PATENT DOCUMENT

Publication Number: US-9392536-B2
Application Number: US-201414291432-A
Country: US
Kind Code: B2

Title: Systems and methods for cell selection and reselection by improving system information reading procedure

Abstract:
Described herein are methods performed by user equipment (“UE”) for carrier aggregation deployment and organization in unlicensed bands. The method includes initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks, receiving a first information block, prior to reading a second information block, determining whether the target cell is suitable for the UE to camp on based on the first information block, and terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the first information block. The terminating may include comparing data from the first information block to data stored in a database. The method further includes determining whether the UE is in a stationary state or is in a state of motion, and using this information to improve cell selection delay on target cell.

Claims:
What is claimed is: 
     
       1. A method, comprising:
 at a user equipment (“UE”):
 initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks; 
 receiving the plurality of the information blocks; 
 reading a first information block of the plurality of information blocks; 
 prior to reading a second information block of the plurality of information blocks, determining whether the target cell is suitable for the UE to camp on based on the first information block; 
 terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the first information block; 
 reading the second information block when it is deteimined that the target cell is suitable for camping based on the first information block; 
 prior to reading a third information block, determining whether the target cell is suitable for the UE to camp on based on the second information block; and 
 terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the second information block. 
 
 
     
     
       2. The method of  claim 1 , further comprising:
 upon terminating the cell selection process, camping on a previously camped on cell. 
 
     
     
       3. The method of  claim 1 , further comprising:
 upon terminating the cell selection process, initiating a second cell selection process with a second target cell. 
 
     
     
       4. The method of  claim 1 , wherein the first information block is read at a radio resource control (“RRC”) layer from a physical (“PHY”) layer, and the RRC and PHY layers operate as parallel tasks. 
     
     
       5. A user equipment (“UE”), comprising:
 a non-transitory memory having a program stored thereon; and 
 a processor executing the program, wherein the execution of the program causes the processor to perform operations comprising:
 initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks; 
 receiving the plurality of the information blocks 
 reading a first information block of the plurality of information blocks; 
 prior to reading a second information block of the plurality of information blocks, 
 
 determining whether the target cell is suitable for the UE to camp on based on the first information block;
 terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the first information block; 
 reading the second information block when it is determined that the target cell is suitable for camping based on the first information block; 
 prior to reading a third information block determining whether the target cell is suitable for the UE to camp on based on the second information block; and 
 terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the second information block. 
 
 
     
     
       6. The UE of  claim 5 , wherein the operations further comprise:
 upon terminating the cell selection process, camping on a previously camped on cell. 
 
     
     
       7. The UE of  claim 5 , wherein the operations further comprise:
 upon terminating the cell selection process, initiating a second cell selection process with a second target cell. 
 
     
     
       8. The UE of  claim 5 , wherein the first information block is read at a radio resource control (“RRC”) layer from a physical (“PHY”) layer, and the RRC and PHY layers operate as parallel tasks. 
     
     
       9. A method, comprising:
 at a user equipment (“UE”):
 determining the UE is in a stationary state; 
 initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks; 
 receiving the plurality of information blocks; 
 reading the first information block of the plurality of information blocks; 
 prior to reading the second information block of the plurality of information blocks, comparing data from the first information block to data stored in a database; and 
 when the data from the first information block matches data stored in the database,
 terminating processing of further information blocks of the plurality of information blocks, 
 identifying the target cell as a suitable cell; 
 
 reading the second information block when it is determined that the target cell is suitable for camping based on the first information block; 
 prior to reading a third information block, determining whether the target cell is suitable for the UE to camp on based on the second information block; and 
 terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the second information block. 
 
 
     
     
       10. The method of  claim 9 , further comprising:
 storing data in the database relating to information blocks of a cell that the UE is currently camped on. 
 
     
     
       11. The method of  claim 9 , further comprising:
 when the data from the first information block does not match data stored in the database,
 processing the further information blocks of the target cell, and 
 determining whether the target cell is a suitable cell based on the plurality of information blocks. 
 
 
     
     
       12. The method of  claim 11 , further comprising:
 storing, when the target cell has been determined to be a suitable cell, data from the first information block in the database. 
 
     
     
       13. The method of  claim 9 , further comprising:
 determining the UE is in a state of motion; and 
 clearing the database. 
 
     
     
       14. A user equipment (“UE”), comprising:
 a non-transitory memory having a program stored thereon; and 
 a processor executing the program, wherein the execution of the program causes the processor to perform operations comprising:
 determining the UE is in a stationary state; 
 initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks; 
 receiving the plurality of information blocks; 
 reading the first information block of the plurality of information blocks; 
 prior to reading the second information block of the plurality of information blocks, comparing data from the first information block to data stored in a database; and 
 when the data from the first information block matches data stored in the database,
 terminating processing of further information blocks of the plurality of information blocks, and 
 identifying the target cell as a suitable cell; 
 
 reading the second information block when it is determined that the target cell is suitable for camping based on the first information block; 
 prior to reading a third information block, determining whether the target cell is suitable for the UE to camp on based on the second information block; and 
 terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the second information block. 
 
 
     
     
       15. The UE of  claim 14 , further comprising:
 storing data in the database relating to information blocks of a cell that the UE is currently camped on. 
 
     
     
       16. The UE of  claim 14 , further comprising:
 when the data from the first information block does not match data stored in the database,
 processing the further information blocks of the target cell, and 
 determining whether the target cell is a suitable cell based on the plurality of information blocks. 
 
 
     
     
       17. The UE of  claim 14 , further comprising:
 storing, when the target cell has been determined to be a suitable cell, data from the first information block in the database. 
 
     
     
       18. The UE of  claim 14 , further comprising:
 determining the UE is in a state of motion; and 
 clearing the database.

Description:
BACKGROUND 
     When a user powers on a user equipment (“UE”), in most case the UE is under a circumstance wherein it recognizes several base stations or cells (e.g., enhanced-Node B) around it. In some cases the UE may be in the coverage areas not only of the multiple base stations from one particular system operator, but also by multiple base stations from multiple system operators. Out of those many base stations, the UE may be able to register, or “camp,” on to only one specific base station. In order to determine which specific base station the UE is to register on, the UE goes through a decision making process to pick up a specific base station in which to register. Accordingly, this decision making process is called a “cell selection process.” 
     After the UE has selected a public land mobile network (“PLMN”) and performed the cell selection process, the UE may discover an appropriate cell camp. While camping on the cell, the UE may acquire a broadcast and the UE may record its presence in the area. After which, the UE may then receive paging information to be used to notify the UE of any incoming calls. Furthermore, the UE may establish a connection to the radio resource control (“RRC”). While camped on a cell, the UE may continuously measure the parameters of its current cell, as well as the neighboring cells (e.g., target cells) in order to camp on the strongest cell. Key parameters of the target cells are included within master information blocks (“MIBs”) and system information block (“SIBs”), which may be measured and uploaded to RRC layer of the UE to allow for control decisions to be made. 
     SUMMARY 
     Described herein are apparatus, systems and methods for cell selection and reselection by improving system information reading procedure. The method includes, at a UE, initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks, receiving the plurality of the information blocks, reading a first information block of the plurality of information blocks, prior to reading a second information block of the plurality of information blocks, determining whether the target cell is suitable for the UE to camp on based on the first information block, terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the first information block, reading the second information block when it is determined that the target cell is suitable for camping based on the first information block, prior to reading a third information block, determining whether the target cell is suitable for the UE to camp on based on the second information block, and terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the second information block. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows exemplary system information block data provided by one or more target cells during a search performed by a UE. 
         FIG. 2  shows a signaling diagram of a typical exchange of information between an RRC layer and a physical (“PHY”) layer of the UE during a conventional cell selection process. 
         FIG. 3  shows an exemplary system for improved system information reading procedure during cell selection and reselection according to an embodiment described herein. 
         FIG. 4  shows an exemplary signaling diagram for improved system information reading procedure during cell selection and reselection by according to an embodiment described herein. 
         FIG. 5  shows an exemplary method for improved system information reading procedure during cell selection and reselection corresponding to the signaling diagram of  FIG. 4 . 
         FIG. 6  shows a further exemplary method for improved system information reading procedure during cell selection and reselection based on a stationary state of the UE according to an embodiment described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Described herein are systems and methods for cell selection and reselection by improving system information reading procedure. A method comprising at a user equipment (“UE”) initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks, receiving a first information block, prior to reading a second information block, determining whether the target cell is suitable for the UE to camp on based on the first information block, and terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the first information block. 
     Further described herein is a user equipment (“UE”) comprising a non-transitory memory having a program stored thereon, and a processor executing the program, wherein the execution of the program causes the processor to perform operations comprising initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks, receiving a first information block, prior to reading a second information block, determining whether the target cell is suitable for the UE to camp on based on the first information block, and terminating the cell selection process when the target cell is determined to be unsuitable for camping based on the first information block. 
     Further described herein is a method comprising, at a user equipment (“UE”), determining the UE is in a stationary state; initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks; receiving a first information block of the plurality of information blocks; comparing data from the first information block to data stored in a database; and when the data from the first information block matches data stored in the database, terminating processing of further information blocks of the plurality of information blocks, and identifying the target cell as a suitable cell. 
     Further described herein is a user equipment (“UE”) comprising a non-transitory memory having a program stored thereon, and a processor executing the program, wherein the execution of the program causes the processor to perform operations comprising determining the UE is in a stationary state, initiating a cell selection process with a target cell, wherein the target cell sends a plurality of information blocks, receiving a first information block of the plurality of information blocks, comparing data from the first information block to data stored in a database and when the data from the first information block matches data stored in the database, terminating processing of further information blocks of the plurality of information blocks, and identifying the target cell as a suitable cell 
     The exemplary embodiments may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The exemplary embodiments show systems and methods for cell selection and reselection by improving system information reading procedure. As will be described in greater detail below, exemplary embodiments described herein may provide a pre-emptive mechanism for a mobile device such as a user equipment (“UE”) to achieve faster cell selection and reselection. For instance, the exemplary systems and methods may allow the UE to quickly move away from undesirable target cells and, instead, focus on desirable target cells for the UE. 
     The exemplary embodiments are described with reference to a UE performing cell selection and re-selection autonomously in mobility scenarios. More specifically, once the UE decides to select a cell, the UE then determines if a target cell is either suitable or acceptable before the UE can camp on the cell. Typically, this decision process takes place after the UE reads system information of the target cell. 
     A suitable target cell may be defined as a cell on which the UE may camp on to obtain normal service. The suitable cell may fulfill certain requirements such as the cell is part of a selected PLMN, or of a PLMN equivalent as considered by the UE according to information provided by the Non-Access-Stratum (“NAS”) protocol. Additional requirements may include that the cell is not barred, that the cell is not part of a list of forbidden Location Areas (“LAs”) for roaming, that the cell selection criteria are fulfilled, etc. 
     An acceptable target cell may be defined as a cell on which the UE may camp to originate limited service, such as originate emergency calls. The acceptable cell may fulfill certain requirements such as the cell is not barred and the cell selection criteria are fulfilled. Accordingly, the minimum set of requirements for the acceptable cell may be the requirements for initiating an emergency call in a Universal Terrestrial Radio Access Network (“UTRAN”). 
       FIG. 1  shows exemplary SIB data  100  provided by one or more target cells during a search performed by a UE. For instance, SIB 1  may contain information relevant when evaluating if a UE is allowed to access a cell. Furthermore, SIB 1  may contain cell access related information (e.g., a PLMN identity list, tracking area code, cell identity, etc.), information for cell selection (e.g., minimum required Rx level in the cell and offset), p-Max, frequency band indicator, scheduling information, time-division duplex (“TDD”) configuration, SI-window length and system information value tag, etc. SIB 2  may contain radio resource configuration information that is common for all UEs. This configuration information includes cell access barring information, random access channel (“RACH”) related parameters, idle mode paging configurations, physical uplink control channel (“PUCCH”) and physical uplink shared channel (“PUSCH”) configurations, uplink (“UL”) power control and sounding reference signal configurations, UL carrier frequency/bandwidth, etc. 
     Examples of various radio access technologies (“RATs”) may include Universal Mobile Telecommunications System (“UMTS”), Global System for Mobile communications (“GSM”), and Long-Term Evolution (“LTE”). Within each of the RATs, important system information messages may be different. For instance, in UMTS networks, there are master information blocks (“MIBs”) and system information blocks (e.g., SIB 1 , SIB 3 ). For GSM networks, there are system information messages (e.g., SI 1 , SI 2 ). For LTE networks, there are similar MIB, SIB 1 , SIB 2 , SIB 3  elements. Regardless of the various RATs implemented, system information messages, or SI messages, may be scheduled to be transmitted at different instances of time. Due to the fact that there may be multiple SI messages, the UE typically takes considerable amount of time in reading each of the SIs from target cells. 
       FIG. 2  shows a signaling diagram  200  of a typical exchange of information between an RRC layer  210  and a physical (“PHY”) layer  220  of a UE during a conventional cell selection process. In conventional designs, the RRC layer  210  may instruct the PHY layer  220  of the UE to read system information. As illustrated in the signaling diagram  200 , the RRC layer  210  may start  230  the cell selection process with a target cell of Cell X. The RRC layer  220  may then request  240  from the PHY layer  220  to receive a group of SIBs. The RRC layer  210  may then wait until a predetermined number of SIBs have been received at the UE (e.g., SIB  1  through SIB N) from Cell x. Specifically, the PHY layer  220  may send SIB  1   250 , followed by sending SIB  2   252 , and so forth through SIB N  254 . Upon sending the final information block, SIB N  254 , the PHY layer  220  may inform  260  the RRC layer  240  that the group of blocks (SIB  1  though SIB N) has been sent. 
     According to this conventional process, the UE will wait until the final block is received until the UE reads and processes  270  the information within each of the SIBs. It is only after the UE has read each of the SIBs until the UE determines whether the cell selection process should be terminated, wherein the RRC layer  210  sends a message  280  to the PHY layer  220  to stop the cell selection process. However, in several cases, the UE waiting to read and process all of the SIBs may not be required. For instance, information within the first SIB, or one of the first SIBs, may have rendered the target cell unsuitable. Accordingly, in this conventional scenario, the UE is wasting a considerable amount of time and battery power reading system information on a target cell on which the UE will ultimately not camp. 
       FIG. 3  shows an exemplary system  300  for improved system information reading procedure during cell selection and reselection according to an embodiment described herein. The system  300  may include a UE  310  in communication with a target cell  370  (e.g., eNodeB). The UE  310  may include an antenna  315  connected to a transceiver  320 , which is connected to a baseband processor  330 . The UE  310  may further include a memory  340  including a SIB database  345  that is accessible by the baseband processor  330 . As will be described in greater detail below, the UE  310  may further include a motion sensor component  350  and a baseband interface  360  connecting the motion sensor component  350  to the baseband processor  330 . Those skilled in the art will understand that the UE  310  may also include other components that are not shown in  FIG. 3 , for example, an application processor, a Bluetooth/WiFi transceiver, a display (e.g., a touchscreen), an input device (e.g., keypad), etc. 
     The transceiver  320  and the baseband processor  330  may be used to perform operations such as, but are not limited to, scanning the network for target cells, such as the target cell  370 , exchanging information with one or more target cells, etc. For instance, the exemplary target cell  370  may transmit signals via an antenna  375  that may be received by the antenna  315  of the UE  310 . 
     As noted above, the exemplary systems and methods described herein may allow for faster cell selection and reselection. In addition, the systems and methods may provide improved latency in higher layer applications that involve cell selection and reselection. Furthermore, the systems and methods may provide power saving advancements by eliminating unnecessary reading and processing of every SIB of a target cell that is not suitable for cell selection. 
       FIG. 4  shows an exemplary signaling diagram  400  for improved system information reading procedure during cell selection and reselection according to an embodiment described herein. The operations performed by the method  400  will be described in reference to the system  300  and its components described above with reference to  FIG. 3 . It may be considered that the baseband processor  330  implements at the RRC layer  410  and the transceiver  320  implements the PHY layer  420 . However, the exemplary embodiments are not limited to such an implementation, as the UE may implement network layers via any of a variety of hardware components. It is also considered that the RRC layer  410  and the PHY layer  430  may continue to operate as parallel tasks. Accordingly, the exemplary signaling diagram  400  may not have any impact on the parallelism of these two tasks. 
     The baseband processor  330  of the UE  310  implementing the RRC layer  410  may initiate a cell selection process by sending a message  430  to the transceiver  320  implementing the PHY layer  420 . In this example, it may be considered that the target cell  370  is the Cell X for which the cell selection process is initiated. The RRC layer  410  sends a request  440  to the PHY layer  420  to request a group of SIBs from the target cell  370 . 
     The PHY layer  420  then sends a message  450  with the first SIB (SIB  1 ) to the RRC layer  410 . Immediately upon receipt of message  450 , the RRC layer  410  may read and process  460  the information of SIB  1 . In this example, it is considered that SIB  1  has no issues, e.g., there is no information in SIB  1  that indicates the cell  370  is an unsuitable cell. While not specifically shown in  FIG. 4 , it may be considered that additional messages having SIB  2 , SIB  3 , etc., are sent from the PHY layer  420  to the RRC layer  410  and, as each of these messages are received, the RRC layer  410  reads and processes the SIB data from the message. Continuing with this pattern, the PHY layer  420  may send a message  470  to the RRC layer  410  including SIB P. The RRC layer  410  may read and process  480  the SIB P and then determine that the target cell  370  is not a suitable cell based on the data from SIB P. 
     According to the exemplary embodiments of the systems and methods described herein, the reading of the data of the first SIB occurs prior to, or contemporaneously with, the RRC layer  410  receiving a further system information block (e.g., SIB  2 ). In other words, before reading or processing the data from any subsequent SIBs (e.g., SIB  2  through SIB N), the RRC layer  410  determines whether any issues are present in the first SIB regarding the suitability of the target cell  370 . Therefore, as opposed to waiting to read and process each SIB until all SIBs are received, the RRC layer  410  may become aware of any such suitability issues as early as possible. As illustrated in  FIG. 4 , the exemplary RRC layer  410  may eliminate receiving, reading and processing of data from SIBs after it is determined that SIB P indicated that cell  370  is unsuitable (e.g., SIB P+1 through SIB N). 
     This is accomplished by the RRC layer  410  terminating the cell selection process by sending a stop cell selection/abort further SIB reading message  490  when the target cell  370  is determined to be unsuitable. Upon terminating the cell selection process, the PHY layer  420  may stop receiving any further SIBs from the target cell  370 . Furthermore, upon terminating the cell selection process with the first target cell  370 , the UE  310  may then either return to the currently camped cell if it is suitable, or the UE  310  may then initiate a new cell selection process with a different target cell of the network. 
       FIG. 5  shows an exemplary method  500  for improved system information reading procedure during cell selection and reselection corresponding to the signaling diagram  400  of  FIG. 4 . Furthermore, the operations performed by the method  400  will be described in reference to the system  300  and its components described above with reference to  FIG. 3 . 
     In step  510 , the UE  310  may initiate a cell selection process with a target cell. Once the process has been initiated, in step  520  the UE  310  may request SIBs from the target cell. In step  530 , the baseband processor  330  of the UE  310  may receive and process a first SIB (e.g., SIB  1 ). 
     At step  540 , the baseband processor  330  may determine whether the target cell is a suitable cell based on the information from the first SIB. If the target cell is determined to be unsuitable, the method  500  may advance to step  550  wherein the UE  310  terminates the cell selection process with the target cell and the method  500  ends. If the SIB indicates that the target cell is suitable, the method may advance to step  560 . 
     At step  560 , the baseband processor  330  may determine whether the current SIB (e.g., SIB  1 ) is the last SIB from the target cell. If the current SIB is determined to be the final SIB, the method  500  may advance to step  580  wherein the cell selection process is complete and the method  500  ends. If the current SIB is determined to not being the final SIB, the method may advance to step  570  wherein the baseband processor  330  receives and processes the next SIB (e.g., SIB  2 ). Upon receiving the next SIB (e.g., SIB  2 ), the method may return to step  540 , wherein the baseband processor  330  determines is the target cell is suitable based on the new information from the current SIB (e.g., SIB  2 ). Thus, the method  500  may process each current SIB, and prior to reading information from the next SIB, the baseband processor  330  may determine whether the target cell is suitable for the UE  310  to camp on based on the current SIB. 
       FIG. 6  shows a further exemplary method  600  for improved system information reading procedure during cell selection and reselection based on a stationary state of the UE  310  according to an embodiment described herein. Similar to  FIG. 4 , the operations performed by the method  600  will be described in reference to the system  300  and its components described above with reference to  FIG. 3 . As will described in detail below, the exemplary method  600  may utilize the SIB database  345  and the motion sensor component  350  of the UE  310 , wherein the method  600  may be implemented while the UE  310  is stationary. 
     In step  610 , the motion sensor component  350  of the UE  310  may determine a stationary state of the UE  310 . Specifically, the motion sensor component  350  may determine if the UE  310  is in either a stationary state or an in-motion state. The motion sensor component  350  may communicate the motion determination with the baseband processor  330  via the baseband interface  360 . If the UE  310  is determined to be in motion, the method  600  may advance to step  615 , wherein the UE  310  may clear the SIB database  345  and the method  600  may return to monitoring the UE  310  in step  610 . If the UE  310  is determined to be in a stationary state, the method  600  may advance to step  620 . 
     In step  620 , once the UE  310  is determined to be in a stationary state, the baseband processor  330  may store the SIBs of a current cell within the SIB database  345  of the memory  340 . For instance, the baseband processor  330  may store a combination of data, such as, but not limited to, frequency data, primary scrambling code (“PSC”) data, etc. of the current cell. As noted above, this combination stored within the SIB database  345  may remain valid until the motion state of the UE  310  changes. 
     In step  630 , the UE  310  may trigger a cell selection or reselection process while the UE remains in a stationary state. For instance, variations in the radio frequency (“RF”) signals may trigger a cell selection process, wherein the UE  310  attempts to select a new or a previously used target cell. 
     In step  640 , the UE  310  may receive initial SIB data from the target cell. For instance, the initial SIB data from the target cell may include a combination of data such as the frequency and PSC of the target cell. 
     In step  650 , the MIB may verify if a value tag has been changed. The UE  310  may perform this verification when the MIB is receives. The UE  310  may compare the value tag in the MIB with the value tag stored for the cell and PLMN. If the value tag in the MIB matches the stored value tag for the cell and PLMN, the UE  310  may use the stored SIBs and scheduling blocks stored for this cell and this PLMN. If the value tags differ, or if no information elements (IEs) are stored for the MIB, then the UE  310  may store the value tag for the MIB and any scheduling information included in the MIB. 
     In step  660 , the UE  310  may determine whether or not the initial SIB data received from the target cell is present in the SIB database  345 . If the initial SIB data is not in the database  345 , the method  600  may advance to step  670  wherein the UE  310  may continue to receive further SIB data from the target cell. However, if the initial SIB data is in the database  345 , the method  600  may advance to step  680  wherein the UE  310  may stop receiving further SIB data from the target cell, as there is no need to read any further SIBs. For instance, the database  345  may only include the target cells that have already been determined to be suitable. Thus, if the SIB data matches SIB data in the database  345 , the target cell has been previously determined to be suitable and there is no reason to continue to read any further SIBs. 
     In step  690 , the UE  310  may select the target cell as a suitable cell based on either the database entry from step  680  or the further SIB data from step  670 . Once the new target cell is selected, the method  600  may return to step  610 , wherein the motion sensor component  350  may determine a stationary state of the UE  310 . 
     The exemplary systems and methods described above may be implemented in any number of scenarios to improve the overall operations of the UE  310  in the network. One scenario may be a scenario in which PLMN searching during a “power on” process or when the UE  310  is out of coverage. Accordingly, the UE  310  may typically be required to read the SIs of a target cell in order to camp on the target cell during the PLMN search procedure. The exemplary systems and methods may eliminate any unwanted call in a much more efficient manner, and thus, the PLMN search procedure may be accomplished in less time. Furthermore, during a stationary scenario, the PLMN search may be finished even faster as the UE  310  may be required to read the least number of SIs before cell selection. 
     A further scenario may be a scenario of performing a home PLMN (“HPLMN”) scan in roaming. In roaming scenarios, the UE may periodically search for high-priority PLMN (“HPPLMN”) in order to find a HPLMN or the best roaming part. Accordingly, the UE  310  may find suitable cells faster using the exemplary systems and methods described above. For instance, the UE  310  may utilize the signaling diagram  400  when the UE  310  is mobile and either the signaling diagram  400  or the method  600  when the UE  310  is in a stationary state. 
     A further scenario may be a scenario during a limited service search. When any suitable target cell is not present to a UE, the UE may search for an acceptable cell on any PLMN in order to allow for limited service, such as the placement of emergency calls. If a target cell is barred or if the SI indicates that the cell is only for operator use, then the UE is restricted from camping on this target cell for emergency calls. Accordingly, if a particular SI indicates that the cell cannot be used by the UE for limited service, the UE may stop reading any further SIBs of that cell and initiate a cell selection process with a different target cell. 
     A further scenario may be a scenario after the end of a voice call and/or data call. In this scenario, a UE may attempt to acquire the best target cell on the current frequency after the voice/data call ends and the RRC connection is released. By utilizing the systems and methods described above, the UE may acquire the best target cell much faster, while reducing the chances of a page being missed. 
     A further scenario may be a scenario during a circuit switch fallback (“CSFB”). Typically, many networks redirect UEs to some frequency in circuit switch call-supported RATs (e.g., UMTS, GSM, etc.) from LTE after a UE tries to originate a voice call or receives a page for a voice call. During CSFB, the UE attempts to acquire a target cell on a given frequency, or some other frequency if the acquisition fails on a redirected frequency. The UE may then read the SIs before the UE can begin signaling with voice-supporting RATs. A large amount of time is typically devoted by the UE to reading this SIs, which in turn leads to a greater delay in call setup. By utilizing the systems and methods described above, the UE may reduce the overall call setup delay. 
     A further scenario may be a scenario during a redirection command from the network. For instance, during an active connection, the network may redirect the UE to another frequency or another RAT. Accordingly, the UE may be typically required to go to the redirected frequency or RAT in order to resume the ongoing call. By utilizing the systems and methods described above, the UE may reduce the overall call setup delay through improved call quality and throughput. 
     A further scenario may be a scenario involving paging performance, OOS recovery time in idel, and PCH (UMTS) states. By utilizing the systems and methods described above, the UE may reduce the time spent reading SIs in selection/reselection procedures, thereby providing faster OOS recovery and improved paging performance. 
     A further scenario may be a scenario involving reselections during data transfers in Cell_FACH in UMTS networks. By utilizing the systems and methods described above, the UE may reselect a better cell while data is ongoing in Cell_FACH/HS-FACH/HS-RACH state, thereby improving overall data throughput in these states as both the reselection process and the resumption of data transmission would be completed much faster. 
     A further scenario may be a scenario involving periodic and/or manual searchers for closed subscriber group (“CSG”) cells, such as a femtocell configured in CSG mode. In this scenario, a UE may perform periodic searches while camped on a macrocell in order to look for CSG cells. Accordingly, the UE may implement the method  400  while the UE is mobile to quickly find suitable target CSG cells. Furthermore, when the UE is stationary, the UE may implement the method  600  to quickly camp on CSG cell. 
     It will be apparent to those skilled in the art that various modifications may be made in the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Metadata:
Filing Date: 20140530
Publication Date: 20160712
Grant Date: 20160712
Priority Date: 20140530
Inventors: SHUKLA UMESH K.
RADHAKRISHNAN ARAVIND
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W48/16", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W48/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W48/16", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W48/16", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W48/20", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 54703436