Patent Description:
In the prior art, a satellite backhaul network routes all traffic types to one specific destination. In the prior art, the traffic destination is not separated by traffic types such as voice or data. <CIT> describes a method of transmitting bursty data and non-bursty data, the method including using terrestrial networks to transmit the non-bursty data and sharing satellite bandwidth to transmit the bursty data from multiple sites, the non-bursty data and the bursty data are transmitted concurrently via the terrestrial networks and the satellite bandwidth, respectively, the bursty data is non-voice data with bursty characteristics.

<FIG> illustrates a prior art cellular system.

A typical LTE cellular system <NUM> is shown in <FIG>. The Evolved Packet Core (EPC) Core Network (CN) includes an MME (or MMEs), a Serving Gateway (SGW) and a PDN (Packet Data Network) Gateway (PGW). An Enhanced Node B (eNB) communicates with an MME for signaling and a Serving Gateway (SGW) for user traffic. All User Terminal (UT) traffic goes through the SGW/PGW to its destination. The traffic from the UT (user traffic) may include voice traffic and data traffic. The PGW forwards voice traffic to a Media Gateway (MGW), in the IP Multimedia Subsystem (IMS), that provides communications with a Public Switched Telephone Network (PSTN). The PGW forwards the data traffic to an external network, such as, the Internet.

3GPP standardizes the all-IP network called Long Term Evolution (LTE) cellular network. LTE provides faster rate than its predecessor such as <NUM> cellular network. In LTE, all user traffic, namely voice and data, is carried as IP traffic. The LTE core network is called Evolved Packet Core (EPC). EPC includes myriad functions, such as, a serving gateway (SGW) to connect to the access network, i.e., eNB; a packet gateway (PGW or sometimes PDN-GW) to interconnect to the external IP networks such as the Internet and an IP multimedia subsystem (IMS); a mobility management entity (MME) to deal with the control plane and signaling; and the home subscriber server (HSS) to facilitate subscriber-related information. The connection between PGW and external IP network is provided by the SGi interface.

Cellular backhaul over a satellite backhaul provides connectivity of eNBs in underserved areas (rural locations, islands, etc.) to telephone and internet networks deployed in centrally developed locations (urban locations, cities, etc.). Due to the delay incurred over the satellite backhaul and limited radio resources, the user experience for voice and data traffic over the satellite backhaul as compared to low latency and high bandwidth terrestrial links is inferior.

<FIG> illustrates a prior art cellular system using a satellite backhaul as backhaul carrier.

A prior art cellular system <NUM> may include a satellite backhaul <NUM> as a backhaul carrier. In system <NUM>, the traffic between the eNB and the EPC is carried as backhaul traffic using the satellite backhaul <NUM> including a Very Small Aperture Terminal (VSAT), a satellite, and a VSAT Gateway (VSAT GW). The eNB is connected to the VSAT and the EPC is connected to a VSAT GW to provide connectivity. In the network configuration of <FIG>, the PGW filters all UT traffic and sends it to a specific destination, for example, voice and its associated signaling is sent to an MGCF/MGW and data and its associated signaling is sent to the Internet.

The present teachings disclose integration of cellular and satellite backhaul components at a cell site to enhance the user experience with respect to call setup times and latency. The present teachings also disclose flexibility to efficiently route voice and data traffic to different locations or geographic regions (e.g., different countries) to minimize costs to operators as well as end users.

This Summary is provided to introduce a selection of concepts in a simplified form that is further described below.

Accordingly, in one aspect of the present invention, there is provided a cellular system as set out in the first of the appending independent claims. In another aspect of the present invention, there is provided a method as set out in the second of the appending independent claims. Features of various embodiments are set out in the appending dependent claims.

There is also disclosed herein examples of a cellular system to provide voice and data services to a user terminal. The cellular system includes a cellular base station; a satellite backhaul including a first satellite link and a second satellite link; and a traffic classifier to classify traffic from the cellular base station as voice traffic for transportation via the first satellite link and as data traffic for transportation via the second satellite link.

There is also disclosed herein examples of a method for providing voice and data services to a user terminal of a cellular system. The method includes: providing a cellular base station; providing a satellite backhaul including a first satellite link and a second satellite link; classifying traffic from the cellular base station as voice traffic or data traffic; and transporting the voice traffic via the first satellite link and the data traffic via the second satellite link.

Additional features will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of what is described.

In order to describe the manner in which the above-recited and other advantages and features may be obtained, a more particular description is provided below and will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments, implementations will be described and explained with additional specificity and detail through the use of the accompanying drawings.

The present teachings disclose a satellite backhaul that provides the flexibility to carry the LTE traffic from a user terminal (UT) to different geographic locations or countries based on the traffic type, wherein voice traffic is routed locally within the country to avoid long distance or international billing charge and data traffic is routed to a foreign country that already has the Internet infrastructure.

Embodiments are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the scope of the appending claims.

The terminology used herein is for describing particular embodiments only and is not intended to be limiting of the present disclosure. Furthermore, the use of the terms a, an, etc. does not denote a limitation of quantity but rather denotes the presence of at least one of the referenced item. The use of the terms "first," "second," and the like does not imply any particular order, but they are included to either identify individual elements or to distinguish one element from another. It will be further understood that the terms "comprises" and/or "comprising", or "includes" and/or "including" when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. Although some features may be described with respect to individual exemplary embodiments, aspects need not be limited thereto such that features from one or more exemplary embodiments may be combinable with other features from one or more exemplary embodiments.

The present teachings disclose a satellite backhaul that provides the flexibility to carry user traffic from a user terminal (UT) over a cellular system, such as, a Long-Term Evolution (LTE) network, to different geographic regions based on the traffic type. Voice traffic is routed locally within a first region to avoid a long distance or international billing charge and data traffic is routed to a second region different than the first region. The second region may have a more robust Internet infrastructure or maybe closer to data centers providing services over the internet. In exemplary embodiments, a region may be a country, a state or province, a legal jurisdiction or the like.

The present teachings allow cellular traffic, for example, from an LTE Evolved Node B (eNB) site, to be routed to different regions with the voice going to one region and data going to another. In exemplary embodiments, a cell-site may be located in a geographic region having only a basic telephone network infrastructure with limited or no internet network connectivity. In such a case, voice traffic from the cell site is routed to a local, in-country, telephone network while data traffic is routed to a location out-of-country that has a mature internet infrastructure.

The present teachings disclose integration of cellular and satellite backhaul components at a cell site to enhance the user experience with respect to call setup times and latency. The present teachings also disclose local switching of voice calls, for example, at an LTE cell site. The present teachings also disclose flexibility to efficiently route voice and data traffic to different locations or geographic regions (e.g., different countries) to minimize costs to operators as well as end users.

In various embodiments, the present teachings disclose multiple integration options including, without limitation:.

In certain conditions, it is very difficult to connect a cellular network base station or Enhanced Node B (eNB), for example, an LTE eNB, to its Core Network (CN). The difficult conditions may include a distance to the core network, right-of-way to the core network, the terrestrial landscape or the like. For difficult conditions, a satellite backhaul is a viable solution to carry traffic between eNB and the CN.

Satellite communication network for LTE backhaul includes a VSAT and a VSAT Gateway (GW) where the eNB is connected to the VSAT and the CN is connected to the VSAT GW.

The present teachings disclose multiple network designs where the traffic from an eNB is routed to two different geographic regions, locations or countries based on the traffic type. Similarly, traffic from two different geographic locations or countries is routed to an eNB based on the traffic type.

The procedures and messages described here are based on well-known and widely deployed 3GPP standard. As such, the present teachings reference the standards and do not disclose special signaling such as signaling for Specific IP Traffic Offload (SIPTO) or signaling for Local IP access (LIPA).

<FIG> illustrates a cellular system including a satellite backhaul that separately routes for voice traffic and data traffic over a satellite link according to various embodiments.

A cellular system <NUM> includes a satellite backhaul <NUM> to provide communication service to an eNB and any UTs being serviced by the eNB. The satellite backhaul <NUM> may include a VSAT <NUM> for communicating voice traffic with a VSAT GW B, and a VSAT <NUM> for communicating data traffic with a VSAT GW A. In exemplary embodiments, a UT is serviced by an Enhanced Node B (eNB) in region B. The UT generates UT traffic that may be split by classification. The voice traffic included in the UT traffic is sent to a PSTN of region B. By routing voice traffic within region B, long distance or international voice call charges are minimized for an end user of the UT. In contrast, data traffic included in the UT traffic is sent to region A that is a different geographic region from region B. Routing of data traffic to region A enhances an experience for the end user of the UT by decreasing latency or the like. The enhanced user experience for data services is because region A has a better Internet infrastructure than region B.

In the present invention, region A is in a first country and region B is in a second country different from the first country. In examples beyond the scope of the appending claims, region B may be a rural location in a country while region A may be in the same country, but with a better Internet infrastructure than region B.

In exemplary embodiments, classification or splitting of the traffic is provided by a traffic classifier <NUM>, such as a PGW. As a traffic classifier <NUM>, the PGW may classify the traffic with a traffic type, such as a Differentiated Services Code Point (DSCP), or any other traffic characteristics to separate voice and data traffic. Traffic may be classified by other traffic characteristics, such as source address, destination address or traffic type and assigned to a specific traffic class. In EPC, the PGW provides connectivity from the UT to external packet data networks by being the point of exit and entry of traffic for the UT. The traffic classification is used to route voice and data traffic separately, for example, by a router (not shown). In some embodiments, network traffic through the router may be subjected to classification and conditioning.

The satellite backhaul <NUM> may include a VSAT, a VSAT GW and satellite links. In <FIG>, a satellite link for transporting data traffic is illustrated with a dashed line, and a satellite link for transporting voice traffic is illustrated with a solid line. In some embodiments, VSAT GW A, VSAT GW B, or both may be a VSAT. In some embodiments, VSAT <NUM>, VSAT <NUM>, or both may be a VSAT GW. In exemplary embodiments, VSAT <NUM> and VSAT <NUM> may utilize the same radio, the same antenna, the same demodulator, or the like, to send and receive at least two information streams with one stream for VSAT GW A and one stream for VSAT GW B.

In some embodiments, the cellular system of the present teachings utilizes a PGW disposed between the eNB, and VSAT <NUM> and VSAT <NUM> (see, for example, <FIG> or <FIG>). For brevity, this configuration is referred to as a "single PGW configuration" in the present teachings; nothing in the present teachings limits the number of PGWs in this configuration to only one or a single PGW. In some embodiments, the cellular system of the present teachings may not utilize a PGW disposed between the eNB, and VSAT <NUM> and VSAT <NUM> (see, for example, <FIG>). For brevity, this configuration is referred to as a "multiple PGW configuration" in the present teachings.

In a single PGW configuration, the PGW a UT is located locally in a region, i.e., region B. A traffic classifier, for example, included in the PGW, differentiates between voice and data traffic from the UT and includes a traffic type in the UT traffic to the router. A router uses the traffic type to route, for example, the data traffic to another region, for example, region A.

Billing for the UT is reported by the PGW to a central billing system of region B. In a Call Data Record (CDR) an itemized billing for the UT indicates billing information, for example, the traffic type such as voice or data, the source and destination IP addresses, and other specific characteristics relevant to the billing system to properly charge the voice and data usage. In exemplary embodiments, the router may route based on an IP destination address.

For the single PGW configuration, there are two options on how to dispose of the EPC components: co-located and split EPC components.

<FIG> illustrates a cellular system including a satellite backhaul and a PDN (Packet Data Network) Gateway (PGW) co-located with Evolved Packet Core (EPC) components according to various embodiments.

A cellular system <NUM> includes a satellite backhaul <NUM> to provide communication service to an eNB and any UTs being serviced by the eNB. The satellite backhaul <NUM> may include a VSAT <NUM> for communicating voice traffic with a VSAT GW B, and a VSAT <NUM> for communicating data traffic with a VSAT GW A. In the cellular system <NUM> the voice and data are split with a single PGW configuration. For this configuration, the eNB, MME, SGW, PGW <NUM>, and PCRF are located in region B. In exemplary embodiments, the eNB, MME, SGW, PGW <NUM>, and PCRF are located close to one another. In exemplary embodiments, the associated HSS B <NUM> and IMS are centralized inside region B, although not necessarily close to the eNB. In the exemplary embodiment of <FIG>, region B has two eNBs (eNB1 and eNB2), each associated with an EPC CN (MME, SGW, PGW) and a PCRF. However, the HSS B <NUM> and IMS are common for all UTs in Region B. The satellite backhaul <NUM> includes satellite links. In <FIG>, a satellite link for transporting data traffic is illustrated with a dashed line, and a satellite link for transporting voice traffic is illustrated with a solid line.

The PGW <NUM> associated with eNB1 is connected to two VSATs (VSAT <NUM> and VSAT <NUM>) through a router <NUM>. The PGW associated with eNB2 is connected to two VSATs through a router. In exemplary embodiments, the SGW interfaces to the PGW <NUM> via an S5 interface. A traffic classifier included in the PGW differentiates between voice and data traffic from the UT and includes a traffic type in the UT traffic to the router <NUM>.

The router <NUM> inspects and routes the traffic to the appropriate VSAT depending on the traffic type. As illustrated in <FIG>, voice traffic is routed to the VSAT <NUM> communicating with VSAT GW B. Generally, VSAT <NUM> and VSAT GW B are disposed in the same region, i.e., region B. Data traffic is routed to the VSAT <NUM> communicating with VSAT GW A. Generally, VSAT <NUM> and VSAT GW A are disposed in the different regions, i.e., region B and region A respectively. In exemplary embodiments, the router determines the traffic type based on a destination IP address, a DSCP, or any other characteristic to distinguish voice from data traffic. In exemplary embodiments, information transfer between the SGW/PGWs disposed in region B may be communicated via terrestrial communications. In exemplary embodiments, information and signaling necessary to provide voice services to the UT may be typed as "voice traffic. " For example, the IMS and HSS information and signaling may be classified as voice traffic and thus be routed to VSAT GW B by the router. In exemplary embodiments, information and signaling necessary to provide data services, such as the Internet, to the UT may be typed as "data traffic.

<FIG> illustrates a registration flow for a User Terminal (UT) for a cellular system of <FIG> according to various embodiments.

An advantage of the cellular system <NUM> of <FIG> is reduced latency as the UT signaling need not go over the satellite backhaul <NUM>. Exemplary UT signaling may include attach or release, dedicated bearer setup, and other signaling. In exemplary embodiments, a centralized component of the cellular system <NUM> of <FIG> is the HSS B storing the profiles for all UTs in region B.

A flow <NUM> of servicing a UT includes the following operations. Every UT in region B attaches at operation <NUM> to the EPC also in region B. During the attach operation <NUM>, an MME B consults the HSS B (<FIG>, <NUM>) to get the UT subscription profile. The default and dedicated bearers for the UT are defined in a co-located PCRF B that pushes the information to the PGW (<FIG>, <NUM>). Every UT in region B has its traffic (voice and data) go through a single SGW and PGW pairing. In other words, every UT is only assigned a single Access Point Name (APN) managed by the single PGW.

After the UT attaches to the EPC network, the UT registers at operation <NUM> to the IMS in region B. In exemplary embodiments, the registration at operation <NUM> may be a Session Initiation Protocol (SIP) Registration. After registering, the UT can start Voice over LTE (VoLTE) session or receive VoLTE incoming call. For a UT to UT voice call, the voice traffic between UTs is routed locally by the PGW and the voice traffic for a call between a UT serviced by the eNB1 to a UT serviced by the eNB2 does not go over the satellite backhaul (<FIG>, <NUM>). Hence, the latency for such a UT to UT voice call is low.

In this example, the traffic classifier in the PGW (<FIG>, <NUM>) splits the UT traffic, and the router (<FIG>, <NUM>) inspects the traffic and separately routes, at operation <NUM>) the data traffic to VSAT <NUM> at operation <NUM> and voice traffic to VSAT <NUM> at operation <NUM>. Signaling between the MME and the HSS, and between the UTs and the IMS are routed to VSAT <NUM> since the HSS and the IMS are located inside region B.

<FIG> illustrates a flow for paging a UT for incoming data of <FIG> for a cellular system according to various embodiments.

A flow <NUM> of servicing a UT includes the following operations. For incoming data traffic, as the data for a UT is coming from VSAT GW A (<FIG>, VSAT GW A is in region A), VSAT GW A communicates with the VSAT (VSAT <NUM>) that can route the incoming data to the UT. In some embodiments, the VSAT GW A maps a pool of IP addresses to a particular PGW and directs the particular PGW to assign an IP address to a UT from the pool of IP addresses at operation <NUM>. Thus, the VSAT GW A maps a destination UT IP address to communicate the incoming data to the associated PGW. In cellular systems, paging at operation <NUM> is sent by the MME if there is incoming traffic destined for a UT in Idle Mode.

<FIG> illustrates a flow for paging a UT for incoming voice call for a cellular system of <FIG> according to various embodiments.

A flow <NUM> of servicing a UT includes the following operations. For an incoming voice call, the IMS knows the location of the UT from the HSS at operation <NUM>. IMS forwards the SIP INVITE to the VSAT GW B which in turns sends the SIP INVITE to the PGW at operation <NUM>. The VSAT GW B determines the location of the UT at operation <NUM>. In some embodiments, the VSAT GW B maps a pool of IP addresses to a particular PGW and the VSAT configured to communicate with the PGW. In some embodiments, the UT IP address is assigned by the PGW. Thus, the destination UT IP address may be used by the VSAT GW B to determine which VSAT should receive the incoming voice data to process the SIP Invite request. At operation <NUM>, a response to the SIP Invite may be provided by the UT.

When the PGW (<FIG>, <NUM>) receives downlink (DL) data for a UT, either for data traffic or for voice SIP signaling, PGW will look at the state of the UT. If PGW does not have any information about that UT, PGW sends a notification to MME indicating that there is DL data for that UT. MME then starts the Paging process of <FIG>.

As seen from <FIG> and <FIG>, since the MME is located in the VSAT site, there are only a few paging steps that need to go over the satellite backhaul (<FIG>, <NUM>). For Paging for Voice signaling as shown in <FIG>, there are few more signaling steps that go over the satellite backhaul for a voice call as another dedicated bearer needs to be created for carrying the voice media traffic.

<FIG> illustrates a flow for a handover of a UT for a cellular system of <FIG> according to various embodiments.

<FIG> illustrates the handover (HO) flow <NUM>. <FIG> is based on an S1 handover where the signaling messages from target to source or vice versa are carried on the S1 interface. In some embodiments, the transfer of eNB data is carried on X1 interface. X1 interface is an interface between eNBs. The HO procedure illustrated in <FIG> is also for a condition where there is no direct terrestrial link between the source and target eNBs. Since all EPC components are located at the eNB site, only a few signaling steps between source and target go through the satellite backhaul. At operation <NUM> a source eNB transmits an HO request to relocate a UT to a target eNB to a target MME. The relocation request traverses the satellite backhaul. At operation <NUM>, the target MME creates an indirect data forwarding tunnel to the target eNB. At operation <NUM>, the UT is detached from the source eNB to the target eNB. The UT contexts at the source PGW can also be transferred to the target PGW so that UT session will still be active during and after HO.

<FIG> illustrates a cellular system including a satellite backhaul and a PGW with EPC components split across the satellite backhaul according to various embodiments.

A cellular system <NUM> may include a satellite backhaul <NUM> to provide communication service to an eNB and any UTs being serviced by the eNB using a single PGW <NUM>. For the cellular system <NUM>, an SGW and PGW <NUM> pair are located near the eNB. The MME, PCRF, HSS and the IMS components are centralized inside the region and are common for all UTs in region B. The PGW connects to two VSATs (VSAT1 and VSAT2) through a router <NUM>. The SGW interfaces to the PGW <NUM> via the S5 interface. The satellite backhaul <NUM> may include satellite links. In <FIG>, a satellite link for transporting data traffic is illustrated with a dashed line, and a satellite link for transporting voice traffic is illustrated with a solid line.

The PGW <NUM> associates a traffic type with the traffic from a UT, the router <NUM> inspects the traffic type and routes the associated traffic to the appropriate VSAT depending on the traffic type. The voice traffic is routed to the VSAT1 that is communicating with VSAT GW B within a region or country B. Data traffic to the internet is routed to the VSAT2 that is communicating with VSAT GW A in a different country or region A.

The router <NUM> may inspect the traffic type based on destination IP address, DSCP, and any other distinct characteristic to distinguish voice and data traffic for proper routing. The following description is applicable for a UT in Country B. Network traffic through the router <NUM> may be subjected to classification and conditioning. Traffic may be classified by many different parameters, such as source address, destination address or traffic type and assigned to a specific traffic class. Traffic in each class may be further conditioned by subjecting the traffic to rate limiters, traffic policers or shapers.

<FIG> illustrates a registration flow for a UT for a cellular system of <FIG> according to various embodiments.

A UT in country B attaches to the EPC in country B. During the attach process, per operation <NUM>, MME B consults the HSS B to get the UT subscription profile. The default and dedicated bearers for the UT are defined in PCRF B and the PCRF B then pushes, per operation <NUM>, the bearers to PGW <NUM> of <FIG>. The UT in country B has its voice and data traffic go through one SGW and one PGW <NUM>. In other words, every UT is only assigned a single APN.

After the UT attaches to the EPC network, the UT may register with the IMS in Country B per operation <NUM> using, for example, a SIP registration. After the registration per operation <NUM>, the UT may start a Voice over LTE (VoLTE) session or receive a VoLTE incoming call per operation <NUM>.

In exemplary embodiments, the router <NUM> inspects the traffic per operation <NUM> and routes the data traffic to VSAT <NUM> per operation <NUM> and voice traffic to VSAT <NUM> per operation <NUM>. Signaling between MME and HSS and between UT and IMS are routed to VSAT <NUM> since HSS and IMS are located inside the country B.

<FIG> illustrates a flow for paging a UT for incoming data for a cellular system of <FIG> according to various embodiments.

A flow <NUM> of servicing a UT includes the following operations. Paging is sent by an MME if there is incoming data traffic destined for a UT in Idle Mode. For incoming data traffic, since the data for a UT is coming from VSAT GW A (VSAT GW A is in country A), VSAT GW A needs to determine the VSAT (VSAT <NUM>) that can route the incoming data to the UT. In some embodiments, the VSAT GW A maps a pool of IP addresses to a particular PGW and directs the PGW to assign an IP address to a UT from the pool of IP addresses assigned to the PGW at operation <NUM>. Thus, the VSAT GW A maps a destination UT IP address to communicate the incoming data to the associated PGW. In cellular systems, paging at operation <NUM> is sent by the MME if there is incoming traffic destined for a UT in Idle Mode.

A flow <NUM> of servicing a UT includes the following operations. For an incoming voice call, the IMS knows the location of the UT from the HSS at operation <NUM>. The IMS forwards the SIP INVITE to the VSAT GW B which in turns sends the SIP INVITE to the PGW at operation <NUM>. The VSAT GW B determines the location of the UT at operation <NUM>. In some embodiments, the VSAT GW B maps a pool of IP addresses to a particular PGW and the VSAT configured to communicate with the PGW. In some embodiments, the UT IP address is assigned by the PGW. Thus, the destination UT IP address may be used by the VSAT GW B to determine which VSAT should receive the incoming voice data to process the SIP Invite request. At operation <NUM>, a response to the SIP Invite may be provided by the UT.

When PGW receives DL data for a UT, either for data traffic or for voice SIP signaling, PGW will look at the state of the UT. If PGW does not have any information about that UT, PGW sends a notification to MME indicating that there is DL data for that UT. MME then starts the Paging process of <FIG>.

As seen from <FIG> and <FIG>, since the MME is located in the VSAT GW site, there are many Paging steps that need to go over the satellite backhaul. For Paging for voice signaling as shown in <FIG>, there are few more signaling steps that go over the satellite since, for a voice call, another dedicated bearer needs to be created for carrying the voice media traffic.

<FIG> illustrates the HO flow <NUM>. <FIG> is based on an S1 handover where the signaling messages from target to source or vice versa are carried on the S1 interface. In some embodiments, the transfer of eNB data is carried on X1 interface. X1 interface is an interface between eNBs. The HO procedure of <FIG> also depicts a flow for when there is no direct terrestrial link between the source and target eNBs. The UT contexts at the source PGW can also be transferred to the target PGW so that UT session will still be active during and after HO.

Since the MME is reachable over a satellite backhaul by the eNB via the VSAT GW B (MME B), the MME B may handle all UTs in country B. Thus, an HO in the cellular network of <FIG> may have an MME change. This simplifies the HO procedure. However, since the SGW and PGW are located at the eNB site, many of the HO signaling steps have to go via the satellite.

<FIG> illustrates a cellular system including a satellite backhaul and multiple PGWs according to various embodiments.

A cellular system <NUM> may include a satellite backhaul <NUM> (or a Satellite Backhaul Network) with multiple PGWs <NUM>, <NUM>. For the cellular system <NUM>, country A and B may have an EPC CN including an MME, an SGW, and a PGW. Country A and B may also components such as a PCRF, an HSS, and an IMS.

In <FIG>, Country B there are two eNBs (eNB1 and eNB2), one EPC and one IMS. In country B the SGW <NUM> may connect to two VSATs (VSAT <NUM> and VSAT <NUM>). Country A may have a remote PGW <NUM> in country A (remote from country B) to route data from country B to the internet. Country B may have a local PGW <NUM> in country B (local to country B) to route voice calls from the IMS to the UT.

For the cellular system <NUM>, a UT may be assigned two IP addresses corresponding to the two PGWs <NUM> and <NUM>. As such, each UT may be provided two APNs, one per PGW. A first IP address is assigned by the PGW <NUM> local to country B, and one IP address is assigned to UT of country B by the remote PGW <NUM> (remote PGW can be in a different country such as country A). in exemplary embodiments, the local PGW <NUM> is located in between the VSAT GW B and a MGW in country B. In some embodiments, the local PGW <NUM> is located in between the SGW <NUM> and VSAT <NUM> (not shown in <FIG>) in country B.

Data traffic from UT in country B is routed to the remote PGW <NUM> in Country A using a satellite backhaul <NUM>. The satellite backhaul <NUM> may include satellite links. In <FIG>, a satellite link for transporting data traffic is illustrated with a dashed line, and a satellite link for transporting voice traffic is illustrated with a solid line. Every SGW <NUM> in Country B may have S5 and S8 interfaces simultaneously for each UT. S5 is the interface between the SGW and the local PGW <NUM>. The PGW <NUM> may be in country B. In some embodiments, eNB1 may have to communicate with the local PGW <NUM> via the satellite backhaul <NUM>. The S8 is an interface between the local SGW <NUM> and the remote PGW <NUM>. The remote PGW <NUM> may be disposed in a different country, i.e., the S8 is an interface between the SGW <NUM> in the Country B and the PGW <NUM> in Country A.

<FIG> illustrates UT registration for a cellular system of <FIG> according to various embodiments.

During the attach process (see <FIG>) the MME B consults the HSS B to get the UT subscription profile. The UT in its profile includes two default APNs, i.e. two PGWs, one is in Country B and the other one is in Country A.

In some embodiments, when the UT sends an Attach message, the UT includes two APNs, i.e., two PGWs, one in Country B and another one in Country A. In this case, the UT profile in the HSS does not need to be specified with default APNs.

During the Attach process, the SGW sends a Create Session request to the local and remote PGWs. For connection with the local PGW, the default and dedicated bearers for the UT for voice traffic may be defined in the PCRF B which then pushes it to the local PGW. An S5 interface is established between SGW and local PGW.

When connecting with the remote PGW, the remote PGW receives a Create Session request from the SGW and the PGW gets the UT profile from the PCRF B because the UT profile is defined in PCRF B. The PGW may create the default and dedicated bearers for the UT for data traffic. The PCRF B then pushes the UT profile to the remote PGW. An S8 interface is established between the SGW and the remote PGW.

In some embodiments, UTs in country B might also have their profiles defined in a PCRF in country A so that the remote PGW does not need to contact the local PCRF B. This solution might put a burden on the PCRF in country A as many UTs in different countries might need to have their profiles stored in the PCRF in country A.

After the UT attaches to the EPC network, the UT registers to the IMS in Country B so that the UT can start a Voice over LTE (VoLTE) session or receive a VoLTE incoming call.

The SGW determines the traffic type from a UT. For data traffic, The SGW routes the UT traffic to PGW in Country A through the VSAT2 in country B as it is communicating with VSAT GW A in Country A. VSAT GW A in Country A may forward this traffic to the PGW in Country A. For data traffic that comes from the Internet, the PGW in Country A inspects the UT destination IP address. The PGW then forwards the incoming data to the VSAT GW A that in turn transports the data to the UT in Country B.

For voice traffic, the SGW routes the UT traffic to the PGW in Country B through VSAT1 in country B that communicates with VSAT GW B in Country B. VSAT GW B in Country B may forward the voice traffic to the PGW in Country B which in turn forwards the voice traffic to the MGW in the same country.

<FIG> illustrates a flowchart of an exemplary method for providing voice and data services to a user terminal of a cellular system according to various embodiments.

The present teachings provide a method <NUM> for providing voice and data services to a user terminal of a cellular system. The method <NUM> provides for communicating voice traffic separate from data traffic when using a satellite backhaul with a cellular base station.

In exemplary embodiments, the method <NUM> includes operation <NUM> to provide a satellite data gateway outside a region where a cellular base station is deployed. The method <NUM> may include operation <NUM> to provide a satellite voice gateway inside the region where the cellular base station is deployed. The method <NUM> may include operation <NUM> to provision a PGW with IP addresses for group A and group B. The method <NUM> may include operation <NUM> to map group A of IP addresses to a VSAT at the satellite data gateway. The method <NUM> may include operation <NUM> to map group B of IP addresses to VSAT at the satellite voice gateway.

In exemplary embodiments, the method <NUM> includes operation <NUM> to provision a UT on cellular network. The method <NUM> may include operation <NUM> to allocate an IP address to a UT from group A. The method <NUM> may include operation <NUM> to allocate an IP address to the UT from group B during attach. The method <NUM> may include operation <NUM> to attach the UT with a voice service provider using the allocated group B IP address. The method <NUM> may include operation <NUM> to register the UT with the voice service provider using the allocated group B IP address.

In exemplary embodiments, the method <NUM> includes operation <NUM> to communicate traffic originating at the UT. The method <NUM> may include operation <NUM> to classify the UT traffic as voice or data. The method <NUM> may include operation <NUM> to communicate the UT voice traffic to the satellite voice gateway. The method <NUM> may include operation <NUM> to communicate the data traffic to the satellite data gateway.

In exemplary embodiments, the method <NUM> includes operation <NUM> to communicate from the satellite data gateway to the UT. The method <NUM> may include operation <NUM> to determine the VSAT by the destination address of the UT in the incoming packet. The method <NUM> may include operation <NUM> to communicate with the determined VSAT to send data to the UT.

In exemplary embodiments, the method <NUM> includes operation <NUM> to communicate from the satellite voice gateway to the UT. The method <NUM> may include operation <NUM> to determine the VSAT by its address in registration. The method <NUM> may include operation <NUM> to communicate with the determined VSAT to send voice traffic to the UT.

Claim 1:
A cellular system (<NUM>) to provide voice and data services to a user terminal, the cellular system comprising:
a cellular base station; and
a satellite backhaul (<NUM>, <NUM>, <NUM>, <NUM>) comprising a first satellite link and a second satellite link;
whereby the cellular system further comprises a traffic classifier (<NUM>), connected to and co-located with the cellular base station, to classify traffic from the cellular base station as voice traffic for transportation via the first satellite link to a satellite voice gateway and as data traffic for transportation via the second satellite link to a satellite data gateway;
the cellular system being characterized in that
the voice traffic is communicated within a first region by the first satellite link and the data traffic is communicated to a second region different from the first region by the second satellite link;
the cellular system comprises an Evolved Packet Core Core Network comprising a Serving Gateway, a Packet Data Network Gateway (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), a Mobility Management Entity, a PCRF, and a Home Subscriber Server; and
the cellular base station communicates with an IP Multimedia Subsystem via the first satellite link and an Internet Gateway over the second satellite link.