| 摘要 |
A communication system is used to transmit and receive 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 spreaded signal, and a control data 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. Further, if the length of the message intended for transmission by the wideband transceivers is below a message length threshold, the message can be transmitted using a common access channel shared by the wideband transceivers. Still further, by adapting the data transmission rate, in response to the data error rate and transmitter power level, the transmission range and/or the data transmission rate can be optimized.
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