[0001] This invention relates to a mobile communication system in which a mobile platform is able to support multiple discrete communications links over different networks and/or frequency bands, such as satellite and terrestrial networks, and/or different satellite networks operating over different bands. Aspects of the invention include a terminal, satellite access station, terrestrial base or ground station, network control and other apparatus for use in such a system.

BACKGROUND

[0002] Combined satellite and terrestrial communication systems, such as Complementary Ground Component (CGC) or Ancillary Terrestrial Component (ATC) systems, are known in the art. Such systems provide integrated satellite and terrestrial links to mobile platforms. An example of such a system is disclosed in US 6,233,463.

[0003] Multi-band or hybrid satellite systems are also known, in which links are provided to a mobile platform over different satellite systems operating in different frequency bands. An example of such a hybrid system is disclosed in WO 2004/28034 Al.

[0004] US 8,606,266 discloses a data transmission system in which an airborne user terminal is able to communicate over either a first or a second data network, the second data network having more contiguous physical coverage than the first network. A proxy unit on the aircraft is configured to select routing via the first or second network based on a user condition, such as user preference, type of user session or travel path of the user.

STATEMENT OF THE INVENTION

[0005] According to one aspect of the present invention, there is provided a mobile communication system, comprising: a mobile platform having a plurality of interfaces to a respective plurality of mobile communication networks, and a router for selectively connecting one or more communications devices within the mobile platform to one or more of the interfaces, for communication over the respective mobile communication networks; and a central core common to each of the mobile communication networks, comprising a policy master arranged to determine resource requirements within the mobile communication networks in accordance with one or more defined policies and a resource manager arranged to allocate resources to the mobile communication networks in response to resource requests from the router and to resource requests from the policy master.

[0006] The resource manager may control which of the link interfaces are active at any one time and/or may vary the communication resources available through each of the link interfaces. The allocation of communication resources may be varied dynamically. The resource ma nager may apply one or more predetermined rules or heuristics based on a number of conditions, including but not limited to the nature of the resource requests, the conditions or available capacity within the mobile communication networks, the current or future position of the mobile platform, or cost, energy, latency or efficiency requirements.

[0007] The resource manager may be located within a Network Operations Centre (NOC). The resource manager may be responsive to network metrics and parameters, for example provided by Network Management Station (NMS).

[0008] The router may select different interfaces for uplink and downlink communications. The router may select more than one of the interfaces for simultaneous communications.

[0009] The mobile platform may comprise an aeronautical platform or a maritime platform, for example. The mobile platform may include a local network for connecting a plurality of on-board devices to the router. The local network may be a wired and/or wireless network.

[0010] Aspects of the invention include the mobile platform, the router and the resource manager.

[0011] Aspects of the present invention are defined with reference to the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic diagram of the on-board elements of a communication system according to an embodiment of the present invention;

Figure 2 is a network diagram of the communication system in the embodiment; and

Figure 3 is a ladder diagram illustrating examples of the operation of the system of the embodiment. DESCRIPTION OF EMBODIMENTS

[0013] Figure 1 illustrates a system in which a plurality of radio interfaces 2 are installed on an aircraft 1, including satellite interfaces 2a, 2b, 2c to one or more satellite communications networks, such as:

a high-speed data communications network such as the Inmarsat (RTM) Global Xpress (RTM) (GX) network which uses Ka-band spectrum for communication with the lnmarsat-5 satellite(s).

an 'always-on' data network such as the Inmarsat (RTM) Swift Broadband (RTM) (SBB) network, which provides an IP-based packet switched global service based on the BGAN service, using L-band spectrum for communication with the lnmarsat-4 satellites.

the satellite component of a hybrid satellite/terrestrial network, such as the proposed Inmarsat S-band satellite network (S-Comm), which will provide communication with one or more satellites using the S-band spectrum.

[0014] The interfaces 2 may include one or more interfaces 2d to terrestria l communication networks, for example the terrestrial component of a hybrid satellite/terrestrial network such as the Inmarsat Aviation Complementary Ground

Component (ACGC) of the proposed Inmarsat S-band service. Preferably, some or all of the satellite and/or terrestrial interfaces 2 are bidirectional.

[0015] The above interfaces 2 are connected to on-board equipment (OBE) within the aircraft 1, for example to an Aircraft Cabin Network (ACN) 3 for providing connectivity to various client devices 4, which may include personal devices belonging to the passengers or crew, and cockpit and/or cabin communication or In-flight Entertainment (IFE) systems. The ACN 3 may comprise wireless and/or wired LANs.

[0016] In the system according to this embodiment, one or more of the interfaces 2 may be configured or combined to provide connectivity to the client devices 4 in the most efficient and cost-effective manner, for example so to provide an optimum Quality of Experience/Service (QoE/QoS), taking account of any cost constraints, using capacity in one or more of the corresponding networks. Different interfaces 2 may be used respectively for the uplink (i.e. from the aircraft) and downlink (i.e. to the aircraft) for the same communication session and/or device 4, or for the communications traffic to/from the ACN 3 as a whole.

[0017] Examples of such configurations and combinations are shown in Table 1 below:

Table 1 - Communication Link Examples

[0018] As shown in Table 1 above, more than one interface 2 may be active simultaneously, giving aggregate multi-network connectivity to the ACN 3 and/or to individual devices 4. The multi-network connectivity is managed by a management system that is preferably distributed between the aircraft 1 and the external network, as shown for example in Figure 2.

[0019] Figure 2 shows the overall network architecture of the system. The interfaces 2a, 2b, 2c, 2d are connected to respective networks 6a to 6d, each having an associated Radio Access Node (RAN) 7a, 7b, 7c, 7d. Each of the networks 6 is connected to a common central core 10, containing a Global Resource Manager (GRM) 11 and a Network Operations Centre (NOC) 12, as well as other network elements such as Policy and Charging Rules Function (PCRF) 13, Mobility Management Entity (MME) 14, Serving Gateway (SGW) 18, Packet Gateway (PGW) 15, Home Subscriber Server (HSS) 16 and Satellite Core 17. The common central core 10 interfaces with service platform(s) 20, such as public Internet access 21, airline administrative portal 22, and application and service hosting 23 including service delivery platform (SDP) 24. The common central core also interfaces with a network management system (NMS) station 25.

[0020] The multi-network connectivity is preferably managed by a policy master located within the common core 10 and a policy slave located on board the aircraft 1. The policy master may reside at the NOC 12, and the policy slave may be a service- aware router (SAR) 5 connected to, or forming part of the ACN 3.

[0021] The policy master implements heuristics or rules to request assignment of resources with the aim of providing optimum QoE. The policy slave is able to drive at least some of the policy decision rules and to request capacity for its connected devices 4. The policies governing the assignment of resources may include one or more of:

- Service type requested

Requested committed information rate (CIR) and maximum information rate

(MIR)

Guaranteed access policy

Radio link availability for the onboard radio link interfaces

- Utilisations/loading of available links/networks Latencies of available links/networks

Least cost route (e.g. in terms of number of hops and/or cost per unit of data) Radio link qualities

Position of the aircraft 1, determined for example by satellite navigation systems such as GPS and/or GLONASS

Time of the day

Route of the flight

Special events in time and geography (e.g. disruptions)

Energy efficiency requirements

- Communication reliability requirements

Number of passengers/devices with active session onboard

[0022] The NMS 25 collects statistics relevant to QoE/QoS, radio link utilisation, availability, quality and other parameters and provides useful metrics and feedback to the NOC 12. The NOC 12 uses this feedback to adjust/optimise Radio Resource Management (RRM) dynamically, for example in real-time. The NOC 12 then requests the Global Resource Manager (GRM) 11 to assign capacity to the various networks 6 so as to provide resources to the various interfaces 2 on board the aircraft 1, via the corresponding RAN 7. The NOC 12 and GRM 11 work together to allocate capacity on demand to the networks 6 to serve the real time demand, making use of the information provided by the NMS 25. Note that the capacity allocated to the RAN 7 may be a proportion of the available spectrum and need not correspond to specific channels. The RAN 7 may in turn allocate specific channels to the interfaces 2 utilizing the available spectrum.

[0023] The policy master, being located within the common central core 10, is optimally positioned to determine an overall allocation policy across the different networks 6. The policy slave, being connected locally to the ACN 3 and the interfaces 2, is optimally positioned to respond to local demand from the devices 4 and local conditions pertaining to the aircraft 1.

[0024] In alternative embodiments, the decision-making function may be shifted towards the SAR 5. For example, the NOC 12 may report network conditions to the SAR 5, which may then request capacity for the interfaces 2 based in part on the network conditions. However, it is more efficient to centralise decision-making relating to network conditions at the central core 10, for example at the NOC 12.

[0025] Conversely, the decision-making function may be shifted towards the central core 10/NOC 12. For example, the SAR 5 may report demand and other conditions, and all capacity and link allocations may be made by the central core 10/NOC 12.

[0026] Examples of the operation of the system are shown in the ladder diagram of Figure 3, illustrating the basic nominal interactions between the network nodes and the OBE in order to provide optimum connectivity on board the aircraft 1. The diagram shows two examples sequentially: an OBE-initiated capacity request, and a network- initiated capacity assignment.

[0027] In the OBE-initiated capacity request, at step SI the interfaces 2 declare their availability to the SAR 5. At step S2, the NOC 12 initialises the interfaces 2 with the required provisioning and authorisations. At step S3, the SAR 5 responds to traffic demand (e.g. from the devices 4) by sending a request via the RAN 7 to the NOC 12 to use one or more of the interfaces 2. At step S4 the NOC 12 authorises the use of the requested interface(s) 2 and informs the GRM 11, the NMS 25 and the RAN associated with the requested communications networks 6. At step S5, the RAN requests capacity for the requested interfaces 2 from the GRM 11. At Step S6, the GRM 11 assigns capacity to the SAR 5 for the requested links, via the RAN, informing NMS 25. At step S7, communications traffic is exchanged using the assigned capacity, monitored by the NMS 25.

[0028] In the network-initiated capacity assignment, at step S7 the policy master at the NOC 12, informed by the NMS 25, detects a change in the capacity required for communication with the OBE. Based on global availability and demand for capacity, at step S8 the policy master then authorises a variation in the network links and/or capacity used by the OBE and requests a variation in capacity over the relevant links from the GRM 11. At step S9 the GRM 11 grants the requested capacity to the RAN 7, informing the NMS 25. At step S10, the SAR 5 performs load balancing between the plurality of interfaces 2 now available to the OBE, allowing simultaneous bidirectional communications over each of the available interfaces 2.

[0029] The above embodiment is described with reference to an aeronautical mobile platform, but is also applicable to other types of mobile platforms, such as a maritime platform on a ship. The maritime platform may equally utilize a plurality of radio interfaces including satellite and terrestrial links and operate in similar fashion as the aircraft in Figure 1 over a plurality of mobile communications networks in similar fashion as Figure 2, whereby examples of operation are shown in Figure 3.

[0030] Many alternative embodiments may be envisaged, which nevertheless fall within the scope of the invention as defined by the claims. It is understood that protection is sought hereby for any and all novel subject matter and combinations thereof disclosed herein. Unless the contrary is stated, features of each embodiment may be combined with features of any other.