Ad hoc networking of terminals aided by a cellular network

Description of equivalent WO 2004001521 A2

AD HOC NETWORKING OF TERMINALS AIDED BY A CELLULAR

NETWORK

Field of the Invention

The present invention relates to IP networks, and more particularly to establishing ad hoc networking among terminals aided by a cellular network.

Background of the Invention

The development of mobile communication devices and mobile networks has advanced at a rapid rate. At first, analog mobile networks enabled voice communication and simple paging features. Later, digital mobile networks provided more advanced features for voice and data communication, such as encryption, caller identification and short message service (SMS) text messages. More recently, third generation (3G) mobile IP network technology is being developed to enable users to easily access content rich media, information and entertainment with mobile devices.

As networks advance, WLAN cellular networking is becoming an intensely discussed issue. Many see WLAN as an important component in the 3G evolution. For example, 3GPP is currently conducting feasibility studies on WLAN UMTS interworking. The interest is not limited to 3GPP only but has also drawn attention at 3GPP2 and the Mobile Wireless Internet Forum (MWIF). Other evolution paths for interworking between cellular networks and ad hoc capable networks can be seen in e.g. Bluetooth, Infrared and Wireless Routing (WR).

Exchanging data between two mobile terminals may be costly if conducted over the cellular infrastructure or if the terminals are co-located. Using a WLAN, Bluetooth or Infrared, or any other peer-to-peer interface for keeping a high rate (and possibly also volume) traffic local is efficient from a cost, bandwidth and spectrum usage point of view. Current WLAN, infrared (IR) and emerging Bluetooth/IEEE 802.15 (BT) standards would allow for the interface, but it is very difficult and clumsy to achieve a desired trusted security level between the terminals. Typically the connection set-up has would be done manually. Additionally, cellular operator revenue is lost when only using a WLAN/BT/IR/WR, or other non-cellular connection. A problem, however, is that current solutions offer limited functionality

1 M&G No. 50072.19WO0I/NC16582 and usability. Current connection setup is standardized, e.g., for WLAN in IEEE 802.11b.

What is needed is a way to establish secure links using cellular operator-controlled devices and a way for an operator to be involved in local traffic exchange that bypasses the infrastructure and thus offers a tool for additional revenue that would otherwise escape the operator. It is with respect to these considerations and others that the present invention has been made.

Summary of the Invention

The present invention is directed at addressing the above-mentioned shortcomings, disadvantages and problems, and will be understood by reading and studying the following specification.

According to one aspect of the invention, mobile nodes equipped with a non-cellular wireless interface may establish a high data rate peer-to-peer ad hoc connection with the support of a cellular network. The cellular network may provide signaling for user authentication, peer identification, authentication key distribution for a secure non-cellular connection set-up, radio resources management messages, as well as charging and billing for the service. This is especially true, if one of the terminals is a server of music, games, streaming video, and the like.

According to another aspect of the invention, the non-cellular link may be used for fast and secure ad hoc communication between the terminals. Signaling may be carried either over a non-cellular wireless access network or, using dual-mode terminals, over the cellular Radio Access Network (RAN). A combination of the signaling transport media is also possible. For example, one user may carry signaling over a WLAN RAN and the other user may carry signaling over a cellular system. According to yet another aspect of the invention, the cellular system is not limited to the Universal Mobile Telecommunications System (UMTS). Cellular network, as used in this application refers to any mobile network operated by an operator. For example, without limiting to these, the cellular network can be a GSM, GPRS, UMTS, using various radio access network technologies, such as CDMA2000, WCDMA and WLAN. Similarly, the non-cellular network and interface for the ad- hoc link may be any of the family of short range radios including BRAN Hiperlan, Hiperlan2, IEEE 802.1 la,b, g, Multimedia Mobile Access Communication (MMAC) M&G No. 50072.19WO01/NC16582 High-Speed Wireless Access (HISWA), Bluetooth, IEEE 802.15, and the like. The short range connection may even be a wired or infrared connection without departing from the spirit of this invention.

According to a further aspect of the invention, a cellular infrastructure is used to identify and authenticate the mobile users, and deliver one or more encryption keys or tokens for a secure non-cellular link establishment. Number and kind of needed encryption keys or security association tokens is dependent on the security method(s) employed in the network, which is not a part of this invention. Any kind of suitable security method(s) can be employed in accordance to this invention. This eases the process and possibly generates additional revenue for an operator. For instance, the authentication and encryption (security) signaling services provided by the cellular network could be charged for. Another example for chargeable services can be routing assistance based on a dynamically updated register in the cellular network, which creates a description of the ad hoc network and provides optimized routing information for mobile nodes based on that description. Yet another example of such chargeable services is QoS (quality of service) support provided by the cellular infrastructure and supervised by the operator. In addition, if one of the terminals offers commercial services, this arrangement allows reusing the cellular billing infrastructure for charging for the service. According to still yet another aspect of the invention, a terminal is provided, which is able to communicate over ad hoc communication links with assistance provided from the cellular network for establishing the communication. The terminal receives information optimized for the terminal from the cellular network used in establishing communication links. According to a further aspect of the invention, a network node associated with cellular network for providing services associated with an ad hoc network can form descriptions of an ad hoc network for terminals associated with an ad hoc network. The network node receives requests for assistance from terminals for assistance in establishing a communication link. In response to the request, the network node provides an optimized answer to the terminal. The optimized answer may provide information relating to routing, quality enhancement, and security and authentication. According to one embodiment of the invention, the network node provides server or register functionality.

3 M&G No. 50072.19WO01/NCI6582 Brief Description of the Drawings

FIGURE 1 illustrates an exemplary cellular network in which the invention may operate;

FIGURE 2 shows a schematic diagram that illustrates an exemplary system overview in which local area networks and a wide area network are interconnected by routers;

FIGURE 3 shows exemplary ad hoc networking of terminals over a Non-Cellular interface aided by a cellular network;

FIGURE 4 shows exemplary ad hoc network in which some of the terminals employ a non-direct connection (i.e. a multi-hop connection) to the cellular network;

FIGURE 5 illustrates an operator controlled central register system; and

FIGURE 6 illustrates a process for ad hoc networking of terminals over a Non-cellular interface aided by a cellular network, in accordance with aspects of the invention.

Detailed Description of the Preferred Embodiment

In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanied drawings, which form a part hereof, and which is shown by way of illustration, specific exemplary embodiments of which the invention may be practiced. Each embodiment is described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.

Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The term "node" refers to a node on a network. The term "mobile node" and "terminal" refer to a node on the network that is mobile. The term "flow" means a flow of packets. The term "support node" refers to both "GGSN" and "SGSN" nodes. The term "user" refers to any person or customer such as a business or organization

A M&G No 50072 19WO01/NC16582 that employs a mobile device to communicate or access resources over a mobile network. The term "operator" refers to any technician or organization that maintains or services something, such as a network. The term "identifier" refers to a user address, an IMSI code, an MSISDN number, an IP address, or any other information that relates to the location or identity of the user or equipment.

In an exemplary implementation described in this application, AAA (Authentication, Authorization and Accounting) device is referred. AAA is an IETF standard developed by the Authentication, Authorization and Accounting (AAA) Working Group. The work of this group is ongoing, and a reference is made to the proceedings of this working group, both existing and forthcoming, (http://www.ietf.org/html.charters/aaa-charter.html) in its entirety. Instead of AAA, any other existing or future system and method can be employed for authentication, authorization and accounting without departing from the spirit of this invention.

The term "AAA device" refers to any device that offers the functionality of an AAA server generally associated with an IP network. Other nodes or systems of cellular networks may offer the AAA functionality. There include, but are not limited too, entities as charging centers, gateways, resource management entities, user profiles stored in location registers etc Referring to the drawings, like numbers indicate like parts throughout the views. Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or is inconsistent with the disclosure herein.

Illustrative Operating Environment

With reference to FIGURE 1, an exemplary cellular network coupled with data networks, in which the invention may operate is illustrated. As shown in the figure, network 100 includes mobile node (MN) 105, radio access network (RAN)

110, SGSN 115, core network 120, routers 125_D-_F, optional authentication, authorization, and accounting (AAA) server 300, GGSNs 135_A-_B, data network 140, and data network 145.

The connections and operation for network 100 will now be described. MN 105 is coupled to radio access network (RAN) 110. Generally, MN 105 may include any device capable of connecting to a wireless network such as radio access network 110. Such devices include cellular telephones, smart phones, pagers, radio

5 M&G No. 50072.I9WO0I/NCI6582 frequency (RF) devices, infrared (IR) devices, integrated devices combining one or more of the preceding devices, and the like. MN 105 may also include other devices that have a wireless interface such as Personal Digital Assistants (PDAs), handheld computers, personal computers, multiprocessor systems, microprocessor-based or programmable consumer electronics, network PCs, wearable computers, and the like. Radio Access Network (RAN) 110 manages the radio resources and provides the user with a mechanism to access core network 120. Radio access network 110 transports information to and from devices capable of wireless communication, such as MN 105. Radio access network 110 may include both wireless and wired components. For example, radio access network 110 may include a cellular tower that is linked to a wired network. Typically, the cellular tower carries communication to and from cell phones, pagers, and other wireless devices, and the wired network carries communication to regular phones, long-distance communication links, and the like. Some nodes may be General Packet Radio Service (GPRS) nodes. For example, Serving GPRS Support Node (SGSN) 115 may send and receive data from mobile nodes, such as MN 105, over RAN 110. SGSN 115 also maintains location information relating to MN 105. SGSN 115 communicates between MN 105 and Gateway GPRS Support Node (GGSN)s 135_A-_B through core network 120. According to one embodiment of the invention, AAA device 300 communicates with core network 120.

Core network 120 may be an IP packet based backbone network that includes routers, such as routers 125_D-F, to connect the support nodes in the network. Routers are intermediary devices on a communications network that expedite message delivery. On a single network linking many computers through a mesh of possible connections, a router receives transmitted messages and forwards them to their correct destinations over available routes. Routers may be a simple computing device or a complex computing device. For example, a router may be a computer including memory, processors, and network interface units. GGSNs 135_A-B are coupled to core network 120 through routers 125_A-c and act as wireless gateways to data networks, such as network 140 and network 145. Networks 140 and 145 may be the public Internet or a private data network. GGSNs 135_A-B allow MN 105 to access network 140 and network 145. g M&G No. 50072.19WO01/NC16582 Briefly described, AAA device 300 may be used to monitor and aid in carrying out the operator's control for the communication through ad hoc networks. AAA device 300 may be coupled core network 120 through communication mediums. AAA device 300 may be programmed by an operator with instructions to manage the policies relating to mobile network 100. AAA device 300 is an optional element.

The operator may set threshold levels to determine whether or not to accept a new flow based on different service classes for a particular user or group of users. The routers, or a dedicated network element, such as AAA device 300, may be used for this purpose. Utilizing an AAA device helps to enforce authentication, authorization, and accounting rules to help ensure end-to-end quality of service (QoS) for users. Operators have the flexibility to provide different AAA rules. For example, conversational traffic may be mapped into either the Expedited Forwarding (EF) class or Assured Forwarding (AF) class at the core network. The operator may employ a different charging structure for each class. Also, AAA rules may be established nodes using different signaling transports.

Furthermore, computers, and other related electronic devices may be connected to network 140 and network 145. The public Internet itself may be formed from a vast number of such interconnected networks, computers, and routers. Mobile network 100 may include many more components than those shown in FIGURE 1. However, the components shown are sufficient to disclose an illustrative embodiment for practicing the present invention.

The media used to transmit information in the communication links as described above illustrate one type of computer-readable media, namely communication media. Generally, computer-readable media includes any media that can be accessed by a computing device. Communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term "modulated data signal" means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, communication media includes wired media such as twisted pair, coaxial cable, fiber optics, wave guides, and other

7 M&G NO. 50072.19WO01/NC16582 wired media and wireless media such as acoustic, RF, infrared, and other wireless media.

FIGURE 2 shows another exemplary system in which the invention operates in which a number of local area networks ("LANs") 220_a- , wireless local area networks 250_A-c,and wide area network ("WAN") 230 interconnected by routers 210. Optionally, AAA device 300 may be coupled to various places within the system to provide AAA services.On an interconnected set of LANs and WLANs— including those based on differing architectures and protocols--, a router acts as a link between LANs, enabling messages to be sent from one to another. Communication links within LANs typically include twisted wire pair, fiber optics, or coaxial cable, wherein communication links within WLANs include wireless links, while communication links between networks may utilize analog telephone lines, full or fractional dedicated digital lines including TI, T2, T3, and T4, Integrated Services Digital Networks (ISDNs), Digital Subscriber Lines (DSLs), wireless links, or other communications links. Furthermore, computers, such as remote computer 240, and other related electronic devices can be remotely connected to either LANs 220_a-d or WAN 230 via a modem and temporary telephone link. The number of WANs, LANs, and routers in FIGURE 2 may be increased or decreased without departing from the spirit or scope of this invention. As such, the Internet itself may be formed from a vast number of such interconnected networks, computers, and routers and that an embodiment of the invention could be practiced over the Internet without departing from the spirit and scope of the invention. It should be noted that instead of a WLAN (as defined in IEEE 802.11 standards), the WLAN in this example may represent any kind of a wireless local area network, i.e. such as Bluetooth wireless network.

AAA device 300 may include program code that maintains the rules to charge and authorize the user for the ad hoc non-cellular connections set-up between terminals.

Ad Hoc Networking of Terminals over Non-Cellular Interface Aided by a Cellular Network

FIGURE 3 shows exemplary ad hoc networking of terminals over a Non-Cellular interface aided by a cellular network, in accordance with aspects of the M&G No. 50072.19WO0I/NC16582 invention. For purposes of this discussion the non-cellular interface will be a WLAN access network. Again, this non-cellular interface can be provided by any kind of non-cellular access network without departing from the spirit of this invention. As shown in the figure, network 300 includes four domains; Internet 315, Cellular Core Network 320, Cellular Access Network 330, and WLAN Access Network 325. Terminals TI 340, T2 345, T3 350, T4 355, T5 360, and T6 365.

WLAN Access Network 325 can be attached to the cellular network at different levels.

As shown in the figure, terminals (T1-T6) are paired together (TI and T2, T3 and T4, and T5 and T6) and show exemplary WLAN ad hoc links established (375, 380, and 385, respectively). Terminals TI, T2, and T3 use WLAN access network 325 for signaling. Terminals T4, T5, and T6 use cellular access network 330 for signaling.

The signaling for the purpose of secure and easy non-cellular ad hoc link establishment is transported to the cellular network. For WLAN-only terminals or dual mode terminals currently associated with WLAN access, the signaling is transported over the WLAN access network (T1-T2). For dual-mode, WLAN and cellular, the signaling for the terminals can be transported either over the WLAN link to WLAN access network or cellular link to cellular access network (T3-T4, T5-T6). Both terminals do not have to use the same access network for the signaling. For example, terminal T3 and terminal T4 use different access networks. Terminal T3 uses WLAN access network 425 and terminal T4 uses cellular access network 430.

The information transferred over the signaling link may include many different types of information. For example, the information may include user authentication, user ID retrieval (e.g., WLAN interface MAC address), security parameters, encryption keys and/or authorization and security association tokens allowing for secure WLAN ad hoc link establishment, radio resource management messages, and the like.

A multi-hop ad hoc network may also be implemented where users' connection is established locally aided by each user's control connection to the infrastructure as described above. (See FIGURE 4 and related discussion). To allow for an easy WLAN ad hoc link establishment, the peer's identifier is passed to the cellular network. The identifier could be the International Mobile Station Identity

9 M&G No. 50072.19WO01 NC16582 (IMSI) code (or equivalent) in WLAN terminal or in dual-mode terminal also in the non-WLAN part, user name (and operator), ISDN telephone number, network access identifier (NAI) or anything that can easily be communicated between users (verbal exchange of identities) or terminals (e.g., RF tags, identity broadcast over any medium, bar code, etc.).

FIGURE 4 illustrates a multi-hop signaling system that may be used in accordance with aspects of the invention. As illustrated in the figure, multi-hop signaling system 400 includes cellular infrastructure 405, terminal TI (410), terminal T2 (415), terminal T3 (420), access links to cellular infrastructure 425 and 430, and WLAN ad hoc links 435, and 440.

In order for some terminals to access the services provided by the cellular network, multi-hop signaling may be used. Terminals may not have direct access to the services provided by cellular infrastructure 405 for many reasons. For example, some terminals may only include a radio interface that is configured for a non-cellular network. Additionally, other terminals which are dual-mode terminals may be outside of the cellular network coverage. These dual-mode terminals, however, may be capable of connecting to a non-cellular network. Using the multi- hop signaling allows the terminals to reach the services provided by the cellular network according to this invention. As illustrated in the figure, terminal T3 (420) does not have direct access to cellular infrastructure 405. Terminal T3 may reach the services provided by cellular infrastructure, however, through terminal T2. Terminal T3 communicates with terminal T2 through WLAN ad hoc link (440). At some points in time, terminals TI (410) and T2 (415) are directly connected to the services provided by cellular infrastructure 405 through links 425 and 430. At other points in time, however, terminals may be outside of the cellular network coverage. In this situation, a terminal, such as terminal T2 (415) may still have an ad hoc link. According to this particular example, terminal T2 maintains a WLAN ad hoc link (435) with terminal TI. As can be seen, this multi-hop signaling allows terminals to reach the services provided by the cellular network

FIGURE 5 illustrates an operator controlled central register system, in accordance with aspects of the invention. As illustrated in the figure, central register system 500 includes mobile nodes TI 515, T2 520, T3 525, T4 530, and T5 535 and

10 M&G No. 50072.19WO0I/NC16582 central register 510. Terminals TI, T2, T3 and T4 are arranged such that they may communicate with each other using a non-cellular link. Terminal T5, however, uses a cellular link in its communication with terminals TI, T2, T3, and T4.

Mobile nodes, such as cellular phones, or PDA's with cellular cards, may utilize central register 510 operated a by an operator for organizing the ad hoc network and for routing the packets to a destination node. According to one embodiment of the invention, the mobile nodes in the network have both cellular (e.g. GPRS, GSM, UMTS) radio and non-cellular radio interfaces (e.g. Bluetooth, IR or WLAN). This operator may be the cellular operator for the users of the mobile node or a third party operator. The nodes in the ad hoc network have an option to use the operator-assisting service over the cellular radio, or try to manage without the service. According to one embodiment of the invention, the optional use of assistance is included in a routing algorithm in the nodes. When using the operator- assisted service, the nodes send regular update information of themselves over the cellular connection. The assisting service utilizes a standardized signaling scheme between the assisting servers and the mobile nodes. The standardized signaling scheme allows the nodes to communicate amongst themselves and the common operator. An advantage of the service is that the use of the service improves the quality of the ad hoc connection. Some of the services the operators may provide for the mobile nodes in the ad hoc network include: ad hoc network topology to assist in routing, service discovery, servers for ad hoc network applications like gaming or authentication, authorization and security functions, location related information, and the like. The scope of the service may be either micro-mobility within an ad hoc network link layer, in which case the macro-mobility in IP layer would be taken care by the mobile-IP, or both micro and macro-mobility, in which case it would be an alternative to mobile IP (Central Home agent operated by the operator).

As mentioned above, the mobile nodes send information about their neighbourhood to central register 510. For example, nodes within a Bluetooth neighbourhood may send update information to central register 510 when the nodes realize there has been a change in their neighbourhood. This change information of the neighbourhood may include e.g. information of new Bluetooth, WLAN or other ad hoc connections to new mobile phones or information of loosing a Bluetooth,

1 1 M&G No. 50072.19WO01/NC16582 WLAN or other ad hoc connection to certain mobile phones. Sending of information may be done via the cellular connection, which may be for example a GPRS, GSM or UMTS connection, or some other connection.

Based on the information received from the nodes by central register 510, central register 510 forms the description, or "the image" of the network. This description may be of any format suitable for describing the status and the layout of the network, especially the ad hoc parts of the network, which can then be used for determining the optimal route for each requested connection. More than one server may be used by the operator to perform the role of central register 510. According to this particular example, central register 510 will form a description of all Bluetooth, WLAN or other ad hoc connection capable nodes and their connections received from the mobile nodes (515, 520, 525, and 530).

When using the services provided by the cellular network, the nodes communicate by first asking assistance from the cellular network, i.e. a central register as in this example. Depending on the service and QoS of the node, the central register returns an answer optimized for the node, which can be either a single/multi hop connection route to the destination or a recommendation to use the cellular connection. This answer may comprise one or more messages, which may be signaling or data messages. The operator (or other third party organization) may charge for the operator controlled service. These operator controlled ad hoc communication services can be used for any local communication applications like local voice-, messaging-, file transfer- or other data services. As a specific example, Local Multimedia Messaging enables the use of non-cellular radio (such as Bluetooth) in a multimode cellular media phone for local multimedia messaging communications. When sending a multimedia message from a media phone, the client software contacts cellular network, in example a central register (such as a server) in the operator's network to check, whether the receiver is in a few hop environment in the non-cellular ad hoc network, and if so, sends the message over the non-cellular radio, instead of the cellular network.

The operator may, with a minimum investment, offer to users "free local multimedia messaging". This attracts users to the network and the users would familiarize with the multimedia messaging by sending them at first mainly locally.

12 M&G No. 50072.19WO0lfNCl6582 Users may also use the multimedia messaging over a cellular connection. This increased volume of normal multimedia messaging is a major benefit for the operator. According to one embodiment of the invention, the pricing of the service is based on the amount of assistance required by the cellular network. This operator-assisted service consumes a negligible part of cellular network capacity (<5% of the multimedia messaging traffic)

FIGURE 6 illustrates a process for ad hoc networking of terminals over a non-cellular interface aided by a cellular network, in accordance with aspects of the invention. After a start block, the process moves to block 605, at which point the process determines the identities of the terminals desiring to establish an ad hoc link. Transitioning to block 610, the process determines the networks associated with the terminals. For example, a terminal may be coupled to a non-cellular network, a cellular network, or both. Moving to block 620, a signaling method is chosen for the terminals. The signaling method is related to the networks the terminal is coupled too. For example, non-cellular only terminals, the signaling is transported over a non- cellular access network. For dual-mode terminals that may communicate over non- cellular and cellular networks, the signaling may be transported either over the non- cellular link to non-cellular access network or cellular link to cellular access network. Both terminals do not have to use the same access network for the signaling. For example, one terminal could use a non-cellular access network and another terminal may use a cellular access network. Flowing to block 630, a secure connection is established between the terminals with the aid of the cellular network. The information transferred over the signaling link to cellular network may include many different types of information. For example, the information may include user authentication, user ID retrieval and mapping (e.g., WLAN interface MAC address from MSISDN or RF Tag's address), security parameters allowing for secure non- cellular ad hoc link establishment, radio resource management messages, and the like. Transitioning to block 640, once the secure connection is established and the network is aware of the ad hoc non-cellular connection, the rules may be enforced. For example, the users of the terminals may be charged based on the flow of information and data between the terminals using the ad hoc non-cellular connection. The process then steps to an end block and returns to processing other actions.

13 M&G No. 50072.19WO01/NC16582 The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

1 4 M&G No. 50072.19WO01 NC16582