UPSTREAM RESOURCE OPTIMIZATION

• US 20080298299A1
• Filed: 07/17/2008
• Published: 12/04/2008
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Thesling, William H.
• Granted Patent: US 7,995,515 B2
• Time in Patent Office: Days
• US Class Current: 370/316
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access

Abstract

Systems, methods, and devices are described for scheduling and mapping upstream communications in a satellite communications system. The disclosure includes various channelization and frequency hopping techniques. A gateway is described to perform novel allocation of time slots on upstream frequency channels to allow frequency hopping. A subscriber terminal may perform frequency hopping according to the allocation, and the range may be limited to the transition range of a digitally controlled oscillator unit at the subscriber terminal. A gateway is described to allocate time slots on different upstream frequency channels in a prioritized manner. Subscriber terminals may receive the allocation, and then control the assignment of their upstream traffic to the time slots.

Claims

1. A gateway device for allocating capacity for upstream satellite transmissions to a plurality of subscriber terminals, the gateway device comprising:

an upstream traffic classification unit configured to;

receive one or more sets of data from each of the plurality of subscriber terminals signaling capacity requests for upstream satellite transmissions for a time period;

identify a subset of the requested capacity based at least in part on transmission specifications limiting latency and packet spacing variance, the limiting exceeding a threshold level; and

classify the identified subset as prioritized traffic;

an upstream resource allocation unit, communicatively coupled with the upstream traffic classification unit, and configured to;

allocate a first set of time slots within the time period for the prioritized traffic, the first set allocated according to the transmission specifications;

subsequently allocate a second set of time slots within the time period to at least a subset of the capacity requests not classified as prioritized traffic; and

generate a combined allocation for the time period for a first one of the plurality of subscriber terminals, the combined allocation comprising a generalized block of time slots for the time period to be used as determined by the first subscriber terminal; and

a transmitting unit, communicatively coupled with the upstream resource allocation unit, and configured to transmit the combined allocation in a broadcast signal directed at the first subscriber terminal.

2. The gateway device of claim 1, wherein the upstream resource allocation unit is further configured to:

identify, for allocation to the prioritized traffic for the time period, a subset of a plurality of frequency channels for use in upstream satellite communications,

wherein the second set of time slots associated with the first subscriber terminal is allocated to one or more of the subset of the plurality of frequency channels for the time period.

3. The gateway device of claim 2, wherein the upstream resource allocation unit is further configured to:

exclude subscriber terminals not associated with the prioritized traffic for the time period from being allocated capacity on the subset of the plurality of frequency channels for the time period.

4. The gateway device of claim 1, wherein the upstream resource allocation unit is further configured to:

identify an adjacent subset of a plurality of frequency channels for use in upstream satellite communications for allocation to the prioritized traffic; and

prioritizing the second set of time slots for the first subscriber terminal over the second set of time slots for other subscriber terminals in the subsequent allocation for the adjacent subset.

5. The gateway device of claim 1, wherein the others of the second set of time slots are allocated to the adjacent subset.

6. The gateway device of claim 1, wherein the upstream resource allocation unit is configured to allocate at least a subset of the second set of time slots in a contention basis to two or more of the plurality of subscriber terminals.

7. The gateway device of claim 1, wherein,

the transmission specifications limiting latency specify a maximum delay before transmission at one of the plurality of subscriber terminals;

and

the transmission specifications limiting packet spacing variance specify substantially equidistant spacing between each of a series of packets.

8. The gateway device of claim 1, wherein the upstream resource allocation unit is further configured to:

identify a frequency channel of a plurality of frequency channels in a multi-frequency time-division multiple access system for allocation to the prioritized traffic,

wherein the second set of time slots for the first subscriber terminal is given priority over others of the second set of time slots for allocation to the frequency channel

9. The gateway device of claim 1, wherein,

the first set of time slots and the second set of time slots are allocated across a plurality of frequency channels for use in upstream satellite communications;

the frequency channels comprise frequency channels in a multi-frequency time-division multiple access system; and

the prioritized traffic comprises voice over internet protocol services, conferencing services, and interactive multimedia services.

10. The gateway device of claim 1, wherein at least a subset of the one or more sets of data from each of the plurality of subscriber terminals comprises a resource request message including a requested rate, packet size, and type.

11. The gateway device of claim 1, wherein at least a subset of the one or more sets of data from each of the plurality of subscriber terminals comprises a type field from a data packet transmitted from the first subscriber terminal to a network through the gateway device.

12. A method for allocating capacity for upstream satellite transmissions among a plurality of subscriber terminals, the method comprising:

receiving one or more sets of data from each of the plurality of subscriber terminals signaling capacity requests for upstream satellite transmissions for a time period;

identifying a subset of the requested capacity with transmission specifications limiting latency and packet spacing variance, the limiting exceeding a threshold level;

classifying the identified subset as prioritized traffic;

allocating a first set of time slots within the time period for the prioritized traffic, the first set allocated according to the transmission specifications;

subsequently allocating a second set of time slots within the time period to at least some of the capacity requests not classified as prioritized traffic; and

generating a combined allocation for the time period for each of the plurality of subscriber terminals, the combined allocation comprising a generalized block of time slots for the time period to be used as determined by respective subscriber terminal.

13. The method of claim 12, the method further comprising:

transmitting the combined allocation in a broadcast signal directed at the first subscriber terminal.

14. A system for allocating capacity for upstream satellite transmissions to a plurality of subscriber terminals, the system comprising:

a gateway device configured to;

receive capacity requests for the upstream satellite communications, wherein a subset of the capacity requests includes transmission specifications limiting latency and packet spacing variance, the limiting exceeding a threshold level;

classify the identified subset as prioritized traffic;

allocate a first set of time slots within a time period for the prioritized traffic, the first set allocated according to the transmission specifications;

subsequently allocate a second set of time slots within the time period to at least some of the capacity requests not classified as prioritized traffic; and

transmit a combined allocation for the time period for a first one of the plurality of subscriber terminals, the combined allocation comprising a generalized block of time slots for the time period to be used as determined by the first subscriber terminal; and

the first subscriber terminal, communicatively coupled with the gateway device via a satellite, and configured to;

receive the combined allocation transmitted from the gateway device;

classify a subset of traffic to be transmitted as prioritized subscriber terminal traffic;

dynamically assign the subset of traffic to the combined allocation according to applicable transmission specifications limiting latency and packet spacing variance; and

subsequently assign the traffic not classified as prioritized subscriber terminal traffic to the combined allocation.

15. The system of claim 14, wherein the subscriber terminal is configured to identify the subset of traffic to be transmitted as prioritized subscriber terminal traffic according to a different set of criteria than the threshold level for transmission specifications limiting latency and packet spacing variance defined by the gateway device.

16. A subscriber terminal device for requesting capacity for upstream satellite transmissions, the device comprising:

a resource request unit configured to generate capacity requests for each of a plurality of streams, wherein at least a subset of the capacity requests is associated with transmission specifications exceeding threshold limitations on latency and packet spacing variance;

an upstream mapping unit configured to;

receive, in response to the capacity requests, an allocation of time slots for a time period for the subscriber terminal device, the allocation comprising a block of time slots unassigned to particular streams of the plurality of streams;

classify a subset of data traffic to be transmitted in the time period by the subscriber terminal device as prioritized subscriber terminal traffic, the classification based at least in part on the threshold limitations on latency and packet spacing variance;

dynamically assign the prioritized subscriber terminal traffic to the allocation in a first set of time slots; and

subsequently assign the data traffic not classified as prioritized subscriber terminal traffic to the allocation in a second set of time slots; and

a transmitting unit communicatively coupled with the upstream mapping unit and resource request unit, and configured to;

transmit the capacity requests upstream for scheduling; and

transmit the traffic to be transmitted upstream according to assignments to the first set of time slots and the second set of time slots.

17. The subscriber terminal device of claim 16, wherein the upstream mapping unit is configured to identify the subset based at least in part on the threshold limitations on latency and packet spacing variance.

18. The subscriber terminal device of claim 16, wherein the allocation of time slots comprises time slots in a first frequency channel of a plurality of frequency channels in a multi-frequency time-division multiple access system for upstream satellite communications.

19. The subscriber terminal device of claim 18, wherein,

the allocation of time slots includes a first subset of time slots conforming with the limitations on packet spacing variance, the first subset dynamically assigned to the prioritized subscriber terminal traffic based at least in part on the conformance;

and

the allocation of time slots includes a second subset of time slots failing to conform with the limitations on packet spacing variance.

20. The subscriber terminal device of claim 16, wherein the upstream mapping unit is configured to:

the first set of time slots is assigned to a first frequency channel, wherein the allocation of time slots in the first frequency channel conforms with the limitations on packet spacing variance; and

the second set of time slots is assigned to a second frequency channel, the allocation of time slots in the second frequency channel failing to conform with the limitations on packet spacing variance.

21. The subscriber terminal device of claim 16, wherein the upstream mapping unit is further configured to assign a set of traffic to the allocation in the first set of time slots without the resource request unit generating a capacity request for the first set of data.

22. The subscriber terminal device of claim 16, wherein,

the transmission specifications limiting latency specify a maximum packet size;

and

the transmission specifications limiting packet spacing variance specify substantially equidistant spacing between each of a series of packets.

23. The subscriber terminal device of claim 16, wherein the resource request unit is configured to generate capacity requests comprising resource request messages including a requested rate, maximum latency, and duration.

24. The subscriber terminal device of claim 16, wherein the resource request unit is configured to generate capacity requests by generating data for transmission with an appended type field to signal the capacity request.

25. A method of assigning time slots for upstream satellite communications, the method comprising:

transmitting capacity requests for each of a plurality of different streams, wherein at least a subset of the capacity requests is associated with transmission specifications including limitations on latency and packet spacing variance;

receiving, in response to the capacity requests, an allocation of time slots for a time period, the allocation comprising a block of time slots unassigned to particular streams of the plurality of different streams;

identifying a subset of data traffic to be transmitted in the time period as prioritized subscriber terminal traffic, the identification based at least in part on a determination that the subset includes limitations on latency and packet spacing variance that exceed a threshold level;

dynamically assigning the prioritized subscriber terminal traffic to the allocation in a first set of time slots;

subsequently assigning the data traffic not classified as prioritized subscriber terminal traffic to the allocation in a second set of time slots; and

transmitting the traffic to be transmitted upstream according to assignments to the first set of time slots and the second set of time slots.