Conventionally, there are various rules with regard to a radio communication carried out between radio communication apparatuses. For example, an IEEE standard 802.11 rule (refer to the following non-patent document 1) that is a standard rule in a radio LAN (Local Area Network) and the like are listed.
In the rule defined by the non-patent document 1 and many communication rules, at the stage prior to the communication, a transmitting part transmits a transmission request information for requesting the transmission of a data to a receiving part, and the receiving part transmits a reception preparation completion information, which is the response of the transmission request information, to the transmitting part, and the data propagation is consequently started. Also, after the data propagation, the receiving part can acknowledge the data reception by transmitting a reception acknowledgement (which may be abbreviated as Ack) information.
Also, in a digital mobile radio communication system such as a radio LAN, a land mobile communication and the like, in order to improve a propagation speed, a multi-level orthogonal amplitude modulation method that requires a synchronous detection such as 16 QAM (Quadrature Amplitude Modulation), 64 QAM and the like is applied. In the digital mobile radio communication that involves the movement of a transmitting/receiving station and the movement of a peripheral environment, the fading in which the amplitude and phase of a reception signal are varied causes the property to be largely deteriorated. Thus, in order to apply the QAM to the mobile radio communication, an effectively compensating method for the amplitude and phase variation in the reception signal caused by the fading is required.
For this reason, the mobile radio communication employs a method, in which the transmitting part periodically inserts a known reference signal (a pilot symbol, also referred to as a pilot signal) between information symbols, and the receiving part carries out the amplitude and phase variation compensation, with the pilot symbol received from the transmitting part as a standard, in a complex base band. The technique for making the insertion interval of this pilot signal variable and carrying out the communication in the insertion interval of the pilot signal suitable for each propagation path is disclosed, for example, in the following patent document 1.
Also, this applicant files a technique that reduces a propagation time of a header added to a data and an empty time and consequently improves a data propagation efficiency, in Japanese Patent Application (JP-A 2002-199227) (since this is unpublished, this is not known, and this does not configure the conventional technique). According to this technique, for example, it is possible to continuously transmit the data, remove a non-signal block between the data (between frames), carry out the reduction in the header and the substitution into the data whose capacity is small, and reduce the header capacity, and consequently improve the throughput of the communication.
Non-Patent Document 1: IEEE standard 802.11, “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, “IEEE, Inc., New York 1997
Patent Document 1: Japanese Laid Open Patent Application (JP-A 2001-339363 (Claim 6, Paragraph 0063, 0064)
However, typically, the insertion interval of the pilot signal is fixedly defined and always constant independently of the transmission path environment between the transmitting part and the receiving part. Thus, if the insertion interval of the pilot signal is made variable, an agreement with regard to the insertion interval of this pilot signal needs to be concluded between the radio communication apparatuses where the communication is executed. However, the radio communication system in which the foregoing agreement can be actually concluded does not exist. Also, for example, in the communication rule such as the radio communication rule noted in the non-patent document 1, the communication rule in which together with the respective information of the transmission request information, the reception preparation completion information, the reception Ack information and the like, the different information can be transmitted does not exist at present.