Wireless communication system, wireless communication device and wireless communication method, and computer program

• US 20050169232A1
• Filed: 10/25/2004
• Published: 08/04/2005
• Est. Priority Date: 10/24/2003
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sakoda, Kazuyuki, Iwami, Hideki, Nishikawa, Kenzo
• Granted Patent: US 8,428,041 B2
• Time in Patent Office: Days
• US Class Current: 370/347
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/1628 List acknowledgements, i.e. the acknowledgement message consisting of a list of identifiers, e.g. of sequence numbers H04L1/1614 takes precedence
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04L 43/0823 Errors, e.g. transmission errors
• CPC Class Codes: H04L 43/0894 Packet rate
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

Access control based on CSMA is favorably carried out with the RTS/CTS method used together. If the RTS/CTS procedure is used together, CTS information is transmitted in response to the reception of RTS information, and data is transmitted in response to the reception of CTS. The CTS transmitting station measures the quality of RTS receive signal, and thereby determines a transmission rate at which it can receive and notifies a station as the destination of CTS. The station as the destination of CTS transmits data in response to CTS information. As the transmission rate for this data, the transmission rate indicated in the RATE field in CTS is applied.

Claims

1. A wireless communication system in which random access is made concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS (Request To Send) and starts data transmission in response to the reception of a response packet CTS (Clear To Send) from a communication station as the destination of data transmission,

wherein the RTS receiving communication station measures the quality of receive signal, determines a data rate based on the result of the measurement, describes the data rate in a CTS, and transmits the CTS, and

wherein the CTS receiving communication station carries out data transmission as the outcome of the reception of the CTS information based on the data rate described in the CTS.

2. The wireless communication system according to claim 1,

wherein the RTS transmitting communication station describes in RTS the time that lapses before the reception of a packet containing the CTS information, transmitted as the outcome of the reception of RTS information, as medium reservation time information,

wherein the CTS transmitting communication station describes in CTS the time that lapses before the reception of a data packet, transmitted as the outcome of the reception of CTS information, as medium reservation time information, and

wherein other communication stations which receive RTS or CTS set a NAV (Network Allocation Vector), and keep it effective and other communication stations themselves in transmission prohibited state over the duration of the medium reservation time information.

3. The wireless communication system according to claim 1,

wherein the RTS transmitting communication station describes in RTS factor information which is referred to by the RTS receiving communication station when it determines a data rate, and

wherein the RTS receiving communication station takes into account the factor information described in the RTS in addition to the result of the measurement of receive signal quality when it determines a data rate.

4. The wireless communication system according to claim 3,

wherein as said factor information, information related to whether to aggressively determine a high data rate or passively determine a low data rate is described, and

wherein the RTS transmitting communication station determines factor information based on at least one of the transmission error rate for the RTS receiving communication station, the difference in transmission power between RTS packet and data packet, and the causal relationship between data rate and transmission power.

5. The wireless communication system according to claim 1,

wherein the RTS transmitting communication station describes in RTS information related to one or more data units it tries to transmit, and

wherein the RTS receiving communication station determines the medium reservation time information in the duration of which the reception of all the data packets is completed based on the information related to the data units described in the RTS and the determined data rate, and describes the determined medium reservation time information in CTS.

6. The wireless communication system according to claim 5,

wherein the CTS receiving communication station carries out data transmission as the outcome of the reception of CTS information based on the data rate described in the CTS so that the transmission is completed within the time specified by the medium reservation time information.

7. The wireless communication system according to claim 5,

wherein the information related to data units is the data length of each data unit for which transmission is tried.

8. The wireless communication system according to claim 5,

wherein the information related to data units is the sum of the data lengths of one or more data units for which transmission is tried.

9. The wireless communication system according to claim 5,

wherein the information related to data units is the time length required for transmitting one or more data units for which transmission is tried.

10. The wireless communication system according to claim 5,

wherein the information related to data units is information on the number of data units for which transmission is tried.

11. The wireless communication system according to claim 5,

wherein, when the RTS receiving communication station determines medium reservation time information after the reception of RTS, the station takes into account the time at which the station itself completes data reception.

12. The wireless communication system according to claim 5,

wherein the RTS transmitting communication station describes in RTS information on the period until the time until which the station itself can transmit, and

wherein the RTS receiving communication station gives consideration so that said information on the period described in the RTS is not exceeded when it determines medium reservation time information after the reception of RTS.

13. The wireless communication system according to claim 5,

wherein the RTS transmitting communication station assigns sequence numbers to transmit data units, describes in RTS the first sequence number of data it tries to transmit, and notifies of information related to the data units it tries to transmit, and

wherein the RTS receiving communication station refers to the first sequence number of data units described in the RTS, extracts data units already received from data units for which transmission is tried, excludes them from objects to be received, and then determines medium reservation time information.

14. The wireless communication system according to claim 13,

wherein, if selective acknowledgement is applied, the RTS transmitting communication station describes in RTS reception acknowledgement information containing the first sequence number of data units for which data transmission is tried and bit map information obtained by mapping the reception confirmation information on the subsequent data units into bits corresponding to the relative positions to the first sequence number, and further generates information related to said data units with only data units for which reception confirmation has not been obtained taken as objects to be transmitted, and

wherein, if selective acknowledgement is applied, the RTS receiving communication station refers to said bit map information described in the RTS, extracts data units it has already received from data units for which transmission is tried, excludes them from the objects to be received, and then determines medium reservation time information.

15. The wireless communication system according to claim 5,

wherein, if a data unit already received is included in the data units to be transmitted described in the RTS, the RTS receiving communication station describes ACK information in CTS.

16. The wireless communication system according to claim 5,

wherein the CTS receiving communication station excludes the data units already received by the RTS receiving communication station from the objects to be transmitted based on the ACK information added to the CTS, and carries out data transmission based on the data rate described in the CTS.

17. The wireless communication system according to claim 13,

wherein the RTS receiving communication station stores one or more pieces of data length information of data units to be received, of data for which transmission is tried as the outcome of the RTS, and describes in CTS the sequence number of the last data unit stored.

18. The wireless communication system according to claim 17,

wherein the CTS receiving communication station stores the sequence number of said last data unit described in the CTS, and generates information related to data units for which transmission is tried in such form that the data unit indicated by the sequence number of said last data unit is not included in objects to be transmitted when an RTS is transmitted next time.

19. A wireless communication system for transmitting and receiving a plurality of data units in which sequence numbers are assigned to transmit data units to identify the data units,

wherein, if selective acknowledgement is applied, the receiving communication station describes in reception acknowledgement information ACK the sequence numbers of completely received data units in the order of sequence number, and bit map information represented by mapping the state of reception of data of the subsequent sequence numbers into relative bit positions from the sequence numbers, and transmits the information,

wherein, if selective acknowledgement is applied, the receiving and transmitting communication stations add information indicating a causal data flow to transmit data and acknowledgement.

20. The wireless communication system according to claim 19,

wherein the receiver station which does not support selective acknowledgement transmits said bit map information with zero set for all the bits of the bit map field.

21. The wireless communication system according to claim 19,

wherein, with respect to at least one data flow, the ARQ system in which sequence numbers are not assigned is adopted, and, when Link session is established, data is transmitted and received through the data flow, and thereby the sequence numbers of the transmitter station and the receiver station are synchronized with each other.

22. A wireless communication system in which random access is made concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission,

wherein it is permitted to transmit and receive packets in which any two or more of request to send RTS, confirmative advice CTS, data, and acknowledgement ACK are multiplexed.

23. The wireless communication system according to claim 22,

wherein the communication station sets the time by which the other station'"'"'s transmission of a packet as the outcome of the transmission of a packet is completed, and describe it as medium reservation time information of the transmit packet.

24. The wireless communication system according to claim 22,

wherein the communication station which receives a packet containing RTS information transmits a packet containing CTS information in accordance with the contents of the RTS, and

wherein the communication station which receives a packet containing CTS information transmits a packet containing data in accordance with the contents of the CTS.

25. The wireless communication system according to claim 22,

wherein in the RTS, first information is described which indicates whether RTS information may be added to a CTS transmitted as the outcome of the RTS or not.

26. The wireless communication system according to claim 25,

wherein the RTS receiving communication station judges whether it may add RTS information to a packet returned or not, based on the first information in the RTS, and, if data of desiring to transmit to the RTS transmitting communication station is present, transmits a CTS to which RTS information is added for the purpose of transmitting the data or a packet containing RTS information for the purpose of transmitting the data.

27. The wireless communication system according to claim 25,

wherein the RTS receiving communication station, when a packet containing RTS information is received, and if data of desiring to transmit to the RTS transmitting communication station is present, transmits a CTS to which RTS information is added for the purpose of transmitting the data or a packet containing RTS information for the purpose of transmitting the data.

28. The wireless communication system according to claim 25,

wherein the RTS transmitting communication station determines first information based on information elements contained in the packets received from the station as the destination of the RTS in the past.

29. The wireless communication system according to claim 22,

wherein, if the RTS receiving communication station recognizes from the information in the RTS that the RTS transmitting communication station is trying to transmit data already received by the RTS receiving communication station, adds ACK information to the CTS.

30. The wireless communication system according to claim 22,

wherein, if the data receiving communication station receives data which requests an ACK from the data transmitting communication station and judges that it has not transmitted the ACK of the data, the data receiving communication station adds ACK information when it transmits a packet of some kind to the data transmitting communication station.

31. The wireless communication system according to claim 30,

wherein the data receiving communication station does not add ACK information to a packet in which RTS information is solely transmitted.

32. The wireless communication system according to claim 30,

wherein the communication station transmits data which requests an ACK in a packet directed to two or more communication stations.

33. The wireless communication system according to claim 22,

wherein the RTS transmitting communication station transmits to the RTS receiving communication station an RTS in which an ACK request for requesting a return of the ACK of data it has transmitted so far is multiplexed.

34. The wireless communication system according to claim 22,

wherein, if the RTS transmitting communication station failed to receive the ACK of data it has transmitted so far, it transmits to the RTS receiving communication station an RTS in which an ACK request for requesting a return of an ACK is multiplexed.

35. The wireless communication system according to claim 33 or 34,

wherein the communication station which receives the RTS with an ACK request multiplexed returns an ACK which indicates whether the reception of data transmitted from said RTS transmitting communication station has been completed or not, or, if it has failed to receive data transmitted from said RTS transmitting communication station, multiplexes a CTS which requests to retransmit the data and an ACK of the ACK request and returns them.

36. A wireless communication device which makes random access concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the wireless communication device comprising:

a communication quality measuring means which measures the quality of receive signal when an RTS is received;

a data rate determining means which determines a data rate based on the measured quality of receive signal; and

a CTS transmitting means which describes the data rate in CTS as the outcome of the received RTS and transmits the CTS.

37. The wireless communication device according to claim 36, further comprising:

an RTS transmitting means which transmits an RTS when the device requests data transmission; and

a data transmitting means which, based on the data rate described in the CTS when it receives CTS information, carries out data transmission as the outcome of the CTS information.

38. The wireless communication device according to claim 37,

wherein said RTS transmitting means describes in RTS the time that lapses before the reception of a packet containing CTS information, transmitted as the outcome of the reception of RTS information, as medium reservation time information, and transmits the RTS, and

wherein said CTS transmitting means describes in CTS the time that lapses before the reception of a data packet, transmitted as the outcome of the reception of CTS information, as medium reservation time information, and

wherein a transmission stopping means is further provided which, when the wireless communication device receives an RTS or a CTS not directed to itself, sets an NAV and keeps it effective and the wireless communication device itself in transmission prohibited state over the duration of medium reservation time information.

39. The wireless communication device according to claim 37,

wherein said RTS transmitting means describes in RTS factor information which is referred to by the RTS receiving communication station when it determines a data rate, and

wherein said data rate determining means takes into account the factor information described in the RTS in addition to the result of the measurement of receive signal quality when it determines a data rate.

40. The wireless communication device according to claim 39,

wherein said factor information is information related to whether to aggressively determine a high data rate or passively determine a low data rate, and

wherein said RTS transmitting means determines factor information based on at least one of the transmission error rate for the RTS receiving communication station, the difference in transmission power between RTS packet and data packet, and the causal relationship between data rate and transmission power.

41. The wireless communication device according to claim 37,

wherein said RTS transmitting means describes in RTS information related to one or more data units it tries to transmit, and

wherein said CTS transmitting means determines the medium reservation time information in the duration of which the reception of all the data packets is completed based on information related to the data units described in RTS and the determined data rate.

42. The wireless communication device according to claim 41,

wherein said data transmitting means carries out data transmission as the outcome of the reception of CTS information based on the data rate described in the CTS so that the transmission is completed within the time specified by the medium reservation time information.

43. The wireless communication device according to claim 41,

wherein the information related to data units is the data length of each data unit for which transmission is tried.

44. The wireless communication device according to claim 41,

wherein the information related to data units is the sum of the data lengths of one or more data units for which transmission is tried.

45. The wireless communication device according to claim 41,

wherein the information related to data units is the time length required for transmitting one or more data units for which transmission is tried.

46. The wireless communication device according to claim 41,

wherein the information related to data units is information on the number of data units for which transmission is tried.

47. The wireless communication device according to claim 41,

wherein, when said CTS transmitting means determines medium reservation time information after the reception of RTS, the transmitting means takes into account the time at which the communication device itself completes data reception.

48. The wireless communication device according to claim 41,

wherein said RTS transmitting means describes in RTS information on the period until the time until which the communication device itself can transmit, and

wherein said CTS transmitting means gives consideration so that said information on the period described in the RTS is not exceeded when it determines medium reservation time information after the reception of RTS.

49. The wireless communication device according to claim 41,

wherein said data transmitting means assigns sequence numbers to transmit data units,

wherein said RTS transmitting means describes in RTS the first sequence number of data for which transmission is tried, and notifies of information related to data units for which transmission is tried, and

wherein said CTS transmitting means refers to the first sequence number of data units described in the RTS, extracts data units already received from data units for which transmission is tried, excludes them from objects to be received, and then determines medium reservation time information.

50. The wireless communication device according to claim 49,

wherein, if selective acknowledgement is applied, said RTS transmitting means describes in RTS reception acknowledgement information containing the first sequence number of data units for which data transmission is tried and bit map information obtained by mapping the reception confirmation information on the subsequent data units into bits corresponding to the relative positions to the first sequence number, and further generates information related to said data units with only data units for which reception confirmation has not been obtained taken as objects to be transmitted, and

wherein, if selective acknowledgement is applied, said CTS transmitting means refers to said bit map information described in the RTS, extracts data units already received from data units for which transmission is tried, excludes them from the objects to be received, and then determines medium reservation time information.

51. The wireless communication device according to claim 41,

wherein, if a data unit already received is included in the data units to be transmitted described in the RTS, said CTS transmitting means describes ACK information in CTS.

52. The wireless communication device according to claim 41,

wherein said data transmitting means excludes the data units already received by the RTS receiving communication station from the objects to be transmitted based on the ACK information added to the CTS, and carries out data transmission based on the data rate described in the CTS.

53. The wireless communication device according to claim 49,

wherein said CTS transmitting means stores one or more pieces of data length information of data units to be received, of data for which transmission is tried as the outcome of the RTS, and describes in CTS the sequence number of the last data unit stored.

54. The wireless communication device according to claim 53,

wherein said RTS transmitting means stores the sequence number of said last data unit described in the CTS, and generates information related to data units for which transmission is tried in such form that the data unit indicated by the sequence number of said last data unit is not included in objects to be transmitted when an RTS is transmitted next time.

55. A wireless communication device for transmitting and receiving a plurality of data units in which sequence numbers are assigned to transmit data units to identify the data units, comprising:

an ACK information transmitting means which, if selective acknowledgement is applied, describes in a reception acknowledgement information ACK the sequence numbers of completely received data units in the order of sequence number, and bit map information represented by mapping the state of reception of data of the subsequent sequence numbers into relative bit positions from the sequence numbers in response to data reception, and transmits the information, and

a packet transmitting means which, if selective acknowledgement is applied, adds information indicating a causal data flow when it transmits transmit data and an acknowledgement in response to data reception/transmission.

56. The wireless communication device according to claim 55,

wherein, if said ACK information transmitting means does not support selective acknowledgement, it transmits said bit map information with zero set for all the bits of the bit map field.

57. The wireless communication device according to claim 55,

wherein, with respect to at least one data flow, the ARQ system in which sequence numbers are not assigned is adopted, and, when Link session is established, data is transmitted and received through the data flow, and thereby the communication device synchronizes its sequence numbers with those of the station on the other end.

58. A wireless communication device which makes random access concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the wireless communication device comprising:

an information generating means which generates information of request to send RTS, confirmative advice CTS, data, and acknowledgement ACK; and

a packet transfer communication means which transmits and receives packets in which any two or more of request to send RTS, confirmative advice CTS, data, and acknowledgement ACK are multiplexed.

59. The wireless communication device according to claim 58, further comprising:

a means which sets the time by which the other station'"'"'s transmission of a packet as the outcome of the transmission of a packet is completed, and describes the set time information as the reservation time information of the transmit packet.

60. The wireless communication device according to claim 58, further comprising:

a means which, in response to the reception of a packet containing RTS information, transmits a packet containing CTS information in accordance with the contents of the RTS; and

a means which, in response to the reception of a packet containing CTS information, transmits a packet containing data in accordance with the contents of the CTS.

61. The wireless communication device according to claim 58,

wherein, when generating RTS information, said information generating means describes first information which indicates whether RTS information may be added to CTS transmitted as the outcome of the RTS.

62. The wireless communication device according to claim 61,

wherein, when transmitting a return packet, said packet transmitting means judges whether RTS information may be added to CTS based on the first information in the causal RTS, and, if data it desires to transmit to the RTS transmitting communication station is present, transmits a CTS to which RTS information is added for the purpose of transmitting the data or a packet containing RTS information for the purpose of transmitting the data.

63. The wireless communication device according to claim 62,

wherein said packet transmitting means, when transmitting a return packet in response to the packet containing RTS information, if data of desiring to transmit to the RTS transmitting communication station is present, transmits a CTS to which RTS information is added for the purpose of transmitting the data or a packet containing RTS information for the purpose of transmitting the data.

64. The wireless communication device according to claim 61,

wherein said information generating means determines first information based on information elements contained in the packets received from the station as the destination of the RTS in the past.

65. The wireless communication device according to claim 58,

wherein, if said packet transfer communication means recognizes from the information in the RTS that the causal RTS transmitting communication station is trying to transmit data already received by the communication device itself when transmitting a CTS, the packet transfer communication means adds ACK information to the CTS.

66. The wireless communication device according to claim 58,

wherein, if said packet transfer communication means receives data which requests an ACK from the data transmitting communication station in response to the reception of a data packet and judges that it has not transmitted the ACK of the data, the packet transfer communication means adds ACK information when it transmits a packet of some kind to the data transmitting communication station.

67. The wireless communication device according to claim 66,

wherein said packet transfer communication means does not add ACK information to a packet in which RTS information is solely transmitted.

68. The wireless communication device according to claim 66,

wherein said packet transfer communication means transmits data which requests an ACK in a packet directed to two or more communication stations.

69. The wireless communication device according to claim 58,

wherein, when transmitting an RTS, said packet transfer communication means multiplexes an ACK request for requesting a return of the ACK of data it has transmitted so far.

70. The wireless communication device according to claim 58,

wherein, if said packet transfer communication means failed to receive the ACK of data it has transmitted so far, it multiplexes an ACK request for requesting a return of the ACK of data it has transmitted so far when transmitting an RTS.

71. The wireless communication device according to claim 69 or 70,

wherein, in response to the reception of an RTS with an ACK request multiplexed, said information generating means generates an ACK which indicates whether the reception of data transmitted from the RTS transmitting communication station has been completed or not, and

wherein said packet transfer communication means returns an ACK which indicates whether the reception of data transmitted from the RTS transmitting communication station has been completed or not, or, if it has failed to receive data transmitted from said RTS transmitting communication station, multiplexes a CTS which requests to retransmit the data and an ACK of the ACK request and returns them.

72. A wireless communication method for making random access concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the method comprising:

a communication quality measuring step in which the quality of receive signal is measured when an RTS is received;

a data rate determining step in which a data rate is determined based on the measured quality of receive signal;

a CTS transmitting step in which the data rate is described in an CTS as the outcome of the received RTS and transmitted; and

a data transmitting step in which, when CTS information is received, data transmission as the outcome of the CTS information is carried out based on the data rate described in the CTS.

73. A wireless communication method for transmitting and receiving a plurality of data units, comprising the steps of:

assigning sequence numbers to transmit data units to identify the data units, and, if selective acknowledgement is applied, describing in reception acknowledgement information ACK the sequence numbers of completely received data units in the order of sequence number and bit map information represented by mapping the state of reception of data of the subsequent sequence numbers into relative bit positions from the sequence numbers in response to data reception, and transmitting the information; and

adding information indicating a causal data flow when transmitting transmit data and an acknowledgement in response to data transmission/reception.

74. A wireless communication method for making random access concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the method comprising:

an information generating step in which information of request to send RTS, confirmative advice CTS, data, and acknowledgement ACK is generated; and

a packet transfer communication step in which a packet in which any two or more pieces of information of request to send RTS, confirmative advice CTS, data, and acknowledgement ACK are multiplexed is transmitted and received.

75. A computer program described in a computer-readable format for carrying out on a computer system the processing for controlling communicating operation in a communication environment in which random access is made concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the computer program comprising:

a communication quality measuring step in which the quality of receive signal is measured when an RTS is received;

a data rate determining step in which a data rate is determined based on the measured quality of receive signal;

a CTS transmitting step in which the data rate is described in a CTS as the outcome of the received RTS and transmitted; and

a data transmitting step in which, when CTS information is received, data transmission as the outcome of the CTS information is carried out based on the data rate described in the CTS.

76. A computer program described in a computer-readable format for carrying out on a computer system the control of communicating operation for transmitting and receiving a plurality of data units, the computer program comprising the steps of:

assigning sequence numbers to transmit data units to identify the data units, and, if selective acknowledgement is applied, describing in reception acknowledgement information ACK the sequence numbers of completely received data units in the order of sequence number and bit map information represented by mapping the state of reception of data of the subsequent sequence numbers into relative bit positions from the sequence numbers in response to data reception, and transmitting the information; and

adding information indicating a causal data flow when transmitting transmit data and an acknowledgement in response to data transmission/reception.

77. A computer program described in a computer-readable format for carrying out on a computer system the processing for controlling communicating operation in a communication environment in which random access is made concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the computer program comprising:

an information generating step in which information of request to send RTS, confirmative advice CTS, data, and acknowledgement ACK is generated; and

a packet transfer communication step in which a packet in which any two or more pieces of information of request to send RTS, confirmative advice CTS, data, and acknowledgement ACK are multiplexed is transmitted and received.

78. A wireless communication system in which random access is made concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission,

wherein the RTS transmitting communication station transmits an RTS in which information related to one or more data units for which transmission is tried is described.

79. The wireless communication system according to claim 78,

wherein the information related to data units is the data length of each data unit for which transmission is tried.

80. The wireless communication system according to claim 78,

wherein the information related to data units is the sum of the data lengths of one or more data units for which transmission is tried.

81. The wireless communication system according to claim 78,

wherein the information related to data units is the time length required for transmitting one or more data units for which transmission is tried.

82. The wireless communication system according to claim 78,

wherein the information related to data units is information on the number of data units for which transmission is tried.

83. The wireless communication system according to claim 78,

wherein, when the RTS receiving communication station determines medium reservation time information after the reception of RTS, the station takes into account the time at which the station itself completes data reception.

84. The wireless communication system according to claim 78,

wherein the RTS transmitting communication station describes in RTS information on the period until the time until which the communication station itself can transmit, and

wherein the RTS receiving communication station gives consideration so that said information on the period described in the RTS is not exceeded when it determines medium reservation time information after the reception of RTS.

85. The wireless communication system according to claim 78,

wherein the RTS transmitting communication station describes in RTS the time that lapses before the reception of a packet containing CTS information, transmitted as the outcome of the reception of RTS information, as medium reservation time information, and

wherein other communication stations which receive RTS set a NAV, and keep it effective and communication stations themselves in transmission prohibited state over the duration of medium reservation time information.

86. The wireless communication system according to claim 78,

wherein the RTS receiving communication station measures the quality of receive signal and determines a data rate based on the result of measurement.

87. The wireless communication system according to claim 78,

wherein the CTS transmitting communication station describes in CTS a data rate at which it desires to receive, and transmits the CTS.

88. The wireless communication system according to claim 87,

wherein the CTS receiving communication station carries out data transmission as the outcome of the reception of CTS information based on the data rate described in the CTS.

89. The wireless communication system according to claim 78,

wherein the CTS transmitting communication station describes in CTS the time that lapses before the reception of a data packet, transmitted as the outcome of the reception of CTS information, as medium reservation time information, and

wherein other communication stations which receive CTS set a NAV, and keep it effective and themselves in transmission prohibited state over the duration of medium reservation time information.

90. The wireless communication system according to claim 89,

wherein the CTS transmitting communication station determines medium reservation time information which corresponds to the time period during which the reception of a data unit, transmitted from the RTS transmitting end, is completed based on the information related to each data unit described in the received RTS.

91. The wireless communication system according to claim 89,

wherein, if it is described in RTS that a plurality of data units are transmitted from the RTS transmitting communication station, the CTS transmitting communication station determines medium reservation time information which corresponds to the time period during which the reception of all the data units is completed.

92. The wireless communication system according to claim 89,

wherein the CTS receiving communication station carries out data transmission as the outcome of the reception of CTS information based on the data rate described in the CTS so that the transmission is completed within the time specified by the medium reservation time information.

93. The wireless communication system according to claim 78,

wherein the RTS transmitting communication station assigns sequence numbers to transmit data units, describes in RTS the first sequence number of data it tries to transmit, and notifies of information related to the data units it tries to transmit.

94. The wireless communication system according to claim 93,

wherein the RTS receiving communication station refers to the first sequence number of data units described in RTS, extracts data units already received from data units for which transmission is tried, excludes them from objects to be received, and then determines medium reservation time information.

95. The wireless communication system according to claim 93,

wherein, if selective acknowledgement is applied, the RTS transmitting communication station describes in RTS reception acknowledgement information containing the first sequence number of data units for which data transmission is tried and bit map information obtained by mapping the reception confirmation information on the subsequent data units into bits corresponding to the relative positions to the first sequence number, and further generates information related to said data units with only data units for which reception confirmation has not been obtained taken as objects to be transmitted, and

wherein, if selective acknowledgement is applied, the RTS receiving communication station refers to said bit map information described in the RTS, extracts data units it has already received from data units for which transmission is tried, and then determines medium reservation time information.

96. The wireless communication system according to claim 93,

wherein the RTS receiving communication station stores one or more pieces of data length information of data units to be received, of data for which transmission is tried as the outcome of the RTS, and describes in CTS the sequence number of the last data unit stored.

97. The wireless communication system according to claim 96,

wherein the CTS receiving communication station stores the sequence number of said last data unit described in the CTS, and generates information related to data units for which transmission is tried in such form that the data unit indicated by the sequence number of said last data unit is not included in objects to be transmitted when an RTS is transmitted next time.

98. The wireless communication system according to claim 78,

wherein, if a data unit already received is included in the data units to be transmitted described in the RTS, the RTS receiving communication station describes ACK information in CTS.

99. The wireless communication system according to claim 78,

wherein the CTS receiving communication station excludes the data units already received by the RTS receiving communication station from the objects to be transmitted based on the ACK information added to the CTS, and carries out data transmission based on the data rate described in the CTS.

100. A wireless communication device which makes random access concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the wireless communication device comprising:

an RTS transmitting means which transmits an RTS when data transmission is requested;

a data transmitting means which, when CTS information is received, carries out data transmission as the outcome of the CTS information; and

a CTS transmitting means which, when an RTS is received, transmits a CTS as the outcome of the RTS,

wherein said RTS transmitting means transmits an RTS in which information related to one or more data units for which transmission is tried is described.

101. The wireless communication device according to claim 100,

wherein the information related to data units is the data length of each data unit for which transmission is tried.

102. The wireless communication device according to claim 100,

wherein the information related to data units is the sum of the data lengths of one or more data units for which transmission is tried.

103. The wireless communication device according to claim 100,

wherein the information related to data units is the time length required for transmitting one or more data units for which transmission is tried.

104. The wireless communication device according to claim 100,

wherein the information related to data units is information on the number of data units for which transmission is tried.

105. The wireless communication device according to claim 100,

wherein said CTS transmitting means describes in CTS medium reservation time information which is determined after the reception of RTS with consideration given to the time at which the communication device itself completes data reception.

106. The wireless communication device according to claim 100,

wherein said RTS transmitting means describes in RTS information on the period until the time until which the communication device itself can transmit, and

wherein said CTS transmitting means describes in CTS medium reservation time information determined with consideration given so that said information on the period described in the received RTS is not exceeded.

107. The wireless communication device according to claim 100,

wherein said RTS transmitting means describes in RTS the time that lapses before the reception of a packet containing CTS information, transmitted as the outcome of the reception of RTS information, as medium reservation time information.

108. The wireless communication device according to claim 100, further comprising:

a communication quality measuring means which measures the quality of receive signal when an RTS is received; and

a data rate determining means which determines a data rate based on the measured quality of receive signal.

109. The wireless communication device according to claim 100,

wherein said CTS transmitting means describes in CTS a data rate at which it desires to receive, and transmits the CTS.

110. The wireless communication device according to claim 109,

wherein said data transmitting means carries out data transmission as the outcome of the reception of CTS information based on the data rate described in the CTS.

111. The wireless communication device according to claim 100,

wherein said CTS transmitting means describes in CTS the time that lapses before the reception of a data packet, transmitted as the outcome of the reception of CTS information, as medium reservation time information.

112. The wireless communication device according to claim 111,

wherein said CTS transmitting means determines medium reservation time information which corresponds to the time period during which the reception of a data unit, transmitted from the RTS transmitting end, is completed based on the information related to each data unit described in the received RTS.

113. The wireless communication device according to claim 111,

wherein, if an RTS in which it is described that a plurality of data units are transmitted is received, said CTS transmitting means determines medium reservation time information which corresponds to the time period during which the reception of all the data units is completed.

114. The wireless communication device according to claim 111,

wherein said data transmitting means carries out data transmission as the outcome of the reception of CTS information based on the data rate described in the received CTS so that the transmission is completed within the time specified by the medium reservation time information.

115. The wireless communication device according to claim 100,

wherein said RTS transmitting means assigns sequence numbers to transmit data units, describes in RTS the first sequence number of data it tries to transmit, and notifies of information related to the data units it tries to transmit.

116. The wireless communication device according to claim 115,

wherein said CTS transmitting means describes in CTS medium reservation time information determined after referring to the first sequence number of data units described in RTS, extracting data units already received from data units for which transmission is tried, and excluding them from objects to be received.

117. The wireless communication device according to claim 115,

wherein, if selective acknowledgement is applied, said RTS transmitting means describes in RTS reception acknowledgement information containing the first sequence number of data units for which data transmission is tried and bit map information obtained by mapping the reception confirmation information on the subsequent data units into bits corresponding to the relative positions to the first sequence number, and further generates information related to said data units with only data units for which reception confirmation has not been obtained taken as objects to be transmitted, and

wherein, if selective acknowledgement is applied, said CTS transmitting means describes in CTS medium reservation time information determined after referring to said bit map information described in the received RTS, and extracting data units it has already received from data units for which transmission is tried.

118. The wireless communication device according to claim 115,

wherein said CTS transmitting means stores one or more pieces of data length information of data units to be received, of data for which transmission is tried as the outcome of the received RTS, and describes in CTS the sequence number of the last data unit stored.

119. The wireless communication device according to claim 118,

wherein said data transmitting means stores the sequence number of said last data unit described in CTS, and generates information related to data units for which transmission is tried in such form that the data unit indicated by the sequence number of said last data unit is not included in objects to be transmitted when an RTS is transmitted next time.

120. The wireless communication device according to claim 100,

wherein, if a data unit already received is included in the data units to be transmitted described in the RTS, said CTS transmitting means describes ACK information in CTS.

121. The wireless communication device according to claim 100,

wherein said data transmitting means excludes the data units already received by the RTS receiving communication station from the objects to be transmitted based on the ACK information added to the CTS, and carries out data transmission based on the data rate described in the CTS.

122. A wireless communication method for making random access concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the method comprising:

an RTS transmitting step in which, when data transmission is requested, an RTS in which information related to one or more data units for which transmission is tried is described is transmitted;

a CTS transmitting step in which, when an RTS is received, a CTS in which medium reservation time information determined based on the information related to each data unit described in the RTS and the data rate is transmitted; and

a data transmitting step in which, when CTS information is received, data transmission as the outcome of the reception of the CTS information is carried out so that the transmission is completed within the time specified by the medium reservation time information.

123. A computer program described in a computer-readable format for carrying out on a computer system the processing for controlling communicating operation in a communication environment in which random access is made concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, the computer program comprising:

an RTS transmitting step in which, when data transmission is requested, an RTS in which information related to one or more data units for which transmission is tried is described is transmitted;

a CTS transmitting step in which, when an RTS is received, a CTS in which medium reservation time information determined based on the information related to each data unit described in the RTS and the data rate is described is transmitted; and

a data transmitting step in which, when CTS information is received, data transmission as the outcome of the reception of CTS information is carried out so that the transmission is completed within the time specified by the medium reservation time information.

124. A wireless communication system in which a data transmitting communication station acquires transmission right on a medium and then carries out data communication with a data receiving communication station,

wherein, after data transmission from the data transmitting communication station is stopped, it is detected whether the subsequent data is present in the data transmitting communication station or not, and, if the subsequent data is present, it is made easier for the data transmitting communication station to acquire transmission right for transmitting the subsequent data.

125. The wireless communication system according to claim 124, in which medium access control wherein each communication station confirms that said medium is clear only for a predetermined time, waits for an arbitrary backoff time, and then acquires transmission right is carried out by each communication station, wherein, when the data receiving communication station detects the presence of the subsequent data in the data transmitting communication station, the data receiving communication station tries to acquire transmission right on said medium, and transmits a signal onto said medium for eliminating other communication stations'"'"' transmission right and thereby makes it easier for the data transmitting communication station to acquire transmission right for transmitting the subsequent data.

126. The wireless communication system according to claim 124, in which medium access control is carried out by each communication station concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission,

wherein, when the data receiving communication station detects the presence of the subsequent data in the data transmitting communication station, the data receiving communication station transmits a dummy RTS or an RTS onto said medium for eliminating other communication stations'"'"' transmission right, and there by makes it easier for the data transmitting communication station to transmit an RTS for transmitting the subsequent data.

127. The wireless communication system according to claim 124,

wherein the presence or absence of the subsequent data in the data transmitting communication station is detected based on the history of communication between the data transmitting communication station and the data receiving communication station in the past.

128. The wireless communication system according to claim 124,

wherein the presence or absence of the subsequent data in the data transmitting communication station is detected based on that an RTS from the data transmitting communication station reaches the data receiving communication station and the data receiving communication station can not return a CTS, or that after the data receiving communication station returns a CTS,

transmit data does not reach the data receiving communication station.

129. The wireless communication system according to claim 124,

wherein the presence or absence of the subsequent data in the data transmitting communication station is detected based on specific information elements indicating the presence or absence of the subsequent data, contained in the data transmitted from the data transmitting communication station.

130. A wireless communication device which operates in a communication environment in which each communication station acquires transmission right on the medium before carrying out data communication, comprising:

a communicating means which transmits and receives data on said medium;

a data processing means which processes transmit/receive data; and

a medium access controlling means which controls access operation on said medium,

wherein, after data transmission from the data transmitting communication station is stopped, said data processing means detects the presence or absence of the subsequent data in the data transmitting communication station, and

wherein, if the subsequent data is present, said medium access controlling means makes it easier for the data transmitting communication station to acquire transmission right for transmitting the subsequent data.

131. The wireless communication device according to claim 130,

wherein said medium access controlling means carries out medium access control wherein it confirms that said medium only for a predetermined time, waits for an arbitrary backoff time, and then acquires transmission right, and, if it detects the presence of the subsequent data in the data transmitting communication station, tries to acquire transmission right on said medium, transmits a signal to said medium for eliminating other communication stations'"'"' transmission right, and thereby makes it easier for the data transmitting communication station to acquire transmission right for transmitting the subsequent data.

132. The wireless communication device according to claim 130,

wherein said medium access controlling means carries out medium access control concomitantly using the RTS/CTS method wherein a communication station as the origin of data transmission transmits a request to send packet RTS and starts data transmission in response to the reception of a response packet CTS from a communication station as the destination of data transmission, and, if it detects the presence of the subsequent data in the data transmitting communication station, transmits a dummy RTS or an RTS onto said medium for eliminating other communication stations'"'"' transmission right, and thereby makes it easier for the data transmitting communication station to acquire transmission right for transmitting the subsequent data.

133. The wireless communication device according to claim 130,

wherein said data processing means detects the presence or absence of the subsequent data in the data transmitting communication station based on the history of communication with the data transmitting communication station in the past.

134. The wireless communication device according to claim 130,

wherein said data processing means detects the presence or absence of the subsequent data in the data transmitting communication station based on that it can not return a CTS in response to an RTS from the data transmitting communication station, or that it returns a CTS in response to an RTS from the data transmitting communication station thereafter the transmission of transmit data from the data transmitting communication station is stopped.

135. The wireless communication device according to claim 130,

wherein said data processing means detects the presence or absence of the subsequent data in the data transmitting communication station based on specific information elements indicating the presence or absence of the subsequent data, contained in the data transmitted from the data transmitting communication station.

136. A wireless communication method in a communication environment in which each communication station acquires transmission right on the medium before carrying out data communication, comprising:

a step in which the presence or absence of transmit data from other communication stations is detected; and

a medium access control step in which, in response to detection of the presence of transmit data from another communication station, a signal is transmitted onto said medium for eliminating other communication stations'"'"' transmission right so as to make it easier for the communication station to acquire transmission right for transmitting data.

137. A computer program described in a computer-readable format for carrying out on a computer system the processing for controlling communicating operation in a communication environment in which each communication station acquires transmission right on the medium before carrying out data communication, the computer program comprising:

a step in which the presence or absence of transmit data from other communication stations is detected; and

a medium access control step in which, in response to detection of the presence of transmit data from another communication station, a signal is transmitted onto said medium for eliminating other communication stations'"'"' transmission right so as to make it easier for the communication station to acquire transmission right for transmitting data.