Estimation of link-layer quality parameters in a system-level LTE simulator

The Long-Term Evolution (LTE) is the next generation of current mobile telecommunication networks. LTE has a new flat radio-network architecture and a significant increase in spectrum efficiency. In this paper a link level implementation in a system-level LTE simulator is proposed. There are two important functions at link level to increase the network capacity: Link Adaptation and Dynamic Scheduling. These functions are based on user connection quality. A physical layer abstraction is performed to predict link-layer performance with a low computational cost. In this manner, realistic OFDM (Orthogonal Frequency Division Multiplexing) channel realizations with multi-path fading propagation conditions are generated at this layer to obtain an accurately value of Signal-to-Interference Ratio (SIR) for each subcarrier. Thus, a method to aggregate SIR measurements of several OFDM subcarriers into a single scalar value is described. Finally, the previously calculated SIR is then used to estimate Block Error Rate (BLER), which is used in the Link Adaptation and Dynamic Scheduling functions.