User equipment and base station in carrier aggregation system, and call admission control method for use with the user equipment and base station

Abstract

Disclosed are user equipment and a base station in a carrier aggregation system, and a call admission method thereof. The user equipment includes a plurality of physical layers, and the base station provides multiple component carriers. When messages for connection setup are transmitted and received between the user equipment and base station, the messages include information about what component carriers are selected by the physical layers, information about what component carriers are selectable by the physical layers, and information about calculations for uplink timing alignment, and call admission control and load balancing is performed based on the information included in the messages. Accordingly, in the carrier aggregation system, quicker call admission and load balancing are achieved.

1 . User equipment in a carrier aggregation system which provides multiple component carriers, the user equipment comprising:
 a connection setup requesting unit to transmit a connection setup request message including information about one or more physical layers for communication with the respective component carriers; and   a connection establishing unit to receive a response to the connection setup request message and to change component carriers selected by the physical layers to other component carriers or establish uplink timing alignment between the component carriers selected by the physical layers, based on the response to the connection setup request message.   
     
     
         2 . The user equipment of  claim 1 , wherein the information about the physical layers includes information about the number of the physical layers or information about what component carriers are selected by the physical layers. 
     
     
         3 . The user equipment of  claim 1 , wherein the connection setup requesting unit designates a physical layer of the physical layers as a primary physical layer, and transmits the connection setup request message using a random preamble of a component carrier selected by the primary physical layer. 
     
     
         4 . The user equipment of  claim 1 , wherein the connection setup requesting unit designates a physical layer of the physical layers as a primary physical layer, and the connection establishing unit, when receiving a connection setup rejection message, controls the primary physical layer to select another component carrier. 
     
     
         5 . The user equipment of  claim 1 , wherein the connection setup requesting unit designates a physical layer of the physical layers as a primary physical layer, and the connection establishing unit establishes, when receiving a connection setup admission message, uplink timing alignment between a component carrier selected by the primary physical layer and component carriers selected by the remaining physical layers except for the primary physical layer. 
     
     
         6 . A base station in a carrier aggregation system which provides multiple component carriers, the base station comprising a call admission unit to receive a connection setup request message from user equipment, and to transmit a connection setup admission message or a connection setup rejection message, including additional information, depending on whether each component carrier fulfills the requirements of the user equipment. 
     
     
         7 . The base station of  claim 6 , wherein the additional information includes at least one piece of information about what component carriers are selectable by physical layers included in the user equipment, information about calculations for uplink timing alignment between the component carriers, or information about a dedicated preamble of each component carrier. 
     
     
         8 . The base station of  claim 6 , wherein when a component carrier selected by a primary physical layer which is one of a plurality of physical layers included in the user equipment does not fulfill the requirements of the user equipment, the call admission unit transmits, to the user equipment, a connection setup rejection message including information about selectable component carriers in order to allow the primary physical layer to select another component carrier. 
     
     
         9 . The base station of  claim 6 , wherein when all component carriers selected by a plurality of physical layers included in the user equipment fulfill the requirements of the user equipment, the call admission unit transmits, to the user equipment, a connection setup admission message including information about calculations for uplink timing alignment or information about dedicated preambles of the respective component carriers. 
     
     
         10 . The base station of  claim 6 , wherein when a component carrier selected by a primary physical layer which is one among a plurality of physical layers included in the user equipment fulfills the requirements of the user equipment but component carriers selected by the remaining physical layers except for the primary physical layer do not fulfill the requirements of the user equipment, the call admission unit transmits, to the user equipment, a connection setup admission message including information about what component carriers are selectable by the remaining physical layers, information about calculations for uplink timing alignment between the component carriers selectable by the remaining physical layers and the component carrier selected by the primary physical layer, or information about dedicated preambles of the respective component carriers. 
     
     
         11 . The base station of  claim 6 , wherein when additional allocation of a component carrier is needed after connection setup is completed, the call admission unit transmits information about another component carrier to the user equipment. 
     
     
         12 . A method in which user equipment performs a call admission procedure in a carrier aggregation system which provides multiple component carriers, comprising:
 transmitting a connection setup request message including information about one or more physical layers for communications with the respective component carriers, to a base station; and   receiving a response to the connection setup request message from the base station, and changing component carriers selected by the physical layers to other component carriers or establishing uplink timing alignment between the component carriers selected by the physical layers.   
     
     
         13 . The method of  claim 12 , wherein the connection setup request message is transmitted to the base station using a random preamble of a component carrier selected by a primary physical layer which is designated among a plurality of physical layers included in the user equipment. 
     
     
         14 . The method of  claim 12 , wherein the information about the physical layers includes information about the number of the physical layers or information about what component carriers are selected by the physical layers. 
     
     
         15 . A method in which a base station performs a call admission procedure in a carrier aggregation system which provides multiple component carriers, comprising:
 receiving a connection setup request message from user equipment;   determining whether each component carrier fulfills the requirements of the user equipment, and transmitting, to the user equipment, a connection setup admission message or a connection setup rejection message, including additional information, according to the results of the determination.   
     
     
         16 . The method of  claim 15 , wherein the additional information includes at least one piece of information about what component carriers are selectable by physical layers included in the user equipment, information about calculations for uplink timing alignment between the component carriers, or information about dedicated preambles of the respective component carriers. 
     
     
         17 . The method of  claim 15 , wherein when a component carrier selected by a primary physical layer which is one of a plurality of physical layers included in the user equipment does not fulfill the requirements of the user equipment, a connection setup rejection message including information about selectable component carriers is transmitted to the user equipment in order to allow the primary physical layer to select another component carrier. 
     
     
         18 . The method of  claim 15 , wherein when all component carriers selected by a plurality of physical layers included in the user equipment fulfill the requirements of the user equipment, a connection setup admission message including information about calculations for uplink timing alignment or information about dedicated preambles of the respective component carriers is transmitted to the user equipment. 
     
     
         19 . The method of  claim 15 , wherein when a component carrier selected by a primary component carrier which is one among a plurality of physical layers included in the user equipment fulfills the requirements of the user equipment but component carriers selected by the remaining physical layers except for the primary physical layer do not fulfill the requirements of the user equipment, a connection setup admission message including information about what component carriers are selectable by the remaining physical layers, information about calculations for uplink timing alignment between the component carriers selectable by the remaining physical layers and the component carrier selected by the primary physical layer, or information about dedicated preambles of the respective component carrier is transmitted to the user equipment. 
     
     
         20 . The method of  claim 15 , further comprising when additional allocation of a component carrier is needed after connection setup is completed, transmitting information about another component carrier to the user equipment.