The Relationship between 5G, Small Cells and Neutral Hosts

With each of the four major US operators making considerable strides to commercialise 5G, the dust is now beginning to settle on the initial flurry of launches. From this, we can derive a diverse array of learnings, each of which will play an instrumental role in shaping the evolution, and even revolution, of wireless.

As 5G proliferates at a dizzying pace, so too will the cutting-edge ecosystem of use cases that it enables. For operators, such an incredible convergence of technological change introduces an unprecedented challenge, exacerbated by the continued erosion of revenues and the uphill battle to monetise connectivity.

At the forefront of this challenge is densification, and to what precise degree operators must achieve by methodically balancing investment and the projected return from it. The understanding of this is the kicker in the shift to 5G – densification is both a challenge and an opportunity for operators.

Reaching a new performance frontier with Densification

In order to fulfil an underlying compulsion to enhance network capacity, US operators are pivoting towards two complementary strategies – deployment of more spectrum in higher frequency bands and densification of the site grid.

Previously, the leap in performance from one wireless generation to the next was achieved by simply deploying more spectrum, particularly in bands with wider channel bandwidth, and by exploiting techniques such as higher modulation schemes to boost spectral efficiency. Alone, these strategies won’t cut the mustard with 5G NR.

It is here that densification of the site grid enters the equation. The gravitation towards mid-band spectrum such as that found in the Citizens Broadband Radio Service (CBRS) 3.5GHz band and mmWave (28, 39GHz, etc.) will radically change the propagation characteristics of 5G networks.

As a result of signal attenuation with this mid and high-band spectrum, mobile operators will need to deploy more macrocells and, in particular, more small cells to cover a similar geographical area as that exhibited by low-band deployments. Without stating the obvious, such densification is an incredibly CapEx intensive process for mobile operators.

However, while it is an expensive process, it is also a rewarding one. Densification of the site grid enables wireless networks to better handle peak traffic loads, in a way that is more effective than the exploitation of multi-band macrocells.

Furthermore, a dense site grid can reduce latency and required output power while dramatically enhancing uplink performance at the cell-edge. In-building signal quality is something of critical importance as a vast volume of data traffic originates from indoor environments, and densification ensures this doesn’t have to suffer with 5G.

Small cells are the answer to densification of the site grid. Operating at low power to enable aggressive spectrum re-use and in frequency bands that are closely similar to macrocell networks, they will be the driving force behind both the capacity and coverage layers of 5G.

Today’s macrocells offer poor spectral efficiency over their coverage footprint, and this is most evident at the cell edge where lower order modulation schemes must be utilised. Small cells can enhance spectral efficiency by an order of magnitude, especially with mid and high-band 5G, thanks to higher modulation schemes such as 256 QAM.

Filling a Coverage and Capacity Void with On-Demand Small Cells 

Perhaps the most lucid example of where small cells will be a fundamental component of tomorrow’s wireless networks is at temporary sites and events such as concerts, sporting venues and amusement parks. Here, there is a large number of people in a small geographical area, putting immense strain on network resources.

In fact, the above challenge is exacerbated by the reality that many such events take place in rural settings, where there is a lack of fixed fibre backhaul and patchy, low-band wireless coverage to begin with. Without pre-emptive action by mobile operators, the tidal wave of event-goers is sure to cripple the macrocell network as they try to access data services.

Small cells can make on-demand coverage and capacity simple and cost-effective to deploy for mobile operators. This marks a tremendous breakthrough from the prohibitively complex and costly distributed antenna systems (DAS) that have traditionally defined capacity and coverage enhancement at high-density events.

At stadia, for example, the combination of mid and high-band spectrum with uniformly distributed small cells makes for a potent capacity layer. In the past, many DAS implementations provided skewed network performance within different zones of stadia, something that can be attributed to sector interference issues.

Of course, the cost-effectiveness of small cells is a prevailing reason why mobile operators have been allured by them. As it becomes exponentially more difficult to monetise connectivity in a land of unlimited data, mobile operators are actively seeking solutions which will drive down the cost per bit – small cells.

The Allure of Neutral Host for Operators and Venue Owners

Combined, the emergence of small cells and shared spectrum pave the way for a new model to enhance network coverage and capacity in locations that are deemed to be not commercially viable today. This model is known as neutral host, and it involves a third-party wholesale provider offering its network assets on an open-access basis to mobile operators.

By virtue of sharing a neutral host provider’s active equipment and spectrum, whether licensed or shared, mobile operators can achieve densification of the site grid in the most cost-effective manner possible. In effect, the neutral host provider becomes a miniature mobile operator with localised coverage and capacity onto which others can roam.

To understand how a neutral host model works and why it is so compelling from a mobile operator’s perspective, we should imagine it functioning in an environment with a high density of users – think amusement parks.

In the absence of neutral host, each mobile operator that wishes to provide competent connectivity at an amusement park with small cells must deploy its own active equipment, leading to an unfavourable duplication of assets, higher deployment costs and more jarring visual pollution.

Now, apply the neutral host model to the above and there is one physical network to serve the amusement park, with each mobile operator able to join the network equally. On a separate tangent, this also enables a greater density of small cells since assets are not tied up by active equipment from multiple operators.

Conclusion: Small Cells, 5G and Neutral Hosts go hand in hand

As mobile data traffic continues to surge at an unrelenting pace, so too will the criticality of a dense site grid. This is something that only small cells can achieve, exemplified by the propagation challenges of mid-band and mmWave 5G NR.

To put it simply, the macrocell network is no longer capable of meeting end-user demand. At sporting venues and concerts, where there is an extraordinary density of mobile customers, this is even more evident. Here, marrying small cells with a neutral host model enables a new level of network performance, while being an attractive value proposition for operators.

The Alpha Wireless Multiport Small Cell antenna – AW3724 has been explicitly designed for providing high capacity and coverage in densely populated areas such as venues and amusement parks. It is a seamless solution for neutral hosts; its high port count enables multiple operators and its ultra-compact design ensures it has an extremely low visual impact, blending discreetly into its surroundings.

To find out more about Alpha Wireless, 5G and our small cell solutions for both operators and neutral hosts contact us today.