Receiver and method for receiving spread frequency signal by estimating transmitting symbol rate

Abstract

In a spread spectrum receiver, a first despread signal is produced by a despreading circuit corresponding to a first symbol rate. The despreading circuit is responsive to a command signal for subsequently producing a second despread signal corresponding to the second symbol rate. A symbol rate estimation circuit is provided for estimating, from the first despread signal, the transmitted symbol rate of the spread spectrum signal as one of the first and second symbol rates. If the transmitted symbol rate is estimated as the first symbol rate, the despreading circuit continues producing the first despread signal. If the transmitted symbol rate is estimated as the second symbol rate, the estimation circuit supplies the command signal to the despreading circuit to produce the second despread signal. A decoding circuit decodes the first and second despread signals.

Description

technical field [0001] The present invention generally relates to CDMA (Code Division Multiple Access) receivers and CDMA receiving methods. In particular, the present invention relates to a CDMA receiver using concealed rate transmission and to pseudorandom noise (PN) formed in a layered sequence for spreading at the transmitting end and despreading at the receiving end code. Background technique [0002] In a spread spectrum communication channel, receiving and demodulating a signal that has been spread spectrum modulated requires the same pseudorandom noise (PN) code sequence generated in the receiver and correlated with the received signal in order to extract the data Code element value. These PN code sequences are hierarchically constructed so that a PN code sequence corresponding to a low symbol rate can be determined from a PN code sequence corresponding to a high symbol rate. The spread spectrum signal is transmitted at a symbol rate selected from a predetermined ...

AI Technical Summary

Problems solved by technology

Since the decoding process is usually provided by a complex forward error correction (FEC) decoder, the frequent attempts to decode the spread spectrum signal place a significant load on the FEC decoder, resulting in significant losses in terms of both decoding time and power consumption. have increased

This is a significant disadvantage of mobile spread spectrum receivers

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