System and method for multiple access short message communications
First Claim
1. A communications system utilizing time division multiple access (TDMA) and code division multiple access (CDMA) techniques for efficiently transmitting bursts of data from a plurality of users at different data rates to one or more receivers within the system, comprising:
- a timing reference for generating a precise timing signal and a corresponding precise time reference;
a plurality of transmitters, coupled to the timing reference for providing synchronization between the plurality of transmitters, for transmitting the bursts of data at precise times and time intervals and at a predetermined frequency within a TDMA superframe wherein synchronization between said plurality of transmitters and the one or more receivers is not needed; and
wherein the bursts of data is modulated with a carrier and is multiplied with a spreading sequence thereby permitting more than one of the plurality of transmitters to transmit at a same time and at the predetermined frequency.
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Accused Products
Abstract
The present invention describes a communications system that utilizes frequency division multiple access (FDMA), code division multiple access (CDMA), and time division multiple access (TDMA) techniques for providing efficient use of frequency spectrum while supporting a large number of transmitters/users (2-6). Many users of the communications system share a common frequency band, but each transmit their respective message bursts (50) at different and specific times via a TDMA technique. To facilitate synchronization of the TDMA technique, each transmitter of the system is synchronized to a common timing reference (1) thereby abating the need to maintain synchronization between the transmitters (2-6) and receivers (8-12) of the system. Each TDMA message is then transmitted via a spread spectrum technique by multiplying (82) the message burst to be transmitted by a pseudo-random sequence of ones and zeroes (84) and transmitting such spread spectrum message burst for reception by one or more receivers within the system.
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Citations
20 Claims
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1. A communications system utilizing time division multiple access (TDMA) and code division multiple access (CDMA) techniques for efficiently transmitting bursts of data from a plurality of users at different data rates to one or more receivers within the system, comprising:
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a timing reference for generating a precise timing signal and a corresponding precise time reference; a plurality of transmitters, coupled to the timing reference for providing synchronization between the plurality of transmitters, for transmitting the bursts of data at precise times and time intervals and at a predetermined frequency within a TDMA superframe wherein synchronization between said plurality of transmitters and the one or more receivers is not needed; and wherein the bursts of data is modulated with a carrier and is multiplied with a spreading sequence thereby permitting more than one of the plurality of transmitters to transmit at a same time and at the predetermined frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a communications system having a plurality of transmitters for transmitting bursts of data and a plurality of receivers for reception of the bursts of data, a method for allowing the plurality of transmitters to transmit bursts of data at a same time and at a predetermined frequency, the method comprising the steps of:
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synchronizing the plurality of transmitters to a common timing reference thereby abating the need to provide synchronization between the plurality of transmitters and the plurality of receivers; defining a time division multiple access (TDMA) superframe that includes a plurality of TDMA frames whereby each TDMA frame includes a plurality of time slots for transmission of the bursts of data by the plurality of transmitters; specifying a transmit opportunity for each of the plurality of transmitters including assigning each of the plurality of transmitters (i) a time slot within the plurality of TDMA frames for transmission, (ii) a position for specifying a first frame within the TDMA superframe for transmission, and (iii) an interval for specifying a number of frames between successive transmissions of the bursts of data; and spectrum spreading each of the bursts of data thereby permitting more than one of the plurality of transmitters to transmit at a same time and at the predetermined frequency. - View Dependent Claims (9, 10, 11, 12)
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13. A communications system utilizing time division multiple access (TDMA) and code division multiple access (CDMA) techniques for efficiently transmitting bursts of data, comprising:
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means for defining a TDMA superframe for specifying a plurality of time slots for transmitting bursts of data; a timing reference for generating a precise timing signal and a corresponding precise time reference; a plurality of transmitters, each coupled to the timing reference, for transmitting bursts of data at precise times and time intervals and at a predetermined frequency within the TDMA superframe wherein the bursts of data is modulated with a carrier and is multiplied with a spreading sequence; thereby permitting more than one of the plurality of transmitters to transmit at a same time and at the predetermined frequency; and a plurality of receivers for reception of the burst of data by the plurality of transmitters whereby synchronization between the plurality of transmitters and the plurality of receivers is not needed. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification