JP2013005387A - Despread device for spread spectrum communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a despread device for spread spectrum communication, capable of achieving demodulation processing of different radio systems with an identical circuit for circuit sharing in a communication apparatus using such different radio systems.SOLUTION: A despread device 13 for spread spectrum communication includes: code generation means 20-1 to 20-N capable of outputting any of spread codes of two or more different code systems, correlation means 21-1 to 21-N that generate correlation values 27-1 to 27-N between spread codes and reception signals generated by the code generation means; and back diffusion means that outputs correlation values.

Description

  The present invention relates to a direct spectrum spread signal demodulating apparatus, and more particularly to a spread spectrum communication despreading apparatus capable of demodulating a CCK (Complementary Code Keying) signal.

  In recent years, in the field of wireless communication, devices capable of communicating with different wireless systems have been developed. For example, there is an example of a mobile terminal device that can support both a third generation mobile phone system (3G system) and a wireless LAN represented by IEEE 802.11. Note that 3G means 3rd. Abbreviation for Generation. IEEE is an abbreviation for The Institute of Electrical and Electronic Engineers. Further, the wireless LAN is an abbreviation for wireless local area network.

  In the 3G system, a modulation scheme called CDMA (Code Division Multiple Access) that multiplexes signals by DSSS using a plurality of codes is used. Regarding this CDMA, for example, Patent Document 1 discloses a rake receiver as one of the demodulation means.

  IEEE802.11b uses a direct sequence spread spectrum (DSSS) modulation scheme and a modulation scheme called CCK (Complementary Code Keying) based on DSSS. This CCK is disclosed in Patent Document 2, for example.

  In order to process signals of these different wireless standards by one communication device, the communication device needs to support both of these different wireless standards. For example, in Patent Document 3, a communication unit corresponding to both of a plurality of wireless standards is separately provided in one communication device, and switching to another wireless standard is performed according to the wireless standard used for communication. A possible terminal device is disclosed.

  In the example of Patent Document 3, two standards, W-CDMA and wireless LAN, are used as a plurality of wireless standards. W-CDMA is an abbreviation for Wideband Code Division Multiple Access. Therefore, a CDMA demodulation process used in the W-CDMA standard and a CCK demodulation process used in the wireless LAN standard will be described below.

  FIG. 7 shows a configuration of a CDMA despreading unit 110 that is a related technique.

  The code generation unit 111 generates the same spreading code as the spreading code used on the transmission side, and outputs it to the correlation unit 112. The correlation unit 112 generates a correlation value between the input received signal and the spread code and outputs it as a correlation value 113.

  The despreading unit 110, in particular, the correlation units 112-1 to 112-M will be described in detail. A signal multiplexed with a plurality of different spread codes (M) as a received signal is input to correlation section 112-1. The code generator 111-1 generates the first spreading code among the M spreading codes and outputs it to the correlator 112-1.

  Correlator 112-1 despreads the received signal with the first spreading code to generate correlation value 113-1. Correlation section 112-2 generates correlation value 113-2 using the second spreading code of M spreading codes given from code generation section 111-2. Similarly, the correlation unit 112-M generates a correlation value 113-M using the Mth spreading code given from the code generation unit 111-M. In this way, a signal obtained by demodulating M transmission signals before being multiplexed is obtained from all M correlation values 113.

  Next, a CCK demodulator using a fast Walsh transform (FWT) that is a related technique will be described. As prior knowledge, an outline of the CCK modulation method and its demodulation method in 802.11b will be described.

  In CCK modulation in 802.11b, 8 bits (d0, d1,..., D7 from the beginning) of the signal before modulation are divided into 4 groups each having 2 bits, and [d0, d1] is converted to DQPSK (Differential Quadrature Phase shift keying) is mapped to the signal point arrangement, and [d2, d3], [d4, d5], and [d6, d7] are mapped to the signal point arrangement of QPSK. Assuming that the phase of the signal point at which each is arranged is φ1, φ2, φ3, φ4, CCK modulation uses the following formula (d0, d1, φ3, φ4 for signals d0, d1,..., D7: The signal is modulated by the CCK code word of 1).

・・・式（１）
ここで、式（１）から

... Formula (1)
Here, from equation (1)

If you start and transform,

・・・式（２）
となる。

... Formula (2)
It becomes.

  FIG. 8 shows the configuration of a CCK demodulator using a fast Walsh transform (FWT). The FWT calculator 120 generates correlation values between the received signal and 64 types of CCK code words by high-speed Walsh transform.

  First, the received signal is serially input to the serial / parallel (S / P) converter 121. Thereafter, serial received signals are rearranged in parallel by the S / P converter 121 and input to BFWBs 122-1 to 122-4, which are basic fast Walsh transform blocks (BFWB).

  The BFWBs 122-1 to 122-4 generate correlation values ψ1 to ψ64 from the parallel signal input from the S / P converter 121 by high-speed Walsh transform. Thereafter, the correlation values ψ1 to ψ64 from the BFWB 122-1 to -4 are input to the maximum value search unit 123, and the maximum value search unit 123 selects a correlation value having the maximum value from the correlation values ψ1 to ψ64. Output. At the same time, the phase components φ2, φ3, and φ4 (described later) of the CCK code word that generates the maximum correlation value ψ ′ are also output.

  The operation of the FWT calculation unit 120, particularly the operations of the BFWBs 122-1 to 122-4, will be described in more detail. The received signals input to the FWT calculation unit 120 are rearranged into parallel signals in units of 8 chips by the S / P conversion unit 121 and input to the BFWBs 122-1 to 4.

  Each BFWB 122-1-4 uses three phase components (φ2, φ3, φ4) each having four types of rotation amounts (0, π / 2, π, 3π / 2) used for CCK codeword generation. The correlation value is generated as follows. That is, in BFWB 122-1, φ2 = 0 is fixed, and 4 × 4 = 16 types of correlation values are generated for each of φ3 and φ4. Similarly, BFWB 122-2 is fixed to φ2 = π / 2, BFWB 122-3 is fixed to φ2 = π, and BFWB 122-4 is fixed to φ2 = 3π / 2, each generating 16 types of correlation values. To do. In this way, correlation values ψ1 to ψ64 between the received signal and 16 × 4 = 64 types of CCK code words are generated.

  The maximum value search unit 123 selects a CCK code word having the highest correlation. Therefore, the maximum correlation value ψ ′ is selected from the correlation values ψ1 to ψ64 and output. At the same time, phase components φ2, φ3, and φ4 that generate ψ ′ are output.

  Based on φ2, φ3, and φ4 obtained in this way, φ1 can be obtained by despreading C based on the equation (2). Since φ1 is a DQPSK signal, the signal can be decoded by a general DQPSK signal demodulation method.

JP 2001-223611 A Japanese Patent Laid-Open No. 2006-217024 JP 2005-136553 A

  However, the techniques of Patent Document 1 and Patent Document 2 each include a CDMA or CCK demodulation process alone, and can perform only one of these processes. The technique of Patent Document 3 includes both a WCDMA processing unit and a wireless LAN processing unit, but only includes two communication processing units having different wireless standards.

  Therefore, the technology of Patent Technology 3 has a problem that the circuit scale increases. Moreover, since the communication unit of the other wireless standard is not used while one of the wireless standards is used, there is a problem that the circuit utilization efficiency is poor.

  An object of the present invention is to provide a spread spectrum communication despreading device that enables demodulation of different wireless methods in the same circuit in a communication device using different wireless methods, and enables circuit sharing. To do.

  A despreading apparatus for spread spectrum communication according to the present invention includes a code generator capable of outputting any one of two or more different code schemes, and a correlation value between a spread code output from the code generator and a received signal. And a despreading means for outputting the correlation value.

The despreading method of spread spectrum communication according to the present invention outputs any one of two or more different spreading codes and generates a correlation value between the outputted spreading code and a received signal.
The correlation value is output.

  By adopting the configuration as described above, the present invention realizes the spread spectrum communication in which communication processing using different wireless systems realizes demodulation processing of different wireless systems with the same circuit and enables circuit sharing. A despreading device can be provided.

It is a block diagram which shows the structural example of the spread spectrum communication receiver in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the de-spreading part of the de-spreading apparatus of the spread spectrum communication in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the multiple code generator of the de-spreading apparatus of the spread spectrum communication in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the spread spectrum communication receiver in the 2nd Embodiment of this invention. It is a block diagram which shows the structural example of the rake receiving part of the spread spectrum communication in the 2nd Embodiment of this invention. 6 is a code list for despreading a CCK modulated signal in the 802.11b system. It is a figure which shows the structure of the de-spreader in the CDMA demodulation which is a related technique. It is a figure which shows the structure of the FWT calculator in the CCK demodulation which is a related technique. It is a figure which shows the structure of the de-spreading apparatus of the spread spectrum communication of 3rd Embodiment.

(First embodiment)
First, an outline of a method for demodulating a CCK signal in the present embodiment will be described.

When the equation (2) of the CCK signal obtained previously is examined, the CCK-modulated signal C is

As a spread symbol,

・・・式（３）
を、拡散符号（以下ＣＣＫ符号）とみなした、ＤＳＳＳ変調の一種であることがわかる。

... Formula (3)
Is a kind of DSSS modulation, which is regarded as a spreading code (hereinafter referred to as CCK code).

That is, on the receiving side, the received signal C is despread with an appropriate CCK code, thereby spreading symbols

Can be demodulated.

  Therefore, on the receiving side, for demodulation, first, the received signal is despread using all the CCK codes in FIG. 6 to obtain a correlation value. FIG. 6 is a list of CCK codes corresponding to the combinations of d2,..., D7. In FIG. 6, c0, c1,..., C7 represent chips of each CCK code (c0, c1,..., C7 from the top).

  After that, among the correlation values, the one having the maximum correlation value is determined as a transmitted signal, and is selected as a despread signal. Further, from the selected maximum correlation value, signals before modulation (d2,..., D7 in FIG. 6) corresponding to the CCK code that generated the correlation value are generated.

  The configuration of the spread spectrum communication system of the first embodiment will be described below using the drawings.

  FIG. 1 is a diagram illustrating a configuration of a receiving device 10 according to the first embodiment. The receiving apparatus 10 includes a radio receiving antenna 11 that receives a transmitted radio signal and inputs the received signal to the radio receiving unit, and a radio receiving unit 12 that converts the received signal into a baseband signal and outputs the baseband signal. The receiving apparatus 10 further includes a despreading unit 13 that despreads a received signal using a spreading code corresponding to CCK or DSSS, and a demodulating unit 14 that demodulates phase shift modulation.

  FIG. 2 shows a configuration example of the despreading unit 13 in FIG. The despreading unit 13 generates one of a plurality of spreading codes and outputs the generated spreading code to the correlation unit 21, and performs a correlation operation between the received signal and the given spreading code. The correlation unit 21 outputs the correlation value 27. Further, the despreading unit 13 searches for a correlation value having the maximum value from the correlation values 27, and outputs a maximum correlation value 28 and a peak value signal 29 indicating the maximum value number. The phase control unit 23 adjusts the timing of the multiple code generation unit 20 using the peak position signal 29. Further, the despreading unit 13 outputs the first switching unit 25 that switches whether the correlation value 27 is output to the demodulation unit 14 or not, and whether the maximum correlation value 28 and the peak position signal 29 are output to the demodulation unit 14 or not. A second switch unit 26 for switching between the two. Further, the despreading unit 13 includes an output selection unit 24 that performs switching control between the first switch unit 25 and the second switch unit 26.

  FIG. 3 shows a configuration example of the multiple code generator 20 in FIG. The multiple code generator 20 includes multiple spread code generators 30-1 to 30-3 and a code selection unit 31. The code selection unit 31 selects which output of the spread code generators 30-1 to 30-3 is output to the correlation unit 21. Also, it has a function of delaying the phase of the spread code from the spread code generators 30-1 to 30-3 based on the control signal from the phase control unit 23.

For example, in FIG. 3, the first spreading code generator 30-1 is an 802.11b Barker code generator, and the second spreading code generator 30-2 is an 802.11b CCK code generator. Further, the third spreading code generator 30-3 is a W-CDMA type spreading code generator.
(Description of operation)
Next, the operation of the first embodiment will be described with reference to the block diagram showing the configuration example of the despreading section in FIG. 2 and the block diagram showing the configuration example of the multiple code generator in FIG.

  First, details of despreading a W-CDMA signal in the despreading unit 13 shown in FIG. 2 will be described.

  In FIG. 2, the received signal input to the despreading unit 13 is input to the correlation units 21-1 to 21-N. The phase control unit 23 performs timing control so as to despread by shifting the phase of the spread code generated from the multiple code generation units 20-1 to 20-N one symbol at a time.

  The code selection unit 31 switches so as to select the output from the third spreading code generator 30-3 which is a W-CDMA spread code generator. The multiple code generation units 20-1 to 20-N output spreading codes used for synchronization at the timing given from the phase control unit 23 to the correlation units 21-1 to 21-N.

  Correlator 21-1 to N despread the received signal with a synchronization spreading code and outputs correlation values 27-1 to 27 -N. The correlation values 27-1 to 27 -N that are despread by shifting the phases are input to the maximum value search unit 22, and the maximum value search unit 22 outputs the maximum correlation value 28 and the peak position signal 29.

  During this synchronization operation, the output selection unit 24 does not output the correlation values 27-1 to N, the maximum correlation value 28, and the peak position signal 29 to the demodulator 14 at the subsequent stage, and the second switch unit 25 and the second switch unit 25. The switch unit 26 is controlled.

  The peak position signal 29 obtained in this way is input to the phase control unit 23 as the correct timing of despreading, and the subsequent despreading is performed at this timing. In this way, the synchronization operation is completed.

  When synchronization is completed, the phase control unit 23 controls to delay the phase of the spread code generated from the plurality of code generation units 20-1 to 20-N and synchronize with the received signal according to the timing obtained above. The multiple code generator 20-1 outputs to the correlator 21 the spreading code determined as the first of the N spreading codes used for code multiplexing by the W-CDMA system. The correlator 21-1 generates a correlation value 27-1 between the received signal and the first spreading code.

  Similarly, the multiple code generation unit 20-2 outputs the second spreading code of all N to the correlation unit 21-2, and the correlation unit 21-2 generates a correlation value 27-2. Further, the multiple code generation unit 20-N outputs the N-th spread code among all N codes to the correlation unit 21-N, and the correlation unit 21-N generates a correlation value 27-N.

  The output selection unit 24 switches the first switch units 25-1 to 25 -N to output the correlation values 27-1 to 27 -N to the demodulation unit, and outputs the output of the maximum value search unit 22 to the demodulation unit 14. The second switch sections 26-1 to 26-2 are switched so as not to occur. In this way, the despreading process of the W-CDMA signal is performed.

  Next, details of the case where the 802.11b CCK signal is despread in the despreading unit 13 of FIGS. 1 and 2 which is the same as that obtained by despreading the W-CDMA signal will be described.

  The received signal input to the despreading unit 13 is input to the correlation units 21-1 to 21-N. The phase control unit 23 performs timing control so that the multiple code generation units 20-1 to 20-N perform despreading by shifting the phase by one symbol at a time.

  The code selection unit 31 switches to select an output from the first spreading code generator 30-1 that generates a Barker code in order to synchronize with the received signal. The multiple code generators 20-1 to 20-N output Barker codes used for synchronization at the timing given from the phase controller 23 to the correlators 21-1 to 21-N.

  Correlator 21-1 to 21 -N despreads the received signal with a Barker code and outputs correlation value 27. The correlation values 27 despread by shifting the phases are input to the maximum value search unit 22, and the maximum value search unit 22 outputs the maximum correlation value 28 and the peak position signal 29.

  During the synchronization operation, the output selection unit 24 controls the first switch unit 25 and the second switch unit 26 so as not to output the correlation value 27, the maximum correlation value 28, and the peak position signal 29 to the demodulator at the subsequent stage. .

  The peak position signal 29 obtained in this way is input to the phase control unit 23 as the correct timing of despreading, and the subsequent despreading is performed at this timing. In this way, the synchronization operation is completed.

  When the synchronization is completed, the despreading unit 13 despreads the received signal with 64 CCK codes using 64 (N ≧ 64) correlation units 21 out of the N correlation units. The code selection unit 31 switches so as to select the output from the second spreading code generator 30-2 that performs CCK code generation.

  The multiple code generation unit 20-1 outputs the CCK code determined as the first of all 64 to the correlation unit 21-1, and the correlation unit 21-1 generates a correlation value 27-1. For example, in this embodiment, the first code (c0, c1,..., C7 = 0) in the list of CCK codes in FIG. 6 can be used as the first CCK code. The code generation unit 20-2 outputs the second CCK code to the correlation unit 21-2, and the correlation unit 21-2 generates a correlation value 27-2. Similarly, the code generation unit 22-64 outputs the 64th CCK code to the correlation unit 21-64, and the correlation unit 21-64 generates a correlation value 24-64. The maximum value search unit 22 selects the maximum correlation value from the correlation values 27-1 to 27-64 and outputs the maximum correlation value 28. In addition, a peak signal value 29 is output.

The output selection unit 24 switches the first switch units 25-1 to 25-N so as not to output the correlation values 27-1 to 27-N to the demodulation unit, and outputs the output of the maximum value search unit 22 to the demodulation unit. The second switch units 26-1 to 26-2 are switched. In this way, the CCK signal is demodulated.
(Explanation of effect)
As described above, in the present embodiment, the multiple code generation unit 20 and the correlation unit 21 perform the correlation calculation process using the synchronization code at the time of synchronization and the diffusion at the time of despreading, with respect to radio systems using different codes. The despreading process using the code can be switched.

  In addition, the maximum value search unit has a configuration in which the correlation value peak position detection process of the synchronization code can be switched at the time of synchronization, and the selection process of the code having the highest correlation can be switched from the correlation values of a plurality of spreading codes at the time of CCK reception ing. Therefore, despreading can be performed with the same configuration for different wireless systems such as W-CDMA and 802.11b, so that the despreading processing of CDMA and CCK can be realized with the same circuit.

In other words, by adopting the configuration as described above, in the present embodiment, in a communication apparatus using different radio systems, a spectrum in which demodulation processing of different radio systems is realized by the same circuit and circuit sharing is possible. A spread communication receiver can be provided.
(Second Embodiment)
Next, a second embodiment for carrying out the present invention will be described.

  FIG. 4 shows a configuration example of the receiving device 60 that performs rake reception. Rake reception is a technique for improving reception characteristics by despreading and combining each of reception signals (multipath waves) of a plurality of routes by multipath or the like.

  The receiving device 60 includes a radio receiving antenna 11 that inputs a received signal to the radio receiving unit, and the radio receiving unit 12 that converts the received signal into a baseband signal and outputs the baseband signal. Further, the receiving device 60 despreads each signal component of each path from the received signal by using a spreading code corresponding to CCK or DSSS, and combines the phase and time so as to synthesize, and a phase shift modulation. A demodulator 14 for demodulating is provided.

  FIG. 5 shows a configuration example of the rake receiving unit 63 in FIG. The rake receiving unit 63 includes despreading units 71-1 to 71-2 that despread received signals in the respective paths in accordance with the delay information 81-1 to 81-N. Further, the rake receiving unit 63 combines the despread signals of the paths output from the despreading units 71-1 to 71-2 with the phases being aligned according to the delay information 81-1 to 81-N, and outputs the synthesizer A72-1 to 72-N and rake combiners B75-1 to 75-2.

  The despreading units 71-1 to 71-2 receive one of the multiple code generators 20-1 to 20-N that generates one of the plurality of spread codes and the spread code given from the multiple code generator. The correlators 21-1 to 21-N are configured to despread signals and generate correlation values 81-1 to 81-N. Further, the despreading units 71-1 to 71-2 multiply the correlation value 81 by the channel estimation unit 73 that generates a weighting coefficient 82 for rake combining by the channel estimation, and the weighted correlation value 83. Have multipliers 74-1 to 74-N.

Further, the despreading units 71-1 to 71-2 search for the correlation value having the maximum value among the weighted correlation values 83-1 to 83-N, the maximum correlation value 84, and the maximum value number. The maximum value search unit 22 that outputs a peak position signal 85 indicating Further, the despreading units 71-1 to 71-2 use the peak position signal 85 to adjust the timing of the plurality of code generation units 20-1 to 20-N, and the correlation values 83-1 to 83-N. The first switch units 25-1 to 25-N that switch whether the connection destinations are output to the demodulation unit or not. Further, the despreading units 71-1 to 71-2 are second switch units 26-1 to 26-2 and a first switch for switching whether to output the maximum correlation value 28 and the peak position signal 29 to the demodulation unit 14 or not. Output selector 24 that performs switching control of the units 25-1 to 25-N and the second switch units 26-1 to 26-2.
(Description of operation)
Next, the operation of the second embodiment will be described with reference to FIG.

  First, details of the case where the rake receiving unit 63 despreads the W-CDMA signal will be described.

  The received signal input to the rake receiving unit 63 is input to the despreading units 71-1 to 71-2. The despreading unit 71-1 performs despreading in the first path, and the despreading unit 71-2 performs despreading in the second path. The reception signals input to the despreading units 71-1 to 71-2 are input to the correlation unit 21.

  The phase control unit 23 performs timing control so as to despread by shifting the phase of the spread code generated from the multiple code generation units 20-1 to 20-N one symbol at a time. The code selection unit 31 switches so as to select the output from the third spreading code generator 30-3 that generates a W-CDMA spreading code. The multiple code generation units 20-1 to 20-N output spreading codes used for synchronization at the timing given from the phase control unit 23 to the correlation units 21-1 to 21-N.

  Correlator 21-1 to 21 -N despreads the received signal with a spreading code for synchronization, and outputs correlation values 27-1 to 27 -N. During this synchronization operation, the channel estimation unit 73 does not perform channel estimation and weighting coefficient 82 generation. Therefore, the value of the weighting coefficient 82 which is an input to the multipliers 74-1 to 74-N is 1.

  During this synchronization operation, the output selection unit 24 does not output the correlation values 83-1 to 83 -N, the maximum correlation value 85, and the peak position signal 86, and the first switch units 25-1 to 25 -N and The second switch units 26-1 to 26-2 are controlled.

  Correlation values 81-1 to 81-N that are despread by shifting the phases are input to the maximum value search unit 22, and the maximum value search unit 22 outputs a maximum correlation value 85 and a peak position signal 86. The peak position signal 86 obtained in this way is input to the phase controller 23 as the correct timing of despreading, and the subsequent despreading is performed at this timing. In this way, the synchronization operation is completed.

  When the synchronization is completed, the phase control unit 23 controls the phases of the multiple code generation units 20-1 to 20-N according to the synchronized timing. The multiple code generator 20-1 outputs the first spread code among the spread codes to the correlation unit 21. The correlator 21-1 generates a correlation value 81-1 between the received signal and the first spreading code. Similarly, the multiple code generator 20-2 outputs the second spreading code to the correlator 21-2, and the correlator 21-2 generates the second correlation value 81-2. Similarly, the multiple code generation unit 20-N outputs the Nth spread code to the correlation unit 21-N, and the correlation unit 21-N generates the Nth correlation value 27-N.

  The output selecting unit 24 outputs the first switch units 25-1 to 25-N to the rake combining units A72-1 to 72-N, and performs a rake combining process of the first path and the second path. On the other hand, the second switch units 26-1 to 26-2 are switched so as not to be output to the rake combining units B75-1 to 75-2. In this way, the W-CDMA signal is subjected to despreading processing and rake reception processing.

Next, details of despreading an 802.11b signal according to the second embodiment will be described.
The received signal input to the rake receiving unit 63 is input to the despreading units 71-1 to 71-2. The despreading unit 71-1 performs despreading in the first path, and the despreading unit 71-2 performs despreading in the second path.

  The received signals input to the despreading units 71-1 to 71-2 are input to the correlation units 21-1 to 21-N. The phase control unit 23 performs timing control so as to despread by shifting the phase of the spread code generated from the multiple code generation units 20-1 to 20-N one symbol at a time. The code selection unit 31 switches to select an output from the first spreading code generator 30-1 that generates a Barker code in order to synchronize with the received signal.

  The multiple code generation unit 20 outputs spreading codes used for synchronization at timing given from the phase control unit 23 to the correlation units 21-1 to 21-N. Correlator 21-1 to 21-N despreads the received signal with a Barker code and outputs correlation values 81-1 to 81-N.

  During this synchronization operation, the channel estimation unit 73 does not perform channel estimation and weighting coefficient 82 generation. Therefore, the value of the weighting coefficient 82 which is an input to the multipliers 74-1 to 74-N is 1. During this synchronization operation, the output selection unit 24 controls the first switch unit 25 and the second switch unit 26 so as not to output the correlation value 27, the maximum correlation value 85, and the peak position signal 86.

  Correlation values 81-1 to 81-N that are despread by shifting the phases are input to the maximum value search unit 22, and the maximum value search unit 22 outputs a maximum correlation value 85 and a peak position signal 86. The peak position signal 86 obtained in this way is input to the phase controller 23 as the correct timing of despreading, and the subsequent despreading is performed at this timing. In this way, the synchronization operation is completed.

  When the synchronization is completed, the despreading unit 71 despreads the received signal with 64 CCK codes using 64 (N ≧ 64) correlation units 21 out of the N correlation units. The code selection unit 31 switches so as to select the output from the second spreading code generator 30-2 that performs CCK code generation.

  The multiple code generation unit 20-1 outputs the first CCK code to the correlation unit 21-1, and the correlation unit 21-1 generates a correlation value 81-1. Similarly, the code generation unit 20-2 outputs the second CCK code to the correlation unit 21-2, and the correlation unit 21-2 generates a correlation value 81-2.

  Similarly, the code generator 22-64 outputs the 64th CCK code to the correlator 21-64, and the correlator 21-64 generates a correlation value 81-64. The maximum value search unit 22 selects the maximum correlation value from the correlation values 81-1 to 81-64, outputs the maximum correlation value 85, and outputs the peak signal value 86.

The output selection unit 24 switches the first switch units 25-1 to 25 -N so as not to output the correlation values 27-1 to 27 -N to the rake combining units A 72-1 to 72 -N, while the maximum value search unit 22. The second switch units 26-1 to 26-2 are switched so as to output the output to the rake combining units B 75-1 to 75-2. In this way, rake synthesis demodulation processing of the CCK signal is performed.
(Explanation of effect)
As described above, in this embodiment, similarly to the first embodiment, W-CDMA and 802.11b despreading are possible with the same configuration, and a receiving apparatus corresponding to both is configured. In addition, the circuit can be shared.

  In addition to the above effects, in a multipath environment where signals that have passed through multiple paths are received due to radio wave reflection etc., the signal components of each path are extracted separately from the received signal, and the phase and time are aligned. It is also possible to adopt a configuration of rake reception to be combined.

In other words, in the present embodiment, it becomes possible to share a despreading device in a receiving device for demodulating different radio systems, and improve error rate characteristics during demodulation while suppressing an increase in hardware scale. A spread spectrum communication receiver can be provided.
(Third embodiment)
Next, a third embodiment for carrying out the present invention will be described.

  FIG. 9 shows the configuration of a despreading apparatus for spread spectrum communication according to the third embodiment.

  A spread spectrum communication despreading apparatus 900 according to the third embodiment includes a code generation unit 901 capable of outputting any one of two or more different code schemes, a spread code output from the code generation unit, and reception. Correlation means 902 for generating a correlation value with the signal. Further, the despreading apparatus 900 for spread spectrum communication includes a despreading unit 910 that includes the code generation unit 901 and the correlation unit 902 and outputs the correlation value.

  As described above, the present embodiment has the following effects.

  That is, by adopting the configuration as described above, in the present embodiment, in a communication apparatus using different radio systems, demodulation processing of different radio systems is realized with the same circuit, and spread spectrum that enables circuit sharing A communication despreading device can be provided.

DESCRIPTION OF SYMBOLS 10 Receiver 11 Reception antenna 12 Radio | wireless receiver 13 Despreading part 14 Demodulation part 20 Multiple code generator 21 Correlation part 22 Maximum value search part 23 Phase control part 24 Output selection part 25 1st switch part 26 2nd switch part 27 Correlation value 30 Spreading code generator 31 Code selection unit 60 Receiving device 63 Rake receiving unit 71 Despreading unit 72 Rake combining unit A
73 Channel Estimation Unit 74 Multiplier 75 Rake Synthesis Unit B
110 Despreading Unit 111 Code Generation Unit 112 Correlation Unit 113 Correlation Value 120 FWT Operation Unit 121 Serial / Parallel (S / P) Conversion Unit 122 BFWB
123 Maximum value search part

Claims (10)

Code generating means capable of outputting any one of two or more different spreading codes;
Correlation means for generating a correlation value between the spread code output from the code generation means and the received signal;
And a despreading unit for outputting the correlation value.   2. The spread spectrum communication despreading apparatus according to claim 1, wherein the code system includes a CCK code and a Barker code.   3. The spread spectrum communication despreading apparatus according to claim 2, wherein the code system further includes a code other than a CCK code and a Barker code. The despreading device according to any one of claims 1 to 3, provided for each of a plurality of transmission paths;
Channel estimation means for performing channel estimation for each of the transmission paths and outputting a weight coefficient for rake combining;
Multiplication means for multiplying each of the correlation values by the weighting coefficient for the transmission path corresponding to the correlation value and outputting as a weight correlation value;
A rake receiving device for spread spectrum communication, comprising: rake combining means for adding the weight correlation values for each of the transmission paths. Including the despreading device according to any one of claims 1 to 3;
Wireless receiving means for inputting a received signal to the despreading device;
Demodulation means to which an output signal from the despreading device is input;
A spread spectrum communication receiver. A rake receiving device according to claim 4,
Wireless receiving means for inputting a received signal to the rake receiving device;
Demodulation means to which an output signal from the rake receiver is input;
A spread spectrum communication receiver. Output one of two or more different spreading codes,
Generating a correlation value between the output spread code and the received signal;
Outputting the correlation value;
A despreading method for spread spectrum communication.   8. The spread spectrum communication despreading method according to claim 7, wherein the coding method includes a CCK code and a Barker code.   9. The spread spectrum communication despreading method according to claim 8, wherein the code system further includes a code other than a CCK code and a Barker code. For each of the plurality of transmission paths, a despreading method according to any one of claims 7 to 9 is despread to output a correlation value,
Perform channel estimation for each of the transmission paths and output a rake combining weighting factor;
Each of the correlation values is multiplied by the weighting factor for the transmission path corresponding to the correlation value and output as a weight correlation value,
Rake reception method for spread spectrum communication reception, characterized in that the weight correlation value for each of the transmission paths is added to perform rake synthesis.

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