Preemptive retransmissions on listen-before-talk cells

Patent metadata

Field	Value
Publication number	US-2016174259-A1
Application number	US-201514962503-A
Country	US
Kind code	A1
Filing date	Dec 8, 2015
Priority date	Dec 10, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

Systems and methods are described herein relating to preemptive retransmission of a transport block in successive subframes on, e.g., a Listen-Before-Talk (LBT) cell. Embodiments of a method of operation of a radio node of a cellular communications network are disclosed. The radio node serves an LBT cell. In some embodiments, the method of operation of the radio node comprises transmitting a transport block in a first subframe on the LBT cell and retransmitting the transport block in a second subframe (e.g., on the LBT cell), where the second subframe is adjacent, in time, to the first subframe. In embodiments in which the retransmission of the transport block is on the LBT cell (or another LBT cell), the time span of a transmission burst can be extended to a maximum allowed burst duration.

First claim

1 . A method of operation of a radio node of a cellular communications network, the radio node serving a Listen-Before-Talk, LBT, cell, comprising:
transmitting a transport block in a first subframe on the LBT cell; and retransmitting the transport block in a second subframe, the second subframe being adjacent, in time, to the first subframe.

2 . The method of claim 1 wherein retransmitting the transport block in the second subframe comprises preemptively retransmitting the transport block in the second subframe without first receiving an indication that retransmission of the transport block transmitted in the first subframe is needed.

3 . The method of claim 2 wherein preemptively retransmitting the transport block in the second subframe comprises preemptively retransmitting the transport block in the second subframe according to a Hybrid Automatic Repeat Request, HARQ, procedure.

4 . The method of claim 1 wherein retransmitting the transport block in the second subframe comprises transmitting a redundancy version of the transport block in the second subframe that is different than that transmitted in the first subframe.

5 . The method of claim 1 wherein retransmitting the transport block in the second subframe comprises retransmitting the transport block in the second subframe using time-frequency resources within the second subframe that are the same as time-frequency resources used for transmission of the transport block within the first subframe.

6 . The method of claim 1 wherein retransmitting the transport block in the second subframe comprises retransmitting the transport block in the second subframe using time-frequency resources within the second subframe that are different than time-frequency resources used for transmission of the transport block within the first subframe.

7 . The method of claim 1 wherein the radio node is a radio access node, transmitting the transport block in the first subframe comprises transmitting a downlink transport block to a wireless device in the first subframe, and retransmitting the transport block in the second subframe comprises retransmitting the downlink transport block to the wireless device in the second subframe.

8 . The method of claim 7 further comprising:
transmitting a single resource allocation grant for transmission of the downlink transport block in the first subframe and retransmission of the downlink transport block in the second subframe.

9 . The method of claim 8 wherein transmitting the single resource allocation grant comprises transmitting the single resource allocation grant on a cell other than the LBT cell.

10 . The method of claim 9 wherein the cell is a primary cell with respect to downlink carrier aggregation for the wireless device, and the LBT cell is a secondary cell with respect to downlink carrier aggregation for the wireless device.

11 . The method of claim 10 wherein the primary cell operates in a licensed frequency spectrum.

12 . The method of claim 1 wherein the radio node is a wireless device, transmitting the transport block in the first subframe comprises transmitting an uplink transport block to a radio access node in the first subframe, and retransmitting the transport block in the second subframe comprises retransmitting the uplink transport block to the radio access node in the second subframe.

13 . The method of claim 12 further comprising:
receiving a single resource allocation grant for transmission of the uplink transport block in the first subframe and retransmission of the uplink transport block in the second subframe.

14 . The method of claim 13 wherein receiving the single resource allocation grant comprises receiving the single resource allocation grant on a cell other than the LBT cell.

15 . The method of claim 14 wherein the cell is a primary cell with respect to downlink carrier aggregation for the wireless device, and the LBT cell is a secondary cell with respect to downlink carrier aggregation for the wireless device.

16 . The method of claim 15 wherein the primary cell operates in a licensed frequency spectrum.

17 . The method of claim 7 wherein the single resource allocation grant for transmission of the transport block in the first subframe and retransmission of the transport block in the second subframe comprises an indication of a sequence of redundancy versions of the transport block that the wireless device is to expect in successive subframes comprising the first subframe and the second subframe.

18 . The method of claim 7 wherein the single resource allocation grant for transmission of the transport block in the first subframe and retransmission of the transport block in the second subframe is comprised in a Downlink Control Information, DCI, message that is scrambled with a Radio Network Temporary Identifier, RNTI, that indicates that preemptive retransmissions will be used for the single resource allocation grant.

19 . The method of claim 18 wherein a number of preemptive transmissions in successive subframes for the single resource allocation grant is predefined.

20 . The method of claim 7 wherein the single resource allocation grant for transmission of the transport block in the first subframe and retransmission of the transport block in the second subframe comprises an indication that the single resource allocation grant is valid for multiple successive subframes comprising the first subframe and the second subframe.

21 . The method of claim 1 wherein:
both transmission of the transport block in the first subframe and retransmission of the transport block in the second subframe are scheduled by a single resource allocation grant that is provided on a cell other than the LBT cell;
the cell on which the single resource allocation grant is provided and the LBT cell are Time Division Duplexing, TDD, cells in which transmissions in a particular subframe on the LBT cell are normally scheduled by resource allocation grants transmitted in a corresponding downlink subframe on the cell; and
the second subframe is a subframe on the LBT cell on which transmissions could normally not be scheduled because a corresponding subframe on the cell is an uplink subframe.

22 . The method of claim 1 wherein retransmitting the transport block comprises retransmitting the transport block in one or more additional subframes on the LBT cell, where the one or more additional subframes are adjacent, in time, to one another and the one or more additional subframes comprise the second subframe that is adjacent, in time, to the first subframe.

23 . The method of claim 22 wherein the one or more additional subframes further comprise a third subframe that is adjacent, in time, to the second subframe.

24 . The method of claim 22 wherein a number of the one or more additional subframes is variable.

25 . The method of claim 24 wherein the number of the one or more additional subframes is defined by higher-layer signaling.

26 . The method of claim 22 wherein the one or more additional subframes comprises two or more additional subframes, and retransmitting the transport block in the one or more additional subframes comprises transmitting a different redundancy version of the transport block in each of the two or more additional subframes.

27 . The method of claim 22 wherein retransmitting the transport block in the one or more additional subfram

Assignees

• Ericsson Telefon Ab L M

Inventors

• Mukherjee Amitav
• Cheng Jung-Fu
• Falahati Sorour
• Koorapaty Havish
• Larsson Daniel
• Yang Yu

Classifications

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W72/042

  Electricity · mapped topic

• H04L5/1469

  using time-sharing · CPC title

• H04W74/0816 Primary

  with collision avoidance · CPC title

• H04L1/1816

  with retransmission of the same, encoded, message · CPC title