Evolved Multimedia Broadcast Multicast Service in LTE along with Cognitive Radio on TV Bands

摘要

Evolved Multimedia Broadcast Multicast Service (eMBMS) is one technique in Long Term Evolution (LTE) that provides a broadcast bearer to deliver video content and file delivery to an unlimited number of users. This bearer makes use of multiple cell sites to build a "single frequency network" (SFN) zone with identical downlink transmission over part of the LTE Orthogonal Frequency Division Multiplexing (OFDM) waveform. The main data demand is INTERNET, DVB along with Cellular Broadcasting at higher speeds. The resulting signal is combined at the user equipment's antenna in such a way that what is normally a neighboring cell site contributing interference becomes the source of a useful signal, thus improving the overall information signal to interference ratio, as well as spectral efficiency. In this paper, eMBMS technology and architecture are presented along with estimates of achieved performance and the impact on radio network engineering. We conclude that while eMBMS may not be an efficient solution to offer nationwide contiguous services throughout a mobile network, it may be efficiently used across an entire metropolitan area and the surrounding "capacity limited" rural areas when using a low radio band such as 700 MHz or 800 MHz, offering an impressive spectral efficiency of 1.5 b/s/Hz.