Launching service on WCDMA networks is a great opportunity for service providers to increase ARPU, while carefully planning their investment budget for the near future according to real emerging demand for network expansion. Optimisation solutions assure that the same limited resources for the initial deployment will achieve more coverage or capacity, according to the operator`s initial plan. The idea is to do things right from the start; not to estimate and assess capacity, coverage or performance manually, but to plan it, and plan it accurately.

In WCDMA networks, initial planning is critical due to the strong interdependence between capacity, coverage and performance. The initial plan must be accurate, because it serves as the foundation for building the rest of the network.
Using regular planning and simulation tools as the basis for network optimisation can lead to a long process that omits some of the determining factors which set the target Key Performance Indicators (KPI) of the network. An automatic optimisation tool uses the simulation data as the basis for optimising the plan, to seek the antenna configuration which best achieves the capacity, coverage or performance level the planner wanted to accomplish. Planning a non- optimal 3G network may result in redundant site purchasing at an early stage and in coverage, capacity and Quality of Service (QoS) problems leading to poor initial user perception of the new services.
What is required then, is a system-wide automatic optimisation solution, which will incorporate all available inputs, such as the geographical database and traffic data with sophisticated simulation and prediction capabilities in order to propose an optimised network configuration prior to network deployment. Building an optimal network from the word go can dramatically boost a carrier`s bottom line, enabling a smoother launch and significant savings.

AUTOMATIC PLANNING AND OPTlMlSATlON
An automatic planning and optimisation process seeks to improve network KPls with the same number of sites and, better yet, to minimise the number of sites
while maintaining the same network performance level. Maximisation of the capacity of existing network infrastructure eliminates the need to invest in superfluous sites and resources to accommodate additional traffic. Enhanced performance helps to keep existing customers loyal and attracts new ones. For carriers, the increased and committed business rapidly translates into incremental net income that returns the initial investment in the short run (quick ROI) and establishes continued Success in the long run.

WHAT CAN BE OPTIMISED?
Optimisation is applied to antenna parameters such as tilt, azimuth (direction), pattern (antenna type) and height, and to service parameters (power per service), neighbour lists, scrambling code allocation and site location selection

CASE STUDY
An optimisation solution was applied to a WCDMA network plan for an urban area in Europe to test its ability to improve the coverage, capacity, and QoS levels of the network while maintaining the same number of sites as in the original manually optimised plan. Very significant improvements were achieved in both the voice and data services, without adding sites, but only by optimising the existing network configuration.

Voice improvement
Coverage 30%
Capacity 21%

Data improvement
Coverage 51%
Capacity 49%

In a second scenario, the optimisation goal was to reduce to a minimum the number of sites required to maintain the same coverage, capacity, and QoS levels of the original plan. First, the optimisation solution automatically selected sites to be eliminated. Then, remaining sites were optimised to maintain coverage, capacity and QoS levels. In this scenario, the optimisation solution was able to reduce the number of sites by 15.6%. At the same time, it was able to maintain the capacity and QoS levels, and, in fact, to improve coverage by 9%.

CONSIDER THE SAVINGS OFFERED BY THESE RESULTS:
The cost (CAPEX) of upgrading one current GSM/GPRS site to WCDMA is €124K (including equipment, infrastructure, transmission, core network overhead and site deployment).
The annual cost (OPEX) of operating each GSM site upgraded to WCDMA is €28K (including incremental electricity, transmission and maintenance costs in addition to the current GSM/GPRS costs.)
Therefore, CAPEX savings in this case study 234 sites eliminated at €124K per site €29.02 million; OPEX savings per annum 234 sites eliminated at €28K per site €8.55 million.
And this does not take into account savings resulting from increased capacity, which include increased usage (and consequently revenues). Moreover, cell site savings eliminate construction and maintenance expenditures, reduce the required number of planning engineers and save in drive testing costs.
Improved network performance and call quality also contribute significantly to the bottom line, by reducing churn, promoting greater customer loyalty and encouraging usage. Revenue gains follow as well, with churn reduction leading to more spending per customer, and additional, longer calls made due to less dropped or failed call attempts. And as customer satisfaction rises, customer care costs decline.

IN SUMMARY
An automatic network planning and optimization solution offers tremendous financial value to WCDMA network operators beginning with the initial stages of network planning. It enables the operator to reduce the number of sites that need to be deployed (and later maintained), leading to great infrastructure and manpower savings. At the same time, it achieves significant improvements in coverage, capacity and quality of service. Getting it right from the start is a good place to begin a successful business enterprise.

First published in the GSM Daily 2003, during 3GSM World Congress 2003
Credit: Mobile Communications International