Multi-Dimensional Adaptive Transmission Technique

• US 20090175185A1
• Filed: 12/17/2008
• Published: 07/09/2009
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Gilat Satellite Networks Limited
• Original Assignee: Gilat Satellite Networks Limited
• Inventors: Tamam, Ronen, Laish, Isacc Ben, Pinchas, Magal
• Granted Patent: US 8,135,431 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18519 Operations control, administration or maintenance
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04B 7/18573 for operations control, administration or maintenance
• CPC Class Codes: H04B 7/18597 Arrangements for system physical machines management, i.e. for construction, operations control, administration, maintenance
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Method and apparatus for dynamically optimizing the transmission level of each remote terminal in a satellite-based communication network. Each remote terminal maintains quasi-error-free communication at the highest efficiency level available under changing link conditions and network configurations, without requiring the reservation of substantial power margins, which results in a much more efficient satellite network.

Claims

1. In a satellite system, a method for adjusting the transmission power of a remote terminal comprising entering an installation mode where installation mode is assumed whenever the remote terminal is installed or its configuration modified and a normal mode is assumed at other times.

2. The method of claim 1, including entering installation mode upon a change in the remote terminal'"'"'s hardware, including upon replacement of the indoor unit, upon replacement of the satellite transmitter or upon redeployment of the cables connecting the indoor unit and the satellite transmitter.

3. The method of claim 1, where installation mode includes:

erasing any previous transmit power range, including the maximal transmit power level;

determining the initial transmit power level using a predefined value;

sending a predefined number of logon messages at the determined initial transmit power;

increasing the transmit power for logon messages upon failing to receive acknowledgement for any of the logon messages transmitted; and

assuming normal mode once an acknowledgement is received.

4. The method of claim 3 further including setting transmit power back to an initial level if no acknowledgement is received and transmit power cannot be increased any further.

5. The method of claim 3, including determining the initial transmit power level using an installation parameter.

6. The method of claim 3 including configuring logon messages to follow the format of CSC bursts as defined by DVB-RCS (ETSI EN 301 790).

7. The method of claim 1, including configuring normal mode to include an admission phase and a session phase.

8. The method of claim 7, where the admission phase includes:

determining the initial transmit power level using a predefined back off from the highest maximal transmission level stored in the remote terminal'"'"'s non-volatile memory;

sending a predefined number of logon messages at the determined initial transmit power;

increasing the transmit power for logon messages upon failing to receive acknowledgement for any of the logon messages transmitted; and

assuming session phase once an acknowledgement is received.

9. The method of claim 8, further including configuring the transmit power back to the initial level if no acknowledgement is received at maximal transmit power, where maximal transmit power is determined by the indoor unit'"'"'s maximal output power.

10. The method of claim 8, including configuring logon messages to follow the format of CSC bursts as defined by DVB-RCS (ETSI EN 301 790).

11. The method of claim 7 including configuring the session phase for the remote terminal to transmit maintenance packets to the hub at either automatically calculated or predefined intervals and configuring each maintenance packet to include an information item containing the delta between the transmit power at which the maintenance packet is transmitted and the maximal transmit power as last measured and/or calculated by the remote terminal.

12. The method of claim 11, including configuring the maintenance packets to follow the format of SYNC bursts as defined by DVB-RCS (ETSI EN 301 790) with the extension of the information item located after all mandatory information items defined by DVB-RCS.

13. The method of claim 11, including configuring the maintenance packets to follow the format of TRF bursts as defined by DVB-RCS (ETSI EN 301 790), including any proprietary modifications to the format defined by DVB-RCS.

14. The method of claim 11, including measuring the reception level of each received maintenance packet and sending a reply packet over the forward link containing the measured reception level of the maintenance packet.

15. The method of claim 14, including configuring the reception level to be E-S/N0 of the received packet'"'"'s signal.

16. The method of claim 14, including configuring the reception level to be C/N of the received packet'"'"'s signal.

17. The method of claim 14, including configuring the reply packet to be transmitted as part of a Correction Message Table (CMT) as defined by DVB-RCS (ETSI EN 301 790).

18. The method of claim 14, including configuring the reply packet to be transmitted as part of a correction message descriptor included in a unicast Terminal Information Message (TIM) as defined by DVB-RCS (ETSI EN 301 790).

19. The method of claim 14, including configuring the remote terminal to adjust its transmit power level on a transmission by transmission basis according to the timeslot type (symbol rate, modulation and coding combination) assigned for each transmission and according to the reception level information included in the reply packets.

20. The method of claim 19, including determining a decline in reception level as reported in reply packets and configuring the remote terminal to increase its transmit power level up to the maximal transmit power level as limited either by the indoor unit capabilities or the satellite transmitter'"'"'s maximal output power at the maximal transmit power point.

21. The method of claim 14, further including:

calculating a maximal reception level as the sum of the measured reception level of a received maintenance packet and the delta value contained in the maintenance packet;

storing a maximal reception level for each remote terminal; and

updating the maximal reception level for a remote terminal upon reception of every maintenance packet from the remote terminal.

22. The method of claim 21, including performing the following steps upon allocating capacity to a remote terminal:

retrieving the last maximal reception level value for the remote terminal;

determining the most efficient timeslot type for which the nominal reception level is still below the maximal reception level for the remote terminal; and

assigning the remote terminal timeslots of the type.

23. The method of claim 22, further including where there is a lack of sufficient suitable timeslots of the most efficient type, assigning timeslots of one or more less efficient types in which their nominal reception level is still below the maximal reception level of the remote terminal.

24. The method of claim 23, including determining to assign timeslots of less efficient types from considerations other than lack of suitable timeslots of the most efficient type.

38. The method of claim 1 where the satellite network is over Ku-band.

39. The method of claim 1 where the satellite network is over C-band.

40. The method of claim 1 where the satellite network is over Ka-band.

25. In a satellite system, a method comprising:

transmitting a predefined number of maintenance packets at the same transmit power level;

receiving reply packets over a forward link containing reception level measurements of transmitted maintenance packets;

calculating the average reception level for the transmitted maintenance packets;

calculating a gain equivalent as the difference between an average reception level and a satellite transmitter'"'"'s input power level;

repeatedly increasing the transmit power level; and

repeating the above steps for each transmit power level, until about a 1 dB drop in gain is detected and the about 1 dB compression point is found;

calculating the maximal transmit power level as the satellite transmitter'"'"'s highest input power level for which the calculated gain is 1 dB higher than the gain measured at the 1 dB compression point; and

storing the calculated maximal transmit power level in non-volatile memory, if the already stored value is lower or if no previous value is available.

26. The method of claim 25, wherein the maximal transmit power level corresponds with a found 1 dB compression point.

27. The method of claim 25 further including a step of calculating the 1 dB compression point as the average of a found 1 dB compression point value with a predefined number of previously found 1 dB compression point values.

28. The method of claim 25, further comprising increasing in transmit power level is stopped once the calculated average reception level reaches the maximal reception level needed according to the most demanding timeslot type available over the return link plus a predefined margin.

29. The method of claim 28, including repeating the sequence at predefined intervals.

30. The method of claim 28, including basing reported reception levels and the calculated average reception level on E-S/N0 measurements by a hub.

31. The method of claim 28, including basing reported reception levels and the calculated average reception levels on C/N measurements by a hub.

32. The method of claim 28, where the satellite transmitter'"'"'s input power level is calculated based on the current settings of any configurable attenuators along the transmit path.

33. The method of claim 28, where maintenance packets are configured to follow the format of SYNC bursts as defined by DVB-RCS (ETSI EN 301 790) with the extension of the information item located after all mandatory information items defined by DVB-RCS.

34. The method of claim 28, where maintenance packets are configured to follow the format of TRF bursts as defined by DVB-RCS (ETSI EN 301 790), including any proprietary modifications to the format defined by DVB-RCS.

35. The method of claim 3 further combined with the method of claim 28.

36. The method of claim 35 further including:

comparing the gain equivalent results of the first and second transmit-power levels;

remaining in Installation Mode, if a drop in gain is larger than a predefined threshold; and

assuming normal mode after maximal transmit power level is stored in non-volatile memory.

37. In a satellite system, a method comprising:

measuring and/or gathering statistics on the distribution of allocations between the different timeslot types;

calculating the percentage of remote terminals, which may transmit using any of same timeslot types; and

reconfiguring the blend of timeslot types and channels of the return link, adjusting it to the changing needs of the network as reflected by said measurements and calculations.