Dimensioning of OFDM/OFDMA-based cellular networks using exponential effective SINR

The classical single-carrier cell-planning procedure is extended to multicarrier systems operating over frequency-selective channels. Extension is achieved by expressing the link outage probability in terms of the statistics of the effective signal-to-interference-plus-noise ratio (SINR). This permits evidencing the role of the number of allocated subcarriers per slot on planning. The exponential effective SINR mapping (EESM) method is adopted. A closed-form expression for the link outage probability is achieved assuming a Gaussian approximation for the derivation of the statistics of the EESM-based SINR. This formula is then used to set up a simple planning procedure requiring the evaluation of only two averages of the SINR calculated on a generic subcarrier. The effectiveness of the proposed approximation with the number of allocated subcarriers per slot is investigated. An upper bound of the link outage probability in the presence of interference is provided. For illustrative purposes, the proposed methodology is applied to the calculation of the network parameters for the typical two-cell interference scenario. It is shown that the considered approximation provides results with accuracy within 1 dB for a number of subcarriers greater than ten and for an outage performance target of 5%.