Spectrum efficiency: Delivering for 5G
Big picture thinking
Before we look at the physical hardware element of the network, let’s first take a look at what we are aiming to achieve. We have to look at industry developments as a whole and then see how equipment needs to adapt both to enable spectrum efficiency in its own right, and to support other areas where efficiency gains can be made. This may mean working together with software developments to deliver equipment that supports new virtual technologies that enable network optimization, or it may mean looking at how operator business models are changing and ensuring there are solutions available to support these changes.
As the landscape currently sits, there are five key areas where big industry trends should guide equipment manufacturers as they seek to help operators address some of the challenges of spectrum efficiency.
Self-Optimizing Networks
First up we have, Self-Optimizing Networks (SON). They aim to use artificial intelligence to adjust the elevation tilt of the antenna patterns as needed to better align with changing user densities. This can be utilized to better deal with things such as morning/evening rush hours, vacation spots, or other events that bring more users into the area than normal. The artificial intelligence element is at a software level, but fundamentally the antennas need to be able to support SON in order to reap the efficiency benefits that it offers.
At RFS we have developed our antennas to have highly reliable Remote Electrical Tilt (RET) motors which have been designed for over 10,000 movements in anticipation of it being an integral part of a SON environment. In addition, the tilting can be set at different angles for different frequencies using a technique known as dipole-level diplexing. This allows granular optimization to further improve spectrum efficiency. By taking a tandem approach with the software aspect of SON we allow operators to easily reap the benefits.
Carrier aggregation
The next area to look at is carrier aggregation. This is a technique that allows operators to use small pieces of different spectrum holdings to create a larger data channel than would be otherwise possible. It is a key component of increasing capacity and ensuring resources are used to their full potential.
RFS offers dozens of multi-band antennas that operators can use for carrier aggregation. We have focused on building a portfolio of the most flexible and versatile equipment that can be used to support the specific needs of operators, including enabling carrier aggregation.
Small cell opportunities
In order to make the most of spectrum in dense urban environments operators need to use a network architecture that is well suited to the particular challenges of this environment. The limited range of antennas in that city environment allows operators to make the most of higher frequencies such as C-band, CBRS and LAA. By tapping into such a spectrum that is perfect for use in cities, operators can increase capacity in a very efficient way.
For us at RFS this has meant ensuring our small cell antennas are capable of supporting those additional frequency bands helping to drive this particular efficiency for our customers.
Beam forming
Beam forming has been heralded as a key piece in the 5G puzzle as it will enable more concentrated use of spectrum and in turn enable operators to use spectrum resources as efficiently as possible. The benefits include additional precision, minimizing of interference and lower path loss, all contributing to the spectrum efficiency that operators are chasing.
From an RFS perspective, we have developed TDD beamforming antennas that offer a higher gain when compared to a MIMO antenna due to the narrow beam. The result for operators is an effective tool for increasing efficiency and EIRP.
Massive MIMO antennas
The final aspect for operators is using Massive MIMO antennas to further optimize the efficiencies we have already explored – combining the scanning ability of the TDD beamformer with the elevation tilt flexibility of a SON system. The dozens of independent radios integrated with the antenna allow for even higher levels of gain and EIRP to be focused exactly where the user is located.
At RFS we partner with OEMs to make the passive portions of mMIMO antennas. We focus on delivering antennas that pack maximum functionality into the smallest space possible to again offer antennas that are designed with real world challenges in mind and built to deliver a solution.
Conclusion
For operators the increased demand for spectrum leaves them with three choices; improve the efficiency of the spectrum they own, purchase more spectrum at very expensive government auctions, or fall behind their competition. It is clear to see that maximizing spectrum efficiency is the clear choice which leaves the question of how to tackle this.
As we have seen there is a real benefit of industry-wide collaboration to ensure operators are able to make the spectrum efficiency gains that are essential to meet the current and growing future needs of users. For equipment designers, understanding the latest industry developments and developing solutions that not only enable those developments but build on them will be key to ensuring mobile networks are capable of delivering the growth that is needed.
