 service mix. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Turning User Complaints into Useful Data Increasing Capacity 40.8 Conclusion It is possible to take the troubleshooting process one step deeper, beyond cause to root cause. If a certain type of problem recurs even after it is fixed, it may be the case that there is a deeper underlying problem that needs to be resolved. For example, if we find ourselves perpetually fighting pilot pollution, then it may not be enough to adjust an- tennas and add new base stations. We may need to review our planning methods or tools, asking: Is there some parameter we can change, or different approach we can take, that will reduce the pilot pollution problem overall? Perhaps we have been using three-to-one cell splitting, and we should change to four-to-one cell splitting. Or per- haps the radio propagation measurements we took were taken in winter, and summer foliage is creating interference that we did not include in our planning model. This process, called root-cause analysis, and the subsequent action, called permanent prevention, can increase system capacity and QoS a great deal, improving profitability and also improving the system's reputation with customers. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Source: CDMA CAPACITY AND QUALITY OPTIMIZATION Chapter Increasing Capacity of a Base Station We need to monitor code division multiple access (CDMA) systems closely because, un- like conventional-reuse systems, they can show few signs of trouble even when operat- ing very close to capacity limits. When our measurements of forward or reverse power levels indicate a need to improve base station capacity, we can increase a