Flexible subframes

• US 9,319,130 B2
• Filed: 09/25/2013
• Issued: 04/19/2016
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Parkvall, Stefan, Astely, David, Dahlman, Erik, Nystrom, Johan, Rahman, Imadur, Seln, Yngve, Skld, Johan
• Primary Examiner(s): Shah, Chirag
• Assistant Examiner(s): REDDIVALAM, SRINIVASA R
• Application Number:
  US14/036,471
• Publication Number:
  US 20140022966A1
• Time in Patent Office: 937 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management

Abstract

The technology disclosed provides the ability for a subframe to be configured as a “flexible” subframe. As a result, at least three different types of subframes in a TDD system may be configured: a downlink (“DL”) subframe, an uplink (“UL”) subframe, and a “flexible” subframe. While the DL and UL subframes are preconfigured for each frame instance, the flexible subframes are dynamically allocated to be an uplink subframe in one instance of a frame and a downlink subframe in another instance of the frame.

Claims

1. A radio terminal for use in a radio communications network, comprising:

electronic circuitry configured to process data for or from a frame structure associated with a macro cell, wherein the frame structure includes one or more downlink subframes preconfigured as a downlink subframe, one or more uplink subframes preconfigured as an uplink subframe, and one or more flexible subframes, where a flexible subframe is dynamically allocated to be an uplink subframe in one instance of a frame and a downlink subframe in another frame instance based at least in part on whether transmissions in the macro cell during the flexible subframe will interfere with transmissions in a pico cell located in the macro cell;

receive circuitry configured to;

receive information indicating when a particular flexible subframe should be interpreted or used as an uplink subframe or a downlink subframe; and

receive and process information sent by a base station in the particular flexible subframe when the received information indicates the particular flexible subframe should be interpreted or used as a downlink subframe; and

transmit circuitry configured to;

transmit information in an uplink direction using the particular flexible subframe as an uplink subframe when the received information indicates the particular flexible subframe should be interpreted or used as an uplink subframe; and

transmit information directly to another radio terminal thereby bypassing the base station using a second flexible subframe.

2. The radio terminal in claim 1, wherein the base station and the radio terminal communicate using time division duplex.

3. The radio terminal in claim 1, wherein the receive circuitry is configured to receive the information indicating when the particular subframe should be interpreted or used as an uplink subframe or a downlink subframe in a subframe prior to the particular flexible subframe.

4. The radio terminal in claim 3, wherein the radio terminal is configured to interpret all flexible subframes as downlink subframes unless the received information indicates that the particular flexible subframe should be interpreted or used as an uplink subframe.

5. The radio terminal in claim 1, wherein the transmit circuitry is configured to transmit feedback signaling only in a subframe preconfigured as an uplink subframe and not in a flexible subframe.

6. The radio terminal in claim 1, wherein the electronic circuitry is configured to vary use of one or more flexible subframes in accordance with traffic demand.

7. The radio terminal of claim 1, wherein the particular flexible subframe is initially a downlink subframe, and the received information indicating when the particular flexible subframe should be interpreted or used as an uplink subframe or a downlink subframe comprises information indicating that the particular flexible subframe should be interpreted or used as an uplink subframe for subsequent transmissions between the radio terminal and the base station.

8. The radio terminal of claim 1, wherein the particular flexible subframe is initially an uplink subframe, and the received information indicating when the particular flexible subframe should be interpreted or used as an uplink subframe or a downlink subframe comprises information indicating that the particular flexible subframe should be interpreted or used as a downlink subframe for subsequent transmissions between the radio terminal and the base station.

9. A method for a radio terminal in a radio communications network, comprising:

processing data, in electronic circuitry, for or from a frame structure associated with a macro cell, wherein the frame structure includes one or more downlink subframes preconfigured as a downlink subframe, one or more uplink subframes preconfigured as an uplink subframe, and one or more flexible subframes, where a flexible subframe is dynamically allocated to be an uplink subframe in one instance of a frame and a downlink subframe in another frame instance based at least in part on whether transmissions in the macro cell during the flexible subframe will interfere with transmissions in a Pico cell located in the macro cell;

receiving and processing with a receiver information indicating when a particular subframe should be interpreted or used as an uplink subframe or a downlink subframe;

receiving and processing with a receiver information sent by a base station in the particular flexible subframe when the received information indicates the particular flexible subframe should be interpreted or used as a downlink subframe;

transmitting with a transmitter information in an uplink direction using the particular flexible subframe as an uplink subframe when the received information indicates the particular flexible subframe should be interpreted or used as an uplink subframe; and

transmitting information directly to another radio terminal thereby bypassing the base station using a second flexible subframe.

10. The method in claim 9, wherein the base station and the radio terminal communicate using time division duplex.

11. The method in claim 9, further comprising receiving the information indicating when the particular subframe should be interpreted or used as an uplink subframe or a downlink subframe in a subframe prior to the particular flexible subframe.

12. The method in claim 9, further comprising interpreting all flexible subframes as downlink frames unless the received indicates that the particular flexible subframe should be interpreted or used as an uplink subframe.

13. The method in claim 9, further comprising transmitting feedback signaling only in a subframe preconfigured as an uplink subrame and not in a flexible subframe.

14. The method in claim 9, further comprising varying use of one or more flexible subframes in accordance with traffic demand.

15. The method of claim 9, wherein the particular flexible subframe is initially a downlink subframe, and the received information indicating when the particular flexible subframe should be interpreted or used as an uplink subframe or a downlink subframe comprises information indicating that the particular flexible subframe should be interpreted or used as an uplink subframe for subsequent transmissions between the radio terminal and the base station.

16. The method of claim 9, wherein the particular flexible subframe is initially an uplink subframe, and the received information indicating when the particular flexible subframe should be interpreted or used as an uplink subframe or a downlink subframe comprises information indicating that the particular flexible subframe should be interpreted or used as a downlink subframe for subsequent transmissions between the radio terminal and the base station.