Satellite communication system with multiple variable data rate carrier

• US 6,577,847 B2
• Filed: 01/24/2002
• Issued: 06/10/2003
• Est. Priority Date: 01/29/2001
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Van Willigen, Engelbertus
• Primary Examiner(s): MAUNG, NAY AUNG
• Application Number:
  US10/056,084
• Publication Number:
  US 20020115408A1
• Time in Patent Office: 502 Days
• Field of Search: 455/10, 455/12.1, 455/13.1, 455/13.2, 455/13.3, 455/13.4, 455/68, 455/69, 455/70, 375/344
• US Class Current: 455/13.1
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system

Abstract

Described is a satellite communication system 1 comprising a primary station 2, a communication satellite 3 and at least one secondary station 4. The primary station 2 transmits data signals 5 via the communication satellite 3 to the secondary station 4. The primary station 2 comprises a modulator 24 for modulating the data signals onto at least two differently FEC-encoded frequency carriers. The secondary station 4 comprises a tuner 32 for tuning to one of the frequency carriers in dependence on a tuning signal received from the primary station 2. The secondary station 4 further comprising signal quality determining means for determining at least an estimate of a signal quality of the frequency carrier presently tuned to. The secondary station 4 comprising retuning request transmit means for transmitting a retuning request signal to the primary station 2 when the estimate of the signal quality becomes lower than a predetermined threshold value. The primary station 2 comprises determining means for determining a frequency carrier with a better signal quality upon reception of the retuning request signal and tuning signal transmit means for transmitting the tuning signal indicating this frequency carrier to the secondary station 4. In this way, when the data signals 5 (which are modulated onto a certain frequency carrier) are received poorly (e.g. because of rain fading) the secondary station 4 can tune to a frequency carrier with a more robust FEC-encoding and the data signals 5 can be received without problems.

Claims

1. A satellite communication system (1) comprising a primary station (2), a communication satellite (3) and at least one secondary station (4), the primary station (2) transmitting data signals (5) via the communication satellite (3) to the secondary station (4), the primary station (2) comprising a modulator (24) for modulating the data signals (5) onto at least two differently FEC-encoded frequency carriers, the secondary station (4) comprising a tuner (32) for tuning to one of the frequency carriers in dependence on a tuning signal received from the primary station (2), the secondary station (4) further comprising signal quality determining means for determining at least an estimate of a signal quality of the frequency carrier presently tuned to, the secondary station (4) comprising retuning request transmit means for transmitting a retuning request signal to the primary station (2) when the estimate of the signal quality becomes lower than a predetermined threshold value, the primary station (2) comprising determining means for determining a frequency carrier with a higher signal quality upon reception of the retuning request signal and tuning signal transmit means for transmitting the tuning signal indicating this frequency carrier to the secondary station (4).

2. The satellite communication system (1) according to claim 1, wherein the tuning signal is transmitted from the primary station (2) via the communication satellite (3) to the secondary station (4).

3. The satellite communication system (1) according to claim 1, wherein the retuning request signal is transmitted from the secondary station (4) via the communication satellite (3) to the primary station (4).

4. A primary station (2) for use in a satellite communication system (1), the primary station (2) transmitting data signals (5) via a communication satellite (3) to a secondary station (4), the primary station (2) comprising a modulator (24) for modulating the data signals (5) onto at least two differently FEC-encoded frequency carriers, the primary station (2) comprising receiving means for receiving a retuning request signal from the secondary station (4), the primary station (2) further comprising determining means for determining a frequency carrier with a requested signal quality upon reception of the retuning request signal and tuning signal transmit means for transmitting the tuning signal indicating this frequency carrier to the secondary station (4).

5. The primary station (2) according to claim 4, wherein the tuning signal is transmitted via the communication satellite (3).

6. The primary station (2) according to claim 4, wherein the retuning request signal is received via the communication satellite (3).

7. A secondary station (4) for use in a satellite communication system (1), the secondary station (4) comprising receive means for receiving data signals (5) via a communication satellite (3) from a primary station (2), the data signals (5) being modulated onto at least two differently FEC-encoded frequency carriers, the secondary station (4) comprising a tuner (32) for tuning to one of the frequency carriers in dependence on a tuning signal received from the primary station (2), the secondary station (4) further comprising signal quality determining means for determining at least an estimate of a signal quality of the frequency carrier presently tuned to, the secondary station (4) comprising retuning request transmit means for transmitting a retuning request signal to the primary station (2) when the estimate of the signal quality becomes lower than a predetermined threshold value.

8. The secondary station (4) according to claim 7, wherein the tuning signal is received via the communication satellite (3).

9. The secondary station (4) according to claim 7, wherein the retuning request signal is transmitted via the communication satellite (3).

10. A method of transmitting data signals (5) from a primary station (2) via a communication satellite (3) to a secondary station (4), the method comprising:

the primary station (2) modulating the data signals (5) onto at least two differently FEC-encoded frequency carriers,

the secondary station (4) tuning to one of the frequency carriers in dependence on a tuning signal received from the primary station (2),

the secondary station (4) determining at least an estimate of a signal quality of the frequency carrier presently tuned to,

the secondary station (4) transmitting a retuning request signal to the primary station (2) when the estimate of the signal quality becomes lower than a predetermined threshold value,

the primary station (2) determining a frequency carrier with a higher signal quality upon reception of the retuning request signal

the primary station (2) transmitting the tuning signal indicating this frequency carrier to the secondary station (4).

11. The method according to claim 10, wherein the tuning signal is transmitted from the primary station (2) via the communication satellite (3) to the secondary station (4).

12. The method according to claim 10, wherein the retuning request signal is transmitted from the secondary station (4) via the communication satellite (3) to the primary station (4).