Solutions to Low Signal Level Problems in Cellular Networks

Possible solution ways can be listed as below:

• New Site Proposal
• Sector Addition
• Repeater
• Site Configuration Change (Antenna Type, height, azimuth, tilt changes)
• Loss or Attenuation Check ( Feeders, Connectors, Jumpers).

The best thing to do in case of low signal strength could be recommending new site additions. A prediction tool with correct and detailed height and clutter data supported with a reasonable propagation model could be used to identify the best locations to put new sites. If client is not eager to put new sites because of high costs to the budget or finds it unnecessary because of low demand on traffic, then appropriate repeaters could be used to repeat signals and improve the coverage. Adding repeaters always needs extra attention because they can bring extra interference load to the network. The received level in the repeater should be above -80dBm (or desired limits) so that it can be amplified and transmitted again. The mobile should not receive both the original and the repeated signals at the same area, cause signal from the repeater is always delayed and it will interfere with the original signal. A repeater should not amplify frequencies outside the wanted band.

If none of the above recommendations are accepted by the client, then cheaper and easier ways should be followed. First things to be checked would be possible attenuation on the cells. Faulty feeders–jumpers–connectors or other faulty equipment, high combiner loss, reduced EIRP, decreased output power, the orientations and types of antennas, unnecessary downtilts, existence of diversity and height of the site should be deeply investigated. Putting higher gain antennas, increasing output power, removing attenuations, changing antenna orientations towards desired area, reducing downtilts, replacing faulty equipment or usage of diversity gain could improve the coverage.

Please note, amplifiers (TMA or MHA) could be used to improve uplink or compensate the loss caused by long feeder. Be careful, because they will also amplify interfering signals and they will be received at higher level.