JP2009273180A - Transmission device and transmission method, and reception device and reception method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission device that improves signal quality of an uplink and a downlink. <P>SOLUTION: The transmission device simultaneously transmits different signals from a plurality of antennas by radio. The device includes: a pilot multiplexing means of multiplexing pilot channels transmitted from the respective antennas by one or more of a time-division multiplexing system; a frequency-division multiplexing system, and a code-division multiplexing means; a data multiplexing means of time-multiplexing pilot channels and data channels; and a means of transmitting signals by at least one of a space-division multiplexing (SDM) system and a time-space transmission diversity (STTD) system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of wireless communication, and more particularly to a transmission device, a transmission method, a reception device, and a reception method for a downlink channel.

  In a third generation communication system represented by IMT-2000 (International Mobile Telecommunications-2000), an information transmission rate of 2 Mbps is realized using a 5 MHz frequency band in the downlink. However, future communication systems are required to further increase the transmission rate, increase the capacity, and reduce the cost. Also, it is necessary to reduce the power consumption of the mobile station. For example, Non-Patent Document 1 describes a technique for improving transmission quality by adopting a multi-input multi-output (MIMO) system.

A. Van Zelst, “Space division multiplexing algorithm”, Proc. 10th Med. Electrotechnical Conference 2000, pp. 1218-1221

  An object of the present invention is to provide a transmission / reception apparatus and a transmission / reception method that improve signal quality in uplink and downlink.

  In the present invention, a transmitting apparatus that simultaneously transmits different signals from each of a plurality of antennas is used. The apparatus includes pilot multiplexing means for multiplexing pilot channels transmitted from each antenna in one or more of time division multiplexing, frequency division multiplexing, and code division multiplexing, Data multiplexing means for time-multiplexing data channels, and means for transmitting signals in at least one of a space division multiplexing (SDM) system and a space-time transmission diversity (STTD) system.

  According to the present invention, signal quality in the uplink and downlink can be improved.

1 shows a block diagram of a MIMO multiplexing system transmitter. FIG. It is a figure which shows a mode that the positional relationship of a serial-parallel conversion part and an interleaver was changed. 1 shows a block diagram of a MIMO multiplexing receiver. FIG. 1 shows a block diagram of a MIMO diversity transmitter. FIG. 1 is a block diagram of a MIMO diversity receiver. FIG. It is explanatory drawing for demonstrating operation | movement of a MIMO diversity system. The conceptual diagram of the system which combined the MIMO multiplexing system and the MIMO diversity system is shown. The conceptual diagram in the case of transmitting a signal from one transmission antenna is shown. It is a figure which shows an example of the multiplexing in the case of transmitting a pilot channel from one transmission antenna. FIG. 5 is a diagram (part 1) illustrating a state of multiplexing while distinguishing pilot channels transmitted from four transmission antennas. It is FIG. (2) which shows a mode that it multiplexes, distinguishing the pilot channel transmitted from four transmission antennas. It is FIG. (3) which shows a mode that it multiplexes, distinguishing the pilot channel transmitted from four transmission antennas.

  According to one aspect of the present invention, when signals are transmitted by the MIMO scheme, pilot channels transmitted from each antenna are multiplexed by one or more of the TDM scheme, FDM scheme, and CDM scheme. The pilot channel and data channel are time multiplexed. The signal is transmitted using one or both of a space division multiplexing (SDM) scheme and a space-time transmission diversity (STTD) scheme.

  By adopting the MIMO system, the information transmission rate can be improved or the diversity effect can be improved, which can contribute to the improvement of signal quality. Since the pilot channel is transmitted while being distinguished for each antenna, the propagation path can be estimated accurately.

  According to one aspect of the present invention, pilot channels transmitted from each antenna are multiplexed by frequency division multiplexing or code division multiplexing, regardless of time division multiplexing. Thereby, even when a period in which the number of users accommodated in one TTI (Transmission Time Interval) is less than the maximum number of users occurs, resource use efficiency can be improved.

  According to one aspect of the present invention, signals are transmitted using an orthogonal frequency code division multiplexing (OFCDM) scheme.

  According to one aspect of the present invention, a signal sequence to be transmitted is distributed to each of the antennas by the serial-parallel conversion unit, and the arrangement of signals in one or more output signal sequences of the serial-parallel conversion unit is changed by the interleaving unit. The The transmission quality can be improved by changing the arrangement of the signals transmitted from the antenna.

  According to one aspect of the present invention, a signal sequence to be transmitted is distributed to each of the antennas by the serial / parallel conversion unit, and the arrangement of signals in the input signal sequence of the serial / parallel conversion unit is changed by the interleaving unit. Thereby, since the arrangement of signals can be changed between a plurality of antennas, a large interleaving effect can be obtained.

  According to an aspect of the present invention, when a signal is received by a MIMO receiver, a time-multiplexed pilot channel and a data channel are separated, and one or more of time multiplexing, frequency multiplexing, and code multiplexing methods are used. The pilot channels for each transmit antenna, multiplexed in a manner, are separated. The control channel is demodulated by both a demodulation method of a signal transmitted by one antenna and a space-time transmission diversity (STTD) method. As a result, the control channel can be quickly demodulated from any type of base station.

[MIMO multiplexing]
FIG. 1 shows a block diagram of a MIMO transmitter that can be used in one embodiment of the present invention. The MIMO multiplexing method is also referred to as a MIMO space division multiplexing (MIMO-SDM (MIMO-Space Division Multiplexing)) method. Such a transmitter is typically provided in a base station, but may be provided in a mobile station. The transmitter used in this embodiment is an Orthogonal Frequency Code Division Multiple Access (OFCDM) transmitter, but other embodiments may employ other schemes. . The transmitter includes a turbo encoder 102, a data modulation unit 104, a serial-to-parallel conversion unit 106, interleavers 108-1 to N for transmission antennas (N _TX > 1), and spread multiplexing for several transmission antennas. Part 110-1 to N. Since each of the diffusion multiplexing units has the same configuration and function, the first one will be described on behalf of them. The diffusion multiplexing unit 110-1 includes a spreading unit 112, a multiplexing unit 114, a fast inverse Fourier transform unit 116, a guard interval insertion unit 118, and a spreading unit 132. Further, the transmitter includes a convolutional encoder 122, a QPSK modulation unit 124, a serial-parallel conversion unit 126, and several interleavers 128-1 to 128-N for transmission antennas.

  The turbo encoder 102 performs encoding to increase error tolerance of the transmitted data channel.

  The data modulator 104 modulates the data channel with an appropriate modulation scheme such as QPSK, 16QAM, 64QAM, or the like. When adaptive modulation and coding (AMC) is performed, the modulation scheme is changed as appropriate.

  The serial / parallel converter (S / P) 106 converts a serial signal sequence (stream) into a parallel signal sequence. The number of parallel signal sequences may be determined according to the number of transmission antennas and the number of subcarriers.

  Interleavers 108-1 to 108-N rearrange the order in which the data channels are arranged according to a predetermined pattern. The rearrangement is performed for each antenna in the illustrated example.

  Spreading multiplexing sections 110-1 to 110-N process the data channel for each antenna and output baseband OFCDM symbols, respectively. The spreading unit 112 performs code spreading by multiplying each of the parallel signal sequences by a predetermined spreading code. In this embodiment, two-dimensional spreading is performed, and a signal is spread in the time direction and / or the frequency direction.

  The same processing as that for the data channel is performed for the control channel. The convolutional encoder 122 performs encoding for increasing the error tolerance of the control information data. The QPSK modulator 124 modulates the control channel using the QPSK modulation method. Any suitable modulation method may be adopted, but since the amount of control information data is relatively small, in this embodiment, the QPSK modulation method with a small number of modulation multi-values is adopted. The serial / parallel converter (S / P) 126 converts a serial signal sequence into a parallel signal sequence. The number of parallel signal sequences may be determined according to the number of subcarriers and the number of transmission antennas. Interleavers 128-1 to 128-N rearrange the order in which the control channels are arranged according to a predetermined pattern. The spreading unit 132 performs code spreading by multiplying each of the parallel signal sequences by a predetermined spreading code.

  The multiplexing unit 114 multiplexes the spread data channel and the spread control channel. Multiplexing may be any of time multiplexing, frequency multiplexing, and code multiplexing. In the present embodiment, a pilot channel is input to the multiplexing unit 114 and is also multiplexed. In another embodiment, the pilot channel may be input to the serial / parallel converter 106 or 126, and the pilot channel may be frequency-multiplexed with the data channel or the control channel, as indicated by the broken-line arrows in the figure. The fast inverse Fourier transform unit 116 performs fast inverse Fourier transform on the signal input thereto, and performs OFDM modulation. The guard interval insertion unit 118 creates a symbol in the OFDM scheme by adding a guard interval to the modulated signal. As is well known, the guard interval is obtained by duplicating the beginning or end of the symbol to be transmitted.

  In addition, the positional relationship (106 and 108, 126 and 128) of a serial-parallel conversion part and an interleaver may be changed like FIG. In the example shown in FIG. 1, since signals are separated for each antenna by S / P and then interleaved by individual interleavers, rearrangement is performed in the category of signals transmitted from one antenna. On the other hand, as shown in FIG. 2, since the influence of the rearrangement by the interleaver 107 extends to a plurality of antennas, a larger interleaving effect can be expected.

  The data channel is encoded by the turbo encoder 102 in FIG. 1, modulated by the data modulation unit 104, parallelized by the serial-parallel converter 106, rearranged by the interleaver 108, and spread by the spreading unit 112 for each subcarrier component. Diffused. Similarly, the control channel is encoded, modulated, parallelized, interleaved, and spread for each subcarrier component. The spread data channel and control channel are multiplexed for each subcarrier by the multiplexing unit 114, modulated by the OFDM method by the fast inverse Fourier transform unit 116, a guard interval is added to the modulated signal, and the baseband OFCDM symbols are output for each antenna. The baseband signal is converted into an analog signal, orthogonally modulated by the orthogonal modulator 402 of the RF processing unit, appropriately amplified after band limitation, and wirelessly transmitted from each antenna. In this case, different signals are simultaneously transmitted from the antennas using the same radio resource. Radio resources can be distinguished by one or more of frequency, time and code. Therefore, the information transmission rate can be increased in proportion to the number of transmission antennas. In order to receive, demodulate and decode signals transmitted in this way, the receiving side (typically a mobile station) needs to know at least the number of transmission antennas (the number of transmission data sequences).

FIG. 3 shows a block diagram of a receiver that can be used in one embodiment of the present invention. This receiver is typically provided in a base station, but may be provided in a mobile station. The receiver has N _RX (> 1) reception antennas 502-1 to N _RX , and for each antenna, a low noise amplifier 504, a mixer 506, a local oscillator 508, a band pass filter 510, Automatic gain controller 512, quadrature detector 514, local oscillator 516, analog-digital converter 518, guard interval remover 522, fast Fourier transformer 524, demultiplexer 526, channel estimator 528, A despreading unit 530, a parallel-serial conversion unit (P / S) 532, and a despreading unit 534 are included. Since the processing elements and operations for each antenna are the same, the configuration and operation relating to one antenna will be described as a representative. The receiver also includes a symbol timing detection unit 520, a deinterleaver 536, a turbo encoder 538, and a Viterbi decoder 540.

  The low noise amplifier 504 appropriately amplifies the signal received by the antenna 502. The amplified signal is converted to an intermediate frequency by the mixer 506 and the local oscillator 508 (down-conversion). The band pass filter 510 removes unnecessary frequency components. The automatic gain control unit 512 controls the gain of the amplifier so that the signal level is properly maintained. The quadrature detector 514 uses the local oscillator 516 to perform quadrature demodulation based on the in-phase component (I) and quadrature component (Q) of the received signal. The analog / digital conversion unit 518 converts an analog signal into a digital signal.

  Symbol timing detection section 520 detects the timing of symbols (symbol boundaries) based on digital signals from each antenna.

  The guard interval removing unit 522 removes a portion corresponding to the guard interval from the received signal.

  The fast Fourier transform unit 524 performs fast Fourier transform on the input signal and performs demodulation of the OFDM method.

  The demultiplexer 526 separates a pilot channel, a control channel, and a data channel that are multiplexed in the received signal. This separation method is performed corresponding to multiplexing on the transmission side (contents of processing in the multiplexing unit 114 in FIG. 1).

  Channel estimation section 528 estimates the state of the propagation path using the pilot channel and outputs a control signal for adjusting the amplitude and phase so as to compensate for channel fluctuation. This control signal is output for each subcarrier.

Despreading section 530 despreads the data channel after channel compensation for each subcarrier. The code multiplexing number is assumed to be C _mux .

  The parallel / serial converter (P / S) 532 converts the parallel signal sequence into a serial signal sequence.

  The despreading unit 534 despreads the control channel after channel compensation.

  The deinterleaver 536 changes the order of signal arrangement according to a predetermined pattern. The predetermined pattern corresponds to the reverse pattern of the rearrangement performed by the transmitting interleaver (108 in FIG. 1).

  The turbo encoder 538 and the Viterbi decoder 540 decode the traffic information data and the control information data, respectively.

The signal received by the antenna is converted into a digital signal through processing such as amplification, frequency conversion, band limitation, and orthogonal demodulation in the RF receiver. The fast Fourier transform unit 524 performs OFDM demodulation on the digital signal from which the guard interval has been removed. The demodulated signal is separated into a pilot channel, a control channel, and a data channel by a separation unit 526. The pilot channel is input to the channel estimator, and a control signal that compensates for fluctuations in the propagation path is output for each subcarrier therefrom. The data channel is compensated using a control signal, despread for each subcarrier, and converted into a serial signal. The converted signals are rearranged in a predetermined pattern by the deinterleaver 536 and decoded by the turbo decoder 538. The predetermined pattern is a reverse pattern to the rearrangement performed by the interleaver. Similarly, the control channel is compensated for the channel variation by the control signal, despread, and decoded by the Viterbi decoder 540. Thereafter, signal processing using the restored data and the control channel is performed. In this case, each signal from each antenna on the transmitting side is derived from the received signal by some signal separation method. However, in order to properly demodulate and decode the received signal, the receiver needs to know at least the number of transmission antennas N _TX (the number of transmission data sequences).

  Examples of the signal separation method include a blast (BLAST) method, an MMSE method, and an MLD method. The blast method measures the reception level for each transmission antenna, performs decoding and determination in order from the transmission signal with the maximum level, estimates the interference signal (interference replica), and subtracts the interference replica from the reception signal to transmit sequentially Estimate the signal. In the least mean square error (MMSE) method, a MMSE weight is derived based on a channel gain from each transmission antenna, and a received signal is weighted and synthesized to obtain a transmitted signal. Maximum Likelihood Detection (MLD) method estimates the channel gain from each transmission antenna and selects a modulation candidate that minimizes the mean square error between the modulation candidate of the transmission data and the received signal. Estimate the signal. In the present invention, these and other signal separation methods may be used.

[MIMO Diversity]
FIG. 4 shows a block diagram of a MIMO diversity transmitter. Elements already described in FIG. 1 are denoted by the same reference numerals, and redundant description thereof is omitted. In FIG. 4, a transmission diversity coding unit 402 is depicted between the interleaver 108 and the code multiplexing unit 110. Transmission diversity coding section 402 adjusts the content and order of signals so that signals transmitted from the respective transmission antennas have a predetermined correspondence with each other. The transmission diversity coding unit 402 is also referred to as a space time transmission diversity (STTD) processing unit or an STTD encoder.

  FIG. 5 shows a block diagram of a MIMO diversity receiver. Elements already described in FIG. 3 are denoted by the same reference numerals, and redundant description thereof is omitted. In FIG. 5, a transmission diversity decoding unit 52 and a deinterleaver 54 are depicted. Based on the despread received signal and the channel estimation result, the coding unit 52 separates the received signal into signals from the transmitting antennas based on the transmission diversity. The separation method is determined depending on the processing contents performed by the transmission diversity coding unit on the transmission side. The deinterleaver 54 rearranges the decoded signals in a predetermined order. The predetermined order corresponds to a reverse pattern of the order applied by the transmission side interleaver.

FIG. 6 shows the contents before and after the signal processing performed by the transmitter of FIG. For simplicity, it is assumed that a sequence of four symbols indicated by S ₁ , S ₂ , S ₃ , and S ₄ is sequentially input to the turbo encoder 102 as a data channel. It is assumed that the number of transmission antennas is 2 (N _TX = 2). As shown in the figure, four symbols are transmitted from the first transmitting antenna in the order of S ₁ , S ₂ , S ₃ , S ₄ , as in the symbol sequence input to the encoder. Symbols such as −S ₂ ^* , S ₁ ^* , −S ₄ ^* , and S ₃ ^* are sequentially transmitted from the second transmitting antenna. The symbol “-” represents a negative sign, and the superscript “*” represents a conjugate complex number. The STTD encoder 402 selects a sequence such as S ₁ , S ₂ , S ₃ , S ₄ and a sequence such as -S ₂ ^* , S ₁ ^* , -S ₄ ^* , S ₃ ^* from the input symbol sequence. Are provided to the processing unit for each transmission antenna. Accordingly, the transmitter, the time _t 1 ~t a signal represented by _S 1 _-S ^{2 *} wirelessly transmit during _2, signal represented between times _t 2 ~t ₃ in _S 2 _{+ S} ^{1 *} wirelessly transmitting a signal expressed by _S 3 _-S ^{4 *} between times _t 3 ~t ₄ wirelessly transmits a signal represented by _S 4 _{+ S} ^{3 *} between times _t 4 ~t ₅ Wireless transmission is performed, and thereafter a similar composite signal is transmitted. In response, the receiver first receives a signal represented by R ₁ = S ₁ −S ₂ ^* , and at the next time receives a signal represented by R ₂ = S ₂ + S ₁ ^* , At the next time, a signal expressed by R ₃ = S ₃ -S ₄ ^* is received, then a signal expressed by R ₄ = S ₄ + S ₃ ^* is received, and thereafter a similar signal is received. The transmission diversity decoding unit 52 of the receiver obtains transmission symbols S ₁ and S ₂ based on a relational expression of R ₁ = S ₁ −S ₂ ^{* and} a relational expression of R ₂ = S ₂ + S ₁ ^*. . These relational expressions need to be grasped in advance by the receiver as a predetermined correspondence.

S ₁ = (R ₁ + R ₂ ^* ) / 2
S ₂ = (− R ₁ ^* + R ₂ ) / 2
Similarly, transmission symbols S ₃ and S ₄ can be obtained based on the received signals R ₃ and R ₄ .

In the example shown in FIG. 6, for the sake of simplicity, two transmission symbols are transmitted with a predetermined correspondence relationship, and a transmission symbol is obtained on the receiving side based on the correspondence relationship. More generally, however, some correspondence may be attached to more than two transmission symbols. Whatever correspondence is adopted, information having substantially the same content may be transmitted from two or more transmitting antennas during a certain period of time (in the above example, during the period from t _{1 to} t ₅ ). In addition, information substantially equal to S ₁ , S ₂ , S ₃ , S ₄ is transmitted from both the first and second transmission antennas). Thus, although the transmission diversity scheme does not increase the information transmission efficiency, the diversity effect increases as the number of transmission antennas increases, and the signal quality can be improved and the required transmission power can be reduced. As a result, it is possible to reduce the interference level given to the neighboring cells and consequently increase the system capacity. However, the receiver needs to know not only the number of transmission antennas but also the correspondence between the transmission symbols at least before demodulation.

[MIMO multiplexing and diversity]
FIG. 7 shows a conceptual diagram of a scheme in which the MIMO multiplexing scheme and the MIMO diversity scheme are combined. In FIG. 7, a data modulation unit 702, a serial-parallel conversion unit 704, a first transmission diversity unit 706-1, a second transmission diversity unit 706-2, and transmission antennas 711 to 722 are depicted. Yes.

  The data modulation unit 702 corresponds to the data modulation unit 104 in FIGS. 1 and 4, and the serial / parallel conversion unit 704 corresponds to the serial / parallel conversion unit 106 in FIGS.

  The first and second transmission diversity sections 706-1 and 706-2 have the same configuration and function as the transmission diversity coding section 402 in FIG. 4.

In operation, the data channel modulated by the data modulation unit 702 is divided into different symbol sequences by the serial / parallel conversion unit 704, and is sent to the first and second transmission diversity coding units 706-1 and 706 -2, respectively. Entered. For example, if the modulated symbol sequences are S ₁ , S ₂ , S ₃ , and S ₄ , S ₁ and S ₂ are input to the first transmission diversity coding unit 706-1, and S ₃ and S ₄ May be input to the second transmission diversity coding section 706-2. The first transmission diversity coding unit 706-1 duplicates the input symbols, creates two symbol sequences having a predetermined correspondence relationship, and transmits them from the transmission antenna. For example, S ₁ and S ₂ are wirelessly transmitted in order from the first transmission antenna 711, and −S ₂ ^* and S ₁ ^* are wirelessly transmitted from the second transmission antenna 712. Similarly, the second transmission diversity coding section 706-2 also duplicates the input symbols, creates two symbol sequences having a predetermined correspondence relationship, and transmits them from the transmission antenna. For example, S ₃ and S ₄ are wirelessly transmitted in order from the first transmission antenna 721, and −S ₄ ^* and S ₃ ^* are wirelessly transmitted from the second transmission antenna 722. As a result, the transmitter first wirelessly transmits S ₁ -S ₂ ^* + S ₃ -S ₄ ^*, and wirelessly transmits S ₂ + S ₁ ^* + S ₄ ^* + S ₃ ^* at the next time point.

The receiver first receives R ₁ = S ₁ −S ₂ ^* + S ₃ −S ₄ ^*, and receives R ₂ = S ₂ + S ₁ ^* + S ₄ ^* + S ₃ ^* at the next time point. The receiver performs some sort of signal separation based on the first received signal R ₁ and estimates a group of symbols transmitted from each of the four transmit antennas. As a result, it can be estimated that S ₁ , -S ₂ ^* , S ₃ , and -S ₄ ^* are transmitted from the four transmission antennas at the first time point. The receiver also performs some sort of signal separation based on the second received signal R ₂ and estimates a group of symbols transmitted from each of the four transmit antennas. As a result, it can be estimated that S ₂ , S ₁ ^* , S ₄ ^* , and S ₃ ^* are transmitted from the four transmitting antennas at the next time point. Since these two types of groups of symbols have substantially the same content (they have different signs or are complex conjugate numbers), the receiver uses these four symbols S ₁ and S ₁ after using them. ₂ , S ₃ , S ₄ can be estimated with high accuracy. The number of transmission antennas, the number of parallel signal sequences, the diversity coding method, and the like may be variously changed in addition to the above.

[channel]
Various channels can be transmitted on the uplink or the downlink using the above-described MIMO multiplexing method, MIMO diversity method, and a combination thereof. However, an increase in communication capacity, speed, quality, etc. are mainly required in the downlink. In the downlink, (D1) common control channel, (D2) associated control channel, (D3) shared packet data channel, and (D4) dedicated packet data channel are transmitted as channels including traffic data. In the uplink, (U1) common control channel, (U2) associated control channel, (U3) shared packet data channel, and (U4) dedicated packet data channel are transmitted as channels including traffic data. In the downlink and uplink, a pilot channel not including traffic data is also transmitted as necessary. The pilot channel includes known signals that are known in advance on the transmission side and the reception side, and is particularly used for propagation path estimation and the like.

  (D1) The downlink common control channel includes a broadcast channel (BCH), a paging channel (PCH), and a downlink access channel (FACH). The common control channel includes control information related to processing at a relatively higher layer such as link setting and call control.

  (D2) The associated control channel includes control information related to processing in a relatively low layer and includes information necessary for demodulating the shared packet data channel. The necessary information may include, for example, a packet number, a modulation scheme, a coding scheme, a transmission power control bit, a retransmission control bit, and the like.

  (D3) The shared packet data channel is a high-speed radio resource shared between a plurality of users. Radio resources may be distinguished by frequency, code, transmission power, and the like. The sharing of radio resources may be performed using time division multiplexing (TDM), frequency division multiplexing (FDM), and / or code division multiplexing (CDM). A specific mode of multiplexing will be described later with reference to FIGS. In order to realize high-quality data transmission, an adaptive modulation and coding (AMC) method, an automatic repeat request (ARQ) method, or the like is employed.

  (D4) The dedicated packet data channel is a radio resource dedicated to a specific user. Radio resources may be distinguished by frequency, code, transmission power, and the like. In order to realize high quality data transmission, an adaptive modulation and coding (AMC) system, an automatic retransmission (ARQ) system, or the like is employed.

  (U1) The uplink common control channel includes a random access channel (RACH) and a reserved channel (RCH). The common control channel includes control information related to processing at a relatively higher layer such as link setting and call control.

  (U2) The associated control channel includes control information related to processing in a relatively low layer, and includes information necessary for demodulating the shared packet data channel. The necessary information may include, for example, a packet number, a modulation scheme, a coding scheme, a transmission power control bit, a retransmission control bit, and the like.

  (U3) The shared packet data channel is a high-speed radio resource shared between a plurality of users. Radio resources may be distinguished by frequency, code, transmission power, and the like. The sharing of radio resources may be performed using time division multiplexing (TDM), frequency division multiplexing (FDM), and / or code division multiplexing (CDM).

  (U4) The dedicated packet data channel is a radio resource dedicated to a specific user. Radio resources may be distinguished by frequency, code, transmission power, and the like. In order to realize high quality data transmission, an adaptive modulation and coding (AMC) system, an automatic retransmission (ARQ) system, or the like is employed.

[Transmission on the downlink]
Hereinafter, a transmission method of each channel in the downlink will be described. Since the common control channel includes broadcast information such as a cell number, it must be received by all mobile stations. In order to respond easily to this request, it is conceivable to transmit a common control channel from one transmission antenna as shown in FIG. 8 among a plurality of transmission antennas provided in the base station. In this case, the other transmit antennas are not used to transmit that channel. As described above, additional information such as the number of transmission antennas is required to properly demodulate a signal transmitted by the MIMO multiplexing method or the MIMO diversity method. For example, the received signal can be immediately demodulated without requiring such information. On the other hand, since the common control channel includes information related to call control and the like, it is desired that communication be performed reliably rather than speeding up. From such a viewpoint, it is desirable to give additional information such as the number of transmission antennas to the mobile station by some method and transmit the common control channel by the MIMO diversity method.

  Similarly, the associated control channel may be transmitted from one of a plurality of transmission antennas, or may be transmitted in a MIMO diversity scheme. Alternatively, the same content may be transmitted simultaneously from a plurality of transmission antennas.

Similarly, the data channel may be transmitted from one of a plurality of transmission antennas, or may be transmitted in a MIMO diversity scheme. The data channel is transmitted according to the performance of the mobile station by the base station in a state where the link is established. Therefore, the data channel may be transmitted by the MIMO multiplexing method, or may be transmitted by a combination method of the MIMO diversity method and the MIMO multiplexing method. The transmission rate can be improved by using the MIMO multiplexing method at least partially.
[Transmission / reception via uplink and downlink]
Based on the received common control channel, the mobile station acquires information on the number of transmission antennas of the base station, transmission methods of various channels, and the like.

  When the common control channel is transmitted from one transmission antenna, the mobile station can immediately demodulate the received common control channel. Thereby, the contents of BCH, PCH, and FACH can be grasped. The mobile station transmits information on the performance of the mobile station (number of reception antennas, number of transmission antennas, etc.), requested service (requested transmission rate), etc. to the base station using the uplink common control channel (RACH). To do. The base station notifies the mobile station of the transmission method (number of transmission antennas, etc.) of the associated control channel using the downlink common control channel (FACH). The transmission method of the data channel may be notified to the mobile station through a common control channel (FACH), or may be notified to the mobile station through an associated control channel. In the latter case, in addition to the modulation scheme and coding rate related to the transmission slot of each mobile station, the transmission method (MIMO multiplexing scheme, MIMO diversity scheme, combination thereof) is notified to the mobile station.

  Next, consider a case where the common control channel is transmitted by the MIMO diversity method. In this case, it is assumed that the MIMO diversity coding method (for example, the number of transmission antennas is two and a signal is transmitted with the processing contents as shown in FIG. 6) is known to the mobile station. To do. If all base stations are transmitting in the same MIMO diversity scheme, the mobile station extracts necessary information from the received common control channel based on such a prior arrangement, Processing can proceed. However, older base stations with only one transmit antenna may exist in some regions. In such a case, even if an attempt is made to demodulate a signal by the MIMO diversity method, it cannot be demodulated well. The mobile station of this embodiment tries to demodulate the common control channel by both of the two types of schemes. One of the two types is a demodulation method when a common control channel is transmitted from one transmission antenna, and the other is a demodulation method when it is transmitted by the MIMO diversity method. Of these two methods, necessary information is extracted from a channel that has been successfully demodulated. The order of demodulating in both systems may be simultaneous, or either one may be performed first. Thereafter, the same processing as described above is performed. That is, the mobile station uses the uplink common control channel (RACH) to transmit information on the mobile station performance (number of reception antennas, number of transmission antennas, etc.), requested service (requested transmission rate), etc. Send to. The base station notifies the mobile station of the transmission method (number of transmission antennas, etc.) of the associated control channel using the downlink common control channel (FACH).

  As described above, the pilot channel is used for purposes such as estimating a propagation path. In the MIMO scheme, since the propagation path is different for each transmission antenna, the pilot channel needs to be transmitted while being distinguished for each transmission antenna. Therefore, when the pilot channel, the control channel, and the data channel are multiplexed and transmitted from the transmitter, the pilot channel needs to be distinguished for each transmission antenna. In the following, various examples relating to multiplexing of pilot channels are shown, but it should be noted that they are exemplary and not listed in a limited way.

  FIG. 9 shows an example of multiplexing when a signal is transmitted from one of the plurality of transmission antennas. The control channel is not shown for simplicity. In this case, there is only one transmission antenna that transmits a signal. FIG. 9A shows a state where the pilot channel and the data channel are time-multiplexed. FIG. 9B shows a state where the pilot channel and the data channel are frequency-multiplexed.

  FIG. 10 is a diagram (part 1) illustrating a state in which pilot channels transmitted from four transmission antennas are multiplexed while being distinguished. The pilot channel and the data channel are time multiplexed. FIG. 10A shows a state in which pilot channels related to four transmission antennas # 1 to # 4 are time-multiplexed. FIG. 10B shows a state where pilot channels for four transmission antennas are code-multiplexed. In either case, since pilot channels are continuously inserted along the frequency direction, frequency diversity effect can be improved by performing interleaving in the frequency direction. FIG. 10C shows a conceptual diagram of signals transmitted from the first and second transmission antennas. As shown in the figure, the pilot channels transmitted from the first transmission antenna are distinguished by codes consisting of 1, 1, 1, 1 and the pilot channels transmitted from the second transmission antenna are 1, 1 , -1, and -1 are shown. These codes are examples and any suitable orthogonal pattern may be used.

  FIG. 11 is a diagram (part 2) illustrating a state in which pilot channels transmitted from four transmission antennas are multiplexed while being distinguished. The pilot channel and the data channel are time multiplexed. FIG. 11A shows a state where pilot channels for four transmission antennas are frequency-multiplexed. Such a method is preferable from the viewpoint of easily and satisfactorily performing channel estimation for each subcarrier. FIG. 11B shows a state where pilot channels for four transmission antennas are code-multiplexed. FIG. 11C shows a state where pilot channels for four transmission antennas are frequency-multiplexed and code-multiplexed. The code length can be shortened compared to the case where four are code-multiplexed. In any of the cases (A), (B), and (C), the transmission efficiency of information can be improved by using multiplexing in the frequency domain. In the example shown in FIG. 10, since multiplexing is performed in the time direction, when the number of symbols transmitted within one transmission time interval (TTI) is small, only a part of the resources prepared for the maximum number of symbols is used. The resource usage efficiency becomes low.

  FIG. 12 is a diagram (No. 3) illustrating a state of multiplexing while distinguishing pilot channels transmitted from four transmission antennas. The pilot channel and the data channel are frequency multiplexed. FIG. 12A shows a state in which time multiplexing is performed for each transmission antenna in the pilot channel. FIG. 12B shows a state where code multiplexing is performed for each transmission antenna in the pilot channel. FIG. 12C shows a state in which time multiplexing and code multiplexing are performed for each transmission antenna in the pilot channel. In general, since the fluctuation in the time direction is small, the orthogonality between the transmission antennas of the pilot channel can be maintained well.

  Hereinafter, the means taught by the present invention will be listed as an example.

(Section 1)
A transmitter that simultaneously transmits different signals from each of a plurality of antennas,
Pilot multiplexing means for multiplexing pilot channels transmitted from each antenna in one or more of time division multiplexing, frequency division multiplexing, and code division multiplexing;
Data multiplexing means for time-multiplexing the pilot channel and the data channel;
Means for transmitting a signal in at least one of a space division multiplexing (SDM) scheme and a space-time transmission diversity (STTD) scheme;
A transmission device comprising:

(Section 2)
The transmission apparatus according to claim 1, wherein pilot channels transmitted from each antenna are multiplexed by frequency division multiplexing or code division multiplexing, regardless of time division multiplexing.

(Section 3)
The transmission apparatus according to claim 1, wherein the means for transmitting the signal performs transmission by an orthogonal frequency code division multiplexing (OFCDM) system.

(Section 4)
Serial-parallel conversion means for distributing a signal sequence to be transmitted to each of the antennas;
4. The transmission apparatus according to claim 3, further comprising interleaving means for changing the arrangement of signals in one or more output signal sequences of the serial-parallel conversion means.

(Section 5)
Serial-parallel conversion means for distributing a signal sequence to be transmitted to each of the antennas;
4. The transmission apparatus according to claim 3, further comprising interleaving means for changing the arrangement of signals in the input signal series of the serial-parallel conversion means.

(Section 6)
A receiving device that receives signals transmitted from each of a plurality of transmitting antennas simultaneously by a plurality of receiving antennas,
Data separation means for separating the time-multiplexed pilot channel and data channel;
Pilot demultiplexing means for demultiplexing a pilot channel for each transmit antenna multiplexed in one or more of time multiplexing, frequency multiplexing, and code multiplexing;
Means for demodulating a signal transmitted and received from one antenna;
Means for demodulating a signal in a space-time transmit diversity (STTD) scheme;
A receiving apparatus comprising:

(Section 7)
A transmission method for simultaneously transmitting different signals from each of a plurality of antennas,
Multiplexing pilot channels transmitted from each antenna in one or more of time division multiplexing, frequency division multiplexing, and code division multiplexing,
Time-multiplexing the pilot and data channels;
A transmission method characterized by transmitting signals from one antenna or from a plurality of antennas by a space-time transmission diversity (STTD) method.

(Section 8)
A reception method for receiving signals simultaneously transmitted from each of a plurality of transmission antennas by a plurality of reception antennas,
Separating the time-multiplexed pilot channel and data channel;
Separating a pilot channel for each transmit antenna multiplexed in one or more of time multiplexing, frequency multiplexing, and code multiplexing;
A receiving method characterized by demodulating a signal by both a method for demodulating a signal transmitted from one antenna and a space-time transmission diversity (STTD) method.

102 turbo encoder; 104 data modulation unit; 106, 107 serial-parallel conversion unit; 108-1 to N, 105 interleaver; 110-1 to N spreading multiplexing unit 110-1 to N; 112 spreading unit; 114 multiplexing unit; 116 Fast Inverse Fourier Transform; 118 Guard Interval Insertion; 122 Convolutional Encoder; 124 QPSK Modulation; 126 Series-Parallel Conversion; 128-1 to N; 132 Spreading;
502-1 to N receiving antenna; 504 low noise amplifier; 506 mixer; 508 local oscillator; 510 band pass filter; 512 automatic gain control unit; 514 quadrature detector; 516 local oscillator; 518 analog-digital conversion unit; 522 Guard interval removal unit 524 Fast Fourier transform unit; 526 Demultiplexer; 528 Channel estimation unit; 530 Despreading unit; 532 Parallel-serial conversion unit (P / S); 534 Despreading unit; 536 Deinterleaver; 540 Viterbi decoder;
402 transmit diversity coding section;
52 transmission diversity decoding unit; 54 deinterleaver;
702 Data modulation unit; 704 Series-parallel conversion unit; 706-1, 2 Transmit diversity coding unit; 711, 712, 721, 722 Transmit antenna

Claims (1)

A transmitter that simultaneously transmits different signals from each of a plurality of antennas,
Pilot multiplexing means for multiplexing pilot channels transmitted from each antenna in one or more of time division multiplexing, frequency division multiplexing, and code division multiplexing;
Data multiplexing means for time-multiplexing the pilot channel and the data channel;
Means for transmitting a signal in at least one of a space division multiplexing (SDM) scheme and a space-time transmission diversity (STTD) scheme;
A transmission device comprising:

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