Increasing channel capacity of TDMA transmitters in satellite based networks
First Claim
1. A system for Time Division Multiple Access (TDMA) communications, comprising a plurality of one-way transmitters sharing a communication channel and at least one matching receiver, and a Global Navigation Satellite System (GNSS) decoder coupled to each of said transmitters, said transmitters configured to define:
- i) a transmission cycle divided to a set of adjacent time slots;
ii) a geographical partition of earth surface to cells; and
iii) a sub set of time slots, comprising a plurality of time slots from said set of time slots, allocated to each of said cells;
each transmitter configured to transmit during one time slot or less per transmission cycle, wherein said one time slot determined by each transmitter as following;
a) determining the start time of transmission cycles and time slots according to at least a timing signal and/or time data acquired from said GNSS decoder;
b) determining self location and the corresponding cell according to at least data acquired from said GNSS decoder;
c) selecting one time slot from the sub set of time slots allocated to said corresponding cell, in a random or pseudo-random way.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention discloses a method for increasing the channel capacity of a communications network, comprising a plurality of one-way TDMA transmitters sharing said channel, and at least one compatible receiver, by reducing transmission collisions among said transmitters. This is achieved by coupling a Global Navigation Satellite System (GNSS) decoder, such as a GPS receiver, to each transmitter, and limiting transmissions to discrete time slots, determined by timing signals provided by said GNSS. Further, this basic set of time slots is divided into several sub sets, and each transmitter selects a sub set of time slots according to its geographic location, in order to enable reusing time slots in spaced apart areas, as frequencies are reused in cellular networks. Then, each transmitter selects its own transmission time slot, from said sub set, in a way that statistically minimizes collisions among nearby transmitters. The present invention does not intend to ensure collision-free communications, yet is projected to reduce the transmission collision rate among simplex in nature transmitters, which have no means to detect other transmissions, or discover if a transmission was successful. One embodiment of this invention is related to distress radio beacons in satellite based Search and Rescue (SAR) systems, such as Cospas-Sarsat.
-
Citations
18 Claims
-
1. A system for Time Division Multiple Access (TDMA) communications, comprising a plurality of one-way transmitters sharing a communication channel and at least one matching receiver, and a Global Navigation Satellite System (GNSS) decoder coupled to each of said transmitters, said transmitters configured to define:
- i) a transmission cycle divided to a set of adjacent time slots;
ii) a geographical partition of earth surface to cells; and
iii) a sub set of time slots, comprising a plurality of time slots from said set of time slots, allocated to each of said cells;
each transmitter configured to transmit during one time slot or less per transmission cycle, wherein said one time slot determined by each transmitter as following;
a) determining the start time of transmission cycles and time slots according to at least a timing signal and/or time data acquired from said GNSS decoder;
b) determining self location and the corresponding cell according to at least data acquired from said GNSS decoder;
c) selecting one time slot from the sub set of time slots allocated to said corresponding cell, in a random or pseudo-random way. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- i) a transmission cycle divided to a set of adjacent time slots;
-
17. A transmitter in a network for Time Division Multiple Access (TDMA) communications, comprising a plurality of such one-way transmitters sharing a communication channel and at least one matching receiver, and a Global Navigation Satellite System (GNSS) decoder coupled to each of said transmitters, said transmitters configured to define:
- i) a transmission cycle divided to a set of adjacent time slots;
ii) a geographical partition of earth surface to cells; and
iii) a sub set of time slots, comprising a plurality of time slots from said set of time slots, allocated to each of said cells;
each transmitter configured to transmit during one time slot or less per transmission cycle, wherein said one time slot determined by each transmitter as following;
a) determining the start time of transmission cycles and time slots according to at least a timing signal and/or time data acquired from said GNSS decoder;
b) determining self location and the corresponding cell according to at least data acquired from said GNSS decoder;
c) selecting one time slot from the sub set of time slots allocated to said corresponding cell, in a random or pseudo-random way.
- i) a transmission cycle divided to a set of adjacent time slots;
-
18. A computer program product in a computer readable medium for a transmitter in a network for Time Division Multiple Access (TDMA) communications, comprising a plurality of one-way transmitters sharing a communication channel and at least one matching receiver, and a Global Navigation Satellite System (GNSS) decoder coupled to each of said transmitters, said transmitters configured to define:
- i) a transmission cycle divided to a set of adjacent time slots;
ii) a geographical partition of earth surface to cells; and
iii) a sub set of time slots, comprising a plurality of time slots from said set of time slots, allocated to each of said cells;
each transmitter configured to transmit during one time slot or less per transmission cycle, wherein said one time slot determined by each transmitter as following;
a) determining the start time of transmission cycles and time slots according to at least a timing signal and/or time data acquired from said GNSS decoder;
b) determining self location and the corresponding cell according to at least data acquired from said GNSS decoder;
c) selecting one time slot from the sub set of time slots allocated to said corresponding cell, in a random or pseudo-random way.
- i) a transmission cycle divided to a set of adjacent time slots;
Specification