Method and apparatus to trigger a random access procedure for carrier aggregation in a wireless communication network

#This disclosure relates generally to a method and apparatus to trigger a random access procedure for carrier aggregation in a wireless communication network.

#In a typical wireless communication network utilizing the 3GPP or 3GPP2 protocol standards, a PDCCH order sent from an Evolved Node B (eNode B) is used to trigger a random access (RA) procedure in a user equipment (UE) to obtain or update the timing advance needed for uplink transmissions. When multiple component carriers (CCs) are configured to a UE, separate timing advances may be needed for different groups of uplink CCs. Therefore, what is needed is a method and apparatus to efficiently trigger the necessary random access procedure.

#A method and apparatus for a base station to trigger a random access procedure for carrier aggregation in a wireless communication system are disclosed. The method includes sending a dedicated radio resource control (RRC) signal to configure a user equipment (UE) with a plurality of secondary component carriers (SCCs) that include uplink (UL) SCCs and/or downlink SCCs for carrier aggregation (CA). The method further includes sending an activation signal to the UE to activate a configured downlink SCC. The method also includes transmitting a physical downlink control channel (PDCCH) order only on the downlink primary component carrier (PCC) to trigger a random access (RA) procedure.

#FIG. 1 shows a multiple access wireless communication system according to one embodiment of the invention.

#FIG. 2 is a block diagram of an embodiment of a transmitter system (also known as the access network (AN)) and a receiver system (also known as access terminal (AT) or user equipment (UE)) according to one embodiment of the invention.

#FIG. 3 shows an alternative functional block diagram of a communication device according to one embodiment of the invention.

#The exemplary wireless communication systems and devices described below employ a wireless communication system, supporting a broadcast service. Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), 3GPP LTE (Long Term Evolution) wireless access, 3GPP2 UMB (Ultra Mobile Broadband), WiMax, or some other modulation techniques.

#In particular, The exemplary wireless communication systems devices described below may be designed to support one or more standards such as the standard offered by a consortium named “3rd Generation Partnership Project” referred to herein as 3GPP, including Document Nos. 3GPP TR 36.814 (“Further Advancements for E-UTRA Physical Layer Aspects (Release 9)”), 3GPP TSG-RAN WG2 R2-095808 (“Activation and Deactivation of Component Carriers”), 3GPP TSG-RAN WG2 R2-095898 (“RACH and carrier aggregation”), 3GPP TSG-RAN WG2 R2-101846 (“Stage 2 description of Carrier Aggregation”), and 3GPP TS 36.321-860 (“Evolved Universal Terrestrial Radio Access (E-UTRA) Medium Access Control (MAC) Protocol Specification (Release 8)”). The standards and documents listed above are hereby expressly incorporated herein.

#FIG. 1 shows a multiple access wireless communication system according to one embodiment of the invention. An access network 100 (AN) includes multiple antenna groups, one including 104 and 106, another including 108 and 110, and an additional including 112 and 114. In FIG. 1, only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal 116 (AT) is in communication with antennas 112 and 114, where antennas 112 and 114 transmit information to access terminal 116 over forward link 120 and receive information from access terminal 116 over reverse link 118. Access terminal (AT) 122 is in communication with antennas 106 and 108, where antennas 106 and 108 transmit information to access terminal (AT) 122 over forward link 126 and receive information from access terminal (AT) 122 over reverse link 124. In a FDD system, communication links 118, 120, 124 and 126 may use different frequency for communication. For example, forward link 120 may use a different frequency then that used by reverse link 118.