Upstream resource optimization

• US 7,995,515 B2
• Filed: 07/17/2008
• Issued: 08/09/2011
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Thesling, William H.
• Primary Examiner(s): Phunkulh; Bob A
• Application Number:
  US12/174,674
• Publication Number:
  US 20080298299A1
• Time in Patent Office: 1,118 Days
• Field of Search: None
• US Class Current: 370/322
• 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 for allocating capacity for upstream satellite transmissions to a plurality of user terminals, the gateway comprising:

an upstream traffic classifier configured to;

receive requests for upstream satellite transmissions capacity from the plurality of user terminals for a time period;

identify a subset of the requested capacity with transmission specifications limiting latency and packet spacing variance; and

classify the identified subset as prioritized traffic;

an upstream resource allocator, communicatively coupled with the upstream traffic classifier, 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 requested capacity not classified as prioritized traffic; and

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

a transmitter, communicatively coupled with the upstream resource allocator, configured to transmit the combined allocation in a broadcast signal directed at the first user terminal.

2. The gateway of claim 1, wherein the upstream resource allocator 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 user terminal is allocated to one or more of the subset of the plurality of frequency channels for the time period.

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

exclude user 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 of claim 1, wherein the upstream resource allocator 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 user terminal over the second set of time slots for other user terminals in the subsequent allocation for the adjacent subset.

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

6. The gateway of claim 1, wherein the upstream resource allocator 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 user terminals.

7. The gateway of claim 1, wherein,

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

and

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

8. The gateway of claim 1, wherein the upstream resource allocator 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 user terminal is given priority over others of the second set of time slots for allocation to the frequency channel.

9. The gateway 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 of claim 1, wherein at least a subset of the requests from each of the plurality of user terminals comprises a resource request message including a requested rate, packet size, and type.

11. The gateway of claim 1, wherein at least a subset of the requests from each of the plurality of user terminals comprises a type field from a data packet transmitted from the first user terminal to a network through the gateway.

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

receiving requests for upstream satellite transmissions capacity, from each of the plurality of user terminals for a time period;

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

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 requested capacity not classified as prioritized traffic;

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

transmitting an applicable portion of the combined allocation in a broadcast signal directed at one of the respective user terminals.

13. The method of claim 12, further comprising:

identifying 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 one of the respective user terminals over the second set of time slots for other user terminals in the subsequent allocation for the adjacent subset.

14. The method of claim 12, wherein at least a subset of the requests from the plurality of user terminals comprises a resource request message including a requested rate, packet size, and type.

15. The method of claim 12, wherein the subset of the requested capacity is identified because the limitations on latency exceed a threshold level.

16. The method of claim 12, wherein the subset of the requested capacity is identified because the limitations on and packet spacing variance exceed a threshold level.

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

a gateway configured to;

receive capacity requests for the upstream satellite communications, a subset of the capacity requests including transmission specifications limiting latency and packet spacing variance;

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 user terminals, the combined allocation comprising a block of time slots for the time period to be used as determined by the first user terminal; and

the first user terminal, communicatively coupled with the gateway via a satellite, configured to;

receive the combined allocation transmitted from the gateway;

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

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

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

18. The system of claim 17, wherein the user terminal is configured to identify the subset of traffic to be transmitted as prioritized user terminal traffic according to a different set of criteria than the transmission specifications limiting latency and packet spacing variance defined by the gateway.

19. A user terminal for requesting capacity for upstream satellite transmissions, the terminal comprising:

a resource requester configured to generate capacity requests for each of a plurality of streams, at least a subset of the capacity requests associated with transmission specifications including limitations on latency and packet spacing variance;

an upstream mapper configured to;

receive, in response to the capacity requests, an allocation of time slots for a time period for the user terminal, 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 user terminal as prioritized user terminal traffic, the classification based at least in part on the limitations on latency and packet spacing variance;

assign the prioritized user terminal traffic to a first set of time slots of the allocation of time slots; and

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

a transmitter communicatively coupled with the upstream mapper and resource requester, configured to;

transmit the capacity requests upstream for scheduling; and

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

20. The user terminal of claim 19, wherein the upstream mapper is configured to identify the subset based at least in part on the limitations on latency and packet spacing variance.

21. The user terminal of claim 19, 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.

22. The user terminal of claim 21, wherein,

the allocation of time slots includes a first subset of time slots conforming with the limitations on packet spacing variance, the first subset assigned to the prioritized user 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.

23. The user terminal of claim 19, wherein,

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.

24. The user terminal of claim 19, wherein the upstream mapper is further configured to assign a set of traffic to the allocation in the first set of time slots without the resource requester generating a capacity request for the first set of data.

25. The user terminal of claim 19, 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.

26. The user terminal of claim 19, wherein the resource requester is configured to generate capacity requests comprising resource request messages including a requested rate, maximum latency, and duration.

27. The user terminal of claim 19, wherein the resource requester is configured to generate capacity requests by generating data for transmission with an appended type field to signal the capacity request.

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

transmitting capacity requests for each of a plurality of different streams, 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 user terminal traffic, the identifying based at least in part on a determination that the subset includes limitations on latency and packet spacing variance that exceed a threshold level;

assigning the prioritized user terminal traffic to a first set of time slots of the allocation of time slots;

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

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

29. The method of claim 28, further comprising:

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

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

30. A device for allocating capacity for upstream satellite transmissions among a plurality of user terminals, the device comprising:

means for receiving requests for upstream satellite transmissions capacity from the plurality of user terminals for a time period;

means for identifying a subset of the requested capacity with transmission specifications limiting latency and packet spacing variance;

means for classifying the identified subset as prioritized traffic;

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

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

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

31. A device for assigning time slots for upstream satellite communications, the device comprising:

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

means for 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;

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

means for assigning the prioritized user terminal traffic to a first set of time slots of the allocation of time slots;

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

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