Communication in the presence of uplink-downlink configuration change

A method of a user equipment (UE), comprising:

• receiving downlink data wirelessly from a network node in a first frame according to a first uplink-downlink configuration;
• in response to a configuration change that causes a second frame following the first frame to be according to a second, different uplink-downlink configuration, determining a reference uplink-downlink configuration in response to the configuration change;
• sending, in the second frame, an acknowledgement indication for the downlink data according to a timing of the reference uplink-downlink configuration:
• performing communication using ACK/NACK multiplexing;
• and
• in response to determining that the configuration change is to the second uplink-downlink configuration that does not support ACK/NACK multiplexing, switching from using ACK/NACK multiplexing to using ACK/NACK bundling.

A network node comprising:

• a communication interface to communicate with a user equipment (UE), and
• at least one processor configured to:
• detect a configuration change from a first uplink-downlink configuration of a first frame to a second uplink-downlink configuration of a second frame that follows the first frame;
• in response to the configuration change, determine, based on at least one rule, a timing relationship between an uplink grant and a scheduled subframe of a frame for communicating uplink data, the frame for communicating the uplink data being the first frame or the second frame, the at least one rule specifying that the timing relationship of the uplink grant is determined by an uplink-downlink configuration of a frame carrying the uplink grant, unless the configuration change involves one of an enumerated set of configuration combinations, the frame carrying the uplink grant being the first frame or the second frame, therein each configuration combination of the configuration combinations includes a respective pair of different uplink-downlink configurations used in successive frames, wherein the at least one rule further specifies that responsive to the configuration change involving one of the enumerated set of configuration combinations, the timing relationship of the uplink grant is according to one of plural timing relationships of the uplink grant specified for respective configuration combinations of the set of configuration combinations.