Method and apparatus for accessing a random access channel by selectively using dedicated or contention based preambles during handover
First Claim
1. A method implemented in a wireless transmit/receive unit (WTRU), the method comprising:
- receiving, via a source cell associated with a source base station, a handover command, the handover command comprising dedicated preamble configuration information including an indication of a dedicated preamble and a dedicated preamble reservation, wherein the dedicated preamble is used for contention free random access in a target cell associated with a target base station during available random access channel (RACH) opportunities, and wherein the dedicated preamble reservation indicates a set of the available RACH opportunities during which the WTRU can transmit using the dedicated preamble;
initiating a timer in response to the handover command; and
transmitting, to the target cell associated with the target base station, the indicated dedicated preamble during a RACH opportunity comprised in the set of the available RACH opportunities indicated in the dedicated preamble reservation prior to an expiration of the timer; and
transmitting, subsequent to the expiration of the timer and on a condition that RACH access using the dedicated preamble was not successful, a contention based preamble.
0 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for accessing a random access channel (RACH) during handover are disclosed. A handover procedure is initiated and a maximum handover interruption timer is activated. A dedicated preamble is transmitted in an attempt to access the RACH on a condition that the dedicated preamble is reserved in a current random access opportunity and the maximum handover interruption timer has not expired. A contention-based preamble is transmitted in an attempt to access the RACH on a condition that a dedicated preamble is not reserved in a current random access opportunity. If the maximum handover interruption timer has expired, a contention-based preamble is transmitted in an attempt to access the RACH.
110 Citations
12 Claims
-
1. A method implemented in a wireless transmit/receive unit (WTRU), the method comprising:
-
receiving, via a source cell associated with a source base station, a handover command, the handover command comprising dedicated preamble configuration information including an indication of a dedicated preamble and a dedicated preamble reservation, wherein the dedicated preamble is used for contention free random access in a target cell associated with a target base station during available random access channel (RACH) opportunities, and wherein the dedicated preamble reservation indicates a set of the available RACH opportunities during which the WTRU can transmit using the dedicated preamble; initiating a timer in response to the handover command; and transmitting, to the target cell associated with the target base station, the indicated dedicated preamble during a RACH opportunity comprised in the set of the available RACH opportunities indicated in the dedicated preamble reservation prior to an expiration of the timer; and transmitting, subsequent to the expiration of the timer and on a condition that RACH access using the dedicated preamble was not successful, a contention based preamble. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A wireless transmit/receive unit (WTRU) comprising:
-
a transceiver configured to receive, via a source cell associated with a source base station, a handover command, the handover command comprising dedicated preamble configuration information including an indication of a dedicated preamble and a dedicated preamble reservation, wherein the dedicated preamble is used for contention free random access in a target cell associated with a target base station during available random access channel (RACH) opportunities, and wherein the dedicated preamble reservation indicates a set of the available RACH opportunities during which the WTRU can transmit using the dedicated preamble; and a processor configured to; initiate a timer in response to the handover command, transmit, via the transceiver to the target cell associated with the target base station, the indicated dedicated preamble during a RACH opportunity comprised in the set of the available RACH opportunities indicated in the dedicated preamble reservation prior to an expiration of the timer, and transmit, subsequent to the expiration of the timer and on a condition that RACH access using the dedicated preamble was not successful, a contention based preamble via the transceiver. - View Dependent Claims (8, 9, 10, 11, 12)
-
Specification