METHODS AND APPARATUS FOR FACILITATING ROBUST FORWARD HANDOVER IN LONG TERM EVOLUTION (LTE) COMMUNICATION SYSTEMS
First Claim
1. A method for facilitating a forward handover in a communications system, comprising:
- receiving, at a target base station, a first message from a user terminal indicative of a Random Access Channel (RACH) procedure to initiate access to the target base station;
sending, from the target base station, a second message to the user terminal to initiate access to the target base station;
receiving, at the target base station, a third message comprising a connection reestablishment request including first identity information from the user terminal for retrieval of user context information stored at a source base station;
initiating, at the target base station, retrieval of the user context from the source base station;
sending, from the target base station, in response to failure to retrieve the user context, a fourth message to the user terminal informing the user terminal to continue the forward handover without performing another RACH procedure; and
receiving, at the target base station, a connection request message from the user terminal.
1 Assignment
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Accused Products
Abstract
Method and apparatus for facilitating inter-cell connections, such as during a forward handover or radio link failure (RLF), are disclosed. A user terminal such as a UE may store identity information associated with a source cell, and use this information in accessing target or other cells subsequent to radio link failure so as to facilitate access to context information of the user terminal. A base station may be configured to improve handover performance by associating context information with a newly assigned terminal identity. Handover performance may be enhanced by facilitating connection processing in the event of inability to retrieve user terminal context from a source cell.
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Citations
20 Claims
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1. A method for facilitating a forward handover in a communications system, comprising:
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receiving, at a target base station, a first message from a user terminal indicative of a Random Access Channel (RACH) procedure to initiate access to the target base station; sending, from the target base station, a second message to the user terminal to initiate access to the target base station; receiving, at the target base station, a third message comprising a connection reestablishment request including first identity information from the user terminal for retrieval of user context information stored at a source base station; initiating, at the target base station, retrieval of the user context from the source base station; sending, from the target base station, in response to failure to retrieve the user context, a fourth message to the user terminal informing the user terminal to continue the forward handover without performing another RACH procedure; and receiving, at the target base station, a connection request message from the user terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computer program product comprising a non-transitory computer readable medium including codes executable by a processor of a target base station to:
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receive a first message from a user terminal indicative of a Random Access Channel (RACH) procedure to initiate access to the target base station; send a second message to the user terminal to initiate access to the target base station; receive a third message comprising a connection reestablishment request including first identity information from the user terminal for retrieval of user context information stored at a source base station; initiate retrieval of the user context from the source base station; send, in response to failure to retrieve the user context, a fourth message to the user terminal informing the user terminal to continue a forward handover without performing another RACH procedure; and receive a connection request message from the user terminal
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9. A target base station, comprising:
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a receiver module configured to receive a first message from a user terminal indicative of a Random Access Channel (RACH) procedure to initiate access to the target base station; a transmitter module configured to send a second message to the user terminal to initiate access to the target base station; wherein the receiver module is further configured to receive a third message comprising a connection reestablishment request including first identity information from the user terminal for retrieval of user context information stored at a source base station; a processor module configured to initiate retrieval of the user context from the source base station; wherein the transmitter module is further configured to send, in response to failure to retrieve the user context, a fourth message to the user terminal informing the user terminal to continue a forward handover without performing another RACH procedure; and wherein the receiver module is further configured to receive a connection request message from the user terminal. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A target base station, comprising:
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means for receiving a first message from a user terminal indicative of a Random Access Channel (RACH) procedure to initiate access to the target base station; means for sending a second message to the user terminal to initiate access to the target base station; wherein the means for receiving is further configured to receive a third message comprising a connection reestablishment request including first identity information from the user terminal for retrieval of user context information stored at a source base station; means for initiating retrieval of the user context from the source base station; wherein the means for sending is further configured to send, in response to failure to retrieve the user context, a fourth message to the user terminal informing the user terminal to continue a forward handover without performing another RACH procedure; and wherein the means for receiving is further configured to receive a connection request message from the user terminal. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification