Deep space network convergence networking architecture and domain-division networking method, system and equipment

Abstract

The invention discloses a deep space network convergence networking architecture and a domain division networking method, system and device, and relates to the technical field of deep space networking, and the method comprises the steps: a planetary access network node in a planetary domain adopts a standard TCP / IP protocol stack, a satellite network node in the planetary domain adopts an ad-hoc network protocol based on a global unique identifier, and the satellite network node in the planetary domain adopts an ad-hoc network protocol based on a global unique identifier; data aggregation in a planetary domain and cross-planetary domain access are realized through an interstellar gateway; the interstellar backbone domain takes a deep space intelligent router deployed on a deep space orbit as interstellar backbone network nodes, the interstellar backbone network nodes are transmitted through a deep space fusion protocol, and the deep space fusion protocol allocates a unique backbone domain code for each interstellar backbone network node and maintains a dynamic routing table; the two or more planetary domains are in cross-domain transmission through the interstellar backbone domain; according to the deep space network convergence networking architecture and the domain-divided networking method, system and equipment, heterogeneous deep space network convergence and data transmission are realized.

Description

Technical Field

[0001] The present invention relates to the field of deep space network networking technology, and in particular to a deep space network integrated networking architecture and domain-specific networking methods, systems, and devices. Background Art

[0002] The Deep Space Network (DSN) is the space infrastructure supporting deep space exploration missions and a crucial foundation for human interplanetary exploration. Compared to near-Earth satellite networks, the DSN's extreme long-range, high latency, and extremely low bandwidth make its networking and transmission challenging. Compared to near-Earth satellite networks, the DSN relies on extremely low bandwidth for data transmission. Therefore, the DSN's extreme long-range, high latency, and low bandwidth preclude direct reuse of existing near-Earth satellite network routing and transmission technologies. Furthermore, factors such as celestial obstruction and space radiation further reduce the efficiency and reliability of DSN transmission.

[0003] To enhance the data transmission capabilities of deep space exploration missions, deploying multiple deep space interstellar backbone network nodes to connect access networks and deep space exploration equipment on different planets is widely recognized as a future deep space network architecture. The deep space interstellar backbone network provides interplanetary data routing and transmission services, shortening the single-hop communication distance in deep space to a certain extent while reducing link intermittency caused by celestial obstruction. However, deep space networks based on planetary access networks and interstellar backbone networks still face many challenges in terms of efficient routing and transmission. The different networks covered by deep space networks, such as the surface network, planetary access network, and interstellar backbone network, are highly heterogeneous and dynamic, and the development of cross-planetary deep space networking architectures and fusion protocols is urgently needed. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a deep space network fusion networking architecture and a domain-based networking method, system and equipment to achieve heterogeneous deep space network fusion and data transmission.

[0005] The deep space network fusion networking architecture and domain-based networking method proposed in the present invention include: The planetary access network nodes in the planetary domain use the standard TCP / IP protocol stack, and the satellite network nodes in the planetary domain use the self-organizing network protocol based on the global unique identifier, and realize the data aggregation within the planetary domain and cross-planetary domain access through the interstellar gateway; The interstellar backbone domain uses deep space intelligent routers deployed in deep space orbit as interstellar backbone network nodes. The interstellar backbone network nodes transmit information through the deep space fusion protocol. The deep space fusion protocol assigns a unique backbone domain code to each interstellar backbone network node and maintains a dynamic routing table. The entries in the dynamic routing table are indexed by the planet domain code and record the list of reachable interstellar gateways and the link status of the interstellar gateways. Cross-domain transmission between two or more planetary domains is achieved through the interstellar backbone domain.

[0006] Further, the TCP / IP protocol is used for routing between the planetary access network node and the interstellar gateway, and the deep space fusion protocol is used for routing between the interstellar backbone network nodes in the interstellar backbone domain; A protocol conversion module is provided in the interstellar gateway for dynamically mapping TCP / IP addresses to the globally unique identifiers of satellite network nodes.

[0007] Further, the identification structure of the dynamic routing table includes a planetary domain code, a backbone domain code, a node type, a sub-domain ID, and the globally unique identifier of the satellite network node.

[0008] Further, the header setting of the deep space fusion protocol includes inherent information, address information, cyclic redundancy check code, and carried payload; The inherent information includes a version number, a protocol type, a service type, a payload offset, and a payload size; The address information includes a source globally unique identifier, a source network address, a destination globally unique identifier, and a destination network address.

[0009] Further, each satellite network node is assigned a globally unique identifier, which is transmitted as part of the data packet header. When the data packet reaches the interstellar backbone network node connected in the interstellar backbone domain, the source globally unique identifier of the satellite network node is extracted from the data packet header, and the interstellar backbone network node obtains the destination network address therefrom, and then forwards the data packet to the next hop.

[0010] Further, the realization of data aggregation within the planetary domain and cross-planetary domain access through the interstellar gateway is specifically as follows: Within the planetary domain, the satellite network node periodically broadcasts a beacon message containing the globally unique identifier. The interstellar gateway estimates the orbital change of the satellite network node according to the signal strength and Doppler frequency shift, and updates the local identifier-location mapping table in the interstellar gateway, so as to realize data aggregation within the planetary domain; In the cross-planetary domain scenario, in the original planetary domain, the original interstellar gateway marks the "planetary domain code" field of the globally unique identifier as "transition state", and pre-registers a temporary identifier to the target planetary domain through the interstellar backbone network node, and establishes a two-way tunnel to forward traffic until the planetary network node completes domain switching, so as to realize cross-planetary domain access.

[0011] Further, the interstellar backbone network node adopts a hybrid routing strategy, specifically: For delay-sensitive traffic, use a source preset path based on the globally unique identifier, and inject the path node coding sequence in advance; For delay-tolerant traffic, adopt a store-and-forward mode.

[0012] Furthermore, the internal topological changes in the planetary domain are encapsulated within the domain, and only the planetary domain code and the interstellar gateway are exposed externally.

[0013] Furthermore, it includes an interstellar backbone domain and a planetary domain. The planetary domain includes planetary access network nodes and satellite network nodes orbiting the planet. Cross-domain transmission between two or more planetary domains is achieved through the interstellar backbone domain. The planetary access network nodes adopt the standard TCP / IP protocol stack, and the satellite network nodes adopt the ad-hoc network protocol based on the globally unique identifier. Data aggregation within the planetary domain and cross-planetary domain access are achieved through the interstellar gateway. The interstellar backbone domain uses deep space intelligent routers deployed on deep space orbits as interstellar backbone network nodes. The interstellar backbone network nodes transmit through the deep space fusion protocol. The deep space fusion protocol assigns a unique backbone domain code to each interstellar backbone network node and maintains a dynamic routing table. The entries in the dynamic routing table are indexed by the planetary domain code and record the list of reachable interstellar gateways and the link status of the interstellar gateways.

[0014] A computer device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method is implemented.

[0015] The advantages of the deep space network fusion networking architecture, sub-domain networking method, system, and device provided by the present invention are as follows: For the problem of cross-planetary fusion networking of high-dynamic deep space heterogeneous networks, a globally unique identifier of the device is introduced, a deep space sub-domain networking architecture with built-in mobility support is proposed, deep space intelligent routers and interstellar gateways are designed to achieve deep space fusion networking covering the surface network, planetary access network nodes, interstellar backbone network nodes, and external networks; for the fusion networking problems caused by the significant heterogeneity and high dynamics of deep space networks, this embodiment introduces a globally unique identifier of the device, proposes a deep space sub-domain networking architecture with built-in mobility support and an identity-based deep space fusion protocol to achieve heterogeneous deep space network fusion and data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic flow chart of the present invention; Figure 2 It is a schematic diagram of the deep space network architecture; Figure 3 It is a schematic diagram of data transmission in the deep space network; Figure 4 It is a schematic diagram of the identification structure of the dynamic routing table; Figure 5 It is a schematic diagram of the header of the deep space fusion protocol; Figure 6 It is a schematic diagram of the conversion between the deep space fusion protocol based on the interstellar gateway and the TCP / IP protocol. Detailed implementation manners

[0017] Next, the technical solutions of the present invention will be described in detail through specific embodiments. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0018] As Figures 1 to 6 shown, the deep space network fusion networking architecture and domain-based networking method proposed by the present invention include: Step 1: The planetary access network nodes in the planetary domain adopt the standard TCP / IP protocol stack, and the satellite network nodes in the planetary domain adopt the self-organizing network protocol based on the globally unique identifier. Data aggregation within the planetary domain and cross-planetary domain access are realized through the interplanetary gateway. Step 2: The interstellar backbone domain uses the deep space intelligent router deployed on the deep space orbit as the interstellar backbone network node. The interstellar backbone network nodes transmit through the deep space fusion protocol. The deep space fusion protocol assigns a unique backbone domain code to each interstellar backbone network node and maintains a dynamic routing table. The entries in the dynamic routing table are indexed by the planetary domain code and record the reachable interplanetary gateway list and the link status of the interplanetary gateway.

[0019] Step 3: Cross-domain transmission between two or more planetary domains is realized through the interstellar backbone domain.

[0020] Aiming at the fusion networking problem caused by the significant heterogeneity and high dynamicity of the deep space network, this embodiment focuses on the design of the deep space network fusion networking architecture and proposes a deep space domain-based networking method based on the globally unique identifier (Global Unique Identifier, GUID). By establishing a global identity identification mechanism for deep space nodes, a multi-level networking system covering the surface sensing layer, planetary access layer, and interstellar backbone layer is constructed. On this basis, aiming at the cross-planetary network interconnection requirement, the compatibility limit of the traditional protocol stack is broken through, and a cross-domain interoperability framework that supports the fusion of the Delay-Tolerant Networking (DTN) and the Consultative Committee for Space Data Systems (CCSDS) protocol is designed. The key is to overcome the deep space heterogeneous protocol conversion and realize the global interconnection of the deep space network, the ground Internet, and the planetary surface sensor network.

[0021] This embodiment also proposes a deep - space fusion protocol based on identity identification to achieve heterogeneous deep - space network fusion. The core lies in using a globally unique identifier for routing. Different satellite network nodes will be assigned a globally unique identifier, which will be transmitted as part of the data - packet header. When the data packet reaches the backbone network node in the interstellar backbone domain, the header needs to be parsed to extract the source globally unique identifier of the satellite network node from the data - packet header. The interstellar backbone network node obtains the destination network address based on this and then forwards the data packet to the next hop.

[0022] Based on the mapping between the globally unique identifier of the satellite network node and the network address, this embodiment further designs the transmission mechanism of the deep - space fusion protocol in heterogeneous networks and the conversion with existing protocols.

[0023] In one of the embodiments, the cross - planetary deep - space network fusion networking architecture design is as follows: There are problems such as dynamic changes in node positions and communication occlusion in deep - space networks. For this reason, this embodiment proposes a mobility - supported deep - space sub - domain networking architecture, in which the network node identifier (Global Unique Identifier, GUID) is decoupled from the network address (Network Address, NA), and a distributed space - based GUID - NA resolution system is implemented for location management. To address communication interruption and communication occlusion problems, this embodiment sets up deep - space intelligent routers and interplanetary fusion gateways to ensure continuous communication.

[0024] The deep - space sub - domain networking architecture is as Figure 2 shown. Its basic concept is to apply Internet technology in the planetary access network with lower latency, use the interstellar backbone network with long latency to connect distributed planetary access networks, and establish an interstellar fusion gateway for low - latency and high - latency networks.

[0025] Aiming at the cross - planetary networking requirements of high - dynamic deep - space heterogeneous networks, this embodiment solves the interconnection problems of long latency, high - dynamic topology, and multi - protocol heterogeneous networks in the deep - space environment through hierarchical domain division, structured identification system, and dynamic mobility support. This architecture divides the deep - space network into three major levels: the planetary domain, the interstellar backbone domain, and the external domain. The planetary domain consists of planetary access network nodes and satellite network nodes orbiting the planet. Among them, the planetary access network nodes follow the standard TCP / IP protocol stack to be compatible with existing ground devices, while the satellite network nodes adopt a self - organizing protocol based on globally unique identifiers to achieve in - domain data aggregation and cross - domain access through the interstellar gateway.

[0026] As the core node within the planetary domain, the Interstellar Gateway is built with a protocol conversion module that can dynamically map TCP / IP addresses to the globally unique identifiers of satellite network nodes (e.g., map IP 192.168.1.1 to a 128-bit identifier with a planetary domain code of 0x01 and a device type of 0x02). Meanwhile, it maintains the topological state within the planetary domain (i.e., internal topological changes within the planetary domain are encapsulated within the domain), and only exposes the planetary domain code and the Interstellar Gateway identifier externally, thus shielding local topological changes caused by satellite orbit migrations or ground node movements.

[0027] Since different protocols are used by planetary access network nodes and interstellar backbone network nodes to determine the destination network address, protocol conversion is inevitably involved in the data forwarding process. As Figure 6 shown, the IP protocol is used between planetary access network nodes and the Interstellar Gateway. After the data passes through the Interstellar Gateway, the Deep Space Fusion Protocol is used on the way to another Interstellar Gateway. Only the Deep Space Fusion Protocol is used between the routing and forwarding nodes of the interstellar backbone network nodes, and the Interstellar Gateway is responsible for the conversion between the IP protocol and the Deep Space Fusion Protocol. This protocol conversion mechanism based on the Interstellar Gateway can effectively be compatible with traditional IP protocols and improve the scalability of network protocols.

[0028] The settings of the Interstellar Gateway have the following key innovations: 1) Protocol isolation layer: Through the protocol conversion module of the Interstellar Gateway, two-way transparent intercommunication between the standard TCP / IP protocol and the Deep Space Fusion Protocol is achieved, and surface devices can access the deep space network of the interstellar backbone domain without modification; 2) Dynamic topology abstraction: Internal topological changes within the planetary domain (such as satellite orbit adjustments, rover movements on Mars) are encapsulated within the domain, and external communication only depends on the stable planetary domain code; 3) Mobility prediction mechanism: Combining the Doppler frequency shift and orbit prediction algorithms, the local identifier-location mapping table is updated in advance to reduce handover latency.

[0029] This deep space sub-domain networking architecture essentially constructs a "deep space overlay network" that, while retaining the compatibility of existing surface facilities, addresses the core challenges of the deep space environment through structured identification and intelligent routing, laying the foundation for the future interstellar Internet.

[0030] The interstellar backbone domain is composed of deep space intelligent routers deployed in deep space orbit. Its core function is to realize cross-planetary domain routing addressing through structured globally unique identification. Each deep space intelligent router is assigned a unique backbone domain code (16 bits) and maintains a dynamic routing table. The entries in the table are indexed by the planetary domain code (32 bits) to record the list of reachable interstellar gateways and their link status (for example, the Earth domain 0x01 corresponds to the three deep space routers in the orbit of Mars). The identification structure of the dynamic routing table adopts a five-segment 128-bit fixed-length format, including the planetary domain code, backbone domain code, node type (8 bits to distinguish satellite / gateway / probe, etc.), subdomain ID (24 bits to identify the orbital layer or ground subnet) and the globally unique identifier of the satellite network node (48 bits). The identification structure of the dynamic routing table is as follows Figure 4 shown.

[0031] To support cross-domain node mobility, the architecture designs a two-level location management mechanism: within the planetary domain, satellite network nodes periodically broadcast beacon messages containing a globally unique identifier. The interstellar gateway estimates its orbital changes based on signal strength and Doppler frequency shift, and updates the local identifier-location mapping table. In cross-planetary domain scenarios (such as a probe flying from the Earth domain to the Mars domain), the original interstellar gateway marks the "planetary domain code" field of the globally unique identifier as "transitional state" and pre-registers a temporary identifier with the target planetary domain (such as Mars) through the backbone domain router, establishing a bidirectional tunnel to forward traffic until the planetary network node completes the domain switch.

[0032] The deep space intelligent router (interstellar backbone network node) adopts a hybrid routing strategy: it uses identity-based source routing for delay-sensitive traffic (such as telemetry instructions) and injects the path node coding sequence in advance; it adopts the store-and-forward mode for delay-tolerant traffic (such as scientific data).

[0033] For a probe traveling from Earth to Mars, the specific steps for interplanetary domain movement are as follows: 1) Pre-registering a temporary identifier: When the probe leaves the Earth domain, the source Earth interstellar gateway marks the planetary domain code in its globally unique identifier as transitional. It then sends a pre-registration request to the Mars domain via the backbone router, assigning the probe a temporary Mars domain code (pre-registered temporary identifier). 2) A dedicated tunnel is established between the Earth and Mars domains, with the two ends of the tunnel mapping (Earth domain globally unique identifier to Mars domain temporary identifier). After the probe enters the Mars domain, its broadcast beacon is captured by the Mars interstellar gateway, which activates its temporary identifier, updates its routing table, and dismantles the tunnel. Data sent to the probe is encapsulated by the Earth interstellar gateway through the tunnel and forwarded to the Mars interstellar gateway via the interstellar backbone domain. Data sent from the probe is transmitted back to the Earth interstellar gateway via the tunnel by the Mars interstellar gateway, and then returned along the original path.

[0034] In one embodiment, the deep space fusion interconnection protocol message design is specifically as follows: The data packet header of the deep space fusion interconnection protocol designed in this embodiment is as follows Figure 5 shown, and it can be divided into four parts: inherent information, address information, cyclic redundancy check code (CRC), and carried payload. The inherent information is 12 bytes in total. After removing 2 bytes of reserved fields, the remaining 10 bytes are respectively: version number, protocol (protocol type), service type (unicast, multicast, etc.), payload offset, and payload size. Then comes the 16-byte address information, which is mainly used for routing and includes source unique identifier, source network address, destination unique identifier, and destination network address, with each address being 4 bytes. At the end are the CRC code and the carried payload.

[0035] In one of the embodiments, the deep space fusion protocol transmission mechanism is specifically as follows: The network address mapper in the control plane part of the deep space fusion protocol can be used to support the deep space fusion protocol service in the data plane, and find its corresponding network address through the globally unique identifier. In the interstellar backbone domain, the destination network address is obtained through the globally unique identifier of each satellite network node, and at the same time, a suitable planetary access network node is searched for. In each planetary access network node, the basic TCP / IP protocol is used for forwarding. An example of the transmission process is as follows Figure 3 shown. The earth access network node (planetary access network node) transmits data to the planetary A access network node. Among them, when the earth access network node (planetary access network node) transmits to the interstellar gateway N1 and when the interstellar gateway N2 transmits to the planetary A access network node (planetary access network node), only the TCP / IP protocol is used for routing, while when the interstellar gateway N1 transmits to the interstellar gateway N2, the deep space fusion protocol is used for routing (marked by the purple dashed line in the figure), that is, each planetary access network node uses the TCP / IP protocol for transmission, while the interstellar backbone network node uses the deep space fusion protocol for transmission.

[0036] This embodiment aims at the problem of cross-planetary fusion networking in high-dynamic deep space heterogeneous networks, introduces the device globally unique identifier, proposes a deep space domain-based networking architecture with built-in mobility support, designs deep space intelligent routers and interstellar gateways, and realizes deep space fusion networking covering the surface network, planetary access network nodes, interstellar backbone network nodes, and external networks; aiming at the fusion networking problems caused by the significant heterogeneity and high dynamicity of deep space networks, this embodiment introduces the device globally unique identifier, proposes a deep space domain-based networking architecture with built-in mobility support and an identity-based deep space fusion protocol, and realizes the fusion of heterogeneous deep space networks and data transmission.

[0037] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. Deep space network integrated networking architecture and domain-based networking method, characterized in that including: The planetary access network nodes in the planetary domain adopt the standard TCP / IP protocol stack, and the satellite network nodes in the planetary domain adopt the self-organizing network protocol based on the globally unique identifier, and realize data aggregation within the planetary domain and cross-planetary domain access through the interstellar gateway; The interstellar backbone domain uses the deep space intelligent router deployed on the deep space orbit as the interstellar backbone network node. The interstellar backbone network nodes transmit through the deep space fusion protocol. The deep space fusion protocol assigns a unique backbone domain code to each interstellar backbone network node and maintains a dynamic routing table. The entries in the dynamic routing table are indexed by the planetary domain code and record the reachable interstellar gateway list and the link status of the interstellar gateway; Cross-domain transmission between two or more planetary domains is realized through the interstellar backbone domain.

2. The deep space network integrated networking architecture and domain-based networking method according to claim 1, wherein The TCP / IP protocol is used for routing between the planetary access network node and the interstellar gateway, and the deep space fusion protocol is used for routing between the interstellar backbone network nodes in the interstellar backbone domain; A protocol conversion module is set in the interstellar gateway for dynamically mapping the TCP / IP address and the globally unique identifier of the satellite network node.

3. The deep space network integrated networking architecture and domain-based networking method according to claim 1, characterized in that The identification structure of the dynamic routing table includes the planetary domain code, the backbone domain code, the node type, the sub-domain ID, and the globally unique identifier of the satellite network node.

4. The deep space network integrated networking architecture and domain-based networking method according to claim 1, wherein The header setting of the deep space fusion protocol includes inherent information, address information, cyclic redundancy check code, and carried payload; The inherent information includes version number, protocol type, service type, payload offset, and payload size; The address information includes the source globally unique identifier, the source network address, the destination globally unique identifier, and the destination network address.

5. The deep space network integrated networking architecture and domain-based networking method according to claim 4, characterized in that Each satellite network node is assigned a globally unique identifier, which will be transmitted as part of the data packet header. When the data packet arrives at the interstellar backbone network node connected in the interstellar backbone domain, the source globally unique identifier of the satellite network node is extracted from the data packet header. The interstellar backbone network node obtains the destination network address based on this and then forwards the data packet to the next hop.

6. The deep space network integrated networking architecture and domain-based networking method according to claim 1, wherein The realization of data aggregation within the planetary domain and cross-planetary domain access through the interstellar gateway is specifically as follows: Within the planetary domain, the satellite network node periodically broadcasts a beacon message containing the globally unique identifier. The interstellar gateway estimates the orbital change of the satellite network node according to the signal strength and Doppler frequency shift, and updates the local identifier-location mapping table in the interstellar gateway, so as to realize data aggregation within the planetary domain; In the cross-planetary domain scenario, in the original planetary domain, the original interstellar gateway marks the "planetary domain code” field of the globally unique identifier as "transition state”, and pre-registers a temporary identifier to the target planetary domain through the interstellar backbone network node, and establishes a two-way tunnel to forward traffic until the planetary network node completes the domain switch, so as to realize cross-planetary domain access.

7. The deep space network integrated networking architecture and domain-based networking method according to claim 1, characterized in that The interstellar backbone network node adopts a hybrid routing strategy, specifically: For delay-sensitive traffic, use the source preset path based on the globally unique identifier and inject the path node coding sequence in advance; For traffic with tolerable delay, adopt the store-and-forward mode.

8. The deep space network integrated networking architecture and domain-based networking method according to claim 1, characterized in that The internal topology change of the planetary domain is encapsulated within the domain, and only the planetary domain code and the interstellar gateway are exposed externally.

9. Deep space network integrated networking architecture and domain-based networking system, characterized in that, It includes an interstellar backbone domain and planetary domains. The planetary domains include planetary access network nodes and satellite network nodes orbiting the planets. Cross-domain transmission between two or more planetary domains is achieved through the interstellar backbone domain; The planetary access network nodes adopt the standard TCP / IP protocol stack, and the satellite network nodes adopt the ad hoc network protocol based on the globally unique identifier. Data aggregation within the planetary domain and cross-planetary domain access are achieved through the interstellar gateway; The interstellar backbone domain uses deep space intelligent routers deployed on deep space orbits as interstellar backbone network nodes. The interstellar backbone network nodes transmit through the deep space fusion protocol. The deep space fusion protocol assigns a unique backbone domain code to each interstellar backbone network node and maintains a dynamic routing table. The entries in the dynamic routing table are indexed by the planetary domain code and record the list of reachable interstellar gateways and the link status of the interstellar gateways.

10. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method described in any one of claims 1-8.

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