This is the method that we use to get cell phone service in the basement of the new Physical Sciences Building.

Both Verizon and AT&T have devices that work as tiny cell towers, which they call the “network extender” and “microcell” respectively. They cover about one or two rooms and send calls out through an internet connection, but they also require a GPS signal in order to function (this is only used for E911 services and has nothing to do with their normal operation). This makes them impossible to use in the basement as-is since they must be near a window in order to get the GPS signal.

However, after initially acquiring a GPS lock, they will only start looking for a GPS signal again when they are either power cycled or disconnected from the network. Thus, as long as they do not lose power and are “tricked” into thinking they are still on the same network, they can be moved from one place to another and still function. Here is a procedure for how to do this:

• Connect the microcell and network extender to an ethernet switch and UPS, as shown in the sketch below (make sure the UPS is charged first). The purpose of the ethernet switch is to ensure that the network ports remain powered at all times; disconnecting an ethernet cable from the devices themselves will suggest that they have been moved, and they will start searching for a GPS signal again.

• Load everything onto a cart and take it up to a room that has both a window (preferably south-facing) and an ethernet port that is on the same network as the one you ultimately plan to have the microcell/extender connected to. This is important so that the devices have the same public IP address after they are moved. Check with either Barry Robinson or Daniel Blakeley in CCMR to find out what ports are on what subnets (we are on the 231 subnet and use jack C2 in 609 Clark Hall for this part). Also make sure both devices are registered with CCMR.

• Run a cable from the ethernet switch to the wall ethernet jack and place the network extender and microcell in the window, so that they have the best view of the sky. Their lights will start flashing and changing colors. Wait until all lights on the microcell (except the “computer” light) are solid green, and all lights on the network extender are solid blue. This will take about 15-30 minutes.
  • Feel free to power cycle them as many times as you like, but not after they acquire a GPS lock!
  • If the WAN light does not stop flashing, unplug the ethernet cable from the microcell or network extender and reconnect it. If it never goes on solid, then either the network is down or the devices have not been registered with CCMR. Also, make sure the microcell has been activated online (not required for the network extender).
  • If the GPS light never goes on solid, try moving the devices closer to the window.
• Once both devices have acquired a GPS lock, carefully load everything onto the cart. Sometimes accidentally knocking one of the cables will cause them to start searching for a GPS signal again. Quickly unplug the ethernet cable from the wall, move the cart down to the desired room, and plug the ethernet switch into the relevant wall jack. The devices will wait for a certain amount of time before realizing the network has disappeared, so it is important to move quickly. Their lights might start flashing while in transit, but that is ok. Once reconnected, test each of them to make sure that they work (remember that only cell phones with numbers registered online can use the microcell). Also, make sure the microcell and network extender are positioned at least a foot apart, or else they might start interfering with each other.
• Once in the basement and reconnected, the microcell's lights will look the same as they did after acquiring the GPS lock (all solid green). The network extender's GPS light will blink red, but it will still function normally.

Note: Since the microcell and network extender take different amounts of time to acquire a GPS lock, it is a good idea to have a separate switch and UPS for each one.