Coordss Tutorials

Coordination of the Unlicensed Band Shared Access between LTE and WiFi Networks

As 5G is moving towards exploring new bands and access methods for wireless technologies, the coexistence of heterogeneous wireless technologies with different access methods within the same band of frequencies becomes of paramount importance. LTE in unlicensed bands (LTE-U) will play a fundamental role in maximizing the overall capacity of a cell, towards enabling novel bandwidth demanding applications (e.g. 4K video streaming) to be feasible for a wide set of users. In this tutorial, we will use real testbed infrastructure (NITOS, University of Volos, Greece) and a real LTE-U setup in order to outline the importance of coordination between heterogeneous technologies, such as LTE and WiFi. The attendees will be guided to use the testbed resources via automated tools and experiment using different levels of WiFi and LTE mutual interference in coordinated and uncoordinated environments when WiFi and LTE operate at the same, adjacent or distant channels. The following scenario is used in the experiment. There are eight nodes involved. Six nodes (three pairs of nodes) are WiFi stations using 2.4 GHz band. Each pair (nodes 50 and 65, 51 and 69, 57 and 62) create a separate ad-hoc network with its own ESSID. Two nodes are equipped with USRP B210 device. One of them is used for spectrum sensing with WiSER software (node 60). The other is running OpenaAirInterface eNB (node 59). Each node is connected with the CoordSS server that deals with the coordination process. The topology of the setup is shown in Fig. 1.

The experiment consists of the following steps:

1.  Nodes imaging

At the beginning, all nodes will be imaged with the hard disk image containing preinstalled OS (Ubuntu 14.04) with needed software and drivers.

Prior to imaging, the nodes have to be turned off:

Now, all the nodes, except node059, will be imaged with coordss_tutorial.ndz image:

After imaging, the imaged nodes should be turned on:

Node059 will be imaged with OAI image:

After imaging, the node should be turned on:

Now we have to check whether all nodes are up and running, using ping command

If the node is not running correctly, there will be no reply:

In this case, we have to turn off and on that specific node

If everything is ok, the output will be like this:

If all nodes are up and running, we have to copy coordination client application to each node:

Now, we are ready to run the experiment. Prior to exeperiment running, we have to delete any previous data on the server:

There are four experiments prepared, each with different scenario:

1.    There are two coordinated WiFi networks, a coordinated OAI eNB, and an uncoordinated WiFi network. At the beginning, all nodes are off. The spectrum sensing (SS) is performed. CoordSS server assigns channels to coordinated networks and again SS is performed. Uncoordinated network is turned on and SS is performed. Coordinated networks are turned off and SS is performed. CoordSS server again assigns channels to coordinated networks and turns them on. Finally, SS is performed.

Experiment source

2.    There are two coordinated WiFi networks, a coordinated OAI eNB, and an uncoordinated WiFi network. At the beginning, coordinated netwroks are off, and uncoordinated network is on. The spectrum sensing (SS) is performed. CoordSS server assigns channels to coordinated networks and again SS is performed.

Experiment source

3.    Based on scenario 1, but OAI eNB is uncoordinated.

Experiment source

4.    Based on scenario 2, but OAI eNB is uncoordinated.

Experiment source

Experiments 1, 2, 3, and 4 are executed with the following commands, respectively:

The results may be seen at the CoordSS server http://infosys1.elfak.ni.ac.rs/coordss/coordinationConsole

Also, the experiment progress may be monitored using the following command: