METHOD AND APPARATUS FOR RESELECTING A CELL IN HETEROGENEOUS NETWORKS IN A WIRELESS COMMUNICATION SYSTEM

Abstract

The present disclosure provides a method for cell reselection in a wireless communication system in which various radio access technologies (RATs) coexist with each other. In a wireless communication system in which heterogeneous networks coexist with each other, the method of cell reselection between heterogeneous networks for a user equipment may include: receiving a system information block (SIB) containing cell reselection parameters from a corresponding base station; checking whether cell reselection parameters based on a cell selection quality value (Squal) are configured in the received SIB; and performing, when cell reselection parameter based on Squal are not configured, cell reselection based on a cell selection receive level value (Srxlev). The present disclosure may prevent the user equipment from performing unnecessary cell reselection.

Claims

1. A method for reselecting a cell by a terminal in a wireless communication system, the method comprising: receiving, from a base station, system information on an inter radio access technology (RAT) cell reselection; determining whether a quality value based cell reselection is supported if the system information includes a quality value for a cell reselection; and performing the cell reselection based on the determination.

2. The method of claim 1, wherein the cell reselection is performed based on the quality value, if the quality value based cell reselection is determined to be supported.

3. The method of claim 1, wherein the cell reselection is performed based on a reception level value, if the quality value based cell reselection is not determined to be supported.

4. The method of claim 1, wherein the method further comprises receiving, from the base station, system information for a plurality of RATs, and wherein the determining comprises determining whether the quality value based cell reselection is supported for the plurality of RATs among a RAT supported by a terminal.

5. The method of claim 4, wherein the quality value based cell reselection is determined to be supported when the terminal supports the quality value based cell reselection for all of the plurality of RATs.

6. A terminal for reselecting a cell in a wireless communication system, the terminal comprising: a transceiver configured to transmit and receive signals; and a controller coupled with the transceiver and configured to receive system information on an inter radio access technology (RAT) cell reselection from a base station, to determine whether a quality value based cell reselection is supported if the system information includes a quality value for a cell reselection, and to perform the cell reselection based on the determination.

7. The terminal of claim 6, wherein the controller is configured to perform the cell reselection based on the quality value, if the quality value based cell reselection is determined to be supported.

8. The terminal of claim 6, wherein the controller is configured to perform the cell reselection based on a reception level value, if the quality value based cell reselection is not determined to be supported.

9. The terminal of claim 6, wherein the controller is further configured to receive system information for a plurality of RATs from the base station and to determine whether the quality value based cell reselection is supported for the plurality of RATs among a RAT supported by a terminal.

10. The terminal of claim 9, wherein the quality value based cell reselection is determined to be supported when the terminal supports the quality value based cell reselection for all of the plurality of RATs.

11. A method for supporting a cell reselection by a base station in a wireless communication system, the method comprising: generating system information on an inter radio access technology (RAT) cell reselection; and transmitting, to a terminal, the generated system information, wherein the terminal receives the system information and determines whether a quality value based cell reselection is supported if the system information includes a quality value for a cell reselection, and wherein the cell reselection is performed by the terminal based on the determination.

12. The method of claim 11, wherein the cell reselection is performed by the terminal based on the quality value, if the quality value based cell reselection is determined to be supported.

13. The method of claim 11, wherein the cell reselection is performed by the terminal based on a reception level value, if the quality value based cell reselection is not determined to be supported.

14. The method of claim 11, wherein the method further comprises transmitting, to the terminal, system information for a plurality of RATs, and wherein the terminal determines whether the quality value based cell reselection is supported for the plurality of RATs among a RAT supported by the terminal.

15. The method of claim 14, wherein the quality value based cell reselection is determined to be supported when the terminal supports the quality value based cell reselection for all of the plurality of RATs.

16. A base station for supporting a cell reselection in a wireless communication system, the base station comprising: a transceiver configured to transmit and receive signals; and a controller coupled with the transceiver and configured to generate system information on an inter radio access technology (RAT) cell reselection and to transmit the generated system information to a terminal, wherein the terminal receives the system information and determines whether a quality value based cell reselection is supported if the system information includes a quality value for a cell reselection, and wherein the cell reselection is performed by the terminal based on the determination.

17. The base station of claim 16, wherein the cell reselection is performed by the terminal based on the quality value, if the quality value based cell reselection is determined to be supported.

18. The base station of claim 16, wherein the cell reselection is performed by the terminal based on a reception level value, if the quality value based cell reselection is not determined to be supported.

19. The base station of claim 16, wherein the controller is further configured to transmit system information for a plurality of RATs to the terminal, and wherein the terminal determines whether the quality value based cell reselection is supported for the plurality of RATs among a RAT supported by the terminal.

20. The base station of claim 19, wherein the quality value based cell reselection is determined to be supported when the terminal supports the quality value based cell reselection for all of the plurality of RATs.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 illustrates the architecture of the LTE system, to which the present disclosure is applied.

[0026] FIG. 2 illustrates a hierarchy of wireless protocols in the LTE system, to which the present disclosure is applied.

[0027] FIG. 3 illustrates a problem that may arise at cell reselection when multiple RATs coexist with each other.

[0028] FIG. 4 illustrates a first embodiment of inter-RAT cell reselection for a user equipment in the LTE system according to the present disclosure.

[0029] FIG. 5 is a flowchart illustrating operations of the user equipment using the first embodiment of inter-RAT cell reselection in the LTE system.

[0030] FIG. 6 illustrates a second embodiment of inter-RAT cell reselection for a user equipment in the LTE system according to the present disclosure.

[0031] FIG. 7 is a flowchart illustrating operations of the user equipment using the second embodiment of inter-RAT cell reselection in the LTE system.

[0032] FIG. 8 illustrates a third embodiment of inter-RAT cell reselection for a user equipment in the LTE system according to the present disclosure.

[0033] FIG. 9 is a flowchart illustrating operations of the user equipment using the third embodiment of inter-RAT cell reselection in the LTE system.

[0034] FIG. 10 is a block diagram of a user equipment according to an embodiment of the present disclosure.

[0035] FIG. 11 is a block diagram of a base station according to an embodiment of the present disclosure.

MODE FOR THE INVENTION

[0036] Hereinafter, embodiments of the present disclosure are described with reference to the accompanying drawings. Detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present disclosure.

[0037] The present disclosure relates to inter-RAT cell reselection for a user equipment in the LTE system.

[0038] FIG. 4 is a sequence diagram illustrating a first embodiment of inter-RAT cell reselection for a user equipment in the LTE system according to the present disclosure.

[0039] In FIG. 4, it is assumed that the UE 401 is a terminal of a latest version (e.g. Rel-9), supports Squal-based measurement, and remains in an ENB 403 after cell selection. Namely, the UE remains in the idle mode at an LTE base station.

[0040] The UE may receive preset System Information Blocks (SIBs) from the base station. Specifically, for cell selection/reselection to a neighboring base station employing a different RAT (e.g. GSM or UMTS base station), at operation 411, the UE receives a SIB containing corresponding cell selection/reselection parameters.

[0041] Upon SIB reception, at operation 413, the UE checks whether Squal-based cell reselection parameters for a target RAT (e.g. Thresh.sub.x,HighQ value or corresponding value) are contained in the received SIB. As described before, among cell reselection parameters, UNITS-related parameters may be obtained from SIB6 and GSM-related parameters may be obtained from SIB7.

[0042] If Squal-based cell reselection parameters are not contained in the received SIB, at operation 417, the UE determines to conduct cell reselection based on Srxlev measurement results.

[0043] If Squal-based cell reselection parameters are contained in the received SIB, at operation 415, the UE examines the version of the target RAT implemented internally to the UE.

[0044] If the version of the target RAT implemented internally is lower than the LTE version (or the mobile communication system version) of the UE (e.g. Rel-8 or lower), at operation 417, the UE determines to conduct cell reselection to the target RAT on the basis of Srxlev measurement results. If the version of the target RAT implemented internally is higher than or equal to the LTE version of the UE, at operation 417, the UE determines to conduct cell reselection to the target RAT on the basis of Squal measurement results. Examination of the version of a target RAT implemented internally to the UE is performed because, when the LTE version of the UE supports cell reselection based on Squal measurement results, inter-RAT cell reselection based on Squal measurement results can also be supported by the target RAT if the target RAT version is higher than or equal to the LTE version of the UE.

[0045] Upon determining to conduct inter-RAT cell reselection based on either Srxlev or Squal, at operation 419, the UE performs inter-RAT cell reselection accordingly. At operations 421 and 423, the UE receives reference signals from the target RATs. At operation 425, the UE performs measurement according to the determination made at operation 417.

[0046] FIG. 5 is a flowchart illustrating operations of a user equipment using the first embodiment of inter-RAT cell reselection in the LIE system.

[0047] At operation 501, the UE receives preset SIBs from the LTE base station. At operation 505, the UE obtains cell reselection parameters for a neighboring target RAT from the SIBs.

[0048] At operation 507, the UE checks whether Squal-based parameters are contained in the cell reselection parameters for a neighboring target RAT. If Squal-based parameters are not contained in the SIB, the UE proceeds to operation 511 at which the UE performs cell reselection based on Srxlev.

[0049] If Squal-based parameters are contained in the SIB, the UE proceeds to operation 509 at which the UE checks whether the version of the target RAT implemented internally to the UE is higher than or equal to the implemented LTE version of the UE.

[0050] If the version of the target RAT implemented internally is lower than the LTE version of the UE (e.g. Rel-8 or lower), the UE proceeds to operation 511 at which the UE performs cell reselection based on Srxlev.

[0051] If the version of the target RAT implemented internally is higher than or equal to the LTE version of the UE, the UE proceeds to operation 513 at which the UE performs cell reselection based on Squal.

[0052] Examination of the version of a target RAT implemented internally to the UE is performed because, when the LTE version of the UE supports Squal, Squal-based measurement can also be supported by the target RAT if the target RAT version is higher than or equal to the LTE version of the UE.

[0053] FIG. 6 is a sequence diagram illustrating a second embodiment of inter-RAT cell reselection for a user equipment in the LTE system according to the present disclosure. In FIG. 6, it is assumed that the UE 601 is a terminal of the latest version (e.g. Rel-9), supports cell reselection based on Squal measurement results, and remains in an ENB 603 after cell selection. Namely, the UE remains in the idle mode at an LTE base station.

[0054] At operation 611, the UE receives a preset SIB from the LTE base station. At operation 613, the UE checks whether Squal-based cell reselection parameters for a target RAT are configured.

[0055] If Squal-based cell reselection parameters for a target RAT are configured, at operation 615, the UE checks whether the target RAT to be reselected (e.g. GSM or UMTS) supports Squal-based cell reselection. For example, when UMTS is selected by the UE as a target RAT, the UE checks whether it is possible to conduct Squal-based inter-RAT cell reselection from the UMTS cell to the LTE cell.

[0056] If the target RAT does not support Squal-based cell reselection, at operation 617, the UE determines to conduct Srxlev-based cell reselection. If the target RAT supports Squal-based cell reselection, at operation 617, the UE determines to conduct Squal-based cell reselection under assumption that it is possible to conduct Squal-based cell reselection at the target RAT cell after cell reselection to the target RAT cell.

[0057] Upon determining to conduct inter-RAT cell reselection based on either Srxlev or Squal, at operation 619, the UE performs inter-RAT cell reselection accordingly. At operations 621 and 623, the UE receives reference signals from the target RATs. At operation 625, the UE performs measurement according to the determination made at operation 617.

[0058] FIG. 7 is a flowchart illustrating operations of the user equipment using the second embodiment of inter-RAT cell reselection in the LTE system.

[0059] At operation 701, the UE in the idle mode at an LTE cell receives preset SIBs from the LTE base station. At operation 703, the UE obtains cell reselection parameters for a neighboring target RAT from the SIBs.

[0060] At operation 705, the UE checks whether Squal-based parameters are contained in the cell reselection parameters for a neighboring target RAT. If Squal-based parameters are not contained in the SIB, the UE proceeds to operation 709 at which the UE performs cell reselection based on Srxlev.

[0061] If Squal-based parameters are contained in the SIB, the UE proceeds to operation 707 at which the UE checks whether the target RAT supports Squal-based cell reselection. For example, when UMTS is selected by the UE as a target RAT, the UE checks whether it is possible to conduct Squal-based inter-RAT cell reselection from the UMTS cell to the LTE cell. If the target RAT does not support Squal-based cell reselection, the UE proceeds to operation 709 at which the UE determines to conduct Srxlev-based cell reselection.

[0062] If the target RAT supports Squal-based cell reselection, the UE proceeds to operation 711 at which the UE determines to conduct Squal-based cell reselection under assumption that it is possible to conduct Squal-based cell reselection at the target RAT cell after cell reselection to the target RAT cell.

[0063] FIG. 8 illustrates a third embodiment of inter-RAT cell reselection for a user equipment in the LTE system according to the present disclosure.

[0064] FIG. 8 is a sequence diagram illustrating a third embodiment of inter-RAT cell reselection for a user equipment in the LTE system according to the present disclosure.

[0065] In FIG. 8, it is assumed that the UE 801 is a terminal of the latest version (e.g. Rel-9), supports cell reselection based on Squal measurement results, and remains in an ENB 803 after cell selection. Namely, the UE remains in the idle mode at an LTE base station.

[0066] At operation 811, the UE receives preset SIBs from the base station and obtains cell selection/reselection parameters for neighboring base stations employing different RATs (e.g. GSM and UMTS base stations).

[0067] At operation 813, the UE checks whether cell reselection parameters based on Squal measurement results are contained as cell reselection information for a neighboring RAT in a designated SIB.

[0068] If cell reselection parameters based on Squal measurement results are not contained as cell reselection information for a neighboring RAT in a designated SIB, at operation 817, the UE determines to conduct cell reselection to the RAT based on Srxlev measurement results.

[0069] If cell reselection parameters based on Squal measurement results are contained as cell reselection information for a neighboring RAT in a designated SIB, at operation 815, the UE checks whether inter-RAT cell reselection based on Squal measurement results is supported by all neighboring RATs that are signaled through designated SIBs and supported by the UE. That is, whether all neighboring RATs support cell reselection based on Squal measurement results for the UE is examined.

[0070] If one of the neighboring RATs signaled through the designated SIBs among all other RATs supported by the UE does not support inter-RAT cell reselection based on Squal measurement results, at operation 817, the UE determines to conduct cell reselection to the corresponding RAT (the RAT whose cell reselection information is configured in the designated SIB) based on Srxlev measurement results.

[0071] If all the neighboring RATs signaled through the designated SIBs among all other RATs supported by the UE support inter-RAT cell reselection based on Squal measurement results, at operation 817, the UE determines to conduct cell reselection to the corresponding RAT (the RAT whose cell reselection information is configured in the designated SIB) based on Squal measurement results. For example, if any of neighboring RATs does not support Squal-based cell reselection, the UE does not perform cell reselection to a different RAT supporting Squal-based cell reselection.

[0072] Upon determining to conduct inter-RAT cell reselection based on either Srxlev or Squal, at operation 819, the UE performs inter-RAT cell reselection accordingly. At operations 821 and 823, the UE receives reference signals from the target RAT base stations. At operation 825, the UE performs measurement according to the determination made at operation 817.

[0073] An example for the above scheme is described. It is assumed that the UE supports LTE, UMTS, GSM and CDMA2000 RATs. It is also assumed that cell reselection parameters based on Squal measurement results are configured as cell reselection information for neighboring UMTS in a designated SIB. The UE identifies cell reselection information for neighboring RATs through designated SIBs. When cell reselection parameters for UMTS and GSM only are configured as neighboring system information in the designated SIBs, the UE regards CDMA2000 as a non-neighboring RAT and does not consider CDMA2000 for reselection. Hence, among RATs supported by the UE, neighboring RATs signaled through designated SIBs are GSM and UNITS. Only if the UE supports inter-RAT cell reselection based on Squal measurement results at both GSM and UMTS (e.g. cell reselection to LTE), the UE performs inter-RAT cell reselection based on Squal measurement results to UMTS (the neighboring RAT whose cell reselection information is configured based on Squal measurement results in the designated SIB). That is, the UE performs Squal-based cell reselection only when the UE supports Squal-based measurement at both GSM and UMTS for cell reselection to LTE. If the UE does not support Squal-based cell reselection from GSM to LTE, although the UE supports Squal-based cell reselection from UMTS to LTE, the UE performs Srxlev-based cell reselection to UMTS (the neighboring RAT whose cell reselection information is configured based on Squal measurement results in the designated SIB).

[0074] FIG. 9 is a flowchart illustrating operations of the user equipment using the third embodiment of inter-RAT cell reselection in the LTE system.

[0075] At operation 901, the UE in the idle mode at an LTE cell receives designated SIBs from the LTE base station.

[0076] At operation 905, the UE obtains cell reselection parameters for a neighboring target RAT from the SIBs. At operation 907, the UE checks whether Squal measurement-based parameters are contained in the cell reselection parameters for a neighboring target RAT. If cell reselection parameters based on Squal measurement results are not configured in the SIB, the UE proceeds to operation 911 at which the UE performs cell reselection to the target RAT on the basis of Srxlev measurement results.

[0077] If cell reselection parameters based on Squal measurement results are configured in the SIB, the UE proceeds to operation 909 at which the UE checks whether inter-RAT cell reselection based on Squal measurement results is supported by all neighboring RATs that are signaled through designated SIBs and supported by the UE.

[0078] If one of the neighboring RATs signaled through the designated SIBs among all other RATs supported by the UE does not support inter-RAT cell reselection based on Squal measurement results (i.e. if any of the neighboring RATs does not support cell reselection based on Squal measurement results), the UE proceeds to operation 911 at which the UE conducts cell reselection to the corresponding RAT (the RAT whose cell reselection information is configured based on Squal measurement results in the designated SIB) based on Srxlev measurement results.

[0079] If all the neighboring RATs signaled through the designated SIBs among all other RATs supported by the UE support inter-RAT cell reselection based on Squal measurement results, the UE proceeds to operation 913 at which the UE conducts cell reselection to the corresponding RAT (the RAT whose cell reselection information is configured based on Squal measurement results in the designated SIB) based on Squal measurement results.

[0080] An example for the above scheme is described. It is assumed that the UE supports LTE, UMTS, GSM and CDMA2000 RATs. It is also assumed that cell reselection parameters based on Squal measurement results are configured as cell reselection information for neighboring UMTS in a designated SIB (operations 905 and 907). The UE identifies cell reselection information for neighboring RATs through designated SIBs. When cell reselection parameters for UMTS and GSM only are configured as neighboring system information in the designated SIBs, the UE regards CDMA2000 as a non-neighboring RAT and does not consider CDMA2000 for reselection. Hence, among RATs supported by the UE, neighboring RATs signaled through designated SIBs are GSM and UMTS. Only if the UE supports inter-RAT cell reselection based on Squal measurement results at both GSM and UMTS (e.g. cell reselection from GSM and UMTS to LTE) (operation 909), the UE performs inter-RAT cell reselection to UMTS (the neighboring RAT whose cell reselection information is configured based on Squal measurement results in the designated SIB) on the basis of Squal measurement results (operation 913). That is, the UE performs Squal-based cell reselection only when the UE supports Squal-based measurement at both GSM and UMTS for cell reselection to LTE. If the UE does not support Squal-based cell reselection from GSM to LTE (operation 909), although the UE supports Squal-based cell reselection from UMTS to LTE, the UE performs Srxlev-based cell reselection to UMTS (the neighboring RAT whose cell reselection information is configured based on Squal measurement results in the designated SIB) (operation 911).

[0081] FIG. 10 is a block diagram of a user equipment according to an embodiment of the present disclosure.

[0082] Referring to FIG. 10, the user equipment may include a transceiver unit 1005, a control unit 1010, a mux/demux unit 1015, a control message handler 1030, and various higher layer units 1020 and 1025.

[0083] The transceiver unit 1005 receives data and control signals through downlink channels of a serving cell and sends data and control signals through uplink channels. When multiple serving cells are configured, the transceiver unit 1005 may send and receive data and control signals through the multiple serving cells.

[0084] The mux/demux unit 1015 multiplexes data coming from the higher layer units 1020 and 1025 or the control message handler 1030, and demultiplexes data received by the transceiver unit 1005 and forwards the demultiplexed data to the higher layer units 1020 and 1025 or the control message handler 1030.

[0085] The control message handler 1030 processes a control message received from a base station and performs a corresponding operation. For example, when DRX related parameters are received, the control message handler 1030 forwards the same to the control unit 1010.

[0086] The higher layer units 1020 and 1025 may be configured on a service basis. The higher layer units 1020 and 1025 may process user data generated by service applications such as File Transfer Protocol (FTP) and Voice over Internet Protocol (VoIP) and forward the processed user data to the mux/demux unit 1015, and delivers data coming from the mux/demux unit 1015 to appropriate service applications at the higher layer.

[0087] The control unit 1010 examines scheduling commands such as UL grants received through the transceiver unit 1005, and controls the transceiver unit 1005 and the mux/demux unit 1015 so that uplink transmissions are performed at proper points in time with appropriate transmission resources. The control unit 1010 controls the transceiver unit 1005 for DRX operation and CSI/SRS transmission.

[0088] Particularly, in various embodiments of the present disclosure, the control unit 1010 receives a SIB containing cell reselection parameters from a corresponding base station, and examines whether Squal-based cell reselection parameters are configured in the received SIB. If Squal-based cell reselection parameters are not configured, the control unit 1010 controls an operation to perform Srxlev-based cell reselection.

[0089] In the first embodiment, if Squal-based cell reselection parameters are configured, the control unit 1010 examines the version of a target RAT to be reselected (or a target mobile communication system) implemented internally to the UE. The control unit 1010 compares the version of the target RAT implemented internally with the version of a preset RAT of the UE. If the version of the target RAT implemented internally is higher than or equal to the version of the preset RAT of the UE, the control unit 1010 may control an operation to conduct cell reselection based on Squal measurement results. If the version of the target RAT implemented internally is lower than the version of the preset RAT of the UE, the control unit 1010 may control an operation to conduct cell reselection based on Srxlev.

[0090] In the second embodiment, if Squal-based cell reselection parameters are configured, the control unit 1010 checks whether a target RAT to be reselected (or a target mobile communication system) supports cell reselection based on Squal measurement results. If the target RAT supports Squal-based cell reselection, the control unit 1010 may control an operation to perform cell reselection based on Squal measurement results. If the target RAT does not support Squal-based cell reselection, the control unit 1010 may control an operation to perform Srxlev-based cell reselection.

[0091] In the third embodiment, if Squal-based cell reselection parameters are configured, the control unit 1010 checks whether inter-RAT cell reselection based on Squal measurement results is supported by all neighboring RATs (or neighboring mobile communication systems) that are signaled through designated SIBs and supported by the UE. If all the neighboring RATs support inter-RAT cell reselection based on Squal measurement results, the control unit 1010 may control an operation to conduct cell reselection based on Squal measurement results. If any of the neighboring RATs does not support inter-RAT cell reselection based on Squal measurement results, the control unit 1010 may control an operation to conduct Srxlev-based cell reselection.

[0092] FIG. 11 is a block diagram of a base station according to an embodiment of the present disclosure. The base station of FIG. 11 may include a transceiver unit 1105, a control unit 1110, a mux/demux unit 1120, a control message handler 1135, various higher layer units 1125 and 1130, and a scheduler 1115.

[0093] The transceiver unit 1105 sends data and control signals through a downlink carrier and receives data and control signals through an uplink carrier. When multiple carriers are configured, the transceiver unit 1105 may send and receive data and control signals through the multiple carriers.

[0094] The mux/demux unit 1120 multiplexes data coming from the higher layer units 1125 and 1130 or the control message handler 1135, and demultiplexes data received by the transceiver unit 1105 and forwards the demultiplexed data to the higher layer units 1125 and 1130, the control message handler 1135 or the control unit 1110. The control message handler 1135 processes a control message received from a user equipment and performs a corresponding operation, and generates a control message to be sent to a user equipment and forwards the control message to a lower layer.

[0095] The higher layer units 1125 and 1130 may be configured on a terminal and service basis. The higher layer units 1125 and 1130 may process user data generated by service applications such as FTP and VoIP and forward the processed user data to the mux/demux unit 1120, and process data coming from the mux/demux unit 1120 and deliver the processed data to service applications at the higher layer.

[0096] The control unit 1110 determines CSI/SRS transmission times of user equipments and controls the transceiver unit 1105 accordingly.

[0097] The scheduler 1115 allocates transmission resources to a user equipment at appropriate points in time in consideration of buffer states, channel states and active time of the user equipment, and controls the transceiver unit 1105 to send or receive a signal to or from the user equipment.

[0098] Use of the proposed method enables sensible reselection of a cell without unnecessary cell reselection in a network wherein heterogeneous radio access technologies coexist with each other.

[0099] While the present disclosure has been shown and described with reference to various embodiments thereof, it should be understood by those skilled in the art that many variations and modifications of the method and apparatus described herein will still fall within the spirit and scope of the present disclosure as defined in the appended claims and their equivalents.