JP5715087B2 - Control method, radio system, and radio base station - Google Patents

Description

  The present invention relates to a technology of a radio access system in which a delay time is affected.

  As a wireless method for constructing a wireless home network, for example, as described in Non-Patent Document 1, a wireless method in a wireless local area network (LAN) system defined by the IEEE 802.11 committee is typical. is there. An access method of a MAC (Medium Access Control) layer in the wireless method is defined in the IEEE 802.11 standard. In this standard, DCF (Distributed Coordination Function) using CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance), that is, autonomous distributed access control is adopted.

  In CSMA / CA, functions of carrier sense and back-off control are implemented in order to avoid collision of radio signals. In carrier sense, a wireless terminal station attempting to transmit a wireless signal checks the usage status of the wireless channel, and waits for transmission of the wireless signal while another wireless terminal station is transmitting the wireless signal. This is a method to avoid collision. In addition, back-off control is performed by using a random number generated within a specified range without transmitting a radio signal immediately after confirming that a radio channel is not used after the radio terminal station performs carrier sense. This is a method of avoiding a collision by transmitting a radio signal after waiting for the originally generated time.

  In CSMA / CA, before transmitting a radio signal, IFS (Inter Frame Space) is defined as a minimum signal transmission interval, SIFS (Short IFS) which is a short frame interval, polling frame interval PIFS (PCF (Point Coordination Function) IFS) and DIFS (DCF IFS) which is a frame interval for distributed control are defined. When the receiving side correctly receives the data signal, an ACK (ACKnowledgement) signal is transmitted as a response signal for notifying the transmitting side of normal reception, and the transmitting side uses the highest priority SIFS from the end of the received data signal. Control to receive. Furthermore, aAirPropagationTime indicating the maximum propagation delay time between the transmission side and the reception side at the time of signal transmission is defined as the specified time other than IFS. Hereinafter, the specified time represented by the above SIFS and aAirPropagationTime is referred to as a protocol specified time.

  On the other hand, in recent years, wireless communication from wireless terminal stations, such as public hotspot services in ordinary homes, offices, stations, and airports, has been used as access lines, and the Internet is accessible via broadband lines typified by optical lines. Available environments are spreading. In particular, many recent broadband routers have a built-in wireless LAN communication function. In addition to the wireless LAN communication function, the number of models in which a Bluetooth (registered trademark) communication function is built in notebook personal computers is increasing. Using such a communication function, a wireless communication environment can be easily constructed at home or in the office. Under such circumstances, there is an increasing need to install a wireless gateway device in a home or office to support a plurality of wireless systems or to flexibly support a new wireless system.

  At present, wireless gateway devices represented by broadband routers for network connection and wireless base stations or wireless gateway devices for various wireless terminal stations used in homes and offices have been developed and developed as different devices. . Therefore, in order to receive a plurality of wireless system services at the same time, it is necessary to install a plurality of different wireless gateway devices, and the installation cost is a problem. In addition, in order to receive a new wireless system service, it was necessary to install and renew new wireless gateway devices one after another.

  As the wireless gateway system, configurations shown in Patent Document 1 and Patent Document 2 have been proposed. In the technique disclosed in Patent Document 1, the wireless gateway device has a simplified configuration including only a wireless signal reception unit, digitization of a reception signal (analog-digital conversion unit), and digital signal transmission unit. A received signal digitized by the wireless gateway device can be transmitted to a signal processing server via a network, and processing such as demodulation and decoding of the received signal can be performed. In the technique disclosed in Patent Document 2, the wireless gateway device determines a device (wireless gateway device or signal processing server) that performs signal processing based on the detected wireless method, or software signal processing used in the wireless gateway device. Can be downloaded from the program server on the network in a timely manner to rewrite the signal processing unit.

  According to the configuration using the techniques of Patent Document 1 and Patent Document 2, the software signal processing on the signal processing server side is changed to provide a plurality of wireless system services including a new wireless system. Therefore, it can be expected to solve the cost problem by installing / renewing a new wireless gateway device.

  Note that such a wireless gateway system configuration can also be used as a network that mediates a wide area network such as the Internet or a WAN (Wide Area Network). In addition, the configuration is not limited to this, and a configuration such as using a personal computer as a signal processing server or using a device such as a home gateway or a service gateway in a LAN environment typified by an office network or a home network is also possible. It is. Hereinafter, the radio access system is referred to as a flexible wireless system, and a radio base station in the flexible wireless system is referred to as a flexible radio base station.

JP 2007-166278 A JP 2009-231903 A

IEEE Std 802.11-2007 (P.256-271)

  However, in a radio access system (for example, IEEE 802.11 standard) in which a protocol stipulated time is set, the minimum reception sensitivity is satisfied, but the radio base station and the radio terminal station are located at a long distance. There is a wireless terminal station that cannot establish communication with a wireless base station because a long propagation delay time occurs and the protocol specified time (aAirpropagationTime) cannot be observed.

  Also, in the flexible wireless system, a long processing delay time occurs due to the low processing capability of the flexible wireless base station. As a result, there is a wireless terminal station that satisfies the minimum reception sensitivity but cannot establish the protocol specified time (SIFS) and cannot establish communication with the flexible wireless base station.

  By controlling (relaxing) the set protocol stipulated time, the wireless terminal station can satisfy the protocol stipulated time and can establish communication with the radio base station or the flexible radio base station. For example, the technology shown in Japanese Patent No. 3963700 describes a method for dynamically changing standard parameters of a wireless LAN.

  The means for realizing the method will be briefly described as follows. First, a standard parameter to be monitored and a threshold value for the standard parameter are determined. Next, after establishing a BSS (Basic Service Set), which is a network composed of a radio base station and a plurality of radio terminal stations, the standard parameters are monitored. If the standard parameter falls below the threshold, the constructed BSS is terminated, and the BSS is reconstructed so that the standard parameter satisfies a desired condition.

  In this patent, ATIM window, contention-free period (dot11CFPPeriod), and maximum period of contention-free period (dot11CFPMaxDuration) are listed as standard parameters. When the protocol specified time cannot be satisfied, the wireless terminal station that cannot establish communication with the wireless base station or the flexible wireless base station is reconfigured by reconstructing the BSS with the protocol specified time relaxed. It is considered that communication with the flexible radio base station can be established.

  However, when the control condition is only to satisfy the minimum reception sensitivity, the wireless terminal station with the relaxed protocol prescribed time is less than the wireless terminal station that can keep the original protocol prescribed time (before relaxation). Since the time required for communication with a station or a flexible wireless base station becomes longer, there is a problem that transmission characteristics (for example, throughput) deteriorate.

  In addition, when the BSS is reconstructed in order to relax the protocol specification time, the protocol specification time set in all the radio terminal stations under the radio base station or flexible radio base station is alleviated all at once. Therefore, the protocol specification time set in the wireless terminal station that does not need to reduce the protocol specification time is also reduced, which causes a problem that unnecessary transmission characteristics are deteriorated.

  In view of the above circumstances, an object of the present invention is to provide a technique for reducing deterioration of transmission characteristics in a system that performs wireless communication by relaxing a protocol specification time.

  One aspect of the present invention is a control method performed by a wireless system including a wireless terminal station and a wireless base station, wherein the wireless terminal station notifies the wireless base station of information necessary for calculating a throughput. The wireless base station calculates a throughput based on the information, the wireless base station calculates a reference throughput based on a transmission rate and a reference protocol specified time, and the wireless base station, Calculating a throughput degradation amount based on the throughput and the reference throughput; determining whether the radio base station can change a protocol stipulated time based on received power and the degradation amount; and If the station has the received power equal to or higher than the minimum receiving sensitivity and the deterioration amount is equal to or lower than a threshold, the protocol Changing the prescribed time and duration calculation method, the radio base station notifying the radio terminal station of the changed protocol prescribed time and duration calculation method, and the radio terminal station Reflecting the protocol specified time notified from the station and the duration calculation method to the own apparatus.

  One aspect of the present invention is the above-described control method, wherein the radio base station calculates the deterioration amount based on a distance between the radio base station and the radio terminal station.

  One aspect of the present invention is the above control method, wherein the radio base station calculates the deterioration amount based on a time required for communication between the radio base station and the radio terminal station.

  One aspect of the present invention is the above-described control method, wherein the radio base station calculates the deterioration amount based on a request protocol stipulated time calculated when a signal is received from the radio terminal station.

  One aspect of the present invention is a wireless system including a wireless terminal station and a wireless base station, wherein the wireless terminal station notifies the wireless base station of information necessary for calculating throughput, and A change unit that reflects the protocol specified time and the duration calculation method notified from the radio base station on its own device, the radio base station calculating a throughput based on the information, a transmission rate, A reference throughput calculation unit that calculates a reference throughput based on a standard protocol stipulated time, a throughput deterioration amount calculation unit that calculates a throughput deterioration amount based on the throughput and the reference throughput, and a received power and the deterioration amount A protocol specified time change determination unit for determining whether or not the protocol specified time can be changed, When the received power is equal to or higher than the minimum reception sensitivity and the deterioration amount is equal to or less than the threshold, a change unit that changes the protocol specified time and the duration calculation method, and the protocol specified time and duration after the change to the wireless terminal station And a notification unit that notifies a calculation method.

  One aspect of the present invention is a wireless base station that wirelessly communicates with a wireless terminal station, a throughput calculation unit that is notified from the wireless terminal station and calculates a throughput based on information necessary for calculating the throughput; A reference throughput calculation unit that calculates a reference throughput based on a transmission rate and a reference protocol specified time, a throughput deterioration amount calculation unit that calculates a throughput deterioration amount based on the throughput and the reference throughput, received power and the deterioration amount A protocol regulation time change determination unit that determines whether or not the protocol regulation time can be changed based on the protocol regulation time and duration calculation when the received power is equal to or higher than the minimum reception sensitivity and the deterioration amount is equal to or less than a threshold value. A change unit for changing a method, and a protocol after the change to the wireless terminal station A notification unit for notifying the constant-time and duration calculation method, a radio base station comprising a.

  According to the present invention, it is possible to reduce deterioration of transmission characteristics in a system that performs wireless communication by relaxing the protocol specification time.

1 is a block diagram of a radio access system according to a first embodiment of the present invention. It is a sequence diagram concerning the 1st embodiment of the present invention. It is a conceptual diagram regarding the change of the duration calculation method in the 1st Embodiment of this invention. It is a conceptual diagram regarding the change of SIFS. It is a block diagram of the radio | wireless access system which concerns on the 2nd Embodiment of this invention. It is a sequence diagram concerning the 2nd embodiment of the present invention. It is a block diagram of the radio | wireless access system which concerns on the 3rd Embodiment of this invention. It is a sequence diagram concerning the 3rd embodiment of the present invention. It is a block diagram of the radio | wireless access system which concerns on the 4th Embodiment of this invention. It is a sequence diagram concerning a 4th embodiment of the present invention. It is a conceptual diagram regarding the change of the duration calculation method in the 4th Embodiment of this invention.

[First Embodiment]
FIG. 1 is a block diagram of a radio access system according to the first embodiment of the present invention. As shown in FIG. 1, the radio access system according to the first embodiment of the present invention includes a radio base station 101 and a radio terminal station 102.

  In the first embodiment, as a control condition for relaxing the protocol stipulated time, in addition to the minimum reception sensitivity, a process that takes into account the throughput degradation amount at the time of control is performed, and the process is applied to each wireless terminal station 102. This is implemented as a process to reduce the protocol specification time. Hereinafter, the above-mentioned protocol pre-specified time (before relaxation) is referred to as the standard protocol pre-defined time, and when the standard protocol pre-defined time is used, communication of the data signal is completed. The throughput calculated from the time required until the reception of the response signal is completed) is referred to as a reference throughput.

  The radio base station 101 includes a communication unit (transmission unit and reception unit) 111, a throughput calculation information acquisition / calculation unit 121, a throughput calculation unit 122, a received power measurement unit 131, a transmission rate determination unit 132, a reference A throughput calculation unit 133, a throughput deterioration amount calculation unit 141, a protocol specification time change determination unit 142, a protocol specification time change unit 151, a protocol specification time change notification signal creation unit 152, a duration calculation method change unit 161, A duration calculation method change notification signal creation unit 162.

  The communication unit 111 transmits and receives signals to and from the communication unit 171 of the wireless terminal station 102. The throughput calculation information acquisition / calculation unit 121 acquires or calculates information necessary for the throughput calculation unit 122 to calculate the throughput. The throughput calculation unit 122 calculates the throughput from the information acquired or calculated by the throughput calculation information acquisition / calculation unit 121. The received power measuring unit 131 measures the received power of the received signal. The transmission rate determining unit 132 determines the transmission rate from the received power measured by the received power measuring unit 131. The reference throughput calculation unit 133 calculates the reference throughput from the transmission rate determined by the transmission rate determination unit and the reference protocol specified time.

  The throughput deterioration amount calculation unit 141 calculates a throughput deterioration amount from the throughput calculated by the throughput calculation unit 122 and the reference throughput calculated by the reference throughput calculation unit 133. The protocol specified time change determination unit 142 determines whether or not the protocol specified time can be changed from the received power measured by the received power measuring unit 131 and the throughput deterioration amount calculated by the throughput deterioration amount calculating unit 141.

  The protocol specified time change unit 151 changes the protocol specified time set in the radio base station 101 when the protocol specified time change determination unit 142 permits the change of the protocol specified time. The protocol specified time change notification signal creation unit 152 creates a signal for notifying the protocol specified time changed by the protocol specified time change unit 151 (hereinafter, protocol specified time change notification signal).

  The duration calculation method changing unit 161 changes the duration calculation method set in the radio base station 101 when the protocol specified time change determination unit 142 permits the change of the protocol specified time. The duration calculation method change notification signal creation unit 162 creates a signal that notifies the duration calculation method changed by the duration calculation method change unit 161 (hereinafter, duration calculation method change notification signal).

  The wireless terminal station 102 includes a communication unit 171, a throughput calculation information notification signal creation unit 172, and a synchronization establishment unit 173.

  The throughput calculation information notification signal creation unit 172 creates a signal (hereinafter referred to as throughput calculation information notification signal) for notifying information necessary for calculating the throughput (hereinafter referred to as throughput calculation information). The communication unit 171 transmits and receives signals to and from the communication unit 111 of the radio base station 101. The synchronization establishment unit 173 establishes time synchronization with the wireless base station 101 when receiving a notification signal (hereinafter referred to as a beacon signal) from the wireless base station.

FIG. 2 is a sequence diagram according to the first embodiment of the present invention. Processing in the radio access system according to the first embodiment of the present invention will be described with reference to the sequence diagram of FIG.
In FIG. 2, in the wireless base station 101, the communication unit 111 transmits a beacon signal to the wireless terminal station 102 (step S101).
In the wireless terminal station 102, the communication unit 171 receives the beacon signal, and the synchronization establishing unit 173 determines the wireless base station 101 to be connected based on the beacon signal (step S102), and performs time synchronization. Establish (step S103).

In the wireless terminal station 102, the communication unit 171 transmits an authentication signal to the wireless base station 101 in order to establish a connection with the wireless base station 101 (step S104).
In the radio base station 101, the communication unit 111 receives the authentication signal, and if it is in time within the standard protocol prescribed time, transmits an ACK signal corresponding to the authentication signal to the radio terminal station 102 (step S105). ).
In the wireless terminal station 102, when the ACK signal cannot be received within the reference protocol prescribed time, the communication unit 171 retransmits the authentication signal to the wireless base station 101 (step S106). When the number of retransmissions of the authentication signal exceeds the maximum number of retransmissions (step S107), the communication unit 171 sends the throughput calculation information notification signal generated by the throughput calculation information notification signal generation unit 172 to the radio base station 101. Transmit (step S108).

  In the wireless base station 101, the communication unit 111 receives the throughput calculation information notification signal from the wireless terminal station 102. Then, the throughput calculation information acquisition / calculation unit 121 acquires the throughput calculation information from the throughput calculation information notification signal (step S109). Also, the received power measuring unit 131 measures the received power of the throughput calculation information notification signal (step S110). Then, the transmission rate determining unit 132 determines the transmission rate from the received power (step S111). Subsequently, the reference throughput calculation unit 133 calculates the reference throughput from the transmission rate and the reference protocol specified time (step S112).

  In the radio base station 101, the throughput calculation unit 122 calculates the throughput from the throughput calculation information (step S113). In the first embodiment, for example, the throughput in an upper layer such as an IP (Internet Protocol) layer (throughput: data signal transmission efficiency) is the communication of the data signal size and the data signal (data signal transmission starts). And from the time required until reception of the response signal corresponding to the data signal is completed).

  In the radio base station 101, the throughput deterioration amount calculation unit 141 calculates a throughput deterioration amount from the throughput and the reference throughput (step S114). Then, the protocol specified time change determination unit 142 determines whether or not the protocol specified time can be changed from the received power and the throughput deterioration amount (step S115). Specifically, when the received power is equal to or higher than the minimum reception sensitivity and the throughput degradation amount is equal to or less than a threshold value, the change of the protocol specified time is permitted.

In the wireless base station 101, when the change of the protocol specified time is permitted, the protocol specified time changing unit 151 performs the change (step S116). Then, the protocol specified time change notification signal creating unit 152 creates a protocol specified time change notification signal for notifying the change.
Further, the duration calculation method changing unit 161 changes the duration calculation method (step S117). Then, the duration calculation method change notification signal creation unit 162 creates a duration calculation method change notification signal for notifying the change. Subsequently, the communication unit 111 transmits the protocol specified time change notification signal and the duration calculation method change notification signal to the wireless terminal station 102 (step S118).

FIG. 3 is a conceptual diagram relating to a change in the duration calculation method in the first embodiment of the present invention. FIG. 3A shows a normal response sequence that can satisfy the standard protocol definition time. FIG. 3B shows a response sequence in the case where the reference protocol specified time cannot be satisfied and the duration calculation method is changed.
As illustrated in FIG. 3, when a data signal is transmitted from the wireless terminal station 102 to the wireless base station 101, the wireless base station 101 performs reception processing on the data signal and receives the data signal. After the SIFS time has elapsed, an ACK signal is transmitted to the wireless terminal station 102. As shown in FIG. 3A, in the normal response sequence, the total frame length of the SIFS and ACK signals is set in a NAV (Network Allocation Vector) period. Other wireless terminal stations in the vicinity that are not involved in transmission and reception prohibit transmission during this NAV period.
There is a propagation delay time between the wireless terminal station 102 and the wireless base station 101. When this propagation delay time is short, as shown in FIG. 3A, the wireless terminal station 102 can receive the ACK signal from the wireless base station 101 within the NAV period T1, and satisfies the reference protocol specified time. it can.

  On the other hand, as shown in FIG. 3B, if the propagation delay time between the wireless terminal station 102 and the wireless base station 101 is long, the reference protocol specified time cannot be satisfied. In this example, the propagation delay time between the wireless terminal station 102 and the wireless base station 101 (aAirPropagationTime; in the IEEE 802.11 standard, aAirPropagationTime is defined as 1 μs or less) is [1 μs + α]. Therefore, when transmitting a data signal from the wireless terminal station 102 to the wireless base station 101, a propagation delay time of [1 μs + α] occurs, and when transmitting an ACK signal from the wireless base station 101 to the wireless terminal station 102 [ The propagation delay time of 1 μs + α] occurs. In this case, the wireless terminal station 102 cannot receive the ACK signal from the wireless base station 101 within the NAV period T1. Therefore, as shown in FIG. 3B, the NAV period is set to be extended to a period T2 obtained by adding the propagation delay time 2α to the total frame length of the SIFS and ACK signals. Thus, by extending the NAV period to T2, the wireless terminal station 102 can receive the ACK signal from the wireless base station 101 within the NAV period T2.

  In FIG. 2, in the wireless terminal station 102, the communication unit 171 receives the protocol specified time change notification signal and the duration calculation method change notification signal, and changes the protocol specified time and the duration calculation method (steps S119 and S120). And the communication part 171 transmits an authentication signal to the wireless base station 101 again (step S121).

  In the radio base station 101, the communication unit 111 receives an authentication signal. In this time, as shown in FIG. 3, because the protocol specified time is relaxed, the communication unit 111 transmits an ACK signal corresponding to the authentication signal to the wireless terminal station 102 within the protocol specified time. (Step S122).

In the wireless terminal station 102, the communication unit 171 receives the ACK signal and transmits an association signal to the wireless base station 101 (step S123).
In the radio base station 101, the communication unit 111 receives an association signal. And the communication part 111 will transmit the ACK signal corresponding to the said association signal to the radio | wireless terminal station 102, if an association signal is received (step S124).
In the wireless terminal station 102, the communication unit 171 receives the ACK signal and establishes a connection with the wireless base station 101, so that a data signal can be transmitted to the wireless base station 101 (step S125). .
In the radio base station 101, when the communication unit 111 receives the data signal, the communication unit 111 transmits an ACK signal corresponding to the data signal to the radio terminal station 102 (step S126).

  If the wireless terminal station 102 can receive the ACK signal corresponding to the first authentication signal within the standard protocol stipulated time (steps S104 to S105), the duration calculation is performed from the transmission of the throughput calculation information notification signal. It is not necessary to perform the processing (steps S108 to S122) until the ACK signal corresponding to the authentication signal to be transmitted is received after changing the method.

  As described above, the method of changing the duration calculation method according to the change of the protocol specification time has been described, but the present invention is not limited to the above. That is, in the above-described example, as shown in FIG. 3, the change process for extending the NAV period corresponding to the propagation delay time is performed, but the SIFS may be shortened corresponding to the propagation delay time.

FIG. 4 is a conceptual diagram regarding SIFS change. FIG. 4A shows a normal response sequence that can satisfy the standard protocol definition time. FIG. 4B shows a response sequence when the SIFS is changed without satisfying the standard protocol stipulated time.
As shown in FIG. 4, SIFS is the time from the reception of a data signal to the transmission of an ACK signal. In a normal response sequence, the SIFS time is set to 16 μs, for example. The sum of the frame lengths of the SIFS and ACK signals is set in the NAV period.
There is a propagation delay time between the wireless terminal station 102 and the wireless base station 101. When the propagation delay time is short, as shown in FIG. 4A, the wireless terminal station 102 can receive the ACK signal from the wireless base station 101 within the NAV period, and can satisfy the reference protocol specified time. .

  On the other hand, as shown in FIG. 4B, if the propagation delay time between the wireless terminal station 102 and the wireless base station 101 is long, the reference protocol specified time cannot be satisfied. In this example, the propagation delay time (aAirPropagationTime; in the IEEE 802.11 standard, aAirPropagationTime is defined as 1 μs or less) between the wireless terminal station 102 and the wireless base station 101 is [1 μs + α]. Therefore, when transmitting a data signal from the wireless terminal station 102 to the wireless base station 101, a propagation delay time of [1 μs + α] occurs, and when transmitting an ACK signal from the wireless base station 101 to the wireless terminal station 102 [ The propagation delay time of 1 μs + α] occurs. In this case, the wireless terminal station 102 cannot receive the ACK signal from the wireless base station 101 within the NAV period. Therefore, as shown in FIG. 4B, the SIFS is shortened, and the time from when the wireless base station 101 receives the data signal from the wireless terminal station 102 to when the ACK signal is transmitted to the wireless terminal station 102 is reduced. shorten. That is, in this example, SIFS is shortened by 2α and changed to [16 μs−2α]. Thus, by shortening the SIFS, the wireless terminal station 102 can receive the ACK signal from the wireless base station 101 within the NAV period.

  In this case, it is necessary to determine whether or not SIFS can be shortened between the radio base station 101 and the radio terminal station 102. However, the radio base station 101 and the radio terminal station 102 do not deteriorate throughput. It is possible to establish communication between them.

  Further, a method for changing the duration calculation method and a method for shortening SIFS may be used in combination. That is, if the distance between the radio base station 101 and the radio terminal station 102 is not so far and the SIFS is shortened and the shortening is possible, the SIFS is shortened and the radio base station 101 and the radio terminal If the distance between the station 102 and the station 102 is a long distance, and the amount of shortening of the SIFS is large and the shortening is not possible, the duration calculation method may be changed.

As described above, in the first embodiment of the present invention, in addition to the reception power being equal to or higher than the minimum reception sensitivity, the throughput degradation amount is calculated, and when the calculated throughput degradation amount is equal to or less than the threshold, The change of regulation time is permitted. As a result, since the radio base station 101 and the radio terminal station 102 are located at a long distance, even if the propagation delay time cannot satisfy the standard protocol specification time, the throughput degradation amount is kept below a certain value. Meanwhile, communication between the wireless base station 101 and the wireless terminal station 102 can be established.
In addition, since the above series of processing is individually performed for each wireless terminal station 102, the protocol specified time of the wireless terminal station 102 that can satisfy the reference protocol specified time without changing the propagation delay time is not changed. Therefore, it is possible to prevent the deterioration of the throughput in the wireless terminal station other than the wireless terminal station 102 that relaxes the protocol specification time.

[Second Embodiment]
FIG. 5 is a block diagram of a radio access system according to the second embodiment of the present invention. As shown in FIG. 5, the system according to the second embodiment of the present invention includes a radio base station 201 and a radio terminal station 202.

  The radio base station 201 includes a location information acquisition unit 210, a communication unit 211, a transmission delay time calculation unit 221, a throughput calculation unit 222, a received power measurement unit 231, a transmission rate determination unit 232, and a reference throughput calculation unit. 233, throughput deterioration amount calculation unit 241, protocol specified time change determination unit 242, protocol specified time change unit 251, protocol specified time change notification signal creation unit 252, duration calculation method change unit 261, duration calculation method A change notification signal generation unit 262.

  The wireless terminal station 202 includes a location information acquisition unit 270, a communication unit 271, a location information notification signal creation unit 272, and a synchronization establishment unit 273.

  In the second embodiment, the transmission delay time is calculated based on the distance between the wireless base station 201 and the wireless terminal station 202, and the throughput deterioration amount is calculated. The basic configuration of the second embodiment is the same as that of the first embodiment.

In the radio access system according to the second embodiment, the radio base station 201 is further provided with a position information acquisition unit 210 and a transmission delay time calculation unit 221 as compared with the first embodiment.
When the position information acquisition unit 210 receives a signal for notifying position information from the wireless terminal station 202 (hereinafter, a position information notification signal), the position information acquisition unit 210 acquires the position information of the wireless terminal station 202. Further, the location information acquisition unit 210 acquires location information of the radio base station 201. As a method of acquiring the position information of the wireless base station 201, for example, it is conceivable to use GPS (Global Positioning System). The transmission delay time calculation unit 221 calculates the distance between the radio base station 201 and the radio terminal station 202 from the location information of the radio base station 201 and the location information of the radio terminal station 202 acquired by the location information acquisition unit 210. The transmission delay time is calculated from the calculated distance and the transmission rate determined by the transmission rate determination unit 232. The throughput calculator 222 calculates the throughput from the transmission delay time calculated by the transmission delay time calculator 221. About another structure, it is the same as that of the above-mentioned 1st Embodiment.

Further, in the wireless access system according to the second embodiment, the wireless terminal station 202 is further provided with a location information acquisition unit 270 and a location information notification signal creation unit 272 as compared with the first embodiment. .
The location information acquisition unit 270 acquires location information of the wireless terminal station 202. As a method for acquiring the position information, for example, a method using GPS is conceivable. The position information notification signal creation unit 272 creates a position information notification signal. About another structure, it is the same as that of the above-mentioned 1st Embodiment.

FIG. 6 is a sequence diagram according to the second embodiment of the present invention. Processing in the wireless access system according to the second embodiment of the present invention will be described with reference to the sequence diagram of FIG.
In FIG. 6, in the radio base station 201, the position information acquisition unit 210 acquires its own position information (step S200a). In the wireless terminal station 202, the position information acquisition unit 270 acquires its own position information (step S200b).
In the wireless base station 201, the communication unit 211 transmits a beacon signal to the wireless terminal station 202 (step S201).
In the wireless terminal station 202, the communication unit 271 receives the beacon signal, and the synchronization establishment unit 273 determines the wireless base station 201 to be connected based on the beacon signal (step S202), and performs time synchronization. Establish (step S203).

In the wireless terminal station 202, the communication unit 271 transmits an authentication signal to the wireless base station 201 in order to establish a connection with the wireless base station 201 (step S204).
In the wireless base station 201, the communication unit 211 receives the authentication signal, and when it is in time within the standard protocol prescribed time, transmits an ACK signal corresponding to the authentication signal to the wireless terminal station 202 (step S205). ).
In the wireless terminal station 202, when the ACK signal cannot be received within the reference protocol prescribed time, the communication unit 271 retransmits the authentication signal to the wireless base station 201 (step S206). When the number of retransmissions of the authentication signal exceeds the maximum number of retransmissions (step S207), the communication unit 271 transmits the location information notification signal created by the location information notification signal creation unit 272 to the radio base station 201 (step S207). S208).

  In the wireless base station 201, the communication unit 211 receives a position information notification signal from the wireless terminal station 202. Then, the position information acquisition unit 210 acquires the position information of the wireless terminal station 202 from the position information notification signal (step S209). Also, the received power measuring unit 231 measures the received power of the position information notification signal (step S210). Then, the transmission rate determining unit 232 determines a transmission rate from the received power (step S211). Subsequently, the reference throughput calculation unit 233 calculates the reference throughput from the transmission rate and the reference protocol specified time (step S212).

  In the radio base station 201, the transmission delay time calculation unit 221 calculates the distance between the radio base station 201 and the radio terminal station 202 from the location information of the radio base station 201 and the location information of the radio terminal station 202. Then, a transmission delay time is calculated from the calculated distance and the determined transmission rate (step S213a). Then, the throughput calculator 222 calculates the throughput from the transmission delay time (step S213b).

  In the radio base station 201, the throughput deterioration amount calculation unit 241 calculates a throughput deterioration amount from the throughput and the reference throughput (step S214). Then, the protocol specified time change determination unit 242 determines whether or not the protocol specified time can be changed from the received power and the throughput degradation amount (step S215). Specifically, when the received power is equal to or higher than the minimum reception sensitivity and the throughput degradation amount is equal to or less than a threshold value, the change of the protocol specified time is permitted.

In the wireless base station 201, when the change of the protocol specified time is permitted, the protocol specified time changing unit 251 performs the change (step S216). Then, the protocol prescribed time change notification signal creating unit 252 creates a protocol prescribed time change notification signal for notifying the change.
Further, the duration calculation method changing unit 261 changes the duration calculation method (step S217). Then, the duration calculation method change notification signal creation unit 262 creates a duration calculation method change notification signal for notifying the change. Subsequently, the communication unit 211 transmits the protocol specified time change notification signal and the duration calculation method change notification signal to the wireless terminal station 202 (step S218).

  In the wireless terminal station 202, the communication unit 271 receives the protocol specified time change notification signal and the duration calculation method change notification signal, and changes the protocol specified time and duration calculation method (steps S219 and S220). And the communication part 271 transmits an authentication signal to the wireless base station 201 again (step S221).

  In the radio base station 201, the communication unit 211 receives the authentication signal. Since the protocol specified time is relaxed this time, the communication unit 211 can transmit an ACK signal corresponding to the authentication signal to the wireless terminal station 202 within the protocol specified time (step S222).

In the wireless terminal station 202, the communication unit 271 receives the ACK signal and transmits an association signal to the wireless base station 201 (step S223).
In the wireless base station 201, the communication unit 211 receives an association signal. And the communication part 211 will transmit the ACK signal corresponding to the said association signal to the radio | wireless terminal station 202, if an association signal is received (step S224).
In the wireless terminal station 202, the communication unit 271 receives the ACK signal and establishes a connection with the wireless base station 201, so that a data signal can be transmitted to the wireless base station 201 (step S225). .
In the wireless base station 201, when the communication unit 211 receives the data signal, the communication unit 211 transmits an ACK signal corresponding to the data signal to the wireless terminal station 202 (step S226).

As described above, in the second embodiment of the present invention, the radio base station 201 has the location information acquisition unit 210, and the radio terminal station 202 has the location information acquisition unit 270. Since the wireless base station 201 and the wireless terminal station 202 are located at a long distance, if the propagation delay time cannot satisfy the reference protocol specified time, the wireless base station 201 and the wireless terminal station 202 acquired by the wireless base station 201 A throughput degradation amount is calculated based on the position information. Then, when the received power is equal to or higher than the minimum reception sensitivity and the throughput deterioration amount is equal to or less than the threshold value, the change of the protocol specified time can be permitted. As a result, communication between the radio base station 201 and the radio terminal station 202 can be established while the throughput degradation amount is kept below a certain value.
In addition, since the above series of processing is individually performed for each wireless terminal station 202, the protocol specified time of the wireless terminal station 202 that can satisfy the reference protocol specified time is not changed. Accordingly, it is possible to prevent the deterioration of the throughput in the wireless terminal station other than the wireless terminal station 202 that relaxes the protocol specification time.

[Third Embodiment]
FIG. 7 is a block diagram of a radio access system according to the third embodiment of the present invention. As shown in FIG. 7, the system according to the third embodiment of the present invention includes a radio base station 301 and a radio terminal station 302.

  The radio base station 301 includes a communication unit 311, a transmission / reception start time acquisition unit 320, a transmission delay time calculation unit 321, a throughput calculation unit 322, a received power measurement unit 331, a transmission rate determination unit 332, a reference A throughput calculation unit 333, a throughput deterioration amount calculation unit 341, a protocol specification time change determination unit 342, a protocol specification time change unit 351, a protocol specification time change notification signal creation unit 352, a duration calculation method change unit 361, And a duration calculation method change notification signal creation unit 362.

  The wireless terminal station 302 includes a communication unit 371, a transmission start time notification signal creation unit 372, and a synchronization establishment unit 373.

  In the third embodiment, the transmission delay time is calculated based on the time required for communication between the radio base station 301 and the radio terminal station 302, and the throughput degradation amount is calculated. The basic configuration of the third embodiment is the same as that of the first embodiment.

In the radio access system according to the third embodiment, the radio base station 301 is further provided with a transmission / reception start time acquisition unit 320 and a transmission delay time calculation unit 321 as compared with the first embodiment. .
When the transmission / reception start time acquisition unit 320 receives a signal for notifying the transmission start time from the wireless terminal station 302 (hereinafter referred to as a transmission start time notification signal), the transmission start time and the reception start time of the transmission start time notification signal. To get. The transmission delay time calculation unit 321 calculates the transmission delay time from the transmission start time and the reception start time acquired by the transmission / reception start time acquisition unit 320. The throughput calculator 322 calculates the throughput from the transmission delay time calculated by the transmission delay time calculator 321. About another structure, it is the same as that of the above-mentioned 1st Embodiment.

Further, in the wireless access system according to the third embodiment, the wireless terminal station 302 is further provided with a transmission start time notification signal creation unit 372 as compared to the first embodiment described above.
The transmission start time notification signal creation unit 372 creates a transmission start time notification signal. About another structure, it is the same as that of the above-mentioned 1st Embodiment.

FIG. 8 is a sequence diagram according to the third embodiment of the present invention. Processing in the wireless access system according to the third embodiment of the present invention will be described with reference to the sequence diagram of FIG.
In FIG. 8, in the wireless base station 301, the communication unit 311 transmits a beacon signal to the wireless terminal station 302 (step S301).
In the wireless terminal station 302, the communication unit 371 receives the beacon signal, and the synchronization establishment unit 373 determines the wireless base station 301 to be connected based on the beacon signal (step S302), and performs time synchronization. Establish (step S303).

In the wireless terminal station 302, the communication unit 371 transmits an authentication signal to the wireless base station 301 in order to establish a connection with the wireless base station 301 (step S304).
In the radio base station 301, the communication unit 311 receives the authentication signal, and when it is in time within the reference protocol prescribed time, transmits an ACK signal corresponding to the authentication signal to the radio terminal station 302 (step S305). ).
In the wireless terminal station 302, when the ACK signal cannot be received within the reference protocol specified time, the communication unit 371 retransmits the authentication signal to the wireless base station 301 (step S306). When the number of retransmissions of the authentication signal exceeds the maximum number of retransmissions (step S307), the communication unit 371 transmits the transmission start time notification signal generated by the transmission start time notification signal generation unit 372 to the radio base station 301. (Step S308).

  In the wireless base station 301, the communication unit 311 receives a transmission start time notification signal from the wireless terminal station 302. Then, the transmission / reception start time acquisition unit 320 acquires the transmission start time and the reception start time of the transmission start time notification signal from the transmission start time notification signal (step S309). Also, the received power measuring unit 331 measures the received power of the transmission start time notification signal (step S310). Then, the transmission rate determining unit 332 determines a transmission rate from the received power (step S311). Subsequently, the reference throughput calculation unit 333 calculates the reference throughput from the transmission rate and the reference protocol specified time (step S312).

  In the radio base station 301, the transmission delay time calculation unit 321 calculates the transmission delay time from the transmission start time and the reception start time (step S313a). Then, the throughput calculation unit 322 calculates the throughput from the transmission delay time (step S313b).

  In the radio base station 301, the throughput deterioration amount calculation unit 341 calculates a throughput deterioration amount from the throughput and the reference throughput (step S314). Then, the protocol specified time change determination unit 342 determines whether or not the protocol specified time can be changed from the received power and the throughput degradation amount (step S315). Specifically, when the received power is equal to or higher than the minimum reception sensitivity and the throughput degradation amount is equal to or less than a threshold value, the change of the protocol specified time is permitted.

In the wireless base station 301, when the change of the protocol specified time is permitted, the protocol specified time changing unit 351 performs the change (step S316). Then, the protocol specified time change notification signal creation unit 352 creates a protocol specified time change notification signal for notifying the change.
Further, the duration calculation method changing unit 361 changes the duration calculation method (step S317). Then, duration calculation method change notification signal creation section 362 creates a duration calculation method change notification signal for notifying the change. Subsequently, the communication unit 311 transmits the protocol specified time change notification signal and the duration calculation method change notification signal to the wireless terminal station 302 (step S318).

  In the wireless terminal station 302, the communication unit 371 receives the protocol specified time change notification signal and the duration calculation method change notification signal, and changes the protocol specified time and the duration calculation method (steps S319 and S320). And the communication part 371 transmits an authentication signal to the wireless base station 301 again (step S321).

  In the radio base station 301, the communication unit 311 receives the authentication signal. Since the protocol specified time is relaxed this time, the communication unit 311 can transmit an ACK signal corresponding to the authentication signal to the wireless terminal station 302 within the protocol specified time (step S322).

In the wireless terminal station 302, the communication unit 371 receives the ACK signal and transmits an association signal to the wireless base station 301 (step S323).
In the radio base station 301, the communication unit 311 receives an association signal. When receiving the association signal, the communication unit 311 transmits an ACK signal corresponding to the association signal to the wireless terminal station 302 (step S324).
In the wireless terminal station 302, the communication unit 371 receives the ACK signal and establishes a connection with the wireless base station 301, so that a data signal can be transmitted to the wireless base station 301 (step S325). .
In the wireless base station 301, when the communication unit 311 receives the data signal, the wireless base station 302 transmits an ACK signal corresponding to the data signal to the wireless terminal station 302 (step S326).

As described above, in the third embodiment of the present invention, the radio base station 301 has the transmission / reception start time acquisition unit 320, and the radio terminal station 302 has the transmission start time notification signal creation unit 372. When the propagation delay time cannot satisfy the reference protocol specified time because the radio base station 301 and the radio terminal station 302 are located at a long distance, the transmission start time and the reception start time acquired by the radio base station 301 are used. The throughput degradation amount is calculated. Then, when the received power is equal to or higher than the minimum reception sensitivity and the throughput deterioration amount is equal to or less than the threshold value, the change of the protocol specified time can be permitted. As a result, communication between the radio base station 301 and the radio terminal station 302 can be established while the throughput degradation amount is kept below a certain value.
Further, since the above-described series of processing is individually performed for each wireless terminal station 302, the protocol specified time of the wireless terminal station 302 that can satisfy the reference protocol specified time without changing the propagation delay time is not changed. Therefore, it is possible to prevent the deterioration of the throughput in the wireless terminal station other than the wireless terminal station 302 that relaxes the protocol specification time.

[Fourth Embodiment]
FIG. 9 is a block diagram of a radio access system according to the fourth embodiment of the present invention. As shown in FIG. 9, the radio access system according to the fourth embodiment of the present invention includes a flexible radio base station 401, a radio terminal station 402, and a signal processing device 403.
Here, the flexible wireless base station 401, the wireless terminal station 402, and the signal processing device 403 use a personal computer as a signal processing server or a device such as a home gateway or a service gateway in a LAN environment. A flexible network. The flexible radio base station 401 is a radio base station in such a flexible network.

  The flexible wireless base station 401 includes a communication unit 411, a response signal transmission availability determination unit 420, a request protocol specified time calculation unit 421, a throughput calculation unit 422, a received power measurement unit 431, a transmission rate determination unit 432, Reference throughput calculation unit 433, throughput degradation amount calculation unit 441, protocol specified time change determination unit 442, protocol specified time change unit 451, protocol specified time change notification signal creation unit 452, and duration calculation method change unit 461 And a duration calculation method change notification signal creation unit 462.

The wireless terminal station 402 includes a communication unit 471 and a synchronization establishment unit 473.
The signal processing device 403 includes a communication unit 481.

  In the first embodiment described above, the radio base station 101 calculates the throughput degradation amount based on the throughput calculation information notification signal received from the radio terminal station 102. Further, in the second embodiment, the radio base station 201 calculates a transmission delay time based on the acquired location information of the radio terminal station 202 and the location information of the radio terminal station 202 acquired from the radio terminal station 202, and throughput degradation occurs. The amount is calculated. In the third embodiment, the radio base station 301 calculates the transmission delay time based on the transmission start time and the reception start time acquired from the radio terminal station 302, and calculates the throughput deterioration amount.

  On the other hand, in the fourth embodiment, when the flexible wireless base station 401 determines that the transmission of the ACK signal is not in time within the reference protocol specified time, the protocol specification required to keep the transmission of the ACK signal in time. A time (hereinafter referred to as a request protocol specified time) is calculated, and a throughput deterioration amount is calculated based on the calculated request protocol specified time.

That is, in the radio access system according to the fourth embodiment, the flexible radio base station 401 further includes a response signal transmission availability determination unit 420, a request protocol prescribed time calculation unit 421, and the first embodiment. Is provided.
When the response signal transmission availability determination unit 420 receives a signal (for example, a data signal or an authentication signal) that needs to be transmitted from the wireless terminal station 402, the response signal is transmitted within the reference protocol specified time. Judge whether it is in time. When the response signal transmission availability determination unit 420 determines that the response signal transmission is not in time for the reference protocol specified time, the request protocol specified time calculation unit 421 calculates a request protocol specified time for delaying the response signal transmission. . The throughput calculation unit 422 calculates the throughput from the request protocol specified time calculated by the request protocol specified time calculation unit 421 and the transmission rate determined by the transmission rate determination unit 432. About another structure, it is the same as that of the above-mentioned 1st Embodiment.

  In the fourth embodiment, since the processing capability of the flexible wireless base station 401 is low, the processing time (in the IEEE 802.11 standard, SIFS is specified as 16 μs in the shortest case) cannot satisfy the standard protocol specification time. The NAV period is set to a period obtained by adding the processing time of the flexible radio base station 401 to the sum of the frame lengths of the SIFS and ACK signals, and this process is performed for each radio terminal station 402 by the protocol specified time. This is implemented as a process to alleviate this.

FIG. 10 is a sequence diagram according to the fourth embodiment of the present invention. Processing in the wireless access system according to the fourth embodiment of the present invention will be described with reference to the sequence diagram of FIG.
In FIG. 10, in the flexible radio base station 401, the communication unit 411 transmits a beacon signal to the radio terminal station 402 (step S401).
In the wireless terminal station 402, the communication unit 471 receives the beacon signal, and the synchronization establishment unit 473 determines the flexible wireless base station 401 to be connected based on the beacon signal (step S402), and time synchronization. Is established (step S403).

In the wireless terminal station 402, the communication unit 471 transmits an authentication signal to the flexible wireless base station 401 in order to establish a connection with the flexible wireless base station 401 (step S404).
In the flexible wireless base station 401, the communication unit 411 receives the authentication signal. Then, the response signal transmission availability determination unit 420 determines whether or not the transmission of the ACK signal corresponding to the authentication signal is in time within the reference protocol specified time (step S405). Subsequently, when it is determined that the transmission of the ACK signal is in time within the reference protocol specified time, the communication unit 411 transmits the ACK signal to the wireless terminal station 402 (step S406).

In the fourth embodiment, since the flexible radio base station 401 determines whether or not the transmission of the ACK signal is in time within the standard protocol stipulated time, the number of retransmissions of the authentication signal has exceeded the maximum number of retransmissions. In such a case, the wireless terminal station 402 does not perform an operation of transmitting a throughput calculation information notification signal to the flexible wireless base station 401 (see step S106 to step S108 in FIG. 2).
When the flexible radio base station 401 determines that the transmission of the ACK signal is not in time within the reference protocol specified time, the request protocol specified time calculation unit 421 sets the request protocol specified time for the transmission of the ACK signal in time. Calculate (step S409). The request protocol specified time is calculated by measuring the time required to start transmission of the ACK signal after receiving a signal (here, the authentication signal) that needs to transmit the ACK signal. Done.

  In flexible radio base station 401, received power measuring section 431 measures the received power of the authentication signal (step S410). Then, the transmission rate determining unit 432 determines a transmission rate from the received power (step S411). Subsequently, the reference throughput calculation unit 433 calculates the reference throughput from the transmission rate and the reference protocol specified time (step S412).

  In the flexible wireless base station 401, the throughput calculation unit 422 calculates the throughput from the request protocol specified time and the determined transmission rate (step S413).

  In the flexible wireless base station 401, the throughput deterioration amount calculation unit 441 calculates a throughput deterioration amount from the throughput and the reference throughput (step S414). Then, the protocol specified time change determination unit 442 determines whether or not the protocol specified time can be changed from the received power and the throughput degradation amount (step S415). Specifically, when the received power is equal to or higher than the minimum reception sensitivity and the throughput degradation amount is equal to or less than a threshold value, the change of the protocol specified time is permitted.

In the flexible wireless base station 401, when the change of the protocol specified time is permitted, the protocol specified time changing unit 451 executes the change (step S416). Then, the protocol specified time change notification signal creating unit 452 creates a protocol specified time change notification signal for notifying the change.
Further, the duration calculation method changing unit 461 changes the duration calculation method (step S417). Then, the duration calculation method change notification signal creation unit 462 creates a duration calculation method change notification signal for notifying the change. Subsequently, the communication unit 411 transmits the protocol specified time change notification signal and the duration calculation method change notification signal to the wireless terminal station 402 (step S418).

  In the wireless terminal station 402, the communication unit 471 receives the protocol specified time change notification signal and the duration calculation method change notification signal, and changes the protocol specified time and duration calculation method (steps S419 and S420). Then, the communication unit 471 transmits the authentication signal to the flexible radio base station 401 again (step S421).

  In the flexible wireless base station 401, the communication unit 411 receives the authentication signal. Since the protocol specified time is relaxed this time, the communication unit 411 can transmit the ACK signal corresponding to the authentication signal to the wireless terminal station 402 within the protocol specified time (step S422).

In the wireless terminal station 402, the communication unit 471 receives the ACK signal and transmits an association signal to the flexible wireless base station 401 (step S423).
In the flexible radio base station 401, the communication unit 411 receives an association signal. And the communication part 411 will transmit the ACK signal corresponding to the said association signal to the radio | wireless terminal station 402, if an association signal is received (step S424).
In the wireless terminal station 402, the communication unit 471 receives the ACK signal and establishes a connection with the flexible wireless base station 401, so that a data signal can be transmitted to the flexible wireless base station 401 (step). S425).
In the flexible wireless base station 401, when the communication unit 411 receives the data signal, the communication unit 411 transmits an ACK signal corresponding to the data signal to the wireless terminal station 402 (step S426).

FIG. 11 is a conceptual diagram relating to a change in the duration calculation method in the fourth embodiment of the present invention. FIG. 11A shows a normal response sequence that can satisfy the standard protocol prescribed time. FIG. 11B shows a response sequence in the case where the standard protocol prescribed time cannot be satisfied and the duration calculation method is changed.
As shown in FIG. 11, when a data (Data) signal is transmitted from the wireless terminal station 402 to the flexible wireless base station 401, the flexible wireless base station 401 performs reception processing of the data signal, and the signal processing device 403 Send a data signal. In the normal response sequence, the flexible radio base station 401 transmits an ACK signal to the radio terminal station 402 after the SIFS time has elapsed since the data signal was received. Here, the SIFS time is 16 μs. As shown in FIG. 11A, in the normal response sequence, the total frame length of the SIFS and ACK signals is set in a NAV (Network Allocation Vector) period. Other wireless terminal stations in the vicinity that are not involved in transmission and reception prohibit transmission during this NAV period.
When the signal processing time of the flexible wireless base station 401 is short, as shown in FIG. 11A, the wireless terminal station 402 can receive the ACK signal from the flexible wireless base station 401 within the NAV period T11, Satisfy the standard protocol specified time.

  On the other hand, as shown in FIG. 11B, if the signal processing time of the flexible wireless base station 401 is long, the reference protocol specified time cannot be satisfied. In this example, the flexible wireless base station 401 transmits an ACK signal to the wireless terminal station 402 after [16 μs + β] has elapsed since the data signal was received. In this case, the wireless terminal station 402 cannot receive the ACK signal from the flexible wireless base station 401 within the NAV period T11. Therefore, as shown in FIG. 11B, the NAV period is set to be extended to a period T12 obtained by adding the processing time β to the total frame length of the SIFS and ACK signals. Thus, by extending the NAV period to T12, the wireless terminal station 402 can receive the ACK signal from the flexible wireless base station 401 within the NAV period T12.

As described above, in the fourth embodiment of the present invention, the flexible radio base station 401 includes the response signal transmission availability determination unit 420 and the request protocol specified time calculation 421. If the processing time cannot satisfy the reference protocol specified time because the processing capacity of the flexible wireless base station 401 is low, the throughput degradation amount is calculated based on the requested protocol specified time calculated by the flexible wireless base station 401. Then, when the received power is equal to or higher than the minimum reception sensitivity and the throughput deterioration amount is equal to or less than the threshold value, the change of the protocol specified time can be permitted. As a result, communication between the flexible radio base station 401 and the radio terminal station 402 can be established while the throughput degradation amount is kept below a certain value.
Further, since the above series of processing is individually performed for each wireless terminal station 402, the protocol specified time of the wireless terminal station 402 that can satisfy the reference protocol specified time is not changed. Therefore, it is possible to prevent the deterioration of the throughput in the wireless terminal station other than the wireless terminal station 402 that relaxes the protocol specification time.

DESCRIPTION OF SYMBOLS 101 ... Wireless base station, 102 ... Wireless terminal station, 111 ... Communication part, 121 ... Throughput calculation information acquisition and calculation part, 122 ... Throughput calculation part, 131 ... Received power measurement part, 132 ... Transmission rate determination part, 133 ... Reference throughput calculation unit, 141 ... Throughput degradation amount calculation unit, 142 ... Protocol specified time change determination unit, 151 ... Protocol specified time change unit, 152 ... Protocol specified time change notification signal creation unit, 161 ... Duration calculation method change unit, 162 ... Duration calculation method change notification signal creation unit, 171 ... Communication unit, 172 ... Information computation signal creation unit for throughput calculation, 173 ... Synchronization establishment unit, 201 ... Radio base station, 202 ... Radio terminal station, 210 ... Location information acquisition unit , 211 ... communication unit, 221 ... transmission delay time calculation unit, 222: Throughput calculation unit, 231 ... Received power measurement unit, 232 ... Transmission rate determination unit, 233 ... Reference throughput calculation unit, 241 ... Throughput deterioration amount calculation unit, 242 ... Protocol specification time change determination unit, 251 ... Protocol specification time change , 252 ... Protocol specified time change notification signal creation unit, 261 ... Duration calculation method change unit, 262 ... Duration calculation method change notification signal creation unit, 270 ... Location information acquisition unit, 271 ... Communication unit, 272 ... Location information notification signal Creation unit, 273 ... synchronization establishment unit, 301 ... radio base station, 302 ... radio terminal station, 311 ... communication unit, 320 ... transmission / reception start time acquisition unit, 321 ... transmission delay time calculation unit, 322 ... throughput calculation unit, 331: Received power measurement unit, 332 ... Transmission rate determination unit 333: Reference throughput calculation unit, 341: Throughput degradation amount calculation unit, 342 ... Protocol specified time change determination unit, 351 ... Protocol specified time change unit, 352 ... Protocol specified time change notification signal creation unit, 361 ... Duration calculation method change unit 362 ... Duration calculation method change notification signal creation unit, 371 ... Communication unit, 372 ... Transmission start time notification signal creation unit, 373 ... Synchronization establishment unit, 401 ... Flexible radio base station, 402 ... Radio terminal station, 403 ... Signal processing 411 ... communication unit 420 ... response signal transmission availability determination unit 421 ... request protocol specified time calculation unit 422 ... throughput calculation unit 431 ... reception power measurement unit 432 ... transmission rate determination unit 433 ... reference throughput calculation Part, 441 ... Throughput degradation Quantity calculation unit, 442 ... Protocol specified time change determination unit, 451 ... Protocol specified time change unit, 452 ... Protocol specified time change notification signal creation unit, 461 ... Duration calculation method change unit, 462 ... Duration calculation method change notification signal creation unit 471: Communication unit 473 ... Synchronization establishment unit 481 ... Communication unit

Claims (6)

A control method performed by a wireless system including a wireless terminal station and a wireless base station,
The wireless terminal station notifying the wireless base station of information necessary for calculating throughput;
The wireless base station calculating a throughput based on the information;
The wireless base station calculates a reference throughput based on a transmission rate and a reference protocol specified time;
The radio base station calculating a throughput degradation amount based on the throughput and the reference throughput;
The wireless base station determines whether or not the protocol specified time can be changed based on the received power and the deterioration amount; and
The wireless base station, when the received power is equal to or higher than a minimum reception sensitivity and the deterioration amount is equal to or lower than a threshold, changing a protocol specified time and a duration calculation method;
The wireless base station notifying the wireless terminal station of the changed protocol specified time and duration calculation method;
The wireless terminal station reflects the protocol specified time and the duration calculation method notified from the wireless base station on its own device,
A control method.   The control method according to claim 1, wherein the radio base station calculates the deterioration amount based on a distance between the radio base station and the radio terminal station.   The control method according to claim 1, wherein the radio base station calculates the deterioration amount based on a time required for communication between the radio base station and the radio terminal station.   The control method according to claim 1, wherein the radio base station calculates the deterioration amount based on a request protocol stipulated time calculated when a signal is received from the radio terminal station. A wireless system including a wireless terminal station and a wireless base station,
The wireless terminal station
A notification unit for notifying the wireless base station of information necessary for calculating throughput;
A change unit that reflects the protocol specified time and the duration calculation method notified from the radio base station on the own device,
The radio base station is
A throughput calculator that calculates the throughput based on the information;
A reference throughput calculation unit for calculating a reference throughput based on a transmission rate and a reference protocol specified time;
A throughput deterioration amount calculation unit for calculating a deterioration amount of the throughput based on the throughput and the reference throughput;
A protocol specification time change determination unit for determining whether or not the protocol specification time can be changed based on the received power and the deterioration amount;
When the received power is equal to or higher than the minimum reception sensitivity and the deterioration amount is equal to or less than a threshold, a changing unit that changes a protocol specified time and a duration calculation method;
A wireless system comprising: a notification unit that notifies the wireless terminal station of the changed protocol specified time and duration calculation method. A wireless base station that wirelessly communicates with a wireless terminal station,
A throughput calculation unit that is notified from the wireless terminal station and calculates a throughput based on information necessary for calculating the throughput;
A reference throughput calculation unit for calculating a reference throughput based on a transmission rate and a reference protocol specified time;
A throughput deterioration amount calculation unit for calculating a deterioration amount of the throughput based on the throughput and the reference throughput;
A protocol specification time change determination unit for determining whether or not the protocol specification time can be changed based on the received power and the deterioration amount;
When the received power is equal to or higher than the minimum reception sensitivity and the deterioration amount is equal to or less than a threshold, a changing unit that changes a protocol specified time and a duration calculation method;
A notification unit for notifying the wireless terminal station of the changed protocol specified time and duration calculation method;
A wireless base station comprising: