Abstract:
A communication device of handling a wireless local area network (WLAN) measurement configuration comprises instructions of establishing a connection to a base station (BS) of a cellular network; receiving the WLAN measurement configuration on the connection from the BS; performing WLAN measurement on a WLAN according to the WLAN measurement configuration; transmitting a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration; receiving a cellular-WLAN aggregation (CWA) configuration on the connection from the BS; communicating a plurality of packets with the WLAN according to the CWA configuration; keeping the WLAN measurement configuration, when detecting a connection failure on the WLAN; and releasing the WLAN measurement configuration, when detecting a connection failure on the cellular network.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/200,132, filed on Aug. 3, 2015, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    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 method of handling a wireless local area network measurement configuration in a wireless communication system. 
         [0004]    2. Description of the Prior Art 
         [0005]    Long term evolution (LTE)-wireless local area network (WLAN) aggregation is used for increasing data rate. An evolved Node-B (eNB) configures a WLAN measurement configuration to a user equipment (UE) for the LTE-WLAN aggregation. The UE transmits a WLAN measurement report to the eNB according to the WLAN measurement configuration. The eNB configures the UE to perform the LTE-WLAN aggregation according to the WLAN measurement report. However, it is unknown how the UE handles the WLAN measurement configuration, when detecting a LTE connection failure or a WLAN connection failure. 
         [0006]    Thus, how to handle the WLAN measurement configuration is an important problem to be solved. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention therefore provides a method and related communication device for handling a wireless local area network measurement configuration to solve the abovementioned problem. 
         [0008]    A communication device of handling a wireless local area network (WLAN) measurement configuration 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 establishing a connection to a base station (BS) of a cellular network; receiving the WLAN measurement configuration on the connection from the BS; performing WLAN measurement on a WLAN according to the WLAN measurement configuration; transmitting a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration; receiving a cellular-WLAN aggregation (CWA) configuration on the connection from the BS; communicating a plurality of packets with the WLAN according to the CWA configuration; keeping the WLAN measurement configuration, when detecting a connection failure on the WLAN; and releasing the WLAN measurement configuration, when detecting a connection failure on the cellular network. 
         [0009]    A communication device of handling a wireless local area network (WLAN) measurement configuration 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 establishing a connection to a base station (BS) of a cellular network; receiving the WLAN measurement configuration on the connection from the BS; performing WLAN measurement on a WLAN according to the WLAN measurement configuration; transmitting a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration; receiving a cellular-WLAN aggregation (CWA) configuration on the connection from the BS; communicating a plurality of packets with the WLAN according to the CWA configuration; releasing the WLAN measurement configuration, when detecting a connection failure on the WLAN; and releasing the WLAN measurement configuration, when detecting a connection failure on the cellular network. 
         [0010]    A communication device of handling a wireless local area network (WLAN) measurement configuration 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 establishing a connection to a base station (BS) of a cellular network; receiving the WLAN measurement configuration on the connection from the BS; performing WLAN measurement on a WLAN according to the WLAN measurement configuration; transmitting a first WLAN measurement result of the WLAN measurement to the BS on the connection according to the WLAN measurement configuration; receiving a cellular-WLAN aggregation (CWA) configuration on the connection from the BS; communicating a plurality of packets with the WLAN according to the CWA configuration; keeping the WLAN measurement configuration, when detecting a connection failure on the WLAN; and keeping the WLAN measurement configuration, when detecting a connection failure on the cellular network. 
         [0011]    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 
         [0012]      FIG. 1  is a schematic diagram of a wireless communication system according to an example of the present invention. 
           [0013]      FIG. 2  is a schematic diagram of a communication device according to an example of the present invention. 
           [0014]      FIG. 3  is a flowchart of a process according to an example of the present invention. 
           [0015]      FIG. 4  is a flowchart of a process according to an example of the present invention. 
           [0016]      FIG. 5  is a flowchart of a process according to an example of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      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 cellular network  100 , a wireless local area network (WLAN)  102  and a communication device  104 . Practically, the cellular network  100  may be an evolved UTRAN (E-UTRAN) comprising at least one evolved NB (eNB) and/or at least one relay. In another example, the cellular network  100  may be a fifth generation (5G) network including at least one 5G eNB which employs orthogonal frequency-division multiplexing (OFDM) and/or non-OFDM on a wider carrier frequency, and a transmission time interval (TTI) for communicating with the communication devices is smaller than 1 millisecond (ms). In general, a base station (BS) is used to refer any of the eNB and the 5G eNB. In one example, a WiFi standard operated by the WLAN may include 802.11ax, 802.11ad, 802.11ac, 802.11n, 802.11g, 802.11b and 802.11a operated in 2.4 GHz, 5 GHz or 60 GHz band. 
         [0018]    The communication device  104  can be a user equipment (UE), a mobile phone, a laptop, a tablet computer, an electronic book, a portable computer system, a vehicle or aircraft. In addition, the cellular network  100  and the communication device  104  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  104  is the transmitter and the cellular network  100  (or the WLAN  102 ) is the receiver, and for a downlink (DL), the cellular network  100  (or the WLAN  102 ) is the transmitter and the communication device  104  is the receiver. 
         [0019]      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 the communication device  104 , the cellular network  100  or the WLAN  102  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 , a communication interfacing unit  220  for long term evolution (LTE)/5G transmission/reception, and a communication interfacing unit  222  for WLAN (e.g., WiFi) transmission/reception. 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 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, messages and/or packets) according to processing results of the processing means  200 . 
         [0020]    In the following embodiments, a UE is used to represent the communication device  104  in  FIG. 1 . 
         [0021]      FIG. 3  is a flowchart of a process  30  according to an example of the present invention. The process  30  may be utilized in a UE, to handle a WLAN measurement configuration. The process  30  includes the following steps: 
         [0022]    Step  300 : Start. 
         [0023]    Step  302 : Establish a connection to a BS of a cellular network. 
         [0024]    Step  304 : Receive the WLAN measurement configuration on the connection from the BS. 
         [0025]    Step  306 : Perform WLAN measurement on a WLAN according to the WLAN measurement configuration. 
         [0026]    Step  308 : Transmit a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration. 
         [0027]    Step  310 : Receive a cellular-WLAN aggregation (CWA) configuration on the connection from the BS. 
         [0028]    Step  312 : Communicate a plurality of packets with the WLAN according to the CWA configuration. 
         [0029]    Step  314 : Keep the WLAN measurement configuration, when detecting a connection failure on the WLAN. 
         [0030]    Step  316 : Release the WLAN measurement configuration, when detecting a connection failure on the cellular network. 
         [0031]    Step  318 : End. 
         [0032]    According to the process  30 , the UE establishes a connection to a BS of a cellular network, and receives the WLAN measurement configuration on the connection from the BS. Then, the UE performs WLAN measurement on a WLAN according to the WLAN measurement configuration, and transmits a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration. Further, the UE receives a CWA configuration on the connection from the BS, and communicates a plurality of packets with the WLAN according to the CWA configuration. Further, the UE keeps the WLAN measurement configuration, when (e.g., in response to) detecting a connection failure on the WLAN (e.g., a WiFi connection is lost). The UE releases the WLAN measurement configuration, when (e.g., in response to) detecting a connection failure on the cellular network (e.g., an LTE radio link failure (RLF)). 
         [0033]    Realization of the process  30  is not limited to the above description. The following examples are used for illustrating the process  30 . 
         [0034]    In one example, the connection includes a radio link connecting the UE and a cell of the BS. In one example, the connection includes a radio resource control (RRC) connection with the BS and the UE establishes the connection by a RRC connection establishment procedure or a handover procedure. The connection may further have at least one radio bearer configured by the cellular network. The cellular network may be a LTE or 5G network. In one example, the WLAN measurement configuration includes at least one of an identifier of the WLAN, a channel number, band information (e.g. 2.4 GHz, 5 GHz or 60 GHz), a measurement or reporting metric, a measurement method and a reporting configuration. In one example, the UE searches or measures the WLAN periodically according to a period. The period is indicated by the measurement method, or determined by the UE if the WLAN measurement configuration does not include the measurement method. The band information indicates a frequency band of the WLAN and the channel number indicates a channel of the WLAN. In one example, the UE tries to detect the WLAN in the band indicated by the band information or on a carrier indicated by the channel number, if the WLAN measurement configuration includes the band information or the channel number. In another example, the UE tries to detect the WLAN on any carrier, if the WLAN measurement configuration neither includes the band information nor the channel number. If the UE visited the WLAN before, the UE may store a channel number or band information of the WLAN and try to detect the WLAN according to the stored channel number or band information. 
         [0035]    In one example, the UE transmits the first WLAN measurement result to the BS according to the reporting configuration. The reporting configuration includes a reporting event or a reporting period. In one example, the first WLAN measurement result indicates a signal strength or quality of the WLAN. The signal strength or quality is good or larger (e.g., stronger or better) than a threshold. Accordingly, the BS transmits the CWA configuration on the connection to the UE in response to the first WLAN measurement result. In one example, the UE transmits the plurality of packets to the WLAN or receives the plurality of packets from the WLAN, to perform the CWA. In another example, the UE transmits a second WLAN measurement result indicating a signal strength or quality of the WLAN when communicating with the WLAN for the CWA. 
         [0036]    In one example, a signal strength or quality of the WLAN becomes weak, when the UE is moving away from the WLAN. In another example, the UE is not able to receive a beacon of the WLAN suddenly due to fading. The UE detects the connection failure on the WLAN in the two examples according to at least one of following criteria or condition. In one example, the UE detects the connection failure on the WLAN, when the UE detects that a signal strength (e.g., of a beacon) or quality of the WLAN is less (e.g., weaker) than a threshold. In another example, the UE detects the connection failure on the WLAN, when the UE does not detect any beacon (e.g., a beacon of the WLAN). Thus, the UE suspends transmission to the WLAN. The UE may transmit a third WLAN measurement result indicating the signal strength or quality or indicating the connection failure on the WLAN on the connection to the BS, such that the BS may suspend transmission of a plurality of packets to the UE via the WLAN. According to the process  30 , the UE keeps the WLAN measurement configuration while connecting to the cellular network, when detecting the connection failure on the WLAN. Then, the UE may detect the WLAN again, after detecting the connection failure on the WLAN. Further, the UE transmits a fourth WLAN measurement result on the connection to the BS according to the WLAN measurement configuration, after (e.g., when) detecting the WLAN again. The fourth WLAN measurement result indicates the signal strength or quality of the WLAN which becomes good. Thus, the BS may resume transmission of a plurality of packets to the UE via the WLAN. 
         [0037]    In one example, the WLAN measurement configuration is included in a first RRC message (e.g. RRCConnectionReconfiguration), and the CWA configuration is included in a second RRC message. In one example, the second RRC message is an RRCConnectionReconfiguration message including the identifier of the WLAN for the CWA. 
         [0038]    In one example, the UE performs a connection recovery procedure (e.g. RRC connection reestablishment procedure) with the cellular network, after (e.g., when) detecting the connection failure on the cellular network (e.g., an LTE RLF). Further, the UE releases the WLAN measurement configuration in response to the connection failure on the cellular network or in response to the RRC connection reestablishment procedure. Accordingly, the UE does not transmit any WLAN measurement result to the BS according to the WLAN measurement configuration. In one example, the BS releases the WLAN measurement configuration in a context of the UE stored in the BS, in response to an RRCConnectionReestablishmentRequest message of the RRC connection reestablishment procedure received from the UE. 
         [0039]    In one example, the UE releases the WLAN measurement configuration, when selecting (e.g., connecting to) another WLAN not being configured by the BS for the CWA. More specifically, the UE selects (e.g., connect to) the said other WLAN having a different identifier from the identifier of the WLAN, during searching the WLAN after detecting the connection failure on the WLAN. Further, the UE indicates it connects to the said other WLAN to the BS. Accordingly, the BS releases the WLAN measurement configuration in the context of the UE, when receiving the indication. 
         [0040]    In one example, the WLAN measurement configuration includes a detecting configuration for detecting the WLAN. In one example, the detecting configuration includes a plurality of LTE/5G cell identities (e.g., physical cell identities (PCIs)) of (e.g., corresponding to) a plurality of LTE/5G cells. The UE determines to detect the WLAN, when the UE detects the plurality of LTE/5G cell identities. In one example, the detecting configuration further includes a LTE/5G carrier frequency of the plurality of LTE/5G cell identities. When the measurement configuration does not include the detecting configuration, the UE may have the plurality of LTE/5G cell identities if the UE detected the WLAN before. 
         [0041]      FIG. 4  is a flowchart of a process  40  according to an example of the present invention. The process  40  may be utilized in a UE, to handle a WLAN measurement configuration. The process  40  includes the following steps: 
         [0042]    Step  400 : Start. 
         [0043]    Step  402 : Establish a connection to a BS of a cellular network. 
         [0044]    Step  404 : Receive the WLAN measurement configuration on the connection from the BS. 
         [0045]    Step  406 : Perform WLAN measurement on a WLAN according to the WLAN measurement configuration. 
         [0046]    Step  408 : Transmit a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration. 
         [0047]    Step  410 : Receive a CWA configuration on the connection from the BS. 
         [0048]    Step  412 : Communicate a plurality of packets with the WLAN according to the CWA configuration. 
         [0049]    Step  414 : Release the WLAN measurement configuration, when detecting a connection failure on the WLAN. 
         [0050]    Step  416 : Release the WLAN measurement configuration, when detecting a connection failure on the cellular network. 
         [0051]    Step  418 : End. 
         [0052]    According to the process  40 , the UE establishes a connection to a BS of a cellular network, and receives the WLAN measurement configuration on the connection from the BS. Then, the UE performs WLAN measurement on a WLAN according to the WLAN measurement configuration, and transmits a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration. Further, the UE receives a CWA configuration on the connection from the BS, and communicate a plurality of packets with the WLAN according to the CWA configuration. Further, the UE releases the WLAN measurement configuration, when (e.g., in response to) detecting a connection failure on the WLAN (e.g., a WiFi connection is lost). The UE releases the WLAN measurement configuration, when (e.g., in response to) detecting a connection failure on the cellular network (e.g., an LTE RLF). 
         [0053]    Realization of the process  40  is not limited to the above description. The following examples are used for illustrating the process  40 . 
         [0054]    The Process  40  is similar to the process  30  except that the UE may release the WLAN measurement configuration, if the connection failure on the WLAN network occurs. Thus, the UE may not need to perform the WLAN measurement and the reporting, and a battery power of the UE is saved. 
         [0055]    In one example, the UE transmits an indication on the connection to the BS, when detecting the connection failure on the WLAN or when selecting another WLAN. Accordingly, the BS may release the WLAN measurement configuration in a context of the UE stored in the BS, when receiving the indication. Further, the BS may transmit another WLAN measurement configuration to the UE in response to the indication. The said other WLAN measurement configuration may include an identifier of the other WLAN for the UE to detect and measure the other WLAN. 
         [0056]      FIG. 5  is a flowchart of a process  50  according to an example of the present invention. The process  50  may be utilized in a UE, to handle a WLAN measurement configuration. The process  50  includes the following steps: 
         [0057]    Step  500 : Start. 
         [0058]    Step  502 : Establish a connection to a BS of a cellular network. 
         [0059]    Step  504 : Receive the WLAN measurement configuration on the connection from the BS. 
         [0060]    Step  506 : Perform WLAN measurement on a WLAN according to the WLAN measurement configuration. 
         [0061]    Step  508 : Transmit a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration. 
         [0062]    Step  510 : Receive a CWA configuration on the connection from the BS. 
         [0063]    Step  512 : Communicate a plurality of packets with the WLAN according to the CWA configuration. 
         [0064]    Step  514 : Keep the WLAN measurement configuration, when detecting a connection failure on the WLAN. 
         [0065]    Step  516 : Keep the WLAN measurement configuration, when detecting a connection failure on the cellular network. 
         [0066]    Step  518 : End. 
         [0067]    According to the process  50 , the UE establishes a connection to a BS of a cellular network, and receives the WLAN measurement configuration on the connection from the BS. Then, the UE performs WLAN measurement on a WLAN according to the WLAN measurement configuration, and transmits a first WLAN measurement result of the WLAN measurement on the connection to the BS according to the WLAN measurement configuration. Further, the UE receives a CWA configuration on the connection from the BS, and communicates a plurality of packets with the WLAN according to the CWA configuration. Further, the UE keeps the WLAN measurement configuration according to the WLAN measurement configuration, when (e.g., in response to) detecting a connection failure on the WLAN (e.g., a WiFi connection is lost). The UE keeps the WLAN measurement configuration, when (e.g., in response to) detecting a connection failure on the cellular network (e.g., an LTE RLF). 
         [0068]    Realization of the process  50  is not limited to the above description. The following examples are used for illustrating the process  50 . 
         [0069]    The process  50  is similar to the process  30  except that the UE may keep (e.g., maintain) the WLAN measurement configuration, if the connection failure on the cellular network occurs. Comparing with the process  30 , an advantage of the process  50  is that when the UE recovers the connection failure on the cellular network with the cellular network (e.g. the BS or another BS), the cellular network does not need to configure the WLAN measurement configuration to the UE. The UE performs a connection recovery procedure (e.g. RRC connection reestablishment procedure) with the cellular network to recover the connection failure on the cellular network. In one example, the UE may perform the WLAN measurement and transmit a fifth WLAN measurement result on the connection to the cellular network according to the WLAN measurement configuration, after the UE recovers the connection failure on the cellular network. If the CWA is released by the UE due to the connection failure on the cellular network (e.g., the LTE RUE) or the connection recovery procedure, the cellular network may configure the CWA according to (e.g., in response to) the fifth WLAN measurement result quickly when a signal strength or quality of the WLAN in the fifth WLAN measurement result is good. The cellular network keeps (e.g., maintain) the WLAN measurement configuration in a context of the UE as well in response to the RRC connection reestablishment. 
         [0070]    Realization of any of the processes  30 - 50  is not limited to the above description. 
         [0071]    In one example, the packet above may be an internet protocol packet, a Convergence Protocol (PDCP) protocol data unit (PDU), a radio link control (RLC) PDU or a medium access control (MAC) PDU for LTE or 5G communication. In another example, the packet above is a newly defined PDU for CWA. 
         [0072]    In one example, the UE measures a beacon of the WLAN to get the signal strength or quality of the WLAN. 
         [0073]    It should be noted that although the above examples are illustrated to clarify the related operations of corresponding processes. The examples can be combined and/or modified arbitrarily according to system requirements and/or design considerations. 
         [0074]    Those skilled in the art should readily make combinations, modifications and/or alterations on the abovementioned description and examples. Any of the abovementioned 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 (known as a combination of a hardware device and computer instructions and data that reside as read-only software on the hardware device), an electronic system, or combination thereof. An example of the means be the communication device  20 . 
         [0075]    To sum up, the present invention provides a method and related communication device for handling the WLAN measurement configuration. Thus, the UE is able to handle the WLAN measurement configuration in response to the connection failure on the WLAN and/or the connection failure on the cellular network. As a result, the problem of handling the WLAN measurement configuration is solved. 
         [0076]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method 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.