Variable chip rate code-division multiple access
First Claim
1. A method of communicating multiple signals over a common communications link comprising:
- modulating first input signals with respective first codes of low cross-correlation to obtain a first set of modulated signals at a first chip rate, each first modulated signal having a first bandwidth; and
modulating second input signals with respective second codes of low cross correlation relative to each other and relative to the first codes to obtain a second set of modulated signals at a second chip rate, different from said first chip rate each second modulated signal having a second bandwidth, there being spectral overlap between the first and second sets of modulated signals.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of communicating multiple signals over a common communications link by modulating first input signals with respective first codes of low cross-correlation to obtain a first set of modulated signals at a first chip rate. The input signals can be, for example, digitized audio or video signals, or data signals. The second input signals are of a data rate higher than the first input signals, and the second codes are of a dimension greater than the first codes. The second input signal or signals are modulated with respective second codes of low cross correlation relative to each other and relative to the first codes, resulting in a second set of modulated signals at a second chip rate such that there is spectral overlap between the first and second sets of modulated signals. The first and second sets of modulated signals are preferably modulated with different noise signals to spread the spectrum of each. In a preferred embodiment, the first and second codes are Walsh codes of different dimensions.
94 Citations
41 Claims
-
1. A method of communicating multiple signals over a common communications link comprising:
-
modulating first input signals with respective first codes of low cross-correlation to obtain a first set of modulated signals at a first chip rate, each first modulated signal having a first bandwidth; and modulating second input signals with respective second codes of low cross correlation relative to each other and relative to the first codes to obtain a second set of modulated signals at a second chip rate, different from said first chip rate each second modulated signal having a second bandwidth, there being spectral overlap between the first and second sets of modulated signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
-
-
22. An apparatus for communicating multiple signals over a common communications link comprising:
-
a first modulation means for modulating first input signals with respective first codes of low cross-correlation to obtain a first set of modulated signals at a first chip rate, each first modulated signal having a first bandwidth; and a second modulation means for modulating second input signals with respective second codes of low cross correlation relative to each other and relative to the first codes to obtain a second set of modulated signals at a second chip rate, different from said first chip rate each second modulated signal having a second bandwidth, there being spectral overlap between the first and second sets of modulated signals. - View Dependent Claims (23, 24, 25)
-
-
26. A transmitter for transmitting multiple signals over a common communications link comprising:
-
a modulator for combining first input signals with respective first codes of low cross-correlation to obtain a first set of modulated signals at a first chip rate, each first modulated signal having a first bandwidth, and for combining second input signals with respective second codes of low cross correlation relative to each other and relative to the first codes to obtain a second set of modulated signals at a second chip rate, different from said chip rate, each second modulated signal having a second bandwidth, there being spectral overlap between the first and second sets of modulated signals; and a link interface for transmitting the modulated signals over the communications link. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
-
-
41. A system for transmitting and receiving multiple signals over a common communications link comprising:
-
a modulator for combining first input signals with respective first codes of low cross-correlation to obtain a first set of modulated signals at a first chip rate, each first modulated signal having a first bandwidth, and for combining second input signals with respective second codes of low cross correlation relative to each other and relative to the first codes to obtain a second set of modulated signals at a second chip rate, different from said first chip rate, each second modulted signal having a second bandwidth, there being spectral overlap between the first and second sets of modulated signals; a link interface for transmitting the modulated signals over the communications link, and for receiving modulated signals from the communications link; a first demodulator for combining the received signals with the first codes to obtain a first set of demodulated signals at a first data rate; and a second demodulator for combining the received signals with the second codes to obtain a second set of demodulated signals at a second data rate.
-
Specification