Antenna Choice Can Make or Break Your CBRS/3.5 GHz Network Build

Jul 29, 2021 | CBRS

The antennas you choose for your CBRS/3.5 GHz wireless network can impact performance by as much as 30%. Antennas and expertise from Alpha Wireless give you optimum performance and TCO.

The antennas you choose for your CBRS/3.5 GHz wireless network can impact performance by as much as 30%. This spectrum’s characteristics are different from other bands, and applying the practices you’ve used for other frequencies could mean lower performance than you expect.

CBRS/3.5 GHz spectrum has the potential to connect the dots for full coverage in sparsely populated areas, or even in urban areas where you need more coverage or capacity. Done right, you can now provide service in places that have struggled with connectivity. Choosing the wrong antennas could mean money spent without the targeted results.

CBRS/3.5 GHz networks are different

You have a much better chance of realizing your performance goals if you take into account the unique characteristics of 3.5 GHz spectrum. Choose antennas built to minimize the weak points and capitalize on the strong points of the spectrum. Selecting the right antenna for the location and focusing on durability in the planning phase spares you the cost and woes of early rip-and-replace.

After years of installing antennas in the 3.5 GHz spectrum globally, we have found that several factors contribute to a successful CBRS/3.5 GHz network antenna installation.

Done right, you can now provide service in places that have struggled with connectivity. Choosing the wrong antennas could mean money spent without the targeted results.

Minimize interference

In a traditional cellular band network, a single cell site can cover up to 20 square miles. It would take a considerably higher number of 3.5 GHz antennas to cover the same area. Costs grow quickly when deploying new sites. Frequency reuse is extremely important, and frequency reuse depends upon reducing or eliminating interference.

Every antenna pattern has side lobes – radiation that spreads beyond its intended pattern design. When nodes are close together as they are for 3.5 GHz networks, side lobe interference can drastically erode performance.

The key is proper engineering grounded in accurate predictive analysis. RF simulation gives the expected radiation patterns of the antenna in a particular environment. You are then able to choose the antenna most suitable for the location.

Choose an antenna that blocks side lobe interference. In an environment where interference limits performance, selecting an antenna with suppressed side lobes increases performance. In one case study, Alpha Wireless observed close to 6 dB in CINR improvement from an antenna swap, something Tier 1 operators would pay millions to a RAN vendor to achieve.

Use a narrow beamwidth

Traditional FWA network engineering logic suggests using a broad antenna pattern such as a 90 or 120-degree beamwidth to achieve coverage for the greatest area at the lowest cost. In this model, sectors are separated, or the sectors use different frequencies, and interference is minimal.

For a 3.5 GHz network, converting to a 33-degree beamwidth greatly reduces energy overlap, while requiring three more antennas. Alpha Wireless’s innovative 33-degree advanced technology antennas offer maximum efficiency and often reduce the number of antennas needed. They offer single-beam 4×4 MIMO per sector and dual-beam support of 2×2 MIMO per beam. This increases capacity while lowering costs. Learn more in our white paper.

 In one case study, Alpha Wireless observed close to 6 dB in CINR improvement from an antenna swap, something Tier 1 operators would pay millions to a RAN vendor to achieve.

Build smart

You can build an effective 3.5 GHz business case using techniques such as cell splitting, frequency reuse and sector splits. Each of these has pluses and minuses. It is important to consider all aspects of the network environment when choosing techniques such as these. Selecting the correct antenna for the location has a large impact on the network’s performance.

Imagine Communications implemented a soft split feature on their 3.5 GHz network to maximize capacity, but found that the network didn’t meet their performance targets. Imagine and Alpha Wireless collaborated to find a solution. Imagine chose the Alpha Wireless AW3711 antenna for a trial because of its azimuth-side-lobe-suppressing design. Using six AW3711 antennas in a six-sector hardware split, network performance improved by more than 15.5 percent across CPE metrics, and overall signal quality increased by 5.1 dB.

Reduce nodes and zoning hassles

All operators face the challenge of decreasing cost, increasing capacity, and delivering performance. One way to do all three is to minimize equipment cost without compromising signal quality. Some of the techniques mentioned in the previous section reduce nodes and keep costs down. But they must be done right, or they can be counterproductive, as in the issues Imagine encountered.

With advanced Alpha Wireless antenna technology and experienced guidance, you can create a network at the lowest possible TCO. We talked above about how using the right antennas increases capacity and reduces nodes. When you reduce nodes, you reduce the cost of rent, installation, maintenance, radios and antennas. In addition, you reduce rooftop load and wind resistance.

Zoning delays can cause costs to climb. Such delays are unlikely with Alpha Wireless 3.5 GHz antennas because they are built to be aesthetically pleasing as well as fall within the FCC Over-the-Air Reception Devices (OTARD) rule.

Selecting the correct antenna for the location has a large impact on the network’s performance.

Experience saves you from expensive trial and error

While 3.5 GHz spectrum and its characteristics may be new to your applications, it has been in use throughout the world for many years. For more than 15 years, Alpha Wireless has advised clients on the best antennas for these networks all over the world. Our experts have the knowledge and experience to guide you through the entire process.

We partner with you to understand your goals and work with you to choose the antennas that are best for your environment. We have been there and done that, so you don’t have to make mistakes that end up costing you in valuable customers, performance, TCO or early replacement.

Contact us today. Our experts are standing by to talk with you.

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