Ubiquisys has been in the vanguard of the development of intelligent cells through our W-CDMA SON solutions. This includes our grid solutions where several femto/small cells collaborate in a mesh-type network semi-independently of the surrounding macro network. This has allowed us to develop nearly all of the Self-Organising Network capabilities outlined in 3GPP standards well in advance of the target LTE environment. The anticipated proliferation of small cells in LTE will need the cells to interact in an intelligent way if the overall signalling loads are not to be excessive, and our existing development gives us a springboard to highly capable cells in 4G.
Let’s look a bit deeper into the world of Long Term Evolution (LTE) simulation and why it’s important…
Why develop an LTE Simulator?
We have just announced our work with CTCC on an LTE network simulator. This is even more significant than our previous W-CDMA simulations. Whilst there is no substitute for real field tests and exposure, a simulator environment is a vital adjunct to a broad development strategy.
Why is it more significant for LTE?
Development of W-CDMA femtos has been principally concerned with indoor deployments where there is good RF separation between the femto and outdoor macro/micro cells. Most pundits predict, and the capacity demands more or less dictate, that LTE will be characterised by the deployment of many small cells. These will be both indoors and out, and there will be more interactions of a more complex nature between cells than those we see in W-CDMA today.
Why not use existing LTE networks?
Whilst testing in a real RF environment is a vital part of the process, it does not provide the scope for examining a wide variety of different environments so easily. In order to conduct tests between vendors, it invariably involves multi-way agreements and IOT programs, which are extremely time consuming and costly. In addition, limited LTE spectrum has actually been allocated so far (mainly for macro usage), so not all the envisaged combinations are available. For small cells, which may be operating in a variety of different frequency bands worldwide, it will not be practical to carry out all the IOTs. Therefore simulation becomes imperative.
Why is it important that the simulator is Open Source?
By making the simulator Open Source it means that it is a common platform available to as many participants as possible, and will encourage other vendors to make use of it.
What will be simulated?
The simulator can be used for investigation of the radio environment between different vendors and different cell types. It will also provide the basis for truly intelligent cells through development of Self Organising Network (SON) techniques, which vary vendor by vendor. It can be used to test and evaluate mobility across the entire radio plane: inter-vendor, inter-frequency and inter cell-type. Resource management and scheduling is crucial in LTE and its operation will control the performance and behaviour that end users will experience. Being able to model this in advance will provide vital information to developers.
Are there any other benefits?
A simulator is constrained by its processing power rather than by the cost of deploying expensive resources. A simulator can be used to test the limits of performance in situations beyond current deployments and therefore enables future scenario planning.
If you have any questions about Long Term Evolution, LTE simulation or any of the other points raised this post, leave us a comment below and we’ll get back to you.