Communication apparatus and communication method

• US 20060034174A1
• Filed: 08/10/2005
• Published: 02/16/2006
• Est. Priority Date: 08/11/2004
• Status: Active Grant

• Current Assignee: Palmira Wireless AG
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Tandai, Tomoya, Takagi, Masahiro, Adachi, Tomoko, Utsunomiya, Yoriko, Nishibayashi, Yasuyuki, Nakajima, Tetsu
• Granted Patent: US 7,738,441 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/1621 Group acknowledgement, i.e. the acknowledgement message defining a range of identifiers, e.g. of sequence numbers
• CPC Class Codes: H04L 1/1642 Formats specially adapted for sequence numbers
• CPC Class Codes: H04L 1/1829 Arrangements specially adapted for the receiver end

Abstract

A communication apparatus includes a receiving device configured to receive one physical frame in which a plurality of MAC frames are aggregated. This physical frame includes one acknowledgement request frame for the plurality of MAC frames. The apparatus includes an acknowledgement frame forming device configured to form an acknowledgement frame representing reception statuses of the plurality of MAC frames in response to the acknowledgement request frame. The apparatus also includes a transmitting device configured to transmit the acknowledgement frame. This acknowledgement frame includes a compressed acknowledgement frame representing an acknowledgement bitmap having a size equal to a maximum number of MSDUs (MAC Service Data Units) when one MPDU (MAC Protocol Data Unit) corresponds to one MSDU.

Claims

1. A communication apparatus comprising:

a receiving device configured to receive one physical frame in which a plurality of MAC frames are aggregated, said physical frame including one acknowledgement request frame for said plurality of MAC frames;

an acknowledgement frame forming device configured to form an acknowledgement frame representing reception statuses of said plurality of MAC frames, in response to the acknowledgement request frame; and

a transmitting device configured to transmit the acknowledgement frame, wherein the acknowledgement frame is a compressed acknowledgement frame representing an acknowledgement bitmap having a size equal to a maximum number of MSDUs (MAC Service Data Units) when one MPDU (MAC Protocol Data Unit) corresponds to one MSDU.

2. An apparatus according to claim 1, which further comprises:

a storage device configured to store an acknowledgement bitmap of the acknowledgement frame transmitted by the transmitting device; and

a device configured to receive a retransmitted acknowledgement request frame, and

in which the acknowledgement frame forming device forms an acknowledgement frame representing reception statuses based on the acknowledgement bitmap stored in the storage device, in response to the retransmitted acknowledgement request frame.

3. An apparatus according to claim 2, wherein on the basis of comparison of a value of acknowledgement start point sequence control in the retransmitted acknowledgement request frame with a value of a sequence number of a last received MAC frame, and in response to the acknowledgement request frame, the acknowledgement frame forming device sets a sequence number of a first successfully received MAC frame as the value of acknowledgement start point sequence control, and forms an acknowledgement frame having the sequence number of the first MAC frame as a start point.

4. An apparatus according to claim 2, wherein if a value of acknowledgement start point sequence control in the retransmitted acknowledgement request frame is larger than a value of a sequence number of a last received MAC frame, the acknowledgement frame forming device forms, in response to the acknowledgement request frame, an acknowledgement frame containing an acknowledgement bitmap indicating that no MAC frame is successfully received.

5. A communication apparatus comprising:

a physical frame forming device configured to form one physical frame in which a plurality of MAC frames are aggregated;

a transmitting device configured to transmit the physical frame; and

a receiving device configured to receive an acknowledgement frame which responds as an implicit acknowledgement request to completion of the physical frame.

6. An apparatus according to claim 5, further comprising an acknowledgement request transmitting device configured to, if the acknowledgement frame cannot be received even when a predetermined time has elapsed after the physical frame is transmitted, set a sequence number of a first MAC frame in the physical frame as a value of acknowledgement start point sequence control, and transmit an explicit acknowledgement request frame.

7. An apparatus according to claim 6, further comprising a retransmitting device configured to retransmit all said plurality of MAC frames in response to the explicit acknowledgement request frame, if an acknowledgement bitmap contained in the acknowledgement frame received by the receiving device indicates that no MAC frame is successfully received.

8. An apparatus according to claim 5, further comprising a retransmitting device configured to retransmit an unacknowledged MAC frame having a sequence number less than a value of acknowledgement start point sequence control in the acknowledgement frame received by the receiving device.

9. An apparatus according to claim 5, further comprising:

a subqueue for MAC frame retransmission;

a sequence number storage device configured to store sequence number information of a MAC frame aggregated in the physical frame transmitted by the transmitting device;

a device configured to determine a MAC frame to be retransmitted, on the basis of an acknowledgement bitmap in the acknowledgement frame received by the receiving device, and the sequence number stored in the sequence number storage device; and

a device configured to delete continuously successfully transmitted MAC frames from a head of the subqueue for MAC frame retransmission, and add a MAC frame to be transmitted next to the subqueue for MAC frame retransmission.

10. A communication apparatus comprising:

a receiving device configured to receive one physical frame in which a plurality of MAC frames are aggregated;

a forming device configured to form an acknowledgement frame which responds as an implicit acknowledgement request to completion of the physical frame received by the receiving device, and contains reception statuses of said plurality of MAC frames in the physical frame as an acknowledgement bitmap, and in which a sequence number of a first successfully received MAC frame in the physical frame is set as an acknowledgement start point sequence number; and

a transmitting device configured to transmit the acknowledgement frame.

11. An apparatus according to claim 10, wherein the acknowledgement frame is a compressed acknowledgement representing an acknowledgement bitmap having a size equal to a maximum number of MSDUs (MAC Service Data Units) when one MPDU (MAC Protocol Data Unit) corresponds to one MSDU.

12. An apparatus according to claim 10, which further comprises:

a storage device configured to store the acknowledgement bitmap of the acknowledgement frame transmitted by the transmitting device; and

a device configured to receive an explicit acknowledgement request frame, and

in which the acknowledgement frame forming device transmits an acknowledgement frame representing reception statuses based on the acknowledgement bitmap stored in the storage device, in response to the explicit acknowledgement request frame.

13. An apparatus according to claim 12, wherein if a value of acknowledgement start point sequence control in the explicit acknowledgement request frame is larger than a value of a sequence number of a last received MAC frame, the acknowledgement frame forming device forms an acknowledgement frame containing an acknowledgement bitmap which indicates that no MAC frame is successfully received, in response to the acknowledgement request frame.

14. An apparatus according to claim 12, wherein on the basis of comparison of a value of acknowledgement start point sequence control in the retransmitted acknowledgement request frame with a value of a sequence number of a last received MAC frame, and in response to the acknowledgement request frame, the acknowledgement frame forming device sets a sequence number of a first successfully received MAC frame as the value of acknowledgement start point sequence control, and transmits an acknowledgement frame having the sequence number of the first MAC frame as a start point.

15. A communication method comprising:

receiving one physical frame in which a plurality of MAC frames are aggregated, said physical frame including acknowledgement request frame for said plurality of MAC frames;

forming an acknowledgement frame representing reception statuses of said plurality of MAC frames, in response to the acknowledgement request frame; and

transmitting the acknowledgement frame, wherein the acknowledgement frame is a compressed acknowledgement frame representing an acknowledgement bitmap having a size equal to a maximum number of MSDUs (MAC Service Data Units) when one MPDU (MAC Protocol Data Unit) corresponds to one MSDU.

16. A communication method comprising:

forming one physical frame in which a plurality of MAC frames are aggregated;

transmitting the physical frame; and

receiving an acknowledgement frame which responds as an implicit acknowledgement request to completion of the physical frame.

17. A communication method comprising:

receiving one physical frame in which a plurality of MAC frames are aggregated;

forming an acknowledgement frame which responds as an implicit acknowledgement request to completion of the received physical frame, and contains reception statuses of the plurality of MAC frames in the physical frame as an acknowledgement bitmap, and in which a sequence number of a first successfully received MAC frame in the physical frame is set as an acknowledgement start point sequence number; and

transmitting the acknowledgement frame.