MODIFIED PROPORTIONAL FAIR SCHEDULING FOR RESOURCE REUSE AND INTERFERENCE COORDINATION IN TWO-TIER LTE-ADVANCED SYSTEMS

In this paper, a two-tier Long Term Evolution-Advanced (LTE-Advanced) system where the second tier is deployed as femtocells is investigated. Although the reuse factor of one has been a generic concept to increase the data rate using orthogonal frequency division multiplexing (OFDMA) technology, it is difficult to achieve high spectral efficiency by employing this reuse of the same resource from cell to cell. In addition, high data rate with minimal transmission energy per bit is one of the significant issues to reduce overall energy consumption by mobile communications. In this paper, we address these issues using femtocells in the coverage of macrocells in LTE-Advanced systems. In line with prevailing high spectral and energy efficient network requirement, a novel resource reuse strategy is proposed that employs the reuse of resources in the tier level, i.e. femto tier. The same resource block (RB) can be reused in the femto tier as long as the interference coordination condition is satisfied. The proportional fair (PF) scheduling strategy is adopted on top of which the proposed resource reuse strategy is applied resulting Modified PF (MPF) scheduling strategy. A novel interference coordination strategy is developed and investigated in the MPF scheduler. In addition, a new mechanism called a€ macro user RB reservationa€ for the system average fairness performance improvement is also investigated. A system level resource scheduling simulator is developed, and its performance is evaluated based on a number of scenarios to demonstrate that high spectral and energy efficiencies can be achieved in the context of LTE-Advanced systems.