HK1141924A - Methods and apparatus for neighbor discovery of base stations in a communication system - Google Patents

Description

Method and apparatus for neighbor discovery of base stations in a communication system

Claiming priority based on 35U.S.C. § 119

This patent application claims priority from a provisional application No.60/944,711 entitled "new basic OF basic properties IN a cosmetic NETWORK", filed on 18.6.2007, assigned to the assignee OF the present application and hereby expressly incorporated herein by reference.

Technical Field

The present disclosure relates generally to methods and apparatus for neighbor discovery of base stations in a communication system, and more particularly to automatic neighbor discovery by base stations with access terminals.

Background

In a communication system, such as a wireless communication system, a base station serving communication content may maintain data about neighboring base stations in the communication system. Neighboring base stations are those base stations geographically disposed relative to a particular base station that represent viable candidate base stations to which a mobile communication device currently served by the particular base station may handoff to when the mobile communication device changes location.

In some wireless communication systems, for example, they use Ultra Mobile Broadband (UMB) technology with Evolved Packet System (EPS) or LTE (long term evolution), a base station may use a communication network linking the base stations to transmit corresponding information to other base stations in the network, for example, evolved base stations (eBS) in a converged access network, such as a Radio Area Network (RAN), connected via an Access Gateway (AGW). In addition, in such systems, when an Access Terminal (AT) performs a handoff from one base station to another, the AT will report neighbor base station information (e.g., pilot ID) AT the time of the handoff, which saves overhead resources. In general, the identification information is sufficient for handover in the network if the handover base station is aware of network neighboring base stations. However, these conventional systems require the operator to manually reconfigure all affected base stations each time a new base station is added to or removed from the RAN, which becomes particularly cumbersome, making acquisition uneconomical and less uniform, especially if temporary base stations are used in the network.

Disclosure of Invention

According to one aspect, a method of discovering a first base station by a second base station in a communication system is disclosed. The method comprises the following steps: in accordance with detection by an access terminal of an identification signal from the first base station in the communication system, receiving a first message from the access terminal to assist the access terminal in handing over from the second base station to the first base station. The method further comprises the following steps: determining whether the first base station is a known base station from the identification signal, and, upon determining that the first base station is not a known base station, transmitting a second message to the access terminal requesting a network identification of the first base station. The method further comprises the following steps: receiving a third message from the access terminal in response to the second message containing the network identification of the first base station, and sending a request for identification data to the first base station in accordance with the network identification.

According to another aspect, an apparatus for discovering a base station in a communication network is disclosed. The apparatus includes a transceiver circuit configured to receive a first message from an access terminal to assist the access terminal in handing over from the second base station to the first base station based on detection by the access terminal of an identification signal from the first base station in the communication system. The device further comprises: a neighbor discovery module to determine from the identification signal whether the first base station is a known base station, wherein the transceiver circuitry is to transmit a second message to the access terminal requesting a network identification of the first base station when it is determined that the first base station is not a known base station, and to receive a third message from the access terminal containing the network identification of the first base station in response to the second message; and a network interface circuit for sending a request for identification data to the first base station via a network link in accordance with the network identification.

According to another aspect, an apparatus for use in a communication system is disclosed, comprising: means for receiving a first message from an access terminal to assist the access terminal in handing over from the second base station to the first base station based on detection by the access terminal of an identification signal from the first base station in the communication system. The device further comprises: means for determining whether the first base station is a known base station based on the identification signal; means for transmitting a second message to the access terminal requesting a network identification of the first base station when it is determined that the first base station is not a known base station. In addition, the apparatus comprises: means for receiving a third message from the access terminal in response to the second message containing the network identification of the first base station; and means for sending a request for identification data to the first base station in accordance with the network identification.

According to another aspect, a computer program product comprising a computer readable medium is disclosed. The medium includes: code for causing a computer to receive a first message from an access terminal to assist the access terminal in handing over from the second base station to the first base station based on detection by the access terminal of an identification signal from the first base station in the communication system. The medium further includes: code for causing a computer to determine whether the first base station is a known base station based on the identification signal; and code for causing a computer to transmit a second message to the access terminal requesting a network identification of the first base station when it is determined that the first base station is not a known base station. The medium further includes: code for causing a computer to receive, from the access terminal, a third message containing the network identification of the first base station in response to the second message; and code for causing a computer to transmit a request for identification data to the first base station in accordance with the network identification.

According to another aspect, a method of discovering a base station in a communication system is disclosed. The method comprises the following steps: detecting, at an access terminal, an identification signal from a first base station in a communication network; and sending a request to a second base station to assist the access terminal in handing over to the first base station in accordance with the identification signal. The method further comprises the following steps: receiving a message requesting identification data of the first base station from the second base station when the second base station determines that the first base station is not a known base station; obtaining the identification data from the first base station and transmitting the identification data to the second base station.

According to another aspect, an apparatus in an access terminal for neighbor discovery of a base station in a communication system is disclosed. The device comprises: transceiver circuitry to detect, at an access terminal, an identification signal from a first base station in a communication network, to send a request to a second base station to assist the access terminal in handing over to the first base station based on the identification signal, and to receive a message from the second base station requesting identification data of the first base station when the second base station determines that the first base station is not a known base station. The device further comprises: a neighbor discovery module for obtaining the identification data from the first base station; and instructing the transceiver circuitry to transmit the identification data to the second base station.

According to another aspect, an apparatus in an access terminal for neighbor discovery of a base station in a communication system is disclosed. The device comprises: means for detecting, at an access terminal, an identification signal from a first base station in a communication network; and means for sending a request to a second base station to assist the access terminal in handing over to the first base station based on the identification signal. The device further comprises: means for receiving a message from the second base station requesting identification data of the first base station when the second base station determines that the first base station is not a known base station; means for obtaining the identification data from the first base station; and means for transmitting the identification data to the second base station.

According to another aspect, a computer program product comprising a computer readable medium is disclosed. The medium includes: code for causing a computer to detect, at an access terminal, an identification signal from a first base station in a communication network; code for causing a computer to transmit a request to a second base station to assist the access terminal in handing over to the first base station in accordance with the identification signal; and code for causing a computer to receive a message from the second base station requesting identification data of the first base station when the second base station determines that the first base station is not a known base station. The medium further includes: code for causing a computer to obtain the identification data from the first base station; and code for causing a computer to transmit the identification data to the second base station.

Drawings

Fig. 1 is a communication system using methods and apparatus for neighbor base station discovery.

Fig. 2 is a call flow diagram of an exemplary method for discovering neighboring base stations in a communication system.

Fig. 3 is a flow diagram of an example method for discovering neighboring base stations in a communication system.

Fig. 4 is an exemplary implementation of an apparatus for discovering a neighboring base station in a communication system.

Fig. 5 is a flow diagram of an exemplary method that may be employed in an access terminal or similar device for neighbor discovery of base stations in a communication system.

Fig. 6 is an exemplary apparatus that may be employed in an access terminal or similar device for neighbor discovery of base stations in a communication system.

Fig. 7 is another example of a communication system with integrated base stations and access terminals using neighbor base station discovery.

Fig. 8 is another example of a communication system that uses other aspects of neighbor base station discovery.

Fig. 9 is another exemplary apparatus that may be utilized for neighbor discovery of a base station in a communication system.

Fig. 10 is yet another exemplary apparatus that may be employed for neighbor discovery of a base station in a communication system.

Detailed Description

The presently disclosed methods and apparatus enable Neighbor Discovery (ND) of base stations in a communication system, and more particularly, automatic neighbor discovery performed by base stations with access terminals. That is, an access terminal that detects wireless broadcast identification information from a base station may communicate the above information to other base stations to assist the base station in the ND. Once ND is performed, the base station may update the network (e.g., RAN) of the base station to exchange information between neighboring base stations via any one or more means, such as a gateway/network, to achieve sufficient operational capability. Manual configuration of newly added (or removed) base stations can be cancelled by using identification information (e.g., pilot ID) that has been normally detected by the access terminal and reported to the base station during handoff.

In the examples described below, the present disclosure uses terminology associated with Ultra Mobile Broadband (UMB) technology for reasons of brevity and clarity. However, it should be emphasized that the presently described examples are also applicable to other technologies, such as those related to Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), and Orthogonal Frequency Division Multiple Access (OFDMA), among others. It will be understood by those skilled in the art that when applying the disclosed methods and apparatus to other technologies, the associated terminology will be significantly different.

Turning to fig. 1, this figure illustrates a communication system 100 in which the presently disclosed methods and apparatus may be used. As shown, the communication system 100 includes AT least one base station 102 or similar apparatus for providing communications to one or more mobile devices, such as an access terminal 104 (AT). In this particular example using the terminology of UMB, the base station 102 is an evolved base station (eBS), which is named eBS₁。

Each base station in communication system 100 communicates with a gateway/network 106. Again using the terminology of UMB, gateway/network 106 may be comprised of an Access Gateway (AGW) connected to a wide area network such as the internet. The coupling of the gateway/network 106 to the base stations (eBSs), such as coupling 108, provides an extension of the Internet Protocol (IP) to each eBS in the communication system 100, which also enables faster handoff of ATs between the base stations of the system 100. The ensemble of eBSs in communication with gateway/network 106 implements a converged access network or Radio Access Network (RAN) 109.

Each base station in communication system 100 periodically transmits respective association or identification information regarding the overhead channels. Examples of the type of information contained in the identification information using UMB terminology include network identification information (e.g., ANID, which may contain an IP address, a mechanism for mapping the network identification information to an IP address; or a sector ID), and a pilot ID (pilotid). Thus, when an AT such as AT104 is slave to an eBS such as in FIG. 1₂110, the current serving base station eBS detects the pilot channel, and more specifically the pilot ID, first₁It needs to know the second base station eBS₂To assist the AT104 in receiving the network ID information from the eBS₁Handover to eBS₂。

If the network information of the neighboring base stations is not known by the current serving base station, the configuration of the base station with the identification information is required to provide sufficient communication system functions (e.g., paging and data tunneling). Examples of such identification information may generally include the IP address of the base station, geographic location, paging related information, topology and routing information, and protocol interface version. In the system of fig. 1, each base station may be configured to use AT wireless communication and additional information wirelessly transmitted thereto by other base stations to automatically add or delete (in the event that the base station is no longer serving) base stations from the neighbor list maintained by the base station.

In one aspect of automatic Neighbor Discovery (ND), a current base station eBS in the communication system 100₁The serving AT104 detects a signal containing identification data (e.g., pilot ID and ANID or sector ID)112 from a neighboring base station 110. For certain operations, such as the handoff of the AT104 from one eBS (i.e., the serving eBS 102) to another (e.g., the eBS 110, referred to as a "target" eBS) as described above, it is desirable that all base stations have information about each other's operating parameters and capabilities.

Accordingly, the AT104 may then transmit or report the identification data detected from the transmitted identification data 112 to the current serving base station 102, as illustrated by communication link 114. If the base station 102 does not recognize the base station 110, the base station 102 requests network identification information (e.g., ANID or sector ID) about the unknown base station (110 in this example) from the AT104, as shown by communication link 116. Here, the AT104 can then respond to the request from the eBS with the ANID or sector ID information₁102.

Once eBS₁With respect to a new base station eBS₂110, then, as an example, the eBS₁May be directed to the eBS via the gateway/network 106 (and communication links 108, 118)₂Issues a query for one or more requested data. New base station eBS₂To eBS via gateway/network 106₁Sending the requested information, eBS₁102 use the above information to update their neighbor lists or the likeA data structure to track possible feasible target neighbor base stations. According to another aspect, a new base station eBS₂Or to the base station eBS via the gateway/network 106₁A neighbor discovery request is initiated. It should be noted herein that querying one or more requested data via gateway/network 106 is merely exemplary and not limiting, and this information may be exchanged by any number of various means including wireless links using sector ID address information.

Fig. 2 illustrates a call flow diagram of a process for neighbor discovery that may be used in the communication system of fig. 1. As shown, AT an access terminal AT 202, a first serving base station eBS₁204 and a target base station eBS₂206, the call flow shown is in progress. It should be noted that the vertical direction of call flow 200 represents the temporal or sequential order of messages between the various devices.

As shown in block 208, except for the current serving base station eBS₁204, the AT 202 may also be configured to receive eBS from another base station eBS₂206 detect or sense the pilot. When the AT 202 is from the eBS₂206 (hereinafter referred to as Pilot ID2 in this example), the AT 202 sends the current serving base station eBS₁204 report the pilot ID2 as shown by message 210. If eBS₁204 fail to identify the eBS from the pilot ID2₂206 (as an example, when eBS₂This may happen when it has been newly added to the network), the eBS₁AT 202 is responded to with a request message requesting a sector ID associated with pilot ID2, as shown by message 212. In response to the request 212, the AT 202 then uses the sector ID of the pilot ID2 to the eBS₁204 sends a response 214, the sector ID being wirelessly from the eBS₂206 transmitted pilot.

Once the base station eBS₁204 has an eBS₂206 sector ID information, eBS₁To eBS₂206 sends a Neighbor Discovery (ND) request 216 to initiate a neighbor discovery process (e.g., obtain protocol revision, supported AGW address, location, area information)Etc.). Specifically, eBS₁204 may be directed to the eBS via an AGW such as 106 in FIG. 1 or other suitable gateway/network₂206 sends a request 216. In response, the eBS₂206 may request the base station eBS₁204 sends a neighbor discovery report message 218. Additionally, the request 216 may include a request to the eBS₁Associated Pilot ID (i.e., Pilot ID1), where the eBS₂eBS₁Is associated with pilot ID 1. The at-eBS can also be used₁The timer of (2) to ensure that the request is answered in a certain timing, 220. Slave eBS₂To eBS₁The reception of the transmitted report message 218 will stop the timer. Upon receiving the report message, the eBS₁204 eBS₂Associated with the pilot ID2, and stores the eBS₂ND information (and stopping the timer if used).

Further optionally, the new base station eBS₂206 may send a message 222 from the eBS₁204 requesting ND information, said message 222 being similar to that requested by the eBS₁204, to the message 216. In response, the eBS₁204 sends a message 224 to the eBS₂206 report their ND information. In addition, eBS₂206 may use a timer to measure a specified period 226. Therefore, when eBS₂206 sends a message 222, a timer is started and then stopped upon receipt of a message 224.

Fig. 3 illustrates a flow diagram of a method of neighbor discovery that may be used with the system of fig. 1. In particular, it may be at a base station (e.g., the eBS shown in FIGS. 1 and 2)₁Or eBS₂) To implement the method 300. As shown, after initialization, the method 300 includes a block 302 in which a base station (e.g., eBS)₁) Based on pairing by an access terminal from a first base station (e.g., an eBS) in a communication network₂) And receiving a first message from the AT. This process is similar to message 210 in fig. 2, where the identification signal is a pilot ID. Note that the processing of block 302 may be initiated by a request from the AT, such as seeking assistance AT the ATTo determine a feasible target base station to hand over to.

After block 302, flow proceeds to decision block 304 where it is determined whether the first base station is an identified base station based on an identification signal (e.g., pilot ID). This check may be done by searching a neighbor table stored at the base station to determine if the pilot ID is known. If the base station identifies the pilot ID, no further neighbor discovery need be performed at this point, and process 300 may terminate. Alternatively, if the pilot ID of the base station is not known, flow may proceed to block 306. AT block 306, the base station sends a second message to the AT requesting a network identification, which may be obtained by the AT from pilots of other base stations. This second message of block 306 is similar to message 212 in fig. 2, for example, where a network identification (e.g., sector ID or ANID) is requested.

After block 306, flow proceeds to block 308 where, in response to the request of block 306, the base station receives a third message from the AT that includes the network identification of the first base station. Note that the third message in the processing of block 308 is similar to message 214 illustrated in fig. 2, and the network identification may be a sector ID or ANID, as examples. After receiving the network identification, the base station sends a request for identification data unique to the first base station according to the network identification, as shown in block 310. Note that the process of sending the request based on the network identification in block 310 may include: the network identification of the first base station is first used in sending a request according to the network identification to resolve or derive the IP address of the first base station. It should also be noted that the request may be sent over a network other than the wireless resource, such as gateway/network 106 shown in fig. 1, but is not limited to such and may include various means of including wireless resources. An example of a request in block 310 is ND request 216 in FIG. 2. Additionally, the requested identification data related to the first base station may generally include, but is not limited to, the geographic location of the first base station, paging related information, topology and routing information, and protocol interface version.

After sending the request in block 310 over the network, the process 300 for initiating Neighbor Discovery (ND) may be characterized as complete from the perspective of the serving base station. However, intuitively, the receipt of the identification data from the first base station will complete the neighbor discovery process, which allows the serving base station to assist the AT in handing off to the first base station. Thus, a further optional block 312 (shown in dashed lines) is shown in fig. 3, indicating the receipt of identification data back from the first base station and the updating of the neighbour list at the serving base station. The processing of block 312 is similar to the ND report message 218 shown in FIG. 2.

Further optionally, the method 300 may also include receiving a request for neighbor information (e.g., a neighbor list) from the first base station, wherein the neighbor information is known to the apparatus (i.e., the other base station) performing the method 300. The device then sends neighbor information to the requesting first base station, as shown by the dashed box 314. Note that the processing of block 314 is similar to the functionality implemented by messages 222 and 224 shown in fig. 2.

Fig. 4 schematically shows an exemplary implementation of an apparatus 400 for performing the above-described method. The apparatus 400 may be implemented in a server implemented with an eBS, which is merely an example, and may be implemented in any other suitable apparatus. The apparatus 400 has a central data bus 402 or similar device for linking several circuits together. The circuits include a CPU (central processing unit) or controller 404, transceiver circuits 406, network interface circuits 408, and a memory unit 410.

The transceiver circuit 406 includes: receive circuitry for processing the received signal before sending it out to the central data bus 402; and transmit circuitry to process and buffer data from the data bus 402 before being transmitted from the device 400 (e.g., to the illustrated AT). Additionally, where the apparatus 400 is used in a base station, the transceiver circuitry 406 may include RF circuitry for transmitting over a wireless link 410 to one or more ATs.

The CPU/controller 404 performs the data management functions of the data bus 402 as well as the general data processing functions including executing the instructional contents of the memory unit 410. It is noted here that instead of being implemented separately as shown in fig. 4, the transceiver circuitry 406 may instead be included as part of the CPU/controller 404. As another alternative, the entire apparatus 400 may be implemented as an Application Specific Integrated Circuit (ASIC) or similar apparatus.

The memory unit 410 may include one or more instruction sets/modules. In the exemplary apparatus 400, the instructions/modules include, inter alia, a Neighbor Discovery (ND) function 414 configured to implement the methods described herein. The memory unit 410 may also include a neighbor list 416 or similar data structure that specifically stores identification data of neighboring data or references other memory using at least a portion of the identification data.

In the example of fig. 4, the memory unit 410 may be a RAM (random access memory) circuit. Exemplary portions, such as functionality 414, are software routines, modules, and/or data sets. The memory unit 410 may be connected to another memory circuit (not shown), which may be of a volatile or non-volatile type. Alternatively, memory unit 410 may be formed from other circuit types, such as EEPROM (electrically erasable programmable read Only memory), EPROM (electrically programmable read Only memory), ROM (read Only memory), ASIC (application specific Integrated Circuit), magnetic disks, optical disks, and other computer readable media known in the art.

It should also be noted that the network interface circuitry 408 may be used to implement neighbor discovery functionality, such as communicating with a gateway/network 418 similar to the gateway/network 106. In particular, the circuitry 408 may be used to send and receive messages for obtaining identification data from other devices in the communication network 418, for use in neighbor discovery, and the like.

Fig. 5 illustrates a flow chart of an exemplary method, which may be implemented by an AT or similar device, for neighbor discovery of base stations in a network. As shown, the method 500 includes block 502, where the AT detects an identification signal from a first base station in communication. Such detection may include detecting a pilot channel of the first base station, and the identification signal may include a pilot ID of the first base station. An example of such detection is shown at block 208 in fig. 2. Upon detecting the identification signal, the AT then sends a request to the second base station to assist the AT in handing over to the first base station based on the identification signal, as shown in block 504. Note that this message request is similar to the report message 210 illustrated by fig. 2.

After sending the message in block 504, the second base station will determine whether the first base station is known in the communication network. If not, the second base station will send a message to the AT requesting network identification information about the first base station. Thus, from the perspective of the AT, when the second base station determines that the first base station is not a known base station, the AT receives the message from the second base station, wherein the message requests network identification data from the AT regarding the first base station, as shown in block 506. Note that the process of block 506 may be illustrated by request 212 in fig. 2, and the network identification data may include the sector ID or ANID of the first base station.

Following the processing of block 506, the method 500 proceeds to block 508, where the AT obtains network identification data (e.g., sector ID). As described above, the pilot signal (e.g., 112 in fig. 1) broadcast by the first base station will include this data. Thus, the AT thus obtains the network identification data, e.g., from the pilot signal, and then transmits the network identification data to the second base station, as shown in block 510. The processing of block 510 is similar to sector ID response 214 shown in fig. 2. The second base station may then initiate a ND procedure using the network identification data to register the first base station and add the first base station to its list of known neighbors, for example as discussed above with reference to fig. 2 and 3.

Fig. 6 illustrates an exemplary apparatus 600 that may be used to implement the method of fig. 5. Note that apparatus 600 may constitute an AT or other suitable hardware (e.g., a processor or collection of circuits/modules) for use in an AT device. As shown, the apparatus 600 includes a central data bus 602 or similar device for linking several circuits together. The circuits include a CPU (central processing unit) or controller 604, transceiver circuits 606, a network, and a memory unit 608.

The transceiver circuit 606 includes: receive circuitry for processing the received signal before sending it out to the central data bus 602; and transmit circuitry to process and buffer data from the data bus 602 before sending the data out of the device 600 (e.g., to one or more ebss as shown by one or more wireless communication links 610). Accordingly, the transceiver circuitry 606 may include RF circuitry to transmit over the wireless link 610 to one or more eBSs.

The CPU/controller 606 performs data management functions of the data bus 602, as well as general data processing functions, including executing the instructional contents of the memory unit 608. It is noted here that instead of being implemented separately as shown in fig. 6, the transceiver circuit 606 may instead be included as part of the CPU/controller 604. As another alternative, the entire apparatus 600 may be implemented as an Application Specific Integrated Circuit (ASIC) or similar apparatus. Memory unit 610 may include one or more sets/modules of instructions. In the example apparatus 600, the instructions/modules include, inter alia, Neighbor Discovery (ND) functionality 612 configured to implement the methods described herein, i.e., fig. 5.

In the example of fig. 6, the memory unit 610 may be a RAM (random access memory) circuit. Exemplary portions, such as functionality 414, are software routines, modules, and/or data sets. The memory unit 610 may be connected to another memory circuit (not shown), which may be of a volatile or non-volatile type. Alternatively, memory unit 610 may be comprised of other circuit types such as EEPROM (electrically erasable programmable read Only memory), EPROM (electrically programmable read Only memory), ROM (read Only memory), ASIC (application specific Integrated Circuit), magnetic disks, optical disks, and other computer readable media known in the art.

FIG. 7 illustrates the use of neighbor transmissionAnother example of a present communication system 700. In this example, it is contemplated that the base station (eBS) may include an integrated and dedicated AT unit for ND procedures, rather than any AT currently served by the base station. As can be seen in FIG. 7, the base station eBS₁702 includes an AT 704. At eBS₁The AT 704 in 702 is driven from another neighboring base station (e.g., eBS) in the same manner as the AT104 discussed in connection with FIG. 1₂708) A pilot signal is detected or received 706. Note, however, that the AT 704 must be AT another eBS (e.g., eBS)₂708) In order to efficiently complete the ND process. Upon detection of the pilot signal, interaction of the AT 704 with other elements of the base station 702 is performed in the same manner as previously discussed with reference to fig. 2, 4, and 5 to complete the ND over the network/network 710 and additional links 712 and 714.

It should also be noted that the eBS in the example of FIG. 7 may be implemented using similar apparatus to those described herein with reference to FIGS. 4 and 6₁And an AT. It should also be noted that the elements of apparatus 400 and 600 may overlap and may be combined into a single unit having modules or circuitry for performing the methods of fig. 3 and 5.

Fig. 8 illustrates another example of a communication system 800 that uses neighbor discovery. In the example of FIG. 8, a first base station eBS₁802 serve ATs 804 over a wireless link 806. In this example, the area 808 in which the AT 804 may currently be located is a coverage area in which coverage may be provided by, for example, the eBS₀810 and eBS₂812, or the like, for communication services (e.g., voice, paging, etc.). In the example of FIG. 8, assume for illustration an eBS₀810 for eBS₁802 are known neighbors, therefore eBS₀810 is eBS₁Is part of the neighbor list of (a). When the new base station, i.e. eBS₂812 is added to the base station eBS by the method described above₁802 neighbor list, base station eBS₁Can be configured to then update, for example, eBS₀810, which may also beServing the same coverage area 808. Thus, eBS₁802 will send the slave eBS via ND procedure₂Received information about eBS₂812, identification data. This transmission may occur via network/network 814 and associated communication links 816 and 818. Thus, eBS₁802 new or updated neighbor list (which will include the eBS)₀And eBS₂) Is sent to the eBS₀810 to update its neighbor list. Similarly, eBS₁The newly discovered eBS may also be directed to via gateway/network 814 and associated communication links 816 and 820₂812 sends its updated neighbor list.

Note that there may be situations during the ND procedure where the identification signal or network identification of the newly added base station conflicts with the identification signal or network identification of an existing neighboring base station. In this case, the base station performing the ND procedure may be configured to mediate the collision. Using the system 800 in FIG. 8, for illustration purposes, if the AT 804 uses the ND method described previously from the new base station eBS₂812 detects or receives a pilot signal 822 having a pilot ID, the AT 804 will transmit to the serving base station (i.e., eBS)₁802) The pilot ID is sent. For example, if the serving base station detects an eBS with e.g. a neighboring base station₀810, the serving base station eBS₁802 may initiate a mediation. The mediation may consist of: the serving base station communicates to the neighboring base stations 810 and 812 via the gateway/network 814 to issue a request to at least one of the base stations 810 or 812 to change its respective pilot ID. Such a mediation process may be implemented in any number of suitable ways known to those skilled in the art. The mediation process may also include initiating registration of the new base station 812 and sending updated information to all base stations in its current neighbor list. Also, the updated pilot ID information can be actively transmitted to the AT 804 by the serving base station over the wireless link 806, or alternatively, transmitted to the AT 804 in a somewhat more passive manner by the AT 804 via subsequent detection or reception of the pilot signal 822. Note that the neighbor messages disclosed in FIG. 4 may be sent by way of exampleNow function 414 implements the mediation function.

Fig. 9 illustrates an apparatus 900 for use in a communication system that may be utilized for neighbor discovery of base stations. Apparatus 900 can be implemented, for example, in a base station, comprising a module 902 for receiving a first message from an access terminal to assist the access terminal in handing over from a second base station to a first base station in a communication network based on detection by the access terminal of an identification signal from the first base station. Information received by module 902 may then be transmitted to various other modules in device 900 via bus 904 or similar appropriate communication connection. In particular, the first message and/or the identification signal may be sent to module 906 to determine whether the first base station is a known base station based on the identification signal.

Apparatus 900 further includes a module 908 for sending a second message to the access terminal requesting network identification of the first base station when the first base station is not a known base station, e.g., as determined by module 906. Apparatus 900 further includes a module 910 for receiving, e.g., from the access terminal, a third message in response to the second message sent by module 908, wherein the third message includes the network identification of the first base station. Module 912 is also for sending a request for identification data to the first base station based on the network identification received by module 910. Additionally, apparatus 900 may include an optional computer-readable medium or memory device 914, memory device 914 being configured to store computer-readable instructions or data to implement the processes and acts of any of the described modules. Additionally, the apparatus 900 may include a processor 916 for executing computer readable instructions in the memory 914 and may be configured to perform one or more functions of the various modules in the apparatus 900.

Fig. 10 illustrates an apparatus 1000 for use in a communication system that may be used for neighbor discovery of base stations. Apparatus 1000 can be implemented, for example, in an access terminal, including a module 1002 for detecting, at the access terminal, an identification signal from a first base station in a communication network. Information received by module 1002 may then be transmitted to various other modules in device 1000 via bus 704 or other similar communication connection. In particular, an identification signal may be sent to module 1006 to send a request to the second base station to assist the access terminal in handing over to the first base station based on the identification signal.

Apparatus 1000 also includes a module 1008 for receiving a message from the second base station requesting identification data of the first base station when the second base station determines that the first base station is not a known base station. The apparatus 1000 further comprises: a module 1010 for obtaining identification data from a first base station; and a module 1012 for then transmitting the identification data to the second base station. Moreover, apparatus 1000 may include an optional computer-readable medium or memory device 1014 configured to store computer-readable instructions and data for implementing the processes and acts of any of the described modules. Additionally, the apparatus 1000 may include a processor 1016 for executing computer readable instructions in a memory 1014 and may be configured to perform one or more functions of the various modules in the apparatus 1000.

From the foregoing discussion, it can be appreciated that the presently disclosed methods and apparatus provide for efficient discovery of neighboring base stations added to a communication system with minimal impact on the radio resources in the system. Those skilled in the art will also appreciate that the present methods and apparatus are also useful for updating neighbor lists when a base station is removed from a communication system.

It is to be understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. It will be appreciated that, depending upon design preferences, the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. 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.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, means, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but, in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium (not shown) may be coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

The above examples are merely exemplary and those skilled in the art may now make numerous uses of, and departures from, the above examples without departing from the inventive concepts disclosed herein. Various modifications to these examples may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other examples, e.g., in an instant messaging service or any general wireless data communication applications, without departing from the spirit or scope of the novel aspects described herein. Thus, the scope of the present disclosure is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Note that the word "exemplary" is used exclusively herein to mean "serving as an example, instance, or illustration. Any example described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other examples. Accordingly, the novel aspects described herein are to be defined solely by the scope of the following claims.

Claims (52)

1. A method of discovering a first base station by a second base station in a communication system, the method comprising:

receiving a first message from an access terminal to assist the access terminal in handing over from the second base station to the first base station in accordance with detection by the access terminal of an identification signal from the first base station in the communication system;

determining from the identification signal whether the first base station is a known base station;

when the first base station is determined not to be a known base station, sending a second message to the access terminal requesting a network identification of the first base station;

receiving, from the access terminal, a third message containing the network identification of the first base station in response to the second message; and

and sending a request for identification data to the first base station according to the network identification.

2. The method of claim 1, wherein the network identification comprises at least one of a sector ID and an ANID, and the identification data comprises at least one of a geographical location of the first base station, paging related information, topology information, routing information, and a protocol interface version.

3. The method of claim 1, wherein the access terminal is integrated with the second base station.

4. The method of claim 1, wherein the network link comprises at least one of an access gateway and an IP network.

5. The method of claim 1, wherein determining whether the first base station is a known base station from the identification signal comprises: comparing at least a portion of the identification signal to a neighbor list of currently registered base stations known to the second base station.

6. The method of claim 5, further comprising:

interceding between the first base station and a third base station when the second base station detects a conflict between at least one of the identification data and network data of the first base station and a corresponding at least one of identification data and network data of a third, neighboring base station.

7. The method of claim 1, further comprising:

receiving a reply containing identification data from the first base station in response to the request for identification data; and

registering the first base station in a neighbor list of the second base station using at least a portion of the identification data.

8. The method of claim 7, further comprising:

transmitting at least a portion of the information in the neighbor list to at least one third neighboring base station in the communication system via a network link.

9. An apparatus for discovering base stations in a communication network, comprising:

transceiver circuitry to receive a first message from an access terminal to assist the access terminal in handing over from a second base station to a first base station in a communication system based on detection by the access terminal of an identification signal from the first base station;

a neighbor discovery module for determining whether the first base station is a known base station according to the identification signal; wherein the transceiver circuitry is further to transmit a second message to the access terminal requesting a network identification of the first base station when the neighbor discovery module determines that the first base station is not a known base station; and, receiving a third message from the access terminal containing the network identification of the first base station in response to the second message; and

a network interface circuit for sending a request for identification data to the first base station via a network link in accordance with the network identification.

10. The apparatus of claim 9, wherein the network identification comprises at least one of a sector ID and an ANID, and the identification data comprises at least one of a geographical location of the first base station, paging related information, topology information, routing information, and a protocol interface version.

11. The apparatus of claim 9, wherein the access terminal is integrated with the second base station.

12. The apparatus of claim 9, wherein the network link comprises at least one of an access gateway and an IP network.

13. The apparatus of claim 9, wherein the neighbor discovery module is further configured to determine whether the first base station is a known base station based on the identification signal by comparing at least a portion of the identification signal to a neighbor list of currently registered base stations known to the second base station.

14. The apparatus of claim 13, wherein the neighbor discovery module is further configured to mediate between the first base station and a third base station when the second base station detects a collision between at least one of the identification data and network data of the first base station and a corresponding at least one of identification data and network data of a third neighboring base station.

15. The apparatus of claim 9, wherein the network interface circuit is further to: receiving a reply containing identification data from the first base station in response to the request for identification data; and the neighbor discovery module is further configured to register the first base station in a neighbor list of the second base station using at least a portion of the identification data.

16. The apparatus of claim 15, wherein the neighbor discovery module is further configured to instruct the network interface circuitry to transmit at least a portion of the information in the neighbor list to at least one third neighboring base station in the communication system via the network link.

17. An apparatus for use in a communication system, comprising:

means for receiving a first message from an access terminal to assist the access terminal in handing over from a second base station to a first base station in a communication network based on detection by the access terminal of an identification signal from the first base station;

means for determining whether the first base station is a known base station based on the identification signal;

means for transmitting a second message to the access terminal requesting a network identification of the first base station when it is determined that the first base station is not a known base station;

means for receiving a third message from the access terminal in response to the second message containing the network identification of the first base station; and

means for sending a request for identification data to the first base station based on the network identification.

18. The apparatus of claim 17, wherein the network identification comprises at least one of a sector ID and an ANID, and the identification data comprises at least one of a geographical location of the first base station, paging related information, topology information, routing information, and a protocol interface version.

19. The apparatus of claim 17, wherein the access terminal is integrated with the second base station.

20. The apparatus of claim 17, wherein the network link comprises at least one of an access gateway and an IP network.

21. The apparatus of claim 17, wherein the means for determining whether the first base station is a known base station from the identification signal comprises: means for comparing at least a portion of the identification signal to a neighbor list of currently registered base stations known to the second base station.

22. The apparatus of claim 21, further comprising:

means for mediating between the first base station and a third base station when the second base station detects a conflict between at least one of the identification data and network data of the first base station and a corresponding at least one of identification data and network data of a third neighboring base station.

23. The apparatus of claim 17, further comprising:

means for receiving a reply containing identification data from the first base station in response to the request for identification data; and

means for registering the first base station in a neighbor list of the second base station using at least a portion of the identification data.

24. The apparatus of claim 23, further comprising:

means for transmitting at least a portion of the information in the neighbor list to at least one third neighbor base station in the communication system via a network link.

25. A computer program product, comprising:

a computer readable medium, the computer readable medium comprising:

code for causing a computer to receive a first message from an access terminal to assist the access terminal in handing over from a second base station to a first base station in a communication system based on detection by the access terminal of an identification signal from the first base station;

code for causing a computer to determine whether the first base station is a known base station based on the identification signal;

code for causing a computer to transmit a second message to the access terminal requesting a network identification of the first base station when it is determined that the first base station is not a known base station;

code for causing a computer to receive, from the access terminal, a third message containing the network identification of the first base station in response to the second message; and

code for causing a computer to transmit a request for identification data to the first base station in accordance with the network identification.

26. The computer program product of claim 25, wherein the network identification comprises at least one of a sector ID and an ANID, and the identification data comprises at least one of a geographic location of the first base station, paging related information, topology information, routing information, and a protocol interface version.

27. The computer-program product of claim 25, wherein the access terminal is integrated with the second base station.

28. The computer program product of claim 25, wherein the network link comprises at least one of an access gateway and an IP network.

29. The computer program product of claim 25, wherein the computer-readable medium comprises code for causing a computer to determine whether the first base station is a known base station based on the identification signal further comprises: code for causing a computer to compare at least a portion of the identification signal to a neighbor list of currently registered base stations known to the second base station.

30. The computer program product of claim 29, the computer-readable medium further comprising:

code for causing a computer to mediate between the first base station and a third base station when the second base station detects a conflict between at least one of the identification data and network data of the first base station and a corresponding at least one of identification data and network data of a third, neighboring base station.

31. The computer program product of claim 25, the computer-readable medium further comprising:

code for causing a computer to receive a response containing identification data from the first base station in response to the request for identification data; and

code for causing a computer to register the first base station in a neighbor list of the second base station using at least a portion of the identification data.

32. The computer program product of claim 31, the computer-readable medium further comprising:

code for causing a computer to transmit at least a portion of the information in the neighbor list to at least one third neighboring base station in the communication system via a network link.

33. A method of discovering a base station in a communication system, the method comprising:

detecting, at an access terminal, an identification signal from a first base station in a communication network;

sending a request to a second base station according to the identification signal to help the access terminal to be switched to the first base station;

receiving a message requesting identification data of the first base station from the second base station when the second base station determines that the first base station is not a known base station;

obtaining the identification data from the first base station; and

transmitting the identification data to the second base station.

34. The method of claim 33, wherein the identification data comprises at least one of a sector ID and an ANID.

35. The method of claim 33, wherein the access terminal is integrated with the second base station.

36. The method of claim 33, wherein the second base station determines whether the first base station is a known base station from the identification signal by comparing at least a portion of the identification signal to a neighbor list of currently registered base stations known to the second base station.

37. The method of claim 33, further comprising:

receiving at least one of updated identification signal information and updated identification data from at least one of the first and second base stations based on mediation between the first and third base stations by the second base station when the second base station detects a conflict between the at least one of identification data and network data of the first base station and a corresponding at least one of identification data and network data of a third neighboring base station.

38. An apparatus in an access terminal for neighbor discovery of base stations in a communication system, the apparatus comprising:

a transceiver circuit for detecting an identification signal at an access terminal from a first base station in a communication network; sending a request to a second base station according to the identification signal to help the access terminal to be switched to the first base station; and receiving a message requesting identification data of the first base station from the second base station when the second base station determines that the first base station is not a known base station; and

a neighbor discovery module for obtaining the identification data from the first base station; and instructing the transceiver circuitry to transmit the identification data to the second base station.

39. The apparatus of claim 38, wherein the identification data comprises at least one of a sector ID and an ANID.

40. The apparatus of claim 38, wherein the access terminal is integrated with the second base station.

41. The apparatus of claim 38, wherein the second base station determines whether the first base station is a known base station from the identification signal by comparing at least a portion of the identification signal to a neighbor list of currently registered base stations known to the second base station.

42. The apparatus of claim 38, wherein the transceiver circuitry and neighbor discovery module are further configured to: receiving at least one of updated identification signal information and updated identification data from at least one of the first and second base stations based on mediation between the first and third base stations by the second base station when the second base station detects a conflict between the at least one of identification data and network data of the first base station and a corresponding at least one of identification data and network data of a third neighboring base station.

43. An apparatus in an access terminal for neighbor discovery of base stations in a communication system, the apparatus comprising:

means for detecting, at an access terminal, an identification signal from a first base station in a communication network;

means for sending a request to a second base station to assist the access terminal in handing over to the first base station based on the identification signal;

means for receiving a message from the second base station requesting identification data of the first base station when the second base station determines that the first base station is not a known base station;

means for obtaining the identification data from the first base station; and

means for transmitting the identification data to the second base station.

44. The apparatus of claim 43, wherein the identification data comprises at least one of a sector ID and an ANID.

45. The apparatus of claim 43, wherein the access terminal is integrated with the second base station.

46. The apparatus of claim 43, wherein the second base station determines whether the first base station is a known base station based on the identification signal by comparing at least a portion of the identification signal to a neighbor list of currently registered base stations known to the second base station.

47. The apparatus of claim 43, further comprising:

means for receiving at least one of updated identification signal information and updated identification data from at least one of the first base station and the second base station based on a mediation between the first base station and the third base station by the second base station when the second base station detects a conflict between the at least one of the identification data and network data of the first base station and a corresponding at least one of identification data and network data of a third neighboring base station.

48. A computer program product, comprising:

a computer readable medium, the computer readable medium comprising:

code for causing a computer to detect, at an access terminal, an identification signal from a first base station in a communication network;

code for causing a computer to transmit a request to a second base station to assist the access terminal in handing over to the first base station in accordance with the identification signal;

code for causing a computer to receive a message from the second base station requesting identification data of the first base station when the second base station determines that the first base station is not a known base station;

code for causing a computer to obtain the identification data from the first base station; and

code for causing a computer to transmit the identification data to the second base station.

49. The computer program product of claim 48, wherein the identification data comprises at least one of a sector ID and an ANID.

50. The computer-program product of claim 48, wherein the access terminal is integrated with the second base station.

51. The computer program product of claim 48, wherein the second base station determines whether the first base station is a known base station from the identification signal by comparing at least a portion of the identification signal to a neighbor list of currently registered base stations known to the second base station.

52. The computer program product of claim 33, the computer-readable medium further comprising:

code for causing a computer to receive at least one of updated identification signal information and updated identification data from at least one of the first and second base stations based on mediation between the first and third base stations by the second base station when the second base station detects a conflict between the at least one of identification data and network data of the first base station and a corresponding at least one of identification data and network data of a third neighboring base station.