JP2005277753A - Wireless communication system, base station, and communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the impartiality of utilization of communication resources in a wireless communication system. <P>SOLUTION: In the wireless communication system wherein one or more communication terminals access a transmission medium to execute wireless communication as a result of executing access control among a plurality of communication terminals according to a prescribed transmission medium access control system, a base station is provided with a relay control section that revises contents of relay operations of a terminal transmission signal wirelessly transmitted from each communication terminal directly by itself or indirectly by way of operations of the communication terminals on the basis of relay control information obtained from any communication terminal and / or an actually measured value acquired by itself. Further, the relay control section is preferably provided with a function that controls the amount of relay processing resources reserved inside of itself for relaying the other terminal transmission signals in response to the relay control information in the case of receiving the relay control information addressed to itself. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless communication system, and is suitably applied to, for example, a case where a competitive medium access control system similar to a mobile phone network or CSMA / CA is used.

  The present invention also relates to a base station as a component of such a wireless communication system.

  Furthermore, the present invention relates to a communication terminal as a component of such a wireless communication system.

  In the technique disclosed in Patent Document 1 below, unfairness is associated with radio communication between a base station and each mobile station in a CDMA (Code Division Multiple Access) system by changing communication charges according to the degree of influence of mutual interference. Is to eliminate.

  When transmitting wirelessly to a mobile station that is located far from the base station and has a long communication distance with the base station, the base station increases the transmission power. Occur. Due to this interference, the transmission signal of the base station to mobile stations in the vicinity of the base station is greatly affected.

  In this case, the technique of Patent Document 1 eliminates unfairness by increasing charging for mobile stations located far from the base station and decreasing charging for mobile stations located near the base station. become.

On the other hand, there is a technology that realizes fair use by reducing the amount of interference caused by competition in the use of communication resources. In this technology, charging is performed based on the degree of channel congestion and the maximum transmission rate.
Japanese Patent Laid-Open No. 2003-189012 JP-A-7-283888

  By the way, the above-described techniques such as Patent Documents 1 and 2 are all applied when a third party operates a repeater having only an amplification function to assist communication between a relay station serving as a base station and a terminal station. It is not possible.

  This is because the techniques disclosed in Patent Documents 1 and 2 associate the transmission power set in the relay station and the terminal station with the communication resource that is actually consumed, but the third party is simply composed of the amplification function. If a small repeater is activated, even if a small transmission power is set for both the relay station and the terminal station, the repeater will amplify in the middle, and the communication resources that are actually consumed will increase. is there.

  For example, the repeater amplifies a signal received from a communication terminal (corresponding to the terminal station) A to a predetermined signal strength (for example, a fixed value) and transmits the amplified signal to the communication terminal (corresponding to the relay station). ) When B receives a signal and communication between the communication terminals A and B via the relay is established, the communication terminals A and B can reduce (or eliminate) the influence of interference from themselves. Even if the signal strength at the time of transmission is controlled, it is not possible to control the signal strength at the time when the repeater transmits for relaying. There is also a high possibility that the allocation of communication resources will be far from optimal as a whole.

  The fact that the fairness of the use of communication resources is impaired means that, when viewed from individual communication terminals, only a very small amount of communication resources can be obtained compared to the total amount of communication resources, resulting in a decrease in throughput and the packet to be transmitted. Is recognized as an increase in the delay in the network corresponding to the time from the occurrence of transmission to the actual transmission, and a decrease in the stability of communication.

  In a decentralized wireless communication network that is built from the bottom up and emphasizes extensibility and compatibility with existing Ethernet (registered trademark), etc. (for example, in violation of a predetermined protocol (communication protocol)) A communication terminal that wirelessly communicates with a signal strength stronger than other communication terminals and a communication terminal that wirelessly transmits frequently secures more communication resources. As a result, a phenomenon that many other communication terminals (which comply with the above-mentioned rules) cannot secure communication resources is likely to occur, and measures to prevent this are also required.

  In addition, in a wireless communication network (for example, a mobile phone network) that can be constructed and managed in detail by a single carrier, everything including the allocation of communication resources is placed under the management of the carrier. It should be easy to ensure the fairness of resource utilization and control so that the overall allocation of communication resources is almost optimal. However, even in such a wireless communication network, when a third party irrelevant to the carrier operates a simple repeater having only an amplification function, more communication is performed through the repeater. Since a communication resource is secured and a phenomenon that many other communication terminals (which comply with the above-mentioned rules) cannot secure the communication resource is likely to occur, a countermeasure for preventing this phenomenon is required.

  In order to solve such a problem, in the first aspect of the present invention, as a result of executing access control between a plurality of communication terminals according to a predetermined transmission medium access control method, one or more communication terminals access the transmission medium. In a wireless communication system that performs wireless communication with a base station, the base station communicates with each communication terminal based on relay control information obtained from one of the communication terminals and / or actually measured values obtained by itself. The relay control unit includes a relay control unit that changes the content of the relay operation of the transmitted terminal transmission signal directly or indirectly through the operation of the communication terminal.

  In the second aspect of the present invention, as a result of performing access control between a plurality of communication terminals in accordance with a predetermined transmission medium access control scheme, one or a plurality of communication terminals access a transmission medium and perform wireless communication. In a base station as a component of a communication system, relay of terminal transmission signals wirelessly transmitted by each communication terminal based on relay control information obtained from any one of the communication terminals and / or measured values acquired by itself It is characterized by comprising a relay control unit that changes the content of the operation directly or indirectly through the operation of the communication terminal.

  Further, in the third aspect of the present invention, as a result of performing access control between a plurality of communication terminals according to a predetermined transmission medium access control method, one or a plurality of communication terminals access a transmission medium and perform wireless communication. In a communication terminal as a component of a communication system, (1) a contention detection unit that detects another terminal transmission signal wirelessly transmitted by another communication terminal competing for access to the transmission medium and obtains detection information as a detection result; (2) Analyzing the detection information obtained by the contention detection unit and identifying the base station that relays the other terminal transmission signal; and (3) the relay control information according to the detection information. Is provided with a first relay control information transmission unit that transmits to the base station specified by the signal analysis unit.

  Furthermore, in the fourth aspect of the present invention, as a result of executing access control between a plurality of communication terminals in accordance with a predetermined transmission medium access control method, one or a plurality of communication terminals access the transmission medium and execute wireless communication. In a communication terminal as a component of a wireless communication system, (1) a base station specifying unit that specifies a base station that relays a terminal transmission signal transmitted by itself, and (2) when transmitting the terminal transmission signal from itself A second relay control information transmitting unit that measures the signal strength and transmits the measured result as relay control information to the base station specified by the base station specifying unit; and (3) a terminal that arrives from the base station And a signal strength control unit that controls a signal strength when transmitting the terminal transmission signal according to control information.

  ADVANTAGE OF THE INVENTION According to this invention, the fairness of utilization of a communication resource can be improved.

(A) Embodiment Hereinafter, an embodiment will be described by taking as an example a case where the wireless communication system, the base station, and the communication terminal according to the present invention are applied to a communication system in which a repeater installed by a third party is mixed.

  This embodiment proposes a new communication protocol. This communication protocol is called a fairness ensuring protocol.

  This fairness ensuring protocol mainly corresponds to the layer below the data link layer in the OSI reference model. Although details will be described later, the fairness ensuring protocol is basically a competitive communication protocol similar to CSMA / CA. Therefore, it has high compatibility with Ethernet etc. and high expandability. It is also suitable for constructing an equally distributed communication environment.

  Regarding the fairness ensuring protocol, points that are not particularly mentioned in the following description may be the same as, for example, control in a normal mobile phone network or CSMA / CA.

(A-1) Configuration of the First Embodiment FIG. 3 shows an example of the overall configuration of the communication system 10 according to the present embodiment.

  In FIG. 3, the communication system 10 includes a repeater 11, base stations 12 and 15, and end terminals 13 and 14.

  The repeater 11, the base stations 12, 15 and the end terminals 13, 14 are all communication devices that communicate using radio.

  Among these, the end terminals 13 and 14 are communication apparatuses that are destinations or transmission sources of predetermined protocol data units (here, packets). Specifically, the end terminal (for example, 13) may be a notebook personal computer or the like, but here it is assumed to be a mobile phone. The end terminal 13 is used by the user U13, and the end terminal 14 is used by the user U14.

  The base station 12 is a communication device having a function of receiving and relaying packets transmitted from these end terminals. The interface on the end terminal 13 side of the base station 12 corresponds to the wireless communication function, but may have an interface corresponding to the wired communication function on the other side. When the base station is a base station of a mobile phone network, an interface corresponding to the wired communication function is usually mounted on the other side.

  The base station 15 is the same communication device as the base station 12. The communication between the base stations 12 and 15 may be executed via a control station (not shown) that accommodates the base stations 15 and 12, but here, the base stations 12 and 15 are directly connected. Shall be executed between. At this time, an interface corresponding to the wired communication function may be used. Since the base stations 12 and 15 are communication devices that are installed and operated by a communication carrier (here, a mobile phone carrier), the functions thereof are under the control of the communication carrier.

  The repeater 11 is a communication device for relaying a packet after performing amplification or the like, and is installed and operated by a third party unrelated to the communication carrier. The repeater 11 basically has only a function of amplifying and relaying a packet. This amplification is for relaying by transmitting with a signal strength stronger than the signal strength when the repeater 11 receives. In this amplification, the degree of amplification may be a constant value, and the signal intensity obtained as a result of amplification may be a constant value (amplification upper limit value). However, the problems described below mainly occur when the amplification degree is a constant value or when the amplification upper limit value is high (compared to a prescribed signal intensity described later).

  Here, the packet transmitted from the end terminal 13 is referred to as PK13, and the packet transmitted from the end terminal 14 is referred to as PK14. In the configuration of FIG. 1, the packet PK13 is relayed by the repeater 11. The packet after this relay is referred to as PK13T in order to distinguish it from the PK13.

  Note that these packets PK13 and PK14 are user packets that contain user data (such as voice data related to the voice spoken by the user) transmitted from the end terminals 13 and 14. In this embodiment, in addition to a user packet, a control packet containing control data is also transmitted. The control packet is transmitted through a transmission path (control channel) different from the user channel for transmitting the user packet. The final destination of the user packet may be 13 or 14, but is generally another mobile phone not shown in FIG.

  There can be various methods for dividing the transmission path of the user channel and the control channel. For example, the user channel and the control channel can be separated by using different frequencies.

  In the present embodiment, a violation investigation request packet VR1 and a signal strength control packet SC1, which will be described later, are used as control packets.

  The internal configuration of the end terminal 14 is as shown in FIG. The internal configuration of other end terminals 13 is the same as this.

(A-1-1) Internal Configuration Example of End Terminal In FIG. 1, the end terminal 14 includes a transmission control unit 20, a reception control unit 21, a contention detection unit 22, and an RF (high frequency) unit 23. ing.

  Of these, the RF unit 23 is a part that performs transmission and reception of radio signals (packets), and includes a carrier sense unit 23A and a signal demodulation unit 23B.

  The carrier sense unit 23A is a part that detects a carrier (carrier wave) from a radio transmission path (here, the user channel). A carrier transmitted by the end terminal 14 itself can be detected, and a carrier transmitted by another terminal (for example, 14, 11 or the like) can also be detected. However, in the case of wireless, it is easy to detect a carrier transmitted from a terminal located in the vicinity of the end terminal 14 itself, but it is difficult to detect a carrier transmitted from a terminal located far away. This is because the reception level of the carrier rapidly decreases as the distance to the terminal increases. In particular, it is practically impossible to detect a carrier transmitted by a distant terminal when the end terminal 14 is wirelessly transmitting.

  The signal demodulator 23B is a part that executes demodulation when receiving a radio signal (packet).

  The transmission control unit 20 is a part that controls the RF unit 23 when transmitting the packet (PK14). If the packet PK14 to be transmitted is generated inside the end terminal 14, for example, is it transmitted immediately and if a collision is detected, is transmission stopped and retransmitted after a random time has elapsed (collision detection transmission process)? Whether or not a collision will occur in advance is predicted for a predetermined collision detection time, and if the occurrence of a collision is predicted, the prediction is made again after the transmission of the packet is stopped (collision avoidance transmission processing), etc. Execute control.

  Since the RF unit 23 includes the carrier sense unit 23A, the result of carrier sense can be reflected in the collision detection transmission process or the collision avoidance transmission process.

  The reception control unit 21 receives a radio signal demodulation result (packet) and carrier sense result via the RF unit 23, and if necessary, receives the signal from the competition detection unit 22 and the received signal. This is a part to be supplied to the transmission control unit 20.

  The contention detection unit 22 collects and analyzes packets and the like flowing in the user channel based on the signal received from the reception control unit 21, and the sniff unit 22A on the user channel based on the result of the analysis. A conflict detection execution unit 22B that detects that a conflict has occurred is provided.

  The sniff unit 22A functions when the user channel cannot be used due to collision (detection or prediction) (that is, when the packet PK14 cannot be transmitted).

  When a packet transmitted from a transmission source other than the end terminal 14 is detected as a result of the function of the sniff unit 22A, the transmission source of the packet is the upper limit of the signal strength at the time of transmission defined by the fairness ensuring protocol. There is a possibility that wireless transmission is being performed with an intensity that is too strong to violate the value (specified signal intensity). The sniff unit 22A also examines an address (a transmission source address (for example, a transmission source MAC address or a transmission source IP address) or a destination address) that uniquely specifies a transmission source or a destination included in the header of the packet. The transmission source terminal can be specified. The source terminal may be one of end terminals (for example, 13) or one of repeaters (here, 11).

  Here, the address of the end terminal 14 is M14. Similarly, the address of the end terminal 13 is M13. Further, the address of the base station 12 is M12, and the address of the base station 15 is M15.

  Packets transmitted from various terminals in the communication system 10 may cause a collision and may be analyzed by the sniff unit 22A. In the following description, it is assumed that the analyzed packet is PK13T. .

  The sniff unit 22A can also specify the address M13 of the terminal 13 that is the original transmission source of the analyzed packet by reading the description of the transmission source address of the packet PK13T.

  Thereby, the sniff unit 22A transmits the violation investigation request packet VR1 via the transmission control unit 20.

  The violation investigation request packet VR1 is transmitted to the base station 12 that is the destination of the analyzed packet PK13T as to whether or not the end terminal 13 that is the original transmission source of the analyzed packet PK13T complies with the specified signal strength described above. Depending on the result of the survey, it may be meaningful to request that control be performed to improve the current situation.

  If the prescribed signal strength is observed, there is a high possibility that the violation investigation request packet VR1 cannot be directly delivered from the end terminal 14 to the base station 12, so that the violation investigation request packet VR1 is transmitted to the nearest base station ( In the example of FIG. 3, it is delivered via 15).

  On the other hand, the internal configuration of the base station 12 is as shown in FIG. The internal configuration of the base station 15 is the same as this.

(A-1-2) Example of Internal Configuration of Base Station In FIG. 2, the base station 12 includes a transmission control unit 30, a reception control unit 31, a relay contention detection unit 32, an RF unit 33, and relay resource management. Part 34. The RF unit 33 includes a carrier sense unit 33A and a signal demodulation unit 33B.

  Among them, the RF unit 33 corresponds to the RF unit 23, the carrier sense unit 33A corresponds to the carrier sense unit 23A, the signal demodulation unit 33B corresponds to the signal demodulation unit 23B, and the transmission control unit 30 performs the transmission control. Since the reception control unit 31 corresponds to the reception control unit 21 and the relay contention detection unit 32 corresponds to the contention detection unit 22, detailed description thereof is omitted.

  However, the reception control unit 31 includes a signal intensity measurement unit 31A and a suitability determination unit 31B.

  When the violation investigation request packet VR1 addressed to itself is received, the transmission control unit 30 of the base station 12 transmits the signal strength control packet SC1 to the end terminal 13 that is the original transmission source of the packet PK13T. . This signal strength control packet SC1 is meaningful to instruct the end terminal, which is the original transmission source, to comply with the prescribed signal strength.

  The signal strength actual measurement unit 31A is a part that actually measures the signal strength at the time of receiving a packet in order to confirm whether or not the end terminal 13 that has transmitted the signal strength control packet SC1 complies with the instruction. The packet to be actually measured is PK13P. The packet PK13P is the same as the packet PK13T in that it is a packet after the repeater 11 relays the packet PK13 transmitted from the end terminal 13, but the base station 12 after transmitting the signal strength control packet SC1. The difference is that it is a packet that has arrived.

  The suitability determination unit 31B estimates the signal strength when transmitted from the end terminal 13 based on the actual measurement result of the signal strength actual measurement unit 31A, and determines whether the signal strength conforms to the specified signal strength. That is, it is a part for determining whether or not the end terminal 13 has followed the instruction made in the signal strength control packet SC1.

  The relay resource management unit 34 is a part that manages the relay resources (for example, CPU (central processing unit) processing capacity, buffer storage capacity, etc.) used by the base station 12 for relaying the packet PK13P. is there. When the suitability determination unit 31B determines that the end terminal 13 does not comply with the instruction, the packet PK13P transmitted from the end terminal 13 and currently subjected to relay processing by the base station 12 is transmitted. Reduce the amount of relay resources used for relay processing. If possible, not only the quantity but also the quality of the relay resource may be reduced.

  For example, if the amount of CPU processing capacity used for the packet PK13P (the time for allocating the CPU for the relay processing of the packet PK13P) is reduced, the base station 12 needs to relay the packet PK13P. The time is increased, and this is recognized by the end terminal 13 (or the end terminal that is the communication partner) as a decrease in communication speed or throughput. Further, if the buffer storage capacity used for the packet is reduced, a buffer overflow is likely to occur, and this is recognized by the end terminal 13 (or the end terminal that is the communication partner) as a reduction in communication quality.

  The operation of the present embodiment having the above configuration will be described below.

(A-2) Operation of the First Embodiment In the configuration of FIG. 3, as described above, the packet PK14 wirelessly transmitted from the end terminal 14 to the desired end terminal is applicable via the relay by the base station 15 or the like. To the end terminal. Similarly, the packet PK13 wirelessly transmitted from the end terminal 13 to the desired end terminal is delivered to the corresponding end terminal via relaying by the repeater 11 and the base station 12 or the like. As described above, the packets PK13 and PK14 are transmitted using the user channel.

  However, the contention detection execution unit 22B of the end terminal 14 that intends to transmit the packet PK14 may detect (or predict the occurrence of contention) that contention has occurred on the user channel. When this detection (or prediction) is performed, transmission of the packet PK14 is temporarily suspended regardless of whether the collision detection transmission process or the collision avoidance transmission process is performed, and at least competition is detected (prediction). The packet PK14 cannot be transmitted until it is not transmitted.

  When the conflict is detected (predicted), the sniff unit 22A of the end terminal 14 determines the initial of the packet PK13T from the description of each field in the header of the packet PK13T based on the detection (prediction). Is the end terminal 13 (address M13), and the base station that relays to the destination is the base station 12.

  Then, the violation investigation request packet VR1 reflecting the identified result is transmitted. Even if contention occurs on the user channel, since the control channel is a transmission path physically different from the user channel, the violation investigation request packet VR1 can be normally transmitted. is there.

  The violation investigation request packet VR1 transmitted from the end terminal 14 reaches the destination base station 12 via the base station 15.

  Receiving this, the base station 12 transmits the signal strength control packet SC1 destined for the end terminal 13. Since the signal strength control packet SC1 is also transmitted using the control channel, it is normally delivered to the end terminal 13 via the repeater 11.

  Since the time from when the base station 12 receives the violation investigation request packet VR1 to when the signal strength control packet SC1 is transmitted is short, in many cases, even after the signal strength control packet SC1 is transmitted Transmission of the packet PK13 (PK13P) by the terminal 13 is repeated.

  Therefore, in the base station 12, when the packet strength control packet SC1 is received after being transmitted and the packet PK13P whose initial transmission source is the end terminal 13 is received, the signal strength measurement unit 31A measures the signal strength. can do. Based on the actual measurement result, the suitability determination unit 31B operates to check whether or not the end terminal 13 complies with the specified signal strength as instructed by the signal strength control packet SC1.

  When the inspection result that is compliant is obtained, sufficient relay resources are allocated for the packet PK13P as usual, but the inspection result that is not compliant is described above. As described above, the amount of the relay resource used for relaying the packet PK13P is reduced.

  As a result, a decrease in communication speed, throughput, and communication quality is recognized on the end terminal 13 side or the end terminal side that is the communication partner, so that the user U13 or the like can be guided in a direction to comply with the specified signal strength. it can. Such control can be said to be a kind of sanctions, but for example, since it is more gradual than the case of immediately refusing to relay the packet PK13P, the stability of the communication from which the end terminal 13 is a transmission source. Will not be greatly impaired.

  If the user U13 comes to comply with the prescribed signal strength, the geographical area where contention occurs on the user channel is narrowed. Therefore, the end terminal used by the user U14 who originally complies with the prescribed signal strength 14, the contention is less likely to be detected (predicted), and the end terminal 14 can also secure communication resources for itself (in this case, the frequency resource at the location where the end terminal 14 is located corresponds to the communication resource). The packet PK14 can be transmitted promptly.

  Here, attention is paid only to the direction transmitted from the end terminal 13, but actual communication is often not bidirectional communication but bidirectional communication. In the case of bidirectional communication, for example, when the end terminal 13 does not follow the instruction by the signal strength control packet SC1, it is a packet (user packet) transmitted by the end terminal that is the communication partner of the end terminal 13. In addition, the amount of relay resources used in the base station 12 may be reduced.

  Further, although the end terminal 13 actually observes the prescribed signal strength, the violation investigation request packet VR1 is caused by a cause on the end terminal 14 side (for example, an unexpected failure or an intentional DoS attack). Since it may be transmitted, the unjustness in that case can be alleviated by using the above-mentioned gradual one as the sanctions.

  In any case, in the present embodiment, by interposing the repeater 11, a state in which any end terminal has secured more communication resources than originally allocated from the base station 12, is reported, By investigating and disposing, the use of the repeater 11 can be suppressed, the effectiveness of communication resource management by the base station 12 can be maintained, and the fairness of the use of communication resources can be enhanced.

(A-3) Effect of First Embodiment According to the present embodiment, the basic mechanism (competitive medium access method) in which each end terminal tries to secure communication resources on its own is determined by itself. A specific end terminal (for example, 13) secures an excessive amount of communication resources by ensuring the control of the base station (12) that attempts to equalize the provision of communication resources and make the provision of relay opportunities fair for all communications related to the relay. Therefore, it is possible to increase the fairness of communication resource use.

  Thereby, as a whole communication system (10), the allocation of communication resources to each end terminal (13, 14) can be brought close to an optimum one.

  This also means that when viewed from the individual end terminals, even if the total amount of communication resources in the communication system (10) is the same, the communication speed and throughput increase, the delay in the network decreases, and the communication stability Is recognized as an increase.

(B) Second Embodiment Hereinafter, only differences between the present embodiment and the first embodiment will be described.

(B-1) Configuration and operation of the second embodiment The configuration is different from the first embodiment only in respect of the internal configurations of the end terminals 13 and 14 and the base stations 12 and 15. It is done.

  The internal configuration of the end terminal 14 of this embodiment is as shown in FIG. 4, for example.

  In FIG. 4, since the function of the component which gave the same code | symbol as FIG. 1 is the same as 1st Embodiment, the detailed description is abbreviate | omitted. The point that the other end terminal 13 has the same internal configuration as the end terminal 14 is the same as that of the first embodiment.

  The transmission control unit 20 shown in FIG. 4 includes a transmission signal strength description unit 20A and a transmission signal strength control unit 20B therein.

  Among these, the transmission signal strength description unit 20A transmits the transmission signal strength (packet from the end terminal 14) to the base station (for example, 12) in the corresponding field (transmission signal strength declaration field) in the header of the packet PK14. (Signal strength when wirelessly transmitting PK14) is described. Therefore, all the user packets in this embodiment include the transmission signal strength report field in the header.

  Normally, the transmission signal strength description unit 20A describes the true transmission signal strength in the transmission signal strength description field. However, in rare cases, the transmission signal strength description field may describe a disguised transmission signal strength different from the actual transmission signal strength. The problem in the configuration of the present embodiment is when a transmission signal strength smaller than the actual one is described.

  The transmission signal strength control unit 20B is a part that lowers the transmission signal strength according to an instruction when a lowering request packet DR1 described later arrives.

  However, in the case of an end terminal that describes the disguised transmission signal strength in the transmission signal strength declaration field, the transmission signal strength control unit 20B is modified so as not to follow the instruction of the reduction request packet DR1. There is a possibility that the transmission signal strength control unit 20B itself is deleted and does not exist.

  On the other hand, the internal configuration of the base station 12 of this embodiment is as shown in FIG. 5, for example.

  In FIG. 5, since the function of the component which gave the same code | symbol as FIG. 2 is the same as 1st Embodiment, the detailed description is abbreviate | omitted. The point that the other base station 15 has the same internal configuration as the base station 12 is the same as in the first embodiment.

  The constant signal strength measurement processing unit 31C included in the reception control unit 31 shown in FIG. 5 measures the signal strength when an end terminal (for example, 13) receives a packet that is a transmission source. Although it is the same as the actual measurement unit 31A, the constant signal strength actual measurement processing unit 31C always receives a packet (here, PK13H) regardless of whether or not the signal strength control packet SC1 is transmitted. Is actually measured, and it is determined whether the actual measurement result is excessive compared to the content (declared value) described in the transmission signal strength declaring field in the header of the packet PK13H.

  In the present embodiment, the user packet transmitted from the end terminal 13 is PK13J. The packet after the relay device 11 relays the packet PK13J is the packet PK13H. The packets PK13J and PK13H differ from the packets PK13 and PK13T only in that the transmission signal strength declaration field is present in the header.

  As a result of the determination, when it is determined that the constant signal strength actual measurement processing unit 31C is excessive, the reduction request packet DR1 is transmitted to the end terminal 13. The reduction request packet DR1 is a control packet that requests the transmission signal strength control unit 20B in the end terminal 13 to reduce the signal strength at the time of wireless transmission in the end terminal 13.

  However, for example, the signal strength described in the transmission signal strength report field is determined to be excessive because the signal strength is too weak compared to the prescribed signal strength, and the signal strength is less than the prescribed signal strength at the time of transmission in the actual end terminal 13. When it is clear that there is, it is possible not to transmit the reduction request packet DR1. In that case, the end terminal 13 may be instructed to optimize the description of the transmission signal strength report field.

  Although the signal strength described in the transmission signal strength declaration field of the packet PK13H transmitted from the end terminal 13 after transmitting the lowering request packet DR1 is reduced, the constant signal strength actual measurement process If the actual measurement result by the unit 31C has not decreased, the specified signal strength may be violated as a result of amplification by the intervening repeater (11 in the example of FIG. 3). A control packet (relay change packet) is transmitted to the end terminal 13.

  When the end terminal 13 that has received the notification notifies the user U13 of the fact, the user U13 can try communication without going through the repeater 11 by moving the end terminal 13, for example.

  If the same situation continues even after a predetermined time (or a predetermined number of packets) has elapsed after transmission of the relay change packet, the base station 12 uses the end signal in the transmission signal strength declaration field of the packet PK13H. By wirelessly transmitting at the same signal strength as the signal strength reported by 13, a user packet addressed to the end terminal 13 (for example, a packet received from an end terminal of a communication partner not shown) is relayed.

  If the signal strength when actually transmitted from the end terminal 13 is the same as the value declared in the transmission signal strength declaration field, the communication resource by the repeater 11 that wirelessly transmits to relay the user packet The user packet is quickly delivered to the end terminal 13, but if the value exceeds the value reported in the transmission signal strength report field, the end terminal 13 itself uses communication resources. The relay 11 cannot secure communication resources because it is secured excessively, and the user packet does not reach the end terminal 13 or arrives late.

  This is a sanctions for declaring a signal strength that is smaller than the actual one, and it is possible to report the correct signal strength and guide the user U13 in the direction of complying with the prescribed signal strength.

  In the present embodiment, the end terminal 13 actually observes the prescribed signal strength, but other causes (for example, when the amplification degree in the repeater 11 is too large, or the signal strength actual measurement processing unit If the constant signal strength measurement processing unit 31C transmits the lowering request packet DR1 due to incomplete determination by 31C or the like, the end terminal 13 is not disadvantaged at all. This eliminates the risk of improper handling based on incorrect control.

(B-2) Effect of Second Embodiment According to the present embodiment, an effect equivalent to the effect of the first embodiment can be obtained.

  In addition, in the present embodiment, the wireless transmission for relaying to a certain end terminal (for example, 13) is performed with the signal strength that the end terminal has declared, so that the wrong handling is performed based on erroneous control. The risk of carrying out can be eliminated. This also contributes to maintaining fair use of communication resources.

(C) Other Embodiments The present invention is naturally applicable to a communication system having a configuration other than that shown in FIG. For example, the number of repeaters included in the communication system is not limited to one illustrated, and may be two or more. Similarly, the number of end terminals and base stations need not be limited to the two illustrated. When there are two or more repeaters, one packet transmitted from the end terminal may be delivered to the base station via a plurality of repeaters.

  In the first embodiment, only resources existing in the base station (for example, CPU processing capacity, buffer storage capacity, etc.) are exemplified as relay resources. However, they exist outside the base station. The resource to be used can be used as a relay resource. For example, the signal strength of radio transmission for the relay (which corresponds to the area of the geographical area where the corresponding frequency resource is secured) can be included in the relay resource.

  In addition, the second embodiment has the features of the first embodiment, but the end terminal that is the feature of the second embodiment makes it possible to report the signal strength at the time of transmission, and the declared value. Since the control is executed by comparing the measured value with the actual measurement value in the base station, it is independent of the features of the first embodiment, so only the features of the second embodiment are applied to the communication system alone. Of course you can do it.

  Further, in the second embodiment, the base station (12), the content of the actual measurement result of the signal strength of the received packet (PK13H) described in the transmission signal strength declaration field in the header of the packet PK13H ( It is determined whether it is not excessive compared to the reported value), but it is also easy to set a fixed value to be compared with the actual measurement result. In this case, the fixed value may be the prescribed signal strength. In this case, the signal strength when the user packet addressed to the end terminal (13) is wirelessly transmitted from the base station 12 after the predetermined time (predetermined number of packets) may be the same as the fixed value. .

  Regardless of the first and second embodiments, the control information unique to each embodiment may be transmitted by a method other than that described in the header of the packet. For example, the declared value for declaring the signal strength when the packet (PK13J) is transmitted to the end terminal is not a transmission signal strength declaring field included in the header of the packet PK13J, but is transmitted almost simultaneously on the control channel. You may make it transmit with a packet.

  The present invention can also be applied to so-called ad hoc networks.

  Further, the present invention is naturally applicable to an equal distributed communication system such as a wireless LAN. In that case, a new end terminal (such as a notebook personal computer equipped with a wireless LAN card) or a repeater somewhere in the communication system (for example, 10) or a repeater (in an ad hoc network, the end terminal itself has a relay function as a repeater. Even if the existing end terminals and repeaters are deleted, no special maintenance or configuration changes are required, and the scalability is high. In addition, it has high compatibility with existing Ethernet.

  Note that the fairness ensuring protocols shown in the first and second embodiments have high compatibility with Ethernet, CSMA / CA, etc., so that it is possible to extend the existing CSMA / CA according to the present invention. is there. In this implementation, there is a high possibility that a hardware module or software module for processing existing CSMA / CA can be used as it is.

  In the above description, most of the functions realized in hardware can be realized in software, and almost all the functions realized in software can be realized in hardware.

It is the schematic which shows the structural example of the principal part of the end terminal used by 1st Embodiment. It is a structural example of the principal part of the repeater used in 1st Embodiment. It is the schematic which shows the example of whole structure of the communication system concerning 1st, 2nd embodiment. It is a structural example of the principal part of the end terminal used by 2nd Embodiment. It is a structural example of the principal part of the repeater used in 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Communication system, 11 ... Repeater, 12, 15 ... Base station, 13, 14 ... Communication terminal, PK13, PK14 ... Packet.

Claims (10)

As a result of executing access control between a plurality of communication terminals according to a predetermined transmission medium access control method, in a wireless communication system in which one or a plurality of communication terminals access a transmission medium and perform wireless communication with a base station,
The base station
Based on the relay control information obtained from any one of the communication terminals and / or the actual measurement value acquired by itself, the content of the relay operation of the terminal transmission signal wirelessly transmitted by each of the communication terminals, Alternatively, a wireless communication system comprising a relay control unit that changes indirectly through the operation of the communication terminal. The wireless communication system of claim 1.
The communication terminal is
A conflict detection unit that detects other terminal transmission signals wirelessly transmitted by other communication terminals competing for access to the transmission medium and obtains detection information as a detection result;
Analyzing the detection information obtained by this contention detection unit, a signal analysis unit for identifying the base station that relays the other terminal transmission signal,
A first relay control information transmission unit that transmits the relay control information according to the detection information to the base station identified by the signal analysis unit;
The base station
When receiving the relay control information addressed to itself, according to the relay control information, a first relay processing resource control unit that controls the amount of relay processing resources to be secured for relaying the other terminal transmission signal, A wireless communication system comprising the relay control unit. The wireless communication system of claim 1.
The communication terminal is
A base station identifying unit that identifies a base station that relays the terminal transmission signal transmitted by itself;
A second relay control information transmitting unit that measures the signal strength when transmitting the terminal transmission signal from itself and transmits the measured result to the base station specified by the base station specifying unit as the relay control information When,
In accordance with the terminal control information received from the base station, comprising a signal strength control unit for controlling the signal strength when transmitting the terminal transmission signal,
The base station
A reception intensity measurement unit that actually measures the signal intensity of the terminal transmission signal received for relaying;
Terminal control for requesting the communication terminal to lower the signal strength at the time of transmitting the terminal transmission signal from the current value when the actual measurement result by the reception strength actual measurement unit shows a value larger than a predetermined reference value. A wireless communication system comprising: a terminal control information transmission unit that transmits information as the relay control unit. The wireless communication system of claim 3,
The reference value is
The wireless communication system, wherein the base station has signal strength acquired as the relay control information. The wireless communication system of claim 3,
The base station
Based on the actual measurement result of the reception strength actual measurement unit and the actual measurement result received from the communication terminal as the relay control information, the optimum transmission strength for calculating the optimum signal strength when transmitting the terminal transmission signal in the communication terminal With a calculator
A wireless communication system, wherein the terminal control information transmitting unit transmits the optimum signal strength calculated by the optimum transmission strength calculating unit as the terminal control information. The wireless communication system of claim 5,
The base station
Based on the actual measurement result of the reception strength actual measurement unit and the actual measurement result received from the communication terminal as the relay control information, the signal strength at the time of transmitting the terminal transmission signal in the communication terminal is already in the communication terminal. A signal strength compatibility determination unit that determines the degree of matching with the transmitted optimal signal strength;
And a second relay processing resource control unit that controls the amount of relay processing resources to be secured for relaying the terminal transmission signal according to the determination result of the signal strength suitability determining unit. Wireless communication system. The wireless communication system of claim 3,
The base station
A transmission signal strength control unit that performs wireless transmission to a communication terminal that is a transmission source of the relay control information with a signal strength corresponding to an actual measurement result received as the relay control information,
If the communication terminal transmits an actual measurement result smaller than the actual value as relay control information by camouflaging, it is difficult to receive via the base station. As a result of executing access control between a plurality of communication terminals according to a predetermined transmission medium access control method, a base station as a component of a wireless communication system in which one or a plurality of communication terminals access a transmission medium and perform wireless communication In
Based on the relay control information obtained from any one of the communication terminals and / or the actual measurement value acquired by itself, the content of the relay operation of the terminal transmission signal wirelessly transmitted by each of the communication terminals, Alternatively, a base station comprising a relay control unit that changes indirectly through the operation of the communication terminal. As a result of executing access control between a plurality of communication terminals according to a predetermined transmission medium access control method, a communication terminal as a component of a wireless communication system in which one or a plurality of communication terminals access a transmission medium and perform wireless communication In
A conflict detection unit that detects other terminal transmission signals wirelessly transmitted by other communication terminals competing for access to the transmission medium and obtains detection information as a detection result;
Analyzing the detection information obtained by this contention detection unit, a signal analysis unit for identifying the base station that relays the other terminal transmission signal,
A communication terminal comprising: a first relay control information transmission unit that transmits the relay control information corresponding to the detection information to a base station specified by the signal analysis unit. As a result of executing access control between a plurality of communication terminals according to a predetermined transmission medium access control method, a communication terminal as a component of a wireless communication system in which one or a plurality of communication terminals access a transmission medium and perform wireless communication In
A base station identifying unit that identifies a base station that relays a terminal transmission signal transmitted by itself;
A second relay control information transmitting unit that measures the signal strength when transmitting the terminal transmission signal from itself, and transmits the measured result as relay control information to the base station identified by the base station identifying unit; ,
A communication terminal comprising: a signal strength control unit that controls signal strength when transmitting the terminal transmission signal in accordance with terminal control information received from the base station.

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