Method and apparatus for reducing latency of LTE uplink transmissions

An apparatus comprising:

• a transceiver configured to receive a downlink control information message in a first subframe, the downlink control information message indicating a resource assignment and a modulation and coding scheme and the downlink control information message indicating a plurality of cyclic shifts from which the apparatus may select one cyclic shift for transmission in a second subframe for an uplink carrier;
• and
• a controller configured to select a cyclic shift from the plurality of indicated cyclic shifts based on a selection criterion,
• wherein the transceiver is configured to transmit a data packet on a physical uplink shared channel in a resource indicated by the resource assignment and modulation and coding scheme, and using a demodulation reference signal based on the selected cyclic shift in the second subframe on the uplink carrier.

A method in a user equipment, the method comprising:

• acquiring configuration information regarding the downlink control information message for a physical uplink shared channel transmission prior to receiving the downlink control information message;
• receiving a downlink control information message on a physical downlink control channel in a first subframe, the downlink control information message indicating a resource assignment and a modulation and coding scheme and indicating a plurality of cyclic shifts, from which the user equipment may select one cyclic shift for transmission in a second subframe for an uplink carrier;
• selecting a cyclic shift from the plurality of indicated cyclic shifts based on a selection criterion;
• and
• transmitting a data packet on the physical uplink shared channel in a resource indicated by the resource assignment and modulation and coding scheme, and using a demodulation reference signal based on the selected cyclic shift in the second subframe on the uplink carrier.