MULTI-USER DETECTION IN SATELLITE RETURN LINK

• US 20090290535A1
• Filed: 03/26/2009
• Published: 11/26/2009
• Est. Priority Date: 09/26/2006
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Dankberg, Mark D., Jaska, Kristi Ann
• Granted Patent: US 8,159,993 B2
• Time in Patent Office: Days
• US Class Current: 370/321
• CPC Class Codes: H04B 7/18582 Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access

Abstract

Use of multi-user detection (MUD) with a frequency-multiplexed satellite return link (scheduling algorithms, etc) is described. The satellite return link may utilize multi-frequency time division multiple access (MF-TDMA). The satellite return link may include a plurality of return sub-channels, wherein one or more of the return sub-channels may operate in a contention mode during some time periods and a non-contention mode at different time periods.

Claims

1. A satellite return link utilizing multi-frequency time division multiple access (MF-TDMA), the satellite return link comprising:

a first return sub-channel at a first frequency wirelessly coupled to a plurality of satellite modems;

a second return sub-channel at a second frequency wirelessly coupled to the plurality of satellite modems;

a third return sub-channel at a third frequency wirelessly coupled to the plurality of satellite modems, wherein;

the first return sub-channel operates in a non-contention mode at a first time,

the first return sub-channel operates in a contention mode at a second time different from the first time.

2. The satellite return link utilizing MF-TDMA according to claim 1, wherein a switch from non-contention to contention is performed after a determination that bandwidth is below a predetermined threshold.

3. The satellite return link utilizing MF-TDMA according to claim 1, wherein a switch from non-contention to contention is performed after a determination that latency is above a predetermined threshold.

4. The satellite return link utilizing MF-TDMA according to claim 1, wherein a subset of the plurality of satellite modems are instructed to use the first return sub-channel in the contention mode at the second time.

5. The satellite return link utilizing MF-TDMA according to claim 1, further comprising a multi-user detection (MUD) algorithm, wherein:

a subset of the plurality of satellite modems are instructed to use the first return sub-channel in the contention mode at the second time, and

the MUD algorithm is affected by the subset.

6. A method for multi-user detection in a satellite return link utilizing multi-frequency time division multiple access (MF-TDMA), the method comprising steps of:

coupling a first return sub-channel at a first frequency wirelessly to a plurality of satellite modems;

coupling a second return sub-channel at a second frequency wirelessly to the plurality of satellite modems;

coupling a third return sub-channel at a third frequency wirelessly to the plurality of satellite modems;

operating the first return sub-channel in a non-contention mode at a first time; and

operating the first return sub-channel in a contention mode at a second time different from the first time.

7. The method for multi-user detection in the satellite return link utilizing MF-TDMA according to claim 6, further comprising steps of:

determining if bandwidth is below a predetermined threshold; and

switching from non-contention to contention if the determining step determines that the bandwidth is below a predetermined threshold.

8. The method for multi-user detection in the satellite return link utilizing MF-TDMA according to claim 6, further comprising steps of:

determining if latency is above a predetermined threshold; and

switching from non-contention to contention if the determining step determines that the latency is above a predetermined threshold.

9. The method for multi-user detection in the satellite return link utilizing MF-TDMA according to claim 6, further comprising a step of:

instructing a subset of the plurality of satellite modems to use the first return sub-channel in the contention mode at the second time.

10. The method for multi-user detection in the satellite return link utilizing MF-TDMA according to claim 6, further comprising a step of:

instructing a subset of the plurality of satellite modems to use the first return sub-channel in the contention mode at the second time, wherein a multi-user detection (MUD) algorithm in the satellite return link is affected by the subset.