JP5015211B2 - Transmission device, transmission method, reception device, and reception method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission apparatus which keeps a transmission efficiency, even if the number of symbols contained in TTI are few. <P>SOLUTION: The transmission apparatus includes a multiplex means which multiplexes a common pilot channel, a holding-in-common control channel and a holding-in-common data channel, a means which carries out an inverse Fourier transformation on the multiplexed signal to produce a symbol, and a means which transmits the produced symbol. The multiplex means multiplexes for a frequency a holding-in-common control channel which is used in demodulation of the holding-in-common data channel containing a payload and a common pilot channel which is used in the demodulation of the holding-in-common and is used in a plurality of users in common, and multiplexes for time the common pilot channel, the holding-in-common control channel, and the holding-in-common data channel. The reduction in the number of symbols constituting TTI (a term of one symbol become longer) makes insertion frequency of the common pilot fewer, corresponding to it, thereby the transmission efficiency of the channel other than the common pilot channel can be maintained. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention generally relates to the technical field of mobile communication, and more particularly to a transmission apparatus, a transmission method, a reception apparatus, and a reception method used in an orthogonal frequency division multiplexing (OFDM) mobile communication system.

  In future mobile communication systems where video communication and data communication are mainly performed, the ability to surpass the conventional mobile communication system (IMT-2000) is required, and it is necessary to sufficiently achieve high capacity, high speed, broadband, etc. There is. In a broadband mobile communication system, the influence of frequency selective fading due to the multipath propagation environment becomes significant, and therefore, the OFDM scheme is regarded as a promising next generation communication scheme. In the OFDM method, a symbol is formed by adding a guard interval portion to an effective symbol portion including information to be transmitted, and a plurality of symbols are transmitted at every predetermined transmission time interval (TTI). One frame includes a predetermined number of TTIs. The guard interval part is created by a part of information included in the effective symbol part. The guard interval part is also called a cyclic prefix (CP). FIG. 1 shows the interrelationship of frames, TTIs and symbols. On the receiving side, paths having various propagation delays are received. However, in the OFDM scheme, intersymbol interference can be effectively suppressed if the propagation delay is within the guard interval period.

  Various channels are transmitted during one TTI, and the channels may include a common pilot channel, a shared control channel, and a shared data channel. The common pilot channel is used to demodulate the shared control channel and is commonly used by a plurality of users. Specifically, the common pilot channel is used for channel estimation, synchronous detection, reception signal quality measurement, and the like. The shared control channel is used to demodulate the shared data channel that includes the payload (or traffic information channel). A conventional signal format including a pilot channel is described in Non-Patent Document 1, for example.

Supervised by Keiji Tachikawa, “W-CDMA mobile communication system”, Maruzen Co., Ltd. 100-101

  By the way, the transmission time interval (TTI) defines various units in information transmission. For example, a packet transmission unit, a data modulation scheme in MCS (Modulation and Coding Scheme), a channel coding rate update unit, and error correction coding. The TTI length and the frame length should be kept constant, because the unit of T, the retransmission unit in automatic repeat control (ARQ: Automatic Repeat reQuest), the unit of packet scheduling, and the like are determined by the TTI. However, the number of symbols included in the TTI may be subject to change as appropriate depending on the application or the system.

  On the other hand, in conventional transmission schemes of various channels, a common pilot is assigned to one or more symbols in a TTI, and a control channel or a data channel is assigned to other symbols in the TTI. For example, when the TTI is composed of 10 symbols, it is assumed that one symbol is occupied by the common pilot channel. In this case, the common pilot channel occupies 1/10 = 10% of the TTI. On the other hand, it is assumed that the TTI is composed of 5 symbols, and 1 symbol is occupied by the common pilot channel. In this case, the common pilot channel occupies 1/5 = 20% of the TTI. Therefore, when the number of symbols included in the TTI is reduced, there arises a problem that the transmission efficiency of the data channel is lowered. Such a tendency becomes more prominent as the number of symbols in the TTI decreases.

  The present invention has been made to address the above-described problems, and the problem is that a transmission apparatus, a transmission method, and a reception that maintain or improve the transmission efficiency of a data channel even when the number of symbols included in the TTI is small. An apparatus and a receiving method are provided.

  In the present invention, multiplexing means for multiplexing the common pilot channel, the shared control channel and the shared data channel, means for generating a symbol by performing inverse Fourier transform on the multiplexed signal, and means for transmitting the generated symbol Are used. The multiplexing means multiplexes the common control channel used for demodulating the shared data channel including the payload and the common pilot channel used for demodulating the shared control channel and commonly used by a plurality of users in the frequency direction. The pilot channel, the shared control channel, and the shared data channel are multiplexed in the time direction.

  According to the present invention, the transmission efficiency of the data channel can be maintained or improved even when the number of symbols included in the TTI is small.

It is a figure which shows the correlation of a frame, TTI, and a symbol. 1 shows a block diagram of a transmitter according to one embodiment of the present invention. FIG. 1 shows a block diagram of a receiver according to one embodiment of the present invention. FIG. It is a figure which shows the example of a channel structure in one Example of this invention. It is a figure which shows the example of various channel structures. It is a figure which shows the example of various channel structures containing a dedicated pilot channel. It is a figure which shows the correlation of an insertion space | interval, symbol length, and maximum delay time. 1 shows a block diagram of a transmitter according to one embodiment of the present invention. FIG. It is a figure which shows the example of a channel structure in one Example of this invention. 1 shows a block diagram of a transmitter according to one embodiment of the present invention. FIG. It is a figure which shows a sector beam and a directional beam. It is a figure which shows the example of a channel structure in one Example of this invention. It is a figure which shows a mode that the MIMO multiplexing method by one Example of this invention is performed. It is a figure which shows the example of a channel structure in one Example of this invention. It is a figure which shows the various channel structure examples regarding a common pilot channel. It is a figure which shows the structural example of a common / dedicated pilot channel. The conceptual diagram of the pilot channel transmitted by multi-beam is shown. The conceptual diagram of the pilot channel transmitted with an adaptive directed beam is shown. It is a figure which shows the example which allocates a common and a dedicated pilot channel with a TDM system. Is a diagram showing the throughput and relationship of the average received E _{s /} N ₀ in the case of changing the static number guard mapping. It is a figure which shows the example of a channel mapping with respect to the number of staggered mapping _Nstg = 0,1,2. It is a figure which shows a mode that the pilot sequence orthogonal between sectors is used. 3 shows a pilot channel generator used in a transmitter according to an embodiment of the present invention. It is a figure which shows the specific example of an orthogonal pilot sequence. It is a figure which shows the specific example of an orthogonal pilot sequence. It is a figure which shows the example of correspondence of a scramble code and an orthogonal code. It is a figure which shows the example (the 1) which multiplies a common pilot channel and another channel by a scramble code and an orthogonal code. It is a figure which shows the example (the 2) which multiplies a common pilot channel and another channel by a scramble code and an orthogonal code. It is a figure which shows a mode that the example shown by FIG.25 and FIG.26 was combined. It is a figure which shows the pilot channel and data channel of a desired signal and an undesired signal. It is a figure which shows the orthogonal sequence between sectors with respect to the pilot channel for MIMO. It is a figure for demonstrating the property of a Kazak code. It is a figure which shows the pilot channel and data channel of a desired signal and an undesired signal.

  According to one aspect of the invention, the common pilot channel and the shared data channel are time multiplexed, and the shared control channel and the data channel are also time multiplexed. Since the common pilot channel is not assigned to all frequency bands in the symbol but only to some frequency bands or some subcarriers, assign a channel other than the common pilot channel to other subcarriers in the symbol. Can do. By adjusting the insertion position of the common pilot channel in the frequency direction, the proportion of the common pilot channel in the TTI can be adjusted. Therefore, if the number of symbols constituting the TTI decreases (the period of one symbol becomes longer), the transmission efficiency of channels other than the common pilot channel is at least maintained by reducing the insertion frequency of the common pilot channel accordingly. be able to.

  In one form of the present invention, the dedicated pilot channel used for demodulation of the shared control channel and used for one or more specific users, and the common pilot channel and the shared control channel are multiplexed in the time direction. By performing channel estimation using the dedicated pilot channel in addition to the common pilot channel, the channel estimation accuracy and the like can be improved.

  The dedicated pilot channel may be time-multiplexed at the first time at a constant frequency interval, and may be time-multiplexed at the constant frequency interval at the second time. By distributing the pilot channel in both time and frequency directions, the diversity effect of the pilot channel can be improved while improving the transmission efficiency of channels other than the pilot channel.

  The dedicated pilot channel is transmitted to a communication partner moving at high speed, but may not be transmitted to a communication partner not moving at high speed. By transmitting the dedicated pilot channel only to users with large channel fluctuations in the time direction, it is not necessary to transmit it unnecessarily.

  Means for adjusting the directivity of the transmission beam to a specific communication partner may be provided in the transmission apparatus. The dedicated pilot channel may be inserted for each specific communication partner. When a directional beam is used, the channel condition differs for each beam. In addition to the common pilot channel, channel estimation accuracy can be improved by using a dedicated pilot channel specialized in that direction.

  When MIMO multiplexing is used, the common pilot channel may be transmitted from one or more transmission antennas, and the dedicated pilot channel may be transmitted from another one or more transmission antennas. Thereby, it is possible to perform appropriate MIMO multiplexing transmission according to the class of the receiving device (specifically, the number of receiving antennas).

  In one aspect of the present invention, a means for receiving a symbol transmitted from a transmission apparatus, a means for Fourier transforming the received symbol, and a common pilot channel, a shared control channel, and a shared data channel are separated from the signal after the Fourier transform. A receiving device having separating means is used. The separating means frequency-separates a common pilot channel used for demodulating the shared control channel and commonly used by a plurality of users and a shared control channel used for demodulating the shared data channel, and separates the common pilot channel and the shared control channel. And the shared data channel containing the payload are time separated.

  In an OFDM transmission apparatus according to an aspect of the present invention, a common pilot channel is multiplied by a spreading code sequence (scramble code) common to a plurality of sectors and a different orthogonal code sequence for each sector, which is a communication partner (typical). To the mobile station). Since each sector is distinguished not by a scramble code but by an orthogonal code, the sector can be discriminated easily and with high accuracy, and the quality of the pilot channel can be improved.

  Channels other than the common pilot channel may be multiplied by a spread code sequence common to a plurality of sectors and an orthogonal code sequence that is different for each sector.

  Another spreading code sequence may be derived from a spreading code sequence common to a plurality of sectors according to a predetermined rule, and a channel other than the pilot channel may be multiplied by the derived spreading code sequence. As a result, both scramble codes can be quickly detected by using the derivation rule while using different scramble codes for the pilot channel and other channels.

  A spreading code sequence common to a plurality of sectors and an orthogonal code sequence different for each sector may be multiplied by the common pilot channel and the shared control channel, and another spreading code sequence may be multiplied by the shared data channel. Thereby, for example, the scramble code can be used properly from the viewpoint of whether or not the spreading factor varies.

  In the following embodiments, a system employing the OFDM scheme is used for the downlink, but the present invention may be used for other multi-carrier scheme systems.

  FIG. 2 shows a portion of a transmitter according to one embodiment of the present invention. This transmitter is typically provided in a radio base station of a mobile communication system as in the present embodiment, but may be provided in other devices. The transmitter includes K data channel processing units 202-1 to 202-1 to K, a common pilot multiplexing unit 204, an IFFT unit 206, and a guard interval insertion unit 208. Since the configuration and function of each of the data channel processing units are the same, the first data channel processing unit 202-1 will be described as a representative thereof. The data channel processing unit 202-1 includes a spreading and channel encoding unit 210, an interleaving processing unit 212, a data modulation unit 214, and a time and frequency mapping unit 216.

  The data channel processing unit 202-1 processes a data channel related to the first user. For convenience of explanation, one data channel processing unit is illustrated to perform processing related to one user, but processing for one user may be performed by a plurality of data channel processing units.

  The spreading and channel coding unit 210 performs channel coding of a data channel to be transmitted to improve error correction capability. In this embodiment, communication is performed using the OFDM method, and code spreading is not performed. However, in another embodiment, communication is performed by the OFCDM system, and the spreading and channel coding unit 210 code spreads the data channel to be transmitted and also performs channel coding. Channel coding may be performed by, for example, turbo coding.

  Interleaving processing section 212 changes the arrangement of symbols in the time direction and / or frequency direction of the signal after channel coding according to a known rule on both sides of transmission and reception.

  The data modulation unit 214 maps the transmitted signal to a signal constellation diagram (signal constellation) according to an appropriate modulation scheme. For example, various modulation schemes such as QPSK, 16QAM, and 64QAM may be used. When adaptive modulation and coding (AMC) is performed, a modulation scheme and a channel coding rate are designated each time.

  The time and frequency mapping unit 216 determines how to map the transmitted data channel in the time direction and / or the frequency direction.

  The common pilot multiplexing unit 204 multiplexes and outputs the common pilot channel, the shared control channel, and the data channel. Multiplexing may be done in the time direction, frequency direction or both time and frequency directions.

  The IFFT unit 206 performs high-speed inverse Fourier transform on the signal to be transmitted, and performs OFDM modulation. Thereby, an effective symbol part is formed.

  The guard interval insertion unit 208 extracts a part of the effective symbol part and adds it to the beginning or end of the effective symbol part, thereby creating a transmission symbol (transmission signal).

  The data channel transmitted to each user is processed by each of the data channel processing units 202-1 to 202-K. Within the data channel processor, the data channel is channel coded, interleaved, data modulated, and time / frequency mapping is determined. The outputs from each of the data channel processing units 202-1 to 202-1K are multiplexed with the common pilot channel and the shared control channel by the common pilot multiplexing unit 204. The multiplexed signal is subjected to fast inverse Fourier transform, and a guard interval is added to the converted signal (effective symbol part) to create a transmission symbol. The transmission symbol is wirelessly transmitted through a wireless unit (not shown).

  FIG. 3 shows part of a receiver according to an embodiment of the invention. Such a receiver may typically be provided in a mobile station (for example, a communication device of user # 1) of the mobile communication system as in the present embodiment, but may be provided in another device. The receiver includes a guard interval removal unit 302, an FFT unit 304, a common pilot separation unit 306, a channel estimation unit 308, an individual pilot separation unit 310, a time and frequency data extraction unit 312, and a data demodulation unit 314. A deinterleave processing unit 316 and a despreading and channel decoding unit 318.

  The guard interval removal unit 302 removes the guard interval part from the transmission symbol and extracts an effective symbol part.

  The FFT unit 304 performs fast Fourier transform on the signal to perform OFDM demodulation.

  The common pilot separation unit 306 separates the common pilot channel, the shared control channel, and other channels from the signal for each subcarrier demodulated by the OFDM method.

  Channel estimation section 308 performs channel estimation using the separated common pilot channel, and provides a control signal for channel compensation to data demodulation section 314 and the like. Such control signals are also used for channel compensation of the shared control channel, although not shown in detail for simplicity of illustration.

  The dedicated pilot separation unit 310 is not used in the present embodiment, but separates the dedicated pilot channel from other channels in the embodiment described later. The dedicated pilot channel is given to the channel estimator and is used to improve channel estimation accuracy.

  The time and frequency data extraction unit 312 extracts and outputs a data channel according to the mapping rule determined on the transmission side.

  The data demodulator 314 performs channel compensation on the data channel and performs demodulation. The demodulation method is performed in accordance with the modulation method performed on the transmission side.

  The deinterleave processing unit 316 changes the arrangement of symbols in accordance with the interleaving performed on the transmission side.

  The despreading and channel decoding unit 318 performs channel decoding of the received data channel. In this embodiment, communication is performed using the OFDM method, and code despreading is not performed. However, in another embodiment, communication is performed by the OFCDM method, and the data channel received by the despreading and channel decoding unit 318 is code despread and channel decoding is also performed.

  The signal received by the antenna is converted to baseband via a radio unit (not shown), the guard interval is removed, and fast inverse Fourier transform is performed. A common pilot channel is separated from the converted signal, and channel estimation is performed. Further, the shared control channel and the data channel are separated from the converted signal and demodulated respectively. The demodulated data channel is deinterleaved, channel decoded, and the transmitted data is recovered.

FIG. 4 shows how various channels are multiplexed in this embodiment. As an example, in this embodiment, 20 TTIs are included in a 10 ms frame (in this case, 1 TTI is 0.5 ms). One TTI is composed of seven symbols arranged in the time direction (N _D = 7).

  In the illustrated example, a common pilot channel, a shared control channel, a dedicated pilot channel, and a data channel are multiplexed. The dedicated pilot channel will be described in the second and subsequent embodiments. The common pilot channel and the shared control channel are frequency-multiplexed in one symbol. More specifically, the common pilot channel is inserted at a constant frequency interval in the head symbol in the TTI. The shared data channel is transmitted by the second and subsequent symbols in the TTI. That is, the common pilot channel and the shared data channel are time multiplexed, and the shared control channel and the data channel are also time multiplexed. Since the common pilot channel is not assigned to all frequency bands in the symbol but only to some frequency bands or some subcarriers, assign a channel other than the common pilot channel to other subcarriers in the symbol. Can do. By adjusting the insertion position of the common pilot channel in the frequency direction, the proportion of the common pilot channel in the TTI can be adjusted. Therefore, if the number of symbols constituting the TTI decreases (the period of one symbol becomes longer), the transmission efficiency of channels other than the common pilot channel is at least maintained by reducing the insertion frequency of the common pilot channel accordingly. be able to.

  FIG. 5 shows various channel configuration examples for multiplexing the common pilot channel and the shared control channel. The channel configuration is not limited to that shown, and various configurations can be used. Channel configuration example 1 is the same as that shown in FIG. As described above, the common pilot channel is used for channel estimation for demodulating the shared control channel. In channel configuration example 1, since the common pilot channel and the shared control channel are frequency-multiplexed and there is no common pilot channel for the subcarrier in which the shared control channel is inserted, channel estimation values for the shared control channel can be obtained directly. I can't. In this channel configuration example, the channel estimation value for the shared control channel is derived by interpolating the channel estimation value of the subcarrier in which the common pilot channel is inserted. For the interpolation, for example, linear interpolation may be used. In the figure, a bidirectional arrow means that interpolation is performed in that section. In this example, since the common pilot channel and the shared control channel are all obtained with the first symbol, the shared data channel can be quickly demodulated. In addition, since the common pilot channel and the shared control channel are widely dispersed in the frequency direction, the frequency diversity effect is increased, and the resistance to frequency selective fading can be increased.

  In channel configuration example 2, the common pilot channel and the shared control channel are time-multiplexed. In this example, channel estimation values need not be interpolated as in channel configuration example 1. Since the common pilot channel and the shared control channel are widely dispersed in the frequency direction, it is possible to increase resistance to frequency selective fading.

  In channel configuration example 3, the shared control channel is time-multiplexed after some common pilot channels and is not inserted after another common pilot channel. Since the common pilot channel and the shared control channel are multiplexed in the time direction, they can be transmitted while adjusting their power ratio. In this example, the shared control channel is inserted over almost the entire period of the TTI, so a channel estimate over the entire period is required. In this case, if only the common pilot channel of the first symbol is used, channel estimation accuracy for the last symbol may not be sufficiently ensured. This is because the channel fluctuation in the time direction is large particularly when moving at high speed. For this reason, it is desirable that channel estimation is performed using both the channel estimation value of the leading symbol in the TTI and the channel estimation value of the leading symbol of the subsequent TTI (for example, by linearly interpolating them).

  In channel configuration example 4, the shared control channel is multiplexed with a time and frequency bidirectional hopping pattern. Since the common pilot channel and the shared control channel are widely dispersed in the frequency direction, it is possible to increase resistance to frequency selective fading. Since the common pilot channel and the shared control channel are distributed in the time direction, transmission can be performed while adjusting their power ratio.

  In the second embodiment of the present invention, a dedicated pilot channel is also used in addition to the common pilot channel. These channels are common in that they are used for channel estimation and the like, but the former is commonly used for all mobile stations, and the latter is different in that it is used only for a specific mobile station. Therefore, one type of signal representing the common pilot channel may be used, but the number of signals representing the dedicated pilot channel should be prepared more than the number of mobile stations. The dedicated pilot channel is used when the mobile station moves at high speed, when a directional beam is used in the downlink, when the mobile station has a predetermined number of receiving antennas, etc. It will be described later.

  FIG. 6 shows various channel configuration examples including dedicated pilot channels. The channel configuration is not limited to that shown, and various configurations can be used. In channel configuration example 1, dedicated pilot channels are inserted at constant frequency intervals in the second symbol. In channel configuration example 2, the dedicated pilot channel is inserted in a pattern that hops in both time and frequency directions. In channel configuration example 3, the dedicated pilot channel is time-multiplexed after some common pilot channels and is not inserted after another common pilot channel. In channel configuration example 4, the dedicated pilot channel and the shared data channel are code-multiplexed.

Relates common pilot channels and the dedicated pilot channels, when the channel estimation in the time domain is performed, insertion interval delta _P of the pilot channel is required to meet the sampling theorem. In particular,
Δ _P <T _s / d _max
The insertion interval should be set so that Here, T _s represents the period of the effective symbol part (symbol period after removal of the guard interval part), d _max represents the maximum value of the propagation delay of the path, and these relationships are shown in FIG. Yes. For _example, if T s = 80 [mu] s and _d max = 20 .mu.s, insertion interval delta _P should be 4 or less.

  FIG. 8 shows a portion of a transmitter according to one embodiment of the present invention. Elements already described in FIG. 2 have the same reference numbers. In FIG. 8, the dedicated pilot channel control unit 72 and the dedicated pilot channel multiplexing unit 74 are depicted in the data channel processing unit 202-1. These elements are also provided in the other data channel processing units 202-2 to 20-K. The dedicated pilot channel control unit 72 determines whether to insert the dedicated pilot channel into the signal transmitted to the mobile station according to the mobility of the mobile station. The mobility is measured, for example, at the maximum Doppler frequency, and a dedicated pilot channel may be inserted when it exceeds a predetermined value. In response to an instruction from the dedicated pilot channel control unit 72, the dedicated pilot multiplexing unit 74 inserts a dedicated pilot channel into a signal transmitted to the user or gives a signal to the common pilot multiplexing unit 204 without inserting the dedicated pilot channel.

  For example, a mobile station as shown in FIG. 3 notifies the base station of an amount by which it can be determined whether or not it is moving at high speed. Such amount is, for example, the maximum Doppler frequency, but is not limited thereto. If the dedicated pilot channel control unit 72 determines that the mobile station is moving at a high speed, the dedicated pilot channel is multiplexed with the signal by the dedicated pilot multiplexing unit. Otherwise, multiplexing of dedicated pilot channels is not performed. In this embodiment, the dedicated pilot channel is inserted in the signal to the mobile station moving at high speed, but the dedicated pilot channel is not inserted in the signal to the mobile station that is not so. In the mobile station, channel estimation accuracy can be improved by using the dedicated pilot channel for channel estimation in addition to the common pilot channel.

  FIG. 9 shows an example of the channel configuration when the frequency band is divided into a plurality of frequency blocks. Assume that one frequency block includes a large number of subcarriers. Such a frequency block is also called a chunk, a frequency chunk or a resource block. The user can use one or more chunks according to the content (data size or the like) to be communicated. In the illustrated example, frequency chunk 1 is used for a user moving at high speed, and a shared data channel and a dedicated pilot channel are multiplexed. Further, another frequency chunk 2 is used for a user who is not moving at high speed, and the dedicated pilot channel for this user is not multiplexed. Since the mobile station moving at high speed may have a large change in channel estimation value over time, the channel estimation value can be obtained with high accuracy by using both the common and dedicated pilot channels. On the other hand, in a mobile station that is stationary or moving only at a low speed, it is expected that the time change of the channel estimation value is small. If both the common and dedicated pilot channels are transmitted to such a user, the pilot channel is unnecessarily transmitted and the data transmission efficiency is deteriorated. As in the present embodiment, the dedicated pilot channel estimation unit 72 checks the mobility of the mobile station and determines whether or not the dedicated pilot channel is necessary for each user, so that the dedicated pilot channel is not transmitted unnecessarily.

  FIG. 10 shows a portion of a transmitter according to one embodiment of the present invention. Elements already described in FIG. 2 have the same reference numbers. In this embodiment, signals are transmitted using a plurality of transmission antennas. For this reason, the data channel processing unit 202-1 is provided with a dedicated pilot multiplexing unit 102, an antenna weight control unit 104, and a weight setting unit 106. Furthermore, elements such as a common pilot multiplexing unit 204, an IFFT unit 206, and a guard interval insertion unit 208 are provided in each of the plurality of transmission antennas. The dedicated pilot multiplexing unit 102 multiplexes the dedicated pilot channel to the transmitted signal. In this embodiment, dedicated pilot channels are used for all users. The antenna weight control unit 104 adjusts the weight or weight for each of the plurality of transmission antennas. By appropriately adjusting the weight, it is possible to realize a beam pattern having directivity in a specific direction or non-directional. The weight setting unit 106 sets a weight for each transmission antenna in accordance with a control signal from the antenna weight control unit 104. The weight is typically expressed by the amount of phase rotation, but in addition, the amplitude may be adjusted.

  By the way, the common pilot channel and the shared control channel need to be notified to all users, and the dedicated pilot channel only needs to be notified to a specific user. For this reason, in this embodiment, the common pilot channel and the shared control channel are transmitted by a sector beam covering all sectors. The dedicated pilot channel is transmitted by a directional beam having directivity in the direction in which the target user exists. FIG. 11 schematically shows a sector beam and a directional beam. A sector beam covering the entire sector of about 120 ° is indicated by a solid line, and a directional beam having a strong gain in the direction of a specific user is indicated by a broken line.

  FIG. 12 shows an example of the channel configuration when the frequency band is divided into a plurality of frequency blocks or chunks. The user can use one or more chunks according to the content (data size or the like) to be communicated. In the illustrated example, frequency chunk 1 is used for user 1, and another frequency chunk 2 is used for user 2. Each user can use a dedicated pilot channel specialized for the direction in which the user is located in addition to the common pilot channel that is commonly used for the entire area, so that channel estimation regarding the direction can be performed with high accuracy.

In the fourth embodiment, one directional beam is formed using a plurality of transmission antennas. On the other hand, in the MIMO (Multi Input Multi Output) multiplexing method, a plurality of transmission antennas are used independently, and separate signals are simultaneously transmitted from the respective transmission antennas at the same frequency, while the reception side has a plurality of reception antennas. The signal is received and the transmitted signal is properly separated using some signal separation algorithm. By using a plurality of transmission antennas independently, a plurality of propagation paths (channels) are formed, and the data transmission rate can be improved by several times the number of transmission antennas. Since a propagation path is formed for each antenna, it is necessary to transmit a pilot channel for each antenna and perform channel estimation for each antenna. Further, in the MIMO multiplexing method, when the number of transmission antennas N _TX and the number of reception antennas N _RX are different, it is necessary to perform communication in accordance with the smaller number of antennas. For example, even if a base station transmits signals with four transmission antennas, if the mobile station receiving them has only two reception antennas, the transmission rate expected when the four transmission antennas are fully utilized is increased. Cannot be achieved. In that case, only the throughput achievable with two transmitting antennas can be obtained. When the mobile station has only two receiving antennas, the base station transmitting signals independently from the four transmitting antennas does not contribute to improving the data transmission efficiency. From this point of view, in the fifth embodiment of the present invention, the transmission method of the base station is appropriately changed depending on the number of antennas provided in the mobile station.

  For convenience of explanation, it is assumed that the mobile station has two or four antennas, and the base station has four antennas. However, the present invention may be used for MIMO multiplexing using any suitable number of antennas. In this embodiment, the common pilot channel and the shared control channel are received by any type of mobile station, and the dedicated pilot channel is used only by the mobile station having four antennas.

  FIG. 13 illustrates a MIMO multiplexing method according to an embodiment of the present invention. As shown in the figure, a common pilot channel (and a shared control channel) is transmitted from the first and second transmission antennas of the transmitter (base station). This is used by all mobile stations. Further, dedicated pilot channels are transmitted from the third and fourth transmission antennas of the transmitter. This is only used in receivers (mobile stations) with 4 receive antennas.

  FIG. 14 shows an example of the channel configuration when the frequency band is divided into a plurality of frequency blocks or chunks. The user can use one or more chunks according to the content (data size or the like) to be communicated. In the illustrated example, frequency chunk 1 is used for user 2, and another frequency chunk 2 is used for user 1. The common pilot channel and the shared control channel are transmitted from the first and second transmission antennas in the first slot of the TTI. After the second symbol related to frequency chunk 2, a shared data channel for user 1 having only two receiving antennas is transmitted. After the second symbol related to frequency chunk 1, a dedicated pilot channel is transmitted from the third and fourth transmission antennas to user 2 having four reception antennas. Thereby, it is possible to effectively improve each user's throughput for both the user 1 and the user 2.

  FIG. 15 shows several multiplexing methods for the common pilot channel. The present invention is not limited to the illustrated example of the multiplexing method, and various multiplexing methods can be used. In Example 1, the common pilot channel is multiplexed only in the frequency direction, which corresponds to the multiplexing method shown in FIG. In Example 2, multiplexing is performed in both frequency and time directions. In Example 3, the common pilot channel is multiplexed only in the time direction.

  The downlink pilot channel can be divided into a common pilot channel and a dedicated pilot channel. The common pilot channel may be transmitted with a sector beam, or may be transmitted with multiple beams using a fixed antenna weight (fixed beam pattern) using a plurality of antennas. In the latter case, the entire sector is covered with a predetermined number of directional beams.

(Pilot channel)
The common pilot channel can be used to identify a corresponding sector of the user from a plurality of sectors belonging to the same cell. All sectors belonging to the same cell use the same scramble code (Cell-specific scramble code). The common pilot channel may be used for cell search and handover, and may be used for measurement of reference levels of neighboring cells / sectors. The common pilot channel may be used for scheduling according to instantaneous channel conditions and quality measurement for obtaining channel quality information (CQI). CQI may be used for adaptive link control, for example. The common pilot channel may be used for channel estimation of a physical channel transmitted by a sector beam or multi-beam.

  The dedicated pilot channel may be transmitted with a sector beam, may be transmitted with multiple beams, or may be transmitted with an adaptive beam (adaptive directed beam) that is adaptively generated for each user. The directional beam included in the multi-beam and the adaptive directional beam are common in that they have a strong antenna gain in a specific direction, while the former directional beam is formed with a fixed weight, while the latter adaptive The weight of the directional beam is different in that it changes depending on the position of the mobile station. That is, the former is a directional beam whose directional direction is unchanged, while the latter is a directional beam whose directional direction is variable. The dedicated pilot channel is used adaptively depending on the propagation channel conditions depending on the user or environment (may not be used). The dedicated pilot channel may be transmitted with an adaptive beam adaptively generated for each user. The dedicated pilot channel is used to assist in physical channel estimation transmitted by sector beams or multi-beams (basically, a common pilot channel is used for channel estimation). The dedicated pilot channel may be used for channel estimation of a physical channel transmitted with an adaptive beam. The dedicated pilot channel may be used for CQI measurement of a physical channel transmitted with an adaptive beam.

  FIG. 16 shows a configuration example of common and dedicated pilot channels. In the example shown, the common pilot channel is mapped to each subcarrier at a certain frequency interval within one symbol (within one time slot), and the dedicated pilot channel has a constant frequency within one or more other symbols. It is mapped to a subcarrier different from the common pilot channel at intervals. Note that the common pilot channel may be distributed and mapped to one or more symbols.

(beam)
The common pilot channel may be transmitted by a sector beam, and may be used for physical channel demodulation processing, that is, channel estimation and reception timing synchronization. Moreover, you may transmit from the transmitter of MIMO (multiple input and multiple output) system. Furthermore, channel estimation accuracy can be improved by adding a dedicated pilot channel according to the user and the environment. When a specific chunk used for the shared data channel is used only by one or few users, an additional pilot channel is added according to the propagation environment (movement speed, delay spread, received SINR, etc.) of the user. By using it, the channel estimation accuracy can be further improved. In the multicast / broadcast channel, channel estimation accuracy can be improved by additionally using a dedicated pilot channel assuming a user in the worst propagation environment in the cell. On the other hand, reference level measurement for cell search and handover, CQI measurement for scheduling, adaptive link control, and the like are performed using a common pilot channel in principle, and dedicated pilot channels may be used supplementarily.

  The common pilot channel may be used for demodulation processing of a physical channel transmitted by multiple beams, that is, for channel estimation and reception timing synchronization. Further, as in the case of the sector beam, the channel estimation accuracy can be improved by additionally using the dedicated pilot channel according to the user and the environment. On the other hand, reference level measurement for cell search and handover, CQI measurement for scheduling, adaptive link control, and the like are performed using a common pilot channel in principle, and dedicated pilot channels may be used supplementarily. When the number of multi-beams in the same cell is large, the number of pilot sequences used can be reduced by reusing the pilot sequences used to identify the beam to which the user belongs in the same cell.

  FIG. 17 shows a conceptual diagram of a pilot channel transmitted by multiple beams. In the illustrated example, five directional beams (fixed beam patterns) are used. Further, the pilot sequence is reused with two directional beams having completely different directivity directions.

  Since the adaptive (directional) beam adaptively forms a transmission beam for each user, a dedicated pilot channel is used for channel estimation. Furthermore, in order to improve channel estimation accuracy, a common pilot channel may be used for channel estimation when channel correlation in multi-beam transmission and adaptive beam transmission is high. On the other hand, CQI measurement for cell search, reference level measurement for handover, scheduling, and adaptive link control is performed using a common pilot channel transmitted in a sector beam or multi-beam in principle.

  FIG. 18 shows a pilot channel transmitted with an adaptive directed beam.

(Pilot channel configuration example)
The common pilot channel and the dedicated pilot channel may be periodically multiplexed for each TTI. Depending on the user and the environment, dedicated pilot channels are used to improve channel estimation accuracy. If a chunk is used exclusively by one or several users for a shared data channel, under special conditions such as high mobility, large delay spread, or very low SINR, a common pilot channel In addition to assigning dedicated pilot channels, accurate channel estimation is possible. Multicast / broadcast channels can improve the quality of worst-case users by using dedicated pilot channels in addition to common pilot channels. Additional user dependent dedicated pilot channel information within the shared data channel is provided by the control signaling channel. Therefore, high quality demodulation of the shared data channel is possible by using more pilot symbols with low delay. In the multicast / broad channel, additional dedicated pilot channel information depending on the environment is provided by the control signaling channel based on the user quality in the worst case environment. Using more pilot symbols with low delay provides a high quality multicast / broadcast channel.

  The pilot channel may be mapped with high density in preference to the frequency domain over the time domain. More pilot channels may be assigned to the frequency domain than to the time domain (the pilot channel density in the frequency domain may be higher than the density in the time domain). If the TTI length is relatively short, the channel fluctuation in the time domain may be slight, but the channel fluctuation in the frequency domain is expected to be larger due to the time dispersion of frequency selective multipath fading. The Therefore, it is advantageous to map the pilot channels in the frequency domain with a high density in the TDM scheme rather than dividing the pilot channels into subcarriers in the FDM scheme.

  TDM and / or FDM multiplexing may be performed by performing staggered mapping from the beginning of the TTI. As shown in FIG. 16, staggered mapping is a channel arrangement in which a channel is mapped at a certain frequency interval in a certain time slot and a channel is mapped to another frequency at a certain frequency interval in another time slot. is there. The common pilot channel and the dedicated pilot channel may be mapped using a staggered mapping scheme in each TTI. The common pilot channel may be mapped before the dedicated pilot channel with high priority. Mapping the pilot channel at the beginning of each TTI has at least the following advantages. When control signaling channels are mapped with common / dedicated pilot channels at the beginning of each TTI, control signaling channels can be reliably demodulated with accurate channel estimation under varying delay spread and channel state change due to Doppler frequency . When the control signaling channel is mapped to the head of each TTI, the UE (mobile station) performs efficient intermittent reception when no traffic data is transmitted in the chunk (that is, when only control signaling bits are transmitted). Is advantageous.

  FIG. 19 shows an example of assigning common and dedicated pilot channels in the TDM scheme.

FIG. 20A is a diagram showing a simulation result according to one embodiment of the present invention, and shows a relationship between received E _s / N ₀ and throughput. The three graphs show the values obtained when the number of time slots N _stg for pilot-stag mapping the pilot symbols is changed to 0, 1, and 2. FIG. 20B shows an example of channel mapping corresponding to each of N _stg = 0, 1, and 2. The graph plotted with white circles in FIG. 20A is related to N _stg = 0, the graph plotted with hatched circles is related to N _stg = 1, and the graph plotted with black circles is set to N _stg = 2 Related. The moving speed of the terminal is 120 km / h. According to FIG. 20A, it can be seen that as the number of time slots N _stg for mapping pilot symbols increases, the throughput characteristics improve, and staggered mapping is more effective. This is considered to be because the followability of channel estimation in the time domain is improved.

  In the mapping method of the common pilot channel and the dedicated pilot channel, the pilot symbols may be allocated discontinuously in the frequency and time domain. For example, discontinuous mapping may be performed along the frequency domain of the OFDM symbol. When pilot symbols are allocated discontinuously in the frequency and time domain, the following points are advantageous. By thinning out subcarriers for assigning pilot symbols to the frequency domain, it is possible to improve the decrease in data transmission efficiency due to the insertion of pilot symbols, and to maintain almost the same channel estimation accuracy as when no thinning is performed. The quota in the time domain decreases. For the target cell radius in an actual cellular system, the transmission power of the common pilot channel must be changed. Therefore, by thinning out pilot symbols in the frequency domain (ie, when multiple channels and pilot symbols are multiplexed in the same OFDM symbol), the transmission power of the common pilot channel can be flexibly changed while maintaining the overall transmission power. be able to.

  In the seventh embodiment of the present invention, a method of using orthogonal code sequences in sectors of the same cell site will be described. In general, a plurality of sectors are included in a cell, but the method described below can be used between sectors or between cells. In conventional W-CDMA, scrambling is performed using a different spreading code in each sector, and a pilot channel is derived by despreading the received signal with the scrambling code, and channel estimation and the like are performed. Since different scramble codes for each sector are determined at random, the pilot channel receives inter-sector interference from symbols having the same subcarrier and subframe within the sector due to inter-code (inter-code) interference. As a result, it may be relatively difficult to perform high-accuracy channel estimation and cell search, and even if it is possible, a relatively long time may be spent. This is particularly disadvantageous when fast handovers and frequent movements between multiple sectors are involved. In this regard, signal quality may be improved to some extent even in a multipath propagation environment by adopting the OFDM method for downlink data transmission of the data channel and by eliminating the need to multiply the data channel by a scramble code. unknown. However, since the pilot channel is multiplied by a different scrambling code for each sector in order to distinguish the sector, the reception quality of the pilot channel is not essentially improved, and high-accuracy channel estimation or the like is still not easy. The seventh embodiment of the present invention has been made in view of such a problem, and the problem is to improve the reception quality of the pilot channel in the downlink of the OFDM scheme.

  According to the present embodiment, a sector-specific orthogonal sequence is used for the pilot channel in addition to the cell-specific orthogonal code sequence. Thereby, the pilot channel can avoid interference from adjacent sectors of the same cell. Since inter-sector interference in the pilot channel is avoided, channel estimation accuracy is improved. Improved channel estimation accuracy is particularly advantageous for simultaneous transmissions associated with fast sector selection and soft combining.

  FIG. 21A shows the use of pilot sequences that are orthogonal between sectors (or between beams) according to this embodiment. A terminal that performs handover at the sector edge can perform channel estimation based on pilots of two base stations at the same time, and can estimate a channel at high speed and with high accuracy. For example, user # 1 located at the edge or edge of a sector (ie, a user who performs fast sector selection or soft combining) discriminates sectors by orthogonal sequence despreading and performs accurate channel estimation. realizable. User # 2, which does not perform fast sector selection or soft combining, can perform channel estimation by using the respective pilot symbols (considering cell-specific and / or sector-specific orthogonal codes). .

  FIG. 21B shows a pilot channel generator used in a transmitter according to an embodiment of the present invention. The transmitter is typically a radio base station. The pilot channel generation unit includes a pilot sequence supply unit 2102 that supplies a sequence for a pilot channel, a scramble code unit 2104 that supplies a scramble code, an orthogonal code unit 2106 that supplies a spreading code sequence (orthogonal code) that differs for each sector, A multiplier 2108 for multiplying the scramble code and the orthogonal code, and a multiplier 2110 for multiplying the output of the multiplier 2108 and the pilot sequence. The pilot sequence is a known reference sequence both between the base station and the mobile station. The scramble code is a random sequence commonly used for a plurality of sectors. The orthogonal code is set for each sector and is determined to be orthogonal to each other.

  FIG. 22 is a diagram illustrating a specific example of the orthogonal code multiplied by the pilot sequence. As shown in the figure, in sector # 1, codes such as (1, 1, 1, 1, 1, 1, 1, 1,...) Are mapped at one subcarrier interval. In sector # 2, codes such as (1, -1,1, -1,1, -1,1, -1, ...) are mapped at one subcarrier interval. In sector # 3, codes such as (1, -1, -1,1,1, -1, -1,1,...) Are mapped at one subcarrier interval. These codes are orthogonal to each other.

FIG. 23 is a diagram showing another specific example of the orthogonal code multiplied by the pilot sequence. Although it is the same as that of FIG. 22, the orthogonalization of a code | symbol is implement | achieved by rotating a phase. In sector # 1, codes such as (1, 1, 1, 1, 1, 1, 1, 1,...) Are mapped at one subcarrier interval. Sector # In ^{2 (1, e j2 / 3π} , e -j2 / 3π, 1, e j2 / 3π, e -j2 / 3π, 1, e j2 / 3π, ...) code one subcarrier as Mapped by interval. In sector # 3, a code such as (1, e ^{−j2 / 3π} , e ^{j2 / 3π} , 1, e ^{−j2 / 3π} , e ^{j2 / 3π} , 1, e ^{−j2 / 3π} ,...) It is mapped by carrier interval. Even such codes can be orthogonal to each other.

  FIG. 24 is a diagram illustrating an example of a correspondence relationship between a scramble code and an orthogonal code. In the example shown in the figure, 40 subcarriers are assumed in the usable channel band, and various data are associated with these subcarriers to perform OFDM data transmission. Of course, the numerical values shown are merely examples. The channel band may be the entire band available in the system or may represent one chunk. In the illustrated example, the scramble code is represented by 40 data sequences, which are mapped to 40 subcarriers, respectively. In the figure, numerals 1 to 40 relating to the scramble code represent individual codes constituting the scramble code. The scramble codes in the first and second lines are shifted by one from each other because the scramble codes used at the first and second lines are equal to each other, but the correspondence in the frequency axis direction is shifted by one. Indicates that it will be sent. Thereby, homogenization of the signal in the frequency axis direction can be achieved.

In the example described with reference to FIG. 22 above, in sector # 1, this scramble code is multiplied by an orthogonal code such as (1, 1, 1, 1,...), Which is multiplied by the pilot sequence. In sector # 2, the scramble code is multiplied by an orthogonal code such as (1, -1, -1,1,...), Which is multiplied by the pilot sequence. In sector # 3, the scramble code is multiplied by an orthogonal code such as (1,1, -1, -1, ...), and this is multiplied by the pilot sequence. In the example described in FIG. 23, in the sector # 1, this scramble code is multiplied by an orthogonal code such as (1, 1, 1, 1,...), Which is multiplied by the pilot sequence. In sector # 2, the scramble code is multiplied by an orthogonal code such as (1, e ^{j2 / 3π} , e ^{−j2 / 3π} ,...), And this is multiplied by the pilot sequence. In sector # 3, the scramble code is multiplied by an orthogonal code such as (1, e ^{−j2 / 3π} , e ^{j2 / 3π} ,...), And this is multiplied by the pilot sequence.

  FIG. 25 shows an example in which a common pilot channel and other channels are multiplied by a scramble code and an orthogonal code. In FIG. 25, a supply unit 2502 that supplies a sequence for a common pilot channel, a supply unit 2504 that supplies a data sequence for another channel, a scramble code unit 2506 that supplies a scramble code, and a spreading that differs for each sector. An orthogonal code unit 2508 that supplies a code sequence (orthogonal code), a multiplier unit 2510 that multiplies the scramble code and the orthogonal code, a multiplier unit 2512 that multiplies the data sequence for the multiplication 2510 and other channels, and a multiplier unit 2510 A multiplier 2514 for multiplying the output and the pilot sequence. As described above, the scramble code is set in common to a plurality of sectors, and the orthogonal code is set to be different (orthogonal) for each cell. In the illustrated example, the common pilot channel and other channels are multiplied by the same scramble code and the same orthogonal code.

  FIG. 26 shows another example of multiplying the common pilot channel and other channels by a scramble code and an orthogonal code. Elements already described in FIG. 25 are denoted by the same reference numerals, and redundant description is omitted. In FIG. 26, a second scramble code unit 2602 and a multiplier unit 2604 that multiplies the second scramble code and the orthogonal code are depicted. The first scramble code unit 2506 outputs a first scramble code common to a plurality of sectors. A second scramble code is output from the scramble code unit 2602 according to a predetermined rule from the first scramble code, and is input to the multiplier unit 2604. The output of the multiplier 2604 is multiplied with the data sequence of channels other than the common pilot channel. Accordingly, the common pilot channel is multiplied by the first scramble code and the orthogonal code, while the other channels are multiplied by the second scramble code and the orthogonal code. As a result, the common pilot channel and other channels can be distinguished by the spreading code. In this embodiment, since the second scramble code is derived from the first scramble code, the receiver can easily search for any channel as long as the derivation rule is known.

  FIG. 27 shows a state where the examples shown in FIGS. 25 and 26 are combined. The present embodiment is not limited to the illustrated example, and may be applied to various channel combinations. The combination as shown in the figure is advantageous in that, for example, a shared data channel whose spreading factor may vary and a channel whose spreading factor is kept constant can be easily distinguished.

  In addition to suppressing interference related to the pilot channel as described above, the transmission power of the shared data channel may be adjusted.

  28A, 28B, and 28C show signals received by a certain user. FIG. 28A shows a signal (desired signal) received from a cell or sector to which a certain user is connected. In the figure, the pilot channel is drawn larger than the data channel, indicating that the pilot channel is transmitted and received with higher power than the data channel. FIG. 28B shows a signal (undesired signal) that is not a desired signal for a certain user. The undesired signal indicates a signal from a cell other than the cell to which the user is connected, or a signal from a sector other than the connected sector, and becomes an interference signal for the desired signal. In the above embodiment, different orthogonal codes are used for the pilot channels of the desired signal and the undesired signal, respectively, and interference related to the pilot channel is suppressed. In FIG. 28C, the downlink transmission timing or frequency band is adjusted between base stations or between sectors, and the base station transmits a data channel so that interference between a desired signal and an undesired signal is reduced. It is shown that power (transmission power of undesired signals) is suppressed to a small level or transmission is stopped. More generally, the transmission power of undesired signals is limited to less than a predetermined value. As a result, interference between data channels that may be a concern in FIG. 28B can be suppressed. Alternatively, instead of reducing the transmission power of undesired signals (including zero), the user may perform soft combining by simultaneously transmitting the same data channel from different cells.

  In the eighth embodiment of the present invention, orthogonal pilot mapping for MIMO transmission is described. Orthogonal multiple pilot channels may be used for antenna gain techniques such as MIMO multiplexing, MIMO diversity, and adaptive array antenna transmission. As an example, the common pilot channel is transmitted by MIMO transmission from all antennas of the transmitter. This is because a pilot channel is required for CQI measurement for all signal transmissions. All the overhead of common pilot symbols is the same regardless of the number of transmit antennas. This is to ensure the corresponding cell coverage area for the data channel by using MIMO transmission. In MIMO transmission, channel estimation is further improved by using dedicated pilot channels (the number of common pilot symbols per antenna in a 4-branch MIMO transmission is 1/4 that of a single antenna transmission). (3) Adaptive partial pilot symbol mapping for MIMO transmission, i.e., pilot symbols from the sector beam transmission type transmission mode may be thinned out in frequency and time domain according to application scenarios such as delay spread and moving speed. Good.

  FIG. 29 shows an orthogonal sequence between sectors for a pilot channel for MIMO. This shows the case of a 4-antenna transmitter. The dedicated pilot channel is used to supplement channel estimation. In the figure, # 1, # 2, # 3, and # 4 indicate that they correspond to the first, second, third, and fourth transmission antennas, respectively.

  In the seventh and eighth embodiments, the inter-cell interference or inter-sector interference related to the pilot channel is suppressed by multiplying the pilot channel by the orthogonal code. From the viewpoint of increasing the interference suppression effect, it is preferable to use such an orthogonal code, but from the viewpoint of distinguishing cells and / or sectors, it is not essential that the orthogonal code is used, and non-orthogonal is used. A code may be used. However, when a non-orthogonal code represented by a general random sequence is used, there is a concern that the quality of the pilot channel may deteriorate due to intersymbol interference as mentioned at the beginning of the seventh embodiment. On the other hand, some non-orthogonal codes have less intersymbol interference (correlation) than random sequences depending on the type. Cells and / or sectors may be distinguished using such a highly correlated code (for example, a code in which intersymbol interference is on average about 1 / code length). An example of a code having such a property is a CAZAC code. The outline of the Kazak code will be described below.

  As shown in FIG. 30, it is assumed that the code length of a certain Kazak code A is L. For convenience of explanation, it is assumed that this code length corresponds to a period of L samples, but such an assumption is not essential to the present invention. A series of Δ samples (indicated by hatching in the figure) including the last sample (L-th sample) of the Kazak code A is shown at the lower side of FIG. As shown, another code B is generated. In this case, Kazak codes A and B have a relationship orthogonal to each other with respect to Δ = 1 to (L−1). That is, a certain Kazak code and a code obtained by cyclically shifting the Kazak code are orthogonal to each other. Therefore, when one Kazak code with a code length L is prepared, theoretically L code groups orthogonal to each other can be prepared. Further, a certain Kazak code A and another Kazak code B that is not derived from the cyclic shift of the Kazak code A are non-orthogonal to each other, but their intersymbol interference amount is more than the interference amount between different random sequences. Few. Further, the amount of intersymbol interference between a code sequence composed of a part of a certain Kazak code A and a code sequence composed of another part of the Kazak code A or B is also smaller than the amount of interference between different random sequences. Details on Kazak codes are described in, for example, the following document: DCChu, “Polyphase codes with good periodic correlation properties”, IEEE Trans. Inform. Theory, vol. IT-18, pp. 531-532, July. 1972; 3GPP, R1-050822, Texas Instruments, “On allocation of uplink sub-channels in EUTRA SC-FDMA”.

  In the seventh embodiment, the eighth embodiment, and the ninth embodiment, the pilot channels of the desired signal and the undesired signal are transmitted simultaneously. In the tenth embodiment of the present invention, as shown in FIG. 31, the pilot channels of the desired signal and the undesired signal are transmitted from the base station so that both time and / or frequency are different. This effectively suppresses inter-cell and / or inter-sector interference related to the pilot channel. Further, as shown on the desired signal side in FIG. 31, if the transmission of the data channel of the desired signal is prohibited during the time when the pilot channel of the undesired signal is transmitted, the interval between the desired signal and the undesired signal is reduced. Interference can be further suppressed.

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

(Section 1)
A multiplexing means for multiplexing the common pilot channel, the shared control channel, and the shared data channel;
Means for performing inverse Fourier transform on the multiplexed signal to generate a symbol;
Means for transmitting the generated symbols;
The multiplexing means includes a shared control channel including control information necessary for demodulation of a shared data channel including a payload, and a common pilot channel commonly used by a plurality of users in the frequency direction, A transmitter characterized by multiplexing in the time direction or a combination thereof, and multiplexing the common pilot channel, the shared control channel, and the shared data channel in the frequency direction, the time direction, or a combination thereof.

(Section 2)
The multiplexing means multiplexes a dedicated pilot channel used for demodulation of a shared data channel and used for one or more specific users, a common pilot channel and a shared control channel in the frequency direction, the time direction, or a combination thereof. The transmitting apparatus according to claim 1, wherein:

(Section 3)
The transmitting apparatus according to claim 2, wherein the dedicated pilot channel is time-multiplexed at a first frequency at a constant frequency interval and time-multiplexed at a constant frequency interval at a second time.

(Section 4)
The transmitting apparatus according to claim 2, wherein the dedicated pilot channel is transmitted to a communication partner that moves at high speed, but is not transmitted to a communication partner that does not move at high speed.

(Section 5)
Having means for adjusting the directivity of the transmission beam to a specific communication partner;
The transmission apparatus according to claim 2, wherein the dedicated pilot channel is inserted for each specific communication partner.

(Section 6)
Having multiple transmit antennas,
A common pilot channel is transmitted from one or more transmit antennas;
The transmission apparatus according to claim 2, wherein the dedicated pilot channel is transmitted from one or more other transmission antennas.

(Section 7)
The transmission apparatus according to claim 2, wherein the common pilot channel and the dedicated pilot channel are discontinuously mapped in the time direction, in the frequency direction, or in both the time and frequency directions.

(Section 8)
The transmission apparatus according to claim 1, wherein the common pilot channel is transmitted together with codes orthogonal to each other between cells or sectors.

(Section 9)
The transmitting apparatus according to claim 1, wherein all or part of a Kazak code having a predetermined code length constitutes the common pilot channel.

(Section 10)
10. The transmission power of a shared data channel of a different cell or sector is suppressed to a value less than a predetermined value when a shared data channel of a certain cell or sector is transmitted. Transmitter.

(Section 11)
The transmission of the common pilot channel is performed such that the time and / or frequency of transmitting the common pilot channel of a certain cell or sector and the common pilot channel of a different cell or sector are different. The transmission device according to item 9.

(Section 12)
The transmission apparatus according to claim 11, wherein when a common pilot channel of a certain cell or sector is transmitted, the transmission power of the shared data channel of another cell or sector is suppressed to be less than a predetermined value.

(Section 13)
A shared control channel including control information necessary for demodulation of a shared data channel including a payload and a common pilot channel commonly used by a plurality of users are multiplexed in the frequency direction, the time direction, or a combination thereof, and the common pilot channel and A shared control channel and a shared data channel are multiplexed in the frequency direction, the time direction, or a combination thereof;
Inverse Fourier transform the multiplexed signal to generate symbols,
A transmission method characterized by transmitting a generated symbol.

(Section 14)
Means for receiving a symbol transmitted from a transmission device;
Means for Fourier transforming the received symbols;
Separating means for separating the common pilot channel, the shared control channel and the shared data channel from the signal after Fourier transform;
A receiving device comprising:
The separation means separates a common pilot channel commonly used by a plurality of users and a shared control channel including control information necessary for demodulation of the shared data channel by frequency, time, or a combination thereof, A receiving apparatus, wherein a shared control channel and a shared data channel including a payload are separated by frequency, time, or a combination thereof.

(Section 15)
Receives the symbol transmitted from the transmitter,
Fourier transform the received symbol,
A shared control channel including control information necessary for demodulation of a shared data channel including a payload and a common pilot channel commonly used by a plurality of users are separated by frequency, time, or a combination thereof, and the common pilot channel and the shared control are separated. A receiving method characterized in that a channel and a shared data channel are separated by frequency, time, or a combination thereof.

(Section 16)
Means for generating a common pilot channel commonly used by a plurality of mobile stations;
Multiplexing means for multiplexing two or more channels to be transmitted;
Means for performing inverse Fourier transform on the multiplexed signal to generate a symbol for wireless transmission;
First multiplication means for multiplying a common pilot channel by a spread code sequence common to a plurality of sectors and a different orthogonal code sequence for each sector;
A transmission device comprising:

(Section 17)
17. The transmission apparatus according to claim 16, wherein the first multiplying unit multiplies a channel other than the common pilot channel by a spreading code sequence common to a plurality of sectors and an orthogonal code sequence different for each sector. .

(Section 18)
Deriving means for deriving another spreading code sequence from a spreading code sequence common to a plurality of sectors according to a predetermined rule;
Second multiplying means for multiplying a channel other than the pilot channel by the derived spreading code sequence;
18. The transmitter according to claim 17, further comprising:

(Section 19)
The first multiplication means multiplies a common pilot channel and a shared control channel by a spreading code sequence common to a plurality of sectors and a different orthogonal code sequence for each sector,
The transmitting apparatus according to claim 18, wherein the second multiplying unit multiplies the shared data channel by the other spreading code sequence.

202-1 to K Data channel processing unit 210 Spreading and channel coding unit 212 Interleaving processing unit 214 Data modulation unit 216 Time / frequency mapping unit 204 Common pilot multiplexing unit 206 IFFT unit 208 Guard interval insertion unit 302 Guard interval removal unit 304 FFT Unit 306 common pilot separation unit 308 channel estimation unit 310 individual pilot separation unit 312 time / frequency data extraction unit 314 data demodulation unit 316 deinterleave processing unit 318 despreading and channel decoding unit 72 individual pilot channel control unit 74 individual pilot multiplexing unit 102 Dedicated pilot multiplexing unit 104 Antenna weight control unit 106 Weight setting unit 2102 Pilot sequence supply unit 2104 Scramble code unit 2106 Orthogonal Code unit 2108, 2110 Multiply unit 2502, 2504 Supply unit 2506 Scramble code unit 2508 Orthogonal code unit 2510, 2512, 2514 Multiply unit 2602 Scramble code unit 2604 Multiply unit

Claims (14)

A multiplexing means for multiplexing the common pilot channel, the shared control channel, and the shared data channel;
Means for performing inverse Fourier transform on the multiplexed signal to generate a symbol;
Means for transmitting the generated symbols;
A transmission apparatus having the multiplexing means, the common pilot for use in common to the shared control channel and a plurality of users including control information necessary for demodulation of the shared data channel including (1) Payload channel and the frequency direction, and multiplexed by the time direction, or a combination thereof, (2) with respect to said common pilot channels and the shared control channels, more multiplexes the shared data channel in time direction, (3) the The dedicated pilot channel used for demodulating the shared data channel and the shared data channel assigned to a specific user are multiplexed in the frequency direction, the time direction, or a combination thereof, and (4) the frequency band is divided The common pilot channel is arranged in each of a plurality of resource blocks, and a part Transmission and wherein the placement of the dedicated pilot channel in the resource block. The dedicated pilot channel is time-multiplexed at a constant frequency interval at a first time and is also time-multiplexed at a constant frequency interval at a second time.
The transmission apparatus according to claim 1. The dedicated pilot channel is transmitted to a communication partner that moves at high speed, but is not transmitted to a communication partner that does not move at high speed.
The transmission apparatus according to claim 1. Having means for adjusting the directivity of the transmission beam to a specific communication partner;
The dedicated pilot channel is inserted for each specific communication partner
The transmission apparatus according to claim 1. Having multiple transmit antennas,
The common pilot channel is transmitted from one or more transmit antennas;
The dedicated pilot channel is transmitted from another one or more transmission antennas
The transmission apparatus according to claim 1. The common pilot channel and the dedicated pilot channel are mapped discontinuously in the time direction, in the frequency direction, or in both the time and frequency directions
The transmission apparatus according to claim 1. The common pilot channel is transmitted with codes orthogonal between cells or sectors
The transmission apparatus according to claim 1. All or part of a Kazak code having a predetermined code length constitutes the common pilot channel
The transmission apparatus according to claim 1. When the shared data channel of a certain cell or sector is transmitted, the transmission power of the shared data channel of a different cell or sector is suppressed below a predetermined value
The transmission apparatus according to claim 7 or 8, wherein The transmission of the common pilot channel is performed so that the time and / or frequency of transmitting the common pilot channel of a cell or sector and the common pilot channel of a different cell or sector are different.
The transmission apparatus according to claim 7 or 8, wherein When the common pilot channel of one cell or sector is transmitted, the transmission power of the shared data channel of another cell or sector is suppressed below a predetermined value.
The transmitter according to claim 10. (1) A shared control channel including control information necessary for demodulation of a shared data channel including a payroat and a common pilot channel commonly used by a plurality of users are multiplexed in the frequency direction, the time direction, or a combination thereof. 2) The shared data channel is multiplexed in the time direction with respect to the common pilot channel and the shared control channel, and (3) an individual pilot channel used for demodulation of the shared data channel and assigned to a specific user The shared data channel is multiplexed in the frequency direction, the time direction, or a combination thereof, and (4) the common pilot channel is arranged in each of a plurality of resource blocks that divide the frequency band, and some resources Placing the dedicated pilot channel in a block;
Inverse Fourier transform the multiplexed signal to generate symbols,
Send generated symbols
A transmission method characterized by the above. Means for receiving a symbol transmitted from a transmission device;
Means for Fourier transforming the received symbols;
Separating means for separating the common pilot channel, the shared control channel and the shared data channel from the signal after Fourier transform;
A receiving device comprising:
The separation means (1) separates the common pilot channel used in common by a plurality of users and the shared control channel including control information necessary for demodulation of the shared data channel by frequency, time, or a combination thereof. (2) separating the shared data channel including a payload from the common pilot channel and the shared control channel according to time, and (3) a dedicated pilot channel used for demodulating the shared data channel; Separating the shared data channel assigned to a specific user by frequency direction, time direction, or a combination thereof; and (4) extracting the common pilot channel from each of a plurality of resource blocks that divide the frequency band; The dedicated pilot channel from some resource blocks To extract
A receiving apparatus. Receives the symbol transmitted from the transmitter,
Fourier transform the received symbol,
(1) A shared control channel including control information necessary for demodulation of a shared data channel including a payload and a common pilot channel used in common by a plurality of users are separated by frequency, time, or a combination thereof; (2) The shared data channel is separated by time from the common pilot channel and the shared control channel, and (3) the dedicated pilot channel used for demodulation of the shared data channel and the specific user assigned to a specific user The shared data channel is separated by the frequency direction, the time direction, or a combination thereof, and (4) the common pilot channel is extracted from each of a plurality of resource blocks that divide the frequency band, and the individual data channel is extracted from some resource blocks Extract pilot channel
And a receiving method.

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