HARQ OPERATION FOR MACRO-DIVERSITY TRANSMISSIONS IN THE DOWNLINK

• US 20110305213A1
• Filed: 01/13/2010
• Published: 12/15/2011
• Est. Priority Date: 01/30/2009
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Löhr, Joachim, Golitschek Edler Von Elbwart, Alexander, Gonsa, Osvaldo
• Granted Patent: US 8,855,069 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1822 involving configuration of automatic repeat request [ARQ] with parallel processes
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 2001/0097 Relays

Abstract

The invention relates to a downlink transmission scheme that supports downlink HARQ operation and macro-diversity that is capable of overcoming the problem of HARQ protocol de-synchronization when using HARQ in the downlink with multiple data transmitting network nodes. In this scheme, a distributed HARQ protocol operation for downlink data transmissions involving multiple network nodes is provided, where only one network node is terminating downlink HARQ protocol operation towards to mobile terminal, i.e. retransmissions of a data packet are sent from a single network node, a single HARQ transmitter, to the mobile terminal. The multiple network nodes send a first transmission of the data packet to the mobile terminal in a single transmission time interval using HARQ. One of the multiple network nodes is designated as the HARQ terminating node that controls/handles all retransmissions of the data packet.

Claims

1. A method for transmitting downlink data in a mobile communication system comprising a mobile terminal and at least two network nodes, the network nodes being capable of communicating with the mobile terminal via a wireless interface, the method comprising:

transmitting a data packet and control information for a transmission of the data packet from the first network node to the second network node, wherein the control information indicates whether the first or the second network node terminates a Hybrid Automatic Repeat reQuest (HARQ) protocol used for transmitting the data packet to the mobile terminal,

transmitting by the first network node and the second network node a respective transmission of a data packet to the mobile terminal within one transmission time interval and using one of plural HARQ processes of the HARQ protocol,

receiving from the mobile terminal HARQ feedback on the successful or unsuccessful decoding of the data packet only at the network node terminating the HARQ protocol, and

transmitting all retransmissions of the data packet only from the network node terminating the HARQ protocol to the mobile terminal.

2. The method according to claim 1, further comprising transmitting by the first network node and/or the second network node a respective physical downlink control channel to the mobile terminal, wherein a respective physical downlink control channel'"'"'s information indicates the physical channel resource and the HARQ process on which the transmission of the data packet is transmitted to the mobile terminal.

3. The method according to claim 2, wherein transmitting, by the first network node and/or the second network node, a respective physical downlink control channel to the mobile terminal, comprises the first network node and the second network node each transmitting a physical downlink control channel indicating the physical channel resource and the HARQ process on which the respective transmission of the data packet is transmitted to the mobile, and

the method further comprises receiving said HARQ feedback from the mobile terminal via an physical uplink channel resource configured by Radio Resource Control (RRC) signaling.

4. The mobile terminal according to claim 2, wherein transmitting, by the first network node and/or the second network node, a respective physical downlink control channel to the mobile terminal, comprises the first network node or the second network node each transmitting a physical downlink control channel indicating the physical channel resource and the HARQ process on which the respective transmission of the data packet is transmitted to the mobile, and

the method further comprises receiving said HARQ feedback from the mobile terminal via a physical uplink channel resource linked to the physical downlink control channel resource index on which the physical downlink control channel is received by the mobile terminal.

5. The method according to claim 1, wherein the control information transmitted from the first network node to the second network node comprises a flag indicating whether the first or the second network node terminates a HARQ protocol.

6. The method according to claim 5, wherein the control information transmitted from the first network node to the second network node further indicates the HARQ process to be used for transmitting the data packet to mobile terminal and the value of the new data indicator for the data packet.

7. The method according to claim 6, wherein the control information transmitted from the first network node to the second network node further indicates transport format information of the transmission of the data packet from the second network node to the mobile terminal.

8. The method according to claim 1, wherein transmitting the transmission of the data packet by the first network node and the second network node, comprises the first network node and the second network node simultaneously transmitting the transmission of the data packet within the same transmission time interval.

9. The method according to claim 8, wherein the control information transmitted from the first network node to the second network node further indicates transmission time interval in which the transmission of the data packet is to be sent by the second network node.

10. The method according to claim 8 or 9, wherein the control information transmitted from the first network node to the second network node further indicates the physical shared downlink channel resource and transport format information for transmitting the transmission of the data packet to the mobile terminal and

wherein transmitting the transmission of the data packet by the first network node and the second network node, comprises the first network node to the second network node simultaneously transmit the transmission of the data packet on the same physical channel resource and using the same transport format.

11. The method according to claim 1, further comprising deciding, by the first network node for each data packet to be transmitted to the mobile terminal, whether the first network node or the second network node is to terminate the HARQ protocol for the transmission of the data packet.

13. The method according to claim 11, wherein deciding whether the first network node or the second network node is to terminate the HARQ protocol for the transmission of the data packet comprises the first network node deciding whether the first network node or the second network node is to terminate the HARQ protocol for the transmission of the data packet based on the downlink channel quality reported by the mobile terminal and/or based on radio resource management criteria.

12. (canceled)

14. (canceled)

15. A mobile communication system for transmitting downlink data, the mobile communication system comprising a mobile terminal, a first network node and a second network node, the first network node and the second network node being capable of communicating with the mobile terminal via a wireless interface,

wherein the first network node is adapted to transmit a data packet and control information on whether the first network node or the second network node terminates the Hybrid Automatic Repeat reQuest (HARQ) protocol for a transmission of the data packet to the second network node, wherein the first network node and the second network node are adapted to transmit a respective transmission of a data packet to the mobile terminal within one transmission time interval and using one of plural HARQ processes of the HARQ protocol, and

wherein only the HARQ terminating entity receives HARQ feedback on the successful or unsuccessful decoding of the data packet from the mobile terminal and transmits all retransmissions of the data packet from the network node terminating the HARQ protocol to the mobile terminal.

16. (canceled)

17. A mobile terminal for receiving downlink data in a mobile communication system, the mobile terminal comprising:

a receiver adapted to receive from a first network node and a second network node a respective transmission of a data packet within a single transmission time interval,

a processing unit adapted to combine the transmissions of the data packet received from the first network node and the second network node,

a decoder adapted to decode the combined transmissions of the data packet, and

a transmitter adapted to transmit Hybrid Automatic Repeat reQuest (HARQ) feedback only to a HARQ terminating entity being either the first network node or the second network node, wherein the HARQ feedback indicates whether the data packet has been successfully decoded,

wherein the mobile terminal is adapted to receive all retransmissions for the data packet only from the HARQ terminating entity.

18. The mobile terminal according to claim 17, wherein the receiver is adapted to receive Radio Resource Control (RRC) signaling indicating a physical channel resource to be used for sending HARQ feedback related to the transmissions of the data packet to the network node terminating the HARQ protocol, and

wherein the transmitter is adapted to transmit the HARQ feedback for the transmission of the data packet to the network node terminating the HARQ protocol using the physical channel resource configured by the RRC signaling, if a respective physical downlink control channel for the transmissions of the data packet is received from the first network node and the second network node.

19. The mobile terminal according to claim 17 or 18, wherein the transmitter is adapted to transmit HARQ feedback related to transmissions of the data packets on a physical uplink channel resource linked to the physical downlink channel resource index of a physical downlink control channel, if only one physical downlink control channel is received for a transmission of the data packet.

20. The mobile terminal according to claim 17 or 18, further comprising a measuring unit adapted to measure the downlink channel quality from the first network node to the mobile terminal,

wherein the transmitter is adapted to transmit to the first network node the measured channel quality of the downlink channel used to transmit the downlink data from the first network node to the mobile terminal.

21. The mobile terminal according to claim 20, wherein the measuring unit is adapted to further measure the downlink channel quality from the second network node to the mobile terminal, and

wherein the transmitter is adapted to transmit to the first network node the measured channel quality of the downlink channel used to transmit the downlink data from the second network node to the mobile terminal.

22. A network node for use in a mobile communication system, wherein the network nodes is capable of communicating with the mobile terminal via a wireless interface, the network node comprising:

a transmitter adapted to transmit a data packet and control information for a transmission of the data packet to another network node, wherein the control information indicates whether the network node or the other network node terminates a Hybrid Automatic Repeat reQuest (HARQ) protocol used for transmitting the data packet to the mobile terminal and a transmission time interval in which the network node and the other network node are to transmit a transmission of the data packet to the mobile terminal,

wherein the transmitter is adapted to for transmitting a respective transmission of a data packet to the mobile terminal within said transmission interval and using one of plural HARQ processes of the HARQ protocol, and

a receiver adapted to receive from the mobile terminal HARQ feedback on the successful or unsuccessful decoding of the data packet, if the network node is terminating the HARQ protocol and

wherein the transmitter is adapted to transmit all retransmissions of the data packet only to the mobile terminal, if the network node is terminating the HARQ protocol.

23. The network node according to claim 22, further comprising a processing unit for deciding whether the network node or the other network node is to terminate the HARQ protocol for the transmission of the data packet, wherein the decision unit is adapted to perform the decision for each data packet to be transmitted to the mobile terminal.

24-26. -26. (canceled)