What is the Best Method for Adding Operators at Small Cell Sites?

OK, nobody really likes to share (I still have scars from the time I pushed my sister off the rocking horse), but it is understandable when sharing antennas at Small Cell Sites.  Sharing Antennas involves tradeoffs that reduce network performance (reduced coverage and capacity).   Especially when sharing Unlicensed Bands like CBRS and LAA.  Nonetheless this is the new reality, with “Shared Infrastructure” and “Co-Location” as new buzz words for Small Cells.

So, what is the best method for adding Operators at Small Cell Sites?

There are two basic strategies. 

Either select an antenna to best accommodate the first Operator at the Small Cell Site location and then change or modify the antenna to add additional Operators as they arrive.  (AKA “get your foot in the door at the new site” strategy).   Or, select an antenna to accommodate two or more Operators to begin with and then hope that additional Operators that arrive later can use those ports effectively (AKA “if you build it, they will come” strategy).  Both design philosophies have advantages and disadvantages.  Fortunately, Kathrein has Small Cell Antennas to accommodate either strategy.

Strategy 1

The first strategy has some variations but starts the same way:  an antenna is chosen that is the best fit for the first Operator locating at the Small Cell Site.  When (and if) the second Operator arrives, the Small Cell Site must be modified to accommodate the second Operator.  Modifying the Cell Site can be accomplished several ways, but it is easiest is to simply swap out a lower port (connector) count antenna for a higher port (connector) count antenna.  Using Kathrein Canister Antennas make this easy since Kathrein has used the same form factor for their Canister Antenna for 14 years.  Not only is the Kathrein Canister widely accepted by zoning jurisdictions for easier site acquisition, but the volume is 2.5 cubic feet allowing for a quicker deployment based on new rules by the FCC.   When an older antenna such as a Kathrein 84010555 is originally specified, it is then a simple matter to replace the Kathrein Canister Antenna with another of the same exterior dimensions, but with more connectors (Figure 1).  The key to this strategy is to select an antenna like the Kathrein Canister for the first Operator.  Fortunately, this is easy since there are many Kathrein Canister Antennas to choose from, both for the original single Operator Antenna, and then for the second (or third) Operator antenna.

Another method of adding another Operator to an existing Cell site is to add Panel Antennas below an existing Canister Antenna.  Figure 2 shows three Kathrein 2-foot Panel Antennas mounted under an existing Kathrein Canister Antenna.  The disadvantage of this approach is that additional space is needed on the existing pole, possibly exceeding equipment size limitations.  However, no pre-planning for the second Operator is needed when getting the first Operator up and running as quickly as possible at a new Small Cell Site.

Strategy 2

The second strategy is to provide unused ports that will be available for future use for additional Operators on the original Antenna used at the Small Cell Site.  This method is not as flexible, since it is necessary to know the requirements for the second Operator using the existing Small Cell Site before they arrive.  For example, Kathrein Canister Antennas come in a wide variety of variations that are designed with specific Operators in mind.   Some antennas have more Mid-band ports, but the gain may be less on some of those ports.  Some Canister Antennas have Low Band ports, but usually at the cost of more Mid- or High-Band ports.  Unlicensed Bands like CBRS or LAA may or may not be needed under the same antenna radome, since they might be better served with a lower Radiation Center.  Therefore, choosing a multiple port antenna to start with requires advance knowledge of the second (or third) Operator at the specificsite.

While planning for Small Cell Site sharing is not easy, US Operators should be glad they don’t need to go the next step with sharing ports and cables (as in Europe).  If that would happen however, Kathrein (German based) has Site Sharing Adapters for RETs and is ready for even that possibility in the future.  With any luck this method of site sharing is further in the future for the US since the possibilities for Passive Inter-Modulation and other interference are greatly increased.

Start with a Kathrein Antenna

All these strategies and alternatives described for adding additional Operators at Small Cell Sites have one thing in common – start with a Kathrein Antenna.  Preferably the well accepted Kathrein Canister, to allow for the most flexibility going forward.  To make antenna sharing as easy as possible, Kathrein offers many types of Small Cell Antennas, including many different varieties of the famous Kathrein Canister Antenna (in use since 2004).  Using Kathrein Antennas offers several a wide range of options to “share”.

Rick Veghte, Director of Sales Engineering

View Kathrein USA Solutions

Small Cell Operators figure 1
Small Cell Operators figure 2