TITLE OF THE INVENTION:

NETWORK ELEMENT AUTO-DISCOVERY IN A WIRELESS

BROADBAND NETWORK

CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present invention is related to, claims the priority of, and incorporates in its entirety by reference U.S. Provisional Patent Application No. 60/877,617, filed December 29, 2006.

BACKGROUND OF THE INVENTION: Field of the Invention:

[0002] The present invention relates to wireless communications and radio network technology. More specifically, the present invention relates to automatic procedures for network configuration of a wireless broadband network such as, for example, a Worldwide Interoperability for Microwave Access (WiMAX) or Long Term Evolution (LTE) network.

Description of the Related Art:

[0003] Wireless communications and radio network technology has undergone a number of changes since its initial inception. One emerging variety of wireless communication and radio network technology is the system known as Worldwide Interoperability for Microwave Access (WiMAX), which is typically considered to be related to the present generation of Institute of Electrical and Electronics Engineers (IEEE) 802.16 (including, for example, 802.16a and 802.16c).

[0004] However, these standards do not define any automatic procedure for network configuration. Thus, conventionally, everything in the system has to be configured manually. Every base station (BS) has to be configured with all neighboring BSs for R8 connectivity and with all serving access service network gateways (ASN-GW) for R6 connectivity. Eveiy ASN-GW should

be configured with hundreds of neighboring BSs, ASN-GWs, home agents (HA), and authentication and authorization servers (AAA).

SUMMARY OF THE INVENTION

[0005] One embodiment of the present invention can be an apparatus. The apparatus can include a sender module configured to send a first broadband wireless apparatus advertisement as a broadcast or multicast message. The apparatus can also include a receiver module configured to receive a second broadband wireless apparatus advertisement from another apparatus. The sender module can be configured to send a third broadband wireless apparatus advertisement to the another apparatus as a unicast message. [0006] One embodiment of the present invention can be an apparatus. The apparatus can include sender means for sending a first broadband wireless apparatus advertisement as a broadcast or multicast message. The apparatus can also include receiver means for receiving a second broadband wireless apparatus advertisement from another apparatus. The sender means can be configured to send a third broadband wireless apparatus advertisement to the another apparatus as a unicast message.

[0007] One embodiment of the present invention can be a method. The method can include sending a first broadband wireless network element advertisement as a broadcast or multicast message. The method can also include receiving a second broadband wireless network element advertisement from another network element. The method can further include sending a third broadband wireless network element advertisement to the another network element as a unicast message.

[0008] One embodiment of the present invention can be a computer program embodied on a computer readable medium and encoding instructions for performing a method. The method can include sending a first broadband wireless network element advertisement as a broadcast or multicast message. The method can also include receiving a second broadband wireless network

element advertisement from another network element. The method can further include sending a third broadband wireless network element advertisement to the another network element as a unicast message.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0009] For proper understanding of the invention, reference should be made to the accompanying drawings.

[0010] Figure 1 presents a WiMAX network diagram.

[0011] Figure 2 illustrates a network element advertisement extension in accordance with an embodiment of the present invention.

[0012] Figure 3 illustrates a network element according to an embodiment of the present invention.

[0013] Figure 4 illustrates a method in accordance with an embodiment of the present invention.

[0014] Figure 5 illustrates a network element advertisement extension in accordance with another embodiment of the present invention.

[0015] Figure 6 provides an example embodiment of a network in which certain embodiments of the present invention can be implemented.

DETAILED DESCRIPTION OF EMBODIMENTS:

[0016] An example embodiment of the present invention can be implemented in a Worldwide Interoperability for Microwave Access (WiMAX) network, which is made up of multiple network elements (NE) as shown in Figure 1.

Although, for convenience sake, embodiments of the present invention are often described with relation to WiMAX below, it should be understood that the present invention is not limited by the examples provided. Thus, while the present invention may be beneficially to WiMAX, it is not necessarily limited thereto.

[0017] As can be seen in Figure 1, major network elements can include a Base

Station (BS), an Access Service Network Gateway (ASN-GW), a Home Agent

(HA), and an Accounting, Authentication and Authorization Server (AAA). [00 IS] As shown in Figure 1, a WiMAX network can be created with an hierarchical architecture. Thus, a set of BSs are connected to an ASN-GW using interface known as a logical R6 Reference Point. Likewise, ASN-GWs are interconnected using logical R4 Reference Point and HA/AAA are connected to ASN-GWs using logical R3 Reference Point. [0019] Every BS can be connected to multiple ASN-GWs concurrently, which adds complexity to the overall architecture. ASN-GWs can also be interconnected with complex R4 connectivity. The R4 connectivity can range from pure chain connectivity to full mesh connectivity and can encompass everything in between those types of connectivity.

[0020] ASN-GWs can be connected to none, some, or all of the HAs and AAAs. There can also be another interface. This interface can be between BSs and can be referred to as an R8 Reference Point.

[0021] In some embodiments, a single network element can include multiple WiMAX entities, which makes the analysis of the network more complicated. One reason that a single network element can include multiple WiMAX entities is that WiMAX entities are typically defined by function, leaving the precise physical implementation up to the manufacturers. [0022] In one example embodiment, WiMAX Network Working Group (NWG) profile B defines a so-called flat architecture in which a single NE can include both BS and ASN-GW functionalities. Thus, WiMAX NWG profile B can be, in some ways, similar to Internet high-speed packet access (I- HSPA), in that it can flatten or simplify network access from a mobile device. [0023] Figure 6 provides an example embodiment of a network in which certain embodiments of the present invention can be implemented. As shown in Figure 6, an Access Service Network (ASN) shown on the left side of the figure, and a Connectivity Service Network (CSN) can work together to provide services to, for example, mobile stations (MSS). [0024] The MSS can interact with a base station (BS) functionality through a

reference point Rl. Rl can include a set of protocols and procedures between MSS and the ASN as per the air interface (including the physical layer (PHY) and the media access control layer (MAC)) specifications from Institute of Electrical and Electronics Engineers (IEEE) 802.16. Rl can also include additional protocols related to the management plane.

[0025] Another reference point R2 (not explicitly shown in Figure 6, but can be seen, for example, in Figure 1), can include protocols an procedures between the MSS and the CSN associated with tasks of authentication, services authorization, and internet protocol (IP) host configuration. [0026] A third reference point R3 (shown as R3a and R3b) can include a set of control plane and bearer plane protocols for internetworking between ASN and CSN. The bearer plane can include IP tunnels between the ASN and CSN. The control plane can include protocols for IP tunnel establishment and release control in accordance with the MSS mobility events. The control plane also includes the protocols for authentication, authorization, and accounting (AAA), policy, and quality of service (QoS) enforcement coordination between the ASN and CSN.

[0027] A fourth reference point R4 (shown as R4a and R4b) can include a set of control plane and bearer plane protocols that coordinate inter- ASN GW mobility.

[0028] A fifth reference point R5 (not shown) can include a set of control plane and bearer plane protocols for internetworking between the CSN operated by the home network service provider (NSP) and that operated by a visited NSP. The bearer plane can include IP tunnels between the CSN operated by the home NSP and that operated by the visited NSP. The control plane can include protocols for IP tunnel establishment and control in accordance with the MSS mobility events (handovers). In addition, the control plane can include the protocols for AAA and policy coordination between the CSN operated by the home NSP and that operated by the visited NSP. [0029] A sixth reference point R6 (shown as R6a and R6b) can include a set of

control and bearer plane protocols for internetworking between the BS and the ASN GW. The bearer plane can include tunnels between the BS and the ASN GW. The control plane can include protocols for IP tunnel establishment and release control in accordance with the MSS mobility events. The control plane can also include protocols for, for example, AAA, bandwidth brokering, or policy coordination in the BS as well as other protocols for, for example, radio resource management and the like.

[0030] A seventh reference point R7 can include an optional set of control plane protocols for coordination between the two groups of functions. [0031] Finally, an eighth reference point R8 can include a set of control and bearer plane protocols for internetworking between the Base Stations in order to ensure fast and seamless handover. The bearer plane can include protocols that allow data transfer between base stations involved in handover of a certain MS. The control plane can include inter-BS communication protocols and an additional set of protocols that allow controlling the data transfer between the base stations involved in the handover of a certain MS. [0032] Certain embodiments of the present invention provide mechanisms for automatically configuring network element interconnections. Thus, in certain embodiments of the present invention, conventional manual configuration of a broadband wireless network, such as WiMAX, can be obviated. [0033] Accordingly, in an embodiment of the present invention, every BS in the network can be configured with all neighboring BSs for R8 connectivity automatically. Likewise, in an embodiment of the present invention, every BS can be automatically configured with all serving ASN-GWs for R6 connectivity.

[0034] In certain embodiments of the present invention, every ASN-GW can, automatically, be configured with all served BSs for R6 connectivity, and, thus, each ASN-GW can support hundreds of BSs. Likewise, another embodiment of the present invention can automatically configure every ASN- GW with all neighboring ASN-GWs for R4 connectivity. This automatic

configuration could result in a veiy large number of connections in a full mesh configuration.

[0035] Furthermore, in some embodiments of the present invention, every ASN-GW can be configured with all HAs and AAAs.

[0036] Accordingly, by the use of automatic configuration, the significant and tedious conventional manual network configuration can be reduced, minimized, or avoided. Furthermore, a certain amount of otherwise necessary synchronization between different NEs may be avoided or reduced. [0037] Furthermore, problems caused by misconfiguration due, for example, to human error due to the tediousness and complexity of the task may be reduced. Therefore, certain embodiments of the present invention may ameliorate some of the problems with conventional broadband wireless access networks such as WiMAX.

[0038] Certain embodiments of the present invention may implement automatic configuration using a mechanism that is similar to RFC3344. This mechanism, however, may be used for the discovery of network elements in a broadband wireless access network, such as a WiMAX network. [0039] In some embodiments, the automatic configuration can be provided using Internet Control Message Protocol (ICMP) router discovery combined with an extension that is specific to a broadband wireless access network, such as a WiMAX-specific extension. In other embodiments, a similar extension can be used with different transport, for example, user datagram protocol (UDP) (in one embodiment with a WiMAX reserved port and corresponding WiMAX header) or any other transport protocol, such as transmission control protocol (TCP) or streaming control transmission protocol (SCTP). [0040] Using automatic configuration implemented in this way, the amount of manual configurations in broadband wireless access network elements, such as WiMAX network elements, can be significantly reduced. Thus, the disclosed scheme can significantly reduce the amount of manual configurations in, for example, WiMAX network elements.

[0041] More specifically, in certain embodiments of the present invention, WiMAX NE auto-discovery can be implemented to run on top of ICMP router discovery, which is described in more detail in RFC 1256. The WiMAX NE auto-discovery can also include a broadband wireless access network element advertisement extension, such as a WiMAX network element advertisement extension. In other embodiments, a similar extension can be used with a different transport protocol, such as, for example, UDP (in one embodiment with a WiMAX reserved port and corresponding WiMAX header) or any other transport protocol, such as, for example, TCP or SCTP. [0042] Network element advertisements, such as WiMAX network element advertisements, can be sent using the sending network element's internet protocol (IP) address as a source and either an "all systems on this link" multicast address (for example, 224.0.0.1) or a broadcast address (for example, 255.255.255.255) as a destination.

[0043] In addition, network element advertisements, such as WiMAX network element advertisements, can be sent with a unicast address. Naturally, such address would need to be known somehow. Knowledge of the unicast address could be obtained either from prior configuration or from a previously received network element advertisement, such as another WiMAX Network Element Advertisement.

[0044] In some embodiments, a newly added network element would be configured to advertise itself to the network using a multicast or broadcast IP address. In contrast, existing network elements would, in such embodiments, advertise themselves to the newly added network element using the unicast address listed as the source address in the network element's own multicast/broadcast network advertisement packet.

[0045] In a particular embodiment, in order to eliminate a need for a solicitation request, it can be mandated to send a network element advertisement, such as a WiMAX network element advertisement, when a network element advertisement (such as a WiMAX network element

advertisement) is received from a previously unknown network element. [0046] A network element, such as a WiMAX NE, could have a separate user plane and control plane, with corresponding separate IP addresses. To accommodate such a case, certain embodiments of the present invention can include all user plane IP addresses in a standard ICMP portion of the packet in a "Router Address(es)" field. In other embodiments similar information can be provided on top of UDP or other transport protocol (such as, for example, TCP, SCTP, and the like) as shown in Figure 5.

[0047] If the NE doesn't have a user plane component (such as, for example, the ASN-GW C-Plane shown in Figure 1), the ICMP message "Num Addrs" field can be set to zero. Otherwise, the ICMP "Num Addrs" field can be set to the number of addresses provided in the "Router Address(es)" field. In other embodiments similar information can be provided on top of UDP or another transport protocol (such as, for example, TCP, SCTP, or the like) as shown in Figure 5 by field "Num User Plane Addresses" and corresponding "zero or more User Plane Addresses."

[0048] All control plane IP addresses can be specified using a broadband wireless network element advertisement extension, such as a WiMAX network element advertisement extension. An example of such an advertisement extension is shown in Figure 2.

[0049] As can be seen from Figure 2, the fields of the extension can include: [0050] Type - The content of this field be a suitable type indication. The precise content of this field may be standardized in the future. [0051] Length - The content of this field may be a value, (6 + 4*N), in which 6 accounts for the number of bytes in the Sequence Number, Registration Lifetime, flags, and reserved fields, and N is the number of Control Plane addresses advertised.

[0052] Sequence Number - The content of this field can be a number of network element advertisement messages, such as WiMAX network element advertisement messages, sent since the start of the network element. NE can

start sending its advertisement messages with the Sequence Number equal to zero. Each advertisement message cab then be sent with Sequence Number equal to the previous Sequence Number incremented by one. [0053] An exception to the incremental increase of the value for Sequence Number can be in a rollover case. In the rollover case, the number Oxffff (or any other suitable maximum value) can be followed by a predetermined nonzero value, such as, for example, number 0x100. The use of the predetermined non-zero number can help to differentiate between a start (or restart) and rollover. Thus, in such embodiments, receiving the Sequence Number set to zero for a known NE could suggest that this NE was restarted for some reason. For example, receiving the Sequence Number set to zero for a known NE can indicate that the NE has experienced a change, such as a change in IP address or a change in configuration. For example, the NE could have added or divested a network functionality such as home agent (HA) functionality. Thus, the network element could send out an initial advertisement every time there is a change or restart, in addition to being sent out when the network element is started.

[0054] Registration Lifetime — The content of this field can be the time in seconds that this element should be kept listed as a valid network element (for example, a WiMAX NE) in tables of other network elements. In certain embodiments, the value of OxFFFF, or another predetermined value, can be used to indicate infinity (i.e. that the element should be kept listed as a valid network element indefinitely). The network element can be configured to send out a new advertisement message at a predetermined time in order to refresh the validity of the network element's listing, in the case that the time period of validity is not infinite.

[0055] H - This field can be a flag that indicates Home Agent (HA) functionality. In certain embodiments, if Home Agent functionality is included in this NE the field can be set to one, otherwise it can be set to zero. [0056] A - This field can be a flag that indicates authentication and

authorization server (AAA) functionality. In certain embodiments, if AAA server functionality is included in this NE the field can be set to one, otherwise it can be set to zero.

[0057] B - This field can be a flag that indicates Base Station (BS) functionality. In certain embodiments, if Base Station functionality is included in this NE the filed can be set to one, otherwise it can be set to zero.

[0058] G - This field can be a flag that indicates access service network gateway (ASN-GW) functionality. In certain embodiments, if ASN-GW functionality is included in this NE the field can be set to one, otherwise it can be set to zero

[0059] N - This field can be a flag that indicates busy/overload flag. In certain embodiments, the meaning of this flag being set to a true value (such as, for example, one) can be that this NE should not be used for any new connections.

[0060] r - This field can be a reserved bit.

[0061] Control Plane Addresses - This field can provide a listing of the IP addresses used for control plane. In some embodiments, if the same address is used for both user plane and control plane, provision of the control plane IP address can be omitted. In general, however, at least one address (either for user plane or for control plane) should be provided in the advertisement message.

[0062] Figure 3 illustrates an embodiment of the present invention, which can be a network element 300. The network element 300 can include a sender module 310 configured to send a first broadband wireless network element advertisement as a broadcast or multicast message. The network element 300 can also include a receiver module 320 configured to receive a second broadband wireless network element advertisement from another network element (not shown). The sender module 310 can be configured to send a third broadband wireless network element advertisement to the another network element as a unicast message.

[0063] The network element 300 can also include a processor 330 configured

to process signals and information, and provide instructions to the sender module 310 and receiver module 320. The network element 300 can additionally include a communication device, such as antenna 340, for communicating with other network elements.

[0064] The processor 330 can be implemented as a computer that includes a computer readable medium encoding instructions for performing a method. The processor 330 can take the form, for example, of a general purpose computer or an application specific integrated circuit. The processor 330 can be provided with suitable interfaces for communicating external to the network element 300 and for interacting with a local memory include caches, tables, and the like. The sender module 310 and the receiver module 320 can be implemented in hardware, software, or a hybrid of hardware and software. [0065] The sender module 310 can be configured to broadcast the first advertisement to a broadcast internet protocol address. The sender module 310 can alternatively or additionally be configured to multicast the first advertisement to a multicast internet protocol address. The sender module 310 can also be configured to unicast the third advertisement to a previously known internet protocol address. The previously known internet protocol address can be determined by the processor 330 from information contained in the second advertisement.

[0066] The network element 300 can be configured to provide the third advertisement in response to the second advertisement when an address in the second advertisement indicates that the another network element was previously unknown. Whether the another network element was previously unknown can be determined by the processor 330, which may compare the source address in the advertisement message with a table contained in a memory (not shown) of the network element 300. Alternatively or additionally, the network element 300 can be configured to provide the third advertisement in response to a solicitation request. [0067] The first advertisement can be configured to include a type field, a

length field, a sequence number field, a registration lifetime field, flags, a number of control plane addresses advertised, and the control plane address(es), if any. The first advertisement can also include one or more reserved bits. The processor 330 can be configured to prepare the first advertisement based on data stored in a portion of memory, such as a configuration table, of the network element 300.

[0068] The first advertisement can be configured to include a user plane address of the network element 300 in a router address field of a portion of an internet control message protocol packet. Of course, the network element 300 may not have a user plane address, particularly if the network element 300 is an ASN-GW control plane.

[0069] The length field can be configured to indicate a value that is 6 + 4 * N bytes, wherein N represents the number of control plane addresses advertised. The sequence number field can be configured to indicate the number of broadband wireless network element advertisements sent since the start of the network element 300. The sequence number can be configured to be a predetermined value to indicate a rollover, and the predetermined value can be a value other than zero.

[0070] The registration lifetime field can be configured to indicate the time in seconds that the network element 300 should be considered valid based on the advertisement. The registration lifetime field is configured to a predetermined value for infinite. The processor 330 of the network element 300 can be configured to update a registration table in the memory of the network element 300 in accordance with the data found in the registration lifetime field. This step may be performed any time a network element advertisement message is received.

[0071] The flags in the advertisement message can be configured to indicate functionality of the network element 300. The functionality of the network element 300 can be at least one of a base station, an access service network gateway, a home agent, or an authentication and authorization server.

[0072] Figure 4 is a flow chart of a method according to an embodiment of the present invention. As shown in Figure 4, the method can include sending 410 a first broadband wireless network element advertisement as a broadcast or multicast message. The method can also include receiving 420 a second broadband wireless network element advertisement from another network element. The method can further include sending 430 a third broadband wireless network element advertisement to the another network element as a unicast message.

[0073] The method can include broadcasting the first advertisement to a broadcast internet protocol address. The method can, alternatively, include multicasting the first advertisement to a multicast internet protocol address. The method can include unicasting the third advertisement to a previously known internet protocol address. The method can include obtaining the previously known internet protocol address from the second advertisement. [0074] The sending 430 the third advertisement can be performed in response to the second advertisement when an address in the second advertisement indicates that the another network element was previously unknown. Alternatively, the sending 430 the third advertisement can be performed in response to a solicitation request.

[0075] The method can include configuring the first advertisement to include a type field, a length field, a sequence number field, a registration lifetime field, flags, a number of control plane addresses advertised, and the control plane address(es), if any. The method can also include configuring the first advertisement to include a user plane address in a router address field of a portion of an internet control message protocol packet. [0076] The method can include configuring the length field to indicate a value that is 6 + 4 * N bytes, wherein N represents the number of control plane addresses advertised. The method can also include configuring the sequence number field to indicate the number of broadband wireless network element advertisements sent since the start of the network element. The method can

further include configuring the sequence number to a predetermined value for a rollover, wherein the predetermined value is not zero. [0077] The method can include configuring the registration lifetime field to indicate the time in seconds that the network element should be considered valid based on the advertisement. The method can also include configuring the registration lifetime field to a predetermined value for infinite. The method can further include configuring the flags to indicate functionality of the network element. The method can additionally include providing a reserved bit in the first advertisement message.

[007S] The method can be configured to be performed in at least one of a base station, an access service network gateway, a home agent, or an authentication and authorization server.

[0079] One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.