Technique for increasing the rain margin of a TDMA satellite communication system
AssigneeBell Telephone Laboratories, Incorporated
InventorsAnthony Acampora, Douglas O. Reudink
Life of this patent
Estimating the term…
Abstract
The present invention relates to a technique for increasing the rain margin of a satellite communication system which includes a satellite capable of transmitting multiple concurrent beams comprising time slot bursts in a TDMA mode. The present technique creates a small pool of TDMA time slots which are dedicated or formed at some instant of time by the rearrangement of traffic to permit the power normally transmitted in any portion of the multiple concurrent beams to be applied to one beam in a multiple fixed beam or limited scanning beam system or any portion of the beams which are directed at one ground station in a multiple unlimited scanning beam system for accessing a ground station experiencing, for example, a fade condition.
Claims6
A satellite arrangement for use in a TDMA multiple beam satellite communication system wherein multiple ground stations (16) normally operate to communicate with one another via the satellite using separate time slot burst intervals during a predetermined frame fromat, the satellite arrangement comprising:
- a plurality of up-link antenna ports (12.sub.1 -12.sub.n, FIG. 3;
- 50.sub.1 -50.sub.E, FIG. 4) capable of receiving up to n concurrent time slot bursts during each burst interval of the frame format from separate spaced-apart ones of the ground stations;
- a plurality of down-link antenna ports (12.sub.1 -12.sub.n, FIG. 3;
- 64.sub.1 -64.sub.E, FIG. 4) capable of launching each of the concurrently received time slot bursts towards the appropriate destination ground station;
- means (24, 34, 38, FIG. 3;
- 52.sub.1 -52.sub.n and 60.sub.1 -60.sub.n, FIG. 4) capable of directing each of the received time slot bursts between the appropriate up-link and down-link antenna ports;
- a plurality of amplifying means (32.sub.1 -32.sub.n, FIG. 3;
- 58.sub.1 -58.sub.n, FIG. 4) coupled to the directing means, each amplifying means being disposed to amplify the received time slot bursts directed thereto by the directing means prior to delivery to the appropriate down-link antenna port;
- and
- a controller (28, FIG. 3;
- 54, FIG. 4) capable of generating control signals to the directing means for causing the directing means to appropriately switch the received time slot bursts during each burst interval of the frame format between the appropriate up-link and down-link antenna ports via the plurality of amplifying means
- characterized in that
- the controller comprises means capable of generating both (a) first control signals to the directing means during certain predetermined time slot intervals of the frame format to cause the directing means to switch each of a plurality of n time slot bursts concurrently received at the up-link antenna ports through a separate one of the plurality of amplifying means for launching by the down-link antenna ports in a separate one of a plurality of n down-link beams to a separate destination ground station, and (b) second control signals to the directing means during the remaining predetermined time slot burst intervals of the frame format to cause the directing means to switch each of r concurrently received up-link time slot bursts, where n>r>1, between the up-link and down-link antenna ports through a separate predetermined number of amplifying means taken from the plurality of amplifying means before each of the r time slot bursts is directed to a separate one of r destination ground stations with the combined power of said separate predetermined number of amplifying means.
A method of increasing the rain margin in a TDMA satellite communication system comprising multiple ground stations which normally communicate with one another via a satellite using separate time slot burst intervals during a predetermined frame format of multiple burst intervals, the satellite comprising a plurality of up-link antenna ports (12.sub.1 -12.sub.n, 50.sub.1 -50.sub.E) and a plurality of down-link antenna ports (12.sub.1 -12.sub.n, 64.sub.1 -64.sub.E) capable of concurrently receiving and transmitting, respectively, a plurality of n beams associated with the various ground stations, a directing means (24, 34, 38;
- 52.sub.1 -52.sub.n and 60.sub.1 -60.sub.n) capable of directing each of the received time slot bursts between the appropriate up-link and down-link antenna ports, and a plurality of amplifying means (32.sub.1 -32.sub.n, FIG. 3;
- 58.sub.1 -58.sub.n, FIG. 4) capable of amplifying received time slot bursts directed thereto by the directing means by a predetermined amount,
- characterized in that
- the method comprises the steps of:
- (a) during a fade condition at a particular one of the receiving ground stations, receiving at the up-link antenna ports an up-link beam from a ground station desiring to communicate with the ground station experiencing the fade condition during a predetermined time slot burst interval of the frame format;
- (b) activating the directing means to distribute the signal received in the predetermined time slot burst interval of step (a) to a predetermined number of the plurality of amplifying means for separately amplifying the burst interval signal in each of the predetermined number of amplifying means by said predetermined amount and for directing the combined power generated by said predetermined number of amplifying means to the down-link antenna ports for launching toward the destination ground station experiencing the fade condition.
Dependencies are inferred from the claim text.