Link Budget

PROPOSAL TO

Customer Name, Location

1 Introduction

Sophisticated Network Planning tools exist today to produce accurate, detailed predictions of UMTS coverage and capacity performance. The accuracy of these tools is heavily dependant on the effort spent configuring the parameters to match the geographic location and proposed network topology. This is an extremely time consuming and complex process that can require multiple iterations.In the initial stages of a network design it can be more effective to produce quick budgetary designs that may be used to estimate initial Capital Expenditure and facilitate business modelling. A practical method of constructing a budgetary design is to determine the cell radius for sites in different environments and then use this to determine the total number of sites required for the total area to be covered. The effective cell range of a site under certain conditions can be approximated using a Link Budget calculation. Link budgets may be produced independently for the Uplink and the Downlink in order to determine the maximum allowable pathloss to meet certain specifications. Pathloss can then be substituted into a standard propagation model to estimate the cell range. Supplementary to providing an estimate of the number of sites required, for a given set of conditions, calculating the cell range will determine whether the Uplink or the Downlink is the limiting link. Comparing cell ranges for different conditions provides a quick method of analysing the effects of changing parameters such as coverage criteria or site configurations.

2 Basic UMTS Link Budget To characterise a given area the distribution of environment types (Clutter) must be determined. The telecommunications industry has adopted the following general definitions.

High Dense Urban (Indoor and Outdoor). Low Dense Urban (Indoor and Outdoor). Suburban (Indoor and Outdoor). Rural (Indoor and Outdoor).Clutter types can generally be split up into groups based on the number of subscribers per Km2 and building height and density. High dense urban clutter types have the most subs/ Km2 and a high density of building(s) in a small area. Buildings are typically tall.

Rural clutter types have the lowest subs/ Km2. Buildings are generally sparsely distributed.

Once the area to be simulated has been assigned clutter types, the environments can be defined.Figure 1 shows an example of a clutter map. The different colours represent the different clutter types.

TypeColourBldg LossSubs/Km2

(x 1,000)% of area

High Dense UrbanRed18dB1010%

Low Dense UrbanOrange16 dB525%

SuburbanYellow12 dB150%

RuralPurple 8 dB