%0 Journal Article
%T A Low-Complexity Resource Allocation Algorithm for MIMO-OFDMA Multicast Systems with Spectrum-Guarantee Provisioning
%A Ioannis G. Fraimis
%A Stavros A. Kotsopoulos
%J International Journal of Digital Multimedia Broadcasting
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/585267
%X We study the important problem of resource allocation for the downlink of Multiple-Input Multiple output (MIMO) Multicast Wireless Systems operating over frequency-selective channels and we propose a low-complexity but efficient resource allocation algorithm for MIMO-enabled OFDMA systems. The proposed solution guarantees a minimum spectrum share for each user while also takes advantage of the multicast transmission mode. The presence of multiple antennas in both transmitter and receiver offers spatial diversity to the system along with the frequency diversity added by the OFDMA access scheme. The computational complexity is reduced from exponential to linear and validation of the proposed solution is achieved through various simulation scenarios in comparison with other multicast and unicast reference schemes used in MIMO-OFDMA systems. Numerical results and complexity analysis demonstrate the feasibility of the proposed algorithm. 1. Introduction Future wireless systems along with voice are envisioned to provide plethora of rich multimedia services like mobile TV, video conferencing, and so forth, with various bandwidth requirements [1¨C5]. The introduction of new applications such as streaming video and up-to-date information distribution services (e.g., news, stock market, weather forecasting, etc.) has brought about the need for communication between one sender and many receivers. Communication between one transmitter and multiple receivers can be achieved by either the unicast or the multicast transmission mode [1¨C8]. Works [1¨C4] study Multimedia Broadcast Multimedia Service (MBMS) delivery to large group of users. Particularly, in [1, 2] authors conclude that a hybrid unicast-multicast delivery offers the best system resource utilization, while in [3], the case of reserved resources for multicast services is investigated and in [4] the use of multiple transmit and receive antennas is considered for multicasting, in order to achieve higher data rates. However, the aforementioned studies refer to Wideband Code Division Multiple Access (WCDMA) mobile networks and Orthogonal Frequency Division Multiple Access (OFDMA) scheme is the modulation and multiple access scheme adopted for next-generation wireless systems [5¨C17]. OFDMA is based on Orthogonal Frequency Modulation (OFDM) scheme and helps exploit multiuser diversity in frequency-selective channels, since it is very likely that some subcarriers that are in deep fade for some users are in good channel state for at least one of the other users [9, 12, 14]. Because of its superior performance over
%U http://www.hindawi.com/journals/ijdmb/2012/585267/