This paper presents a new cross-layer (PHY/MAC) resource allocation scheme based on Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiple Access (OFDMA) system with a multi-service (MS) and a multiuser (MU) configuration. It is about a downlink transmission chain based on the IEEE 802.16m specifications, in which the available resources (power and bandwidth) are dynamically allocated according to the system parameters such as Channel State Information (CSI), spectral efficiency, error code corrector rate, Quality of Service (QoS) requirements and services scheduling. The specificity of our system is the joint parameterization of these elements according to the total power and threshold rate constraints in order to guarantee a good trade-off between users QoS requirements and sub-carriers distribution. Simulation results show that the proposed scheme offers better performances in terms of average throughput and users satisfaction than previous resource allocation schemes.