Selective packet retransmission with timing control at the transmitter end

• US 20030023916A1
• Filed: 06/03/2002
• Published: 01/30/2003
• Est. Priority Date: 06/06/2001
• Status: Active Grant

• Current Assignee: Video Streaming Solutions LLC (Acacia Research Corporation)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Reme, Jean-Marc, Delmas, Gilles
• Granted Patent: US 6,922,805 B2
• Time in Patent Office: Days
• US Class Current: 714/748
• CPC Class Codes: H04L 1/1678 where the control information is for timing, e.g. time stamps
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements

Abstract

The invention proposes a mechanism for retransmitting packets which comprises a step for checking at the transmitter whether the retransmitted packet will be received by the receiver in time to be processed.

To this end, the receiver sends in its retransmission request the processing time indication of the packet being processed at the receiver when the request is transmitted. At the transmitter end, this processing time indication is compared with the processing time indication of the packet to be retransmitted so as to authorize or block its retransmission.

Claims

1. A transmission system comprising at least a transmitter (10) and a receiver (20),

said transmitter comprising means of transmitting packets (TX1) that contain an indication of packet processing time (T_T, T_L), and means of receiving (RX1) retransmission requests (RR) relating to a packet to be retransmitted (Q_L),

said receiver comprising means of receiving (RX3) packets, means of processing the packets received (DEC), and means of transmitting (TX3) retransmission requests relating to a packet to be retransmitted,

characterized in that:

at least certain of said retransmission requests contain a recovery data (SN_T;

T_T) allowing the recovery of the processing time indication (T_T) of the packet (Q_T) being processed at the moment that the retransmission request (RR) is transmitted,

and said transmitter comprises means (E1) of recovering a processing time indication (T_T) from a recovery data (SN_T, T_T) contained in a received retransmission request, and means (E1) of comparing the recovered processing time indication and the processing time indication of the packet to be retransmitted, so as to authorize or block the retransmission of the packet to be retransmitted.

2. A transmission system as claimed in claim 1, characterized in that said packets contain a sequence number (SN), said transmitter comprises a memory (TBL) for storing data relating to at least certain packets, in particular the sequence numbers of said packets, and means of erasing from said memory the data relating to at least some of the packets that have a sequence number less than or equal to that of a packet to be retransmitted, when the retransmission of said packet to be retransmitted is blocked.

3. A transmission system as claimed in claim 1, characterized in that said recovery data is the processing time indication of the packet being processed at the moment that the retransmission request is transmitted.

4. A transmission system as claimed in claim 1, characterized in that said packets contain a sequence number, said recovery data is the sequence number of the packet being processed at the moment that the retransmission request is transmitted, and said transmitter comprises means of comparing the sequence number contained in a retransmission request and the sequence number of the packet to be retransmitted when the recovered processing time indication and the processing time indication of the packet to be retransmitted are identical, so as to authorize or block the retransmission of the packet to be retransmitted.

5. A terminal (30) comprising means of receiving (RX3) packets containing an indication of packet processing time (T), means (DEC) of processing the packets received, and means (TX3) of transmitting retransmission requests relating to a packet,

characterized in that at least some of said retransmission requests contain a recovery data (T_T;

SN_T) allowing the recovery of the processing time indication of the packet being processed at the moment that the retransmission request is transmitted (T_T).

6. A terminal as claimed in claim 5, characterized in that said recovery data is the processing time indication of the packet being processed at the moment that the retransmission request is transmitted.

7. A terminal as claimed in claim 5, characterized in that said packets contain a sequence number, and said recovery data is the sequence number of the packet being processed when the retransmission request is transmitted.

8. A terminal as claimed in claim 5, characterized in that said transceiver device is a radio device.

10. A server as claimed in claim 7, characterized in that, said packets containing a sequence number, it comprises a memory (TBL) for storing data relating to at least certain packets, in particular the sequence numbers of said packets, and means of erasing from said memory the data relating to at least some of the packets which have a sequence number less than or equal to that of a packet to be retransmitted, when the retransmission of said packet to be retransmitted is blocked.

9. A server (10) comprising means (TX1) of transmitting packets containing an indication of packet processing time (T), and means (RX1) of receiving a retransmission request (RR) relating to a packet to be retransmitted (Q_L), transmitted by a terminal (30) equipped with means (RX3) of receiving packets and means (TX3) of processing the packets received,

characterized in that, at least certain of said retransmission requests contain a recovery data (SN_T;

T_T) allowing the recovery of the processing time indication of the packet being processed at the moment that the packet retransmission request is transmitted (T_T), and said server comprises means (E1 of recovering a processing time indication from a recovery data contained in a received retransmission request, and means (E1 of comparing the recovered processing time indication and the processing time indication of the packet to be retransmitted, so as to authorize or block the retransmission of the packet to be retransmitted.

11. A method of retransmitting a packet intended to be implemented in a transmission system comprising a transmitter (10) intended to transmit packets containing an indication of packet processing time, and a receiver (30) intended to receive packets and process the packets received, said method comprising a step (S1;

S1′

) transmission of a retransmission request relating to said packet (RR), and a step (S2;

S2′

) for reception of said retransmission request by the transmitter, characterized in that said retransmission request contains a data (SN_T;

T_T) for recovering the processing time indication of the packet being processed at the moment that the packet retransmission request is transmitted (T_T), and in that said method comprises;

a step (S3;

S3′

) for recovery of the processing time indication from the recovery data contained in the received retransmission request,

a step (S6;

S6′

) for comparison of the recovered processing time indication and the processing time indication of the packet to be retransmitted, so as to authorize (A1;

A5;

A8) or block (A2;

A4;

A7) the retransmission of the packet to be retransmitted.

12. A program comprising instructions for implementing a packet retransmission method as claimed in claim 11 when it is executed by a processor.