Abstract:
A method for configuring a network is described, the method comprising: receiving, from a first radio node in the network, network information associated with one or more second radio nodes in the network; generating a network relation table, the network relation table comprising network information associated with the first radio node and the one or more second radio nodes; and performing a handoff to a third radio node in the network using the network relation table.

Description:
CLAIM OF PRIORITY 
     This application is a continuation of and claims priority under 35 U.S.C. §120 to U.S. application Ser. No. 12/797,138, filed on Jun. 9, 2010, to be issued on Feb. 26, 2013 as U.S. Pat. No. 8,385,291, which in turn claims priority under 35 U.S.C. §119(e) to provisional U.S. Patent Application No. 61/185,757, filed on Jun. 10, 2009, the entire contents of each of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     3G (“third generation”) networks are widely deployed networks that provide users with a wide range of wireless services including wireless voice telephone, video calls, and broadband wireless data. Examples of 3G technologies include code division multiple access (“CDMA”) 2000, Wideband Code Division Multiple Access (WCDMA), High Speed Packet Access (HSPA) and Evolution-Data Optimized (“EVDO”), which was originally referred to as High Data Rate (“HDR”). CDMA and EVDO refer to the same 3G technology but represent various evolutions of the 3G technology. WCDMA and HSPA refer to the same 3G technology but represent various evolutions of the 3G technology. 
     The CDMA standard is used for high-speed data-only services. CDMA has been standardized by the Telecommunication Industry Association (“TIA”) as TIA/EIA/IS-856 (see “CDMA2000 High Rate Packet Data Air Interface Specification,” 3GPP2 C.S0024-0, Version 4.0, Oct. 25, 2002, which is incorporated herein by reference. Revision A to this specification has been published as TIA/EIA/IS-856, “CDMA2000 High Rate Packet Data Air Interface Specification,” 3GPP2 C.S0024-A, Version 2.0, June 2005, and is also incorporated herein by reference). 
     The Universal Mobile Telecommunications Standard (UMTS) is used for both voice and high-speed data services. UMTS is a globally applicable set of technical specifications and technical reports for a 3G mobile system supporting UTRA Frequency Division Duplex (FDD) and Time Division Duplex (TDD), Global System for Mobile Communication (GSM) including General Packet Radio Service (GPRS), Enhanced Data Rates for GSM Evolution (EGDE) and Long Term Evolution (LTE). The UMTS standards are published and maintained by 3GPP which is also incorporated herein by reference. 
     The EVDO standard is used for the wireless transmission of data through radio signals, using multiplexing techniques including CDMA to maximize both individual user&#39;s throughput and the overall system throughput. EVDO was designed as an evolution of the CDMA 2000 standard that would support high data rates and could be deployed alongside a wireless carrier&#39;s voice services. Initially, the EVDO standard was named High Data Rate (HDR), but was renamed to EVDO after the standard was ratified by the International Telecommunication Union (“ITU”). (See P. Bender, et al., “CDMA/HDR: A Bandwidth-Efficient High-Speed Wireless Data Service for Nomadic Users,” IEEE Communications Magazine, July 2000; and Third Generation Partnership Project 2 (“3GPP2”), “Draft Baseline Text for 1xEV-DO,” Aug. 21, 2000). 
     Advances in telecommunications technology have brought forth a newly developed class of technologies referred to as 4G (“fourth generation”). Examples of 4G technology include Long-Term Evolution (“LTE”) and Worldwide Interoperability for Microwave Access (“WiMAX”) telecommunications technologies. Generally, 3G networks, such as EVDO, have wide deployment. 4G networks, such as WiMAX and LTE, are deployed in a limited area (concentrated in larger cities, for example) and often have limited coverage area. 
     In telecommunications, the term handover or “handoff” refers to the process of transferring an ongoing call or data session from one radio node connected to a core network, for example using 3G or 4G technology, to another radio node. Generally, a “hard handoff” is one in which a communication with a radio node in a source cell is released and then the communication in a target cell is engaged. Thus, the connection to the source cell is broken before the connection to the target cell is established. A “soft handoff” is one in which the communications in the source cell are retained and are used in parallel with communications in the target cell. In a soft handoff, the connection to the target cell is established before the connection to the source cell is broken. A soft handoff may involve using connections to more than two cells, e.g., connections to three, four or more cells can be maintained by one handset at the same time. 
     Home base-stations, which are also referred to as “femto cells,” may be deployed in residences, in public hot-spot areas and in enterprises, e.g., company buildings or campuses, to provide wireless coverage using 3G and 4G technologies. With public hot-spot and enterprise deployments, femto cells are deployed as a connection of radio nodes that allow a handset to maintain a call while travelling through the physical domain of the enterprise. In order to maintain the call in current systems, an engineer or technician selects cell sites, puts up towers, designates one cell as a central controller, and configures the central controller to control mobility from one cell to another. Based on this manual configuration, as the handset transitions from one node to another, the call is maintained using one or more soft handovers. 
     The description uses the following acronyms:
         HNB—Home Node B (e.g., a home base station)   CSG—Closed Subscriber Group   CSG Id—CSG Identifier, which includes a numerical identifier (“Id”). A CSG HNB advertises a CSG Id so that handsets with membership at the HNB can access the CSG. A HNB broadcasts its CSG Id in the broadcast channel.   UPnP—Universal Plug and Play   PnP—Plug and play   HNB-GW—HNB Gateway. A gateway that provides core network connectivity for HNBs.   REM—Radio Environment Monitoring. A HNB performs REM scans to discover its neighbors.   SIB—System Information Blocks. SIBs are broadcast by a HNB on the broadcast channel and include control information for the handsets.   UUID—Universally Unique Id. UPnP devices are uniquely identified by a UUID.   UE—User Equipment, e.g., a handset.   PSC—Primary Scrambling Code. A physical identity on the HNB, which may be reused by geographically distant/separated HNBs.   UDP—User Datagram Protocol. A transport layer protocol for use with an internet protocol (“IP”) protocol suite.   RNC Id—Radio Network Control Id. A unique numerical Id of the HNB-GW within a network.   SCTP—Stream Control Transmission Protocol. A transport layer protocol for use with the IP protocol suite.   Cell Identity—A unique numerical identity for the HNB within the network.       

     SUMMARY 
     Described herein is an enterprise network configuration that enables graduated, scalable, and flexible deployment of femto cells, by allowing a radio node to be a controller either temporarily or permanently, e.g., when it is serving a handset. The enterprise network enables decentralized handover processes, and may do so without a designated centralized controller responsible for managing handovers. Also described are methods by which the enterprise network auto-configures itself, e.g., through a self-discovery process, and implements handovers. 
     In one aspect of the present disclosure, a method for configuring a network, comprises: receiving, from a first radio node in the network, network information associated with one or more second radio nodes in the network; generating a network relation table, the network relation table comprising network information associated with the first radio node and the one or more second radio nodes; and performing a handoff to a third radio node in the network using the network relation table. 
     Implementations of the disclosure may include one or more of the following features. In some implementations, the third radio node comprises one of (i) the first radio node; or (ii) the one or more second radio nodes. The method further comprises sending, to the first radio node, a request for network information associated with the one or more second radio nodes in the network. 
     In other implementations, the network relation table comprises a routing table. The method also comprises receiving, from the first radio node through a radio interface, information identifying the first radio node as being in the network. The method additionally comprises using a network protocol to identify the first radio node as being in the network. 
     In still other implementations, the handoff comprises one of a soft handoff or a hard handoff, the handoff is executed through a direct communication link within the network, and the handoff is initiated following a detection, by the first radio node, of one or more of (i) a need to load balance the network, (ii) a need to maintain interference and power limits within the network, and (iii) one or more measurement reports received from a handset. The method also comprises automatically organizing one or more operational parameters based on information received about the third radio node in the network. 
     In another aspect of the disclosure, one or more machine-readable media are configured to store instructions that are executable by one or more processing devices to perform functions comprising: receiving, from a first radio node in the network, network information associated with one or more second radio nodes in the network; generating a network relation table, the network relation table comprising network information associated with the first radio node and the one or more second radio nodes; and performing a handoff to a third radio node in the network using the network relation table. Implementations of this aspect of the present disclosure can include one or more of the foregoing features. 
     In still another aspect of the disclosure, a system for configuring a network comprises a first radio device, in the network, configured to receive signals from a second radio device, in the network, and to transmit signals to the second radio device, the first radio device being configured to: receive, from a second radio node in the network, network information associated with one or more third radio nodes in the network; generate a network relation table, the network relation table comprising network information associated with the second radio node and the one or more third radio nodes; and perform a handoff to a fourth radio node in the network using the network relation table. Implementations of this aspect of the present disclosure can include one or more of the foregoing features. 
     Advantages of particular implementations include one or more of the following. Femto cells may be deployed within an enterprise network in an ad-hoc, scalable manner, without manual configuration, e.g., by an engineer or a technician, and optionally with or without a designated central controller. As the enterprise network grows, each node in the enterprise network learns of the other nodes in the enterprise network through an auto-configuration process. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram of a communications network. 
         FIG. 2  is a flow chart of processes used by the communications network. 
         FIG. 3  is a block diagram of an enterprise network. 
         FIG. 4  is a diagram of a network relation table. 
         FIGS. 5A-5D  are diagrams of a handover process. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a communication network  10  includes radio nodes  12 ,  14 ,  16 ,  18 ,  20 ,  22  (HNB [a-f]) in wireless communication with a gateway  24  (HNB-GW). A radio node  12 ,  14 ,  16 ,  18 ,  20 ,  22  may also be referred to as a “home base station,” a “base station,” or a “home node B.” Radio nodes  12 ,  14 ,  16  (HNB [a-c]) belong to an enterprise network  26 , while radio nodes  18 ,  20 ,  22  (HNB [e-f]) are private residential nodes, e.g., in different houses. Depending on the number of radio nodes in the enterprise network  26  and the configuration of the radio nodes in the enterprise network  26 , the enterprise network may have a mesh configuration, a star configuration, or any combination thereof. Though an interface (e.g., an Iuh interface, a 3GPP interface, a standardized interface, a proprietary interface, and so forth), the network  10  establishes communication links  28 ,  30 ,  32 ,  34 ,  36 ,  38  between the gateway and the radio nodes  12 ,  14 ,  16 ,  18 ,  20 ,  22 . The enterprise network  26  uses an interface (e.g., an Iux interface, a standardized interface, a proprietary interface, and so forth) to establish links  40 ,  42 ,  44  between the radio nodes  12 ,  14 ,  16  (HNB [a-c]). 
     Radio nodes  12 ,  14 ,  16  (HNB [a-c]) are assigned a group identifier, e.g., a CSG-Id, to identify the network associated with the radio nodes  12 ,  14 ,  16 . Radio nodes  12 ,  14 ,  16  belonging to the same enterprise network (e.g., enterprise network  26 ) are assigned the same CSG-Id. 
     The enterprise network  26  is configured by a discovery process (e.g., an autonomous recognition process) performed both in the radio domain and in the network domain. Through the discovery process, a control point radio node (i.e., a radio node that is servicing a handset) identifies network information (e.g., routing information, CSG-Id information, PSC information, and so forth) associated with its “neighboring radio nodes,” radio nodes that are within the radio range, and/or the network range of the control point radio node. The control point radio node also identifies network information associated with its “neighbors&#39; neighbors radio nodes,” radio nodes that are within the radio range, and/or the network range of the neighboring radio nodes. Based on the discovered network information, the control point radio nodes generates and updates a network relation table (“NRT”), e.g., a table that includes network information for the radio nodes (e.g., neighboring radio nodes and neighbors&#39; neighbors radio nodes) of an enterprise network. 
     Referring to  FIG. 2 , a control point radio node (e.g., radio nodes  12 ,  14 ,  16 ) generates ( 50 ) a NRT as follows. The control point radio node searches ( 51 ) the radio domain and the network domain for neighboring radio nodes, as discussed in further detail below. The control point radio node receives ( 52 ) messages including group identifier information for the neighboring radio nodes. The control point radio node determines ( 53 ) the neighboring radio nodes belonging to the same enterprise network by comparing the group identifier of the neighboring radio nodes to the group identifier of the control point radio node. The control point radio node updates ( 54 ) its NRT with network information for the neighboring radio nodes in the same enterprise network. The control point radio node discovers ( 55 ) its neighbors&#39; neighbors radio nodes by receiving the NRTs of the neighboring radio nodes (“neighboring NRTs”) in the same enterprise network. The neighboring NRTs include network information for the neighbors&#39; neighbors radio nodes, as discussed in further detail below. The control point radio node updates ( 56 ) its NRT with the network information of its neighbors&#39; neighbors radio nodes. 
     Referring to  FIG. 2 , a radio node searches ( 51 ) for neighboring radio nodes in the radio domain and in the network domain, as follows. In the radio domain, a radio node uses a radio interface to “broadcast” its group identifier to other radio nodes. A radio node that broadcasts its group identifier is referred to as a “broadcast radio node.” A radio node may broadcast its group identifier through a broadcast message. A control point radio node receives ( 52 ) (e.g., by intercepting) the broadcast messages to determine the broadcast radio nodes belonging to the same network as the control point radio node. 
     In one particular embodiment, a control point radio node performs REM scans, e.g., when the control point radio node turns on and/or periodically thereafter, to intercept broadcast messages (e.g., SIB#3 messages) of the broadcast radio notes. The broadcast messages include a group identifier (e.g., CSG-Id) of the broadcast radio nodes. By comparing the group identifier of the broadcast radio nodes to the group identifier of the control point radio node, the control point radio node identifies ( 53 ) neighboring radio nodes that belong to the same enterprise network as the control point radio node. When the control point radio node identifies a broadcast radio node that belongs to the same enterprise network, i.e., the CSG-Id of the broadcast radio node matches the CSG-Id of the control point radio node, the control point radio node records the identity and network information of the broadcast radio nodes in its NRT, as described in further detail below. 
     In some embodiments, a control point radio node instructs a handset to search for neighboring radio nodes by sending a message (i.e., an information request message) using a network protocol to the other radio nodes in the enterprise network. The message is broadcast to the radio nodes in the enterprise network. The message includes network information of the control point radio node. A radio node, receiving the message, compares its group identifier to the group identifier included in the message. If the radio node determines that the group identifiers match, the radio node sends the control point radio node a response message indicating that the radio node belongs to the same enterprise network as the control point radio node. 
     In the network domain, a control point radio node searches ( 51 ) for neighboring radio nodes by sending “request messages” (e.g., through use of a Simple Service Discovery Protocol (“SSDP”), UPnP discovery process, and so forth) to radio nodes within the network range of the control point radio node. Because the address (e.g., the Transport Network Layer address) of the other radio nodes is unknown to the control point radio node, the search is a “multicast” search in which requests for network information are simultaneously sent to multiple nodes in the network. Through the search, the control point radio node receives ( 52 ) the unique identifiers of other radio nodes (“discovered radio nodes”) and devices on the network side. The unique identifier may be in the form of an UUID. An example of the UUID format is included in Table 1 below. 
     
       
         
               
             
           
               
                 TABLE 1 
               
               
                   
               
             
             
               
                 Byte Format: [4 bytes]-[4 bytes]-[2 bytes]-[2 bytes]-[2 byte]-[1 byte]- 
               
               
                 [1 byte] 
               
               
                 Content Format: [Cell Identity]-[CSG Id]-[RNC-Id]-[SCTP port]-[PSC]- 
               
               
                 [version]-[reserved] 
               
               
                 Example: 123A324D-67AFB34C-2001-25A0-0072-01-00 
               
               
                   
               
             
          
         
       
     
     The UUID includes network information (e.g., Cell Identity information, CSG-Id information, RNC-Id information, maximum load and current load information, interference and power related information and so forth) that is used by the control point radio node in updating its NRT, as described in further detail below. For example, the UUID includes a “CSG-Id” field, which is used by the control point radio node to identify ( 53 ) neighboring radio nodes associated with the same CSG-Id as the control point radio node. The UUID also includes a “SCTP port” field, which indicates the port through which the control point radio node may establish a connection with a discovered radio node. 
     Additionally, through the search, the control point radio node receives ( 52 ) “discovery messages” (e.g., UDP messages) from the discovered radio nodes. The discovery messages include a uniform resource location (“URL”), from which the control point radio node may retrieve a description of the discovered radio node, and an IP address of the discovered radio node. The IP address of the discovered radio node is used by the control point radio node in communicating with the discovered radio node and is stored in the NRT of the control point radio node. For example, using the IP address of the neighboring radio nodes, the control point radio node requests the NRTs of the neighboring radio nodes, as described in further detail below. 
     Referring back to  FIG. 2 , control point radio node updates ( 54 ) its NRT with network information (e.g., information included in the UUID and the discovery messages) for its neighboring radio nodes. An example NRT is shown below in Table 2. 
     
       
         
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Cell Identity 
                 PSC 
                 CSG-Id 
                 IP address 
                 SCTP port 
               
               
                   
                   
               
             
             
               
                   
                 123456 
                 4 
                 123 
                 104/24 
                 7001 
               
               
                   
                 234567 
                 3 
                 123 
                 102/24 
                 7001 
               
               
                   
                 345678 
                 6 
                 123 
                 103/24 
                 7001 
               
               
                   
                   
               
             
          
         
       
     
     A NRT includes cell identity information, PSC information, CSG-Id information, IP address information and SCTP port information. The cell identity includes an identifier of a radio node that was discovered from radio scanning (e.g., REM) and also from a UUID received from the network through the discovery process. CSG-Id designates a group, e.g., enterprise, to which a radio node belongs. PSC designates a physical identity of a radio node. The IP address field includes a radio node&#39;s IP address. The SCTP port field includes a number that defines a communications port of a radio node. A radio node stores its NRT and updates its NRT, for example, during a scheduled and/or “periodic” REM scan or when another neighboring radio node is discovered. 
     Still referring back to  FIG. 2 , the control point radio node discovers ( 55 ) its neighbors&#39; neighbors by receiving the NRTs of its neighboring radio nodes (i.e., neighboring NRTs). Through the network information included in the neighboring NRTs, the control point radio node “sees” (i.e., identifies) other radio nodes that are not otherwise “visible” (e.g., are outside the radio range and/or the network range) to the control point radio node. The control point radio node builds  56  a comprehensive mapping of the radio nodes belonging to the same enterprise network as the control point radio node by adding ( 56 ) the neighboring NRTs to the NRT of the control point radio node. 
     In one particular embodiment, radio node  12  ( FIG. 1 ) is a control point radio node. Through radio and/or network searching, radio node  12  discovers radio node  14  and receives the UUID of radio node  14 . Using the SCTP-port information included in the UUID of radio node  14 , radio node  12  establishes a SCTP connection with radio node  14 . Based on the information included in the UUID of radio node  14  and the discovery messages received from radio node  14 , radio node  12  updates its NRT with the network information associated with radio node  14 . Radio node  14  also updates its NRT with the network information associated with radio node  12 . 
     Through the connection, radio node  12  and radio node  14  exchange NRTs. Radio node  12  receives the NRT of radio node  14 . Radio node  14  receives the NRT of radio node  12 . Radio node  12  updates its NRT with the network information included in the NRT of radio node  14 . Radio node  14  updates its NRT with the network information included in the NRT of radio node  12 . 
     Through the SCTP connection, radio node  12  receives “heart beat” messages from radio node  14 . The heart beat messages indicate the existence of a connection between radio node  12  and radio node  14 . When radio node  12  stops receiving heart beat messages from radio node  14 , radio node  12  removes radio node  14  and the neighboring radio nodes of radio node  14  from its NRT. Radio node  12  also removes radio node  14  and the neighboring radio nodes of radio node  14  from its NRT when a subsequent REM scan indicates that radio node  14  has been deactivated. 
     Referring to  FIG. 3 , an example of a self-discovered enterprise network  60  is shown. The network  60  includes radio nodes  62 ,  64 ,  66 ,  68 ,  70 ,  72 ,  74 ,  76 ,  78 ,  80 ,  82  having different scrambling codes and IP addresses. The radio nodes  62 ,  64 ,  66 ,  68 ,  70 ,  72 ,  74 ,  76 ,  78 ,  80 ,  82  are associated with the same CSG-Id, belong to the same enterprise network, and are connected to each other through communication links (e.g., Iux links). Through radio scanning and network searching, radio node  62  locates neighboring radio nodes  64 ,  66 ,  68  and updates its NRT with the network information associated with the neighboring radio nodes  64 ,  66 ,  68 . 
     Referring to  FIG. 4 , an example NRT  90  is shown. The NRT includes columns  91 ,  93 ,  95 ,  97 ,  99  corresponding to various types of network information (e.g., cell identity information, PSC information, gateway node information, SCTP port information and destination IP information). Entries  92 ,  94 ,  96  correspond to the network information associated with neighboring radio nodes  64 ,  66 , and  68 . As new radio nodes cells are added to the network, radio node  62  discovers more neighboring radio nodes and updates its NRT accordingly. 
     Referring back to  FIG. 3 , radio node  62  receives over a communication link (e.g., an Iux link) the NRT of neighboring radio node  64 . The NRT of neighboring radio node  64  includes network information associated with radio nodes  76 ,  78  and  80  (i.e., the neighbors&#39; neighbors radio nodes). Through the NRT of neighboring radio node  64 , radio node  62  learns of neighbors&#39; neighbors radio nodes  76 ,  78  and  80 . Radio node  62  updates its NRT with the network information associated with neighbors&#39; neighbors radio nodes  76 ,  78  and  80 . In  FIG. 4 , entries  98 ,  100  and  102  correspond to the network information associated with neighbors&#39; neighbors radio nodes  76 ,  78  and  80 . 
     Radio node  62  receives the NRT of neighboring radio node  68 , which includes network information associated with neighbors&#39; neighbors radio nodes  70 ,  72  and  74 . In  FIG. 4 , entries  104 ,  106  and  108  correspond to the network information associated with neighbors&#39; neighbors radio nodes  70 ,  72  and  74 . Radio node  62  also receives the NRT of neighboring radio node  66 , which includes network information associated with neighbors&#39; neighbor radio node  82 . In  FIG. 4 , entry  110  corresponds to the network information associated with neighbors&#39; neighbor radio node  82 . 
     Referring to  FIGS. 5A-5D , an example of a handover process in a communications network  120  is shown. The communications network includes a gateway  124  (HNB-GW) and radio nodes  62 ,  64 ,  76  (see also  FIG. 3 ). Referring to  FIG. 3 , radio node  64  is a neighboring radio node of radio node  62  and radio node  76  is a neighbors&#39; neighbor radio node of radio node  62 . Radio nodes  62 ,  64 ,  76  are connected to gateway  124  through Iuh interface links  126 ,  127 ,  129 . Radio nodes  62 ,  64 ,  76  are connected to each other through Iux interface links  128 ,  131 . 
     Referring to  FIG. 5A , a handset  122  is connected to radio node  62  through an active communication link (not shown). Handset  122  moves from radio node  62  towards neighboring radio node  64 . Referring to  FIG. 5B , to maintain a communication on the handset  122 , radio node  62  retrieves from its NRT network information for neighboring radio node  64  and sets up a soft handover link  130  (which may also be link  128 ) to the neighboring radio node  64 . Through the soft handover link  130 , the handset communicates with both radio node  62  and neighboring radio node  64  over communication links  121 ,  123 . Radio node  62  retains control of the communication during and/or after the soft handover, because radio node  62  is acting as a control point radio node. 
     Referring to  FIG. 5C , the handset  122  moves away from neighboring radio node  64  toward neighbors&#39; neighbor radio node  76 . Radio node  62  acts as a control point radio node and retrieves from its NRT the network information for radio node  76  to establish a link  134  with neighbors&#39; neighbor radio node  76 . Through the link  134 , radio node  62  initiates a hard handover to neighbors&#39; neighbor radio node  76 . In the hard handover, the call gets physically relocated to radio node  76 . Referring the  FIG. 5D , the handover finishes when the handset  122  attaches itself to radio node  76  through link  136 . 
     The techniques described herein can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The techniques can be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network. 
     Method steps of the techniques described herein can be performed by one or more programmable processors executing a computer program to perform functions by operating on input data and generating output. Method steps can also be performed by, and apparatus can be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). Modules can refer to portions of the computer program and/or the processor/special circuitry that implements that functionality. 
     Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in special purpose logic circuitry. 
     To provide for interaction with a user, the techniques described herein can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer (e.g., interact with a user interface element, for example, by clicking a button on such a pointing device). Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. 
     The techniques described herein can be implemented in a distributed computing system that includes a back-end component, e.g., as a data server, and/or a middleware component, e.g., an application server, and/or a front-end component, e.g., a client computer having a graphical user interface and/or a Web browser through which a user can interact, or any combination of such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), e.g., the Internet, and include both wired and wireless networks. 
     The computing system can include clients and servers. A client and server are generally remote from each other and typically interact over a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. 
     The term “machine-readable storage media” is not meant to encompass non-statutory subject matter as defined at the time the attached claims are construed. The term “machine-readable storage media”, however, is meant to cover any subject matter which is defined as statutory at the times the claims are construed. 
     A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made and therefore other embodiments are within the scope of the following claims. 
     For example, techniques described herein may be implemented using CDMA (wideband and/or narrow band) and non-CDMA air interface technologies, as well as the 1xEV-DO air interface standard. Additionally, a radio node may update its NRT with information received from other devices, for example, a handset. The radio node may receive measurement reports from a handset indicating PSC and possible cell identities of neighboring radio nodes. The radio node updates its NRT using the measurement reports and the discovery messages from the neighboring radio nodes. 
     In another example, a first radio node that is deployed in an enterprise network is not a control point radio node and will not be able to discover other enterprise radio nodes in the area. In this example, the discovery process begins when a control point radio node joins the enterprise network.