Title: Radio Resource Allocation for Multicarrier-Low Density Spreading Multiple Access,
Abstract: Multicarrier-low density spreading multiple access (MC-LDSMA) is a promising
multiple access technique that enables near optimum multiuser detection. In
MC-LDSMA, each user's symbol spread on a small set of subcarriers, and each
subcarrier is shared by multiple users. The unique structure of MC-LDSMA makes
the radio resource allocation more challenging comparing to some well-known
multiple access techniques. In this paper, we study the radio resource
allocation for single-cell MC-LDSMA system. Firstly, we consider the
single-user case, and derive the optimal power allocation and subcarriers
partitioning schemes. Then, by capitalizing on the optimal power allocation of
the Gaussian multiple access channel, we provide an optimal solution for
MC-LDSMA that maximizes the users' weighted sum-rate under relaxed constraints.
Due to the prohibitive complexity of the optimal solution, suboptimal
algorithms are proposed based on the guidelines inferred by the optimal
solution. The performance of the proposed algorithms and the effect of
subcarrier loading and spreading are evaluated through Monte Carlo simulations.
Numerical results show that the proposed algorithms significantly outperform
conventional static resource allocation, and MC-LDSMA can improve the system
performance in terms of spectral efficiency and fairness in comparison with
OFDMA.