Delay-Limited Capacity for Broadcast Channels

In this paper, we consider an OFDM downlink situation, where the information is sent from only one transmitter to several receivers. For such a scenario the delay-limited capacity is investigated. We show that the delay-limited capacity is equal to zero when one Rayleigh channel is assigned to each user, and that it is greater than zero in case of the broadcast model where n users share n independent channels simultaneously. Furthermore, the case of more than one channel per user is considered. For an OFDM situation with many channels, it turns out that sharing all channels by all users outperforms the exclusive assignment of channels to individual users. However, the shared channel use is worse in case of very few channels.