Proportional Resource Allocation with Subcarrier Grouping in OFDM Wireless Systems

In practical orthogonal frequency division multiplexing (OFDM) wireless systems, such as long term evolution (LTE), the subcarriers assigned to one user in one scheduling determination always use the same modulation and coding schemes (MCS). Taking this implementation issue into consideration, multiuser resource allocation with subcarrier grouping is investigated in this paper. The resource allocation is modeled as an optimization problem, in which a set of proportional rate constraints ensures system fairness. Firstly, a preliminary subcarrier assignment is developed, and then, an optimal power allocation scheme is carried out to ensure the proportional rate constraints precisely. Furthermore, an entire iterative algorithm is proposed to utilize subcarrier as effectively as possible. Numerical results demonstrate that the proposed algorithm achieves sum-rate capacity which is close to optimum and distributes resource among users flexibly as well.