Lin Tian ∗ ‡, Di Pang ∗,Yubo Yang ∗, Jinglin Shi ∗, Gengfa Fang †, Eryk Dutkiewicz † ∗ Institute of Computing Technology, Chinese Academy of Science, China †Department of Physics and Engineering, Macquarie University, Sydney, NSW, Australia ‡Graduate University of Chinese Academy of Sciences, Beijing, China WCNC 2010 Leo Chiang 1

Introduction System model Subcarrier allocation for multicast services Optimal Algorithm Suboptimal Algorithm Simulation results Conclusions 2

Supporting multicast/broadcast services becomes a trend of the next-generation mobile cellular networks. MBMS (Multimedia Broadcast and Multicast Service) [1] introduced by 3GPP in Release 6 MBS (Multicast and Broadcast Service) [2] defined in IEEE802.16e 3

Unicast 4

Multicast 5

Subcarrier 1 User 1User 2User 3 20 bit10 bit 15 bit 10 bit 6

Goal improve multicast throughput QoS In this paper, we focus on the Subcarrier Allocation method for Multicast services (SA-M) to improve multicast throughput while at the same time satisfying the QoS requirements of all users. 7

K K users N N subcarriers BS MS Frequency band N User 1 K User K 8

The QoS requirement of each user is to obtain the required bit rate of the base layer, denoted as R base The total bandwidth of the wireless channel is B Hz and if we use f Hz to denote the bandwidth of each subcarrier, we obtain f = B/N 9

achievable data rate of user k at subcarrier n signal to noise ratio (SNR) of user k on subcarrier n Assuming that the power is equally distributed over all the subcarriers 10

Indication of subcarrier n allocation to user k The data rate that is assigned to subcarrier n for the multicast service group 11

Minimum data rate that user k should receive in the allocation cycle 12

Subcarrier 1 User 1User 2User 3 20 bit10 bit 15 bit k=1---1/20---3/60 k=2---1/10---6/60 k=3---1/15---4/60 10 bit 13

14

 Optimal Algorithm 15

 Optimal Algorithm 16

 Optimal Algorithm 17

 Optimal Algorithm 18

 Optimal Algorithm Subcarrier m=1 19

 Suboptimal Algorithm User 1 User 2 User CnCn 20

 Suboptimal Algorithm User 1 User 2 User CnCn 21

 Suboptimal Algorithm User 1 User 2 User 3 22

Data Rate Tracking 23

32 subcarriers Optimal algorithm using 8 subcarriers The channel is a frequency selective Rayleigh fading channel The required bit rate of the base layer is 256kbps [5]. 24

Total Data Rate vs User Number (N=8,M=3) 25

Total Data Rate vs User Number (N=32,M=5) 26

User Data Rate vs Channel Quality 27

User Data Rate vs User Number 28

We propose new subcarriers allocation methods including both optimal and suboptimal algorithms to improve the multicast throughput while at the same time guaranteeing the QoS requirements. Simulation results show that the proposed optimal and suboptimal algorithms achieve better performance in comparison to the conventional multicast transmission schemes without violating the QoS requirements of all the users 29