Providing the optimal coverage & capacity while the network is operative. For Quality of Service Coverage and Capacity problems may arise due to five causes 1. **Coverage hole:** Area where the User Equipment cannot access the network due to the low pilot signal strength. It may be caused by physical obstacles or inadequate RF planning. 2. **Weak coverage:** Pilot signal strength or SNR below the level to maintain a planned performance requirement. 3. **Pilot pollution:** High interference and energy consumption with a low cell performance due to overlapping cells. 4. **Overshoot coverage:** Due to reflections on buildings or lakes, the coverage of a cell may reach far beyond what was planned causing high interference and call drops. 5. **DL and UL channel coverage mismatch:** DL channel coverage larger than the UL channel coverage. The parameters that can be tuned to obtain the optimal coverage and capacity are the downlink transmit power, antenna tilt and antenna azimuth. “Adjusting the antenna tilt is one of the most powerful techniques to solve coverage and capacity problems in cellular networks”. #telco