WO2001052435A1

WO2001052435A1 - Spread spectrum receiver

Info

Publication number: WO2001052435A1
Application number: PCT/JP2001/000056
Authority: WO
Inventors: Yoshiki Mamori
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2000-01-11
Filing date: 2001-01-10
Publication date: 2001-07-19
Also published as: AU5790201A; JP2001196971A

Abstract

A spread spectrum receiver the circuit scale of which is reduced by reducing the number of despreading sections. The spread spectrum receiver comprises a section (101) for decimating received signals (RxI, RxQ) with an on-time clock (OTCLK), a section (102) for delivering the decimated signals (OTI, OTQ) from the decimating section (101) to a data latch section (104), a selector section (103) for switching PN sequence codes (PnWI, PnWQ) delivered to the despreading section (102) and supplying a select signal (Sel[n:1]) to the data latch section (104), the data latch section (104) for latching despread signals (DOTI, DOTQ) from the despreading section (102) for each select signal (Sel[n:1]) from the selector section (103), and n data path demodulating sections (1051-105n) for demodulating the signal latched in the data latch section (104).

Description

Description Spread spectrum receiver Technical field

The present invention relates to a spread spectrum receiver, and more particularly to a spread spectrum receiver that demodulates a large amount of data and reduces the circuit scale by reducing the number of despreading units. . Background art

In recent years, communication devices using a spread spectrum (SS) method as a digital modulation and demodulation method have been proposed. The spread spectrum method is a method of transmitting a signal using a signal (a spread spectrum) that has been significantly broadened compared to the information transmission rate by a code or a signal irrelevant to information. Demodulation is performed after narrowing the band (reverse spreading).

On the other hand, in mobile communication technologies such as mobile phones, the Code Division Multiple Access (CD MA) communication system, which has advantages such as high communication capacity, confidentiality of communication data, and excellent interference resistance, attracts attention. Have been. In such a mobile phone of the CDMA type (referred to as a CDMA mobile phone), a typical configuration of a receiving system is a configuration having a rake receiver in the receiving system. The rake receiver has a plurality of finger circuits in it, extracts symbol signals for each system, and combines a plurality of identical signal components in a symbol combining circuit to improve communication quality.

In particular, recently, in order to demodulate a large amount of communication data, a configuration in which a finger circuit includes a plurality of despreading units and a data path demodulation unit has been proposed. FIG. 3 shows a configuration diagram of a thinning unit, a despreading unit, and a data demodulation unit in a conventional spread spectrum receiver having a finger circuit for demodulating a large amount of data.

In the figure, the finger circuit of the conventional spread spectrum receiver has one decimation unit 301, and n despreading units 3102-10302η from the first to the n-th. The first And n data path demodulators 3051 to 305 n.

The operation of the conventional spread spectrum receiver will be described with reference to FIG. FIG. 4 is a timing chart illustrating the operation of a finger circuit of a conventional spread spectrum receiver.

First, the decimation unit 301 decimates the reception signals Rxl and RxQ shown in FIG. 4C using the on-time clock OTCLK as shown in FIG. 4B, and decimates the reception signals OTCLK as shown in FIG. 4D. I and OTQ are generated and output to the first to n-th despreading units 3021 to 302n. Here, the on-time clock 0 TCLK is generated based on a clock as shown in FIG.

As shown in FIG. 4 (e), the first despreading unit 3021 performs despreading with the thinned-out signal OTI: OTQ and the PN sequence codes PnWI [1] and PnWQ [1], and outputs the despread signal DO TI [ 1] and D◦ TQ [1] are output to the first data path demodulation unit 3051.

Also, as shown in FIG. 4 (f), the second despreading section 3022 performs despreading with the thinned-out signals OTI and OTQ and the PN sequence codes PnWI [2] and PnWQ [2], and outputs the despread signal DOT I [2] and DOTQ [2] are output to the second data path demodulation unit 3052.

Similarly, in the (n−1) th despreading unit 302 n−1, as shown in FIG. 4 (g), the decimation signals OTI and OTQ and the PN sequence codes PnWI [n−1] and PnW Q [ n-1], and outputs despread signals DOT I [n-1] and DOTQ [n-1] to the (n-1) th overnight demodulator 305 n-1.

Similarly, in the n-th despreading unit 302 n, as shown in FIG. 4 (h), despreading is performed using the decimation signals 0TI and OTQ and the PN sequence codes PnWI [n] and PnWQ [n], and despreading is performed. The spread signals DOT I [n] and DOTQ [n] are output to the n-th data path demodulator 302 n.

Thus, in the above conventional spread spectrum receiver, in order to demodulate a large amount of data, the number of despreading units and data demodulating units in the finger circuit should be increased. However, as the amount of data increases, the number of despreading units and data demodulation units in the finger circuit increases, which leads to an increase in the circuit scale of the entire spread spectrum receiver. there were.

The present invention has been made in view of the above-mentioned conventional circumstances, and in a spectrum spreading receiver for demodulating a large amount of data, the number of despreading units in a finger circuit is reduced to reduce the circuit scale. The purpose is to provide a small spread spectrum receiver. Disclosure of the invention

In order to solve the above problem, a spread spectrum receiver according to the present invention includes: a thinning unit that samples a received signal at a predetermined thinning timing; a selector unit that selects a spread signal based on a predetermined selection signal; A despreading unit for despreading the signal sampled by the decimation unit by a correlation operation with the spread signal selected by the selector unit; and selectively despreading the signal despread by the despreading unit based on the selection signal. A data latch for latching the data; and a plurality of data path demodulators for individually demodulating the signals selectively latched by the data latch.

In the spread spectrum receiver, the spread signal is a PN sequence code.

In the spread spectrum receiver of the present invention, the received signal is sampled at a predetermined decimation timing by the decimation unit, and the signal sampled by the decimation unit is demultiplexed by the despreading unit at the selector unit based on a predetermined selection signal. The despread signal is despread by a correlation operation with the selected spread signal, and the despread signal is selectively latched in a data latch section based on the selection signal. The selectively latched signals are individually demodulated.

In other words, in the conventional spread spectrum receiver, the finger circuit is composed of one decimation unit, n despreading units from 1 to n, and n data path demodulation from 1 to n. In contrast, in the spread spectrum receiver of the present invention, the number of demodulation path demodulation units is n, the number of decimation units is 1, and the number of despreading units is 1. One selector for switching the spread signal to be supplied to the despreading unit, one de-latching unit for latching the despread signal despread by the despreading unit, and the signal latched by the data latch unit. By constructing a finger circuit with n data path demodulators for demodulation, the same function as in the past can be realized, so the number of inverse spread parts in the finger circuit is reduced and the circuit scale is reduced Thus, it is possible to realize a spread spectrum receiver.

In the spread spectrum receiver, it is preferable that the spread signal is a PN sequence code. Note that “PN sequence code” refers to “broadly-defined PN sequence code” and includes various code sequences such as an M sequence and a Go 1d sequence. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a configuration diagram of a spread spectrum receiver according to one embodiment of the present invention. FIG. 2 is an evening chart illustrating the operation of the finger circuit of the spread spectrum receiver according to the embodiment.

FIG. 3 is a configuration diagram of a thinning unit, a despreading unit, and a data demodulation unit in a conventional spread spectrum receiver having a finger circuit.

FIG. 4 is a timing chart for explaining the operation of a finger circuit of a conventional spread spectrum receiver. In addition, the code in the figure, 101 is a decimation unit, 102 is a despreading unit, 103 is a selector unit, 104 is a data latch unit, 105 1 to 105 n are a data path demodulation unit, RxI and RxQ are received signals, OTCLK is an on-time clock, OTI, 〇TQ is a thinning signal, S el [n: 1] is a selection signal, PnWI and PnWQ are PN sequence codes, PnWI [n: 1] and PnWQ [n: 1] are PN sequences DOT I and D 0 TQ are despread signals, DOT I [n: 1] and DOTQ [n: 1] are despread signals, 301 is a decimation unit, 3021 to 302 n are despread units, and 3051 to 305 n Is a data path demodulator. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the spread spectrum receiver of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram of a spread spectrum receiver according to one embodiment of the present invention. The spread spectrum receiver according to the present embodiment employs a quaternary phase modulation (QPSK) as a modulation method, and each element includes an in-phase component and a quadrature component. Will be subjected to signal processing. Further, when the configuration of the embodiment is applied to a rake receiver, it is configured in each finger circuit of the rake receiver. Also, a PN sequence code is used as the spread signal.

In other words, the configuration of FIG. 1 shows a configuration centering on the thinning unit, despreading unit and data path demodulation unit in the spread spectrum receiver. In FIG. Decimation section 101, one despreading section 102, one selector section 103, one data latch section 104, and n data path demodulations from the first to the nth This is a configuration including the units 1051 to 105n. As a configuration of the reception system of the spread spectrum receiver, for example, an antenna, an analog front end, an A / D conversion unit, and the like are configured in front of the decimation unit 101 in FIG. In the subsequent stage of the n data path demodulators 1051 to 105n, for example, a symbol combining circuit, a din / leave circuit, and a video decoding circuit are configured. The decimating unit 101 is supplied from the evening timing control unit (not shown) with respect to the received signal Rxl of the same phase (I phase) as the carrier received via an antenna (not shown) and the received signal RxQ of the quadrature phase (Q phase) with the carrier. Thinning (sampling) is performed at the timing of the on-time clock OT CLK.

Further, the selector unit 103 selects the 1 ^ sequence code 卩 11 ^ 1 [n: 1], P nWQ [n: 1] based on the selection signal Se l [n: 1], and outputs the PN sequence code PnW I, P nWQ is selectively output. Here, PnWI [n: 1], PnWQ [n: 1] and Se1 [n: 1] are signals having an n-bit width. The decimated signals 〇 TI and OTQ decimated by the decimation section 101 are converted into , A despreading is performed by a correlation operation with a PN sequence code Pn WI, PnWQ as a spread signal supplied from the selector section 103, and outputs despread signals DOT I, DOTQ as correlation value data and outputs the data latch section 104. To supply.

Further, the data latch section 104 selectively latches the despread signal DOTI _; DOTQ from the despread section 102 based on the selection signal Se1 [n: 1]. In addition,

The n data path demodulators 1051 to 105n from 1 to n individually demodulate the signals selectively latched by the data latch 104.

Next, the operation of the spread spectrum receiver according to the present embodiment having the above configuration will be described with reference to FIG. FIG. 2 is a timing chart illustrating the operation of the finger circuit of the spread spectrum receiver according to the present embodiment. In the same figure, FIG. 2 (a) is a clock, FIG. 2 (b) is an on-time clock 〇 TCLK, FIG. 2 (c) is a received signal Rxl, RxQ, FIG. 2 (d) is a thinned signal OTI, OTQ, Fig. 2 (e) to Fig. 2

(h) is the selection signal Se 1 [n: 1], and Fig. 2 (i) is the PN sequence code PnWI [n:

1], PnWQ [n: 1], and FIG. 2 (j) shows the despread signals DOT I [n: 1] and DO TQ [n: 1] respectively.

First, the decimation unit 301 decimates the received signals RxI and RxQ shown in FIG. 2 (c) using the on-time clock ΔT CLK as shown in FIG. 2 (b), and as shown in FIG. 2 (d). The thinning signals OT I and OTQ are output to the despreading unit 102. Here, the on-time clock OTCLK is generated by a timing control unit (not shown) based on a clock as shown in FIG.

The selector 103 has a selection signal Se 1 as shown in FIGS. 2 (e) to 2 (h).

[n: 1] is supplied, and the PN sequence codes PnWI [n: 1] and PnWQ [n: 1] are selected based on the selection signal Se 1 [n: 1]. The selection operation is specifically as shown in FIG. 2 (i). When the selection signal Se 1 [1] is active, the PN sequence codes PnWI [1] and PnWQ [1] are selected, and the selection signal S e 1

When [2] is active, the PN sequence codes PnWI [2] and PnWQ [2] are selected. Similarly, when the selection signal Sel [n-1] is active, the PN sequence codes PnWI [n-1], PnWQ [n— 1] is selected and the selection signal S e 1 [n] is When active, the PN sequence codes PnWI [n] and PnWQ [n] are selected. Next, the despreading unit 102 performs despreading on the decimation signals OTI and OTQ decimated by the decimation unit 101 by performing a correlation operation with the PN sequence codes P nW I and PnWQ selected and output by the selector unit 103, and The despread signals DO TI and DOTQ are output to the data latch 104 as data. Further, the data latch unit 104 selectively latches the despread signal DOT I, 00,00 based on the selection signal 361 [n: 1], and furthermore, the n-th number from the first to the n-th. The data-pass demodulators 1051 to 105n individually demodulate the signals selectively latched by the data latch 104.

More specifically, as shown in FIG. 2 (j), the despreading section 102 performs a despread signal D 0 TI [1], DOTQ by performing a correlation operation with the PN sequence codes PnWI [1] and PnWQ [1]. When [1] is generated, the data latch unit 104 selects the selection signal S e 1

According to [1], the despread signals DOT I [1] and DOTQ [1] are output to the first demodulator path demodulator 1051 and demodulated. Despreading section 102 performs a despread signal D 0 T I by performing a correlation operation with PN sequence codes PnWI [2] and PnWQ [2].

When [2] and DOTQ [2] are generated, the data latch section 104 demodulates the despread signals DOT I [2] and DOTQ [2] into the second data path according to the selection signal S e 1 [2]. The signal is output to the unit 1052 and demodulated.

Similarly, despreading section 102 generates despread signals DOT I [n-1] and DOTQ [η-1] by performing a correlation operation with PN sequence codes PnWI [n-1] and PnW Q [n-1]. Then, in the data latch unit 104, the despread signals DOT I [n−1] and DOTQ [n−1] are converted to the n−1 th data path demodulation unit by the selection signal Se 1 [n−1]. It is output to 105 n_1 and demodulated. Further, in despreading section 102, when despread signals DOT I [n] and DOTQ [n] are generated by a correlation operation with PN sequence codes PnWI [n] and PnWQ [n], data latch section At 104, the despread signals DOT I [n] and DOTQ [n] are output to the n-th data path demodulation unit 105 n according to the selection signal S e 1 [n] and demodulated.

As described above, in the spread spectrum receiver of the present embodiment, the data in the finger circuit is used. The number of the overnight path demodulators is the same as the conventional one, with one despreader (101) and one selector for switching the PN sequence code PnWI and PnWQ to be supplied to the despreader 101 (103) The despread signal DOT I, D • TQ despread by the despreading unit 102 is latched for each selection signal S e1 supplied from the selector unit 103. One data latch unit (104) The data path demodulation unit that demodulates the signal latched by the evening latch unit 104 is realized with n (1051 to 105n) configurations.

The thinning section 101 samples the received signals RxI and RxQ with the on-time clock 0TCLK, and the selector section 103 selects the PN sequence codes PnWI [n: 1] and PnWQ [n: 1] as selection signals Sel [n: 1], and the despreading unit 102 performs despreading with the decimation signals OT I and OT Q sampled by the decimation unit 101 and the PN sequence codes PnWI and P nWQ from the selection unit 103 to obtain the despread signal DOT. I, DOTQ are supplied to the data latch section 104, and the data latch section 104 selectively latches the despread signals DOT I, DOTQ based on the selection signal Se l [n: 1]. The n data path demodulation sections 1051 to 105 n up to now individually demodulate the signals selectively latched by the data latch section 104, thereby realizing the same functions as in the past. As a result, the number of despreading units in the finger circuit of the spread spectrum receiver can be reduced, and a spectrum spread receiver with a smaller circuit scale can be realized. In particular, rake receivers have multiple finger circuits in them, so the effect of circuit size reduction is significant.

As described above, according to the spread spectrum receiver of the present invention, the number of demodulation path demodulators is n (n is a positive integer), the same number as in the past, the number of decimation sections is 1, and the despreading section is despread. 1 unit, 1 selector unit to switch the spread signal supplied to the despreading unit, 1 data latch unit to latch the despread signal despread by the despreading unit, and the signal latched by the data latch unit The demodulation path demodulator that demodulates each By configuring the circuit, the same function as in the past can be realized, so that the number of despreading units in the finger circuit can be reduced and a spectrum spreading receiver with a smaller circuit size can be provided. .

Claims

The scope of the claims

1. Thinning means for sampling a received signal at a predetermined thinning timing, a selector unit for selecting a spread signal based on a predetermined selection signal,

A despreading unit for despreading the signal sampled by the thinning unit by performing a correlation operation with a spread signal selected by the selector unit;

A data latch unit that selectively latches the signal despread by the despreading unit based on the selection signal;

A plurality of data path demodulators for individually demodulating the signals selectively latched by the data latch,

A spread spectrum receiver comprising:

2. The spectrum spread receiver according to claim 1, wherein the spread signal is a PN sequence code.