Abstract:
A method for handling Secondary Cell (SCell) reactivation by a mobile communication device supporting a Carrier Aggregation (CA) technique is provided. The method includes the following steps: receiving at least one Media Access Control (MAC) Control Element (CE) indicating activation of an already activated SCell with configured uplink from a service network, comparing an accumulated number of the at least one MAC CE with a predetermined number, and ignoring the MAC CE for the already activated SCell with configured uplink in response to the accumulated number of the at least one MAC CE being greater than or equal to the predetermined number.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application claims the benefit of U.S. Provisional Application No. 61/442,459, filed on Feb. 14, 2011, the entirety of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention generally relates to the handling of Secondary Cell (SCell) reactivation, and more particularly, to apparatuses and methods for handling reactivation of an activated SCell with configured uplink, so as to avoid unnecessary triggering of the Power Headroom Reporting (PHR) procedure and to avoid resetting associated timers. 
     2. Description of the Related Art 
     In order to meet user demand for higher data rates in wireless communications, support for wider transmission bandwidths is required. A so-called Carrier Aggregation (CA) technique has been proposed to allow expansion of effective bandwidths delivered to a User Equipment (UE) through concurrent utilization of radio resources across multiple carriers. The CA technique is most useful when it is difficult to derive a contiguous and extra wide bandwidth. With the CA technique, more than 2 frequency bands may be aggregated to form a larger transmission/receive bandwidth. Each of the aggregated frequency channels is generally referred to as a Component Carrier (CC), which may be taken as a component of the aggregated bandwidth. 
     Taking the Long Term Evolution (LTE) technology in compliance with release 10 of the 3rd Generation Partnership Project (3GPP) technical specifications as an example, a UE may have one Primary CC (also referred to as PCell) and up to 4 Secondary CCs (also referred to as SCells), and each of the SCells needs to be configured and activated before it may be used for data transmission or reception. An LIE system may first transmit a Radio Resource Control (RRC) message to configure the SCell(s) for the UE, and then activate the SCell(s) by dedicated signaling, such as an Activation/Deactivation Medium Access Control (MAC) Control Element (CE). Later, if a smaller transmission bandwidth is required instead, the LIE system may transmit another Activation/Deactivation MAC CE to the UE to deactivate one of the activated SCell(s). In addition, a deactivation timer may be maintained both in the network side and the UE to count a predetermined time period when the corresponding activated SCell may stay activated. When the deactivation timer expires, the LTE system and the UE may deactivate the corresponding SCell to save power consumed for monitoring the physical downlink shared channel (PDSCH) and physical downlink control channel (PDCCH) corresponding to the deactivated SCell. 
     Meanwhile, in a mobile communication system supporting the CA technique, how to efficiently distribute/allocate uplink transmission resources between multiple UEs is always a critical issue from the viewpoint of the network side. For better radio resource management, the Power Headroom Reporting (PHR) procedure has been introduced for enabling the UEs to provide specific power status information to the network side. Specifically, the report includes information about the difference between the nominal UE maximum transmit power and the estimated power for UpLink-Shared Channel (UL-SCH) transmission per activated SCell and also information about the difference between the nominal UE maximum power and the estimated power for UL-SCH and PUCCH transmission on the PCell. The reported information is especially important for the network side when allocating the transmission format (bandwidth and modulation and coding scheme) to different UEs. The network entity (eNB) can use the reported information to determine how much more uplink bandwidth per subframe a UE is capable of using, so as to avoid allocating uplink transmission resources to UEs which are unable to use them. Thus, the Signal to Interference-plus-Noise Ratio (SINR) may be decreased and the system capacity may be improved. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect of the invention, a method for handling SCell reactivation by a mobile communication device supporting a CA technique is provided. The method comprises the steps of: receiving at least one MAC CE indicating activation of an already activated SCell with configured uplink from a service network; comparing an accumulated number of the at least one MAC CE with a predetermined number; and ignoring the MAC CE for the already activated SCell with configured uplink in response to the accumulated number of the at least one MAC CE being greater than or equal to the predetermined number. 
     In another aspect of the invention, a method for handling SCell reactivation by a mobile communication device supporting a CA technique is provided. The method comprises the steps of: receiving a MAC CE indicating activation of an already activated SCell with configured uplink from a service network; determining whether the MAC CE also indicates activation of a deactivated SCell; and not restarting a prohibition timer for a PHR procedure in response to the MAC CE not indicating activation of the deactivated SCell. 
     In yet another aspect of the invention, a method for handling SCell reactivation by a mobile communication device supporting a CA technique is provided. The method comprises the steps of: receiving a MAC CE from a service network; determining whether the MAC CE indicates activation of an already activated SCell with configured uplink; and not restarting a deactivation timer associated with the already activated SCell with configured uplink in response to the MAC CE indicating activation of the already activated SCell with configured uplink. 
     Other aspects and features of the invention will become apparent to those with ordinary skill in the art upon review of the following descriptions of specific embodiments of the mobile communication devices and the methods for handling SCell reactivation. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is a block diagram illustrating a mobile communication environment according to an embodiment of the invention; 
         FIGS. 2A and 2B  show a message sequence chart illustrating the handling of the SCell reactivation according to an embodiment of the invention; 
         FIGS. 3A and 3B  show a message sequence chart illustrating the handling of the SCell reactivation according to another embodiment of the invention; 
         FIGS. 4A and 4B  show a message sequence chart illustrating the handling of the SCell reactivation according to yet another embodiment of the invention; 
         FIGS. 5A and 5B  show a message sequence chart illustrating the handling of the SCell reactivation according to still another embodiment of the invention; 
         FIG. 6  is a flow chart illustrating a method for handling SCell reactivation according to an embodiment of the invention; 
         FIG. 7  is a flow chart illustrating a method for handling SCell reactivation according to another embodiment of the invention; and 
         FIG. 8  is a flow chart illustrating a method for handling SCell reactivation according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The 3GPP technical specifications are used to teach the spirit of the invention, and the invention is not limited thereto. 
     According to release 10 of the 3GPP technical specifications, the PHR procedure will be triggered for several events: 1) when the prohibitPHR-Timer expires or has expired and the path loss has changed more than dl-PathlossChange dB for at least one activated SCell which is used as a pathloss reference since the last transmission of a PHR when the UE has UL resources for a new transmission; 2) when the periodicPHR-Timer expires; 3) upon configuration or reconfiguration of the power headroom reporting functionality by the upper layers, which is not used to disable the function; and 4) upon activation of an SCell with configured uplink. It is noted that, due to the format design of the Activation/Deactivation MAC CE, the network side will inevitably reactivate the already activated SCell(s) if it wishes to deactivate a certain SCell or activate a deactivated SCell among a plurality of activated SCells. When receiving such an Activation/Deactivation MAC CE, the UE will accordingly restart the deactivation timer (i.e., the sCellDeactivationTimer) for each reactivated SCell, which would result in the unnecessary prolonging of the activation period for each reactivated SCell. Also, the PHR procedure will be triggered every time when the UE receives such an Activation/Deactivation MAC CE to activate an SCell with configured uplink (referring to the PHR trigger event 4), and the PHR prohibition timer (i.e., the prohibitPHR-Timer) will be started. Thus, impact to the UE performance may be caused, such as unnecessary power consumption due to the frequent triggering of the PHR trigger event 4, and inappropriate prevention of other PHR trigger events (referring to the PHR trigger events 1 to 3) due to the PHR prohibition timer being frequently restarted by the PHR trigger event 4. 
     In order to solve the aforementioned problems, the invention proposes apparatuses and methods for handling SCell reactivation with limited triggering of the PHR procedure and limited extension of the activation period for each reactivated SCell.  FIG. 1  is a block diagram illustrating a mobile communication environment according to an embodiment of the invention. In the mobile communication environment  100 , the mobile communication device  110  is wirelessly connected to the service network  120  for obtaining wireless services. The service network  120  may comprise an access network  121  and a core network  122 , wherein the access network  121  may be an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) in the LTE/LTE-Advanced technology, and the core network  122  may be an Evolved Packet Core (EPC) in the LTE/LTE-Advanced technology. The mobile communication device  110  comprises a wireless module  111  for performing the functionality of wireless transmissions and receptions to and from the service network  120 , and a controller module  112  for controlling the operation of the wireless module  111  and other functional components, such as a display unit and/or keypad serving as the MMI (man-machine interface), a storage unit storing the program codes of the applications or communication protocols of the LTE/LTE-Advanced technology, or others. To further clarify, the wireless module  111  may be a radio frequency (RF) unit, and the controller module  112  may be a general-purpose processor or a micro-control unit (MCU) of a baseband unit. The baseband unit may contain multiple hardware devices to perform baseband signal processing, including analog to digital conversion (ADC)/digital to analog conversion (DAC), gain adjusting, modulation/demodulation, encoding/decoding, and so on. The RF unit may receive RF wireless signals, convert the received RF wireless signals to baseband signals, which are processed by the baseband unit, or receive baseband signals from the baseband unit and convert the received baseband signals to RF wireless signals, which are later transmitted. The RF unit may also contain multiple hardware devices to perform radio frequency conversion. For example, the RF unit may comprise a mixer to multiply the baseband signals with a carrier oscillated in the radio frequency of the mobile communication system, wherein the radio frequency may be 900 MHz, 2100 MHz, or 2.6 GHz utilized in the LTE/LTE-Advanced systems, or others depending on the Radio Access Technology (RAT) in use. 
     To be more specific, the controller module  112  controls the wireless module  111  for handling SCell reactivation.  FIGS. 2A and 2B  show a message sequence chart illustrating the handling of the SCell reactivation according to an embodiment of the invention. In this embodiment, one CC is configured as the PCell and two CCs are configured as the SCells with uplink (denoted as SCell#1 and SCell#2) for the wireless communications device  110 . Note that the PCell is always activated, while SCell#1 and SCell#2 are initially deactivated. When the service network  120  detects that a larger transmission bandwidth is required for the mobile communication device  110 , it transmits an Activation/Deactivation MAC CE indicating activation of an SCell with configured uplink, say SCell#2, to the mobile communication device  110  (step S 205 ). When receiving the Activation/Deactivation MAC CE, the controller module  112  activates SCell#2 and starts the deactivation timer associated with SCell#2 (step S 210 ). Meanwhile, the controller module  112  also triggers the PHR procedure and starts the prohibition timer for the PHR procedure (i.e., the PHR prohibition timer) (step S 215 ). During the running period of the PHR prohibition timer, the mobile communication device  110  is forbidden to perform the PHR procedure, so as to avoid frequent triggering of the PHR procedure. Subsequently, the service network  120  detects that a larger transmission bandwidth is again required for the mobile communication device  110 . Since the format design of the Activation/Deactivation MAC CE only provides control of the SCell with either activation or deactivation, the service network  120  has no choice but to transmit another Activation/Deactivation MAC CE to the mobile communication device  110 , which indicates activation of another SCell with configured uplink, say SCell#1, and also indicates activation of the already activated SCell#2 to keep SCell#2 activated (step S 220 ). Due to the fact that the second Activation/Deactivation MAC CE is only used for activation of the originally deactivated SCell#1 and is irrelevant to SCell#2, the controller module  112  ignores the Activation/Deactivation MAC CE for SCell#2 (step S 225 ). In other words, the deactivation timer associated with SCell#2 is not restarted. 
     The controller module  112  continues to handle the Activation/Deactivation MAC CE for SCell#1. Specifically, the controller module  112  activates SCell#1 and starts the deactivation timer for SCell#1 (step S 230 ). In response to the activation of SCell#1, the controller module  112  triggers the PHR procedure and starts the prohibition timer for the PHR procedure (step S 235 ). Next, when the service network  120  detects that a smaller transmission bandwidth is required for the mobile communication device  110 , it transmits an Activation/Deactivation MAC CE to the mobile communication device  110 , which indicates deactivation of SCell#1 and activation of the already activated SCell#2 to keep SCell#2 activated (step S 240 ). Due to the fact that the Activation/Deactivation MAC CE is used for deactivation of SCell#1 only and is irrelevant to SCell#2, the controller module  112  ignores the Activation/Deactivation MAC CE for SCell#2 (step S 245 ). In other words, the deactivation timer associated with SCell#2 is not restarted. After that, the controller module  112  continues to handle the Activation/Deactivation MAC CE for SCell#1 by deactivating SCell#1 and stopping the deactivation timer associated with SCell#1 (step S 250 ). Note that, the controller module  112  ignores the Activation/Deactivation MAC CE for the already activated SCell, so that unnecessary prolonging of the activation period of the already activated SCell may be avoided and the PHR procedure triggered by an Activation/Deactivation MAC CE indicating activation of an already activated SCell does not exclude other PHR trigger events (especially the PHR trigger events that are useful to the UE scheduler). 
       FIGS. 3A and 3B  show a message sequence chart illustrating the handling of the SCell reactivation according to another embodiment of the invention. Similar to  FIGS. 2A and 2B , one CC is configured as the PCell and two CCs are configured as the SCells with uplink (denoted as SCell#1 and SCell#2) for the wireless communications device  110 , and the PCell is always activated while SCell#1 and SCell#2 are initially deactivated. When the service network  120  detects that a larger transmission bandwidth is required for the mobile communication device  110 , it transmits an Activation/Deactivation MAC CE indicating activation of an SCell with configured uplink, say SCell#2, to the mobile communication device  110  (step S 305 ). When receiving the Activation/Deactivation MAC CE, the controller module  112  activates SCell#2 and starts the deactivation timer associated with SCell#2 (step S 310 ). Meanwhile, the controller module  112  also triggers the PHR procedure and starts the prohibition timer for the PHR procedure (step S 315 ). During the running period of the PHR prohibition timer, the mobile communication device  110  is forbidden to perform the PHR procedure, so as to avoid frequent triggering of the PHR procedure. Subsequently, the service network  120  detects that a larger transmission bandwidth is again required for the mobile communication device  110 . Since the format design of the Activation/Deactivation MAC CE only provides control of the SCell with either activation or deactivation, the service network  120  has no choice but to transmit another Activation/Deactivation MAC CE to the mobile communication device  110 , which indicates activation of another SCell with configured uplink, say SCell#1, and also indicates activation of the already activated SCell#2 to keep SCell#2 activated (step S 320 ). In this embodiment, the controller module  112  only ignores the Activation/Deactivation MAC CE for SCell#2 when the accumulated number of the Activation/Deactivation MAC CE indicating activation of an already activated SCell is greater than or equal to a predetermined number. The predetermined number may be any integer greater than or equal to 1, but preferably no more than 3. In this embodiment, the predetermined number is set to 2, but the invention is not limited thereto. Since this Activation/Deactivation MAC CE is the first one indicating activation of an already activated SCell, the controller module  112  does not ignore the Activation/Deactivation MAC CE for SCell#2. That is, the controller module  112  restarts the deactivation timer associated with SCell#2 (step S 325 ). 
     The controller module  112  continues to handle the Activation/Deactivation MAC CE for SCell#1. Specifically, the controller module  112  activates SCell#1 and starts the deactivation timer associated with SCell#1 (step S 330 ). In response to the activation of SCell#1 and the reactivation of SCell#2, the controller module  112  triggers the PHR procedure and starts the prohibition timer for the PHR procedure (step S 335 ). Next, when the service network  120  detects that a smaller transmission bandwidth is required for the mobile communication device  110 , it transmits an Activation/Deactivation MAC CE to the mobile communication device  110 , which indicates deactivation of SCell#1 and activation of the already activated SCell#2 to keep SCell#2 activated (step S 340 ). Due to the fact that the accumulated number of the Activation/Deactivation MAC CE indicating activation of an already activated SCell is equal to the predetermined number of 2, the controller module  112  ignores the Activation/Deactivation MAC CE for SCell#2, which re-activates SCell#2 (step S 345 ). In other words, the deactivation timer associated with SCell#2 is not restarted. After that, the controller module  112  continues to handle the Activation/Deactivation MAC CE for SCell#1 by deactivating SCell#1 and stopping the deactivation timer associated with SCell#1 (step S 350 ). Note that, the controller module  112  ignores the Activation/Deactivation MAC CE for the already activated SCell when the accumulated number of the Activation/Deactivation MAC CE indicating activation of an already activated SCell is greater than or equal to a predetermined number, so that unnecessary prolonging of the activation period of the already activated SCell may be subject to control and the PHR procedure triggered by an Activation/Deactivation MAC CE indicating activation of an already activated SCell does not always exclude other PHR trigger events through the PHR prohibition timer running (especially the PHR trigger events that are useful to the UE scheduler). 
       FIGS. 4A and 4B  show a message sequence chart illustrating the handling of the SCell reactivation according to yet another embodiment of the invention. Similar to  FIGS. 2A and 2B , one CC is configured as the PCell and two CCs are configured as the SCells with uplink (denoted as SCell#1 and SCell#2) for the wireless communications device  110 , and the PCell is always activated while SCell#1 and SCell#2 are initially deactivated. When the service network  120  detects that a larger transmission bandwidth is required for the mobile communication device  110 , it transmits an Activation/Deactivation MAC CE indicating activation of an SCell with configured uplink, say SCell#2, to the mobile communication device  110  (step S 405 ). When receiving the Activation/Deactivation MAC CE, the controller module  112  activates SCell#2 and starts the deactivation timer associated with SCell#2 (step S 410 ). Meanwhile, the controller module  112  also triggers the PHR procedure and starts the prohibition timer for the PHR procedure (step S 415 ). During the running period of the PHR prohibition timer, the mobile communication device  110  is forbidden to perform the PHR procedure, so as to avoid frequent triggering of the PHR procedure. Subsequently, the service network  120  detects that a larger transmission bandwidth is again required for the mobile communication device  110 . Since the format design of the Activation/Deactivation MAC CE only provides control of the SCell with either activation or deactivation, the service network  120  has no choice but to transmit another Activation/Deactivation MAC CE to the mobile communication device  110 , which indicates activation of another SCell with configured uplink, say SCell#1, and also indicates activation of the already activated SCell#2 to keep SCell#2 activated (step S 420 ). Note that, in this embodiment, the controller module  112  does not reset the prohibition timer for the PHR procedure, unless the Activation/Deactivation MAC CE also activates another deactivated SCell. In response to the Activation/Deactivation MAC CE indicating activation of the already activated SCell#2, the controller module  112  restarts the deactivation timer associated with SCell#2 (step S 425 ). In addition, due to the fact that the second Activation/Deactivation MAC CE is used for activation of the originally deactivated SCell#1, the controller module  112  activates SCell#1 and starts the deactivation timer associated with SCell#1 (step S 430 ), and then triggers the PHR procedure and starts the prohibition timer for the PHR procedure (step S 435 ). Next, when the service network  120  detects that a smaller transmission bandwidth is required for the mobile communication device  110 , it transmits an Activation/Deactivation MAC CE to the mobile communication device  110 , which indicates deactivation of SCell#1 and activation of the already activated SCell#2 to keep SCell#2 activated (step S 440 ). In response to the Activation/Deactivation MAC CE indicating activation of the already activated SCell#2, the controller module  112  restarts the deactivation timer associated with SCell#2 (step S 445 ). Due to the fact that the Activation/Deactivation MAC CE is used for deactivation of SCell#1 only and is irrelevant to SCell#2, the controller module  112  does not trigger the PHR procedure and does not start the prohibition timer for the PHR procedure (step S 450 ), so that the PHR procedure triggered by an Activation/Deactivation MAC CE indicating activation of an already activated SCell does not exclude other PHR trigger events through the PHR prohibition timer running (especially the PHR trigger events that are useful to the UE scheduler). After that, the controller module  112  continues to handle the Activation/Deactivation MAC CE for SCell#1 by deactivating SCell#1 and stopping the deactivation timer associated with SCell#1 (step S 455 ). 
       FIGS. 5A and 5B  show a message sequence chart illustrating the handling of the SCell reactivation according to still another embodiment of the invention. Similar to  FIGS. 2A and 2B , one CC is configured as the PCell and two CCs are configured as the SCells with uplink (denoted as SCell#1 and SCell#2) for the wireless communications device  110 , and the PCell is always activated while SCell#1 and SCell#2 are initially deactivated. When the service network  120  detects that a larger transmission bandwidth is required for the mobile communication device  110 , it transmits an Activation/Deactivation MAC CE indicating activation of an SCell with configured uplink, say SCell#2, to the mobile communication device  110  (step S 505 ). When receiving the Activation/Deactivation MAC CE, the controller module  112  activates SCell#2 and starts the deactivation timer associated with SCell#2 (step S 510 ). Meanwhile, the controller module  112  also triggers the PHR procedure and starts the prohibition timer for the PHR procedure (step S 515 ). During the running period of the PHR prohibition timer, the mobile communication device  110  is forbidden to perform the PHR procedure, so as to avoid frequent triggering of the PHR procedure. Subsequently, the service network  120  detects that a larger transmission bandwidth is again required for the mobile communication device  110 . Since the format design of the Activation/Deactivation MAC CE only provides control of the SCell with either activation or deactivation, the service network  120  has no choice but to transmit another Activation/Deactivation MAC CE to the mobile communication device  110 , which indicates activation of another SCell with configured uplink, say SCell#1, and also indicates activation of the already activated SCell#2 to keep SCell#2 activated (step S 520 ). In response to the Activation/Deactivation MAC CE indicating activation of the already activated SCell#2, the controller module  112  does not restart the deactivation timer associated with SCell#2 (step S 525 ), so that unnecessary prolonging of the activation period of SCell#2 may be avoided. In addition, due to the fact that the second Activation/Deactivation MAC CE is used for activation of the originally deactivated SCell#1, the controller module  112  activates SCell#1 and starts the deactivation timer associated with SCell#1 (step S 530 ), and then triggers the PHR procedure and starts the prohibition timer for the PHR procedure (step S 535 ). Next, when the service network  120  detects that a smaller transmission bandwidth is required for the mobile communication device  110 , it transmits an Activation/Deactivation MAC CE to the mobile communication device  110 , which indicates deactivation of SCell#2 and activation of the already activated SCell#2 to keep SCell#2 activated (step S 540 ). In response to the Activation/Deactivation MAC CE indicating activation of the already activated SCell#2, the controller module  112  does not restart the deactivation timer associated with SCell#2 (step S 545 ), and then triggers the PHR procedure and starts the prohibition timer for the PHR procedure (step S 550 ). After that, the controller module  112  continues to handle the Activation/Deactivation MAC CE for SCell#1 by deactivating SCell#1 and stopping the deactivation timer associated with SCell#1 (step S 555 ). 
       FIG. 6  is a flow chart illustrating a method for handling SCell reactivation according to an embodiment of the invention. The method for handling SCell reactivation may be applied to any mobile communication device supporting the CA technique and the LTE/LTE-Advanced technology, such as the mobile communication device  110  in  FIG. 1 . Specifically, the mobile communication device is wireless connected to a service network for obtaining wireless services, wherein the service network also supports the CA technique. In this embodiment, there are one PCell and a plurality of SCells configured for the mobile communication device, and at least one of the SCells is activated. To begin the method, the mobile communication device receives at least one MAC CE indicating activation of an already activated SCell with configured uplink from the service network (step S 610 ). The MAC CE may be an Activation/Deactivation MAC CE. Subsequently, the mobile communication device compares the accumulated number of the at least one MAC CE with a predetermined number (step S 620 ). Next, the mobile communication device ignores the MAC CE for the already activated SCell with configured uplink in response to the accumulated number of the at least one MAC CE being greater than or equal to the predetermined number (step S 630 ). Note that, the predetermined number may be any integer greater than or equal to 1, but preferably no more than 3. For example, if the predetermined number is set to 1, the mobile communication device may ignore each of the at least one MAC CE for the already activated SCell with configured uplink. If the predetermined number is set to 2, the mobile communication device may tolerate one reactivation of the already activated SCell, i.e., the mobile communication device may handle the MAC CE for the already activated SCell with configured uplink by triggering the PHR procedure, starting the prohibition timer for the PHR procedure, and restarting the deactivation associated with the already activated SCell, for only once, and then ignore any subsequent MAC CE indicating activation of an already activated SCell with configured uplink, for the already activated SCell with configured uplink. Thus, unnecessary prolonging of the activation period of the already activated SCell may be subject to control, and the PHR procedure triggered by an MAC CE indicating activation of an already activated SCell with configured uplink does not always exclude other PHR trigger events (especially the PHR trigger events that are useful to the UE scheduler). 
       FIG. 7  is a flow chart illustrating a method for handling SCell reactivation according to another embodiment of the invention. Similar to  FIG. 6 , the method for handling SCell reactivation may be applied to any mobile communication device supporting the CA technique and the LTE/LTE-Advanced technology, such as the mobile communication device  110  in  FIG. 1 . Specifically, the mobile communication device is wireless connected to a service network for obtaining wireless services, wherein the service network also supports the CA technique. In this embodiment, there are one PCell and a plurality of SCells configured for the mobile communication device, and at least one of the SCells is activated. To begin the method, the mobile communication device receives a MAC CE indicating activation of an already activated SCell with configured uplink from the service network (step S 710 ). The MAC CE may be an Activation/Deactivation MAC CE. Subsequently, the mobile communication device determines whether the MAC CE also indicates activation of a deactivated SCell (step S 720 ). Next, the mobile communication device does not start a prohibition timer for a PHR procedure in response to the MAC CE not indicating activation of a deactivated SCell (step S 730 ). Note that, the mobile communication device does not start the prohibition timer for the PHR procedure, unless the MAC CE also indicates activation of another deactivated SCell. In other words, the mobile communication device starts the prohibition timer for the PHR procedure if the MAC CE only indicates activation of an already activated SCell with configured uplink. Thus, the PHR procedure triggered by a MAC CE indicating activation of an already activated SCell with configured uplink does not exclude other PHR trigger events through the PHR prohibition timer running (especially the PHR trigger events that are useful to the UE scheduler). 
       FIG. 8  is a flow chart illustrating a method for handling SCell reactivation according to another embodiment of the invention. Similar to  FIG. 6 , the method for handling SCell reactivation may be applied to any mobile communication device supporting the CA technique and the LTE/LTE-Advanced technology, such as the mobile communication device  110  in  FIG. 1 . Specifically, the mobile communication device is wireless connected to a service network for obtaining wireless services, wherein the service network also supports the CA technique. In this embodiment, there are one PCell and a plurality of SCells configured for the mobile communication device, and at least one of the SCells is activated. To begin the method, the mobile communication device receives a MAC CE from the service network (step S 810 ). Subsequently, the mobile communication device determines whether the MAC CE indicates activation of an already activated SCell with configured uplink (step S 820 ). Next, the mobile communication device does not restart a deactivation timer associated with the already activated SCell with configured uplink in response to the MAC CE indicating activation of an already activated SCell with configured uplink (step S 830 ). Since the deactivation timer associated with an already activated SCell does not get restarted when a MAC CE indicates activation of the already activated SCell with configured uplink is received, unnecessary prolonging of the activation period of the already activated SCell may be avoided. 
     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. Those who are skilled in this technology can still make various alterations and modifications without departing from the scope and spirit of this invention. For example, the method for handling SCell reactivation may also be applied to mobile communication devices in compliance with any evolutionary technology of the LTE/LTE-Advanced technology. Therefore, the scope of the invention shall be defined and protected by the following claims and their equivalents.