Method and apparatus for handover in a wireless communication system

An apparatus that facilitates a random access procedure in a wireless communication system, the apparatus comprising:

• means for receiving a connection request from a terminal during an access phase of a random access procedure associated with a handover between the terminal and the apparatus;
• means for submitting one or more responses from the apparatus to the terminal during the access phase of the random access procedure that indicate a system frame number (SFN) associated with the apparatus;
• and
• means for inserting the SFN associated with the apparatus into at least one of a header, sub-header, or payload associated with one of the one or more responses.

A computer program product, comprising:

• a non-transitory computer-readable medium, comprising:
• code for identifying a user equipment (UE) to be attached during a random access procedure associated with a handover between the UE and a target evolved Node B (eNB);
• code for determining a system frame number (SFN) of the target eNB;
• code for configuring one or more Random Access Responses (RARs) to include the SFN by inserting the SFN into a header, sub-header or payload associated with the one or more RARs;
• and
• code for transmitting the one or more RARs from the target eNB to the UE during an access phase associated with the random access procedure.

A method used in a wireless communication system, the method comprising:

• constructing an 8-bit medium access control (MAC) sub-header, the MAC sub-header comprising a 1-bit Extension (E) field, a 1-bit Type (T) field, a 1-bit system frame number (SFN) indicator (S) field, a 1-bit Reserved (R) field, and a 4-bit Backoff Indicator (BI) field, a system frame number (SFN) identified by the 1-bit SFN indicator S field being associated with a target evolved Node B (eNB);
• setting the T field to a value that indicates presence of the BI field in the MAC sub-header;
• setting the S field to a value that indicates presence of a SFN in the BI field in place of BI information;
• placing a first portion of the SFN in the BI field of the MAC sub-header;
• placing a second portion of the SFN in an octet immediately following the BI field of the MAC sub-header;
• and
• transmitting, by the target eNB, the MAC sub-header within at least one MAC Protocol Data Unit (PDU) to a terminal during an access phase of a random access procedure associated with a handover between a user equipment (UE) and the target eNB.

A method for accessing a target cell in connection with a random access procedure, comprising:

• submitting an access request to a target cell during an access phase of a random access procedure associated with a handover between a user equipment (UE) and a target evolved Node B (eNB) of the target cell;
• receiving one or more responses to the access request from the target cell during the access phase of the random access procedure that indicate inclusion of a system frame number (SFN) for the eNB of the target cell;
• and
• determining the SFN for the eNB of the target cell by analyzing at least one of a header, sub-header, or payload associated with the one or more received responses.

An apparatus that facilitates a random access procedure in a wireless communication system, the apparatus comprising:

• means for receiving a Random Access Response (RAR) from a target base station during a random access procedure associated with a handover between the apparatus and the target base station, in which the RAR includes a system frame number (SFN) for the target base station;
• means for analyzing the received RAR to determine the SFN for the target base station;
• and
• means for identifying the SFN for the target base station from at least one of a header, sub-header or payload associated with the received RAR.

A computer program product, comprising:

• a non-transitory computer-readable medium, comprising:
• code for receiving one or more Random Access Responses (RARs) from a target cell of a random access procedure during an access phase of the random access procedure, the random access procedure being associated with a handover between a user equipment (UE) and an evolved Node B (eNB) of the target cell;
• code for identifying a RAR from the target cell that indicates a system frame number (SFN) of the target cell;
• and
• code for determining the SFN of the eNB of the target cell from at least one of a header, sub-header, or payload associated with the identified RAR.

An integrated circuit that executes computer-executable instructions for identifying system frame number (SFN) information associated with a target cell during a random access procedure, the instructions comprising:

• transmitting an access request to a target cell during a random access procedure associated with a handover between a user equipment (UE) and a target evolved node B (eNB) of the target cell;
• receiving one or more responses to the access request from the target cell during the random access procedure;
• identifying an indication in at least one of the responses that a SFN for the target cell is included in an indicated response;
• and
• obtaining the SFN of the eNB for the target cell from at least one of a header, sub-header or payload associated with the indicated response.