Granted Patent B2

US 7,075,950 · App. 10/022,891 · Granted Jul 11, 2006

Abstract

Claims (27)

1. A Program Clock Reference (PCR) correction method in a transmission over a downlink in an integrated multispot satellite communication system (S) in which said downlink is transmitted in burst mode and comprises a plurality of multiplexed, modulated and compressed packets, corresponding to at least one user (a 1 , a 2 , b 1 , c 1 , c 2 , c 3 and c 4 ), wherein said method of correcting a Program Clock Reference comprises calculating a distance (d) between a real position of a packet (a 12 ) and an estimated position of said packet, the estimated position being that which said packet (a 12 ) would occupy if the downlink had not been compressed in a modulation and compression stage.

2. The method of claim 1 , wherein said PCR correction is defined by the following formula:

C PCR =t dpack ·d

where:

“C PCR ” is the correction factor;

“d” is the distance between the real position and the estimated position of the packet; and

“t dpack ” is the duration in time of a packet in the downlink frame.

3. Method according to claim 1 in which said distance (d) is defined by the following formula:

d

=

n

d

-

n

dt

n

ut

·

n

u

where:

n d is the number of the downlink position of the packet in process;

n dt is the total number of packets in the downlink frame;

n ut is the total number of packets per frame and user; and

n u is the number of the uplink position of the packet in process, and where both n d and n u start counting from zero.

4. Method according to claim 1 in which said transmission is carried out in MPEG2 transport streams in TDMA format.

5. An integrated multispot satellite communication system (S) for carrying out the method of claim 1 .

Assignments (9)