  Broadcasting/multicasting is an efficient mechanism for multimedia
communications due to its high spectrum efficiency, which achieves
point-to-multipoint transmission on the same radio resources. To satisfy the
increasing demands for multimedia broadcast multicast service (MBMS), we
present a power domain non-orthogonal MBMS transmission scheme in a K-tier
heterogeneous network (HetNet). Firstly, the system model, usage scenarios, and
fundamentals of the presented scheme are discussed. Next, a tractable framework
is developed to analyse the performance of non-orthogonal MBMS transmission, by
using stochastic geometry. Based on this framework, the analytical expressions
for the signal-to-interference-plus-noise ratio (SINR) coverage probability,
average number of served users, and sum rate are derived. Furthermore,
synchronous non-orthogonal MBMS transmission to further improving the system
performance is also studied. The results demonstrate that non-orthogonal MBMS
transmission can achieve better performance than the conventional one, in which
non-orthogonal multirate one can fully utilize channel conditions to achieve a
significant rate gain, while non-orthogonal multi-service one can efficiently
use power resources to guarantee the quality of service (QoS) of high priority
users, and also provide services for low priority users simultaneously.
