Smart Quality Enhancement in High Capacity Geran Networks

Smart quality enhancement (SQE) aims at improving traditional quality based power control algorithms by automatically adjusting the transmit power control decision thresholds to the prevailing traffic load conditions. During low traffic periods a high C/I threshold is required to protect calls against quality degradation caused by occasionally emerging interferers. At busy hour traffic level lower C/I decision thresholds are used to reduce the interference level for the most affected calls in the network. Applying this strategy the call is always best served. The benefit from SQE has been investigated by means of system level simulations. The simulation results show an optimum speech quality achieved by SQE over the whole range of feasible traffic load in the network. The percentage of satisfied users at low traffic load that would have been obtained with an optimum static decision threshold configured for busy hour traffic has been increased by SQE from about 93% to above 99%. Correspondingly the percentage of satisfied users at busy hour traffic load that would have been obtained with an optimum static decision threshold configured for low traffic has been improved from 90% up to 93%. Assuming an acceptable outage of 10% the quality improvement of about 3% can be traded-off against a capacity gain of about 10% to 15%. SQE is especially beneficial in network deployments providing mixed indoor and outdoor coverage