Abstract:
A communication device for handling system information comprises a storage unit for storing instructions and a processing means coupled to the storage unit. The processing means is configured to execute the instructions stored in the storage unit. The instructions comprise receiving at least one legacy system information block (SIB) including at least one first configuration in a cell; receiving at least one enhanced coverage (EC) SIB including at least one second configuration in the cell; and applying the at least one second configuration instead of the at least one first configuration, when the communication device is a low complexity communication device or is configured to apply the at least one EC SIB instead of the at least one legacy SIB wherein the at least one first configuration and the at least one second configuration are transmitted for a same communication function.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/159,949, filed on May 11, 2015, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a communication device and a method used in a wireless communication system, and more particularly, to a communication device and a method of handling system information in a wireless communication system. 
     2. Description of the Prior Art 
     A long-term evolution (LTE) system includes a radio interface that provides high data rate, low latency, packet optimization, and improved system capacity and coverage, between communication between a user equipment (UE), and an evolved Node-B (eNB). 
     The UE may receive different system information blocks (SIBs) from a cell of the eNB when camping on the cell, wherein the SIBs may include different configurations, respectively. However, the configurations may be used for a same communication function. The UE does not know which of the configurations should be applied to the communication function, after the UE receives these different SIBs. Thus, how to handle system information transmitted by the cell is a problem to be solved. 
     SUMMARY OF THE INVENTION 
     The present invention therefore provides a communication device and a method for handling system information to solve the abovementioned problem. 
     A communication device for handling system information comprises a storage unit for storing instructions and a processing means coupled to the storage unit. The processing means is configured to execute the instructions stored in the storage unit. The instructions comprise receiving at least one legacy system information block (SIB) including at least one first configuration in a cell; receiving at least one enhanced coverage (EC) SIB including at least one second configuration in the cell; and applying the at least one second configuration instead of the at least one first configuration, when the communication device is a low complexity communication device or is configured to apply the at least one EC SIB instead of the at least one legacy SIB, wherein the at least one first configuration and the at least one second configuration are transmitted for a same communication function. 
     A communication device for handling system information comprises a storage unit for storing instructions and a processing means coupled to the storage unit. The processing means is configured to execute the instructions stored in the storage unit. The instructions comprise receiving at least one legacy SIB including at least one first configuration in a cell; receiving at least one EC SIB including at least one second configuration in the cell; and applying the at least one first configuration instead of the at least one second configuration, when the communication device is not a low complexity communication device, wherein the at least one first configuration and the at least one second configuration are transmitted for a same communication function. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a wireless communication system according to an example of the present invention. 
         FIG. 2  is a schematic diagram of a communication device according to an example of the present invention. 
         FIG. 3  is a flowchart of a process according to an example of the present invention. 
         FIG. 4  is a flowchart of a process according to an example of the present invention. 
         FIG. 5  is a flowchart of a process according to an example of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic diagram of a wireless communication system  10  according to an example of the present invention. The wireless communication system  10  is briefly composed of a network and a plurality of communication devices. In  FIG. 1 , the network and the communication devices are simply utilized for illustrating the structure of the wireless communication system  10 . Practically, the network may be a universal terrestrial radio access network (UTRAN) comprising at least one Node-B (NB) and/or a Radio Network Controller (RNC) in a universal mobile telecommunications system (UMTS). In one example, the network may be an evolved UTRAN (E-UTRAN) comprising at least one evolved NB (eNB) and/or at least one relay in a long term evolution (LTE) system, a LTE-Advanced (LTE-A) system or an evolution of the LTE-A system. In another example, the network may be a fifth generation (5G) network including at least one 5G base station (BS) which employs orthogonal frequency-division multiplexing (OFDM) and/or non-OFDM, and transmission time interval smaller than 1 millisecond (ms) for communication with the communication devices. In general, a base station (BS) may also be used to refer any of the NB, the RNC, the eNB and the 5G BS. 
     A communication device can be a user equipment (UE), a low cost device (e.g., machine type communication (MTC) device), a mobile phone, a laptop, a tablet computer, an electronic book, a portable computer system, a vehicle or aircraft. In addition, the network and the communication device can be seen as a transmitter or a receiver according to direction (i.e., transmission direction), e.g., for an uplink (UL), the communication device is the transmitter and the network is the receiver, and for a downlink (DL), the network is the transmitter and the communication device is the receiver. 
       FIG. 2  is a schematic diagram of a communication device  20  according to an example of the present invention. The communication device  20  may be a communication device or the network shown in  FIG. 1 , but is not limited herein. The communication device  20  may include a processing means  200  such as a microprocessor or Application Specific Integrated Circuit (ASIC), a storage unit  210  and a communication interfacing unit  220 . The storage unit  210  may be any data storage device that may store a program code  214 , accessed and executed by the processing means  200 . Examples of the storage unit  210  include but are not limited to a subscriber identity module (SIM), read-only memory (ROM), flash memory, random-access memory (RAM), hard disk, optical data storage device, non-volatile storage unit, non-transitory computer-readable medium (e.g., tangible media), etc. The communication interfacing unit  220  is preferably a transceiver and is used to transmit and receive signals (e.g., data, signals, messages and/or packets) according to processing results of the processing means  200 . For simplicity, the UE is used to represent the communication device in  FIG. 1  in the following examples. 
       FIG. 3  is a flowchart of process  30  according to an example of the present invention. The process  30  may be utilized in a UE of  FIG. 1 , to handle system information. The process  30  includes the following steps: 
     Step  302 : Start. 
     Step  304 : Receive at least one legacy system information block (SIB) including at least one first configuration in a cell. 
     Step  306 : Receive at least one enhanced coverage (EC) SIB including at least one second configuration in the cell. 
     Step  308 : Apply the at least one second configuration instead of the at least one first configuration, when the UE is a low complexity UE or is configured to apply the at least one EC SIB instead of the at least one legacy SIB, wherein the at least one first configuration and the at least one second configuration are transmitted for a same communication function. 
     Step  310 : End. 
     According to the process  30 , the UE receives at least one legacy SIB (e.g., SIB type 1 (SIB1) and/or SIB type 2 (SIB2)) including at least one first configuration, in a cell from a network. The UE receives at least one EC SIB including at least one second configuration, in the cell from the network. Then, the UE applies the at least one second configuration instead of the at least one first configuration, when the UE is a low complexity UE or is configured to apply the at least one EC SIB instead of the at least one legacy SIB, wherein the at least one first and second configurations are transmitted by the network on the cell for a same communication function (or functionality). That is, the UE applies (e.g., uses) the at least one second configuration to the communication function, when the UE is the low complexity UE or is configured to apply the at least one EC SIB. 
     Realization of the present invention is not limited to the above description. The following examples may be applied to the process  30 . 
     In one example, the at least one first configuration may include at least one first cell barred information, and the at least one second configuration may include at least one second cell barred information. The UE determines that the cell is barred, when the at least one second cell barred information (e.g., cellBarred information element (IE)) indicates that the cell is barred irrespective of the at least one first cell barred information (e.g., cellBarred IE) indicates that the cell is barred or not. For example, the UE determines that the cell is barred, when the at least one first cell barred information indicates that the cell is not barred and the at least one second cell barred information indicates that the cell is barred. In one example, the UE determines that the cell is not barred, when the at least one second cell barred information indicates that the cell is not barred irrespective of that the at least one first cell barred information indicates that the cell is barred or not. 
     In one example, the at least one first configuration may include at least one first access barring configuration, and the at least one second configuration may include at least one second access barring configuration. In one example, the UE applies the at least one second access barring configuration by performing a barring check for a specific access according to the at least one second access barring configuration, wherein the at least one first access barring configuration does not configure a access barring for the specific access and the at least one second access barring configuration configures the access barring for the specific access. In one example, the UE applies the at least one second access barring configuration by stopping performing a barring check for a specific access according to the at least one second access barring configuration, wherein the at least one first access barring configuration configures a access barring for the specific access and the at least second access barring configuration does not configure the access barring for the specific access. 
     In one example, the at least one first configuration may include at least one first random access (RA) configuration, and the at least one second configuration may include at least one second RA configuration. In one example, the UE applies the at least one second RA configuration by performing a RA according to the at least one second RA configuration instead of the at least one first RA configuration. 
     In one example, the UE applies the at least one second configuration instead of the at least one first configuration, when determining the at least one legacy SIB as invalid. The UE may determine the at least one legacy SIB as invalid, when the UE does not receive the at least one legacy SIB in or after a first time period (e.g., a predetermined time period, or one or more first modification periods). For example, the UE receives the at least one legacy SIB in every first time period. After a while, the UE is not able to receive the at least one legacy SIB but is able to receive the at least one EC SIB. Then, the UE starts a first timer to count the first time period. The UE restarts or stops the first timer when the UE receives the at least one legacy SIB. The UE determines the at least one legacy SIB as invalid, when the first timer expires. In one example, the UE determines the at least one legacy SIB as invalid or configures itself to apply the at least one EC SIB, if signal strength measured by the UE is below a threshold. Otherwise, the UE configures itself to apply the at least one legacy SIB. 
       FIG. 4  is a flowchart of process  40  according to an example of the present invention. The process  40  may be utilized in a UE of  FIG. 1 , to handle system information. The process  40  and includes the following steps: 
     Step  402 : Start. 
     Step  404 : Receive at least one legacy SIB including at least one first configuration in a cell. 
     Step  406 : Receive at least one EC SIB including at least one second configuration in the cell. 
     Step  408 : Apply the at least one first configuration instead of the at least one second configuration, when the UE is not a low complexity UE, wherein the at least one first configuration and the at least one second configuration are transmitted for a same communication function. 
     Step  410 : End. 
     According to the process  40 , the UE receives at least one legacy SIB (e.g., SIB1 and/or SIB2) including at least one first configuration, in a cell from the network. The UE receives at least one EC SIB including at least one second configuration, in the cell from the network. Then, the UE applies the at least one first configuration instead of the at least one second configuration, when the UE is not a low complexity UE, and the at least one first and second configurations are transmitted by the network for a same communication function (or functionality). That is, the UE applies (e.g., uses) the at least one first configuration to the communication function, when the UE is not the low complexity UE. 
     Realization of the present invention is not limited to the above description. The following examples may be applied to the process  40 . 
     In one example, the at least one first configuration in the process  40  may include at least one first cell barred information, and the at least one second configuration may include at least one second cell barred information. The UE determines that the cell is barred, when the at least one first cell barred information (e.g., cellBarred IE) indicates that the cell is barred irrespective of the at least one second cell barred information (e.g., cellBarred IE) indicates that the cell is barred or not. For example, the UE determines that the cell is barred, when the at least one first cell barred information indicates that the cell is barred and the at least one second cell barred information indicates that the cell is not barred. In one example, the UE determines that the cell is not barred, when the at least one first cell barred information indicates that the cell is not barred irrespective of that the at least one second cell barred information indicates that the cell is barred or not. 
     In one example, the at least one first configuration may include at least one first access barring configuration, and the at least one second configuration may include at least one second access barring configuration. In one example, the UE applies the at least one first access barring configuration by performing a barring check for a specific access according to the at least one first access barring configuration, wherein the at least one second access barring configuration does not configure a access barring for the specific access and the at least one first access barring configuration configures the access barring for the specific access. In one example, the UE applies the at least one first access barring configuration by stopping performing a barring check for a specific access according to the at least one first access barring configuration, wherein the at least one second access barring configuration configures a access barring for the specific access and the at least first access barring configuration does not configure the access barring for the specific access. 
     In one example, the at least one first configuration may include at least one first RA configuration, and the at least one second configuration may include at least one second RA configuration. In one example, the UE applies the at least one first RA configuration by performing a RA according to the at least one first RA configuration instead of the at least one second RA configuration. 
     In one example, the UE applies the at least one first configuration instead of the at least one second configuration, when determining the at least one EC SIB as invalid. The UE may determine the at least one EC SIB as invalid, when the UE does not receive the at least one EC SIB in or after a second time period (e.g., a predetermined time period, or one or more second modification periods). For example, the UE receives the at least one EC SIB in second every time period. After a while, the UE is not able to receive the at least one EC SIB but is able to receive the at least one legacy SIB. Then, the UE starts a second timer to count the second time period. The UE restarts or stops the second timer when the UE receives the at least one EC SIB. The UE determines the at least one EC SIB as invalid, when the second timer expires. In one example, the UE determines the at least one EC SIB as invalid or configures itself to apply the at least one legacy SIB, if signal strength measured by the UE is above a threshold. 
       FIG. 5  is a flowchart of process  50  according to an example of the present invention. The process  50  may be utilized in a UE of  FIG. 1 , to handle system information. The process  50  includes the following steps: 
     Step  502 : Start. 
     Step  504 : Receive at least one legacy SIB including at least one first configuration in a cell. 
     Step  506 : Receive at least one EC SIB including at least one second configuration in the cell, wherein the at least one first configuration and the at least one second configuration are transmitted for a same communication function. 
     Step  508 : Apply the at least one first configuration instead of the at least one second configuration, if a capability of the UE is complied with the at least one first configuration. 
     Step  510 : Apply the at least one second configuration instead of the at least one first configuration, if the capability of the UE is not complied with the at least one first configuration. 
     Step  512 : End. 
     According to the process  50 , the UE receives at least one legacy SIB (e.g., SIB1 and/or SIB2) including at least one first configuration in a cell. The UE receives at least one EC SIB including at least one second configuration in the cell. The at least one first and second configurations are transmitted for a same communication function (or functionality). Then, the UE applies the at least one first configuration instead of the at least one second configuration, if a capability of the UE is complied with the at least one first configuration. The UE applies the at least one second configuration instead of the at least one first configuration, if the capability of the UE is not complied with the at least one first configuration. That is, the UE applies the at least one first or second configuration according to the capability of the UE. 
     Realization of the present invention is not limited to the above description. Examples below may be applied to the process  50 . 
     In one example, the at least one first configuration may include at least one first cell barred information, and the at least one second configuration may include at least one second cell barred information. In one example, the at least one first configuration may include at least one first access barring configuration, and the at least one second configuration may include at least one second access barring configuration. In one example, the at least one first configuration may include at least one first RA configuration, and the at least one second configuration may include at least one second RA configuration. In one example, the at least one first configuration may include at least one first common radio resource configuration, and the at least one second configuration may include at least one second common radio resource configuration. In one example, the UE applies the at least one first configuration, if the UE is not a low complexity UE (e.g., a bandwidth reduced low complexity UE) and is not configured to apply at least one EC SIB. The UE may configure itself not to apply the at least one EC SIB, if a signal strength measured by the UE is above a threshold. In one example, the UE applies the at least one second configuration of the at least one EC SIB, if the UE is the low complexity UE (e.g., a bandwidth reduced low complexity UE), or is configured to apply at least one EC SIB. The UE may configure itself to apply the at least one EC SIB, if the signal strength measured by the UE is below a threshold. 
     Examples below may be applied to the processes above. The network may transmit legacy and EC SIBs on different channels. The first and second configurations may include a same parameter (e.g. field or IE) or different parameters, and the network may configure different values for the same parameter. The specific access may include an emergency, a mobile originating (MO) signaling, a MO data, a circuit-switched fallback (CSFB), a Multi Media Telephony (MMTEL) voice, or a MMTEL video. The at least one first RA configuration may include a PRACH-Config and a RACH-ConfigCommon IEs for transmission of a preamble, and the at least one second RA configuration may indicate a preamble and/or a resource (e.g., a frequency resource and/or a time resource) for transmission of repetitions of a preamble. The threshold may be predetermined or configured by the network. 
     Those skilled in the art should readily make combinations, modifications and/or alterations on the abovementioned description and examples. Any of the above mentioned processes may be compiled into the program code  214 . The abovementioned description, steps and/or processes including suggested steps can be realized by means that could be hardware, software, firmware, an electronic system, or combination thereof. An example of the means may be the communication device  20 . 
     To sum up, the present invention provides a device and a method for handling system information. Thus, the UE is able to receive and determine to apply which of one or more configurations received in different SIBs under one or more different conditions. As a result, the problem of which configuration should be applied to the same communication function is solved, when the UE receives the configurations for the same communication function. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.