Apparatus and methods for managing hyper frame number (HFN) de-synchronization in radio link control (RLC) unacknowledged mode (UM)

A non-transitory computer-readable medium storing computer-executable code for data communication between a transmitter and a receiver in a radio link control (RLC) unacknowledged mode (UM), comprising:

• code for determining, by the transmitter operating in the RLC UM, a hyper frame number (HFN) de-synchronization condition, wherein the HFN de-synchronization condition is FALSE when at least one protocol data unit (PDU) out of a plurality of successive PDUs is successfully transmitted by the transmitter to the receiver, wherein the HFN de-synchronization condition is TRUE when all of the plurality of successive PDUs are lost, and wherein a number of the plurality of successive PDUs is equal to a full cycle of RLC UM sequence numbers, a multiple of the full cycle of RLC UM sequence numbers, or a number greater than the full cycle of RLC UM sequence numbers;
• and
• code for adjusting, by the transmitter operating in the RLC UM, a transmitter HFN of the transmitter when the HFN de-synchronization condition is TRUE, wherein the adjusted transmitter HFN is used for new PDUs to be transmitted in the RLC UM.

An apparatus for data communication between a transmitter and a receiver in a radio link control (RLC) unacknowledged mode (UM), comprising:

• means for determining, by the transmitter operating in the RLC UM, a hyper frame number (HFN) de-synchronization condition, wherein the HFN de-synchronization condition is FALSE when at least one protocol data unit (PDU) out of a plurality of successive PDUs is successfully transmitted by the transmitter to the receiver, wherein the HFN de-synchronization condition is TRUE when all of the plurality of successive PDUs are lost, and wherein a number of the plurality of successive PDUs is equal to a full cycle of RLC UM sequence numbers, a multiple of the full cycle of RLC UM sequence numbers, or a number greater than the full cycle of RLC UM sequence numbers;
• and
• means for adjusting, by the transmitter operating in the RLC UM, a transmitter HFN of the transmitter when the HFN de-synchronization condition is TRUE, wherein the adjusted transmitter HFN is used for new PDUs to be transmitted in the RLC UM.