Communication apparatus and communication method, computer program, and communication system

A communication method comprising:

• in a communication apparatus comprising one or more processors:
• transmitting a first field described based on a first communication standard having a downward compatibility as part of the training frame to a communication partner provided with a plurality of antenna elements;
• and
• transmitting a second field including a training signal for the communication partner to learn a weight of an adaptive array antenna as part of the training frame, wherein the training frame is obtained by multiplexing the training signal on a payload section of a data frame of the first field regulated by the first communication standard,
• wherein the training signal comprising unique known sequences is transmitted in a signal arrangement through a phase rotation by 90 degrees such that information is transmitted in a form in which the payload section and the training signal are orthogonal to each other.

A non-transitory computer-readable storage medium having stored thereon, a computer program having at least one code section for communication, the at least one code section being executable by a computer for causing the computer to perform steps comprising:

• in a communication apparatus operable to transmit a training frame to a communication partner provided with a plurality of antenna elements:
• generating a training frame composed of a first field described based on a first communication standard having a downward compatibility and a second field comprising a training signal for the communication partner to learn a weight of an adaptive array antenna,
• wherein the training frame is obtained by multiplexing the training signal on a payload section of a data frame of the first field regulated by the first communication standard,
• wherein the training signal comprising unique known sequences is transmitted in a signal arrangement through a phase rotation by 90 degrees such that information is transmitted in a form in which the payload section and the training signal are orthogonal to each other.

A communication system comprising:

• a first communication apparatus comprising a plurality of antenna elements, a communication unit that performs a transmission and reception processing of a wireless signal by using the plurality of antenna elements, and one or more processors operable to process data transmitted and received by the communication unit;
• and
• a plurality of second communication apparatuses that simultaneously transmit training frames comprising a training signal for learning a weight of an adaptive array antenna with regard to the plurality of antenna elements to the first communication apparatus,
• wherein each of the training frames is composed of a first field described based on a first communication standard having a downward compatibility and a second field comprising a training signal for the first communication apparatus to learn the weight of the adaptive array antenna,
• wherein each of the training frames is transmitted such that the training signal is orthogonal to a payload section of the first field,
• wherein the training signal comprising unique known sequences is transmitted in a signal arrangement through a phase rotation by 90 degrees such that information is transmitted in a form in which the payload section and the training signal are orthogonal to each other.