Voice over IP Realized for the 3GPP Long Term Evolution

The paper outlines voice over IP for the 3GPP long term evolution and investigates the capacity of the service. Some important components affecting capacity are antenna diversity and an efficient radio realization, including concatenation, scheduling, and link adaptation. In the paper, high capacity is achieved by using dynamic scheduling together with receiver diversity and MIMO. However, the capacity could be even higher if not limited by the physical downlink control channel in combination with large and frequent signaling messages. Persistent scheduling in its simplest form cannot match the dynamic scheduling approach, in spite of the lower protocol overhead. This is mainly due to the lack of active link adaptation. Finally, by utilizing concatenation of voice packets over the radio substantial capacity gains are possible derived from both decreased protocol overhead and fewer transmitted signaling messages.