Inception of 5G brings network densification back into focus

With 5G getting deployed across several countries, there will be challenges and benefits associated with the setting up of the 5G infrastructure. With the inception of 5G and its early implementations using a combination of 4G and 5G technologies, mainly referred as non-standalone deployment (or NSA) brings network densification back into focus.

Here, Alok Kumar Sinha, Product Director, Network Analytics, Subex, tells us more. Excerpts:

V&D: How will 5G networks improve densification over 4G LTE, and what are the benefits?

Alok Kumar Sinha: Network densification is not a new concept. It gained traction since the inception and promising growth of LTE networks. In order to cope up with the increasing number of mobile broadband data subscribers and bandwidth-intensive services competing for limited radio resources, the necessity of heterogenous network (HetNet) was considered by 3GPP and standards in subsequent release offering the key capabilities to support HetNet deployment was released.

In heterogeneous networks the cells of different sizes, referred to as macro-cell and small cell (micro-cell, pico-cell and femto-cell); listed in order of decreasing base station power. The actual cell size depends not only on the eNB power but also on antenna position, as well as the location environment; e.g. rural or city, indoor or outdoor.

In a Hetnet ecosystem, network densification with small cells are primarily added to increase capacity in hot spots with high user demand and to fill in areas not covered by the macro network – both outdoors and indoors. They also improve network performance and service quality by offloading from the large macro-cells. This results in a heterogeneous network with large macro-cells in combination with small cells providing increased bit rates per unit area.

Inspite of the standards and specifications made available by 3GPP to support HetNet in LTE network, the HetNet deployments did not scale in volume, one of the primary reasons behind it could be the continuous evolution and subsequent deployments of latest versions of LTE technology like LTE-advanced and LTE-Advanced pro.

Now, with the inception of 5G and its early implementations using a combination of 4G and 5G technologies, mainly referred as non-standalone deployment (or NSA) brings network densification back into focus. Enhanced mobile broadband (eMBB) driven FWA (fixed wireless access) being the initial preferred application of 5G by many communication service providers(CSPs) fuel in the momentum to 5G network densification and make it more cost effective, with its support for mmWave, unlicensed access, integration with Wi-Fi, and RAN virtualization.

5G-driven densification also encourages new business models. Some of these will involve enterprise private networks. Some will be neutral host, small-cell deployments, etc., where multiple operators share the network access infrastructure or, more commonly, the backhaul.

One of the key benefits of 5G densification, in combination with LTE network, is the enhancement of customer experience, as faster throughput data demand is skyrocketing at an exponential rate, so is the pressure on carriers to keep up and retain customer satisfaction, all while containing costs and maintaining a healthy revenue profile.

It has quickly become apparent that in order to stay competitive and in order to meet high consumer data traffic needs, CSPs are finding the need to evolve their approach to providing mobile services. For CSPs to meet their goals, small-cell solutions would come into picture to help mitigating costs and boost data traffic in the network.

Another factor that brings strong focus on 5G network densification is the fact that CSPs are thoughtful in how they deploy new network resources in a highly competitive industry where the return on investment is an important consideration. Densification enable CSPs to provide “Targeted Services”, densifying their network with small-cells or providing fill-in coverage where needed for a fraction of the cost of deploying additional macro base stations.

V&D: How can operators invest in new equipment that would support spectrum bandwidths, laying fiber optics cables, and help in development of cellular transmission technology?

Alok Kumar Sinha: Mobile backhaul is evolving from a static, linear connection to a programmable mesh interconnecting all mobile and cloud elements dynamically. The investment in transmission technology must evolve, because the radio access and packet core elements it interconnects are changing to support new services and industry verticals.

In the course of this evolution, traditional distinctions between fronthaul, backhaul, and backbone, are blending toward an end-to-end common architecture.

In this evolution, open RAN (O-RAN), virtualization and multi-access edge computing (MEC) may be the factors that will have the largest impact on the transport infrastructure as we move to 5G. Not only do they alter how networks work, they disruptively change where and how network functions and content are physically located.

This is a game changer for transport, because it alters what is being transported across various parts of the network, not just how much traffic or with how much latency. Furthermore, this is not a one-time, step-like change, but a deeper change, from a fixed, deterministic transport infrastructure to a flexible infrastructure that can reconfigure itself in real time in response to traffic fluctuations.

While virtualization and edge computing will change the wireline infrastructure, the 5G air interface will change its scale. The 5G RAN will carry impressive amounts of traffic across the network, and will concentrate this traffic very tightly in dense hotspots.

* Multiple drivers will jointly enable the higher capacity of the 5G RAN
* Antenna technologies, such as massive multiple-input multiple-output (MIMO) or beamforming to improve spectral efficiency
* Sub-6 GHz unlicensed spectrum, used opportunistically, will complement licensed spectrum, with a combination of 5G New Radio (NR), LTE, or Wi-Fi for the air interface
* Integration across interfaces and bands includes sub-6 GHz unlicensed bands
* More advanced carrier aggregation and dual connectivity will further improve the allocation of network resources
* The use of mmWave for access has the potential to radically expand network capacity in hotspots.

As 5G evolves, wireless networks will become more powerful, pervasive, dynamic, and flexible. It will also become more complex and require more effort and more sophisticated tools to optimize the use of network resources. That’s where analytics, AI, and automation come into play. It offers operators tools to manage complexity, and to benefit from the new capabilities and opportunities for differentiation and new revenue streams that this complexity brings.

In a 5G ecosystem, a CSP must plan its transmission network investments toward virtualization, MEC, O-RAN and advanced analytics tools for exceptional transport network management to offer superior services to consumers and enterprises.

V&D: Why are some operators opting for low-band 5G spectrum instead of the so-called mmWave technologies?

Alok Kumar Sinha: 5G deployment is an evolution that builds on all spectrum assets. CSPs need to be able to make best use of the performance characteristics of each band to support their business strategy while maintaining coexistence between all the technologies deployed in the network.

Assets for mobile communications in term of spectrum comprise of Low-band, mid-band, and millimeter wave and these all refer to different segments of the electromagnetic spectrum. All three are within the radio wave range and a classification example is provided below:

Spectrum classification for 5G in US:
* Low-band: 600MHz, 800MHz, 900MHz
* Mid-band: 2.5GHz, 3.5GHz, 3.7-4.2GHz
* Millimeter wave (mmWave): 24GHz, 28GHz, 37GHz, 39GHz, 47GHz.

Worldwide, 5G needs spectrum within three key frequency ranges to deliver widespread coverage and support all use cases. The three ranges are: Sub-1 GHz, 1-6 GHz and above 6 GHz. Sub-1GHz spectrum is needed to extend high speed 5G mobile broadband coverage across urban, suburban and rural areas and to help support IoT services. Above 6 GHz is referred as mmWave.

Capitalizing into mmWaveis one of the strongest breakthroughs leading to the 5thgeneration of wireless technology, and it allows for some lightning fast, gigabit speeds.

For 5G on mid-bands and low-bands, improvements will be more incremental. 5G technology is more efficient than 4G LTE on existing bands, but not by a huge amount. 5G also is designed specifically to piggyback on the 4G network, with the aim of strengthening, rather than replacing 4G speeds.

Eventually, like any wireless technology, it will become dominant as CSPs gradually upgrade their network towards much more consistently high speeds.

5G pioneers, AT&T and Verizon, have used millimeter wave for their initial deployments, but, as Sprint and T-Mobile get into the game or make plans to do so, they have touted their ability to quickly cover broad areas by using lower-frequency spectrum. Although, that didn’t stop T-Mobile from spending more than $842 million to obtain millimeter wave spectrum in the recent auctions! Likewise, AT&T and Verizon expect to deploy 5G in lower-frequency bands, as well as in the millimeter wave band.

Verizon had amassed licenses for an average of 160 MHz of spectrum in all bands nationwide. In comparison, the company used four segments, apparently each comprised of 100 MHz, for a total of 400 MHz of millimeter wave spectrum to support its initial mobile 5G launches in Chicago and Minneapolis.

5G services will struggle to reach beyond urban centers and deep inside buildings without lower-spectrum. The European Commission supports the use of the 700 MHz band for 5G services and in the United States the 600 MHz band has been assigned and T-Mobile has announced plans to use it for 5G.

Spectrum from 1-6 GHz offers a good mixture of coverage and capacity for 5G services: It is vital that regulators assign as much contiguous spectrum as possible in the 3.3-3.8 GHz range and consider the 4.5-5 GHz and 3.8-4.2 GHz14 ranges for mobile use. The 2.3 GHz and 2.6 GHz bands should also be licensed to operators for 5G use.

Spectrum above 6 GHz is needed for 5G services such as ultra-high-speed mobile broadband: 5G will not be able to deliver the fastest data speeds without these bands.

V&D: It is said despite 5G offering a significant increase in speed and bandwidth, its more limited range will require further infrastructure. How can this be overcome?

Alok Kumar Sinha: Millimeter waves are wavelengths on the electromagnetic spectrum between 30 GHz and 300 GHz, allowing for high frequencies over narrow wavelengths signal degradation is one of the top challenges associated with 5G NR mmWave coverage rollout, with environmental obstacles hindering 5G signal spread.

Many of these obstacles have been addressed or are inconsequential for existing 4G networks. Due to the associated multiple kind of losses, it appears that 5G small cell may need to be deployed on every city block in urban city, to properly address the obstacles as well as the usage demands of a metropolis. We have discussed about densification and these steps are going to sort out some of the hurdles.

To deliver full-bandwidth 5G NR using mmWave technology, engineers need to optimize antennas, components, power supplies, and microprocessors associated with small-cell distribution. Increased deployment of mmWave small cells will fill in major coverage gaps, bringing more intelligence to the network edge.

This will enable the collection of more information about neighborhoods and the environment, and how users are moving throughout these spaces. With artificial intelligence (AI), machine learning (ML) and deep learning analyzing the data from these networks, operators will be able to make predictions and improvements to their coverage over time. These will allow 5G NR networks to become increasingly reliable over their lifespans.

V&D: How can we have better 5G antennae that currently handle more users and data, but beam out over shorter distances?

Alok Kumar Sinha: The end-user performance requirements continue to increase, putting high demands on the radio access network (RAN) to deliver increased coverage, capacity and end-user throughput. Since data usage is currently increasing at a much faster rate than corresponding revenue, CSPs must evolve the RAN in a way that enables a reduced cost per bit while meeting new demands for end-user performance.

The timing is now right for the telecom industry to make the technology shift to advanced antenna systems (AAS). The key reasons for this technology shift are the superior performance of AAS in both uplink (UL) and downlink (DL) and the feasibility of building AAS cost-effectively.

The shift to AAS is enabled by technology advances in the integration of baseband, radio, and antenna, and a reduction in the digital processing cost of advanced beamforming and MIMO. AAS is a powerful option for CSPs that want to improve coverage, capacity and user performance using existing network sites. Many CSPs choose this strategy as it is often difficult, time consuming and expensive to acquire and deploy new sites.

Another main driver for AAS is the need to meet coverage requirements on new and higher frequency bands. This is particularly important when introducing 5G on existing site grids.

V&D: How can 5G help industrial cases of ultra-low latency applications?

Alok Kumar Sinha: URLLC, which stands for ultra-reliable low latency, will guarantee latency to be 1ms or less. Low latency is important for gadgets that, say, drive themselves, or perform prostate surgeries.

A study by Market Research Future found that the telemedicine market is expected to grow at a compound annual growth rate of 16.5% from 2017 to 2023, parallel with the emergence and roll-out of 5G. This means that faster network speeds and the quality of care will allow doctors to remotely engage with patients without the worry of network blackouts, disconnections, lag time, etc.

Low latency allows a network to be optimized for processing incredibly large amounts of data with minimal delay (or, latency). The networks need to adapt to a broad amount of changing data in real time. 5G will enable this service to function.

URLLC is one of the key enabling technologies in the fourth industrial revolution as well. In this new industrial vision, industry control is automated by deploying networks in factories. Typical industrial automation use cases requiring URLLC include factory, process and power system automation.

Another key area URLLC can empower is by bringing several technological transformations in the transportation industry, including automated driving, road safety and traffic efficiency services. These use cases will require information to be transmitted among vehicles reliably within extremely short time duration. Several applications and use cases are already under R&D, the most promising one being automated driving.

URLLC is, arguably, the most promising addition to upcoming 5G capabilities, but it will also be the most challenging to secure. URLLC requires a quality of service (QoS), totally different from mobile broadband services (eMBB). With 3GPP release 16 scheduled for final release in June 2020, it will be interesting to see the enhancements and key feature sets made ready for commercial purpose.

V&D: How crucial will be standards-setting and spectrum allocation for 5G networks? 5G has not even started in some parts of the world, though!

Alok Kumar Sinha: One needs to consider that 5G networks are likely to be heterogeneous. The 5G standardization process is complex and highly innovative. Relevant standards bodies, both regional and global, have set out timetables for their work. These timetables are significant in the development of 5G even though the industry is likely to agree working definitions of 5G ahead of standardization.

For governments and CSPs, spectrum is also an incredibly valuable asset. Companies spend, and subsequently governments are now earning, billions of dollars to get access to particular sets of frequencies. For example, it’s common to hear about auctions for potential 5G spectrum where CSPs will bid enormous amounts of money to get access to the frequencies, they want to help build out overall coverage maps and performance capabilities.

A few other important things to understand about spectrum are that buying it is only the first step. You still need to purchase the appropriate network infrastructure equipment, tuned to transmit and receive at the correct frequencies, and install it before you can launch a 5G service.