METHOD AND APPARATUS FOR LAYER 2 ARQ FOR PACKETS

• US 20080279171A1
• Filed: 05/09/2008
• Published: 11/13/2008
• Est. Priority Date: 05/09/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Van Lieshout, Gert Jan, Van Der Velde, Himke, KIM, Seong-Hun
• Granted Patent: US 8,351,380 B2
• Time in Patent Office: Days
• US Class Current: 370/346
• CPC Class Codes: H04L 1/1685 the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/1858 Transmission or retransmission of more than one copy of acknowledgement message
• CPC Class Codes: H04L 1/1883 using multiple timers
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 80/02 Data link layer protocols
• CPC Class Codes: H04W 80/06 Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16

Abstract

An Automatic Repeat reQuest (ARQ) method in a communication system having a protocol layer structure, in which a Layer 2 (L2) transmitter for generating an upper layer packet in a size suitable for transmission over a radio channel and transmitting the upper layer packet to a lower layer, transmits, to a receiver, polling information representative of an indicator for ordering the generation of a status report, and performs packet ARQ according to whether the status report is received within a predetermined time. The method includes determining whether there is a possibility that upper layer data contained in a packet data unit to be transmitted along with the polling information will cause an upper layer message in the opposite direction; and when there is a possibility that the upper layer data will cause an upper layer message, generating polling information ordering a receiver to wait for a predetermined time after receipt of a packet and to transmit an upper layer packet generated for the waiting time along with a status report, including the polling information in the packet data unit, and delivering the packet data unit to the lower layer.

Claims

1. A packet Automatic Repeat reQuest (ARQ) method in a communication system having a protocol layer structure, in which a Layer 2 (L2) transmitter for generating an upper layer packet in a size suitable for transmission over a radio channel and transmitting the upper layer packet to a lower layer, transmits, to a receiver, polling information representative of an indicator for ordering the generation of a status report, and performs packet ARQ according to whether the status report is received within a predetermined time, the method comprising:

determining if there is a possibility that upper layer data contained in a packet data unit to be transmitted along with the polling information will cause an upper layer message in an opposite direction; and

when there is a possibility that the upper layer data will cause an upper layer message, generating polling information ordering a receiver to wait for a predetermined time after receipt of a packet and to transmit an upper layer packet time along with a status report, including the polling information in the packet data unit, and delivering the packet data unit to the lower layer.

2. The packet ARQ method of claim 1, wherein the possibility is determined based on a type of a service connected to the L2 transmitter or a property of the upper layer packet.

3. The packet ARQ method of claim 1, wherein the polling is triggered when the last L2 packet data unit stored in a transmission buffer is transmitted.

4. The packet ARQ method of claim 1, further comprising:

monitoring whether a reception status report responsive to the polling information is received, during a predetermined time, and when the reception status report is received, transmitting a status report to the receiver in response thereto.

5. The packet ARQ method of claim 1, further comprising:

including polling information in the packet data unit, transmitting the packet data unit to the lower layer, and starting a polling timer; and

monitoring if a reception status report responsive to the polling information is received, and if no reception status report is received before the polling timer expires, retransmitting the packet data unit including the polling information, and staring the polling timer.

6. A packet Automatic Repeat reQuest (ARQ) method in a communication system having a protocol layer structure, in which a Layer 2 (L2) receiver for assembling lower layer data received over a radio channel and transmitting the lower layer data to an upper layer, receives polling information representative of an indicator for ordering the generation of a status report, and transmits the status report to a transmitter within a predetermined time, the method comprising:

upon receiving a packet data unit including polling information from the transmitter, starting a first timer and waiting for a predetermined time; and

transmitting an upper layer packet to the transmitter along with a reception status report responsive to the polling information.

7. The packet ARQ method of claim 6, wherein the polling information comprises indication information for generating an order to transmit a reception status report for the packet data unit along with an upper layer packet to be newly generated.

8. The packet ARQ method of claim 6, wherein when a responding scheme to the polling information is previously set in a call setup process so as to transmit a reception status report for a packet data unit along with an upper layer packet to be newly generated, the polling information is determined as polling information corresponding to a predetermined polling information-responding scheme.

9. The packet ARQ method of claim 6, further comprising:

transmitting an upper layer packet and a reception status report together to the transmitter, starting a second timer, and monitoring if polling information which caused a reception status report transmitted along with a coupled packet data unit is retransmitted; and

when no polling information is retransmitted before the second timer expires, deleting the coupled packet data unit.

10. A method for retransmitting a packet data unit in a communication system having a protocol layer structure, in which a Layer 2 (L2) transmitter for generating an upper layer packet in a size suitable for transmission over a radio channel and transmitting the upper layer packet to a lower layer, transmits, to a receiver, polling information representative of an indicator for ordering the generation of a status report, and performs packet Automatic Repeat reQuest (ARQ) according to whether the status report is received within a predetermined time, the method comprising:

when a predetermined polling triggering condition is satisfied, generating an L2 packet data unit containing polling information, and delivering the L2 packet data unit to the lower layer;

determining if the L2 packet data unit containing the polling information has been successfully transmitted in a Hybrid ARQ (HARQ) level;

when the L2 packet data unit containing the polling information has been successfully transmitted in the HARQ level, starting a polling timer and determining if a reception status report is received before the polling timer expires; and

when no reception status report is received before the polling timer expires, retransmitting only the polling information.

11. The method of claim 10, wherein the polling triggering condition is satisfied, when the last data stored in a transmission buffer or a retransmission buffer is transmitted, when a predetermined timer started after transmission of the polling information expires, or when an amount of an outstanding L2 packet data unit in an L2 packet data unit transmitted to the opposite L2 transmitter, stored in the retransmission buffer, exceeds a predetermined ratio of the total buffer size to the amount of the outstanding L2 packet data unit.

12. The method of claim 10, further comprising:

when the L2 packet data unit containing the polling information has not been successfully transmitted in the HARQ level, performing retransmission on the L2 packet data unit containing the polling information, and determining if the L2 packet data unit has been successfully transmitted in the HARQ level.

13. A packet Automatic Repeat reQuest (ARQ) method in a communication system having a protocol layer structure, in which a Layer 2 (L2) transmitter for generating an upper layer packet in a size suitable for transmission over a radio channel and transmitting the upper layer packet to a lower layer, transmits, to a receiver, polling information representative of an indicator for ordering the generation of a status report, and performs packet ARQ according to whether the status report is received within a predetermined time, the method comprising:

waiting until a predetermined time elapses, after successfully transmitting an L2 packet data unit containing polling information;

upon receiving an L2 packet data unit from an opposite L2 device after a lapse of the predetermined time, determining if a reception status report message is included in the received L2 packet data;

if no reception status report message is included, starting a polling timer and determining if a reception status report message is received; and

retransmitting the polling information if no reception status report message is received until the polling timer expires.

14. A packet Automatic Repeat reQuest (ARQ) method in a communication system having a protocol layer structure, in which a Layer 2 (L2) transmitter for generating an upper layer packet in a size suitable for transmission over a radio channel and transmitting the upper layer packet to a lower layer, transmits, to a receiver, polling information representative of an indicator for ordering the generation of a status report, and performs packet ARQ according to whether the status report is received within a predetermined time, the method comprising:

when there is a need to retransmit a polling packet data unit as no status report is received within the predetermined time, determining whether to perform resegmented retransmission according to whether a size of an L2 packet data unit transmittable over allocated transmission resources is less than a size of polling packet data unit to be retransmitted;

after determining to perform resegmented retransmission, resegmenting the last transmittable byte of a payload of the polling packet data unit to be retransmitted, to generate a resegmented packet data unit; and

transmitting the resegmented packet data unit.

15. A Layer 2 (L2) transmitter in a communication system having a protocol layer structure, for generating an upper layer packet in a size suitable for transmission over a radio channel, transmitting the upper layer packet to a lower layer, transmitting, to a receiver, polling information representative of an indicator for ordering the generation of a status report, and performing packet Automatic Repeat reQuest (ARQ) according to whether the status report is received within a predetermined time, the transmitter comprising:

a transmission buffer for storing data provided from an upper layer;

a transmission controller for scheduling transmission data and framing the data in a packet data unit with a proper size;

a framing unit for resegmenting the data stored in the transmission buffer into a packet data unit with a proper size under control of the transmission controller;

a polling information processor for, when there is a possibility that upper layer data contained the packet data unit will cause an upper layer response message in an opposite direction, generating polling information for ordering a receiver to wait for a predetermined time after receipt of a packet and to transmit an upper layer packet generated for the waiting time along with a status report, and including the polling information in the packet data unit; and

a transmission unit for transmitting the packet data unit including the polling information.

16. The L2 transmitter of claim 15, further comprising:

a retransmission buffer for storing a packet data unit in which the polling information is included.

17. The L2 transmitter of claim 16, wherein when there is a need for retransmission of polling information due to the expiration of a polling timer, the transmission controller controls the retransmission buffer and the framing unit so as to resegment a packet data unit including the polling information stored in the retransmission buffer thereby to generate a new polling packet data unit in which the polling information and the minimum user data are contained.

18. The L2 transmitter of claim 16, wherein when there is a need for resegmented retransmission of a polling packet data unit, the transmission controller controlling the polling information processor so as to check a trigger of polling information and include polling information in a first segment or a last segment according to the trigger.

19. The L2 transmitter of claim 16, wherein after a lapse of a predetermined time after a polling packet data unit was successfully transmitted, the transmission controller starts a predetermined polling timer at a time that the transmitter first received a packet from an opposite L2 device, and starts retransmission of the polling information if no reception status report message is received until the polling timer expires.

20. A Layer 2 (L2) receiver in a communication system having a protocol layer structure, for assembling lower layer data received over a radio channel, transmitting the lower layer data to an upper layer, receiving polling information representative of an indicator for ordering the generation of a status report, and transmitting the status report to a transmitter within a predetermined time, the receiver comprising:

a reception buffer for storing data provided from a lower layer;

a transmission controller for starting a timer and waiting for a predetermined time, when the polling information generates an order to transmit a reception status report and an upper layer packet together; and

a reception status report processor for transmitting an upper layer packet generated for the predetermined time and a reception status report responsive to the polling information together to the transmitter.