# US 9,521,669 B2 · HARQ for dynamic change of the TDD UL/DL configuration in LTE TDD systems

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- Number: US 9,521,669 B2
- Document ID: US9521669B2
- Status: Granted
- Kind: B2
- Application number: 13/448,212
- Filed: 2012-04-16
- Published: 2013-10-17
- Granted: 2016-12-13
- Earliest claimed: 2012-04-16
- Assignees: BlackBerry Limited
- Applicants: Yiping Wang; Jun Li; Yi Song
- Inventors: Yiping Wang; Jun Li; Yi Song
- Web page: https://patentgrep.com/patent/US9521669B2

## CPC

- H04W 72/0446: Resources in time domain, e.g. slots or frames
- H04B 7/2656: {for structure of frame, burst}
- H04L 1/1822: involving configuration of automatic repeat request [ARQ] with parallel processes
- H04L 1/1861: {Physical mapping arrangements (for ACK signaling see also H04L5/0053)}
- H04L 5/0055: {Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861)}
- H04L 5/143: {for modulated signals (H04L5/1469 takes precedence)}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Systems, methods, and apparatuses are directed to reconfiguring a time division duplex (TDD) uplink/downlink (UL/DL) configuration. A first TDD UL/DL configuration can be identified for a first radio frame. A second TDD UL/DL configuration can be identified for a second radio frame adjacent the first radio frame. The second TDD UL/DL configuration can be identified based, at least in part, on one or more subframes of the second TDD UL/DL configuration that can communicate hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) indicators for corresponding subframes of the first TDD UL/DL configuration.

## Claims

### Claim 1

A method of reconfiguring a time division duplex (TDD) uplink/downlink (UL/DL) configuration, the method comprising:
identifying, at a base station, a first TDD UL/DL predetermined configuration for a first radio frame;
communicating data using the first TDD UL/DL predetermined configuration in the first radio frame;
in response to a change in traffic ratio between UL and DL transmissions, identifying, at the base station, a second TDD UL/DL predetermined configuration for a second radio frame adjacent the first radio frame, the second TDD UL/DL predetermined configuration identified based, at least in part, on one or more subframes of the second TDD UL/DL predetermined configuration that can communicate at least one hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) indicator for a corresponding subframe of the first TDD UL/DL predetermined configuration, wherein the first TDD UL/DL predetermined configuration supports a greater number of HARQ processes than the second TDD UL/DL predetermined configuration, the HARQ processes are uplink (UL) HARQ processes
communicating data using the second TDD UL/DL predetermined configuration in the second radio frame;
storing excess UL HARQ processes in a queue; and
upon receiving a negative new data indicator, executing a first UL HARQ process of the UL HARQ processes stored in the queue.

### Claim 2 (depends on 1)

The method of claim 1, further comprising communicating an ACK indicator prior to the reconfiguring of the TDD UL/DL predetermined configuration.

### Claim 3 (depends on 1)

The method of claim 1, further comprising reconfiguring the TDD UL/DL predetermined configuration for the second radio frame based on the identified second TDD UL/DL predetermined configuration.

### Claim 4 (depends on 1)

The method of claim 1, wherein the first TDD UL/DL predetermined configuration and the second TDD UL/DL predetermined configuration are defined by an LTE standard.

### Claim 5

A method of reconfiguring a time division duplex (TDD) uplink/downlink (UL/DL) configuration, the method comprising:
identifying, at a base station, a first TDD UL/DL predetermined configuration for a first radio frame;
communicating data using the first TDD UL/DL predetermined configuration in the first radio frame;
in response to a change in traffic ratio between UL and DL transmissions, identifying, at the base station, a second TDD UL/DL predetermined configuration for a second radio frame adjacent the first radio frame, the second TDD UL/DL predetermined configuration identified based, at least in part, on one or more subframes of the second TDD UL/DL predetermined configuration that can communicate at least one hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) indicator for a corresponding subframe of the first TDD UL/DL predetermined configuration, wherein the first TDD UL/DL predetermined configuration supports a greater number of HARQ processes than the second TDD UL/DL predetermined configuration, and the second TDD UL/DL predetermined configuration is associated with a second number of HARQ buffers;
communicating data using the second TDD UL/DL predetermined configuration in the second radio frame; and
executing a second number of HARQ processes associated with the first TDD UL/DL predetermined configuration, the second number of HARQ processes equal to the second number of HARQ buffers.

### Claim 6

A base station for reconfiguring a time division duplex (TDD) uplink/downlink (UL/DL) configuration, comprising:
one or more processors configured to:
identify, at the base station, a first TDD UL/DL predetermined configuration for a first radio frame;
communicate data using the first TDD UL/DL predetermined configuration in the first radio frame;
in response to a change in traffic ratio between UL and DL transmissions, identify, at the base station, a second TDD UL/DL predetermined configuration for a second radio frame adjacent the first radio frame, the second TDD UL/DL predetermined configuration identified based, at least in part, on one or more subframes of the second TDD UL/DL predetermined configuration that can communicate at least one hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) indicator for a corresponding subframe of the first TDD UL/DL predetermined configuration, wherein the first TDD UL/DL predetermined configuration supports a greater number of HARQ processes than the second TDD UL/DL predetermined configuration, the HARQ processes are uplink (UL) HARQ processes
communicate data using the second TDD UL/DL predetermined configuration in the second radio frame;
store excess UL HARQ processes in a queue; and
upon receiving a negative new data indicator, execute a first UL HARQ process of the UL HARQ processes stored in the queue.

### Claim 7 (depends on 6)

The base station of claim 6, wherein the first TDD UL/DL predetermined configuration and the second TDD UL/DL predetermined configuration are defined by an LTE standard.

### Claim 8

A non-transitory computer-readable medium containing instructions which, when executed, cause a computing device to perform operations comprising:
identifying, at a base station, a first time division duplex (TDD) uplink/downlink (UL/DL) predetermined configuration for a first radio frame;
communicating data using the first TDD UL/DL predetermined configuration in the first radio frame;
in response to a change in traffic ratio between UL and DL transmissions, identifying, at the base station, a second TDD UL/DL predetermined configuration for a second radio frame adjacent the first radio frame, the second TDD UL/DL predetermined configuration identified based, at least in part, on one or more subframes of the second TDD UL/DL predetermined configuration that can communicate at least one hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgement (ACK/NACK) indicator for a corresponding subframe of the first TDD UL/DL predetermined configuration, wherein the first TDD UL/DL predetermined configuration supports a greater number of HARQ processes than the second TDD UL/DL predetermined configuration, and the second TDD UL/DL predetermined configuration is associated with a second number of HARQ buffers;
communicating data using the second TDD UL/DL predetermined configuration in the second radio frame; and
executing a second number of HARQ processes associated with the first TDD UL/DL predetermined configuration, the second number of HARQ processes equal to the second number of HARQ buffers.