FIELD: physics; communication.
SUBSTANCE: invention relates to communication engineering. To achieve the result, a storage unit stores a preamble signal given in a traditional system and a preamble signal given in a MIMO system. A monitoring unit in the transmitting device detects presence of any communication device which is incompatible with the MIMO system but compatible with the traditional system. A unit for obtaining channel characteristics outputs characteristics of the radio channel between the transmitting device and the receiving device. A selection unit selects the packet format based on the monitoring result obtained from the monitoring unit. The selection unit also selects where to place LTS based on wireless channel characteristics output by the unit for obtaining channel characteristics.
EFFECT: possibility of changing the preamble format and efficiency of using a data packet.
25 cl, 16 dwg
