Patent Application
20140135016
1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to network selection based on user preferences.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.
According to 3GPP specifications, such as, but not limited to the 3GPP TS 25.304 specification, which is incorporated herein by reference, in addition to traditional cell reselection, a user equipment (UE) should use an autonomous search function (ASF) to search for closed subscriber group (CSG) cells when at least one CSG ID with an associated public land mobile network (PLMN) identity is included in the UE's allowed CSG list. This UE autonomous search for CSG cells may also include CSG cells of communication technologies (e.g., radio access technologies (RATs)) other than those employed by a serving mobile network, or UTRAN. Furthermore, according to the specifications, the UE is required to perform the autonomous search function in Idle, Cell_PCH and URA_PCH states and the UE should disable the autonomous search function for CSG cells if the UE's allowed CSG list is empty.
The specification does not mandate, however, when and where the UE shall start the ASF—thus, this is left for UE implementation. In legacy cases, CSG cells are not always broadcasted in the system information blocks transmitted by the CSG cells; and for that reason, the UE must often perform exhaustive searches for the discovery of CSG cells. Unfortunately, such exhaustive searches require a nontrivial amount of battery power.
Therefore, methods and apparatuses for improved cell association fingerprinting are needed, such as those that limit the occurrence of exhaustive autonomous search functions so that they are only executed when necessary.
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 accordance with one or more aspects and corresponding disclosure thereof, various aspects are described in connection with maintaining a cell database for wireless communications.
In an aspect, a method of maintaining a cell database for wireless communications includes discovering a second cell to which a user equipment may reselect, wherein the user equipment is currently served by a first cell, and the second cell is a closed subscriber group cell. The method further includes querying a fingerprinting database determine whether the second cell was previously recorded in the fingerprinting database. Additionally, the method includes, upon determining that the second cell was not previously recorded, adding the second cell to the fingerprinting database. The adding of the second cell to the fingerprinting database may include indicating an association between the first cell and the second cell in the fingerprinting database.
In an aspect, a computer-program product comprising a non-transitory computer-readable medium may include code for causing a computer to discover a second cell to which a user equipment may reselect, wherein the user equipment may be currently served by a first cell and the second cell is a closed subscriber group cell. The computer-readable medium may include code for causing a computer to query a fingerprinting database to determine whether the second cell was previously recorded in the fingerprinting database. Upon determining that the second cell was not previously recorded, the computer-readable medium may include code for causing a computer to add the second cell to the fingerprinting database. Adding the second cell may include indicating an association between the first cell and the second cell in the fingerprinting database.
In an aspect, an apparatus for maintaining a cell database for wireless communications may include means for discovering a second cell to which a user equipment may reselect, wherein the user equipment may be currently served by a first cell and the second cell is a closed subscriber group cell. The apparatus may include means for querying a fingerprinting database to determine whether the second cell was previously recorded in the fingerprinting database. Upon determining that the second cell was not previously recorded, the apparatus may include means for adding the second cell to the fingerprinting database. Adding the second cell may include indicating an association between the first cell and the second cell in the fingerprinting database.
In an aspect, an apparatus for maintaining a cell database for wireless communications may include a reselection component for discovering a second cell to which a user equipment may reselect, wherein the user equipment may be currently served by a first cell and the second cell is a closed subscriber group cell. The apparatus may include a fingerprinting database querying component for querying a fingerprinting database to determine whether the second cell was previously recorded in the fingerprinting database. The apparatus may include a fingerprinting manager for, upon determining that the second cell was not previously recorded, adding the second cell to the fingerprinting database. Adding the second cell may include indicating an association between the first cell and the second cell in the fingerprinting database.
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.
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 structures and components are shown in block diagram form in order to avoid obscuring such concepts.
The present disclosure provides methods and apparatuses for maintaining associations between wireless cells serving one or more user equipment (UE) by maintaining a fingerprinting database. Thus, in an aspect, the present disclosure presents methods of maintaining cell associations such that where a particular cell is associated with one or more other cells in some way, one or more of the cells may be fingerprinted to the other cell or cells.
For example, in an aspect, the first time that a UE reselects its serving cell from a first cell to a second cell, a fingerprinting manager or fingerprinting component at the UE and/or one or more of the network entities (e.g., NodeB, eNodeB, base station, femtocell, picocell, or other wireless cell serving device) may create or update one or more elements associated with the first and/or second cell in a fingerprinting database. In another example, the UE, currently camped on a first cell, may discover a second cell to which the UE may successfully reselect in the future. The second cell may be discovered through, for example, the UE's local search and measurement outcome. In response to the discovery of the second cell, and not necessarily the UE reselecting to the second cell from the first cell, the fingerprinting manager or fingerprinting component at the UE and/or one or more of the network entities may create or update one or more elements associated with the first and/or second cell in a fingerprinting database. In an aspect, the one or more elements may include an identifier corresponding to the first cell and/or second cell. In some examples, this identifier may comprise the cell Public Land Mobile Network (PLMN), Absolute Radio Frequency Channel Number (ARFCN), and/or its cell identification number.
Furthermore, the first cell may be a macro cell (e.g., a cellular network cell and/or sector), though the first cell may also be any other wireless cell (e.g., a picocell, femtocell, WiFi cell, or the like). Additionally, the first cell and second cell may operate according to different communication technologies, such as, but not limited to, GSM, WCDMA, and/or LTE. In addition, the second cell may be a closed subscriber group (CSG) cell, and may be a picocell, femtocell, WiFi cell, or the like (though the second cell may be a macro cell or larger wireless network serving cell as well).
In an additional aspect, a neighbor cell list of the second cell may be fingerprinted to the second cell. The neighbor cell list may be obtained either from the network associated with the first cell or the second cell, from the UE's local search and measurement outcome when camped on the first cell before reselection, and/or the second cell after reselection. Alternatively or additionally, the neighbor cell list of the second cell can also be fingerprinted to the first cell (and/or vice versa). Again, this neighbor list may be obtained either from the network or from the UE's local search and measurement outcome after the UE has camped on the second cell, though it may be obtained from another source at the UE and/or the first or second cells. Additionally, the second cell, which may be one or more CSG cells, may be identified by its PLMN, Absolute Radio Frequency Channel Number (ARFCN), cell identification number, the CSG ID, and/or a homeNodeB name (HNB).
In an additional aspect of the present disclosure, where an association between two or more cells is established (e.g., a fingerprint entry associating the two cells), for example, at cell discovery or reselection, the UE and/or one or more of the first and second cells may create or update a timestamp of the association or fingerprint. This timestamp may allow the fingerprinting database entries to be updated after expiration of a timer. For example, where such a timer expires without the occurrence of a subsequent association or fingerprinting update, the UE and/or the first or second cell may remove the association between the cells.
Thus, where a UE reselects its serving cell from a first cell to a second cell, the UE may query a fingerprinting database to determine whether the second cell is an existing entry in the fingerprinting database. If no such entry exists, the second cell, the first cell, and/or an association between the cells may be added and/or timestamped. Alternatively, where such an entry already exists (i.e., was previously entered), then the UE may check whether the associated cell is an existing entry in the database. In another example, the UE may query the fingerprinting database in response to the UE discovering a second cell to which it may reselect from a first cell.
Additionally, if a cell in the database (e.g., second cell) has not been detected as associated with another cell in the database (e.g., first cell) after a certain amount of time, which may be tracked using one or more timers, then the UE can deem that fingerprint as out-of-date, and can remove or delete the fingerprint or association between the cells from the fingerprinting database. Furthermore, if the second cell only has one fingerprint (the first cell) upon expiry of a timer, then the second cell may also be removed or deleted from the database. In another aspect, a counter may be used by the UE to maintain a record of information about a cell and, if the counter reaches a threshold value, the UE may determine the cell to be out-of-date, and delete an entry associated with the cell in the fingerprinting database. For example, the counter may track a number of times the cell was discovered by the UE without a successful reselection to the cell by the UE.
Thus, by implementing the procedures outlined above and further described below, the UE may perform a limited cell search guided by the fingerprinting database, for instance, to find CSG cells associated with a currently serving cell, rather than performing a battery-draining traditional autonomous search function.
Referring to
In some examples, wireless communication between UE 10 and the cells may occur on one or more wireless links 14 and/or 18. In a further aspect, first cell 12 and/or second cell 16 may have an associated network component, such as an access point, including a base station (BS) or NodeB, a relay, a peer-to-peer device, a radio network controller (RNC), an authentication, authorization and accounting (AAA) server, a mobile switching center (MSC), picocell, piconode, femtocell, femtonode, WiFi access point, etc., that can enable UE 10 to communicate and/or that can establish and maintain a communication link, such as wireless links 14 and/or 18. In addition, UE 10 may be a multimode device, which may allow the UE to communicate with multiple technology type networks.
In addition, for purposes of the present disclosure the communication technology used for communication between one or more of UE 10, first cell 12, and second cell 16 may be of a 3G technology type, such as, but not limited to, data optimized (DO), WCDMA, Time Division Synchronous Code Division Multiple Access (TDS-CDMA), or any other third-generation mobile communications technology. Additionally, in some examples, the communication technology may be a 2G technology type, such as, but not limited to, GSM, GPRS, or EDGE. Furthermore, example RAT types may include more advanced RATs, such as, but not limited to, Long-Term Evolution (LTE), Time-Division Long-Term Evolution (TD-LTE), or any other fourth-generation mobile communications technology. Alternatively or additionally, any other communication technology type may be used for such communication.
Furthermore, UE 10 may include a fingerprinting manager 102, which may be configured to manage a fingerprinting database 108 that may store associations between one or more serving cells (e.g., first cell 12 and/or second cell 16). In an aspect, the fingerprinting manager 102 may alternatively or additionally be located at and/or maintained, by a network entity, such as a network entity associated with first cell 12 and/or second cell 16. In addition, fingerprinting manager 102 may include a reselection component 104, which may be configured to manage serving cell reselection for UE 10 (or one or more served UEs if fingerprinting manager 102 is located at a cell). In an aspect, reselection component 104 may periodically perform ASF or otherwise scan for pilot or beacon signals in an attempt to discover one or more cells not currently serving the UE. Alternatively or additionally, reselection component 104 may query a fingerprinting database 108 to determine whether one or more cells 110 are associated with a cell currently serving the UE, and if so, may limit its scan to one or more frequencies or channels associated with the one or more associated cells.
Alternatively, a fingerprinting database querying component 106, which may be associated with fingerprinting manager 102, may perform the fingerprinting database query. Furthermore, fingerprinting database querying component 106 may be configured to query fingerprinting database 108 to determine whether a cell newly discovered by reselection component 104 has been previously entered into the fingerprinting database 108.
In addition, as introduced above, fingerprinting manager 102 may include a fingerprinting database 108, which may be configured to store information related to one or more cells(s) 110. In an aspect, such information may include cell identifier(s) 116 that may include, but are not limited to, a PLMN, an Absolute Radio Frequency Channel Number (ARFCN), a cell identification number, a CSG ID, a HNB name, and/or any other cell identifying information. Furthermore, each cell 110 may include a list of one or more associated cells 112, which may also be identified by the above-mentioned identifying information or cell identifiers 116.
In an aspect, the list of one or more associated cells 112 may include a neighbor cell list of each cell 110 that is fingerprinted to each cell 110. This list may be obtained from the network associated with each cell 110, a network associated with the neighbor cells, directly from the neighbor cells, or from the UE's local search and measurement outcome when camped on the first cell before discovery or reselection and/or the second cell after discovery or reselection, though it may be obtained from another source at the UE and/or one of the cells 110. Additionally, the cells in the neighbor cell list may be one or more CSG cells, and may be identified by their PLMN, Absolute Radio Frequency Channel Number (ARFCN), cell identification number, the CSG ID, and/or a homeNodeB name (HNB).
Additionally, fingerprinting database 108 may include one or more timestamps 114 that may correspond to each cell 110 and any associated cells 112. In an aspect, fingerprinting database 108 may be configured to create and store a timestamp 114 when reselection component 104 discovers a cell, enters or updates that cell in an entry in fingerprinting database 108, and/or reselects the serving cell of UE 10 to the newly discovered cell. Furthermore, in an aspect, timer manager 118 may start a timer upon the creation of the timestamp. In addition, timer manager 118 may be configured to monitor each timer such that, for example, if an association between a first cell and a second cell (e.g., first cell 12 and second cell 16) is not reported or otherwise updated before the expiration of the timer, one or both of the first cell and second cell (or an indication of the association or fingerprint between the cells) may be determined to be out-of-date and discarded from the fingerprinting database 108. In another aspect, a counter may be used by the UE to maintain a record of information about a cell and, if the counter reaches a threshold value, the UE may determine the cell to be out-of-date, and delete an entry associated with the cell in the fingerprinting database. For example, the counter may track a number of times the cell was discovered by the UE without a successful reselection to the cell by the UE.
Referring to
Computer device 200 further includes a memory 204, such as for storing data used herein and/or local versions of applications being executed by processor 202. Memory 204 can include any type of memory usable by a computer, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof
Further, computer device 200 includes a communications component 206 that provides for establishing and maintaining communications with one or more parties utilizing hardware, software, and services as described herein. Communications component 206 may carry communications between components on computer device 200, as well as between computer device 200 and external devices, such as devices located across a communications network and/or devices serially or locally connected to computer device 200. For example, communications component 206 may include one or more buses, and may further include transmit chain components and receive chain components associated with a transmitter and receiver, respectively, or a transceiver, operable for interfacing with external devices. In an additional aspect, communications component 206 may be configured to receive one or more pages and/or page indicators from one or more subscriber networks. In a further aspect, such a page or page indicator may correspond to the second subscription and may be received via the first communication technology type communication services.
Additionally, computer device 200 may further include a data store 208, which can be any suitable combination of hardware and/or software, that provides for mass storage of information, databases, and programs employed in connection with aspects described herein. For example, data store 208 may be a data repository for applications not currently being executed by processor 202.
Computer device 200 may additionally include a user interface component 210 operable to receive inputs from a user of computer device 200, and further operable to generate outputs for presentation to the user. User interface component 210 may include one or more input devices, including but not limited to a keyboard, a number pad, a mouse, a touch-sensitive display, a navigation key, a function key, a microphone, a voice recognition component, any other mechanism capable of receiving an input from a user, or any combination thereof Further, user interface component 210 may include one or more output devices, including but not limited to a display, a speaker, a haptic feedback mechanism, a printer, any other mechanism capable of presenting an output to a user, or any combination thereof In an additional aspect, a user using the user interface 210 may set one of a first subscription or a second subscription as a dedicated data service (DDS) for the computer device 200.
In a mobile station implementation, such as for UE 10 of
Referring to
In an aspect, at block 30, a UE (e.g., UE 10,
In an additional optional aspect of methodology 3 (this and below optional aspects not shown), the UE may start a timer upon discovery (or reselection) and/or storing/updating the second cell identifier(s) or the association between the first cell and the second cell in the fingerprinting database. In an aspect, the timer may be set based on a predetermined period of time. The predetermined period of time may be determined to have expired based on a timestamp and a current time reading. If the timer elapses, e.g., the predetermined period of time has expired, before the UE again updates the association and/or cell identifier, the UE may determine that the fingerprint of the second cell, e.g., the association between the first cell and the second cell in the fingerprinting database, is out-of-date. As a result, the UE may remove or delete one or more of the first and second cell entries in the fingerprinting database. Additionally or alternatively, the UE may delete a first cell entry in the fingerprinting database when the UE determines that the first cell is only associated with the second cell, upon removal of the second cell from the fingerprinting database.
In an aspect, a counter may be used by the UE to maintain a record of information about a cell and, if the counter reaches a threshold value, the UE may determine the cell to be out-of-date, and delete an entry associated with the cell in the fingerprinting database. For example, the counter may track a number of times the cell was discovered by the UE without a successful reselection to the cell by the UE.
Referring to
Additionally, system 4 can include a memory 49 that retains instructions for executing functions associated with the electrical components 42, 44, 46, and 48, and/or stores data used or obtained by the electrical components 42, 44, 46, and 48. While shown as being external to memory 49, it is to be understood that one or more of the electrical components 42, 44, 46, and 48 can exist within memory 49. In one example, electrical components 42, 44, 46, and 48 can comprise at least one processor, or each electrical component 42, 44, 46, and 48 can be a corresponding module of at least one processor. Moreover, in an additional or alternative example, electrical components 42, 44, 46, and 48 can be a computer program product including a computer readable medium, where each electrical component 42, 44, 46, and 48 can be corresponding code.
The processor 504 is responsible for managing the bus 502 and general processing, including the execution of software stored on the computer-readable medium 506. The software, when executed by the processor 504, causes the processing system 514 to perform the various functions described above for any particular apparatus. The computer-readable medium 506 may also be used for storing data that is manipulated by the processor 504 when executing software.
The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. By way of example and without limitation, the aspects of the present disclosure illustrated in
Communication between a UE 610 and a NodeB 608 may be considered as including a physical (PHY) layer and a medium access control (MAC) layer. Further, communication between a UE 610 and an RNC 606 by way of a respective NodeB 608 may be considered as including a radio resource control (RRC) layer. In the instant specification, the PHY layer may be considered layer 1; the MAC layer may be considered layer 6; and the RRC layer may be considered layer 3. Information hereinbelow utilizes terminology introduced in the RRC Protocol Specification, 3GPP TS 65.331 v9.1.0, incorporated herein by reference.
The geographic region covered by the RNS 607 may be divided into a number of cells, with a radio transceiver apparatus serving each cell. A radio transceiver apparatus is commonly referred to as a NodeB in UMTS applications, but may also be referred to by those skilled in the art as a base station (BS), a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), or some other suitable terminology. For clarity, three Node Bs 608 are shown in each RNS 607; however, the RNSs 607 may include any number of wireless Node Bs. The Node Bs 608 provide wireless access points to a CN 604 for any number of mobile apparatuses. Examples of a mobile apparatus include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a notebook, a netbook, a smartbook, a personal digital assistant (PDA), a satellite radio, a global positioning system (GPS) device, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, or any other similar functioning device. The mobile apparatus is commonly referred to as a UE in UMTS applications, but 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 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 a UMTS system, the UE 610 may further include a universal subscriber identity module (USIM) 611, which contains a user's subscription information to a network. For illustrative purposes, one UE 610 is shown in communication with a number of the Node Bs 608. The DL, also called the forward link, refers to the communication link from a NodeB 608 to a UE 610, and the UL, also called the reverse link, refers to the communication link from a UE 610 to a NodeB 608.
The CN 604 interfaces with one or more access networks, such as the UTRAN 602. As shown, the CN 604 is a GSM core network. However, as those skilled in the art will recognize, the various concepts presented throughout this disclosure may be implemented in a RAN, or other suitable access network, to provide UEs with access to types of CNs other than GSM networks.
The CN 604 includes a circuit-switched (CS) domain and a packet-switched (PS) domain. Some of the circuit-switched elements are a Mobile services Switching Centre (MSC), a Visitor location register (VLR) and a Gateway MSC. Packet-switched elements include a Serving GPRS Support Node (SGSN) and a Gateway GPRS Support Node (GGSN). Some network elements, like EIR, HLR, VLR and AuC may be shared by both of the circuit-switched and packet-switched domains. In the illustrated example, the CN 604 supports circuit-switched services with a MSC 612 and a GMSC 614. In some applications, the GMSC 614 may be referred to as a media gateway (MGW). One or more RNCs, such as the RNC 606, may be connected to the MSC 612. The MSC 612 is an apparatus that controls call setup, call routing, and UE mobility functions. The MSC 612 also includes a VLR that contains subscriber-related information for the duration that a UE is in the coverage area of the MSC 612. The GMSC 614 provides a gateway through the MSC 612 for the UE to access a circuit-switched network 616. The GMSC 614 includes a home location register (HLR) 615 containing subscriber data, such as the data reflecting the details of the services to which a particular user has subscribed. The HLR is also associated with an authentication center (AuC) that contains subscriber-specific authentication data. When a call is received for a particular UE, the GMSC 614 queries the HLR 615 to determine the UE's location and forwards the call to the particular MSC serving that location.
The CN 604 also supports packet-data services with a serving GPRS support node (SGSN) 618 and a gateway GPRS support node (GGSN) 620. GPRS, which stands for General Packet Radio Service, is designed to provide packet-data services at speeds higher than those available with standard circuit-switched data services. The GGSN 620 provides a connection for the UTRAN 602 to a packet-based network 622. The packet-based network 622 may be the Internet, a private data network, or some other suitable packet-based network. The primary function of the GGSN 620 is to provide the UEs 610 with packet-based network connectivity. Data packets may be transferred between the GGSN 620 and the UEs 610 through the SGSN 618, which performs primarily the same functions in the packet-based domain as the MSC 612 performs in the circuit-switched domain.
An air interface for UMTS may utilize a spread spectrum Direct-Sequence Code Division Multiple Access (DS-CDMA) system. The spread spectrum DS-CDMA spreads user data through multiplication by a sequence of pseudorandom bits called chips. The “wideband” W-CDMA air interface for UMTS is based on such direct sequence spread spectrum technology and additionally calls for a frequency division duplexing (FDD). FDD uses a different carrier frequency for the UL and DL between a NodeB 608 and a UE 610. Another air interface for UMTS that utilizes DS-CDMA, and uses time division duplexing (TDD), is the TD-SCDMA air interface. Those skilled in the art will recognize that although various examples described herein may refer to a W-CDMA air interface, the underlying principles may be equally applicable to a TD-SCDMA air interface.
An HSPA air interface includes a series of enhancements to the 3G/W-CDMA air interface, facilitating greater throughput and reduced latency. Among other modifications over prior releases, HSPA utilizes hybrid automatic repeat request (HARQ), shared channel transmission, and adaptive modulation and coding. The standards that define HSPA include HSDPA (high speed downlink packet access) and HSUPA (high speed uplink packet access, also referred to as enhanced uplink, or EUL).
HSDPA utilizes as its transport channel the high-speed downlink shared channel (HS-DSCH). The HS-DSCH is implemented by three physical channels: the high-speed physical downlink shared channel (HS-PDSCH), the high-speed shared control channel (HS-SCCH), and the high-speed dedicated physical control channel (HS-DPCCH).
Among these physical channels, the HS-DPCCH carries the HARQ ACK/NACK signaling on the uplink to indicate whether a corresponding packet transmission was decoded successfully. That is, with respect to the downlink, the UE 610 provides feedback to the node B 608 over the HS-DPCCH to indicate whether it correctly decoded a packet on the downlink.
HS-DPCCH further includes feedback signaling from the UE 610 to assist the node B 608 in taking the right decision in terms of modulation and coding scheme and precoding weight selection, this feedback signaling including the CQI and PCI.
“HSPA Evolved” or HSPA+ is an evolution of the HSPA standard that includes MIMO and 64-QAM, enabling increased throughput and higher performance. That is, in an aspect of the disclosure, the node B 608 and/or the UE 610 may have multiple antennas supporting MIMO technology. The use of MIMO technology enables the node B 608 to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity.
Multiple Input Multiple Output (MIMO) is a term generally used to refer to multi-antenna technology, that is, multiple transmit antennas (multiple inputs to the channel) and multiple receive antennas (multiple outputs from the channel). MIMO systems generally enhance data transmission performance, enabling diversity gains to reduce multipath fading and increase transmission quality, and spatial multiplexing gains to increase data throughput.
Spatial multiplexing may be used to transmit different streams of data simultaneously on the same frequency. The data steams may be transmitted to a single UE 610 to increase the data rate or to multiple UEs 610 to increase the overall system capacity. This is achieved by spatially precoding each data stream and then transmitting each spatially precoded stream through a different transmit antenna on the downlink. The spatially precoded data streams arrive at the UE(s) 610 with different spatial signatures, which enables each of the UE(s) 610 to recover the one or more the data streams destined for that UE 610. On the uplink, each UE 610 may transmit one or more spatially precoded data streams, which enables the node B 608 to identify the source of each spatially precoded data stream.
Spatial multiplexing may be used when channel conditions are good. When channel conditions are less favorable, beamforming may be used to focus the transmission energy in one or more directions, or to improve transmission based on characteristics of the channel. This may be achieved by spatially precoding a data stream for transmission through multiple antennas. To achieve good coverage at the edges of the cell, a single stream beamforming transmission may be used in combination with transmit diversity.
Generally, for MIMO systems utilizing n transmit antennas, n transport blocks may be transmitted simultaneously over the same carrier utilizing the same channelization code. Note that the different transport blocks sent over the n transmit antennas may have the same or different modulation and coding schemes from one another.
On the other hand, Single Input Multiple Output (SIMO) generally refers to a system utilizing a single transmit antenna (a single input to the channel) and multiple receive antennas (multiple outputs from the channel). Thus, in a SIMO system, a single transport block is sent over the respective carrier.
Referring to
In one example, UE 734 may be the UE 610 of
As the UE 734 moves from the illustrated location in cell 704 into cell 706, a serving cell change (SCC) or handover may occur in which communication with the UE 734 transitions from the cell 704, which may be referred to as the source cell, to cell 706, which may be referred to as the target cell. Management of the handover procedure may take place at the UE 734, at the Node Bs corresponding to the respective cells, at a radio network controller 606 (
The modulation and multiple access scheme employed by the access network 700 may vary depending on the particular telecommunications standard being deployed. By way of example, the standard may include Evolution-Data Optimized (EV-DO) or Ultra Mobile Broadband (UMB). EV-DO and UMB are air interface standards promulgated by the 3rd Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards and employs CDMA to provide broadband Internet access to mobile stations. The standard may alternately be Universal Terrestrial Radio Access (UTRA) employing Wideband-CDMA (W-CDMA) and other variants of CDMA, such as TD-SCDMA; Global System for Mobile Communications (GSM) employing TDMA; and Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE, LTE Advanced, and GSM are described in documents from the 3GPP organization. CDMA2000 and UMB are described in documents from the 3GPP2 organization. The actual wireless communication standard and the multiple access technology employed will depend on the specific application and the overall design constraints imposed on the system.
The radio protocol architecture may take on various forms depending on the particular application. An example for an HSPA system will now be presented with reference to
Turning to
In the user plane, the L2 layer 808 includes a media access control (MAC) sublayer 810, a radio link control (RLC) sublayer 812, and a packet data convergence protocol (PDCP) 814 sublayer, which are terminated at the node B on the network side. Although not shown, the UE may have several upper layers above the L2 layer 808 including a network layer (e.g., IP layer) that is terminated at a PDN gateway on the network side, and an application layer that is terminated at the other end of the connection (e.g., far end UE, server, etc.).
The PDCP sublayer 814 provides multiplexing between different radio bearers and logical channels. The PDCP sublayer 814 also provides header compression for upper layer data packets to reduce radio transmission overhead, security by ciphering the data packets, and handover support for UEs between NodeBs. The RLC sublayer 812 provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to hybrid automatic repeat request (HARQ). The MAC sublayer 810 provides multiplexing between logical and transport channels. The MAC sublayer 810 is also responsible for allocating the various radio resources (e.g., resource blocks) in one cell among the UEs. The MAC sublayer 810 is also responsible for HARQ operations.
At the UE 950, a receiver 954 receives the downlink transmission through an antenna 952 and processes the transmission to recover the information modulated onto the carrier. The information recovered by the receiver 954 is provided to a receive frame processor 960, which parses each frame, and provides information from the frames to a channel processor 994 and the data, control, and reference signals to a receive processor 970. The receive processor 970 then performs the inverse of the processing performed by the transmit processor 920 in the NodeB 910. More specifically, the receive processor 970 descrambles and despreads the symbols, and then determines the most likely signal constellation points transmitted by the NodeB 910 based on the modulation scheme. These soft decisions may be based on channel estimates computed by the channel processor 994. 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 972, which represents applications running in the UE 950 and/or various user interfaces (e.g., display). Control signals carried by successfully decoded frames will be provided to a controller/processor 990. When frames are unsuccessfully decoded by the receiver processor 970, the controller/processor 990 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 978 and control signals from the controller/processor 990 are provided to a transmit processor 980. The data source 978 may represent applications running in the UE 950 and various user interfaces (e.g., keyboard). Similar to the functionality described in connection with the downlink transmission by the NodeB 910, the transmit processor 980 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 994 from a reference signal transmitted by the NodeB 910 or from feedback contained in the midamble transmitted by the NodeB 910, may be used to select the appropriate coding, modulation, spreading, and/or scrambling schemes. The symbols produced by the transmit processor 980 will be provided to a transmit frame processor 982 to create a frame structure. The transmit frame processor 982 creates this frame structure by multiplexing the symbols with information from the controller/processor 990, resulting in a series of frames. The frames are then provided to a transmitter 956, 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 952.
The uplink transmission is processed at the NodeB 910 in a manner similar to that described in connection with the receiver function at the UE 950. A receiver 935 receives the uplink transmission through the antenna 934 and processes the transmission to recover the information modulated onto the carrier. The information recovered by the receiver 935 is provided to a receive frame processor 936, which parses each frame, and provides information from the frames to the channel processor 944 and the data, control, and reference signals to a receive processor 938. The receive processor 938 performs the inverse of the processing performed by the transmit processor 980 in the UE 950. The data and control signals carried by the successfully decoded frames may then be provided to a data sink 939 and the controller/processor, respectively. If some of the frames were unsuccessfully decoded by the receive processor, the controller/processor 940 may also use an acknowledgement (ACK) and/or negative acknowledgement (NACK) protocol to support retransmission requests for those frames.
The controller/processors 940 and 990 may be used to direct the operation at the NodeB 910 and the UE 950, respectively. For example, the controller/processors 940 and 990 may provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The computer readable media of memories 942 and 992 may store data and software for the NodeB 910 and the UE 950, respectively. A scheduler/processor 946 at the NodeB 910 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 a W-CDMA system. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures and communication standards.
By way of example, various aspects may be extended to other UMTS systems such as TD-SCDMA, High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+) and 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), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems. 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.
In accordance with various aspects of the disclosure, 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 this disclosure. 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 throughout this disclosure 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 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 throughout this disclosure 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, sixth paragraph, 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.”
The present Application for Patent claims priority to Provisional Application No. 61/724,830 entitled “METHOD AND APPARATUS FOR OPTIMIZING THE FREQUENCY OF AUTONOMOUS SEARCH FUNCTIONS FOR DISCOVERING CSG CELLS” filed Nov. 9, 2012, and assigned to the assignee hereof and hereby expressly incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61724830 | Nov 2012 | US |
