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GPS over Fiber Solutions

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GPS Over Fiber Solutions PPT – Transcript

Hello, my name is Gary Grimes. I am the Director of Sales for RF Solutions for Optical Zonu Corporation (https://www.opticalzonu.com/).  I would like to spend a few minutes to give you a quick overview of our GPS Over Fiber solutions (OZC GPS Over Fiber) The primary product in our portfolio is our GPS Fiber Transport which is the only such product approved by all the US mobile wireless carriers (GPS Fiber Transport). The GPS signal is used as a timing reference for network sync. This could either be a direct connection to the base station radios or BBUs or it can be a connection to a grandmaster timing server at the network hub which then generates the PTP sync signal which gets sent to all the base station radios over the backhaul connection. The fiber transport is a coax cable replacement between the GPS antenna and the BBUs or e-NodeB’s. It is standard practice for the U.S. wireless carriers that, for any connection over 250 feet, you must use the fiber connection. So, distance is one issue. The other important application is for distribution. When you have many BBUs at a C-RAN hub or a lot of base station connections at a base station hotel or a neutral host DAS site, then coax becomes impractical. The fiber transport solution provides a simple way to distribute the GPS over thin fiber cable using low profile components.

This is the product – you see the fiber transmitter or antenna unit which connects to the GPS antenna.

It is available with one or two RF connections. The unit can be mounted indoors or outdoors. The base unit which is the rack mounted unit you see at the bottom, has the SMA RF connections on the rear panel. Those mounting ears can be mounted either way so the chassis can be installed in a rack either way. It is available with either 8 or 16 RF outputs. Here is a typical installation. This is a simple point-to-point deployment at, say, a DAS for a hotel and there are several sectors and a number of services. Here is the active antenna, lightning arrestor and our Antenna Unit. We are showing remote power with -48 volts so it’s getting the battery backed up power from the base station. It can also be powered locally with AC power if that is not practical. Here is the base unit which then connects to the BBUs or the e-NodeB’s at the bottom. We are showing eight outputs in this case, but it could be eight or sixteen. For a distributed GPS the product can handle the additional loss of an optical splitter. You could run the fiber from the antenna unit into a 1:2, a 1:4 or 1:8 optical split to go to multiple receivers which are then distributed at the C-RAN hub. In this case we are looking at a version with two antennas connected. A WDM internally puts both channels on a single fiber and those are distributed to all those base units you see. The base units shown have an auto redundancy feature. There is an internal RF switch which selects one path as the primary.

If there is any alarm condition it will automatically flip to the backup. The base unit is NEBS Level 3 certified so that it is permissible to install it in central office locations.

This is an example of a C-RAN hub deployment. In the picture at the lower right, you see four of the receivers have been installed in the racks. the Ericsson BBU’s have not yet been installed in this picture. They will go above and below the base units shown with just thin RF jumpers going from those SMA

ports to each of the BBUs. In the photo above that you see the 1×8 optical split and on the left you see the antennas on the roof top. This has a major advantage compared to any other solution in that it is very compact and lower cost than any other solution out there. It is the only one approved by all the carriers. It is quite simple to deploy – there is no software needed. Its simple alarms connect to the existing base station network management system and into the local DAS network management system like C-Squared. It has an easy integration without having to set up a separate SNMP or any other software.

The next solution shown was requested by the carriers to provide GPS directly to the radios at the edge of the network. For 5g especially, the small cells need to be at the edge of the network, close to the users to get the actual throughput that you expect. However, in doing so, the small cell radios can be very far from the hub which means that the PTP timing signal coming over the backhaul may have to go through maybe 10 or 12 switches, routers and repeaters before it gets to the customer premises. Each time it goes through one of those hops there are errors introduced in the sync signal.

One way to correct this would be to deploy an edge grand master timing server at the customer premises but this is not always possible. This architecture shown here would be an alternative. If you have distributed small cells at a facility, many of them are going to be located far from a window or from the rooftop where the GPS signal would be available. Our distributed fiber GPS solution here takes care of that – you can see it is a very simple implementation. The one shown here would be if the small cell were like a Nokia MBO which has a fiber backhaul. In this case, we are connecting to a single GPS antenna on the roof. We’re coming down to a optical splitter which is co-located with the router for the backhaul. We take one of the unused fibers going to each location and we route that into our compact base unit. This a 3 x 5 inch box that converts the signal back to a single GPS port. That connects to the auxiliary GPS port on the small cell. These are powered locally with an AC adaptor. The alternative to this is shown here where you’ve got to say an MBI type of small cell that has a twisted pair backhaul. In this case, we’re going to have same architecture as before but we’re running a fiber alongside the cat6 which plugs into our compact base unit. It provides a pass-through on the data but we tap the PoE+ signal to provide power to our unit. It draws very little current, so it has no impact on the small cell itself. The result is very cost effective as you are not pulling any more cable than you normally would.

Those same components can be used in a simple point-to-point connection if you are back at the hub and you need to make the fiber connection for the GPS to the grand master timing server itself. You see that these components install very easily. The antenna unit in this version has a hybrid connector with power and fiber on the same connector so only a single connection is needed. The hybrid cable connects to the base unit and then a single power injector which is a PoE++ type of power is injected at the base unit. There is the single connection to the grandmaster so once again, a very simple installation which is very low profile. (For more information, see GPS Fiber Transport Solutions.

The last item I want to mention is what we call our SkyShot GPS tester. This kit is extremely useful for

for commissioning and verifying that you have a GPS signal. This verifies you have lock independently of the small cells or BBUs that may or may not be connected yet. It is a small handheld device with battery power and an on/off switch. It comes with an adapter for charging. You simply connect a short RF jumper which comes with the kit to any of the GPS RF output ports on our transport. If you have GPS lock, then the GPS receiver chip inside will indicate that with a blinking green LED here on the unit itself. For more detail, you can plug in your laptop to the micro USB port and, with the app on this thumb drive, you get a detailed readout of all the satellites that are in the constellation that you’re picking up.

You see those bars that are color-coded. The ones that are blue are the ones that are actually part of the sync. You also get a read out of the carrier noise for each signal. Finally, you can record this session and save it as part of your commissioning document and compare it to anything later. So, for a kit that’s around a thousand dollars you get all the information you need without the need for a ten thousand dollar piece of hardware making this is extremely useful tool. (For more information, see Optical Zonu SkyShot.)

I thank you for your attention. More detail is available on all these products so please contact me or contact the company and we would be happy to help you with any questions you may have.

Thank you very much.

 

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