Wireless environment evaluation method and wireless communicaton system

A wireless environment evaluation method evaluating a wireless environment of a wireless communication system, which is in an exposed situation in reception in which a normal reception rate of a prescribed wireless station decreases due to hidden wireless stations, in which a plurality of wireless stations share a same wireless channel and perform wireless communication using CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) method, the wireless environment evaluation method comprising:

• a step 1 acquiring a normal reception rate S measured in another wireless station in which a congesting situation in reception according to a number of wireless stations in transmission standby is estimated to be the same as in the prescribed wireless station, based on a transmission and reception history of wireless signals transmitted and received between the plurality of wireless stations;
• a step 3 acquiring a normal reception rate S′ of the wireless signals per a fixed channel use time from the transmission and reception history in the prescribed wireless station;
• and
• a step 4 evaluating a degree of the exposed situation in reception according to a ratio of the normal reception rate S′ to the normal reception rate S.

A wireless environment evaluation method evaluating a wireless environment of a wireless communication system, which is in an exposed situation in transmission in which a transmission opportunity acquisition rate of a prescribed wireless station decreases due to hidden wireless stations, in which a plurality of wireless stations share a same wireless channel and perform wireless communication using CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) method, the wireless environment evaluation method comprising:

• a step 1 acquiring a transmission and reception history of wireless signals transmitted and received between the plurality of wireless stations, and acquiring or estimating a number of wireless stations in transmission standby, based on the transmission and reception history;
• a step 2 calculating a transmission opportunity acquisition rate F in a congesting situation in transmission according to the number of wireless stations in transmission standby;
• a step 3 acquiring a transmission delay of the wireless signals from the transmission and reception history in the prescribed wireless station, and calculating a transmission opportunity acquisition rate F′ from the transmission delay;
• and
• a step 4 evaluating a degree of the exposed situation in transmission according to a ratio of the transmission opportunity acquisition rate F′ to the transmission opportunity acquisition rate F.

A wireless environment evaluation method evaluating a wireless environment of a wireless communication system, which is in an exposed situation in transmission in which a transmission opportunity acquisition rate of a prescribed wireless station decreases due to hidden wireless stations, in which a plurality of wireless stations share a same wireless channel and perform wireless communication using CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) method, the wireless environment evaluation method comprising:

• a step 1 acquiring a transmission opportunity acquisition rate F measured in another wireless station in which a congesting situation in transmission according to a number of wireless stations in transmission standby is estimated to be the same as in the prescribed wireless station, based on a transmission and reception history of wireless signals transmitted and received between the plurality of wireless stations;
• a step 3 acquiring a transmission delay of the wireless signals from the transmission and reception history in the prescribed wireless station, and calculating a transmission opportunity acquisition rate F′ from the transmission delay;
• and
• a step 4 evaluating a degree of the exposed situation in transmission according to a ratio of the transmission opportunity acquisition rate F′ to the transmission opportunity acquisition rate F.

A wireless communication system in which a plurality of wireless stations share a same wireless channel and perform wireless communication using CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) method, the wireless communication system evaluates one of exposed situation in reception in which a normal reception rate of a prescribed wireless station decreases due to hidden wireless stations and an exposed situation in transmission in which a transmission opportunity acquisition rate of a prescribed wireless station decreases due to hidden wireless stations, the wireless communication system comprising:

• a unit acquiring a transmission and reception history of wireless signals transmitted and received between the plurality of wireless stations;
• a unit acquiring or estimating a number of wireless stations in transmission standby based on the transmission and reception history of the wireless signals, and calculating a normal reception rate S in a congesting situation in reception and a transmission opportunity acquisition rate F in a congesting situation in transmission, according to the number of wireless stations in transmission standby;
• a unit measuring a normal reception rate S′ of the wireless signals per a fixed channel use time from the transmission and reception history in the prescribed wireless station;
• a unit acquiring a transmission delay of the wireless signals from the transmission and reception history in the prescribed wireless station and calculating a transmission opportunity acquisition rate F′ from the transmission delay;
• and
• a unit evaluating a degree of the exposed situation in reception according to a ratio of the normal reception rate S′ to the normal reception rate S, and evaluating a degree of the exposed situation in transmission according to a ratio of the transmission opportunity acquisition rate F′ to the transmission opportunity acquisition rate F.

A wireless communication system in which a plurality of wireless stations perform wireless communication using CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) method, the wireless communication system evaluates one of an exposed situation in reception in which a normal reception rate of a prescribed wireless station decreases due to hidden wireless stations and an exposed situation in transmission in which a transmission opportunity acquisition rate of the prescribed wireless station decreases due to hidden wireless stations, the wireless communication system comprising:

• a unit acquiring a transmission and reception history of wireless signals transmitted and received between the plurality of wireless stations;
• a unit, based on the transmission and reception history of the wireless signals, acquiring a normal reception rate S in another wireless station in which a congesting situation in reception according to a number of wireless stations in transmission standby is estimated to be the same as in the prescribed wireless station, and acquiring a transmission opportunity acquisition rate F in another wireless station in which the congesting situation in transmission according to the number of wireless stations in transmission standby is estimated to be the same as in the prescribed wireless station;
• a unit measuring a normal reception rate S′ of the wireless signals per a fixed channel use time from the transmission and reception history in the prescribed wireless station;
• a unit acquiring a transmission delay of the wireless signals from the transmission and reception history in the prescribed wireless station, and calculating a transmission opportunity acquisition rate F′ from the transmission delay;
• and
• a unit evaluating a degree of the exposed situation in reception according to a ratio of the normal reception rate S′ to the normal reception rate S, and evaluating a degree of the exposed situation in transmission according to a ratio of the transmission opportunity acquisition rate F′ to the transmission opportunity acquisition rate F.