Key Management for UMTS MBMS

3GPP 33.246 proposes Key Management Mechanism (KMM) to distribute security keys for Universal Mobile Telecommunications System (UNITS) Multimedia Broadcast and Multicast Service (MBMS). KMM introduces extra communication overhead to UNITS. The previous study, Key-Tree Scheme (KTS), resolves this issue for the IP multicast network. However, this scheme may not be so efficient while applied in UNITS MBMS due to lots of storage space and heavy multicast traffic introduced, which may decrease the QoS of UNITS MBMS. In this paper, we propose a more efficient scheme, Hash Function Scheme (HFS), to release both storage and communication overhead for KMM in UNITS MBMS. We first modify the KTS applied in the UNITS MBMS and then detail the execution of HITS, which is proven to be correct. We conduct an analytical model and simulation experiments to compare the performance between the UNITS KMM with KTS and with HITS. Our study shows that the proposed HFS can reduce both communication and storage overhead without damaging QoS of UNITS MBMS.