The present invention relates to satellite communications. More particularly, and not by way of limitation, the present invention is directed to a system and method for facilitating mobile satellite service via a Third Generation Partnership Project (3GPP) generic radio access network. As used herein, the abbreviations used herein shall have the following meanings:
AAA Authentication, Authorization and Accounting
AP Access Point
ATC Ancillary Terrestrial Component
BER Bit Error Rate
BSC Base Station Controller
BTS Base Transceiver Station
CC Call Control
CS Circuit Switched
EGPRS Enhanced General Packet Radio Service
FCC Federal Communications Commission
GAN Generic Access Network
GANC Generic Access Network Controller
GMR Geo Mobile Radio
GMR 3G Geo Mobile Radio with 3G (evolution of GMR1 or GMR2 protocols to support packet access support)
Gb Interface between BSC and SGSN
GPRS General Packet Radio Service
GSM Global System for Mobile Communication
HBS Home Base Station
HBSC Home Base Station Controller
HLR Home Location Register
HSPA High Speed Packet Access
IGW IP Gateway
IP Internet Protocol
IETF Internet Engineering Task Force
LTE Long Term Evolution
MAC Medium Access Control
MIPv6 Mobile IP version 6
MM Mobility Management
MME Mobility Management Entity
MMS Multimedia Messaging Services
MS Mobile Station
MSS Mobile Satellite Service
PCU Packet Channel Unit
RLC Radio Link Control
RFC Request for Comments
RTP Real Time Protocol
SAE System Architecture Evolution
SGSN Serving GPRS Support Node
SGW Security Gateway
SMS Short Messaging Services
UT User Terminal
UMA Unlicensed Mobile Access
WCDMA Wideband Code Division Multiple Access
XCP Explicit Control Protocol
The US Federal Communications Commission (FCC) permits MSS spectrum to be used nationwide on the ground for terrestrial networks (under the ATC), provided that Satellite services are also offered. MSS operators are thus able to offer terrestrial mobile telecommunication services using a hybrid satellite/terrestrial UT.
In order to be successful, MSS/ATC operators must be able to leverage the economies of scale of the existing UTs and also the existing mobile communication network infrastructure. While it is possible to implement a system using ETSI GMR1 or GMR2 standards, as derivative of mainstream 3GPP GSM/EGPRS standards, it will likely be cost prohibitive to sustain the satellite component in an integrated UT or mobile communication infrastructure when terrestrial standards continue evolve to later generations.
The 3GPP GAN enables end users to use alternative air interface technologies, such as Bluetooth and WiFi, to access mobile services that otherwise are commonly accessed using WCDMA/GSM/EGPRS networks. One system that illustrates the 3GPP GAN reference architecture is Ericsson's Mobile@Home system as seen in
Conventional MSS systems are based on several air interface standards, including: GMR1, GMR2, Globalstar air interface, Iridium air interface and Inmarsat 14 air interface. Each of these standards is unique, and hence they are non-interoperable. As a result, the MSS is fragmented, making it difficult to leverage economies of scale in the MSS market for UT and the network infrastructure. As a result, the MSS has seen limited market success.
It would thus be advantageous to have a system and method for simpler reference network architecture to support a satellite component as generic access in the terrestrial mobile networks and UTs that overcomes the disadvantages of the prior art. The present invention provides such a system and method.
The present invention comprises a system and method for simpler reference network architecture to support a satellite component as generic access in the terrestrial mobile networks. The present invention uses the 3GPP baseline standard, 3GPP GAN, to support a MSS satellite component at the physical, RLC and MAC layers, with the terrestrial standards based in the Generic Access Protocol architecture framework. The present invention seamlessly incorporates satellite component lower layers into the GAN protocol architecture, leveraging the flexibility of the IP transport protocols between the UT or MS and the GAN Radio Access Network to slide in satellite protocol lower layers in the GAN protocol architecture framework. To support this mobility management system across the IP domain, the present invention uses the IETF RFC 4423 protocol for Host Identity protocol and multi-homing support. These additions are transparent to the GAN infrastructure, particularly the UMA GANC.
In the following section, the invention will be described with reference to exemplary embodiments illustrated in the Figures, in which:
In the present invention, the 3GPP GAN protocol stack is used to provide access by satellite instead of by Bluetooth or WiFi. This enables the MSS component to be incorporated into the existing terrestrial UT or MS and network that supports the 3GPP GAN reference architecture. This is seen in
Referring now to the satellite protocol lower layers, the present invention provides that the satellite protocol architecture in the 3GPP GAN framework will be comprised of the physical, RLC, MAC and IP transport layers. These will comprise peer to peer protocol layers between the UT or MS and a satellite RBS. The satellite physical, RLC and MAC layers comprise an adaptation of the terrestrial EGPRS standards for physical, RLC and MAC layers. The adaptation of the physical, RLC and MAC layers are based on the Ericsson satellite cellular backhaul solutions for Abis over satellite.
Adapting the EGPRS satellite variants for the physical, RLC and MAC layers enables the reuse of the UT or MS EGPRS baseband and radio frequency electronics with minimal modification. Alternatively, the satellite physical, RLC, MAC layers can be based on proprietary VSAT IP modems technologies.
In one embodiment of the present invention, the satellite link can be optimized for voice calls using a low data rate codec over the GAN user plane without IP overhead. The encapsulation of the codec payload into IP packets with RTP headers can be performed in the satellite BTS as transparent connectivity to the BSC, either the Home BSC or GAN.
The satellite IP transport layer is an important aspect of the satellite RBS protocol stack of the present invention. The satellite IP transport layer contains performance enhancing proxies to combat satellite latencies and also provide a mechanism to appropriately map user locations, Identities to IP addresses and carrier frequencies in the lower layers for UT or MS mobility.
Mobility refers to the ability of the network to provide support for handover to mobile devices such as UTs and MSs as they change point of access. Device mobility can either be addressed at layer 3 of the protocol stack, which means that the IP forwarding mechanism, which is based on IP addresses with implicit location information, either needs to be changed or the addressing scheme has be modified. In this way, mobility is hidden from higher layer protocols, and the host's IP address remains unchanged.
This present invention is adapted to use the IETF RFC 4423, Host Identity Protocol, as an MME to implicitly map the end users locations for example to spot beam id and/or GPS positions and/or identities that are operable to determine end user locations. Alternatively MIPv6 can be used for mobility management to achieve similar results.
The IP stack could also optionally support multi homing (using TCP or SCTP protocol) for the user to enable mobility management to ensure device mobility of the UTs or MSs.
Several methods can be employed in concert with the present invention to determine the physical location of the UT or MS. These methods use information configured in the GAN and information received from the UT during location update typically via a GPS location. It is conventionally known that GANC is operable to allow an external database to map this data to the exact geographical location of the end user in relation to the spot beam id and/or GPS position. The UT or MS can also be adapted to report the geographic location to the GANC.
There are several known techniques to improve transmission efficiency in the presence of long propagation delay. The present invention can be adapted to use such known techniques such as those available via commonly known TCP/IP accelerator products such as performance enhancing proxies and/or using XCP. In this manner, the present invention leverages the principles of 3GPP GAN network, is based on open standard interfaces, such as Up protocol stack, IP transport layers, and IETF RFC 4423 concerning Host Identity Protocol and uses conventional performance enhancing techniques to combat long propagation delay. In this manner, a BSC, either a Home BSC or GANC, can be used with minimum modifications or no changes.
As seen in
As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a wide range of applications. Accordingly, the scope of patented subject matter should not be limited to any of the specific exemplary teachings discussed above, but is instead defined by the following claims.