Method for transmitting wideband signals via a communication system adapted for narrow-band signal transmission
First Claim
1. A method of transmitting a first spread signal having a first bandwidth via a communication system adapted for communicating a second signal of a second bandwidth, the second bandwidth being narrower than the first bandwidth, the method comprising:
- modulating a first data signal with a first code to produce the first spread signal having the first bandwidth so that the first spread signal is orthogonal to the second signal of the second bandwidth;
transmitting the first spread signal and the second signal simultaneously so that the first bandwidth overlays the second bandwidth;
transmitting a pilot signal contemporaneously with transmission of the first spread signal; and
transmitting a control data signal, associated with a plurality of users on the first bandwidth, on a common control channel using a single Walsh code that is shared by a plurality of users in a TDMA (Time Division Multiple Access) protocol.
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Abstract
A communication system is used to transmit and receive data on a plurality of relatively narrow-band signals and wideband signals. The two signal types share a common electromagnetic spectrum by employing spreading gain and maintaining orthogonality between simultaneously transmitted wideband and narrow-band signals. Signal orthogonality is maintained by selectively choosing orthogonal codes and aligning or spacing a wideband carrier frequency with respect to the narrow-band carrier frequencies in accordance with the ratio of the wideband to the narrow-band chip frequencies. A pilot signal is preferably transmitted contemporaneously with the transmission of the first spread signal, and a control date signal, associated with a plurality of users on the first bandwidth, is transmitted on a common control channel using a single Walsh code that is shared by a plurality of users in a TDMA protocol.
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Citations
22 Claims
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1. A method of transmitting a first spread signal having a first bandwidth via a communication system adapted for communicating a second signal of a second bandwidth, the second bandwidth being narrower than the first bandwidth, the method comprising:
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modulating a first data signal with a first code to produce the first spread signal having the first bandwidth so that the first spread signal is orthogonal to the second signal of the second bandwidth; transmitting the first spread signal and the second signal simultaneously so that the first bandwidth overlays the second bandwidth; transmitting a pilot signal contemporaneously with transmission of the first spread signal; and transmitting a control data signal, associated with a plurality of users on the first bandwidth, on a common control channel using a single Walsh code that is shared by a plurality of users in a TDMA (Time Division Multiple Access) protocol. - View Dependent Claims (2, 3, 4)
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5. A method of transmitting a first spread signal having a first bandwidth via a communication system adapted for communicating a second signal of a second bandwidth, the second bandwidth being narrower than the first bandwidth, the method comprising:
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modulating a first data signal with a first code to produce the first spread signal having the first bandwidth so that the first spread signal is orthogonal to the second signal of the second bandwidth; transmitting the first spread signal and the second signal simultaneously so that the first bandwidth overlays the second bandwidth; and adaptively varying a data transmission rate associated with the first spread signal in response to a transmitter power level and a data error rate.
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6. A method of transmitting a first spread signal having a first bandwidth via a communication system adapted for communicating a second signal of a second bandwidth, the second bandwidth being narrower than the first bandwidth, the method comprising:
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modulating a first data signal with a first code to produce the first spread signal having the first bandwidth so that the first spread signal is orthogonal to the second signal of the second bandwidth; transmitting the first spread signal and the second signal simultaneously so that the first bandwidth overlays the second bandwidth; and comparing a message length to a predetermined threshold for message length, and transmitting the message using the spread spectrum access channel of the first bandwidth when the message length is less than the predetermined threshold.
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7. A method of transmitting a first spread signal having a first bandwidth via a communication system adapted for communicating a second signal of a second bandwidth, the second bandwidth being narrower than the first bandwidth, the method comprising:
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modulating a first data signal with a first code to produce the first spread signal having the first bandwidth so that the first spread signal is orthogonal to the second signal of the second bandwidth; transmitting the first spread signal and the second signal simultaneously so that the first bandwidth overlays the second bandwidth; and transmitting a pilot signal contemporaneously with transmission of the first spread signal, wherein a first carrier frequency associated with the first spread signal having a first chip rate has a spacing with respect to a second carrier frequency associated with the second signal having a second chip rate, the spacing being either an integer multiple of the ratio of the first chip rate to the second chip rate, or an odd multiple of one-half the ratio of the first chip rate to the second chip rate.
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8. A method for transmitting data, comprising:
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encoding a first data stream using a first code to produce a first encoded data stream;
modulating the first encoded data stream to produce a first data signal having a first bandwidth in a frequency spectrum;encoding a second data stream using a spreading code to produce a spread signal, the spread signal having a second bandwidth in the frequency spectrum, wherein the spreading code is orthogonal to the first code; encoding a third data stream using a third code to produce a third encoded data stream; modulating the third encoded data stream to produce a third data signal having the first bandwidth in the frequency spectrum, wherein the spreading code is orthogonal to the third code; and simultaneously transmitting the first data signal and the spread signal, wherein the spread signal overlays the first data signal in the frequency spectrum. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A system for transmitting data, comprising:
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an encoder configured to encode a first data stream using at least one code to produce at least one encoded data stream; a modulator configured to modulate the at least one encoded data stream to produce a first signal having a first bandwidth; and a transmitter configured to simultaneously transmit the first signal and a plurality of second signals, wherein the first signal overlays the plurality of second signals in a frequency spectrum and the first signal is orthogonal to each of the plurality of second signals. - View Dependent Claims (15, 16, 17, 18)
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19. A method for transmitting data, comprising:
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encoding a first data stream using at least one Walsh code to produce a first encoded data stream; modulating the first encoded data stream to produce a first data signal having a first bandwidth in a frequency spectrum; and simultaneously transmitting the first data signal with a plurality of second signals, the plurality of second signals representing narrow-band signals, wherein the first data signal overlays the plurality of second signals in the frequency spectrum and is orthogonal to each of the plurality of second signals. - View Dependent Claims (20, 21, 22)
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Specification