a walkie talkie. When you and your friend would be talking to each other, one could speak, the other could listen.
If you tried to speak when your friend was speaking, this just shut down the communication and no messages were received. This is called half-duplex communication, meaning only one signal could be sent at a time. The telephone, on the other hand, is a full-duplex. When you use the telephone, both; you and the person with whom you’re speaking can talk at the same time.
This may make conversation challenging for a human, however, with network communications, being able to send and receive data on the same channel at the same time doubles the use of the channel making for more efficient communication.
Currently, we do use full-duplex. It’s implemented using FDD, or Frequency Division Duplexing. The way this works is one channel that will be used for downstream communications.
These are the communications that come from the tower to the user’s handset. When you’re surfing the web on your phone and the information coming from the internet to your phone, will use one channel.
Let’s say it’s channel A, and then the upstream communication from your handset to the tower will use a separate channel to send this information. In the case of surfing the internet on your phone, you may fill out a form or send a text to a friend, it will use a separate channel for the upstream communication, call it channel B.
This way, you can both download and upload information at the same time, maybe you’re listening to a podcast while texting a friend, and your handset will seamlessly transmit and receive at the same time.
Nevertheless, FDD requires two channels to provide this full-duplex communication, and each channel can only send or receive information. This is inefficient, and the reason we are creating full-duplex communications here is that we’re using two half-duplex channels.
The upstream channel can only send data upstream, and the downstream channel can only send data downstream. Doing this creates inefficiency. A user handset has a limited need for sending data from the handset to the radio.
Text, photos, forms, and the protocol overhead from sending IP traffic to and from the internet are all relatively small compared to the amount of data downloaded to surf the web, browse streaming videos, or examine rich content on social media sites.
To use FDD, two communication channels are being provisioned and only one of them is being used to its full potential leaving the upstream channel in light-duty mode.
There are other options to allow for full-duplex communication to be used in a single channel. This is done by creating separate time slots for upstream and downstream communications.
This is called time-division duplexing, or TDD. With TDD, we no longer need a separate upstream and downstream channel, and instead, we can take the two channels used in FDD and now use each of them as both up and downstream, effectively doubling the capacity and creating massive efficiency gains.
TDD works by quickly switching between sending and receiving data, however, this happens extremely quickly, allowing data to effectively be both sent and received simultaneously.
Additionally, using TDD along with massive MIMO has additional benefits of scalability. TDD with massive MIMO allows a carrier to deploy more antennas to accommodate more handsets or other devices.
Research is done by Emil Bjornson, Eric Larsen, and Tom Marzetta, all experts in signal processing and MIMO discover that using TDD and massive MIMO you can add as many end-user devices as needed as long as you add more antennas to accommodate this, and this is something not possible with FDD.
You reach a limit where adding antennas to the MIMO system no longer accommodates more end-user devices in FDD. So, just discussed five technologies that all work in conjunction with each other.
5G will make use of millimeter waves, small cells, massive MIMO, beamforming, and TDD full-duplex communication to deliver services to users and accommodate the needs of the next generation of devices and technology.
Initially, this 5G will be rolled out on top of current technology and incorporate some of the features of 5G, but not all of it. The first generations of 5G networks will likely be able to offer high-speed connections, however, reducing the latency on 5G networks will require using another technology like multi-access edge computing, or MEC.
Sometimes, this is called edge computing, and there will be further discussions that will focus exclusively on MEC and how that technology will be used to improve network performance.
5G is a mandatory upgrade of mobile networks to accommodate next-generation devices. As I discussed, the ITU has design standards to build the next generation network and the 3G PP has been tasked with the technical design to achieve these goals. The ITU, 3G PP, hardware manufacturers, and mobile carriers will all work together to ensure the success of this next generation of mobile networks.
