JPH1141137A - Receiving device for spread spectrum communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it unnecessary to transmit a pilot symbol in addition to a start symbol for estimating propagation path characteristics, and to efficiently estimate the characteristics by operating envelope detection separately from the delay detection of an inverse spread signal, and estimating the propagation characteristics according to the detected result. SOLUTION: A start symbol spread spectrum by one spreading code is transmitted prior to signals (data symbol) transmitted in parallel. At the time of receiving the start symbol, orthogonal I signal and Q signal are inputted to passive correctors 10 and 11, and a correlation value is outputted from the passive correlator 10 matched with the spreading code of a transmission channel. The output signal of the passive correlator 10 is supplied to a delay detector 20, and also supplied to a delay detector 21 according to the switching of switches 1 and 2. The output signal of the passive corrector 10 is also inputted to an envelope detector 70, and envelop detection is operated. Then, an outputted envelope signal is supplied to a propagation path estimator 40, and used for estimating propagation characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectrum in which transmission data is converted into a plurality of data sequences in parallel and differentially encoded, and the obtained differentially encoded data sequences are transmitted in parallel using a plurality of different spreading codes. Used for spread communication. In particular, the present invention relates to a spread spectrum communication receiver for estimating a propagation path characteristic and demodulating a transmitted signal.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional receiver for spread spectrum communication. The receiving apparatus for spread spectrum communication comprises passive correlators 10 and 11 for despreading signals spread in parallel using different spreading codes and transmitted in parallel, respectively.
Delay detectors 20 and 21 for delay-detecting the output signals 0 and 11; diversity combiners 30 and 31 for diversity-combining the respective detection outputs of the delay detectors 20 and 21; A propagation path estimator 40 that estimates propagation path characteristics from the detection output and supplies the propagation path characteristics to the diversity combiners 30 and 31, and a diversity combiner 30, 3
1 for decoding transmission data from the output of
0 and 51 and switches 1 and 2 for selecting one of the outputs of the passive correlators 10 and 11 and connecting to the differential detector 21
Switches 3 and 4 for connecting the output of the delay detector 20 to the diversity combiner 30 or the propagation path estimator 40, and a switch 5 for turning on and off the connection between the output of the delay detector 21 and the diversity combiner 31; 6 and a switch controller 60 for controlling the switches 1 to 6.

In order to perform propagation path estimation, prior to parallel transmission of differentially encoded data sequences, a start symbol and a pilot symbol are spread with only one spreading code and transmitted. When such a transmission signal is received by the receiver for spread spectrum communication, the orthogonal I
The signal and the Q signal are applied to the passive correlator 10 and the passive correlator 1
1 and the correlation value is output from the passive correlator 10 matched to the spreading code of the transmission channel. At this time, the output signal of the passive correlator 10 is supplied to the delay detector 20 and also supplied to the delay detector 21 by switching the switches 1 and 2 by the switch controller 60. Each of the differential detectors 20 and 21 performs differential detection from a start symbol of one symbol and a pilot symbol of one symbol, and outputs a pilot signal. The pilot signal output from the differential detector 20 is a switch 3,
4 is switched by the switch controller 60 to be supplied to the propagation path estimator 40 and used for estimating propagation path characteristics. The output of the passive correlator 10 is supplied to the delay detector 21 in order to delay-detect a data symbol following the pilot symbol, and the output of the delay detector 21 at this point is unnecessary. Therefore, the switches 5 and 6 are switched by the switch controller 60 to disconnect the connection between the delay detector 21 and the diversity combiner 31.

At the time of data symbol transmission, parallel transmission is performed. When such a transmission signal is received by a receiver for spread spectrum communication, orthogonal I and Q signals are input to passive correlators 10 and 11, and a correlation value matched to a spread code of each transmission channel is converted to a passive correlation value. Output from the devices 10 and 11, respectively. At the same time, the passive correlator 1 is switched by switching the switches 1 and 2 by the switch controller 60.
1 is input to the differential detector 21. As a result, the delay detectors 20 and 21 are respectively connected to the passive correlator 1
The outputs 0 and 11 are differentially detected for each period of the spreading code. The output signal of the delay detector 20 is supplied to the diversity combiner 30 by switching the switches 3 and 4 by the switch controller 60. The output signal of the delay detector 21 is supplied to the diversity combiner 31 by switching the switches 5 and 6 by the switch controller 60. Diversity combiners 30 and 31 perform diversity combining using the estimated values of the channel characteristics output from channel estimator 40, respectively. Output signals of the diversity combiners 30 and 31 are input to decoders 50 and 51, respectively, where data is decoded.

[0005]

However, in the prior art, a pilot symbol is required in addition to the start symbol to estimate the propagation path characteristics, and the data transmission efficiency is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a spread spectrum communication receiver capable of efficiently estimating propagation path characteristics and improving data transmission efficiency.

[0007]

A receiving apparatus for spread spectrum communication according to the present invention comprises a plurality of despreading means for despreading signals spread in parallel using different spreading codes and transmitted in parallel, respectively. A plurality of delay detection means for delay detection of each output signal of the despreading means, and a propagation path characteristic estimation means for estimating a propagation path characteristic from a detection output for one output signal of the plurality of despreading means,
Processing means for processing the output signals of the plurality of delay detection means based on the propagation path characteristics estimated by the propagation path characteristic estimation means, wherein the plurality of delay detection means Separately, there is provided an envelope detection means for performing envelope detection on the one output signal and supplying the detected output to the propagation path characteristic estimating means.

In the present invention, since the differential detection signal is not used for estimating the channel characteristics, the channel characteristics can be estimated from one symbol. Therefore, when the transmission side transmits a start symbol that is spread with one spreading code prior to the parallel signal,
The propagation path characteristic estimating means can estimate the propagation path characteristic from the output of the envelope detection means for the start symbol. In this case, no pilot symbol is needed,
Data transmission efficiency can be improved.

[0009] As a parallel signal that is spread and transmitted, a differentially encoded data sequence obtained by converting transmission data into a plurality of data sequences in parallel and differentially encoding the same can be used.

[0010]

FIG. 1 is a block diagram showing an embodiment of the present invention. The receiving apparatus for spread spectrum communication according to this embodiment includes a plurality of passive correlators 10 and 11 for despreading signals spread in parallel using different spreading codes and transmitted in parallel, respectively. 11, a delay detector 20, 21 for delay detection of each output signal, a propagation path estimator 40 for estimating a propagation path characteristic from a detection output of one output signal of the passive correlator 10, 11; Diversity combiner 3 that diversity-combines the output signals of delay detectors 20 and 21 based on the propagation path characteristics estimated by estimator 40.
0, 31 and decoders 50, 51 for decoding data from the outputs of the diversity combiners 30, 31;
Further, separately from the delay detectors 20 and 21, the passive correlator 1
An envelope detector 70 for performing envelope detection on one of the output signals 0 and 11 and supplying the detected output to the propagation path estimator 40 is provided. A switch 1 for selecting one of the outputs of the passive correlators 10 and 11 and connecting the selected output to the delay detector 21;
2, switches 7 and 8 for turning on and off the connection between the envelope detector 70 and the propagation path estimator 40, and a switch controller 60 for controlling the switches 1, 2, 7 and 8.

A signal received by the receiver for spread spectrum communication according to this embodiment is converted into a plurality of data sequences after transmission data is differentially encoded, and these differentially encoded data sequences are converted into a plurality of different spread codes. Is a signal transmitted in parallel using. Signals (data symbols) transmitted in parallel
Prior to this, a start symbol that is spread with one spreading code is transmitted.

When a start symbol is received, the orthogonal I
The signal and the Q signal are applied to the passive correlator 10 and the passive correlator 1
1 and the correlation value is output from the passive correlator 10 matched to the spreading code of the transmission channel. The output signal of the passive correlator 10 is supplied to the delay detector 20 and also supplied to the delay detector 21 by switching the switches 1 and 2 by the switch controller 60. Passive correlator 1
The output signal of 0 is also input to the envelope detector 70,
Envelope detection is performed. The envelope signal output from the envelope detector 70 switches the switches 7 and 8 to the switch controller 60.
Is supplied to the channel estimator 40 and used for estimating channel characteristics.

At the time of data symbol reception, orthogonal I and Q signals are input to passive correlators 10 and 11, and correlation values matched with spreading codes of respective transmission channels are output from passive correlators 10 and 11, respectively. At the same time, by switching the switches 1 and 2 by the switch controller 60, the output signal from the passive correlator 11 is input to the differential detector 21. As a result, the delay detectors 20 and 21 perform delay detection of the outputs of the passive correlators 10 and 11 for each period of the spreading code. Output signals of the differential detectors 20 and 21 are supplied to diversity combiners 30 and 31, respectively. Diversity combiners 30 and 31 each include a propagation path estimator 4
Diversity combining is performed using the estimated values of the propagation path characteristics output by 0. Output signals of the diversity combiners 30 and 31 are input to decoders 50 and 51, respectively, where data is decoded.

In this embodiment, the envelope detector 70 operates even when receiving data symbols. However, the output envelope signal causes switches 7 and 8 to
Is not input to the propagation path estimator 40. The configuration of this embodiment can be changed to stop the operation of the envelope detector 70 at the time of receiving data symbols.

As the passive correlators 10 and 11, a matched filter or a convolver can be used.

[0016]

As described above, according to the present invention, the envelope detection is performed separately from the delay detection of the despread signal, and the propagation path characteristics are estimated based on the detection result. This allows
There is no need to transmit a pilot symbol in addition to the start symbol for estimating the propagation path characteristics, and there is an effect that the propagation path characteristics can be efficiently estimated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional spread spectrum communication receiver.

[Explanation of symbols]

 1-8 Switch 10,11 Passive correlator 20,21 Delay detector 30,31 Diversity combiner 40 Propagation path estimator 50,51 Decoder 60 Switch controller 70 Envelope detector

Claims (3)

[Claims] 1. A plurality of despreading means for respectively despreading a signal spread in a spectrum and transmitted in parallel using different spreading codes, and a plurality of delays for delay-detecting output signals of the plurality of despreading means. Detecting means, a propagation path characteristic estimating means for estimating a propagation path characteristic from a detection output of one output signal of the plurality of despreading means, and based on the propagation path characteristic estimated by the propagation path characteristic estimating means, In a receiving apparatus for spread spectrum communication, comprising: a processing unit that processes output signals of a plurality of delay detection units, separately from the plurality of delay detection units, the one output signal is envelope-detected, and a detection output thereof is output. A receiving apparatus for spread spectrum communication, comprising: an envelope detecting means for supplying to the propagation path characteristic estimating means. 2. A transmitting side transmits a start symbol spectrum-spread with one spreading code prior to a parallel signal, and the propagation path characteristic estimating means outputs a propagation signal based on an output of the envelope detection means for the start symbol. The receiving apparatus for spread spectrum communication according to claim 1, wherein the characteristic is estimated. 3. The parallel signal transmitted by spread spectrum transmission is a differentially encoded data sequence obtained by converting transmission data into a plurality of data sequences in parallel and differentially encoding the data sequence. Receiver for spread spectrum communication.