WO2016206009A1

WO2016206009A1 - Techniques for managing redirection of wireless device between multiple radio access technologies

Info

Publication number: WO2016206009A1
Application number: PCT/CN2015/082182
Authority: WO
Inventors: Xuepan GUAN; Jie Mao; Jun Deng
Original assignee: Qualcomm Incorporated
Priority date: 2015-06-24
Filing date: 2015-06-24
Publication date: 2016-12-29

Abstract

Described herein are various aspects related to managing redirection between radio access technologies (RAT) at a user equipment (UE). A redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT can be initiated based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold. It can be determined, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE. The UE can be reverted to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list. The UE can refrain from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list.

Description

TECHNIQUES FOR MANAGING REDIRECTION OF A WIRELESS DEVICE BETWEEN MULTIPLE RADIO ACCESS TECHNOLOGIES

BACKGROUND

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power) . Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency divisional multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example of a telecommunication standard is Long Term Evolution (LTE) . LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP) . It is designed to better support mobile broadband Internet access by improving spectral efficiency, lower costs, improve services, make use of new spectrum, and better integrate with other open standards using OFDMA on the downlink (DL) , SC-FDMA on the uplink (UL) , and multiple-input multiple-output (MIMO) antenna technology. Other examples of telecommunication standards include UMTS technologies such as wideband CDMA (W-CDMA) , High Speed Downlink Packet Access (HSDPA) , High Speed Uplink Packet Access (HSUPA) , High Speed Packet Access Plus (HSPA+) , global system for mobile communications (GSM) , etc.

A user equipment (UE) communicating with a network using TD-SCDMA can detect an event 3A corresponding to the estimated quality of a currently used Universal Terrestrial Radio Access Network (UTRAN) frequency in the TD-SCDMA network being below a threshold and an estimated quality of another radio access technology (RAT) frequency (e.g., an LTE frequency) being above another threshold. This can occur, for example, when the UE is in a packet-switched (PS) call or mode at the TD-SCDMA network. When the UE detects and reports an event 3A, the TD-SCDMA network (or a component thereof, such as a base station) can redirect the UE to another system that uses another RAT (e.g., LTE) based on a frequency reported in the event 3A. The redirection may be accomplished via a radio resource control (RRC) connection release message that may specify the frequency of the system to which the UE is being redirected. Upon redirecting to the LTE system, the UE may determine, as part of a procedure to establish a connection in LTE, that a tracking area (TA) of the cell is in a list of forbidden TAs related to the UE, and thus the UE may revert to the TD-SCDMA network. As the PS call or mode continues, the UE may continue to detect the event 3A and thus ping pong between the TD-SCDMA and LTE systems, which may result in decrease in performance and efficiency at the UE.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In an example, a method of managing redirection between radio access technologies (RAT) at a user equipment (UE) is provided. The method includes initiating a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold, determining, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE, reverting the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list, and refraining from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list.

In another example, an apparatus for managing redirection between RATs at a UE is provided. The apparatus includes a redirecting component configured to: initiate a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold； determine, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE； and revert the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list. The apparatus further includes a cell evaluating component configured to refrain from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on the redirecting component determining that the one or more parameters associated with the target cell are in the forbidden list.

In another example, an apparatus for managing redirection between RATs at a UE is provided. The apparatus includes means for initiating a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold, means for determining, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE, means for reverting the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list, and means for refraining from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list.

In a further example, a computer-readable medium comprising code executable by a computer for managing redirection between RATs at a UE is provided. The code includes code for initiating a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold, code for determining, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE, code for reverting the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list, and code for refraining from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements.

FIG. 1 is a block diagram illustrating an example wireless communications system according to aspects described herein.

FIG. 2 is a flow diagram comprising of an example method for managing redirection of wireless devices among different radio access technologies.

FIG. 3 is a block diagram illustrating an example wireless communications system according to aspects described herein.

FIG. 4 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.

FIG. 5 is a block diagram conceptually illustrating an example of a Node B in communication with a UE in a telecommunications system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known components are shown in block diagram form in order to avoid obscuring such concepts. In an aspect, the term “component” as used herein may be one of the parts that make up a system, may be hardware, firmware, and/or software, and may be divided into other functions.

Various aspects described herein relate to managing redirection of a user equipment (UE) or other wireless network node between radio access technologies (RAT) while avoiding ping ponging between the RATs. For example, when a UE is redirected from a first cell of a first RAT to a second cell of a second RAT, if the UE determines that the second cell of the second RAT has one or more properties that are in a list of forbidden properties, the UE can revert to the first cell of the first RAT. In addition, the UE can refrain from evaluating the second cell (e.g., for at least a period of time) based on determining that the one or more properties are in the list of forbidden properties. This can ensure that the UE does not ping pong between the first cell and second cell though the second cell may be determined to have a stronger signal quality or power than the first cell.

FIG. 1 is a schematic diagram illustrating a system 100 for wireless communication, according to an example configuration. FIG. 1 includes a UE 102 operable to communicate with at least one network entity 104 and/or 106 for receiving access to a wireless network. For example, network entity 104 and/or 106 may provide one or more cells that facilitate communicating with one or more UEs 102 to provide the wireless network access. In addition, the one or

more network entities

104 and 106 may operate using different RATs (e.g., TD-SCDMA, LTE, GSM, etc. ) . Though one UE 102 is shown, it is to be appreciated that network entity 104 and/or 106 can communicate with multiple UEs 102 in one or more provided cells. Moreover, in one example, UE 102 can be configured with multiple subscriber identity modules (SIM) to communicate from the UE 102 using two or more subscriptions, which may be related to two or more SIMs operable at the UE 102. Thus, for example, the two or more subscriptions may correspond to the separate RATs utilized by

network entities

104 and 106.

UE 102 may comprise any type of mobile device, such as, but not limited to, a smartphone, cellular telephone, mobile phone, laptop computer, tablet computer, or other portable networked device that can be a standalone device, tethered to another device (e.g., a modem connected to a computer) , and/or the like. In addition, UE 102 may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a mobile communications device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. In general, UE 102 may be small and light enough to be considered portable and may be configured to communicate wirelessly via an over-the-air communication link using one or more OTA communication protocols described herein. Additionally, in some examples, UE 102 may be configured to facilitate communication on multiple separate networks via multiple separate subscriptions, multiple radio links, and/or the like.

Furthermore, network entity 104 and/or 106 may comprise one or more of any type of network module, such as an access point, a macro cell, including a base station (BS) , node B, eNodeB (eNB) , a relay, a peer-to-peer device, an authentication, authorization and accounting (AAA) server, a mobile switching center (MSC) , a mobility management entity (MME) , a radio network controller (RNC) , a small cell, etc. As used herein, the term “small cell” may refer to an access point or to a corresponding coverage area of the access point, where the access point in this case has a relatively low transmit power or relatively small coverage as compared to, for example, the transmit power or coverage area of a macro network access point or macro cell. For instance, a macro cell may cover a relatively large geographic area, such as, but not limited to, several kilometers in radius. In contrast, a small cell may cover a relatively small geographic area, such as, but not limited to, a home, a building, or a floor of a building. As such, a small cell may include, but is not limited to, an apparatus such as a BS, an access point, a femto node, a femtocell, a pico node, a micro node, a Node B, eNB, home Node B (HNB) or home evolved Node B (HeNB) . Therefore, the term “small cell, ” as used herein, refers to a relatively low transmit power and/or a relatively small coverage area cell as compared to a macro cell. Additionally, network entity 104 and/or 106 may communicate with one or more other network entities of wireless and/or core networks

Additionally, network entity 104 and/or 106 can utilize one or more of wide-area networks (WAN) , wireless networks (e.g. 802.11 or cellular network) , the Public Switched Telephone Network (PSTN) network, ad hoc networks, personal area networks (e.g.

) or other combinations or permutations of network protocols and network types. Such network (s) may include a single local area network (LAN) or wide-area network (WAN) , or combinations of LANs or WANs, such as the Internet. Such networks may comprise a Wideband Code Division Multiple Access (W-CDMA) system, and may communicate with one or more UEs 102 according to this standard. As those skilled in the art will readily appreciate, various aspects herein may be extended to other telecommunication systems, network architectures and communication standards. By way of example, various aspects may be extended to other Universal Mobile Telecommunications System (UMTS) systems such as Time Division Synchronous Code Division Multiple Access (TD-SCDMA) , High Speed Downlink Packet Access (HSDPA) , High Speed Uplink Packet Access (HSUPA) , High Speed Packet Access Plus (HSPA+) and Time-Division CDMA (TD-CDMA) . Various aspects may also be extended to systems employing Long Term Evolution (LTE) (in FDD, TDD, or both modes) , LTE-Advanced (LTE-A) (in FDD, TDD, or both modes) , CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16

IEEE 802.20, Ultra-Wideband (UWB) , Bluetooth, and/or other suitable systems. In yet another example, the networks may include Global System for Mobile Communications (GSM) employing TDMA or similar networks that support circuit-switched communications. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system. The various devices coupled to the network (s) (e.g., UEs 102, network entity 104, network entity 106) may be coupled to a core network via one or more wired or wireless connections.

Referring to FIGs. 1 and 2, aspects are depicted with reference to one or more components and one or more methods that may perform the actions or functions described herein. Although the operations described below in FIG. 2 are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Moreover, it should be understood that the following actions or functions may be performed by a specially-programmed processor, a processor executing specially-programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component capable of performing the described actions or functions.

FIG. 1 includes a UE 102 with a communicating component 110 operable to perform functions described herein. For example, communicating component 110 may include, or may be in communication with, a cell evaluating component 112 for evaluating one or more cells or related network entities for possible redirection thereto, a redirecting component 114 that can redirect the UE 102 to the one or more cells or related network entities, and a forbidden list managing component 116 for maintaining or receiving one or more forbidden lists of cell parameters. For example, redirection, as used herein, may refer to substantially any process by which the UE 102 can switch between cells with which the UE 102 communicates, where the cells, or related network entities, may utilize different RATs. For example, a redirection may include an inter-RAT handover (e.g., when the UE 102 is in connected mode) , cell reselection (e.g., when the UE 102 is in idle mode) , etc., which may also include switching among subscriptions in the UE 102 to associate with the different RAT. In addition, for example, the forbidden list of cell parameters may relate to substantially any list of parameters that can be advertised by a cell, where certain values populated in the forbidden list may cause the UE 102 to not complete redirection to the cell. Some examples may include forbidden lists of tracking areas (TA) , location areas (LA) , etc. where certain TAs, LAs, etc. advertised by a cell may cause the UE 102 to not establish a connection with the cell (e.g., and/or terminate an ongoing connection establishment with the cell) .

FIG. 2 illustrates a method 200 for managing redirection of a UE between cells of different RATs. Method 200 includes, at Block 202, initiating a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold. For example, redirecting component 114 can initiate the redirection of the UE 102 from the serving cell (e.g., a cell provided by network entity 104) that utilizes the serving RAT to the target cell (e.g., a cell provided by the network entity 106) that utilizes the RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold. In an example, cell evaluating component 112 can evaluate one or more cells to determine whether to perform the redirection based on a time period, a detected event, etc. For instance, cell evaluating component 112 can periodically evaluate neighboring cells in an attempt to locate a target cell having a target signal quality that achieves the target threshold. In an example, cell evaluating component 112 can measure signals received from cells of RATs other than the serving RAT during one or more measurement gaps, which may include tuning radio frequency (RF) resources of communicating component 110 to other frequencies in an attempt to discover the one or more target cells. As described, initiating the redirection may include initiating a connected mode handover of the UE 102, an idle mode reselection of the UE 102, etc.

Redirecting component 114 can initiate the redirection by reporting an event to the network entity 104 indicating that the signal quality of the target cell achieves a threshold. Moreover, redirecting component 114 can initiate redirection (e.g., report the event to the network entity 104) further based at least in part on determining that a serving signal quality of the serving cell fails to achieve a serving threshold. For instance, the target and serving thresholds may be configured by the serving cell (e.g., by network entity) , or another component of the network that utilizes the serving RAT, to the UE 102. In an example, the serving threshold can be less than the target threshold. In addition, for example, the target and serving signal qualities may relate to one or more signal quality or power measurements (e.g., received signal strength indicator (RSSI) , reference signal received power (RSRP) , reference signal received quality (RSRQ) , etc. ) measured by the UE 102 of the signals received from the cells or related network entities (e.g., network entities 104 and/or 106) .

Method 200 also includes, at Block 204, determining, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE. Redirecting component 114 can determine, as part of the redirection, that the one or more parameters associated with the target cell are in the forbidden list related to the UE 102. In an example, forbidden list managing component 116 can maintain the list of forbidden parameters (e.g., a list of forbidden value for the one or more parameters) . The list may include a list of forbidden tracking areas (TA) , location areas (LA) , etc. Thus, for example, determining that the one or more parameters are in the forbidden list at Block 204 may include, at Block 206, determining that a tracking area of the target cell is in a forbidden list for the UE. Redirecting component 114 may determine that the tracking area of the target cell is in the forbidden list for the UE 102, where the forbidden list of TAs is maintained by forbidden list managing component 116. For example, forbidden list managing component 116 may receive the list, receive updates to the list, etc. from network configurations received from one or more network entities, based on user input, etc. For example, one or more indications of the TA, LA, etc. of the target cell may be received from the target cell as part of attempting to establish a connection thereto (e.g., in system information, dedicated configuration information, etc. as received from the target cell) .

Method 200 further includes, at Block 208, reverting the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list. Redirecting component 114 may revert the UE 102 to the serving cell (e.g., a cell provided by network entity 104) based at least in part on determining that the one or more parameters associated with the target cell (e.g., a cell provided by network entity 106) are in the forbidden list. As described, this can include determining a TA, LA, etc. associated with the target cell are in the forbidden list. Reverting the UE 102 can include the UE 102 continuing to utilize a connection with the serving cell, reestablishing a connection with the serving cell, etc.

Method 200 also includes, at Block 210, refraining from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list. Cell evaluating component 112 can refrain from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list. For example, cell evaluating component 112 can refrain from evaluating the target cell for a period of time (e.g., a number of seconds, such as 180 seconds) , which may be a configured by the network (e.g., by network entity 104 or other component of the network of the serving RAT) , etc. In this regard, the UE 102 may stay connected with the network entity 104 or another network entity of the serving RAT and avoid ping ponging between the serving RAT and the target RAT. In addition, for example, refraining from evaluating the cell can include refraining from storing measurements of the cell for reporting to the serving cell, refraining from detecting an event 3A and/or otherwise reporting redirection information to the serving cell in an attempt to cause handover of the UE 102 in connected mode (though measurement information may have been obtained for the cell) , refraining from considering the cell for idle mode reselection of the UE 102, etc.

For example, cell evaluating component 112 can maintain a forbidden cell list 118. Thus, for example, refraining from evaluating the target cell at Block 210 can include adding the cell (e.g., a cell identifier) to the forbidden cell list 118. It is to be appreciated that the forbidden cell list 118 may include a duration of time during which the cell is forbidden from being evaluated, an expiration time after which the cell can be evaluated, a mechanism to remove cells from the forbidden cell list 118 after the duration of time, etc. For example, cell evaluating component 112 can initialize the forbidden cell list 118 to NULL when the UE 102 enters connected mode with the serving cell (e.g., provided by network entity 104) , and/or may clear the forbidden cell list 118 when the UE 102 exits connected mode with the serving cell (or with a related network regardless of the serving cell) . In another example, it is to be appreciated that redirecting component 114 may additionally or alternatively manage the forbidden cell list 118 such that cells may be evaluated by cell evaluating component 112, but redirecting component 114 may not report information (e.g., measurement reports) related to cells in the forbidden cell list 118 to the serving cell as part of initiating the redirection.

In a specific example, the serving RAT can be TD-SCDMA (or WCDMA, GSM, etc. ) . Cell evaluating component 112 can evaluate neighboring cells (e.g., compare signal qualities of the neighboring cells to a threshold) of different RATs for redirection. For example, the UE 102 can be in a PS call or mode with the serving cell, and cell evaluating component 112 can evaluate the neighboring cells for providing enhanced or different data access via a different RAT, such as LTE. Initiating redirection at Block 202 (by redirecting component 114) can include redirecting to a target cell of an LTE RAT based at least in part on cell evaluating component 112 detecting an event 3A in TD-SCDMA. For example, redirecting component 114 can report the event 3A to the network entity 104, which can cause initiation of the redirection. For example, event 3A may relate to detecting that a signal received from a target cell, which may be provided by network entity 106, of a target RAT achieves a threshold signal quality while a signal received from the serving cell, which may be provided by network entity 104, fails to achieve the same or another threshold signal quality. In an example, the target cell can be an LTE cell. For instance, redirecting component 114 can report the event 3A to the network entity 104, which can cause the redirection, or can otherwise request redirection from the network entity 104 based on detecting the event 3A. In either case, network entity 104 can transmit a RRC connection release message to the UE 102 with the frequency reported in the event 3A.

In addition, in this example, redirecting component 114 can determine that one or more parameters associated with the target LTE cell, such as a TA, are in a forbidden list associated with the UE 102 (e.g., a list managed by forbidden list managing component 116) . In an example, redirecting component 114 can determine this based on initiating the redirection to the target LTE cell (which may be provided by network entity 106) based on receiving the RRC connection release message (which may specify the frequency of the target LTE cell) . In addition, for example, communicating component 110 can receive the one or more parameters from the target LTE cell as part of attempting to establish a connection therewith (e.g., in system information, dedicated configuration information, etc. as described) . Accordingly, the UE 102 is not to establish a connection with the target LTE cell based on detecting the one or more parameters in the forbidden list.

In this regard, redirecting component 114 can revert the UE 102 back to the serving cell that utilizes the serving RAT (e.g., TD-SCDMA, which can be provided by network entity 104) . In addition, cell evaluating component 112 can determine to refrain from evaluating the target LTE cell in subsequent evaluations for determining whether to redirect the UE (e.g., while in the PS call or mode) based at least in part on determining the one or more parameters (e.g., the TA, LA, etc. ) are in the forbidden list. Cell evaluating component 112 can refrain from evaluating the target cell in this regard at least for a period of time. Thus, the UE 102 does not ping pong between the serving cell and the target LTE cell. The ping pong may have been caused as the network entity 104 may not have the forbidden list of the UE 102 and does not prevent the ping pong. Additionally, the TD-SCDMA system may not have the LTE forbidden list, and the UE 102 can accordingly keep triggering event 3A. By having the UE 102 manage the redirection in this regard, ping ponging between RATs can be avoided.

FIG. 3 illustrates an example system 300 for managing redirection of a UE between multiple RATs. System 300 includes a UE LTE 302, which may be an LTE stack or other process that manages LTE operations/communications at a UE, a UE TD-SCDMA (TDS) 304, which may be a TDS stack or other process that manages TDS operations/communications at the UE, and a TDS network 306 to which the UE communicates via UE TDS 304. UE LTE 302 can get a TA forbidden list 310. As described, UE LTE 302 may receive the list in a configuration from an LTE network entity, receive the list from a stored configuration, etc., where the TA forbidden list includes one or more TAs related to cells to which the UE is prevented from establishing communications. The UE can be in communications with the TDS network 306, and thus, the UE TDS 304 may establish a PS call with the TDS network (NW) 306, and the UE can determine to configure an LTE cell (not shown) based on measurement control messages from the UE at 312. Accordingly, the UE TDS 304 sends a measurement report (e.g.,

event

3A, 3C, 3D, etc. ) to the TDS network 306. The measurement report may include measurements of one or more LTE cells for consideration in handing over the UE (e.g., to provide improved service for the PS call) .

TDS NW 306 sends an RRC connection release message with redirection information 316 to the UE TDS 304. UE TDS 304 accordingly releases the PS call with TDS NW 306 to search LTE coverage based on the rejection info at 318. UE TDS 304 sends the redirection info 320 to UE LTE 302. Accordingly, UE LTE 302 tries to find LTE coverage based on the redirection info (e.g., on a frequency in the redirection info) but determines that all LTE cell (s) on the frequency advertise a TA in the TA forbidden list at 322. In this example, the UE LTE 302 notifies the UE TDS 304 of the cell (s) having the TA in the TA forbidden list, and to camp on TDS 324. UE LTE 302 may send the notification before UE TDS 304 camps on the TDS network 306 to ensure the UE does not trigger

event

3A, 3C, 3D, etc. based on the LTE cell. UE TDS 304 can find service on the TDS network 306, and can bar the cell (s) for at least N seconds. As described, barring the cell (s) can include refraining from evaluating the cell (s) for

subsequent event

3A, 3C, 3D, etc. detection, refraining from obtaining measurements of the cell (s) , refraining from performing idle mode reselection to the cells, etc. at the UE. In addition, as described, the UE TDS 304 can maintain a list of forbidden cells, and can store information regarding the cell (s) in the list (e.g., identifiers of the cell (s) , a duration of time for which to refrain from evaluating the cell (s) , etc. ) .

FIG. 4 is a conceptual diagram illustrating an example of a hardware implementation for an apparatus 400 employing a processing system 414. In some examples, the processing system 414 may comprise a UE or a component of a UE (e.g., UE 102 or network entity 104/106 of FIG. 1, etc. ) . In this example, the processing system 414 may be implemented with a bus architecture, represented generally by the bus 402. The bus 402 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 414 and the overall design constraints. The bus 402 links together various circuits including one or more processors, represented generally by the processor 404, computer-readable media, represented generally by the computer-readable medium 406, communicating component 110, etc. (see FIG. 1) , which may be configured to carry out one or more methods or procedures described herein.

The bus 402 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art. A bus interface 408 provides an interface between the bus 402 and a transceiver 410. The transceiver 410 provides a means for communicating with various other apparatus over a transmission medium. Depending upon the nature of the apparatus, a user interface 412 (e.g., keypad, display, speaker, microphone, joystick) may also be provided.

The processor 404 is responsible for managing the bus 402 and general processing, including the execution of software stored on the computer-readable medium 406. The software, when executed by the processor 404, causes the processing system 414 to perform the various functions described infra for any particular apparatus. The computer-readable medium 406 may also be used for storing data that is manipulated by the processor 404 when executing software.

In an aspect, processor 404, computer-readable medium 406, or a combination of both may be configured or otherwise specially programmed to perform the functionality of the communicating component 110, components thereof, or various other components described herein to perform functions described herein (e.g., method 200 (FIG. 2) , functions of system 300 (FIG. 3) , etc. ) . For example, processor 404, computer-readable medium 406, or a combination of both may be configured or otherwise specially programmed to perform the functionality of the communicating component 110 described herein to perform functions described herein (e.g., method 200 (FIG. 2) , functions of system 300 (FIG. 3) , etc. ) , and/or the like.

FIG. 5 is a block diagram of a Node B 510 in communication with a UE 550, where the Node B 510 may be the first subscription network entity 104/106 in FIG. 1, and the UE 550 may be the UE 102 of FIG. 1. For example, UE 550 may include communicating component 110 or otherwise configured to perform the functions thereof, as described in relation to FIGs. 1 and 2. For example, UE 550 can manage redirection such to avoid ping ponging between RATs, as described above. The communicating component 110 is shown as connected to controller/processor 590, and can be implemented by or within the controller/processor 590 to provide functions described of the communicating component 110 and/or one or more components thereof (e.g., as described in FIG. 1 and method 200 of FIG. 2, functions of system 300 (FIG. 3) , above) . In other examples, communicating component 110 can be at least partially implemented by other processors, such as a receive processor 570, transmit processor 580, etc. to communicate with a Node B 510 or other network entity, as described above.

In the downlink communication, a transmit processor 520 may receive data from a data source 512 and control signals from a controller/processor 540. The transmit processor 520 provides various signal processing functions for the data and control signals, as well as reference signals (e.g., pilot signals) . For example, the transmit processor 520 may provide cyclic redundancy check (CRC) codes for error detection, coding and interleaving to facilitate forward error correction (FEC) , mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) , and the like) , spreading with orthogonal variable spreading factors (OVSF) , and multiplying with scrambling codes to produce a series of symbols. Channel estimates from a channel processor 544 may be used by a controller/processor 540 to determine the coding, modulation, spreading, and/or scrambling schemes for the transmit processor 520. These channel estimates may be derived from a reference signal transmitted by the UE 550 or from feedback from the UE 550. The symbols generated by the transmit processor 520 are provided to a transmit frame processor 530 to create a frame structure. The transmit frame processor 530 creates this frame structure by multiplexing the symbols with information from the controller/processor 540, resulting in a series of frames. The frames are then provided to a transmitter 532, which provides various signal conditioning functions including amplifying, filtering, and modulating the frames onto a carrier for downlink transmission over the wireless medium through antenna 534. The antenna 534 may include one or more antennas, for example, including beam steering bidirectional adaptive antenna arrays or other similar beam technologies.

At the UE 550, a receiver 554 receives the downlink transmission through an antenna 552 and processes the transmission to recover the information modulated onto the carrier. The information recovered by the receiver 554 is provided to a receive frame processor 560, which parses each frame, and provides information from the frames to a channel processor 594 and the data, control, and reference signals to a receive processor 570. The receive processor 570 then performs the inverse of the processing performed by the transmit processor 520 in the Node B 510. More specifically, the receive processor 570 descrambles and despreads the symbols, and then determines the most likely signal constellation points transmitted by the Node B 510 based on the modulation scheme. These soft decisions may be based on channel estimates computed by the channel processor 594. The soft decisions are then decoded and deinterleaved to recover the data, control, and reference signals. The CRC codes are then checked to determine whether the frames were successfully decoded. The data carried by the successfully decoded frames will then be provided to a data sink 572, which represents applications running in the UE 550 and/or various user interfaces (e.g., display) . Control signals carried by successfully decoded frames will be provided to a controller/processor 590. When frames are unsuccessfully decoded by the receiver processor 570, the controller/processor 590 may also use an acknowledgement (ACK) and/or negative acknowledgement (NACK) protocol to support retransmission requests for those frames.

In the uplink, data from a data source 578 and control signals from the controller/processor 590 are provided to a transmit processor 580. The data source 578 may represent applications running in the UE 550 and various user interfaces (e.g., keyboard) . Similar to the functionality described in connection with the downlink transmission by the Node B 510, the transmit processor 580 provides various signal processing functions including CRC codes, coding and interleaving to facilitate FEC, mapping to signal constellations, spreading with OVSFs, and scrambling to produce a series of symbols. Channel estimates, derived by the channel processor 594 from a reference signal transmitted by the Node B 510 or from feedback contained in the midamble transmitted by the Node B 510, may be used to select the appropriate coding, modulation, spreading, and/or scrambling schemes. The symbols produced by the transmit processor 580 will be provided to a transmit frame processor 582 to create a frame structure. The transmit frame processor 582 creates this frame structure by multiplexing the symbols with information from the controller/processor 590, resulting in a series of frames. The frames are then provided to a transmitter 556, which provides various signal conditioning functions including amplification, filtering, and modulating the frames onto a carrier for uplink transmission over the wireless medium through the antenna 552.

The uplink transmission is processed at the Node B 510 in a manner similar to that described in connection with the receiver function at the UE 550. A receiver 535 receives the uplink transmission through the antenna 534 and processes the transmission to recover the information modulated onto the carrier. The information recovered by the receiver 535 is provided to a receive frame processor 536, which parses each frame, and provides information from the frames to the channel processor 544 and the data, control, and reference signals to a receive processor 538. The receive processor 538 performs the inverse of the processing performed by the transmit processor 580 in the UE 550. The data and control signals carried by the successfully decoded frames may then be provided to a data sink 539 and the controller/processor, respectively. If some of the frames were unsuccessfully decoded by the receive processor, the controller/processor 540 may also use an acknowledgement (ACK) and/or negative acknowledgement (NACK) protocol to support retransmission requests for those frames.

The controller/

processors

540 and 590 may be used to direct the operation at the Node B 510 and the UE 550, respectively. For example, the controller/

processors

540 and 590 may provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The computer readable media of

memories

542 and 592 may store data and software for the Node B 510 and the UE 550, respectively. A scheduler/processor 546 at the Node B 510 may be used to allocate resources to the UEs and schedule downlink and/or uplink transmissions for the UEs.

Several aspects of a telecommunications system have been presented with reference to an HSPA system. As those skilled in the art will readily appreciate, various aspects described herein may be extended to other telecommunication systems, network architectures and communication standards.

In accordance with various aspects, an element, or any portion of an element, or any combination of elements may be implemented with a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, digital signal processors (DSPs) , field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium. The computer-readable medium may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip) , an optical disk (e.g., compact disk (CD) , digital versatile disk (DVD) ) , a smart card, a flash memory device (e.g., card, stick, key drive) , random access memory (RAM) , read only memory (ROM) , programmable ROM (PROM) , erasable PROM (EPROM) , electrically erasable PROM (EEPROM) , a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium may also include, by way of example, a carrier wave, a transmission line, and any other suitable medium for transmitting software and/or instructions that may be accessed and read by a computer. The computer-readable medium may be resident in the processing system, external to the processing system, or distributed across multiple entities including the processing system. The computer-readable medium may be embodied in a computer-program product. By way of example, a computer-program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented herein depending on the particular application and the overall design constraints imposed on the overall system.

It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods or methodologies described herein may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a； b； c； a and b； a and c； b and c； and a, b and c. All structural and functional equivalents to the elements of the various aspects described herein that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112 (f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for. ”

Claims

A method of managing redirection between radio access technologies (RAT) at a user equipment (UE) , comprising:

initiating a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold；

determining, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE；

reverting the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list； and

refraining from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list.
The method of claim 1, wherein the one or more parameters include a location area (LA) or a tracking area (TA) of the target cell.
The method of claim 1, wherein refraining from evaluating the target cell comprises refraining from evaluating the target cell for a period of time, after which the target cell is evaluated in subsequently evaluating cells in determining whether to initiate the subsequent redirection.
The method of claim 3, wherein the period of time is configured by a network entity of the serving RAT.
The method of claim 1, wherein initiating the redirection is performed as part of detecting an event 3A, 3C, or 3D in a time division synchronous code division multiple access (TD-SCDMA) system.
The method of claim 5, wherein the target cell is a long term evolution (LTE) cell.
The method of claim 1, wherein initiating the redirection of the UE is further based at least in part on detecting the serving cell as having a serving signal quality that does not achieve a serving threshold.
The method of claim 1, wherein refraining from evaluating the target cell comprises at least one of refraining from measuring the target cell in subsequently evaluating cells in determining whether to initiate the subsequent redirection, refraining from reporting or a measurement for the target cell in determining whether to initiate the subsequent redirection.
The method of claim 8, wherein at least one of the redirection or the subsequent redirection comprises a connected mode handover or an idle mode reselection from the serving cell to a cell of another RAT.
An apparatus for managing redirection between radio access technologies (RAT) at a user equipment (UE) , comprising:

a redirecting component configured to:

initiate a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold；

determine, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE； and

revert the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list； and

a cell evaluating component configured to refrain from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on the redirecting component determining that the one or more parameters associated with the target cell are in the forbidden list.
The apparatus of claim 10, wherein the one or more parameters include a location area (LA) or a tracking area (TA) of the target cell.
The apparatus of claim 10, wherein the cell evaluating component is configured to refrain from evaluating the target cell comprises for a period of time, after which the cell evaluating component evaluates target cell in subsequently evaluating cells in determining whether to initiate the subsequent redirection.
The apparatus of claim 10, wherein the redirecting component is configured to initiate the redirection as part of detecting an event 3A in a time division synchronous code division multiple access (TD-SCDMA) system.
The apparatus of claim 13, wherein the target cell is a long term evolution (LTE) cell.
The apparatus of claim 10, wherein the redirecting component is configured to initiate the redirection of the UE further based at least in part on detecting the serving cell as having a serving signal quality that does not achieve a serving threshold.
An apparatus for managing redirection between radio access technologies (RAT) at a user equipment (UE) , comprising:

means for initiating a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold；

means for determining, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE；

means for reverting the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list； and

means for refraining from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list.
The apparatus of claim 16, wherein the one or more parameters include a location area (LA) or a tracking area (TA) of the target cell.
The apparatus of claim 16, wherein means for refraining refrains from evaluating the target cell for a period of time, after which the means for refraining evaluates the target cell in subsequently evaluating cells in determining whether to initiate the subsequent redirection.
The apparatus of claim 16, wherein means for initiating initiates the redirection as part of detecting an event 3A in a time division synchronous code division multiple access (TD-SCDMA) system.
The apparatus of claim 19, wherein the target cell is a long term evolution (LTE) cell.
The apparatus of claim 16, wherein the means for initiating initiates the redirection of the UE further based at least in part on detecting the serving cell as having a serving signal quality that does not achieve a serving threshold.
A computer-readable medium comprising code executable by a computer for managing redirection between radio access technologies (RAT) at a user equipment (UE) , the code comprising:

code for initiating a redirection of a UE from a serving cell that utilizes a serving RAT to a target cell that utilizes a RAT other than the serving RAT based at least in part on detecting the target cell as having a target signal quality that achieves a target threshold；

code for determining, as part of the redirection, that one or more parameters associated with the target cell are in a forbidden list related to the UE；

code for reverting the UE to the serving cell based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list； and

code for refraining from evaluating the target cell in subsequently evaluating cells in determining whether to initiate a subsequent redirection, wherein the refraining is based at least in part on determining that the one or more parameters associated with the target cell are in the forbidden list.
The computer-readable medium of claim 22, wherein the one or more parameters include a location area (LA) or a tracking area (TA) of the target cell.
The computer-readable medium of claim 22, wherein code for refraining refrains from evaluating the target cell for a period of time, after which the code for refraining evaluates the target cell in subsequently evaluating cells in determining whether to initiate the subsequent redirection.
The computer-readable medium of claim 22, wherein code for initiating initiates the redirection as part of detecting an event 3A in a time division synchronous code division multiple access (TD-SCDMA) system.
The computer-readable medium of claim 25, wherein the target cell is a long term evolution (LTE) cell.
The computer-readable medium of claim 22, wherein the code for initiating initiates the redirection of the UE further based at least in part on detecting the serving cell as having a serving signal quality that does not achieve a serving threshold.