  Due to the explosive growth in multimedia traffic, the scalability of
video-on-demand (VoD) services becomes increasingly important. By exploiting
the potential cache ability at the client side, the performance of VoD
multicast delivery can be improved through video segment pre-caching. In this
paper, we address the performance limits of client caching enabled VoD schemes
in wireless multicast networks with asynchronous requests. Both reactive and
proactive systems are investigated. Specifically, for the reactive system where
videos are transmitted on demand, we propose a joint cache allocation and
multicast delivery scheme to minimize the average bandwidth consumption under
the zero-delay constraint. For the proactive system where videos are
periodically broadcasted, a joint design of the cache-bandwidth allocation
algorithm and the delivery mechanism is developed to minimize the average
waiting time under the total bandwidth constraint. In addition to the full
access pattern where clients view videos in their entirety, we further consider
the access patterns with random endpoints, fixed-size intervals and downloading
demand, respectively. The impacts of different access patterns on the
resource-allocation algorithm and the delivery mechanism are elaborated.
Simulation results validate the accuracy of the analytical results and also
provide useful insights in designing VoD networks with client caching.
