Pilares

This section covers the following topics:

• "Calculating Microwave Link Profiles" on page 183

• "Stopping Microwave Link Profile Calculation" on page 183

• "Setting the Storage Location of Microwave Link Profiles" on page 183

4.3.1 Calculating Microwave Link Profiles

When you are working on microwave links, Atoll automatically calculates non-existent and invalid link profile data. This can take a lot of time if the network covers a wide area. Consequently, you can calculate microwave link profiles separately, when you have more time and computer resources available. In multi-user environments, the administrator is responsible for shared microwave link profiles and can calculate them on a central Atoll document. Users can then base calculations on the latest shared profile data.

When you calculate microwave links, Atoll calculates only the non-existent and invalid profiles that intersect the rectangle containing the computation zone, whether or not the computation zone is visible. When you manually calculate the micro-wave link profiles as described in this section, Atoll does not take the computation zone into consideration; it calculates all non-existent and profiles of active and filtered microwave links.

To calculate microwave link profiles:

1. Select the Network explorer.

2. Right-click the Microwave Radio Links folder. The context menu appears.

3. Select Calculations > Profile Extraction from the context menu. Atoll calculates all non-existent and invalid profiles of active and filtered microwave links.

You can calculate the non-existent and invalid path loss matrices for all links, for a single link, or for a defined group of links, by expanding the Microwave Radio Links folder right-clicking either the single link or the defined group of links and selecting Calculations > Profile Extraction from the context menu.

4.3.2 Stopping Microwave Link Profile Calculation

Depending on the number of microwave links, it can take a long time and a lot of computer resources to calculate all profiles.

If necessary, you can stop calculation at any point.

To stop calculations:

• Click the Stop Calculations button ( ) in the toolbar. Atoll immediately stops all ongoing calculations. The results of calculations that have already been completed, however, will be saved.

4.3.3 Setting the Storage Location of Microwave Link Profiles

Microwave link profile data is stored in a folder with a ".profiles" suffix, located in the same directory as the Atoll document.

You can also update geoclimatic parameters for all or for a defined group of microwave links using the Microwave links table which contains geoclimatic parameters. In the Micro-wave links table, select the column of the parameter you want to recalculate or a selection of cells for this parameter and select Calculate from the context menu. A dialog box appears in which you can set the calculation options. For information on the parameters, see "Microwave Link Parameters" on page 175.

However, in a multi-user environment where several users are working on the same radio-planning document, you can centralise the profile data in a shared directory. In this cas, an administrator is responsible for calculating the microwave link profiles of the entire project and saving them in an external folder accessible to all users. This folder is read only and shared by all users. When users change their microwave link data and recalculate profiles, the changes to those profiles are stored locally and the shared profile data is not modified. In other words, users can read the information from the shared profiles but any changes they make are stored locally.

Centralised microwave link profiles are recalculated by the administrator on a regular basis (as described in "Calculating Microwave Link Profiles" on page 183) and take into consideration the changes that were uploaded to the central database by the users. For more information on working in a multi-user environment, see the Administrator Manual.

To set the storage location of the path loss matrices:

1. Select the Network explorer.

2. Right-click the Microwave Radio Links folder and select Calculations > Properties from the context menu. The Micro-wave Radio Links Properties window opens.

3. On the Profile Directory tab, you can set the location for your private and shared profile data:

• Private Directory: Click "..." to specify the location where you store the microwave link profile data that you gen-erate or, if you are loading profile data from a shared location, where you store your changes to shared path loss matrices.

• Shared Directory: If you are working in a multi-user Atoll environment with shared profiles, click "..." to specify the location of the shared directory that is accessible to all users. Any changes you make will not be saved to this directory; they will be saved in the location indicated in Private Directory.

4. Click OK.

Chapter 5

Backhaul Networks

This chapter provides information on using Atoll to design, analyse, and optimise a microwave link network.

This chapter covers the following topics:

• "Designing a Backhaul Network" on page 187

• "Planning and Optimising Microwave Sites" on page 188

• "Creating Links" on page 197

• "Analysing the Path Profile" on page 217

• "Analysing Microwave Link Reliability" on page 227

• "Studying Reflection" on page 236

• "Planning Microwave Link Channels" on page 244

• "Analysing Interference" on page 253

• "Exporting Custom Reports" on page 266

• "Advanced Configuration" on page 268

5 Backhaul Networks

The backhaul network is the critical link that carries the traffic between the individual cellular base stations and the core network. A physical backhaul network comprises the following assets:

• Sites, which are the extremities of links are usually shared with cellular base stations.

• Microwave links, which are defined by their radio and equipment characteristics.

• Other transmission links, are typically either fibre-optic links or leased lines.

Backhaul links must satisfy the quality and availability requirements that are set by the operator. Each link is assessed in terms of robustness, i.e., the data transmission should undergo the least possible errors, the link should suffer the least number of failures (usually measured per year) and the duration of these failures should also be as short as possible. All these criteria are described in detail in the ITU standards and recommendations.

To help you satisfy these requirements, the Atoll backhaul module enables you to plan, design, and analyse backhaul networks and to set in-depth quality and availability targets for the network, either in standalone backhaul projects or as part of larger 2G, 3G, and 4G mobile network projects. Atoll models simple, multi-hop, and point to multipoint links within a back-haul network. It can determine link budgets and carry out end-to-end reliability analyses, interference analyses, and frequency planning.

In addition to the physical layer, Atoll provides a logical layer, which is a model designed specifically for backhaul capacity planning. For more information, see Chapter 6: Backhaul Capacity Planning.