Unequal error protection in a packet transmission system

• US 20040132442A1
• Filed: 05/23/2003
• Published: 07/08/2004
• Est. Priority Date: 12/04/2000
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Li, Hui, Wenger, Fabian, Lindskog, Jan, Zimmermann, Gerd, Pauli, Mathias
• Granted Patent: US 7,333,449 B2
• Time in Patent Office: Days
• US Class Current: 455/423
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence

Abstract

In a packet transmission system, especially wireless transmission system, where data is transmitted in packets at different error protection levels and where the error protection level of one packet (=the succeeding packet) may differ from the error protection level of a preceding packet without providing code termination between the said preceding and the said succeeding packet the performance may degrade in case a different error protection level is used by the preceding packet and the succeeding packet. The invention proposes in these cases to insert a supplementary packet between the preceding and the succeeding packet whereby the error protection level of the supplementary packet is higher than the lowest error protection level that is used either by the preceding or the succeeding packet.

Claims

1. Packet transmission system (1, 2, 3, 4, 5), especially wireless transmission system, where data is transmitted in packets at different error protection levels and where the error protection level of one packet (PDU_N+1) (=the succeeding packet) may differ from the error protection level of a preceding packet (PDU_N) without providing code termination between the said preceding (PDU_N) and the said succeeding packet(PDU_N+1),

characterized in that

in case a different error protection level is used by the preceding packet (PDUN) and the succeeding packet(PDU_N+1) a supplementary packet (DUMMY-PDU) is inserted between the preceding and the succeeding packet whereby the error protection level of the supplementary packet (DUMMY-PDU) is higher than the lowest error protection level that is used either by the preceding (PDU_N) or the succeeding (PDU_N+1) packet.

2. Packet transmission system according to claim 1 whereby the error protection level of the supplementary packet (DUMMY-PDU) is equal to the error protection level of the highest error protection level either of the preceding or the succeeding packet.

3. Packet transmission system according to claims 1 or 2 whereby the error protection level is defined by the code rate of the packets.

4. Packet transmission system according to claims 1 or 2 whereby as error protection level is defined by the modulation scheme used for a packet

5. Packet transmission system according to claims 1 or 2 whereby the error protection level is defined by a combination of the code rate and the modulation scheme used for a packet.

6. Packet transmission systems according to one of claims 1 to 5 wherein the supplementary packet (DUMMY-PDU) is a dummy packet.

7. Packet transmission system according to one of claims 1 to 5 wherein the supplementary packet (PDU_N+1*) is a repetition of one of the preceding packet (PDU_N) or the succeeding (PDU_N+1) packet.

9. Packet transmission system according to one of claims 1 to 8 whereby the packet transmission system is a packet transmission system according to ETSI TR 101 683, the so-called “

HIPERLAN type 2”

standard.

8. Packet transmission system, especially wireless transmission system, where data is transmitted in packets at different error protection levels and where the error protection level of one packet (PDU_N+1) (=the succeeding packet) may differ from the error protection level of a preceding packet (PDU_N) without providing code termination between the said preceding and the said succeeding packet,

characterized in that

bits which are reserved for future use (FU) are used for code termination.

10. Device for a packet transmission system, especially wireless transmission system, comprising a transmitter, where data is transmitted by said transmitter in packets at different error protection levels and where the error protection level of one packet (PDU_N+1) (=the succeeding packet) may differ from the error protection level of a preceding packet(PDU_N) without providing code termination between the said preceding and the said succeeding packet,

characterized in that

the transmitter inserts a supplementary packet (DUMMY-PDU) in case error protection level used by the preceding packet (PDU_N) and the succeeding packet(PDU_N+1) whereby the error protection level of the supplementary packet (DUMMY-PDU) is higher than the lowest error protection level that is used either by the preceding or the succeeding packet.

11. Device for a packet transmission system according to claim 10 whereby the transmitter marks the inserted packet as a supplementary packet.

13. Device for a packet transmission system (1, 2, 3, 4, 5) according to one of claims 10-12 whereby the device is a mobile terminal (2) or a access point (4) respectively.

14. Device for a packet transmission system (1, 2, 3, 4, 5) according to claim 13 whereby the mobile terminal (2) or the access point (4) accords to ETSI TR 101 683, the so-called HIPERLAN type 2 standard.

12. Device for a packet transmission system, especially wireless transmission system, comprising a receiver that is designed to demodulate and decode packets that have been send at different error protection levels

characterized in that

the receiver discards packets which have been marked (DUMMY-PDU) as to be inserted between packets of different error protection levels.