Scheduling and resource allocation on reduced ports in distributed antenna systems

In OFDMA-DAS systems, subcarrier assignment (SA), adaptive power allocation (PA) and distributed antenna (DA) port selection should be jointly optimized to exploit the system spectrum efficiency (SE). Existing algorithms do not limit the number of DA ports used. Actually, the system performance has a diminishing marginal effect on the gain of multiple ports due to interference among ports. Further, a receiver relying on too many ports is inefficient and infeasible in practice. Thus, we develop an adaptive algorithm under l₁ norm constraint to select a part of the DA ports, which achieves a good tradeoff between the system performance and the complexity on the receiver. Meanwhile, the scheduling and resource allocation on selected DA ports are solved along with port selection. Simulation results show that the total number of DA ports can be decreased by 20%-33%, while maintaining 96% of the system SE.