  With the quick proliferation of extended reality (XR) services, the mobile
communications networks are faced with gigantic challenges to meet the
diversified and challenging service requirements. A tight coordination or even
convergence of applications and mobile networks is highly motivated. In this
paper, a multi-domain (e.g. application layer, transport layer, the core
network, radio access network, user equipment) coordination scheme is first
proposed, which facilitates a tight coordination between applications and
networks based on the current 5G networks. Toward the convergence of
applications and networks, a network architectures with cross-domain joint
processing capability is further proposed for 6G mobile communications and
beyond. Both designs are able to provide more accurate information of the
quality of experience (QoE) and quality of service (QoS), thus paving the path
for the joint optimization of applications and networks. The benefits of the
QoE assisted scheduling are further investigated via simulations. A new
QoE-oriented fairness metric is further proposed, which is capable of ensuring
better fairness when different services are scheduled. Future research
directions and their standardization impacts are also identified. Toward
optimized end-to-end service provision, the paradigm shift from loosely coupled
to converged design of applications and wireless communication networks is
indispensable.
