Low-cost satellite communication system
First Claim
1. A communication system comprising:
- a base station configured to receive a plurality of transmission messages on an information bandwidth, the base station including;
a plurality of direct sequence spread spectrum correlators for demodulating transmission messages based on a predetermined direct sequence spread spectrum code, each correlator configured to utilize the predetermined direct sequence spread spectrum code,whereina first transmission message of the plurality of transmission messages has a respective start time and a respective end time,a second transmission message of the plurality of transmission messages has a respective start time that is between the respective start time and end time of the first transmission message,at least one of the respective start time of the first transmission message and the respective start time of the second transmission message is independent of the base station, andthe base station is configured to distinguish between the first and second messages based on the respective start times of the first and second transmission messages.
1 Assignment
0 Petitions
Accused Products
Abstract
A communication system is provided that allows the use of low-cost, low-power remote terminal units that communicate substantially asynchronously and independently to a base station. To minimize cost and complexity, the remote terminal units are configured similarly, including the use of substantially identical transmission schemes, such as a common Direct Sequence Spread Spectrum (DSSS) code. To minimize collisions among transmissions, the communication system is designed to use a high-gain antenna with a limited field of view, to limit the number of cotemporaneous, or overlapping transmissions that are received at the base station. To cover a wide area, the limited field of view is swept across the area of coverage. To overcome potential losses caused by collisions, the remote terminal units are configured to repeat transmissions; to minimize repeated collisions, the repeat interval and/or duration is randomized.
120 Citations
7 Claims
-
1. A communication system comprising:
a base station configured to receive a plurality of transmission messages on an information bandwidth, the base station including; a plurality of direct sequence spread spectrum correlators for demodulating transmission messages based on a predetermined direct sequence spread spectrum code, each correlator configured to utilize the predetermined direct sequence spread spectrum code, wherein a first transmission message of the plurality of transmission messages has a respective start time and a respective end time, a second transmission message of the plurality of transmission messages has a respective start time that is between the respective start time and end time of the first transmission message, at least one of the respective start time of the first transmission message and the respective start time of the second transmission message is independent of the base station, and the base station is configured to distinguish between the first and second messages based on the respective start times of the first and second transmission messages. - View Dependent Claims (2, 3, 4, 5, 6, 7)
Specification