JP5085458B2 - Communication device - Google Patents

Description

  The present invention uses, for example, a Viterbi decoding method as an error correction method in a digital wireless communication system that transmits and receives a plurality of signals such as MIMO (Multi Input Single Output) and MISO (Multi Input Single Output). The present invention relates to a wireless communication system that transmits and receives via each antenna switching unit on the reception side, and in particular, a propagation path state determination unit that determines the state of each propagation path on the reception side in order to improve the error correction characteristics by Viterbi decoding. The present invention relates to a communication apparatus that controls the form of transmission based on the fed back propagation path characteristic information by feeding back the propagation path characteristic information from the propagation path state determination unit to the transmission side.

  2. Description of the Related Art Conventionally, a communication apparatus configured as shown in FIGS. 2A and 2B is known as this type of communication apparatus.

  That is, (a) and (b) of FIG. 2 are block diagrams showing a configuration of encoding (transmission side) / decoding (reception side) in the prior art of the communication apparatus as described above.

  In this case, the transmission side shows an example in which two signals are separately transmitted from the radio units 206 and 207 via the transmission antennas 208 and 209 as two transmitters, respectively.

  FIG. 3 shows an example of the configuration of a convolutional encoder used in the encoding unit 201 shown in FIG.

  As shown in FIG. 2 (a), the transmission side includes an encoding unit 201, a puncture unit 202, a modulation unit 203, an antenna switching unit 204, a control unit 205, radio units 206 and 207, and transmission antennas 208 and 209. Has been.

  Also, as shown in FIG. 2B, the receiving side includes a receiving antenna 210, a radio unit 211, a separation unit 212, a switching unit 213, a control unit 214, a depuncture unit 215, and a Viterbi decoding unit 216. .

  On the transmission side, transmission bits (b0, b1, b2,...) Are input to the encoding unit 201, and encoded data (2 bits) is output.

  Here, the encoding unit 201 performs convolutional encoding. As an example of the configuration, the encoding unit 201 performs convolutional encoding on transmission bits (b0, b1, b2,...) As shown in FIG. As a result, G0, G1, G2,... And P0, P1, P2.

  The output from the encoding unit 201 is input to the puncturing unit 202, and the bits are partially thinned out to obtain a desired encoding rate, and then input to the modulation unit 203.

  Modulating section 203 performs symbol modulation on the output from puncturing section 202.

  Here, in FIG. 2A, an encoding rate of 3/4 is shown as an example.

  The antenna switching unit 204 distributes the output from the modulation unit 203 to the radio unit 206 and the radio unit 207 by switching paths according to the control of the control unit 205.

  At this time, the control unit 205 does not perform switching control based on a special condition, but controls the switching unit 204 to simply switch alternately, for example.

  The data distributed by the switching unit 204 is transmitted from the transmission antenna 208 and the transmission antenna 209 to the reception side via the wireless unit 206 and the wireless unit 207.

  On the receiving side, as shown in FIG. 2B, the signal received via the receiving antenna 210 is converted into a baseband signal by the wireless unit 211, and the two transmissions included in the received signal are separated by the separating unit 212. Separate the signal.

  Here, as a method of separation by the separation unit 212, for example, MLD (Maximum Likelihood Detection) may be mentioned.

  Then, the two signals separated by the separation unit 212 are combined into one signal by the switching unit 213 and input to the depuncture unit 215.

  The antenna switching unit 213 is controlled by the control unit 214 and operates in the same manner as the control unit 205 on the transmission side.

  The depuncture unit 215 handles the portion thinned out on the transmission side as indeterminate data, and inputs the result to the Viterbi decoding unit 216.

  The Viterbi decoding unit 216 performs error correction based on the output of the depuncture unit 215 under the condition that the uncertain data portion is not considered in the decoding process, and the corrected bits (b ^ 0, b ^ 1, b ^ 2, ...) are output.

In addition to the disclosure of the conventional communication apparatus shown in FIGS. 2 (a) and 2 (b), Japanese Patent Laid-Open No. 2004-26883 discloses “In order to improve the error correction characteristics by Viterbi decoding, By providing a propagation path state determination unit for determining the state of the path and feeding back the propagation path characteristic information from the propagation path state determination unit to the transmission side, the transmission mode can be changed based on the fed back propagation path characteristic information. A communication device configured to control is disclosed.
JP 2004-40232 A

  In general, when puncture (depuncture) is adopted, the characteristics are deteriorated as compared with the case where it is not adopted, and this indicates that the decoding capability is reduced by thinning out data. .

  That is, a pair that has not been thinned ((1) in FIGS. 2A and 2B) and a pair that has been thinned (2 in FIGS. 2A and 2B) Then, the degree of causing a decoding error is different.

  When puncturing (depuncturing) is employed, decoding is performed without considering the thinned data portion, so the remaining 1 bit (G2, P3 in FIGS. 2A and 2B) is incorrect. The influence of the case is great.

  Therefore, it is desired that the thinned data portion is distributed so as to be transmitted through a path less prone to error by control of the antenna switching unit.

  However, in the conventional communication apparatus as shown in FIGS. 2A and 2B, the data portion thinned out as described above is not considered to be transmitted through a path that is less prone to error. The antenna switching unit distributes data according to a certain rule (for example, simply switching alternately).

  Further, in Patent Document 1, “in order to improve the characteristics of error correction by Viterbi decoding, a propagation path state determination unit for determining the state of each propagation path is provided on the receiving side, and propagation from the propagation path state determination unit is performed. By feeding back the path characteristic information to the transmitting side to control the form of transmission based on the fed back propagation path characteristic information, the data part whose error resistance has been reduced by controlling the antenna switching unit Is not considered at all, and when the control unit controls the antenna switching unit according to the determination result of the propagation path state on the receiving side, the antenna switching is performed on the encoded data. No consideration is given to performing according to the puncture pattern.

  Therefore, the present invention has been made in view of the above points, and uses a Viterbi decoding method as an error correction method of a digital wireless communication system that transmits and receives a plurality of signals. In a wireless communication system that transmits and receives via an antenna switching unit, the state of a propagation path is monitored on the receiving side, a path that is less likely to be erroneous is determined, and when the antenna switching unit is controlled according to the result, encoded data By controlling the switching unit that is performed according to the puncture pattern, it is possible to provide a communication device that distributes data so that the thinned data portion is transmitted through a path that is less prone to error by controlling the antenna switching unit. It is aimed.

According to the present invention, in order to solve the above problems,
Viterbi decoding method is used as an error correction method, and a plurality of signals thinned out by the puncture process and the depuncture process of the encoded data by the puncture unit on the transmission side and the depuncture unit on the reception side, and the control units on the transmission side and the reception side In a radio communication system that transmits and receives via each antenna switching unit on the transmission side and reception side controlled by
On the receiving side, a propagation path state determination unit that determines a state of a propagation path that propagates the plurality of signals and outputs propagation path characteristic information is provided,
By feeding back the propagation path characteristic information output from the propagation path state determination unit provided on the reception side to the transmission side control unit, and notifying the reception side control unit, the transmission side control unit and Control each antenna switching unit on the transmission side and reception side by the control unit on the reception side,
In order to transmit the data part whose tolerance against data error is reduced by thinning out by the puncture process and the depuncture process of the encoded data through a path less prone to error, according to the determination result of the propagation path state on the reception side When the control unit on the transmission side and the control unit on the reception side control the antenna switching units on the transmission side and the reception side, antenna switching is performed according to the puncture pattern of the encoded data. A communication device is provided.

  In the present invention, a Viterbi decoding method is used as an error correction method in a digital wireless communication system that transmits and receives a plurality of signals, and reception is performed in a wireless communication system that transmits and receives a plurality of signals via respective antenna switching units on the transmission side and the reception side. By monitoring the state of the propagation path on the side, determining a path that is less prone to error, and controlling the switching unit according to the result, the thinned data part is more error controlled by the control of each antenna switching unit Data can be distributed so that it is transmitted through a difficult path, and a part that has been less resistant to data errors due to puncturing (depuncture) processing can be transmitted along a path that is less prone to error. Thereby, the characteristic of the Viterbi decoding result can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIGS. 1A and 1B are block diagrams showing a configuration of encoding (transmission side) / decoding (reception side) of a communication apparatus according to an embodiment of the present invention.

  That is, the communication apparatus according to the present invention basically uses a Viterbi decoding method as an error correction method as shown in FIGS. 1A and 1B, and uses a transmission side puncture unit 202 and a reception side puncture. A plurality of signals thinned out by the puncture process and the depuncture process of the encoded data by the unit 215, and the antenna switching units 204 on the transmission side and the reception side controlled by the control units 205 and 214 on the transmission side and the reception side, In the wireless communication system that transmits and receives via 213, a propagation path state determination unit 101 that determines a state of a propagation path that propagates the plurality of signals and outputs propagation path characteristic information is provided on the reception side. The propagation path state information output from the propagation path state determination unit 101 provided to the feedback side is fed back to the control unit 205 on the transmission side and the control unit 2 on the reception side 4, the transmitting-side control unit 205 and the receiving-side control unit 214 control the transmitting-side and receiving-side antenna switching units 204 and 213, and the encoded data puncturing process and In order to transmit the data portion whose tolerance to data errors is reduced by depuncturing processing through a path that is less prone to error, the control unit 205 on the transmission side according to the determination result of the propagation path state on the reception side. When the control unit 214 on the reception side controls the antenna switching units 204 and 213 on the transmission side and the reception side, antenna switching is performed according to the puncture pattern of the encoded data.

  Here, as shown in FIG. 1A, on the transmission side, two signals are separately transmitted from the radio units 206 and 207 via the transmission antennas 208 and 209 as two radio units.

  As shown in FIG. 1 (a), the transmission side includes an encoding unit 201, a puncturing unit 202, a modulation unit 203, a switching unit 204, a control unit 205, radio units 206 and 207, and transmission antennas 208 and 209. ing.

  Also, as shown in FIG. 1B, the reception side includes a reception antenna 210, a radio unit 211, a separation unit 212, a switching unit 213, a propagation path state determination unit 101, a control unit 214, a depuncture unit 215, and Viterbi decoding. The unit 216 is configured.

  On the transmission side, transmission bits (b0, b1, b2,...) Are input to the encoding unit 201, and encoded data (2 bits) is output.

  Here, the encoding unit 201 performs convolutional encoding. As an example of the configuration, the encoding unit 201 performs convolutional encoding on transmission bits (b0, b1, b2,...) As shown in FIG. , G0, G1, G2,... And P0, P1, P2... Are output as encoded 2-bit data.

  The encoded 2-bit data G0, G1, G2,... And P0, P1, P2... Output from the encoding unit 201 are input to the puncturing unit 202 and are partly set to have a desired encoding rate. After bits are thinned out, they are input to the modulation unit 203.

  Modulating section 203 performs symbol modulation on the output from puncturing section 202.

  Here, in FIG. 1A, a coding rate of 3/4 is shown as an example.

  The antenna switching unit 204 distributes the output from the modulation unit 203 to the radio unit 206 and the radio unit 207 by switching paths according to the control of the control unit 205.

  At this time, as will be described later, the control unit 205 controls the antenna switching unit 204 on the transmission side based on the channel characteristic information fed back from the channel state determination unit 101 provided on the reception side. Yes.

  That is, the control unit 205 performs propagation on the receiving side in order to transmit a data portion that has been less resistant to data errors by being thinned out by the puncture processing and depuncture processing of the encoded data through a path that is less prone to error. When controlling the antenna switching unit 204 on the transmission side according to the determination result of the road state, the antenna switching is performed according to the puncture pattern of the encoded data.

  Data distributed by the antenna switching unit 204 is transmitted from the transmission antenna 208 and the transmission antenna 209 to the reception side via the wireless unit 206 and the wireless unit 207.

  The processing on the transmission side is basically the same as that of the conventional communication apparatus described based on FIG. 2A except for antenna switching by the control unit 205.

  That is, the control unit 205 controls switching of the antenna switching unit 204 according to the determination result of the propagation path state fed back from the propagation path state determination unit 101 provided on the reception side.

  On the transmission side, when transmitting a signal, it is assumed that means for transmitting a known signal such as a preamble signal or a pilot signal in addition to transmission data is provided in the wireless unit 206 and the wireless unit 207, for example. .

  These known signals are signals necessary for determining a propagation path state to be described later.

  On the reception side, the received signal is converted into a baseband signal by the radio unit 211 and input to the propagation path state determination unit 101.

  The propagation path state determination unit 101 calculates propagation path characteristics from a known signal included in the received signal from the radio unit 211, determines a path that is less likely to be erroneous, and feeds back the determination result to the control unit 205 on the transmission side. At the same time, it notifies the control unit 214 on the receiving side.

  In this case, as a determination criterion of the propagation path state in the propagation path state determination unit 101, for example, the smaller attenuation amount in the propagation path can be determined as a path that is less likely to be erroneous.

  FIG. 1A shows an example in which the amount of attenuation is smaller in the path transmitted from the transmission antenna 208, and the propagation path state determination unit 101 determines that this path is a path that is less prone to error.

  Then, by feeding back the determination result in the propagation path state determination unit 101 to the transmission-side control unit 205, the transmission-side control unit 205 causes the thinned pairs ((a) and (b) in FIG. 1). The antenna switching unit 204 is switched so as to transmit (2)) from the transmission antenna 208.

  Further, since it is necessary to perform the same switching operation on the reception side as on the transmission side, the determination result of the propagation path state determination unit 101 is also notified to the control unit 214.

  Other processing on the receiving side is the same as that of the conventional communication apparatus described with reference to FIG.

  Therefore, as described above, in the present invention, the Viterbi decoding method is used as an error correction method in a digital wireless communication system that transmits and receives a plurality of signals, and a plurality of signals are transmitted and received via each antenna switching unit on the transmission side and the reception side. In the wireless communication system, the reception side monitors the state of the propagation path, determines a path less prone to error, and controls the switching unit according to the result, so that the thinned data portion is By distributing the data so that it is transmitted through a path that is less prone to error by control, and the part that is less resistant to data errors due to puncturing (depuncture) processing is transmitted through the path that is less prone to error Therefore, it becomes possible to provide a communication device capable of improving the characteristics of the Viterbi decoding result.

FIGS. 1A and 1B are block diagrams showing a configuration of encoding (transmission side) / decoding (reception side) of a communication apparatus according to an embodiment of the present invention. FIGS. 2A and 2B are block diagrams showing the configuration of encoding (transmission side) / decoding (reception side) of a communication apparatus in the prior art. FIG. 3 is a diagram illustrating an example of a specific configuration of a convolutional encoder used in the encoding unit 201 in FIGS. 1 and 2.

Explanation of symbols

101: propagation path state determination unit 201: encoding unit 202: puncture unit 203: modulation unit 204: antenna switching unit 205: control unit 206, 207: radio unit 208, 209: transmission antenna 210: reception antenna 211: radio unit 212 : Separation unit 213: Antenna switching unit 214: Control unit 215: Depuncture unit 216: Viterbi decoding unit

Claims (1)

Viterbi decoding method is used as an error correction method, and a plurality of signals thinned out by the puncture process and the depuncture process of the encoded data by the puncture unit on the transmission side and the depuncture unit on the reception side, and the control units on the transmission side and the reception side In a radio communication system that transmits and receives via each antenna switching unit on the transmission side and reception side controlled by
On the receiving side, a propagation path state determination unit that determines a state of a propagation path that propagates the plurality of signals and outputs propagation path characteristic information is provided,
By feeding back the propagation path characteristic information output from the propagation path state determination unit provided on the reception side to the transmission side control unit, and notifying the reception side control unit, the transmission side control unit and Control each antenna switching unit on the transmission side and reception side by the control unit on the reception side,
In order to transmit the data part whose tolerance against data error is reduced by thinning out by the puncture process and the depuncture process of the encoded data through a path less prone to error, according to the determination result of the propagation path state on the reception side When the control unit on the transmission side and the control unit on the reception side control the antenna switching units on the transmission side and the reception side, antenna switching is performed according to the puncture pattern of the encoded data. Communication device.

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