JP2007166373A - Wireless communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow transmitting stations and receiving stations to determine whether simultaneous transmission is possible, in the location topology of all wireless stations. <P>SOLUTION: In this wireless communication method, the interference power information and the received power information of a control signal from a communication partner are added to RTS105, 107/CTS106, 108 packet. A wireless station which has received the RTS/CTS packet calculates a required signal to interference signal power ratio based on the received power of the RTS/CTS packet to determine whether simultaneous transmission is possible or not. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication method capable of realizing high space utilization efficiency by simultaneously transmitting a plurality of links in a wireless communication system in which a plurality of links coexist.

  Conventionally, in a wireless communication system that performs packet wireless transmission such as a wireless LAN, an access control method based on carrier sense has been widely used. For example, Non-Patent Document 1 describes a CSMA / CA scheme that uses a data transmission request (RTS) and a reception ready (CTS) control packet in addition to carrier sense based on received signal strength. The RTS and CTS frames describe the scheduled period for using the radio line, and radio stations that have received RTS and CTS other than the communication partner prohibit transmission during this period, thereby preventing packet collisions. This is called virtual carrier sense. By using RTS / CTS, if the CTS transmitted by the receiving station can be received, the existence of the transmitting station can be known, so that the transmitting stations that cannot recognize each other's carriers transmit packets to the same receiving station. The hidden terminal problem causing packet collision can be solved. Thus, RTS / CTS is intended to avoid packet collision due to the hidden terminal problem. However, a radio station that has received RTS / CTS does not transmit even if the received power of RTS / CTS is such a weak received signal strength that does not affect the target communication, so-called exposed terminal problem occurs. As a result, the transmission capacity of the entire system is limited.

  Non-Patent Document 1 improves the transmission capacity of the entire system as a countermeasure against the above-mentioned problem, by not simultaneously stopping the transmission terminal that received the CTS, but performing simultaneous transmission if a specific condition is satisfied. Yes. FIG. 16 shows a conceptual diagram of Non-Patent Document 1. Assume that a101 is transmitting data to a102. a101 transmits an RTS to a102 before transmitting data, and a102 transmits a CTS to a101. Here, a102 adds the received power information of the RTS packet and the interference power information of a102 to the CTS packet. When a103 receives the CTS, the a103 refers to the CTS packet and further measures the received power information of the CTS packet. If a101 and a103 transmit with equal power, a103 estimates that if a103 transmits data, the interference power of a102 increases by the received power of the CTS packet. If a103 calculates the ratio (SINR) between the desired signal power of a102 when transmitted by itself and the signal power that causes interference (SINR), if it is determined that the transmission of a103 does not affect the reception of a102, then go to a104 RTS is transmitted.

  Similar to Non-Patent Document 1, Patent Document 1 is also intended to determine the simultaneous transmission based on SINR and increase the transmission capacity of the entire system. FIG. 17 shows a conceptual diagram of Patent Document 1. STA1 and STA2 obtain the ratio of the beacon received power from AP1 as the desired signal power and the beacon received power from AP2 as the interference signal power. Similarly, STA3 and STA4 obtain the ratio of the received power of the beacon from AP2 as the desired signal power and the received power of the beacon from AP1 as the interference signal power. Each AP acquires SINR information by a beacon acquired by the STA, and transmits a data signal at the same time if the transmission destination STA is capable of simultaneous reception.

For example, in FIG. 17, each AP determines that simultaneous transmission to STA1, STA3, and STA4 is possible, but simultaneous transmission to STA2 and STA3 is impossible.
Japanese Patent Laid-Open No. 2004-260637 Interference Aware (IA) MAC: an Enhancement to IEEE 802.11b DCF / IEEE VTC Fall 2003

  However, in Non-Patent Document 1, only the transmitting station that has received the CTS determines simultaneous transmission.

  For this reason, for example, in FIG. 16, when a102 is a transmitting station, a101 is a receiving station, and a103 receives an RTS, it is possible to determine simultaneous transmission, such as being unable to determine simultaneous transmission. There is a problem that the arrangement topology of the wireless stations is limited. Further, in Patent Document 1, although transmission determination of simultaneous transmission of an AP that is a transmission station is performed, there is a problem that a collision of ACK transmission of a STA that is a reception station is not considered. The present invention solves the above-described conventional problems, and enables a transmitting station and a receiving station to determine simultaneous transmission in a wireless communication system that performs autonomous distributed control in an arrangement topology of all wireless stations. .

  In order to solve the above-described conventional problem, the wireless communication method of the present invention is configured such that when a wireless station makes a transmission data call request, the wireless transmission station transmits the interference power information of the local station before transmitting the data. A step of transmitting the added control signal, and when the radio receiving station that is the destination of the control signal receives this signal, a control packet to which the received power of the control signal and the interference power information of the received radio station are added is transmitted. A wireless station other than the wireless receiving station that has received the control signal of the wireless transmitting station, when transmitting the signal, waits for transmission until the scheduled transmission time of the control signal of the wireless receiving station, and The wireless station which received the control signal performs the packet transmission determination based on the received packet of the control signal of the wireless receiver before transmitting the packet.

  According to the present invention, a signal from an interference source reaches, but it is possible for a transmission / reception station that can communicate without affecting the communication of the interference source and without being affected by the interference source to perform communication. The transmission capacity of the entire system can be improved. Further, since the transmitting station and the receiving station do not need to depend on the transmission timing of the terminal serving as an interference source, simultaneous transmission is possible even in a system configuration without a control station or a base station, such as an ad hoc configuration.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram of the present invention. Consider a case where a call request to the wireless station B is generated in the wireless station A. The wireless station A first transmits an RTS to the wireless station B (RTS (A)), and the wireless station B that has received the RTS (A) returns a CTS to the wireless station A (CTS (B)). The wireless station A that has received the CTS (B) transmits data to the wireless station B. Consider a case where the communication of the wireless station AB is an interference source when the wireless station C transmits data to the wireless station D. That is, a case is considered in which a call request is generated in the wireless station C at any time after the transmission of RTS (A).

  FIG. 2 shows a flowchart of packet transmission between the wireless station A and the wireless station B. First, the wireless station A transmits an RTS packet to the wireless station B. At this time, the RTS packet is transmitted with the interference power information at the wireless station A and the received power information of the signal from the past wireless station B added (flow 201). This is because information on the attenuation amount of the signal power between the radio stations AB is added to the RTS packet. The received wireless station B adds the interference power information in B and the received power information of the RTS packet transmitted by the wireless station A, and transmits the CTS packet to the wireless station A (flow 202). Although it is a method for measuring interference power information, as a preferable measurement method, there is a method in which the signal power in the communication channel is periodically measured and the power having the largest received power among the past predetermined number of times is used as the interference power. .

  The wireless station A that has received the CTS packet transmits a normal data signal to the wireless station B when there is reception power information of a signal from the wireless station B in the past when the RTS packet is transmitted. If there is no signal reception power information from B in the past, the CTS reception power information from B just received is added to the data packet for transmission. This is to make it possible to acquire the received power information at the wireless station A of the signal transmitted by the wireless station B to the wireless station that has received only RTS (A). Note that the radio station B does not necessarily need to transmit a data signal to the radio station B only when there is no signal reception power information from the past radio station B, and always adds CTS reception power information to the data signal. You may do it. When the mobility of the radio station is high, the difference between the past received power information and the actual received power becomes large. Therefore, by adding the received power information to the data signal, the reliability is improved by other radio stations. High reception power information can be notified.

  A general flowchart in which the transmitting station C and the transmitting station D determine simultaneous transmission when a call request to the transmitting station D is generated in the transmitting station C will be described with reference to FIGS. First, when a call request is generated in the wireless station C, the wireless station C determines whether or not the RTS (A) transmitted by the wireless station A has been received (flow 301). If RTS (A) has not been received, the wireless station C determines whether CTS (B) has been received (flow 303). If CTS (B) is not received, RTS is transmitted (flow 311). When CTS (B) is received, it is determined whether the transmission of C does not interfere with the reception of B along with the contents of the CTS (B) packet. If there is no interference, the RTS is transmitted to the radio station D (flow 311). Similarly to the RTS (A) packet transmitted by the wireless station A, the past signal reception power information of the wireless station D and interference power information of the wireless station C are added to this RTS. Note that the preferable past received power information is the received power information of the packet transmitted from the wireless station D to the wireless station C most recently, such as a data packet or an ACK packet transmitted from the wireless station D to the wireless station C in the past. Conceivable. In the flow 301, when the wireless station C receives RTS (A), the wireless station C may subsequently receive the CTS packet CTS (B) of the wireless station B, so the scheduled reception time of CTS (B) (Step 302).

  Here, when the past history information is not added to the RTS (A) packet received by the wireless station C, it is considered that the wireless station A adds the past received power information to the data signal and transmits it. C waits for transmission until the scheduled reception time of the data signal of the wireless station A (flow 305). If there is history information, it is immediately determined whether CTS (B) has been received (flow 306). When the CTS (B) is received in the flow 306, the wireless station C has received the RTS (A) and the CTS (B), and therefore the wireless station C transmits the data signal. There is a possibility that reception of data at the wireless station B and reception of ACK transmitted by the wireless station B at the wireless station A may be hindered. For this reason, in the flow 307, the wireless station C determines whether the transmission of the signal of the wireless station C does not interfere with the reception of the wireless station AB, and the contents of the received RTS (A) packet and CTS (B) packet, respectively. A determination is made based on the received power information of the packet, and if it is determined not to interfere, an RTS (C) packet is transmitted. On the other hand, as a result of the determination, if it is determined that the transmission of the signal of the wireless station C interferes with the reception of the wireless station AB, the wireless station C stops the transmission of the RTS (C) packet (flow 309). A specific determination method will be described later.

  In the flow 306, if the CTS (B) is not received, the wireless station C has received only the RTA (A), so it is determined whether or not the transmission of the wireless station C interferes with the ACK reception of the wireless station A. If it is determined not to interfere, an RTS (C) packet is transmitted. Here, when there is past received power information in the RTS (A) packet, the wireless station C determines simultaneous transmission based on the contents of the RTS (A) packet and the received power information of the RTS (A) packet. Do. On the other hand, when the past received power information does not exist, the wireless station C determines simultaneous transmission based on the information included in the data signal and the received power information. If the wireless station C determines that the transmission of the local station interferes with the reception of the wireless station AB, the wireless station C stops transmitting the RTS (flow 309).

  FIG. 4 shows a flowchart until the wireless station D that has received the RTS (C) packet determines whether or not to transmit the CTS (D) packet. The wireless station D that has received the RTS (C) transmits a CTS (D) packet if it does not receive the RTS (A), as in the case of FIG. At this time, interference power information at the radio station D and reception power information of RTS (C) are added to the CTS (D) packet. A series of operations from the flow 302 to the flow 306 is the same as the operation of the wireless station C shown in FIG.

  When the CTS (B) is received in the flow 306, the wireless station C first transmits the transmission of the wireless station D based on the information of the RTS (A) packet and the CTS (B) packet and the received power information of each packet. Determines whether to interfere with reception of the radio station AB. Further, the wireless station D determines whether or not the transmission of the wireless station AB interferes with the data reception of the wireless station D by using the contents of the RTS (C) packet and the received power information as a determination material. As a result of these determinations, if the transmission of the wireless station D does not interfere with the reception of the wireless station AB, and the transmission of the wireless station AB does not interfere with the reception of the wireless station D, the wireless station D transmits a CTS (D) packet. Is transmitted to the wireless station C (flow 407).

  In the flow 306, if the wireless station D does not receive CTS (B), the transmission of the wireless station D does not interfere with the reception of the wireless station A, and the transmission of the wireless station A interferes with the transmission of the wireless station D. If it is determined not to do so (flow 408), a CTS packet is transmitted (flow 403). When the wireless station D determines that the transmission of the wireless station D interferes with the reception of the wireless station A, or when it determines that the transmission of the wireless station A interferes with the reception of the wireless station D, the wireless station D stops transmitting the CTS packet (flow). 409). Regarding the determination method of the wireless station D, as in the case of the wireless station C, when the past received power information exists in the RTS (A) packet, the wireless station D determines the contents of the RTS (A) packet and the RTS (A ) Judge the simultaneous transmission based on the received power information of the packet. On the other hand, when there is no past received power information, the wireless station D determines simultaneous transmission based on the information included in the data signal and the received power information.

  FIG. 5 shows a series of flowcharts from when the wireless station C receives the CTS packet until it transmits data to the wireless station D.

  A series of operations from the flow 302 to the flow 306 is the same as the operation of the wireless station C shown in FIG.

  In flow 303, it is determined whether or not CTS (B) has been received. If not, data is transmitted (flow 511). If CTS (B) is not received, it is determined whether D's transmission does not interfere with B's reception and B's transmission does not interfere with D's reception (flow 510).

  If the wireless station C does not receive RTS (A), the wireless station C transmits data (flow 511).

  In step 306, if the wireless station C receives CTS (B), the wireless station C uses the information added to CTS (D) and the information received by RTS (A) and CTS (B) to wireless station AB. Whether or not the transmission of the wireless station C interferes with the reception of the wireless station C is determined. If it is determined that the transmission is not disturbed, the data is transmitted. If it is determined that the transmission is disturbed, the data transmission is stopped (flow 509).

  If the CTS (B) is not received in the flow 306, the wireless station C determines whether the transmission of the wireless station A interferes with the reception of the wireless station C based on the information received by the RTS (A). If it is determined that there is no interference, the data is transmitted. If the interference is interrupted, the data transmission is stopped. Here, when there is past received power information in the RTS (A) packet, the wireless station C determines simultaneous transmission based on the contents of the RTS (A) packet and the received power information of the RTS (A) packet. Do. On the other hand, when the past received power information does not exist, the wireless station C determines simultaneous transmission based on the information included in the data signal and the received power information.

  The above is a flowchart of the general operation of the radio transceiver station according to the present invention.

  Here, a detailed description of the operation including the method for determining simultaneous transmission will be given with the topology of the radio station in FIG. 10 as a representative.

  FIG. 6 shows a topology of terminal arrangement. Assume that the transmitting station 101 has not communicated with the receiving station 102 in the past.

  The transmitting station 101 transmits data to the receiving station 102. The transmitting station 101 transmits RTS (A) to the receiving station 102, and the receiving station 102 transmits CTS (B) to the transmitting station 101. The transmitting station 101 that has received the CTS from the receiving station 102 transmits data to the receiving station 102.

  The transmitting station 101 and the receiving station 102 can receive each other's RTS / CTS packets. Further, it is assumed that the transmission station (C) 103 can receive the RTS packet transmitted by the transmission station 101. The receiving station (D) 104 can receive 103 packets, but cannot receive control packets from the transmitting station 101 and the receiving station 102.

  FIG. 7 shows the frame format of the control packet and the data frame. Interference power information at the transmitting station 101 is added to the RTS (A) frame format 701 transmitted from the transmitting station 101 to the receiving station 102. The interference power information at the receiving station 102 and the received power information 701 are added to the CTS (B) frame format 702 transmitted from the receiving station 102 to the transmitting station 101. The RTS (C) frame format is obtained by adding the interference power information of the transmitting station 103 to the RTS frame. The CTS (D) frame format adds the interference information of the receiving station 104 and the received power information of 107 to the CTS frame.

  The frame format 705 of the data signal 110 transmitted by the transmitting station 101 is obtained by adding the reception power of the ACK signal 106 transmitted by the receiving station 102 and the interference power at the transmitting station 101 in addition to the normal data frame.

  FIG. 8 shows a flowchart when the past ACK received power information is not used. RTS (C) transmitted by the transmission station 101 is added with interference power information of the transmission station 101. The transmitting station 101 adds the CTS received power information P_A_CTS_B transmitted from the receiving station 102 to the data signal 110. The transmitting station 103 waits for transmission until the data transmission time (flow 801), and determines transmission of the RTS packet (flow 803).

  103 and the receiving station 102 transmit packets at the same time, the estimated received power SINR_A_ext at the transmitting station 101 is P_A_CTS_B as the received power of the transmitting station 101 of CTS (B), and further the data signal transmitted by the transmitting station 101 When the reception power at the transmission station 103 is P_C_DATA_A, it is expressed by (Equation 1).

  If the reception success threshold determined by the system is SINR_thr, it is determined whether SINR_A_ext is greater than SINR_thr (flow 802). If SINR_A_ext is larger than SINR_thr, the transmitting station 103 transmits an RTS packet to 104. The receiving station 104 that has received the RTS packet performs transmission determination of the CTS packet.

  The receiving station 104 that has received the CTS packet estimates the SINR of the transmitting station 103 according to the following (Equation 2), assuming that the reception power at the receiving station 104 of the RTS (C) transmitted by the transmitting station 103 is P_C_Data_A. Judgment is made.

  If the estimated reception SINR of the transmission station 103 is larger than SINR_thr, the reception station 104 transmits a CTS packet to the transmission station 103. The transmitting station 103 that has received the CTS packet transmits data to the receiving station 104.

  Here, I_C periodically measures the interference power, performs observation over a period from the reception of the RTS to the reception of the CTS, and it is desirable to set the maximum interference power among them. This makes it possible to estimate when the reception SINR of the transmission station 103 is most deteriorated during the RTS of the transmission station 101 or the CTS transmission of the reception station 102. As other methods, a method of measuring interference power in a specific period and setting the average value as interference power can be considered.

(Embodiment 2)
Another embodiment of the present invention will be described.

  This is an embodiment in the case where the transmitting station has communicated with the receiving station in the past, and the transmitting station holds the received power information from the past receiving station. It is assumed that the terminal arrangement is the same as in FIG.

  FIG. 9 shows the frame format of the control packet and the data frame.

  The RTS (A) frame format 901 transmitted from the transmitting station 101 to the receiving station 102 is added with the interference power information at the transmitting station 101 and the received power information of the ACK signal received from the past receiving station 102. The interference power information at the receiving station 102 and the received power information 701 are added to the CTS frame format 702 transmitted from the receiving station 102 to the transmitting station 101. Note that the information added to the frame format 701 does not necessarily need to be past ACK received power information, but may be received power information of a signal transmitted by the receiving station 102 in the past or CTS received power information.

  FIG. 10 shows a flowchart when there is past power information in the RTS packet of the transmitting station 101. Assume that a call request is generated in 103 after the transmitting station 101 transmits RTS. Since the transmission station 103 has received RTS (A), it waits for transmission until the scheduled reception time of CTS (B) (flow 1001). After waiting for transmission, since the transmission station 103 did not receive the CTS packet, the transmission station 103 determines whether or not transmission of the transmission station 103 interferes with reception of the transmission station 101 (flow 1002). The determination method will be described below.

  The transmitting station 103 estimates the past ACK received power added to the RTS packet of the transmitting station 101 as the received power of the transmitting station 101 when the receiving station 102 transmits a signal to the transmitting station 101. Thus, SINR_A_ext which is an estimated SINR of the transmission station 101 when the transmission station 103 transmits a signal is expressed by the following (Equation 3), assuming that the reception power at the transmission station 103 of the RTS transmitted by the transmission station 101 is P_C_RTS_A. expressed.

  If the reception success threshold of the radio station determined by the system is SINR_thr, the transmitting station 103 determines whether SINR_A_ext is greater than SINR_thr (flow 1002). If SINR_A_ext is larger than SINR_thr, it is presumed that even if the transmitting station 103 transmits, the transmitting station 101 can secure a sufficient SINR to receive the signal transmitted by the receiving station 102, so that 103 transmits an RTS packet to 104. To do. The receiving station 104 that has received the RTS packet from 103 uses the received power PS_RTS_R of the RTS packet, the interference power information I_C added to the RTS packet, and the received power at the transmitting station 103 of the RTS transmitted by the transmitting station 101 as P_C_RTS_A. Based on (Equation 4), the SINR of the transmitting station 103 when 104 transmits a signal is estimated.

  104 transmits a CTS packet if the estimated SINR_C_ext is greater than SINR_thr. 103 which received the CTS packet transmits a data packet to 104.

  Next, description will be made using another topology diagram.

  FIG. 11 shows a terminal arrangement diagram of the radio station. The transmitting station 1101 transmits data to the receiving station 1102. The transmitting station 1101 transmits RTS (A) to the receiving station 1102, and the receiving station 1102 transmits CTS (B) to the transmitting station 1101. The transmitting station 1101 that has received the CTS from the receiving station 1102 transmits data to the receiving station 1102. The transmitting station 1101 and the receiving station 1102 can receive each other's RTS / CTS packets. Further, it is assumed that the transmitting station 1103 can also receive the RTS packet transmitted from the transmitting station 1101 and the CTS packet transmitted from the receiving station 1102. The receiving station 1104 can receive the packet of the transmitting station 1103, but cannot receive the control packets of the transmitting station 1101 and the receiving station 1102.

  The frame format is shown in FIG. However, I_C of 1203 in FIG. 12 is the sum of the transmission signal of the transmission station 1101, the higher reception power of the reception signal of the reception station 1102 at the transmission station 1103, and the interference power at the transmission station 1103.

  FIG. 13 shows a flowchart. Assume that the transmitting station 1101 transmits an RTS, and immediately after that, a call request is generated in 1103. When 1103 receives RTS (A) of another station, 1103 waits for transmission until the scheduled reception time of CTS (B) (flow 1301). In the wireless station topology of FIG. 6, since 1103 receives the CTS (B) packet, after waiting for transmission, 1103 includes information on the frame format 701 of 1105 and the frame format 702 of 1106, and the information of each packet in 1103. RTS transmission determination is performed based on the received power information. The determination method will be described below.

  Consider a case where the signal 1103 and the receiving station 1102 transmit signals simultaneously. When receiving station 1102 transmits a signal with the same transmission power as RTS (A), the received power of the signal at transmitting station 1101 is estimated to be P_B_RTS_A. Similarly, the received power P_C_RTS_A at 1103 of RTS (A) transmitted by the transmitting station 1101 is estimated to be the received power at the transmitting station 1101 when 1103 transmits a signal with the same transmission power. Since the interference power at the transmission station 1101 is I_A from 901, the estimated reception power SINR_IS_ext at the transmission station 101 is expressed by (Equation 5).

  Next, consider a case where 1103 and transmitting station 1101 transmit packets simultaneously. If 1103 transmits with the same power as the receiving station 1102, the received power at the receiving station 1102 of the signal transmitted by 1103 is estimated as P_C_CTS_B. The reception power at the reception station 1102 of the signal transmitted from the transmission station 1101 is P_B_RTS_A because it is the reception power of RTS (A). The interference power at the receiving station 1102 is I_B from CTS (B). Therefore, assuming that the reception power at the transmission station 1103 of the CTS packet transmitted by the reception station 1102 is P_C_CTS_B, the estimated reception power SINR_B_ext at the reception station 1102 is expressed by (Equation 6).

  If the reception success threshold of the radio station determined by the system is SINR_thr, 1103 determines whether SINR_A_ext and SINR_B_ext are larger than SINR_thr (flow 1302). If SINR_A_ext and SINR_B_ext are larger than SINR_thr, even if 1103 transmits, it is estimated that transmission station 1101 and transmission station 1102 can secure a sufficient SINR for signal reception, and 1103 transmits an RTS packet to 1104.

  When the transmission of the local station and the transmission of the transmission station 1101 or the reception station 1102 overlap, the 1104 that has received the RTS packet similarly determines whether or not the 1103 can be received by estimating the SINR (flow 1303). The determination method will be described below. The signal reception power received by 1103 when 1104 transmits a signal is estimated to be P_B_RTS_A if 1104 transmits with the same power as the RTS packet of 1103. Since the interference power at 1103 is estimated as I_A from the information added to RTS (S), the estimated SINR of 1103 due to the transmission of 1104 is expressed by the equation (Equation 7).

  In the case of FIG. 11, it can be considered that the larger reception power of the transmission signal of the transmission station 1101 and the reception signal of the reception station 1102 is the dominant value of I_C.

  If SINR_C_ext is greater than SINR_thr, 1104 transmits a CTS. 1103 which received CTS starts data transmission, and 1104 which received data returns ACK.

  In all the embodiments described above, a system that transmits / receives an RTS / CTS packet is assumed. However, the present invention is not necessarily limited to a system that transmits / receives an RTS / CTS. The present invention is generally applicable to a wireless communication method for exchanging control signals with a new terminal. Furthermore, the present invention can be applied to a communication system that does not use a control signal by adding signal reception power information and interference signal power information to a data signal and an ACK packet.

  FIG. 14 shows a configuration diagram of the radio stations A and B in the present invention. The received power measuring unit 1402 is a part that measures the received power of the signal received by the wireless receiver 1407. The reception power of the RTS / CTS packet and the interference power are measured using the apparatus 1402. The past received power storage unit is a device that stores the content measured by the received power measurement unit, and can add information stored in 1401 to the control packet. Information measured by the received power measuring unit 1402 can be added to the data packet by the data packet generating unit 1404. When waiting for transmission until the scheduled reception time of the CTS packet or when waiting for transmission until the scheduled reception time of the data packet, the transmission standby unit 1405 temporarily waits for transmission of the data packet or control packet, and When it is time to perform, a signal is transmitted to the wireless transmitter 1406.

  FIG. 15 shows a configuration diagram of the radio stations C and D in the present invention.

  Based on the information measured by the received power measurement unit, the interference determination unit 1509 determines whether or not control packet transmission is possible based on the influence of transmission of the local station on other stations. Based on the information measured by the received power measurement unit, the interfered determination unit 1508 determines whether or not control packet transmission is possible from the influence of communication of other stations on the communication partner of the own station.

  A communication start availability determination unit 1510 performs transmission determination based on information measured by the received power measurement unit.

  The configurations of all the embodiments described above may be realized as an LSI that is typically an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include all or a part of the configuration of the above-described embodiment. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology can be applied.

  The wireless communication method according to the present invention is effective in a wireless system in which a large number of wireless stations are arranged in a certain space, such as a wireless LAN, because a high system transmission capacity can be obtained by simultaneously transmitting a plurality of links. . Further, it is particularly effective when high-speed and large-capacity data such as video information is continuously transmitted, which tends to cause a capacity shortage when a plurality of links are transmitted in a time division manner.

Schematic diagram in Embodiment 1 of the present invention Flowchart of packet transmission between radio stations in Embodiment 1 of the present invention Flowchart in Embodiment 1 of the present invention Flowchart in Embodiment 1 of the present invention Flowchart in Embodiment 1 of the present invention Terminal arrangement in Embodiment 1 of the present invention Frame diagram according to Embodiment 1 of the present invention Flowchart in Embodiment 1 of the present invention Frame diagram in Embodiment 2 of the present invention Flowchart in Embodiment 2 of the present invention Terminal arrangement diagram in Embodiment 2 of the present invention Frame diagram in Embodiment 2 of the present invention Flowchart in Embodiment 2 of the present invention Configuration diagram of radio stations A and B in the present invention Configuration diagram of radio stations C and D in the present invention Conceptual diagram of the first example of the present invention Conceptual diagram of Prior Example 2 of the present invention

Explanation of symbols

A to D radio stations 101 to 104 radio stations 105 and 107 RTS
106,108 CTS
109,110 Data 1101-1104 Radio stations 1105, 1107 RTS
1106, 1108 CTS
1109,1110 data

Claims (10)

A first wireless station transmitting a first control signal to which interference power information in the local station is added before transmission of the transmission data when a transmission data call request occurs;
A second wireless station that is a destination of the first control signal transmits a second control signal to which the received power information of the first control signal and interference power information in the own station are added;
The third wireless station receiving the first control signal waits for transmission until the scheduled transmission time of the second control signal;
A third wireless station that has received the second control signal determines whether simultaneous packet transmission is possible based on information of the second control signal before transmitting the packet. Wireless communication method. The first radio station further adds reception power information of a transmission signal from the second radio station received before transmitting the first control signal to the first control signal. The wireless communication method according to claim 1. The third wireless station that has received the first control signal further includes a step of determining whether or not simultaneous transmission of the packet is possible based on the information of the first control signal before transmitting the packet. The wireless communication method according to claim 2. The radio communication method according to claim 1, further comprising a step of transmitting a data packet in which the first radio station adds reception power information of the second control signal and interference power information in the own station. The third wireless station that has received the data packet to which the received power information of the second control signal and the interference power information in its own station have added information added to the data packet before transmitting the packet. 5. The wireless communication method according to claim 4, further comprising a step of determining whether or not simultaneous transmission of packets is possible. The wireless communication method according to claim 1, wherein the first control signal is an RTS packet. The wireless communication method according to claim 1, wherein the second control signal is a CTS packet. When the first radio station has not received a transmission signal from the second radio station before transmitting the first control signal, the received power information of the second control signal; The wireless communication method according to claim 2, further comprising a step of transmitting a data packet to which interference power information at the local station is added. When the third radio station that has received the first control signal does not have the received power information of the transmission signal from the second radio station in the first control signal, the scheduled transmission time of the data packet The wireless communication method according to claim 8, further comprising the step of waiting for transmission. The radio communication method according to claim 1, wherein the third radio station determines whether simultaneous transmission is possible based on a ratio of signal reception power and interference power calculated from information described in a control packet.

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