Wireless communication method and apparatus
A wireless communication method and apparatus that produce only a small amount of transmission delay even when carrier sensing is performed. Intensity indication data indicating the radio wave intensity of a received wireless signal is generated. The intensity indication data is intermittently captured and retained. An average of the retained intensity indication data is calculated. If the average is less than or equal to a threshold, a wireless transmission operation is enabled. The average is calculated with a frequency according to the frequency of capturing of the intensity indication data. The average and the threshold are compared at a frequency corresponding to the frequency of calculation of the average.
1. A wireless communication method for performing wireless communication by using a wireless signal, the wireless communication method comprising:
an intensity indication data generation step of successively generating intensity indication data each indicating an instantaneous radio wave intensity value of a received wireless signal;
a first data capturing and retaining step of causing a plurality of registers to intermittently capture and retain the instantaneous radio wave intensity values indicated by each of the intensity indication data;
a first average calculation step of calculating an average of the instantaneous radio wave intensity values retained by the plurality of registers;
a comparison step of comparing said average with a threshold;
a control step of enabling a wireless transmission operation when the average is less than or equal to the threshold;
a second data capturing and retaining step of, after said first average calculation step and upon detecting by said comparison step that the average exceeds the threshold, causing one of the plurality of registers to capture and retain another instantaneous radio wave intensity value of the received wireless signal; and
a second average calculation step of, upon detecting by said comparison step that the average exceeds the threshold, re-calculating the average using the values retained by the plurality of registers after said second data capturing and retaining step, wherein
the first average calculation step includes calculating the average with a frequency corresponding to a frequency of capturing the intensity indication data by the first data capturing and retaining step, and
the comparison step includes comparing the average with the threshold at a frequency corresponding to a frequency of calculation of the average.
2. The wireless communication method according to claim 1 , wherein said first average calculation step includes calculating the average when a predetermined number of pieces of the intensity indication data have been captured by said first data capturing and retaining step.
3. The wireless communication method according to claim 1 , wherein said first data capturing and retaining step includes causing the plurality of registers to capture the intensity indication data in a time-series manner.
4. The wireless communication method according to claim 3 , wherein said first data capturing and retaining step includes causing the plurality of registers to discard, if the number of pieces of the intensity indication data retained has reached a predetermined number, one of the retained pieces of the intensity indication data each time a subsequent piece of the intensity indication data is captured.
5. The wireless communication method according to claim 1 , further comprising a strong input determination step of determining whether an intensity indicated by at least one of the pieces of intensity indication data retained by the plurality of registers is greater than a strong input threshold, wherein
said comparison step includes performing, if the intensity is determined to be greater than said strong input threshold in the strong input determination step, the wireless transmission after a lapse of a certain period since the time of the determination.
6. A wireless communication apparatus for performing wireless communication by using a wireless signal, the wireless communication apparatus comprising:
an intensity indication data generation part configured to successively generate intensity indication data each indicating an instantaneous radio wave intensity value of a received wireless signal;
a first data capturing and retaining part configured to cause a plurality of registers to intermittently capture and retain the instantaneous radio wave intensity values indicated by each of the intensity indication data;
a first average calculation part configured to calculate an average of the instantaneous radio wave intensity values retained by the plurality of registers;
a comparison part configured to compare said average with a threshold;
a control part configured to enable a wireless transmission operation when the average is less than or equal to the threshold;
a second data capturing and retaining part configured to, after the calculation by said first average calculation part and upon said comparison part determining that the average exceeds the threshold, cause one of the plurality of registers to capture and retain another instantaneous radio wave intensity value of the received wireless signal; and
a second average calculation part configured to, upon said comparison part determining that the average exceeds the threshold, re-calculate the average using the values retained by the plurality of registers after said capturing and retaining of said one register caused by said second data capturing and retaining part, wherein
the first average calculation part is configured to calculate the average with a frequency corresponding to a frequency of capturing the intensity indication data by the first data capturing and retaining part, and
the comparison part is configured to compare the average with the threshold at a frequency corresponding to a frequency of calculation of the average.
7. The wireless communication apparatus according to claim 6 , wherein the first average calculation part calculates the average when a predetermined number of pieces of the intensity indication data have been captured by operation of said first data capturing and retaining part.
8. The wireless communication apparatus according to claim 6 , wherein the plurality of registers include a shift register, and capture the intensity indication data in a time-series manner.
9. The wireless communication apparatus according to claim 8 , wherein if the number of pieces of the intensity indication data retained has reached a predetermined number, said shift register discards one of the retained pieces of the intensity indication data each time a subsequent piece of the intensity indication data is captured.
10. The wireless communication apparatus according to claim 6 , further comprising a strong input determination part for determining whether an intensity indicated by at least one of the pieces of intensity indication data retained by the plurality of registers is greater than a strong input threshold, wherein
if the intensity is determined to be greater than the strong input threshold by said strong input determination part, said control part performs the wireless transmission after a lapse of a certain period since the time of the determination.
11. A wireless communication method for performing wireless communication using a wireless signal, comprising:
an intensity indication data generation step of successively generating intensity indication data each indicating an instantaneous radio wave intensity value of a received wireless signal;
a first data capturing and retaining step of causing a plurality of registers to intermittently capture and retain the instantaneous radio wave intensity values indicated by each of the intensity indication data;
a first average calculation step of calculating an average of the instantaneous radio wave intensity values retained by the plurality of registers;
a comparison step of comparing said average with a threshold;
a control step of enabling a wireless transmission operation when the average is less than or equal to the threshold;
a second data capturing and retaining step of, after said first average calculation step and upon detecting by said comparison step that the average exceeds the threshold, causing one of the plurality of registers to capture and retain another instantaneous radio wave intensity value of the received wireless signal; and
a second average calculation step of, upon detecting by said comparison step that the average exceeds the threshold, re-calculating the average using the values retained by the plurality of registers after said second data capturing and retaining step.
12. A wireless communication apparatus for performing wireless communication using a wireless signal, comprising:
an intensity indication data generation part configured to successively generate intensity indication data each indicating an instantaneous radio wave intensity value of a received wireless signal;
a first data capturing and retaining part configured to cause a plurality of registers to intermittently capture and retain the instantaneous radio wave intensity values indicated by each of the intensity indication data;
a first average calculation part configured to calculate an average of the instantaneous radio wave intensity values retained by the plurality of registers;
a comparison part configured to compare said average with a threshold;
a control part configured to enable a wireless transmission operation when the average is less than or equal to the threshold;
a second data capturing and retaining part configured to, after the calculation by said first average calculation part and upon said comparison part determining that the average exceeds the threshold, cause one of the plurality of registers to capture and retain another instantaneous radio wave intensity value of the received wireless signal; and
a second average calculation part configured to, upon said comparison part determining that the average exceeds the threshold, re-calculate the average using the values retained by the plurality of registers after said capturing and retaining of said one register caused by said second data capturing and retaining part.
13. The wireless communication method of claim 1 , wherein only one of the plurality of registers is caused to capture and retain an instantaneous radio wave intensity value of the received wireless signal in the second data capturing and retaining step.
14. The wireless communication apparatus of claim 6 , wherein only one of the plurality of registers is caused by the second data capturing and retaining part to capture and retain an instantaneous radio wave intensity value of the received wireless signal.
15. The wireless communication method of claim 11 , wherein only one of the plurality of registers is caused to capture and retain an instantaneous radio wave intensity value of the received wireless signal in the second data capturing and retaining step.
16. The wireless communication apparatus of claim 12 , wherein only one of the plurality of registers is caused by the second data capturing and retaining part to capture and retain an instantaneous radio wave intensity value of the received wireless signal.