Multiple access telephone extension systems and methods
First Claim
Patent Images
1. A telephone communications system, the system comprising:
- (a) a base unit comprising;
(i) a first transmitter subsystem,(ii) a first receiver subsystem, and(iii) means for connecting said first transmitter subsystem and said first receiver subsystem to a telephone line;
(b) an extension unit comprising;
(i) a second transmitter subsystem, and(ii) a second receiver subsystem;
each of said first and second transmitter subsystems comprising;
(a) means or converting analog telephone communications signals to digital data signals;
(b) means for generating a transmission carrier controlled by at least one multiple access means, said at least one multiple access means being selected form the group consisting of;
(i) time division multiple access multiplexing means for controlling the times at which the digital data signals are transmitted; and
(ii) frequency division multiple access means for changing said transmission carrier'"'"'s frequency;
(c) means for generating a pseudonoise code;
(d) means for modulating said transmission carrier by said digital data signals and said pseudonoise code to produce a direct spread code division multiple access signal; and
(e) means for coupling said direct spread code division multiple access signal to a communications medium;
and each of said first and second receiver subsystems comprising;
(a) means for receiving said direct spread code division multiple access signal from said communications medium;
(b) means for recovering said modulated transmission carrier from said received direct spread code division multiple access signal; and
(c) means for demodulating said recovered modulated transmission carrier to produce digital data corresponding to said analog telephone communications signals.
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Abstract
A method and system for conducting multiple access simultaneous telephone communications in full duplex either over the power lines of a building or using RF transmission. It employs a combination of multiple access techniques selected from among the following: time division, code division, and frequency division. The following features result: a) security coding to prevent unauthorized access and eavesdropping, b) multiple simultaneous conversations through identical and closely coupled transmission media, c) non-interference to other communications systems and users, and d) processing gain for operating in noisy environments.
303 Citations
19 Claims
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1. A telephone communications system, the system comprising:
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(a) a base unit comprising; (i) a first transmitter subsystem, (ii) a first receiver subsystem, and (iii) means for connecting said first transmitter subsystem and said first receiver subsystem to a telephone line; (b) an extension unit comprising; (i) a second transmitter subsystem, and (ii) a second receiver subsystem;
each of said first and second transmitter subsystems comprising;(a) means or converting analog telephone communications signals to digital data signals; (b) means for generating a transmission carrier controlled by at least one multiple access means, said at least one multiple access means being selected form the group consisting of; (i) time division multiple access multiplexing means for controlling the times at which the digital data signals are transmitted; and (ii) frequency division multiple access means for changing said transmission carrier'"'"'s frequency; (c) means for generating a pseudonoise code; (d) means for modulating said transmission carrier by said digital data signals and said pseudonoise code to produce a direct spread code division multiple access signal; and (e) means for coupling said direct spread code division multiple access signal to a communications medium; and each of said first and second receiver subsystems comprising; (a) means for receiving said direct spread code division multiple access signal from said communications medium; (b) means for recovering said modulated transmission carrier from said received direct spread code division multiple access signal; and (c) means for demodulating said recovered modulated transmission carrier to produce digital data corresponding to said analog telephone communications signals. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A telephone communications base unit comprising:
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(a) a transmitter subsystem, (b) a receiver subsystem, and (c) means for connecting said transmitter subsystem and said receiver subsystem to a telephone line; said transmitter subsystem comprising; (a) means for converting first analog telephone communications signals to first digital data signals; (b) means for generating a first transmission carrier controlled by at least one multiple access means, said at least one multiple access means being selected from the group consisting of; (i) time division multiple access multiplexing means for controlling the times at which said first digital data signals are transmitted; and (ii) frequency division multiple access means for changing said transmission carrier'"'"'s frequency; (c) means for generating a pseudonoise code; (d) means for modulating said first modulated transmission carrier by said first digital data signals and said pseudonoise code to produce a first direct spread code division multiple access signal; and (e) means for coupling said first direct spread code division multiple access signal to a communications medium; and said receiver subsystem comprising; (a) means for receiving a second direct spread code division multiple access signal from said communications medium; (b) means for recovering a second modulated transmission carrier from said second direct spread code division multiple access signal; and (c) means for demodulating said second modulated transmission carrier to produce second digital data corresponding to second analog telephone communications signals. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A telephone communications extension unit comprising:
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(a) a transmitter subsystem, and (b) a receiver subsystem; said transmitter subsystem comprising; (a) means for converting first analog telephone communications signals to first digital data signals; (b) means for generating a first transmission carrier controlled by at least one multiple access means, said at least one multiple access means being selected form the group consisting of; (i) time division multiple access multiplexing means for controlling the times at which said first digital data signals are transmitted; and (ii) frequency division multiple access means for changing said transmission carrier'"'"'s frequency; (c) means for generating a pseudonoise code; (d) means for modulating said first modulated transmission carrier by said first digital data signals and said pseudonoise code to produce a first direct spread code division multiple access signal; and (e) means for coupling said first direct spread code division multiple access signal to a communications medium; and said receiver subsystem comprising; (a) means for receiving a second direct spread code division multiple access signal from said communications medium; (b) means for recovering a second modulated transmission carrier from said second direct spread code division multiple access signal; and (c) means for demodulating said second modulated transmission carrier to produce second digital data corresponding to second analog telephone communications signals. - View Dependent Claims (15, 16, 17)
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18. A method for telephone communications between a first unit and a second unit, the method comprising the steps of:
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(a) said first unit converting analog telephone communications signals to digital data signals; (b) said first unit generating a transmission carrier controlled by at least one multiple access technique selected form the group consisting of; (i) time division multiple access for controlling the times at which the transmission carrier is transmitted; and (ii) frequency division multiple access for changing said transmission carrier'"'"'s frequency; (c) said first unit generating pseudonoise code; (d) said first unit modulating said transmission carrier with said digital data signals and said pseudonoise code to produce a direct spread code division multiple access signal; (e) said first unit transmitting said direct spread code division multiple access signal to said second unit; (f) said second unit recovering said modulated transmission carrier from said direct spread code division multiple access signal; and (g) said second unit demodulating said modulated transmission carrier to produce digital data corresponding to said analog telephone communications signals. - View Dependent Claims (19)
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Specification