FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION
“A method for providing QoS based IP services via satellite communication”

APPLICANTS:

Name Nationality Address
Devas Multimedia Private Limited
Indian Prema Gardenia, 357/6, 1st Cross, I Block, Jayanagar, Bangalore 560 011

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-
FIELD OF INVENTION
[001] This invention relates to satellite communications, and more particularly to managing multiple services offered over satellite communications.

BACKGROUND OF INVENTION
[002] Satellite communication networks were primarily designed to support voice traffic with a fixed bit rate. However, the satellite network may currently be used for a variety of services including video conferencing, asset tracking, on-demand messaging, telemetry and SCADA applications. As compared to voice traffic, which has a fixed bit rate, these services are of low volume, low duty factor, geographically dispersed, generally packetized, delay tolerant, busty in nature with variable bit rates and differing Quality of Service (QoS) requirements. Some of these services may also use unattended reporting terminals. Some of these services may have to be provisioned in short notice during emergencies. For such services, the satellite may not be optimally utilized under dynamic traffic conditions involving a large number of satellite terminals. Further, such services provide larger throughput permanent connectivity but do not employ QoS handling techniques to satisfy the QoS requirements for every service. Terrestrial mobile services have devised methods for handling such varying QoS demands. However, these have not been implemented in existing satellite communication systems.
[003] Multiple access schemes have been suggested for making satellite resources available to multiple users. The multiple access schemes could be connection oriented or contention oriented. In connection oriented multiple access schemes, the satellite resource is made available to a single terminal exclusively. Examples of connection oriented multiple access schemes are Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA) and so on. However, in such cases, the resource might be idle for periods of time if the terminal is not performing communications. In contention oriented multiple access schemes, the satellite resource is made available to multiple terminals on a suitable random access framework.
[004] Existing satellite communication mechanisms allow allocation of resources using schemes such as a Single Channel per Carrier (SCPC) or a Multiple Channel per Carrier (MCPC). In SCPC, a single terminal has access on that channel, while in MCPC, multiple users are sharing the channel. However, these mechanisms do not allow co-existence of both types of allocations schemes. There may be instances where the satellite resources could be employed for allocation of channels for both SCPC and MCPC but as the existing systems fail to support co-existence of such schemes the performance of the scheme gets degraded. This is because existing systems do not have the provision to satisfy the difference in the QoS requirements for different schemes. As a result, it is possible that the QoS requirements for different services are not met. Also, these systems do not have the provision to service the QoS requirements of different network layers.
[005] Further, allocation of the satellite resources may be permanent (PAMA) or demand assigned (DAMA). In a PAMA scheme, the bandwidth will be used regardless of the channel being used or not. However, such schemes perform poorly when the throughput levels are high. In addition, these mechanisms do not meet the requirements of the users individually. As a result, the existing mechanisms do not allow a plurality of multiple access schemes to co-exist in a communication system.
[006] Due to the aforementioned reasons present day systems do not support the co-existence of multiple services scheme. Further, satellite based services have not been explored for satisfying the QoS requirements of different services.

OBJECT OF INVENTION
[007] The principal object of this invention is to facilitate co-existence of multiple internet protocol based services over satellite communications.
[008] Another object of the invention is to provide simultaneous access of different services that have variable QoS requirements.

STATEMENT OF INVENTION
[009] Accordingly the invention provides a system for providing Quality of Service (QoS) based Internet Protocol services over satellite communications. The system provided with means adapted for obtaining a service requests from plurality of user terminals, determining QoS requirements for the service request and sending an indication to a satellite for allocation of slots to the service request if the service request has a higher QoS requirement.
[0010] There is also provided a method for providing QoS based Internet Protocol services over satellite communications. The method comprises steps of obtaining a service request from at least one user terminal, determining the QoS requirements for the service request, sending an indication to a satellite for allocation of slots to the service request if the service request has a higher QoS requirement.
[0011] There is also provided a Network Management System (NMS) for providing QoS based Internet Protocol services over satellite communications. The system provided with means adapted for obtaining a service requests from plurality of user terminals, determining the QoS requirements for the service request, sending an indication to a satellite for allocation of slots to the service request if the service request has a higher QoS requirement.
[0012] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES
[0013] This invention is illustrated in the accompanying drawings, through out which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0014] FIG. 1 illustrates the satellite communication network serving plurality of user terminals, according to embodiments as disclosed herein;
[0015] FIG.2 depicts a hub that handles satellite communications, according to embodiments as disclosed herein;
[0016] FIG. 3 illustrates the Network Management System (NMS), according to embodiments as disclosed herein;
[0017] FIG. 4 depicts the architecture of the satellite communication network, according to embodiments as disclosed herein; and
[0018] FIG. 5 is a flow diagram depicting the NMS handling requests from the user terminals.

DETAILED DESCRIPTION OF INVENTION
[0019] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0020] The embodiments herein achieve co-existence of different IP based services over satellite communications by providing appropriate methods thereof. Referring now to the drawings, and more particularly to FIGS. 1 through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0021] The method disclosed herein facilitates co-existence of different IP based services over satellite communications. The method provides different IP services over the same space segment to a large number of simultaneous users with variable QoS demands by employing terrestrial techniques to the Mobile Satellite Services (MSS). The method takes into consideration that different IP based services employed by the user terminals have different QoS requirements and hence the method employs a QoS based prioritization framework for enhanced service assurance. The method employs a satellite hub that is provided with an intelligent NMS in order to identify the QoS requirements of ever user and thus service the users based on their QoS requirements. In addition, the method employs schemes to maximize the efficiency and utility of the services provided by the satellite. For this purpose, the IP streams are shared by users under special allocation schemes at different layers of the network. Further, the method also takes into account the nature of traffic patterns, difference in latency requirements, variable data rates and multiple QoS requirements of different user terminals.
[0022] FIG. 1 illustrates the satellite communication network serving plurality of user terminals, according to embodiments as disclosed herein. The satellite communication network is a star configured Time Division Multiple Access (TDMA) network, provided with a central satellite hub. The satellite communication network comprises of a satellite hub 101, satellite 102 and a plurality of user terminals 101. In addition to fixed resource allocation, the satellite communication network also facilitates dynamic allocation of resources based on demands from the user terminals. In addition, the satellite communication network comprises of an outbound carrier to which all the user terminals 103 lock on and a number of inbound carriers. Each of the inbound carriers is connected to multiple user terminals 103.
[0023] The satellite hub 101 houses a pool of modems, a Radio Frequency (RF) module, a Network Management System (NMS) and a baseband module. The NMS comprises the brain of the satellite hub 101 as it constitutes the intelligence within it. The NMS takes into account the QoS requirements of the IP services and services the user terminals accordingly. The modems correspond to various topologies and are configured to operate accordingly. The hub is equipped with an outbound carrier. The outbound carrier locks on to all the user terminals 103. The satellite hub 101 is also provided with a router and a routing table. The router fetches the unique IP address of the user terminal 103 that requests for the data and identifies the user terminal 103. On identification, the router routes the data to the user terminal 103 via the satellite. In addition, the satellite hub 101 is also provided with a demodulator to cater to various user terminals. The architecture of the satellite hub 101 is designed such that it can operate with different topologies such as Time Division Multiplexing (TDM)/ Single Channel per Carrier (SCPCA), polled TDMA and so on. Further, the satellite 102 allocates resources to the user terminals 103 in TDMA mode, polled TDMA mode and so on.
[0024] The satellite 102 obtains the data transmitted by the satellite hub 101 and broadcasts the data to the user terminals 103. The satellite 102 also allocates channels to the user terminals 103 in order to communicate their data. The data broadcasted from the satellite 102 may be to an individual user terminal 103 or may be to a plurality of user terminals 103. The data may be broadcast over SCPC links to individual user terminals 103 and over MCPC link to group of user terminals 103. The satellite 102 relays the forward link IP data stream through a BSS transponder and the return link IP data stream through a MSS return link transponder for rendering services over the geographically defined service areas.
[0025] The user terminals 103 are located remotely and access the data broadcasted by the satellite 101. Each user terminal 103 is provided a unique IP address to recognize the user terminal 103. The user terminals 103 may include individual user terminals or a plurality of user terminals that are sharing the data broadcasted. The individual user terminals 103 may access the data through the SCPC link where only a single user will have access to the channel. Group of user terminals 103 access the data over the common channel allocated to the user terminals 103 through the MCPC link.
[0026] In an embodiment, the system may also operate in polled TDMA schemes. Then the satellite hub 101 accesses the user terminals 103 for monitor and control information in a sequential manner. This allows one modem at the hub to monitor a number of terminals. Further, it is also possible to increase the modems in the hub in order to have flexibility.
[0027] FIG.2 depicts a hub that handles satellite communications, according to embodiments as disclosed herein. The satellite hub 101 handles user requests, monitors and controls the transmission of data to the user terminals 103. The satellite hub 101 comprises an RF module 201, a plurality of modems 202, baseband module 203 and NMS 204.
[0028] The RF module 201 handles all radio frequency transmissions within the satellite hub 101. When there is a request from the user terminal 103 for audio, video and other such content, the content is sent to the user terminal 103 over radio frequency by the RF module 201.
[0029] The modems 202 correspond to various topologies and they are configured to operate accordingly. The number of modems 202 will depend on the total number of user terminals 103 and the number of user terminals 103 in each topology. The modems 202 address the request from different user terminals 103. The modems 202 are provided with the functionality of demodulation and routing. For this purpose, the modem is provided with a router in order to route the broadcast content to the satellite 102. The router is provided with a routing table that stores the unique address allocated to the user terminal 103 in order to route the data to the appropriate user terminal 103.
[0030] The baseband module 203 is responsible for handling baseband frequencies during transmission. The baseband module 203 allocates channels to the user terminals 103 for carrying data of the user terminals 103; it may also allocate the channel to broadcast IP content to the user terminals 103.
[0031] The NMS 204 acts as the brain of the satellite hub 101. The entire decision making is done by the NMS 204. The NMS 204 works in integration with other modules of the satellite hub 101. The NMS 204 has a log of files to store any activity. The NMS 204 receives the requests for service from the user terminals 103 and addresses the request. The NMS 204 determines if the requested service has a higher QoS requirement. In case, the service has a high QoS requirement the NMS 204 immediately takes up the service. In case the QoS requirement for the service is lesser, then the service request may be queued up in the queue for addressing it later. In an example, if the request obtained is for video on demand service, the NMS 204 determines that video on demand has a higher QoS requirement and hence services the request immediately. On the other hand, if the request made is for messaging service, then the NMS 204 determines that messaging has a lesser QoS requirement as compared to video on demand and the NMS 204 queues the request for messaging in the queue. Since the NMS 204 uses a dedicated inbound these channels may be used for traffic anytime. Further, the NMS 203 performs packet classification, scheduling and prioritization functions. The information carried by the hub regarding the user terminals 103 will be displayed at the NMS console.
[0032] FIG. 3 illustrates the Network Management System (NMS), according to embodiments as disclosed herein. The NMS 204 is responsible for receiving requests from the user terminals 103 and addressing the request based on the priority of the QoS requirements of the service. The NMS 204 houses within it modules such as a management entity 301, a management database 302, a network configuration center 305, an IP service manager 304, and an IP service monitor 305.
[0033] The management entity 301 is responsible for managing request obtained from various user terminals 103 or individual devices that are connected to the NMS 204. The management entity 301 uses the network management protocol in order to communicate with the user terminals 301.
[0034] The management database 302 is responsible for storing the log of files. The log of files contains information of every action performed by the NMS 204. The management database 302 may also comprise of the queue that maintains the list of requests received from the user terminals 103. The requested are queued in the database 302 and fetched at the time the NMS 204 services the request.
[0035] The network configuration center 303 includes software upgrade and configuration file management features that provide software backup and upgrade for network devices and centralized management on configuration files. The network configuration center 303 improves scalability for the entire system.
[0036] The IP service manager 304 is responsible for deployment function for IP VPN gateways. The IP service manager 304 handles the IP based service request and services the user terminals 103.
[0037] The IP service monitor 305 is responsible for monitoring the performance of IP VPN gateways in order to address different IP service request to the user terminals 103.
[0038] FIG. 4 depicts the architecture of the satellite communication network, according to embodiments as disclosed herein. The satellite communications network employed for IP services comprises of an integrated application center 401, the internet 402, an ISP gateway 403, an integrated network operations center 404, the hub 101, a plurality of satellites 102 and plurality of user terminals 103.
[0039] The user terminal 103a, 103b and 103c may have different IP service requirements. The user terminals 103a, 103b and 103c send requests for respective IP services to the satellite hub 101. On receiving the request, the satellite hub 102 examines the request and determines the request that has the highest QoS requirement. In an example, if user terminal 103b has the highest QoS requirement for its service then the satellite hub 102 takes up the request for servicing and intimates the satellite 102 in order to allocate slots to the user terminal 103b. While the request from other user terminals such as 103a and 103c are queued and addressed later based on the priority of their QoS requirements. The satellite hub 101 contacts the integrated applications center 401 for the IP service requested by user terminal 103b.
[0040] The integrated applications center 401 stores within it IP based applications. The integrated applications center 401 on receiving the request from the satellite hub 101 determines the type of IP service requested and provides the IP content. For example, if the IP content requested is video then it may be sent over the internet 402 to the ISP gateway 403.
[0041] The internet 402 provides the means in order to fetch the IP based content from the integrated applications center 401 and sends the same to the ISP gateway 403.
[0042] The ISP gateway 403 acts as an interface for the user terminals 103 for providing IP based content to the user terminals 103. The ISP gateway 403 interfaces with the internet 402 to provide any IP based content requested from the user terminal 103 to the satellite hub 101.
[0043] The IP content fetched is then sent to the integrated network operations center 404. The integrated network operations center 404 manages the transmission of the IP content to the satellite hub 101. It is responsible for managing all the IP content that moves through and from the integrated applications center 401 and the satellite hub 101.
[0044] The IP content is then sent to the satellite hub 101 that determines the user terminal 103 and sends the IP content to the user terminal 103 through satellite 102. The satellite allocates slots for transmission of the content to the user terminal 103 and the content is sent.
[0045] FIG. 5 is a flow diagram depicting the NMS handling requests from the user terminals. When a user terminal 103 wants to perform communication it may send a request to the satellite hub 101 for allocation of the channel or slots for its communication. The request from the user terminal 103 is sent (501) to satellite hub 102. The request is received (502) by the satellite hub 102. On receiving the request, the request is directed (503) towards the NMS 204. The NMS 204 examines (504) the request and determines the type of the request. On knowing the request type the QoS requirements of the service may be obtained. For example, if the IP service is for video conference then the QoS requirements of the service is definitely more than services such as asset tracking, voice traffic and so on. The NMS 204 then makes (505) a check of the priority of the services. Priority of the service is determined based on the type of the service. If there is a request for a service that has higher priority than the received request then, the received request is queued (506). The order of the queue may be based on the order of priorities of individual services. On the other hand, if the request has the highest priority, then the request is serviced immediately. The NMS 204 then intimates the satellite hub 102 that further informs the satellite 101. The satellite 101 allocates (507) the freely available slots for the requested service. Later, the next request is considered for service from the queue based on the priority. This ensures that the QoS requirements of the individual services are satisfied. The various actions in method 500 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 5 may be omitted.
[0046] In an embodiment, the techniques disclosed herein employ special allocation schemes at various network layers to achieve the required QoS differentiation for the applications. Further, the NMS 204 is responsible for addressing the QoS requirements for different layers of the network. The QoS at the physical layer of the network may be improved by ensuring that the modems of the satellite are sufficiently powered so that the receive system is capable of decoding the bits correctly. In case of link layer, the QoS of the link layer is enhanced by ensuring that the rate of transmission to the hub is optimized. It is necessary to ensure that the length of the messages is appropriate to have high throughput and better QoS. If the length of the message is too short it results in poor utilization of the channel while too long messages would result in longer queuing delay at the transmitter end. Hence, the length of the messages is kept such that it is neither too short nor too long. This ensures required QoS is attained. For other layers of the network, such as the application layer and the like the scheme provides for fine tuning the buffer sizes on various routers and switches. For specific applications that require low latency the window sizes at the application layer are adjusted. This ensures that the QoS of the other network layers is also high.
[0047] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The network elements shown in Fig. 1 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.
[0048] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

WE CLAIM:-

1. A system for providing Quality of Service (QoS) based Internet Protocol services over satellite communications, said system provided with at least one means adapted for
obtaining a service requests from plurality of user terminals;
determining QoS requirements for said service request; and
sending an indication to a satellite for allocation of slots to said service request if said service request has a higher QoS requirement.

2. The system as in claim 1, wherein said system is further adapted for queuing said service request if said service request has a lower QoS requirement than a second service request.

3. The system as in claim 1, wherein said system is further adapted for determining the QoS of said service request from the type of IP content requested in said service request.

4. The system as in claim 1, wherein said system is further adapted for considering account nature of traffic pattern, difference in latency requirements, variable data rates and multiple QoS requirements for allocation of said slots to said user terminals.

5. A method for providing QoS based Internet Protocol services over satellite communications, said method comprising
obtaining a service request from at least one user terminal;
determining the QoS requirements for said service request;
sending an indication to a satellite for allocation of slots to said service request if said service request has a higher QoS requirement.

6. The method as in claim 5, wherein said method further queues said service request if said service request has a lower QoS requirement that a second service request.

7. The method as in claim 5, wherein said method further determines the QoS of said service request from the type of IP content requested in said service request.

8. The method as in claim 5, wherein said method further sends said indication for allocating said slots for said services that include video on demand, asset tracking, telemetry, SCADA, voice traffic, on demand messaging, video conferencing.

9. The method as in claim 5, wherein said method further considers account nature of traffic pattern, difference in latency requirements, variable data rates and multiple QoS requirements for allocation of said slots to said user terminals.

10. A Network Management System (NMS) for providing QoS based Internet Protocol services over satellite communications, said system provided with at least one means adapted for
obtaining a service requests from plurality of user terminals;
determining the QoS requirements for said service request;
sending an indication to a satellite for allocation of slots to said service request if said service request has a higher QoS requirement.

11. The NMS as in claim 10, wherein said NMS is further adapted for queuing said service request if said service request has a lower QoS requirement that a second service request.

12. The NMS as in claim 10, wherein said NMS is further adapted for determining the QoS of said service request from the type of IP content requested in said service request.

13. The NMS as in claim 10, wherein said NMS is further adapted for considering account nature of traffic pattern, difference in latency requirements, variable data rates and multiple QoS requirements for allocation of said slots to said user terminals.

Dated 18th May 2011

Dr. Kalyan Chakravarthy
Patent Agent

ABSTRACT
A method for providing QoS based IP services via satellite communication is disclosed. This invention relates to satellite communications, and more particularly to managing multiple services offered over satellite communications. Existing communication systems do not allow different multiple IP based services to co-exist among the communication networks. Further, the existing schemes do not take into consideration the QoS requirements of different services. As a result, the QoS of the services is not satisfactory. The method disclosed herein facilitates co-existence of different IP based services over satellite communications. The method provides different IP services over the same space segment to a large number of simultaneous users with variable QoS demands. The method takes into consideration that different IP based services employed by the user terminals have different QoS requirements and hence the method employs a QoS based prioritization framework for enhanced service assurance. FIG. 1