Cell throughput of multicast services in OFDM-based distributed antenna systems

This paper investigates the performance of multicast services in distributed antenna systems (DAS), which is limited by the mobile user with the worst channel condition. Compared to conventional centralized antenna systems (CAS), DAS provides shorter transmission distance and thus improves channel conditions. Focusing on the effect of path loss and Rayleigh fading, the single user and ergodic throughputs for multicast services in DAS and CAS are analyzed, and verified by simulations. It is shown that given various path loss parameters, transmission powers and number of users, DAS is always preferred to CAS for multicast services. The superiority of DAS over CAS increases with path loss parameters and the number of users. Moreover, the total transmission power should be high enough to exploit the spectrum efficiency of multicast services in both DAS and CAS. Finally, to achieve the same performance, the transmission power needed in DAS is 5dB less than that in CAS, testifying DAS as a power efficient cellular structure.