In this tutorial, we first present a comprehensive overview of the next generation wireless cellular networks and limitations in such networks. We then explain the importance of existing an effective RRM technique that overcomes the limitations of wireless cellular networks and maintain service continuity with QoS guarantees to the multimedia services users. RRM components are then discussed in terms of QoS that are classified at three different levels. Finally, we presents two case studies that integrate RRM components such as call admission control and bandwidth reservation and adaptation, to provide seamless handoffs to mobile users under hard constraints at both the connection and class levels.