In this paper, a study on finding an appropriate helper node that can help increase effective frame transmission rate for cooperative communications at ad hoc networks is carried out. Those researches from reference use the reactive helper node selection mechanism which starts its role after exchanging RTS and CTS frames between source and destination nodes, and are implemented into our simulator for performance comparison. System throughput and average channel access delay are used for performance measures and all communicating nodes are assumed to move independently within the communication range. It is anticipated that this research result can be used as basic information for designing a new efficient helper node selection scheme.