JP2006060852A - Receiving circuit and receiving method used in mobile communications system of spread spectrum communications system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a plurality of communications in parallel, using a small-scaled circuit in a receiving circuit and receiving method used in a mobile communications system of a spread spectrum communications system. <P>SOLUTION: The receiving circuit is used in the mobile communication system of the spread spectrum communication scheme for despreading a signal that is spread at a transmitting side and received via a radio channel, wherein a receiving processing unit is provided for performing despreading, using a spreading code corresponding to one spreading code, when receiving a signal sent from one transmitting side via one radio channel using the one spreading code, and for performing despreading that uses a spreading code corresponding to a plurality of spreading codes, when receiving a signal sent from the one transmitting side via a plurality of radio channels that use the plurality of spreading codes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a spread spectrum communication system that is mounted on a spread spectrum communication apparatus that is mounted on a vehicle, ship, aircraft, or other mobile object, or that is carried by a person, and that is used to access a radio channel of a CDMA mobile communication system The present invention relates to a receiving circuit and a receiving method used in a mobile communication system.

Conventionally, in the field of mobile communication, various systems have been constructed according to differences in communication forms, communication contents, service targets, and the like, and research and development relating to application of new technologies have been actively conducted.
Among these technologies, a primary modulated wave signal generated by digitally modulating a carrier signal with transmission information is multiplied by a predetermined time-series spreading code to spread the frequency spectrum of the signal and transmit it. The CDMA (Code Division Multiple Access) communication system that restores the primary modulated wave signal by performing correlation detection using a spreading code of the same sequence as the received wave at the receiving side is rich in confidentiality, and the frequency in the wireless transmission path In order to have selectivity fading and other characteristics that are not easily affected by fluctuations, interference, and interference, and to be compatible as a random access communication system, studies are being made to apply it to a mobile communication system as a promising multiple access system. Yes.
JP 55-38776 A JP-A-63-14598

  By the way, since the mobile station of such a mobile communication system is configured for the purpose of providing a voice call service, communication is performed via a facsimile terminal device or a data terminal in parallel with the call. Thus, in order to perform communication in parallel with a call in this way, a mobile station device connected to a terminal adapted to the communication content must be used separately.

  It is an object of the present invention to provide a receiving circuit and a receiving method used in a spread spectrum communication type mobile communication system capable of performing a plurality of communications in parallel using a small circuit.

FIG. 1 is a principle block diagram of the present invention.
The present invention includes an antenna sharing unit 11 that performs antenna transmission / reception sharing, modulation units 12 ₁ and 12 ₂ that individually modulate a single carrier wave signal using transmission information, a steep autocorrelation characteristic, and a code sequence Code generators 13 _{1 to} 13 ₄ that individually generate spread codes having a small cross-correlation between them and the frequency spectrum of each modulated carrier wave signal is spread by the spread codes generated by the code generators 13 ₁ and 13 ₂ , respectively. Then, the spread processing means 14 ₁ and 14 ₂ that transmit via the antenna sharing means 11 and the phase of the code generation means 13 ₃ and 13 ₄ are applied to the components of the spread code included in the received wave obtained via the antenna sharing means 11. despreading processing with synchronization means 15 for synchronizing inversely spread by the spreading code generated frequency spectrum of the received wave by the code generating means 13 _3, 13 _4, respectively A stage 16 _1, 16 _2, despreading means 16 _1, 16 ₂ separately demodulate the despread received waves by a demodulation means 17 _1, 17 ₂ to recover the transmission information contained in these received waves It is provided with.

The reception processing unit corresponds to the code generation unit 13 ₃ , the code generation unit 13 ₄ , the despreading processing unit 16 ₁ , and the despreading processing unit 16 ₂ .
(Function)
In the present invention, when more communication paths are required than communication paths formed via the modulation means 12 ₁ , the spread processing means 14 ₁ , the despreading process means 16 ₁ and the demodulation means 17 ₁ , the spread processing means 14 ₂ spreads the frequency spectrum of the carrier signal modulated by the modulation means 12 ₂ with the transmission information by the spread code generated by the code generation means 13 ₂ and transmits it through the antenna sharing means 11. Further, the despreading processing means 16 ₂ reverses the frequency spectrum of the received wave by the spreading code that the code generating means 13 ₄ outputs in phase synchronization with the spread code component of the received wave under the synchronization control of the synchronizing means 15. Spread. Demodulation means 17 ₂ restores transmission information this way demodulates the despread received wave. This makes it possible to set a communication path according to the amount of communication from a specific communication partner.

That is, the modulation means 12 ₂ , code generation means 13 ₂ , 13 ₄ , spreading processing means 14 ₂ , despreading processing means 16 ₂ and demodulation means 17 ₂ are respectively composed of modulation means 12 ₁ , code generation means 13 ₁ , 13 ₃ , In parallel with the radio channel accessed via the spreading processing means 14 ₁ , the despreading processing means 16 ₁ and the demodulating means 17 ₁ , a communication path via a radio channel different from that channel is formed. Since the circuit can be configured with a circuit that is smaller and has a smaller mounting area than the antenna sharing means 11, the synchronization means 15 and others shared within the mobile station apparatus, a plurality of simultaneous transmissions can be made while satisfying the demands for reducing the size and weight of the mobile station. Communication can be performed.

  As described above, according to the present invention, it is possible to perform signal reception processing on a plurality of communication paths by performing spreading processing using a plurality of spreading codes in accordance with the traffic from a specific communication partner. Further, when a plurality of communication channels are formed in parallel from a specific communication partner, a plurality of despreading is performed using a plurality of spreading codes, and when a single communication channel is formed, a despreading is performed using one spreading code. By spreading, it is possible to perform reception processing according to the situation regardless of whether there is a single communication path or a plurality of communication paths.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a diagram showing an embodiment of the present invention.
In the figure, the input / output on the terminal side of the control unit 21 is connected to a handset and is connected to a facsimile terminal, a computer or other data terminal via a predetermined plug. The audio output of the control unit 21 is connected to one input of a multiplier 24 ₁ via an audio codec (CODEC) 22 _S and a modulator (MOD) 23 ₁ , and its output is a frequency converter 25 ₁ and a power amplifier 26 _1. To one input of the hybrid (H) 27. The output of the hybrid 27 is connected to the transmission input terminal of the antenna duplexer (DUP) 28, and the antenna terminal is connected to the antenna 29. One data output of the control unit 21 is directly connected to a connection point between the output of the audio codec 22 _{S and} the input of the modulator 23 ₁ . The other data output of the control unit 21 is connected to one input of a multiplier 24 ₂ via a modulator (MOD) 23 ₂ , and its output is connected to a hybrid 27 via a frequency converter 25 ₂ and a power amplifier 26 _2. Connected to the other input. The output of the oscillator 30 is connected to the carrier signal input of the modulators 23 ₁ and 23 ₂ , and the output of the oscillator 31 is connected to the local oscillation input of the frequency converters 25 ₁ and 25 ₂ . The transmission control output of the control unit 21 is connected to the control inputs of the power amplifiers 26 ₁ and 26 ₂ . The reception output terminal of the antenna duplexer 28 is connected to one input of the multipliers 34 ₁ and 34 ₂ via the reception unit 32 and the synchronization unit 33. The output of the multiplier 34 ₁ is connected to the detection input of the detection unit 35 _{1 and} the input of the synchronization control unit 36. The output of the detection unit 35 ₁ is connected to the input of one of the data input and the voice codec (CODEC) 22 _R of the control unit 21, the output of which is connected to the audio input of the control unit 21. An output of the multiplier 34 ₂ is connected to a detection input of the detection unit 35 ₂ , and an output thereof is connected to the other data input of the control unit 21. One output of the synchronization control unit 36 is connected to the synchronization input detection unit 35 _1, the other output of the synchronous control unit 36 is connected to the synchronization input detection unit 35 _2. The two channel setting outputs of the control unit 21 are connected to control inputs of the diffusion pattern generation units 37 ₁ and 37 ₂ , respectively. The output of the diffusion pattern generator 37 ₁ is connected to the other input of the multipliers 24 ₁ and 34 ₁ and one feedback input of the synchronization unit 33, and the output of the diffusion pattern generator 37 _{2 is} the output of the multipliers 24 ₂ and 34 ₂ . The other input and the other feedback input of the synchronization unit 33 are connected. The two synchronization control outputs of the synchronization unit 33 are connected to the synchronization inputs of the diffusion pattern generation units 37 ₁ and 37 ₂ , respectively.

  As for the correspondence relationship between the present embodiment and the block diagram shown in FIG. 1, the hybrid 27 and the antenna duplexer 28 correspond to the antenna sharing means 11, the modulator 23 corresponds to the modulation means 12, and the spreading pattern generating unit. 37 corresponds to the code generating means 13, the multiplier 24, the frequency converter 25, the power amplifier 26 and the oscillator 31 correspond to the spreading processing means 14, and the receiving section 32 and the synchronizing section 33 correspond to the synchronizing means 15 and multiply. The detector 34 corresponds to the despreading unit 16, and the detection unit 35 and the synchronization unit 36 correspond to the demodulation unit 17.

FIG. 3 is a diagram illustrating a configuration example of a mobile communication system to which the present embodiment is applied.
In the figure, mobile stations 41 ₁ and 41 ₂ to which the present embodiment is applied are connected to a base station 42 via a CDMA communication system radio link, and the base station is connected to a public communication network. FIG. 4 is a diagram for explaining the operation of this embodiment.
The operation of this embodiment will be described below with reference to FIGS.

The control unit 21 of the mobile station 41 ₁ instructs the spread pattern generation unit 37 ₁ to generate a spread pattern corresponding to the control radio channel based on the configuration of the radio zone stored in advance in the memory. The control radio channel controlled by the base station 42 is accessed via one data output and one data input.
In such an access to the control radio channel, the modulator 23 ₁ modulates the carrier wave signal output from the oscillator 30 with the control information output from the control unit 21 to generate a primary modulated wave signal. The multiplier 24 ₁ multiplies the spread pattern output from the spread pattern generator 37 ₁ by the primary modulated wave signal and spreads the frequency spectrum of the signal. In this way, the frequency converter 25 ₁ multiplies the signal output from the multiplier 24 ₁ by the local signal output from the oscillator 31 to perform frequency conversion processing, and the power amplifier 26 ₁ performs the above processing. The obtained transmission wave is amplified to a predetermined power and transmitted to the base station 42 via the hybrid 27, the antenna duplexer 28 and the antenna 29.

Further, the reception wave of the control radio channel is given to the receiving unit 32 via the antenna 29 and the antenna duplexer 28. The receiving unit 32 receives the received wave under the control of the automatic gain control circuit (AGC) that corrects the level fluctuation of the received wave and the automatic frequency control circuit (AFC) that matches the received band with the occupied bandwidth of the received wave. To extract. The synchronization unit 33 includes a synchronization acquisition circuit based on a predetermined method and a synchronization holding circuit (DLL) based on a delay lock tracking method, and these circuits are diffused into components of the diffusion pattern included in the received wave extracted by the reception unit 32. The diffusion patterns output from the patterns 37 ₁ and 37 ₂ are phase-synchronized and the synchronized state is maintained. The multiplier 34 ₁ performs a despreading process opposite to the multiplier 24 ₁ on the received wave based on the spread pattern output from the spread pattern generator 37 _{1 in} this way.

In the synchronization controller 36, the carrier recovery circuit (CR) performs a predetermined signal processing on the signal obtained by the despreading process to sufficiently suppress the modulated wave component, noise and other unnecessary wave components. Generate a signal. Further, the clock recovery circuit (BTR) recovers a clock synchronized with the control information included in the received wave. Detection unit 35 ₁ detects the signal obtained by despreading processing described above on the basis of the such reference carrier signal and the clock, and restores the control information transmitted from the base station 42 gives the control unit 21 .

The control unit 21 accesses the control radio channel in this way, and performs a predetermined control operation according to the incoming / outgoing area and the like of the own station opposite to the base station 42. For example, the mobile station 41 ₁ transmits In the process up to the start of communication with the mobile station 41 ₂ , the control unit 21 of the mobile station 41 ₁ transmits a call signal indicating the destination mobile station 41 ₂ to the base station 42 according to the operation performed by the operator. (FIG. 4 (1)). The base station 42 performs predetermined call processing in accordance with each piece of information included in the call signal, captures a call radio channel (FIG. 5 (1)) that is vacant when setting a call path, A channel designation signal indicating the identification information P ₁ of the spreading code corresponding to the channel is transmitted to the mobile station 41 ₁ (FIG. 4 (2)).

In the mobile station 41 1, the control unit 21 instructs the spreading pattern generation unit 37 ₁ to generate a spreading code corresponding to such identification information. That is, for the uplink audio signal given from the handset, the control unit 21, audio codec 22 _S , modulator 23 ₁ , multiplier 24 ₁ , frequency converter 25 ₁ , power amplifier 26 ₁ , hybrid 27, antenna duplexer 28 For the downlink audio signal that is formed through the transmission path via the antenna 29 and transmitted from the base station 42 to the mobile station 41 ₁ , the antenna 29, the antenna duplexer 28, the reception unit 32, the synchronization unit 33, and the multiplier 34 _{1 are used.} Since the transmission path through the detection unit 35 ₁ , the voice codec 22 _R and the control unit 21 is formed, a radio channel for communication with the base station 42 is determined (FIG. 4 (3)).

On the other hand, the base station 42 captures a call channel (FIG. 5 (2)) according to a predetermined call processing procedure in response to an outgoing call from the mobile station 41 ₁ , and identifies the spreading pattern identification information corresponding to the channel. An incoming call signal indicating P ₂ and the identification number of the destination mobile station is transmitted (FIG. 4 (3)). In the mobile station 41 ₂ , the control unit 21 accesses the control radio channel in the same manner as the control unit 21 of the mobile station 41 ₁ , receives the above-mentioned incoming call signal, and analyzes the content of the signal itself. When the incoming call to the station is recognized, an incoming call response signal is transmitted to the base station 42 (FIG. 4 (5)), and a spreading code corresponding to the identification information P ₂ included in the incoming call signal is generated. commands the generator 37 _1.

In this way, the mobile station 41 ₂ establishes a call radio channel connecting to the base station 42 (FIG. 4 (6)), and a communication path is established between the mobile station 41 ₁ and the base station 42. It is formed. In the mobile stations 41 ₁ and 41 ₂ , the control unit 21 intermittently controls the output of the power amplifier 26 ₁ at a predetermined timing, thereby performing transmission alternately with the base station 42 on the above-described call radio channel. A telephone call is made by a division duplex (TDD) system.

During a call, the base station 42 recognizes that the mobile station 41 ₁ has moved to a point that is close to the own station according to the received electric field level of the call radio channel, and moves through the channel. A power control command requesting the station 41 ₁ to reduce the transmission power is transmitted. In the mobile station 41 ₁ , when the control unit 21 captures and recognizes such a command via the first data input, it instructs the power amplifier 26 ₁ to reduce the output power. Since the power of the transmission wave fed from the power amplifier 26 ₁ to the antenna 29 side is reduced in this way, the base station 42 is caused by the reception of a large level of reception wave as the mobile station 41 ₁ moves. The sensitivity suppression that occurs is avoided.

In addition, as described above, the control unit 21 of the mobile station that starts a voice call spreads to generate a spreading pattern corresponding to the control radio channel based on the configuration of the radio zone stored in advance in the memory. instructs the pattern generator 37 _2, accesses the control radio channels controlled by the base station 42 via the other data output and the other data input as described above.

When accessing such a control radio channel, the same reference number with “2” added to the same reference number instead of each component assigned with reference number “1” is the same. Since the constituent elements indicated by the reference numbers without the attached numbers are used in combination, the description of the basic operations of the respective units is omitted here.
The control unit 21 accesses the control radio channel in this way, and performs a predetermined control operation according to a call that occurs in the own station during a call opposite to the base station 42. For example, from the public communication network When there is an incoming facsimile call with the destination being the mobile station 41 ₁ , the base station 42 captures an empty call radio channel (FIG. 5 (3)) and responds to that channel. transmitting the incoming call signal and the identification information P ₃ of the diffusion pattern showing the identification number of the incoming call destination mobile station (FIG. 4 (4)). When the control unit 21 of the mobile station 41 ₁ recognizes an incoming call to the own station by analyzing the identification number included in such an incoming call signal, it transmits an incoming call response signal to the base station 42 (FIG. 4 (5)). )), and since the command to generate a spreading code corresponding to the identification information P ₃ included in the incoming call signal to the diffusion pattern generation unit 37 _2, between the mobile station 41 ₁ and the public communication network, A communication path through the base station 42 is formed (FIG. 4 (6)).

In this way, in the state where the communication path for the facsimile incoming call is set in parallel during the voice call, the control unit 21 transfers the signal given from the facsimile terminal to the modulator 23 ₂ , and conversely, the detection unit 35. _The digital signal output from ₂ is given to the facsimile terminal. Further, the control unit 21, also in the second allocated call radio channel to a call in the same manner as in the first call for a radio channel assigned to the call, division duplex when intermittently the output of the power amplifier 26 ₂ The communication (TDD) method is realized, and the output levels of the power amplifiers 26 ₁ and 26 ₂ are variably controlled in conjunction with the power control command received from the base station 42.

  As described above, according to the present embodiment, a mobile station apparatus configured exclusively for voice communication has a modulator that performs primary modulation, a multiplier that performs spreading processing, a spreading pattern generation unit, a frequency converter, a power amplifier, and despreading. Like a multiplier that performs processing and a small-scale circuit such as a detector that restores the primary modulated wave signal, and an oscillator that determines the antenna system, radio channel transmission / reception system, synchronization control system, and transmission frequency By sharing a circuit that has a large circuit scale or requires a large mounting space, a communication path can be formed in parallel for a plurality of calls at the same time.

  That is, while satisfying the requirements for weight reduction and miniaturization originally required for a mobile station device, for example, voice communication and data communication using a facsimile terminal or other data terminal are performed in parallel, Since data communication using the data terminal can be performed in parallel, the probability that an incomplete call will occur because the destination mobile station is busy is reduced. Thus, data transmission to a desired destination can be performed using a facsimile terminal or the like without interrupting the call.

In the present embodiment, the case where a facsimile call is generated during a call is shown. However, the present invention is not limited to such a call. For example, an outgoing call or an incoming call related to a personal computer or other data terminal can be performed. Even if it occurs, it can be similarly applied as long as the control unit 21 can perform the call processing related to the call in parallel.
In this embodiment, the radio channel for call is allocated to the mobile station according to the spreading pattern designated by the base station according to a predetermined communication control procedure. However, the present invention is limited to such a method. For example, when a mobile station accesses a radio channel corresponding to the selected spreading pattern by assigning a plurality of spreading patterns in advance and selecting an available one of these spreading patterns as appropriate. It can be similarly applied to.

Further, in the present embodiment, nothing is defined about the modulation processing method performed by the modulators 23 ₁ and 23 ₂ , but the present invention adds a small-scale circuit as described above, and a large-scale circuit. Any method may be used as long as a parallel call state can be realized for a plurality of calls by sharing a circuit and a circuit that requires a large mounting space. As for the spread spectrum method, if the original requirements for the mobile station apparatus are satisfied in the same manner, for example, a direct spread method, a frequency hopping method, a time hopping method, and a hybrid method based on a combination thereof can be applied. is there.

It is a principle block diagram of the present invention. It is a figure which shows one Example of this invention. It is a figure which shows the structural example of the mobile communication system to which a present Example is applied. It is a figure explaining the operation | movement of a present Example. It is a figure explaining the allocation of a diffusion pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Antenna sharing means 12 Modulation means 13 Code generation means 14 Spreading processing means 15 Synchronization means 16 Despreading processing means 17 Demodulation means 21 Control unit 22 Voice codec (CODEC)
23 Modulator (MOD)
24, 34 Multiplier 25 Frequency converter 26 Power amplifier 27 Hybrid (H)
28 Antenna duplexer (DUP)
DESCRIPTION OF SYMBOLS 29 Antenna 30, 31 Oscillator 32 Reception part 33 Synchronization part 35 Detection part 36 Synchronization control part 37 Spreading pattern generation part 41 Mobile station 42 Base station

Claims (2)

In a receiving circuit used in a mobile communication system of a spread spectrum communication system that performs spreading processing on the transmitting side and performs despreading processing on a signal received via a radio channel,
When a signal is received via one radio channel using one spreading code sent from one transmitting side, despreading is performed with a spreading code corresponding to the one spreading code, and the 1 When receiving a signal via a plurality of wireless channels using a plurality of spreading codes sent from the transmission side of the receiver, a reception processing unit is provided that performs despreading using spreading codes corresponding to the plurality of spreading codes. A receiving circuit characterized by the above. In a reception method used in a mobile communication system of a spread spectrum communication system that performs spread processing on the transmission side and performs despread processing on a signal received via a wireless channel,
When a signal is received via one radio channel using one spreading code sent from one transmitting side, despreading is performed with a spreading code corresponding to the one spreading code, and the 1 When receiving a signal via a plurality of radio channels using a plurality of spreading codes sent from the transmitting side of the receiver, despreading is performed using spreading codes corresponding to the plurality of spreading codes. Method.

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