  This paper is concerned with slicing a radio access network (RAN) for
simultaneously serving two typical 5G and beyond use cases, i.e., enhanced
mobile broadband (eMBB) and ultra-reliable and low latency communications
(URLLC). Although many researches have been conducted to tackle this issue, few
of them have considered the impact of bursty URLLC. The bursty characteristic
of URLLC traffic may significantly increase the difficulty of RAN slicing on
the aspect of ensuring a ultra-low packet blocking probability. To reduce the
packet blocking probability, we re-visit the structure of physical resource
blocks (PRBs) orchestrated for bursty URLLC traffic in the time-frequency plane
based on our theoretical results. Meanwhile, we formulate the problem of
slicing a RAN enabling coordinated multi-point (CoMP) transmissions for
multicast eMBB and bursty URLLC service multiplexing as a multi-timescale
optimization problem. The goal of this problem is to maximize multicast eMBB
and bursty URLLC slice utilities, subject to physical resource constraints. To
mitigate this thorny multi-timescale problem, we transform it into multiple
single timescale problems by exploring the fundamental principle of a sample
average approximation (SAA) technique. Next, an iterative algorithm with
provable performance guarantees is developed to obtain solutions to these
single timescale problems and aggregate the obtained solutions into those of
the multi-timescale problem. We also design a prototype for the CoMP-enabled
RAN slicing system incorporating with multicast eMBB and bursty URLLC traffic
and compare the proposed iterative algorithm with the state-of-the-art
algorithm to verify the effectiveness of the algorithm.
