Femtocell power control by discrimination of indoor and outdoor users

Femtocells are usually deployed in an indoor environment to provide in-building coverage enhancements. However, femtocells get to provide services for not only indoor users but also outdoor users in vicinity. Without the knowledge from the femtocell of whether the serviced users are located indoor or outdoor, the outdoor users are likely to experience low Quality of Service (QoS) due to inefficient coverage management and power control from the femtocells. To resolve such problem, this paper provides a method of discriminating indoor and outdoor users in a simplified way. Also, based on such discrimination, a downlink power control scheme is provided. Through simulations, we show that the discrimination procedure achieves 97.48% of correct determination in environment with low shadowing effect, and 89.41% of correct determination with high shadowing effects. Also based on the proposed discrimination procedure, power control exploiting such information provides a 31.96% reduction of outage probability, and a 8dB performance gain for cell-edge HUEs, compared to a power control with random discrimination.