  It is widely recognized that besides the quality of service (QoS), the energy
efficiency is also a key parameter in designing and evaluating mobile
multimedia communication systems, which has catalyzed great interest in recent
literature. In this paper, an energy efficiency model is first proposed for
multiple-input multiple-output orthogonal-frequency-division-multiplexing
(MIMO-OFDM) mobile multimedia communication systems with statistical QoS
constraints. Employing the channel matrix singular-value-decomposition (SVD)
method, all subchannels are classified by their channel characteristics.
Furthermore, the multi-channel joint optimization problem in conventional
MIMO-OFDM communication systems is transformed into a multi-target single
channel optimization problem by grouping all subchannels. Therefore, a
closed-form solution of the energy efficiency optimization is derived for
MIMO-OFDM mobile mlutimedia communication systems. As a consequence, an
energy-efficiency optimized power allocation (EEOPA) algorithm is proposed to
improve the energy efficiency of MIMO-OFDM mobile multimedia communication
systems. Simulation comparisons validate that the proposed EEOPA algorithm can
guarantee the required QoS with high energy efficiency in MIMO-OFDM mobile
multimedia communication systems.
