Requirements definition, which determines a project baseline, has a strong impact on the success of a project. However, since in-depth requirements are gradually revealed through the requirements definition process, the requirements definition is not a straight forward process and often falls into disorder. Thus project management standpoints are critical for the success of the requirements definition. In this paper, we present a framework and mechanisms of communication-centered project management, which controls the requirements definition process based on the situation of communication-oriented activities among stakeholders. In addition, we present a communication-centered project plan with a planning method. The project plan, which represents a time schedule of requirements definition activities, is made by a simulation-optimization algorithm using a stakeholder matrix showing the relations of requirements domains and relevant stakeholders. The effectiveness and the significance of communication-centered project management at the requirements definition phase are demonstrated by numerical examples.