An operation method of a first communication node in a communication network identifies a number of second communication nodes receiving messages in a first reception mode and a number of third communication nodes receiving messages in a second reception mode. A transmission mode is determined for transmitting a wireless access in vehicular environments service advertisement (WSA) message based on the identified numbers. A transmission period is then determined for transmitting the WSA message based on the transmission mode. The WSA message is transmitted based on the transmission mode and the transmission period. A protocol used for the first reception mode is different from a protocol used for the second reception mode.