Overture supports all aspects of RF planning for LTE, from finding the right site locations to physical parameter planning (azimuth, mechanical tilt, etc...), right through to electronic parameter planning (electrical tilt, channels, cell identities) and operational network optimization.

Network performance can be visualized geographically with flexible maps and analyzed in detail using accurate statistics.

Optional modules can be added to Overture that accelerate the cell planning process through automatic optimization.

RF Planning

Like all wireless technologies, LTE's performance relies on the quality of the signals in the network. Overture uses a flexible network model and powerful signal prediction engine (Presto) to simulate network performance.

Coverage Analysis

Overture lets you visualize signal strength and quality in your network quickly and accurately. For example, here is the signal levels from a single sector taking account of frequency, terrain undulations, and antenna pattern losses:

Signals from multiple sectors can be combined to produce a picture of inteference within the network, as shown here:

Red areas are those with high signal quality and blue areas are those with low signal quality. Interference comes from background noise and other sector signals.

When calculating interference, Overture considers channel bandwidth, receiver noise figures, cell loadings, and channel assignments (including any complex channel overlaps). The interference model can be modified to consider clashes on any multiple-access parameter (such as LTE cell indentity) to assist in resource planning.

Coding Scheme Availability

LTE adapts the coding scheme it uses on a per-user basis, and higher signal quality means more efficient coding schemes can be used. Overture maps the standard coding scheme thresholds for easy visualization as follows (red shows areas where 64QAM is available, green 16QAM, and blue QPSK):

The coding schemes can also be used to categorize statistics. The following table shows coverage statistics for population and area broken down by coding scheme:

Physical Layer Cell Identity

In the LTE air interface, Physical Layer Cell Identity (PCI or CellID) is used for cell identification and channel synchronization and is divided into two parts:

• Physical Layer Cell Group (N1CellID)
• Physical Layer Identity (N2CellID)

N1CellID defines what group the cell belongs to and has a range [0, 167]. The N2CellID defines the identity and has a range [0, 2] (this is sometimes refered to as "physical layer cell ID sector"). CellID is calculated as 3 × N1CellID + N2CellID, which implies 504 possible values. See the standard (3GPP TS 36.211 version 8.9.0 Release 8 section 6.11) for a more detailed description.

Note that the N1CellID and N2CellID values are also used to seed the Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS).

Overture encapsulates N1CellID, N2CellID, CellID as Flags with appropriate ranges. This allows for easy manual adjustment and visualization of values.

Here are the flags as seen in the Radio Property Editor and the Radio Table:

Note that the CellID is calculated implicitly from the N1CellID and N2CellID flags.

Here is an example of a sector where the CellID is being used as a label:

As well as easy editing of parameters, Overture offers detailed analysis of resource reuse and Overlap. Here is an example of a signal quality map where two nearby sectors are sharing a CellID (in this case, CellID 212):

The red areas show high signal quality and the blue areas show poor signal quality. The problem sectors can quickly be identified using the resource reusue analysis shown below:

The combination of these analyses make it easy to diagnose network problems on the desktop before or after deployment.

Automation

The planning and optimization process can be automated using optional modules for Site Planner and Parameter Optimization. The same parameters, settings, and statistics that the engineer uses for manual planning are seamlessly supported by the optimization algorithms, allowing the user to access the power of automation without sacrificing the visibility and control that manual planning allows.

The Site Planner Module allows the user to find optimal site locations in a greenfield area or operational network. It can be configured to use simple link budget targets or complex quality-based statistics.

The Parameter Optimization Module automatically adjusts parameters to improve the same KPI statistics used in manual planning. All parameters can be adjusted including azimuth, mechanical & electrical downtilt, antenna model, cell height, channel, and CellID. See this tutorial for more information.