On Uplink Interference Management for OFDMA Networks

The next generation of wireless networks (4G) will use OFDMA (orthogonal frequency division multiple access) on the reverse link. In OFDMA, the reverse link resources assigned to a user are called tiles each of which consists of a subset of consecutive subcarriers. Since at most one user is assigned to each of these tiles then reverse link transmissions within a sector are orthogonal. However, the transmission is affected by intercell interference since users in adjacent sectors may also have been assigned to the same tile. If those users in the adjacent sectors transmitted with high power then the intercell interference may severely limit the SINR achieved by the user. Therefore user transmission powers must be carefully managed to avoid excessive intercell interference. In this paper we formulate and investigate this optimization problem. Numerical examples are used to illustrate our conclusions.