Method and device for retransmission of transmitted units

• US 20050008035A1
• Filed: 11/12/2001
• Published: 01/13/2005
• Est. Priority Date: 11/12/2001
• Status: Abandoned Application

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Salokannel, Juha, Eklund, Carl
• Application Number:
  US10/494,582
• Publication Number:
  US 20050008035A1
• Time in Patent Office: Days
• US Class Current: 370/473
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/1642 Formats specially adapted for sequence numbers
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols

Abstract

The invention relates to a method for retransmitting a transmission unit (12) via an air interface in a wireless access system employing fragmentation for transmissions, wherein the available transmission capacity on said air interface is variable, and wherein said transmission unit (12) was transmitted a first time together with fragmentation information. In order to enable such a retransmission, it is proposed that the transmission unit (12) is retransmitted after a refragmentation with information FC, FSN on this refragmentation and with at least some of the fragmentation information FC′, FSN′, TSN that was transmitted before with said transmission unit (12) in the first transmission. The invention equally relates to a corresponding wireless access system and to a corresponding transmitting unit for such a wireless access system.

Claims

1. Method for retransmitting a transmission unit (12) via an air interface in a wireless access system employing fragmentation for transmissions, wherein the available transmission capacity on said air interface is variable, wherein said transmission unit (12) was transmitted a first time together with fragmentation information (TSN,FC′

,FSN′

), and wherein said transmission unit (12) is retransmitted after a refragmentation with information (FC,FSN) on said refragmentation and with at least some of said fragmentation information (TSN,FC′

,FSN′

) that was transmitted before with said transmission unit (12) in said first transmission.

2. Method according to claim 1, wherein said fragmentation information on a fragmentation for a first transmission comprises at least one of a fragmentation control (FC′

), a fragmentation sequence number (FSN′

) and a transmission unit sequence number (TSN).

3. Method according to claim 1, wherein said refragmentation information comprises at least one of a fragmentation control (FC) and a fragmentation sequence number (FSN).

4. Method according to claim 1, wherein each fragment (21,22-24) of a refragmented transmission unit (12) is provided with a subheader comprising for the fragmentation and refragmentation information:

a field for a fragmentation sequence number (FSN′

) assigned to said transmission unit (12) in the first transmission;

a field for a fragmentation sequence number (FSN) assigned to said fragment (21,22-24) of said transmission unit (12) for the retransmission;

a field for a fragmentation control (FC′

) assigned to said transmission unit (12) in the first transmission;

a field for a fragmentation control (FC) assigned to said fragment (21,22-24) of said transmission unit (12) for the retransmission; and

a field for a transmission unit sequence number (TSN) assigned to said transmission unit (12) in the first transmission.

5. Method according to claim 4, wherein said fields for a fragmentation sequence number (FSN,FSN′

) are fields of 5 bits, wherein said fields for a fragmentation control (FC,FC′

) are fields of 2 bits, and wherein said field for a transmission unit sequence number (TSN) is a field of 7 bits.

6. Method according to claim 1, wherein each transmission unit (12) transmitted a first time and each fragment (21,22-24) of a transmission unit (12) refragmented for retransmission is provided with a subheader comprising the same dedicated fields (TSN,FC,FC′

,FSN,FSN′

) for fragmentation information.

7. Method according to claim 1, wherein said transmission unit (12) is one of:

a MAC (medium access control) SDU (service data unit) transmitted in a MAC PDU (protocol data unit) without packing;

a MAC SDU fragment transmitted in a MAC PDU without packing;

a MAC SDU transmitted in a MAC PDU with packing; and

a MAC SDU fragment transmitted in a MAC PDU with packing.

8. Method according to claim 1, wherein said transmission unit (12) is retransmitted upon a request by a receiving unit of said wireless access system to which said transmission unit (12) was to be transmitted.

9. Transmitting unit for a wireless access system comprising means for transmitting transmission units (11-15) and for retransmitting transmission units (12) according to claim 1.

10. Transmitting unit according to claim 9, wherein said transmitting unit is part of a first transceiver device, and wherein said transmitting unit is transmitting transmission units (11-15) to a receiving unit which is part of a second transceiver device.

11. Transmitting unit according to claim 9, comprising:

means for fragmenting each data unit (MAC SDU#1, MAC SDU#2) that is to be transmitted via an air interface into at least one transmission unit (11-15) and for providing each transmission unit (11-15) with corresponding fragmentation information (TSN,FC′

,FSN′

);

means for transmitting transmission units (11-15) to a receiving unit via said air interface;

means for receiving a retransmission request by a receiving unit requesting that a transmission unit (12) is to be retransmitted; and

means for refragmenting a transmission unit (12) for which a retransmission was requested by a receiving unit, and for providing said transmission unit (12) for retransmission with information (FC,FSN) on said refragmentation and with at least some of said fragmentation information (TSN,FC′

,FSN′

) provided to said transmission unit (12) for a first transmission.

12. Wireless access system comprising a transmitting unit according to claim 9 and a receiving unit comprising means for receiving transmission units transmitted by said transmitting unit and means for requesting a retransmission of transmission units (12) if required.