Method and apparatus for end node assisted neighbor discovery

ES 2 346 696 T3

DESCRIPTION

Procedure and apparatus for end-node-assisted neighbor discovery.

Field of the invention

The present invention relates to a communication system and more particularly to methods and apparatus for routing messages based on physical layer information in wireless communication networks, eg cellular. Background of the invention

The Open Systems Interconnection (OSI) reference model is useful in explaining various routing and communications operations. The OSI reference model includes 7 layers with the application layer being the highest layer and the physical layer being the lowest layer. The physical layer is the layer that handles the actual physical connections and attributes of the physical connections in the system. On top of the physical layer is a data link layer, sometimes called the link layer. The link layer (layer 2 in the OSI model) is sometimes described as a specific technology transfer layer. Above the link layer is the network layer (OSI layer 3) in which network routing and retransmission is supported. The network layer is sometimes called the packet layer. It is at the network layer where the routing of messages / packets is carried out through the network, for example, in one or more paths. Different addressing can be used to direct messages and signals at different levels. For example, a network address such as an IP address can be used to route messages / packets at the network layer level. MAC addresses can be used to control the routing of messages at the data link layer level. At the lowest level of the OSI model, the physical level, one or more physical identifiers have a relationship to an actual physical attribute or characteristic of a source or destination device. An understanding of the different communication layers and the different addressing techniques used for each of the layers will facilitate an understanding of the present invention.

Communication systems often include a plurality of network nodes that are coupled to access nodes through which end nodes, eg mobile devices, are coupled to the network. Network nodes can be arranged in a hierarchy. Typically the end nodes communicate with the access nodes directly through connections that have been established with those access nodes. Such systems typically rely on the existence of a two-way communication link between an access node and an end node to support two-way communications between an end node and an access node. Note that in such systems the end node does not normally know the network layer address of a target destination access node but may have knowledge of information that it can receive over broadcast channels which may normally include a physical layer identifier which normally they are not used in such systems for routing messages. This approach results in handover delays and packet loss when the end node can only maintain a single bidirectional communication link at the time.

It should then be appreciated that there is a need for methods and apparatus that allow an end node that does not have any current uplink communications link to a target access node to communicate with said target access node through another access node. access with which the end node has a current uplink communication link even when said end node does not know the network address of the target access node.

In some systems, end nodes can maintain multiple two-way communication links with different access nodes at the same time. However, such systems typically require the end nodes to send messages intended for a specific access node, with which an end node has a connection, over the link that is directly connected to that specific access node. This approach, in some cases, is ineffective since links, especially when they are wireless links, tend to fluctuate in quality (eg delay and loss characteristics). As a result, the link to the target destination access node may not be the best link available to the end node at the time it is necessary to send a message to said target destination access node. Typically this limitation is overcome by resorting to network layer communications that can be routed through multiple hops due to the use of network layer addresses (eg, IP addresses). This approach of using network layer addresses is also ineffective especially when messaging is related to specific link layer functions, since network layer messages tend to be much larger than link layer messages on some systems. . Such ineffective signaling is not well suited for resource constrained air link communications.

Access nodes serving neighboring geographic cells are typically known to each other through manual configuration. During such a configuration, various parameters are configured on an access node corresponding to several of its neighbors. Such a configuration is normally labor intensive and error prone not only due to possible human error, but also due to the fact that the network design of a wireless network often changes due to network expansion or even due to environmental conditions. . This is particularly relevant for a gradual phased implementation of a wireless communication system. It should then be appreciated that there is a need for end-node-assisted neighbor discovery processes so that access nodes can exchange neighbor information in response to end-node signaling, as end-nodes move through the network. system and find newly deployed nodes, rather than through manual configuration techniques.

Additional attention is paid to US2004 / 0166857, which refers to security mechanisms that protect the integrity of candidate access node discovery procedures in a mobile communication network. An access node stores information about candidate access nodes in the mobile communication network and updates the information only after verifying the information.

ES 2 346 696 T3 provided by a mobile terminal after handover from one access node to another access node. Information on candidate access nodes in the mobile communication network can also be associated with a particular mobile terminal and stored in the mobile terminal in a list of candidate access nodes.

Summary of the invention

According to the present invention, there is provided a method of operating a wireless terminal, as set forth in claim 1, and a wireless terminal, as set forth in claim 14. Further embodiments are claimed in the dependent claims.

The present invention relates to, among other things, a method of using end nodes, for example wireless terminals, to discover base stations and communicate information about discovered access nodes, for example base stations, to other nodes of access in a system. Thus, various embodiments of the present invention relate to wireless terminal-based methods of supporting neighbor discovery in a communication system that includes a plurality of access nodes. As the wireless terminal roams the system and new access nodes are found, one or more physically adjacent access nodes will be informed of the presence of the new access node as a result of communications with the wireless terminal.

In some, but not necessarily all implementations, an access node failure is used to route a message from one end node to another access node to activate various signals used to provide updated routing information to the access node that could not complete the routing operation. In this way, an access node can update its routing information to include routing information corresponding to access nodes that were encountered by an end node but of which the access node was previously unaware or lacked routing information. adequate.

By automating all or part of the access node discovery process, the procedures and apparatus of the present invention make phased implementation of access nodes easier than in systems where access nodes must be programmed manually. and / or be supplied with information about your neighbors as part of the process of implementing a new base station. Furthermore, since the neighbor discovery and update process takes place with little or no direct involvement of the administrator, the methods and apparatus of the present invention are particularly well suited for systems where the entire network may not be under control. single administrator and individuals can freely add access nodes, e.g. base stations, at will, without first notifying other base station administrators of the introduction of a new base station in the system.

Therefore, various features of the invention relate to end node procedures for receiving signals from access nodes that indicate an identifier for an access node address resolution failure and cause said end node to send access messages. neighbor notification for the establishment of new access node neighbors.

While some features relate to a wireless terminal apparatus and procedures, as well as novel messages of the invention stored in a wireless terminal, other features relate to novel access node apparatus and procedures. The invention also relates to data storage devices, eg memory devices, that store one or more of the novel messages of the present invention.

Although various embodiments have been discussed in the summary above, it should be appreciated that not all embodiments necessarily include the same features and some of the features described above are not necessary but may be desirable in some embodiments. Numerous additional features, embodiments, and benefits of the present invention are discussed in the detailed description below.

Brief description of the drawings

Figure 1 illustrates a network diagram of an exemplary communication system implemented in accordance with the present invention.

Figure 2 illustrates an exemplary end node implemented in accordance with the present invention.

Figure 3 illustrates an exemplary access node implemented in accordance with the present invention.

Figure 4 illustrates an exemplary connection identifier implemented in accordance with the present invention.

Figure 5 illustrates an exemplary message using the connection identifier of Figure 4 implemented in accordance with the present invention.

Figure 6 illustrates an exemplary design signaling performed when an end node maintains a bidirectional connection with an access node and wants to communicate with another access node.

Figure 7 illustrates exemplary design signaling performed when an end node maintains bidirectional connections with multiple access nodes.

Figure 8 illustrates an exemplary signaling performed in accordance with the present invention when an end node triggers a neighbor discovery process between two access nodes.

Figure 9 illustrates an exemplary PID for a top-level address resolution table that can be used to map between (to / from) PIDs and corresponding top-level addresses.

Detailed description

The methods and apparatus of the present invention for routing messages based on physical layer information, eg, physical layer identifiers, which can be used to support communication sessions with one or more end nodes, eg, mobile devices. The method and apparatus of the invention can be used with a wide range of communication systems. For example, the invention can be used with systems that support mobile communication devices such as modem-equipped laptop computers, PDAs, and a wide variety of other devices that support wireless interfaces for better device mobility.

Figure 1 illustrates an exemplary communication system 100 implemented in accordance with the present invention.

ES 2 346 696 T3 tion, for example, a cellular communication network, comprising a plurality of nodes interconnected by communication links. Exemplary communication system 100 is, for example, a spread spectrum multiple access orthogonal frequency division multiplexing (OFDM) wireless communication system. Nodes in exemplary communication system 100 exchange information using signals, eg, messages, based on communication protocols, eg, Internet Protocol (IP). The communication links of the system 100 can be implemented, for example, using wires, fiber optic cables, and / or wireless communication techniques. The exemplary communication system 100 includes a plurality of end nodes 144, 146, 144 ', 146', 144 ", 146", which access the communication system through a plurality of nodes 140, 140 ', 140 "of access. The end nodes 144, 146, 144 ', 146', 144 ", 146" can be, for example, terminals or wireless communication devices, and the access nodes 140, 140 ', 140 "can be, for example, base stations. Base stations can be implemented as wireless access routers. The exemplary communication system 100 also includes a series of other nodes 104, 106, 110, and 112, used to provide interconnectivity or to provide specific services or functions. Specifically, the exemplary communication system 100 includes a server 104, used to support the transfer and storage of state belonging to the end nodes. The server node 104 may be, for example, an AAA server, or it may be a context transfer server, or it may be a server that includes both AAA server functionality and context transfer server functionality.

The exemplary system 100 of FIG. 1 depicts a network 102 that includes the server 104 and node 106, which are connected to an intermediate network node 110 via a corresponding network link 105 and 107, respectively. Intermediate network node 110 in network 102 also provides interconnectivity to network nodes that are external from the perspective of network 102 through network link 111. Network link 111 is connected to another intermediate network node 112, which provides additional connectivity to a plurality of access nodes 140, 140 ', 140 "via network links 141, 141', 141", respectively.

Each access node 140, 140 ', 140 "is depicted providing connectivity to a plurality of N end nodes (144, 146), (144', 146 '), (144", 146 "), respectively, through the corresponding access links (145, 147), (145 ', 147'), (145 ", 147"), respectively. In the exemplary communication system 100, each access node 140, 140 ', 140 "is represented using wireless technology, eg, wireless access links, to provide access. A radio coverage area 148, 148 ', 148 ", eg, a communications cell, of each access node 140, 140', 140", respectively, is illustrated as a circle surrounding the corresponding access node.

The exemplary communication system 100 is subsequently used as the basis for the description of various embodiments of the invention. Alternative embodiments of the invention include various network topologies, in which the number and type of network nodes, the number and type of access nodes, the number and type of end nodes, the number and type of servers, and other agents, the number and type of links, and the interconnectivity between the nodes may differ from those of the exemplary communication system 100 depicted in FIG. 1.

In various embodiments of the present invention some of the functional entities depicted in Figure 1 may be omitted or combined. The location or placement of these functional entities in the network can also be varied.

Figure 2 provides a detailed illustration of an exemplary end node 200, eg, a wireless terminal such as a mobile node, implemented in accordance with the present invention. The exemplary end node 200, depicted in FIG. 2, is a detailed representation of an apparatus that may be used as any one of the end nodes 144, 146, 144 ', 146', 144 ", 146" depicted in FIG. 1 . In the embodiment of Figure 2, the end node 200 includes a processor 204, a wireless communication interface 230, a user input / output interface 240, and a memory 210 coupled to each other via a bus 206. Accordingly, to Through the bus 206 the various components of the end node 200 can exchange information, signals and data. Components 204, 206, 210, 230, 240 of end node 200 are located within a housing 202.

The wireless communication interface 230 provides a mechanism by which the internal components of the end node 200 can send and receive signals to / from external devices and network nodes, eg, access nodes. The wireless communication interface 230 includes, for example, a receiver module 232 with a corresponding receive antenna 236 and a transmitter module 234 with a corresponding transmit antenna 238 used to couple the end node 200 to other network nodes, for example , through wireless communication channels. In some embodiments, the transmitter module 234 includes an orthogonal frequency division multiplexing (OFDM) transmitter.

The exemplary end node 200 also includes a user input device 242, eg, a keypad, and a user output device 244, eg, a display, that are coupled to bus 206 via interface 240. user input / output. Thus, user input / output devices 242, 244 can exchange information, signals, and data with other components of end node 200 through user input / output interface 240 and bus 206. User input / output and associated devices 242, 244 provide a mechanism by which a user can operate the end node 200 to perform various tasks. In particular, user input device 242 and user exit device 244 provide functionality that allows a user to control endpoint 200 and applications, for example, modules, programs, routines, and / or functions, that are they execute in memory 210 of end node 200.

Processor 204 under the control of various modules, eg routines, included in memory 210 controls the operation of end node 200

ES 2 346 696 T3 to perform various signaling and processing as discussed below. Modules included in memory 210 are executed at startup or when called by other modules. Modules can exchange data, information, and signals when they run. Modules can also share data and information when they run. In the embodiment of Figure 2, the memory 210 of the end node 200 of the present invention includes a signaling / control module 212 and signaling / control data 214.

The signaling / control module 212 controls processing related to receiving and sending signals, eg, messages, for managing the storage, retrieval, and processing of status information. The signaling / control data 214 includes status information, eg, parameters, status, and / or other information related to the operation of the end node. In particular, the signaling / control data 214 includes configuration information 216, for example, endpoint identification information, and operational information 218, for example, information about the current processing status, the status of pending responses, etc. . Module 212 accesses and / or modifies data 214, for example, updating configuration information 216 and / or operational information 218.

The message generation module 251 is responsible for generating messages for various operations of the end node 200. Neighbor notification message 280 and signaling message 281 are exemplary messages generated in accordance with the present invention.

The link selection module 213 is responsible for selecting a link, eg, the best link, from the plurality of links available to the end node 200 for transmission of the next message ready for transmission by the end node 200. The link selection algorithm is based on various link quality parameters including at least some of, but not limited to, link transmission power requirements, link error rate, link channel conditions, and link latency. .

The physical layer junction point identifier (PID) determining module 270 is responsible for determining the PID corresponding to broadcast signals received from an access node. The PID determination module 270 includes a cell identification module 271, a carrier identification module 272, and a sector identification module 273. In some, but not all embodiments, a combination of a cell identifier, a carrier identifier, and a sector identifier are used as physical attachment point identifiers. Each of these identifier elements corresponds to physical layer identification information. For example, the cell identifier identifies a physical cell or type of cell. The carrier identifier identifies the physical carrier, eg carrier frequency or tone block while the sector identifier identifies a sector in a corresponding cell. It is not necessary to use all of this information to implement a PID and the particular element of a PID may vary depending on the system implementation. For example, in a system that does not use sectioned cells there would be no need for a 1D sector. Similarly, in a single carrier system there may not be a need for an ID carrier. Performing a PID determination, in an exemplary system, includes the steps of operating cell identification module 271 for determining a cell identifier, operating carrier identification module 272 for determining a carrier identifier and operating the sector identification module 273 for determining a sector identifier. Therefore, it should be appreciated that the different signals passing through a single physical transmitter element, for example, an antenna, may correspond to different physical layer junction points, for example, where each of the different points of Physical layer junctions can be uniquely identified at least within a local area, by a combination of physical identifiers. For example, it should be appreciated that a combination of an antenna or sector identifier can be used in combination with a first carrier identifier to identify a first physical layer junction point while a second carrier identifier can be used in combination with the same antenna. or sector identifier to identify a second physical layer junction point.

The physical layer junction point identifier (PID) information 260 is a list of PIDs (PID1 261, PID2 262), which are PIDs determined using the PID determination module 260. An exemplary implementation of a physical layer junction point identifier (PID) may be a connection identifier (CID) that can be included in messages when messages are sent and / or received. Particular exemplary CIDs are discussed further below.

Memory 210 also includes a neighbor notification module 290, a message transmission control module 292, and a link establishment module 294. The neighbor notification module 290 is used to transmit a neighbor notification, eg, a neighbor notification message 280, to the access nodes. The message transmission control module 292 is used to control the transmitter module 234. The link establishment module 294 is used to establish wireless communication links with access nodes.

Figure 3 provides a detailed illustration of an exemplary access node 300 implemented in accordance with the present invention. The exemplary access node 300, depicted in FIG. 3, is a detailed representation of an apparatus that may be used as any one of the access nodes 140, 140 ', 140 "depicted in FIG. 1. In the embodiment of Figure 3, the access node 300 includes a processor 304, a memory 310, a network / inter-network interface 320, and a wireless communication interface 330, coupled together via a bus 306. Accordingly, a Through the bus 306 the various components of the access node 300 can exchange information, signals and data. Components 304, 306, 310, 320, 330 of access node 300 are located within a housing 302.

The network / inter-network interface 320 provides a mechanism by which the internal components of the access node 300 can send and receive

ES 2 346 696 T3 signals to / from external devices and network nodes. The network / inter-network interface 320 includes a receiver module 322 and a transmitter module 324 used to couple node 300 to other network nodes, for example, via copper wires or fiber optic lines. The wireless communication interface 330 also provides a mechanism by which the internal components of the access node 300 can send and receive signals to / from external devices and network nodes, eg, end nodes. The wireless communication interface 330 includes, for example, a receiver module 332 with a corresponding receive antenna 336 and a transmitter module 334 with a corresponding transmit antenna 338. Interface 330 is used to couple access node 300 to other network nodes, for example, through wireless communication channels.

Processor 304 under the control of various modules, eg, routines, included in memory 310 controls the operation of access node 300 to perform various signaling and processing. Modules included in memory 310 are executed at startup or when called by other modules that may be present in memory 310. The modules can exchange data, information, and signals when they are executed. Modules can also share data and information when they run.

In the embodiment of Figure 3, the memory 310 of the access node 300 of the present invention includes a signal generation module 314 for generating signals, a packet routing module 350 responsible for routing signals and messages, a mapping module 312 that is responsible for mapping PIDs to network layer addresses, an address resolution table 311 that includes mappings 317 of PIDs to IP address. Memory 310 also includes an endpoint identification module 351 that identifies endpoints with which access node 300 is in communication, uplink resource allocation information 340 responsible for allocating uplink resources to network nodes. end, including resources assigned to an end node X 341, and downlink resource allocation information 345 responsible for allocating downlink resources to end nodes, including resources allocated to an end node X 346.

Referring now briefly to Figure 9, Figure 9 illustrates an address resolution table 311 'that can be used as the address resolution table 311 shown in Figure 3. The address resolution table 311' includes PID 902, 904, 906, 908, 910, 912 and information indicating the corresponding IP addresses 903, 905, 907, 909, 911, and 913, respectively. The PIDs are each locally unique, for example, the PIDs of immediately adjacent cells are unique with respect to each other. Note that the content of the PIDs may vary depending on the physical characteristics of the access node and the number of physical layer junction points supported by the access node to which the PID corresponds. In the example of figure 9, the PIDs 902, 904 correspond to a first access node (AN 1) that supports two sectors using the same carrier. Therefore, in the case of AN 1, it is sufficient that the PID includes a cell identifier and a sector type identifier to uniquely identify the physical layer junction points in the cell. PIDs 906, 908, 910 correspond to a cell that supports multiple carriers and multiple sectors. Accordingly, the PIDs for access node '2 are implemented as CIDs in the same manner as used in various exemplary embodiments discussed further herein. PID 912 corresponds to a third access node that includes a single sector and uses a single carrier. Therefore, it is sufficient that the PID 6 corresponding to the third access node includes only a cell identifier despite an additional physical layer identification, eg a sector and / or carrier identifier. The inclusion of such additional information may be desirable when, from a processing perspective, consistent PID formats across multiple cells are desirable.

Referring now to Figure 4, Figure 4 illustrates an exemplary connection identifier (CID) 400 implemented in accordance with the present invention. The CID 400 includes a slope 410, which is a cell identifier, a sector 420 which is a sector identifier, and a carrier 430, which is a carrier frequency identifier also known as a tone block identifier.

In an exemplary communication system using OFDM technology, at the physical layer, the spectrum is divided into a series of tones and reused in cells and sectors in neighboring geographic areas. In order to improve the interference characteristics, the tones used in each cell / sector jump over time, and different cells and sectors in neighboring geographic areas use different jump sequences, which specify how the tones should jump. Jump sequences are generated using a predetermined function controlled with two input variables, namely, the cell identifier, eg, a slope value, and a sector identifier. The sector identifier may be implemented as a sector type identifier indicating to which of a plurality of possible sector types a particular sector corresponds. In one embodiment, the slope value is an integer from 1 to 112, and the sector identifier value is an integer from 0 to 5. Neighboring sectors and cells use different pairs of slope and sector identifier so that the generated jump sequences are different. In one embodiment, all sectors in a cell use the same slope value but different sector identifiers, and neighboring cells, for example physically adjacent, use different slope values.

Furthermore, the exemplary OFDM communication system, in some embodiments, uses multiple carriers or blocks of tones, so that the available tones are grouped into multiple blocks of tones. The tones in a tone block are preferably contiguous. In an exemplary system, the pitch hopping in a given tone block is limited to that tone block. That is, the jump sequences are such that tones can jump within the tone block but cannot jump through multiple tone blocks. Tone blocks are indicated by a carrier identifier. In one embodiment, the carrier identifier is an integer 0, 1, or 2.

When an end node establishes a connection to obtain networking services ina

ES 2 346 696 T3, the entity on the network side is an access node, eg a base station in a cell / sector, and the connection is defined with respect to a single block of tones. Thus, in the above exemplary OFDM communication system, a combination of pending, sector identifier, and bearer identifier may be used as a locally unique identifier that identifies the connection for the wireless terminal. The combination is therefore a connection identifier based on one or more physical layer identifiers. In one embodiment, multiple wireless terminals may have connections to the same base station cell / sector on the same tone block. Those connections will typically share the same connection identifier since they are connected to the same physical layer junction point as defined by the combination of cell, sector, and tone block. The combination of the connection identifier and a wireless terminal identifier can be used to indicate a communication connection with a particular wireless terminal.

In general, the connection identifier is a number or combination of numbers that uniquely identifies a connection locally. In various embodiments, the number or numbers are characteristic physical layer parameters. In another embodiment, for example, an exemplary embodiment of a CDMA communication system, the connection identifier may be the combination of a pseudo-noise (PN) sequence offset and another parameter, for example, a carrier identifier if multiple carriers.

Figure 5 illustrates an exemplary message 500, in accordance with the present invention, using the connection identifier of Figure 4: the exemplary message 500 is a link layer message that includes a source / destination address CID. The source / destination address CID is an optional field in link layer messages according to some embodiments of the present invention. The link layer message 500 includes a link layer control (LLC) type field 510 that identifies the message body type 530 included in the message 500. The CID 520 is a connection ID in the form of the ID 400 connection of figure 4. In one embodiment of the present invention the CID field 520 identifies a destination physical junction point when sent from an end node to an access node according to the invention and identifies a source physical junction when sent from an end node. access to an end node according to the invention.

Figure 6 illustrates an exemplary communication procedure and corresponding signaling performed according to a first design. In Figure 6 end node 630 communicates with access node 620 through access node 610 without a wireless uplink between end node 630 and access node 620 and without the end node having to know an IP address of the access node 620. The signaling is illustrated in the context of the exemplary system 100 illustrated in Figure 1. The access nodes 610 and 620 are similar to the access nodes 140, 140 'and 140 "of the system 100 in Figure 1 and are implemented according to the access node 300 of FIG. 3. End node 630 is similar to end node 144, 146, 144 ', 146', 144 ", and 146" of system 100 in FIG. 1, and is implemented according to node 200 end in figure 2.

In FIG. 6, end node 630 maintains a bi-directional link with access node 610, which means that it can send messages to and receive messages from access node 610. The end node 630 in FIG. 6, although within transmission range of the access node 620, does not have an uplink to the access node 620. This means that although the end node 630 can receive and process broadcast information sent by the access node 620 (for example, broadcast messages 640), the end node 630 cannot send messages to the access node 620 over the air. and the access node 620 cannot receive and process messages sent thereto by the end node 630 over the air interface. This may be because end node 630 and access node 620 do not have sufficient time synchronization. Due to certain limitations, for example limited hardware capacity, the end node 630 may not be able to establish an uplink connection to the access node 620 while the end node 630 currently has a bi-directional connection to the access node. access node 610. In one design, the uplinks used by the access node 610 and the access node 620 are on different carriers, for example, the frequency band of the uplink used by the access node 610 is different from the frequency band of the uplink used by access node 620. If the end node 630 can generate only one uplink signal in a band at a given time, for example, because the end node 630 only has one radio frequency (RF) chain due to cost considerations, then the node 630 Endpoint cannot simultaneously maintain two uplink connections on two separate frequency bands. In another design where the uplinks used by access nodes 610 and 620 are in the same band, it may be that the two uplinks are not time synchronized, because the two access nodes are not time synchronized. or due to the difference in propagation delay for the signal to reach the access nodes 610 and 620 from the end node 630. If the end node 630 can generate only one uplink signal according to a time synchronization scheme at a time, for example, because the end node 630 has a single digital processing chain limited to one time scheme at a time, then the end node 630 cannot simultaneously maintain two uplink connections, when the connections are not sufficiently time synchronized with each other.

End node 630 receives (a) broadcast signal (s) 640 that are transmitted by access node 620. The signal (s) 640 are sufficient to determine the connection ID, similar to the CID 400 of FIG. 4, corresponding to the specific physical junction of the access node 620 that transmits the broadcast signal 640. The signals or signals 640 may include beacon and / or pilot signals that may be transmitted for one or more symbol transmission time periods.

The end node 630 transmits a message 650 to the access node 610. In an exemplary design, said message 650 is the same as, or similar to, the exemplary message 500 of Figure 5. The CID field, equivalent to CID 520 of Figure 5, of said message 650 is set to the connection identifier that identifies the physical junction point of the access node 620 you gave

ES 2 346 696 T3 fused the signal 640. Said message 650 is therefore intended for the access node 620 although it is sent to the access node 610. Note that since end node 630, in the example of FIG. 6, does not have an uplink to access node 620, it cannot send message 650 directly to access node 620.

The access node 610 receives the message 650 and examines the CID field, corresponding to the CID 520 of Figure 5, of the message 650 and realizes, by the stored CID, the link layer identification information that it does not identify. one of its own physical attachment points. In such a case, access node 610 searches its memory for said CID of message 650 to find a correlation with a corresponding higher layer identifier for access node 620 (eg, an IP address).

For example, a base station that includes multiple sectors operating under a single link layer controller and / or multiple carriers used under a single link layer controller may have multiple CIDs corresponding to a link layer identifier corresponding to a single link layer controller. In designs where separate link layer controllers are used for each sector and / or carrier, different link layer identifiers can be used for each of the different sectors and / or carriers. In some designs, there is a one-to-one correlation between physical tie points and tie layers but it is not required and there may be multiple physical tie points operating under a single tie layer. Thus, multiple physical layer identifiers may correspond to the same link layer link identifier although each physical layer identifier connection identifier is normally mapped to at most a single link layer link identifier.

Assuming a correlation to a higher layer address is found, the access node 610 encapsulates at least part of the 65C message in a network layer message 660 that includes a destination address matched to the access node 620 identifier and transmits said message 660 to access node 620. According to this design the message 660 also includes an end node identifier 630, said identifier being, depending on the design, one of an end node 630 IP address, an end node 630 network access identifier (NAI) and a temporary identifier. The access node 620 receives said message 660 and extracts the encapsulated part of the message 650 from it. Access node 620 inspects the CID field of the encapsulated portion extracted from message 650 and recognizes that the CID field identifies one of its physical junction points.

Access node 620 sends message 670 which includes at least part of received message 650 encapsulated in message 660 by access node 620. Said message 670 also includes an end node identifier 630 similar to that included in message 660. Access node 610 then receives message 670 and examining the included end node identifier determines that message 670 encapsulates a message 680 intended for the end node 630. The access node 610 then sends the message 680 which includes at least part of the message

670. According to the present invention the message 680 includes the CID of the physical junction point of the access node 620 that broadcasts the signal 640.

End node 630 receives message 680 from access node 610 but examining the CID field included in said message 680, for example, comparing it with stored CID information, determines that message 680 originates from node 620 from access in response to message 650 previously sent thereto.

Figure 7 illustrates exemplary signage made according to a second design. The signaling is illustrated in the context of the exemplary system 100 illustrated in Figure 1. End node 710 is a simplified representation of end node 200 of Figure 2 and is the same as, or similar to, nodes 144, 146 , 144 ', 146', 144 ", 146" end of system 100 in Figure 1. Access nodes 740 and 750 are similar to access nodes 140, 140 ', and 140 "of system 100 in Figure 1 and are implemented using access node 300 of Figure 3. In Figure 7, node 710 The endpoint includes a message generation module 720 and a link selection module 730. The message generation module 720 of FIG. 7 can be used by applications running at the end node 710 to generate messages for their purposes. For example a connection control protocol application may be included and active at end node 710 allowing end node 710 to communicate with access nodes for the purposes of creating, disconnecting and / or modifying links between node 710. endpoint and one or both access nodes 740, 750. Another example is a quality of service (QoS) application that can be included in the end node 710. The application of QOS when present can modify QoS characteristics of the various links of the end node 710. The link selection module 730 of Figure 7 measures various metrics for connection quality including requirements for link transmission power, link error rate, link channel conditions, and link latency to determine, for example, message per message or at a particular point in time, which of the available links is the most appropriate for the transmission of the next message.

The resulting link quality information can be used, and in various designs is used, to determine to which of the plurality of simultaneous links a message should be transmitted at a particular point in time.

In Figure 7, end node 710 maintains bi-directional links with access nodes 740 and 750, which means that it can send messages to and receive messages from access nodes 740 and 750. In this design the message generation module 720 of the end node 710 generates the message 759 with the final destination access node 740. Message 759 is sent first to link selection module 730 of end node 710. Link selection module 730 selects the link between links to access nodes 740 and 750 over which the next message is to be transmitted. The link determination function is based on link characteristics including at least one of link transmission power requirements, link error rate, link channel conditions, and link latency.

ES 2 346 696 T3

In the design depicted in FIG. 7, the link selection module 730 selects the link to the access node 740 and transmits the message 760 over it. Message 760 includes at least some portion of message 759 and, in some designs, includes additional fields used for transmission of a message over the link between end node 710 and access node 740. For example, the additional fields are, in some layouts, link frame fields. Since the final destination of messages 759 and 760 is access node 740, access node 740 receives message 760, processes the received message, and responds, for example, by transmitting message 765 to end node 710. The message 765 is received by the end node 710 and delivered to the message generation module as message 766. The message generation module 720 generates a second message 769 with the access node 740 being the final destination. Message 769 is sent to link selection module 730 which selects the link on which message 769 is to be transmitted. In this design the link to access node 750 is selected and message 770 is transmitted to access node 750. Message 770 includes at least a portion of message 769 and in some design includes additional fields used for transmission of the message over the link between end nodes 710 and 750. For example, the additional fields are, in some embodiments, link frame fields.

In one design the link selection module 730 adds an identifier, for example, a physical attachment point identifier, of the access node 740 along with at least a portion of the message 769 that comprises the message 770, because the link selected by the link selection module 730 for the transmission of the message 770 does not correspond to the final destination of the message 770, which is the access node 740. In another design the link selection module adds the identifier of the final destination of messages 760 and 770 before it transmits said messages 760 and 770, regardless of which link is selected for transmission. In a further design, messages 759, 769 include the identifier of their final destination. For example in an example of the exemplary design of FIG. 7 the identifier of the final destination corresponds to the access node 740.

In an exemplary design, message 770 is implemented in accordance with message 500 of FIG. 5, in which CID field 520 identifies access node 740. Access node 750 receives message 770 and processes it. By examining the final destination of message 770, for example, a physical attachment point identifier in CID field 520 of message 500 of Figure 5, access node 750 determines that message 770 is not intended for this but for some another node identified by the final destination identifiers (for example, a CID in the CID field). Access node 750 queries the physical junction point identifier (PID) included in message 770 in its address resolution table (see address resolution table 311 in access node 300 of Figure 3) to find the network address (for example, the IP address) corresponding to the PID included in the 770 message.

Access node 750 encapsulates at least a portion of message 770 in an appropriate network layer header and transmits message 775 to access node 740. Message 775 includes at least: a portion of message 770, and at least some of the IP address of the access node 740. In addition, message 775 includes in various designs some or all of the following: the IP address of the access node 750, the PID of the access node 740 included in the message 770, the PID of the access node 750 through which the message 770, end node identifier 710, and session identifiers for encapsulation (also called tunneling) of messages between access node 750 and access node 740. The access node 740 receives the message 775 which it recognizes as the intended message for it from the destination PID included in the message 775.

In one design the access node 740 responds by transmitting the message 780 that includes at least part of the message 775. The access node 750 receives the message 780, which includes the end node identifier 710 and sends the message 785 to the node 710 of extreme. Message 785 includes at least part of message 780. End node 710 receives message 785 and forwards message 786 to message generation module 720.

In another design the access node 740 responds by transmitting, to the end node 710, the message 780 'which includes at least part of the message 775. The message 780' is transmitted over the direct link between the access node 740 and the node 710 extreme.

Figure 8 illustrates exemplary signaling performed in accordance with exemplary embodiments of the invention in which an end node is used as part of a neighbor discovery and CID routing information update process. The signaling is illustrated in the context of an exemplary system such as the system 100 illustrated in Figure 1. End node 810 is a simplified representation of end node 200 of FIG. 2 and is the same as or similar to end nodes 144, 146, 144 ', 146', 144 ", 146" of system 100 in FIG. 1. Access nodes 840 and 850 are the same or similar to access nodes 140, 140 'and 140 "of system 100 in Figure 1 and can be implemented, for example, using access nodes of the type illustrated in Figure 3 . In the example of FIG. 8 the end node 810 has a two-way communication link with the access node 840, which allows it to send messages to and receive messages from the access node 840.

In FIG. 8, end node 810 generates and transmits message 860 to access node 840. Message 860 includes an identifier that identifies access node 850 as the destination of that message. Access node 840 receives message 860 and attempts to resolve access node identifier 850 included in that message to a network address by looking up its address resolution table, for example, node address resolution table 311. 300 of figure 3. In the example of figure 8 the access node 840 does not resolve said identifier. Access node 840 then transmits message 865 to end node 810. Message 865 includes an indication that a message routing was not possible due to a resolution failure.

In one embodiment of the present invention the end node 810 establishes at this point a two-way communications link with the access node 850 by exchanging a variety of messages displayed as a double arrow message 870 on the

ES 2 346 696 T3 Figure 8. However, this is not necessary if a bidirectional link already exists with the access node 850. In another example using the invention, end node 810 already has a bi-directional link to access node 850 in addition to the link to access node 840.

Using the link to the access node 850, the end node 810 transmits a new neighbor notification message 875 to the access node 850. The message 875 includes at least one access node identifier 840 and the network layer address of the access node 840. Thus, the access node 850 is supplied with both an identifier, for example the PID of the access node 840, and a corresponding link layer address, for example, the MAC address that the access node 850 can address and store. for future resolution of a physical layer to the network layer identifier. In one embodiment of the present invention the access node identifier 840 is a physical attachment point identifier; in another embodiment of the present invention it is a link layer identifier. The network layer identifier of the access node 840 is known to the end node 810 from communication messages 897 communicated to the end node 810 during or after the establishment of the link with the access node 840.

In an alternative embodiment of the present invention end node 810 sends message 875 'instead of message 875. Message 875' has the same or similar message content as message 875 but is sent to access node 850 via of the access node 840, instead of the access node 850 directly. Access node 840 then routes message 875 'as message 875 "to access node 850. Note that unlike message 860, message 875 'is a network layer message that includes the access node 850 network address as its destination. The network address of the access node 850 is known to the end node 810 from communication messages 899 communicated during or after the establishment of the link with the access node 850. For this reason, the access node 840 can route the message 875 "to the access node 850 using a network address of the access node 850, for example the IP address, without having to perform a CID resolution operation against the address.

Access node 850 receives message 875 and sends a new neighbor creation message 880 to the network address of access node 840, retrieved from message 875. Message 880 includes a connection identifier for address layer mappings. network for access node 850. In another embodiment of the present invention, message 880 includes link layer identifiers for network layer address mappings for access node 850. In another embodiment of the present invention the message 880 includes additional neighbor information used to host end node handovers, including but not limited to tunnel session identifiers and tunnel address to redirect packets between access nodes 840 and 850, capabilities of the access node 850 with respect to quality of service, load, protocols and supported applications. The access node 840 receives the message 880 and stores the information included in the message 880 in its memory, for example, for future use in resolving operations of CID with respect to network address. The access node 840 responds with a message 882 acknowledging the receipt of said information included in the message 880.

In one embodiment of the present invention the access node 840 includes in the message 882 some mapping of connection identifier to network layer address for the access node 850, mappings of link layer identifiers to network layer address for access node 850, neighbor information used to host end node handovers, including but not limited to tunnel session identifiers and tunnel address to redirect packets between access nodes 840 and 850, and or information indicating capabilities of the access node 840 with respect to quality of service, load, protocols, and supported applications . Access node 840 receives message 880 and stores the information included in message 880 in its memory, or for example, for future use in routing messages. In this particular embodiment of the invention the messages 883 and 884 are not used.

In another embodiment of the present invention, the message 882 from the access node 840 includes an acknowledgment of receipt of the information included in the message 880. In this embodiment of the invention the access node 840 sends the message 883 including at least some correlations of connection identifier to network layer address for the access node 850, correlations of link layer identifiers with network layer address network for access node 850, neighbor information used to host end node handovers, including but not limited to tunnel session identifiers and tunnel address for redirecting packets between access nodes 840 and 850, capabilities of access node 840 with respect to quality of service, load, protocols, and supported applications. Access node 850 receives message 883 and stores the information included in message 883 in its memory, for example, for future use. Access node 850 responds with message 884 acknowledging receipt of said information.

Following exchanges of neighbor information and identifier-to-address mappings between access nodes 840 and 850 through messages 880, 882 and optionally 883 and 884, end node 810 sends message 890 to access node 840. Like message 860, in one embodiment of the invention message 890 is also the same or similar to message 500 of Figure 5. Message 890 identifies access node 850 as its final destination. Access node 840, receives message 890, searches its memory for a correlation between access node identifier 850 and a network address for said node 850, and finds said network address in its address resolution table that was previously occupied by message 880. Access node 840 encapsulates message 890 based on the information in the resolution table and sends it to access node 850 as message 891. Access node 850 responds with message 892 again using the information in its address resolution table and message 891. Access node 840 sends message 893 to end node 810 including at least part of message 892 received from the access node 850 completing the communication exchange

ES 2 346 696 T3 between end node 810 and access node 850 through access node 840.

In the manner described above, through the use of messages from end node 810, access nodes 840 and 850 are provided with PID and / or address information about each other that can be used in routing subsequently received messages. Consequently, as access nodes are added to the network, the end nodes can serve to discover their presence from broadcast signals and notify the access nodes of new neighbors. Sufficient address information is distributed as part of the notification process to facilitate network PID-based routing of messages after the notification process has been completed.

In various embodiments the nodes described herein are implemented using one or more modules to perform the steps corresponding to one or more methods of the present invention, eg, signal processing, message generation, and / or transmission steps. Thus, in some embodiments, various features of the present invention are implemented using modules. Such modules can be implemented using software, hardware, or a combination of software and hardware. Many of the procedures or procedural steps described above can be implemented using machine-executable instructions, such as software, included on a machine-readable medium such as a memory device, eg, RAM, a floppy disk, etc. to control a machine, for example a general purpose computer with or without additional hardware, to implement all or parts of the procedures described above, for example, on one or more nodes. Accordingly, among other things, the present invention relates to a machine-readable medium that includes machine-executable instructions for causing a machine, for example, a processor and associated hardware, to perform one or more of the steps of the (of the) procedure (s) described above.

Numerous additional variations of the methods and apparatus of the present invention described above will be apparent to those skilled in the art in light of the foregoing description of the invention. Such variations should be considered within the scope of the invention. The methods and apparatus of the present invention can be used, and in various embodiments are used, with CDMA, orthogonal frequency division multiplexing (OFDM), or various other types of communication techniques that can be used to provide wireless communication links between nodes. access and mobile nodes. In some embodiments the access nodes are implemented as base stations that establish communication links with mobile nodes using OFDM and / or CDMA. In various embodiments the mobile nodes are implemented as laptop computers, personal data assistants (PDAs), or other portable devices including receiver / transmitter circuits and logic and / or routines, to implement the methods of the present invention.