Protocol synchronization for harq background

A method for Hybrid Automatic Repeat Request (HARQ) link layer protocol synchronization for an uplink transmission between a transmitter and a receiver (20) in a wireless communication system, the method comprising:

• receiving a first protocol data unit in response to a transmitted explicit scheduling grant;
• evaluating the received first protocol data unit for errors;
• transmitting a HARQ feedback message for the received first protocol data unit based on the error evaluation, wherein the HARQ feedback message is a positive acknowledgement for the received first protocol data unit;
• receiving a subsequent second protocol data unit distinct from the first protocol data unit in response to a subsequent explicit scheduling grant transmitted in addition to the HARQ feedback message, wherein the subsequent explicit scheduling grant indicates to the transmitter to be authorized for transmitting the second protocol data unit;
• and
• receiving a re-transmitted first protocol data unit in absence of transmitting a subsequent explicit scheduling grant.

A transmitter for Hybrid Automatic Repeat Request (HARQ) link layer protocol synchronization for an uplink transmission between the transmitter and a receiver in a wireless communication system, the transmitter comprising processing circuitry configured to:

• transmit a first protocol data unit in response to a received explicit scheduling grant;
• receive a HARQ feedback message for the transmitted first protocol data unit;
• transmit a subsequent second protocol data unit distinct from the first protocol data unit in response to a subsequent explicit scheduling grant received in addition to the HARQ feedback message, wherein the subsequent explicit scheduling grant indicates to the transmitter to be authorized for transmitting the second protocol data unit;
• and
• re-transmit the first protocol data unit in absence of receipt of a subsequent explicit scheduling grant upon interpretation of the HARQ feedback message as a negative acknowledgement for the transmitted first protocol data unit.

A receiver for Hybrid Automatic Repeat Request (HARQ) link layer protocol synchronization for an uplink transmission between a transmitter and the receiver in a wireless communication system, the receiver comprising processing circuitry configured to:

• receive a first protocol data unit in response to a transmitted explicit scheduling grant;
• evaluate the received first protocol data unit for errors;
• transmit a HARQ feedback message for the received first protocol data unit based on the error evaluation, wherein the HARQ feedback message is a positive acknowledgement for the received first protocol data unit;
• receive a subsequent second protocol data unit distinct from the first protocol data unit in response to a subsequent explicit scheduling grant transmitted in addition to the HARQ feedback message, wherein the subsequent explicit scheduling grant indicates to the transmitter to be authorized for transmitting the second protocol data unit;
• and
• receive the re-transmitted first protocol data unit in absence of transmission of a subsequent explicit scheduling grant.