WO2008047722A1

WO2008047722A1 - Mobile communication system, control device, base station device control method, and program

Info

Publication number: WO2008047722A1
Application number: PCT/JP2007/069986
Authority: WO
Inventors: Yasuhiro Hamaguchi; Hideo Namba; Shimpei To; Kimihiko Imamura; Yasuyuki Kato; Daiichiro Nakashima
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-10-13
Filing date: 2007-10-12
Publication date: 2008-04-24

Abstract

A mobile communication system includes a plurality of base station devices including radio transmission means for radio-transmitting communication data to a mobile station device. The system includes: transmission control means for radio-transmitting communication data at a predetermined timing from each of the base station devices; and delay amount decision means for deciding a delay amount for each of the base station devices in such a manner that the delay amounts are different between the base station devices. When radio-transmitting communication data by the radio transmission means in accordance with control by the transmission control means, each of the base station devices delays the radio-transmission of the communication data from a predetermined timing in accordance with the delay amount decided by the delay amount decision means.

Description

Specification

Mobile communication system, control apparatus, base station apparatus control method, and program

TECHNICAL FIELD [0001] The present invention relates to a mobile communication system, a control apparatus, a base station apparatus control method, and a program, and more particularly to a mobile communication system, a control apparatus, a base station apparatus control method, and a program that perform delay diversity.

This application (October 2006, No. 13-2006, Japanese patent application No. 2006- 280128, filed here, claims priority, and the contents thereof are incorporated herein by reference.

Background art

In recent mobile communication systems, telephone service and Internet connection service are provided due to the relationship between one base station device and one mobile station device. In such information distribution by one-to-one communication between the base station device and the mobile station device, radio resources are secured for each mobile station device.

[0003] On the other hand, in recent years, there has been an increasing interest in broadcast multimedia services that simultaneously deliver multimedia information such as sports broadcasts, weather forecasts, and radio programs to a plurality of users. In the broadcast multimedia service, the base station device transmits data to a plurality of mobile station devices using a common wireless resource. As a result, more efficient use of radio resources is realized compared to the above-described information distribution by one-to-one communication.

[0004] The 3GPP (3rd Generation Partnership Project) calls such a technology that enables broadcast-type multimedia services as ΜΒΜ≥> (ιιιimedia Broadcast Multicast Service). In this MBMS, a form in which the above-mentioned distribution is performed in units of base station apparatuses (hereinafter referred to as single cell MBMS) and a form in which a plurality of base station apparatuses distribute the same data (hereinafter referred to as multi-cell MBMS). There is.

[0005] It should be noted that a base station apparatus is usually composed of a plurality of sector apparatuses, and in a single cell MBMS, the same data is distributed from each sector apparatus. Since each sector device functions as an independent base station device, hereinafter, unless otherwise specified, the term “base station device” refers to a sector device. [0006] In MBMS, soft compiling, which is one of the techniques for improving the reception characteristics of a mobile station apparatus, is particularly used where the received power is small, such as a cell edge. When using soft combining, the mobile station apparatus receives and combines the data transmitted by each of the base station apparatuses. As a result, the reception power is increased and the reception characteristics are improved as compared with the case where only the data transmitted by a single base station apparatus is received.

Meanwhile, delay diversity is known as another technique for improving the reception characteristics of a mobile station apparatus. Delay diversity is a technique for improving reception characteristics by separating and extracting delay components caused by reflection and the like in a mobile station apparatus and treating the same data as if it were received multiple times.

However, in order to separate and extract the delay component, the delay amount needs to be larger than a certain level. Therefore, there is a technique for ensuring that a delay amount equal to or greater than a predetermined value is obtained by intentionally transmitting a delay component in the base station apparatus. As a specific example of this technique, there is a CDTD (Cyclic Delay Transmit Diversity) technique described in Patent Document 1. The CDTD technique is a technique proposed in an Orthogonal Frequency Division Multiplexing (OFDM) (Orthogonal Frequency Division Multiplexing Access) system. This CDTD technique will be described in detail below.

[0009] The CDTD technology is provided with a plurality of antennas in a base station apparatus, and delay effects of different delay amounts are given to the respective antennas so that a mobile station apparatus can obtain the effect of delay diversity. This effect increases as the number of antennas increases.

FIG. 16 is a diagram illustrating an example of functional blocks of the base station apparatus 200 that employs OFDMA and CDTD techniques. As shown in the figure, the base station device 200 includes a data scheduling unit 210, a channel estimation code selection unit 220, a mapping unit 230, an S / P (serial / parallel) conversion unit 240, an interleaving unit 250, 2 One transmission unit 260 is included. Each transmission unit 260 includes a plurality of phase rotation units 261, an IFFT dnverseFast Fourier Transform (inverse fast Fourier transform) unit 262, a P / S (Parallel / serial: Parallel IJ) conversion unit 263, a GI (Guard Interval: Guard innovator) Addition part 264, D / A (Digital / Analog: digital / analog) conversion part 265, RF (Radio Frequency: wireless) part 266, antenna 267 Consists of including.

Data scheduling section 210 performs transmission data scheduling and the like, and outputs the result to mapping section 230. Propagation path estimation code selection section 220 selects a propagation path estimation signal used for estimating propagation path characteristics in the mobile station apparatus, and outputs it to mapping section 230. Mapping section 230 generates a data symbol sequence composed of a plurality of data symbols obtained by modulating different subcarriers based on the input transmission data and propagation path estimation signal, and S / P conversion section 240 To enter. S / P conversion section 240 performs serial-parallel conversion on each data symbol constituting the data symbol sequence, and outputs parallel to phase rotation section 261 for each subchannel composed of a plurality of subcarriers. To do.

Note that the S / P converter 240 outputs the same signal to each transmitter 260.

[0012] Interleaving section 250 performs predetermined replacement of the order of data symbols output in parallel by S / P conversion section 240 to each phase rotation section 261 before being input to each phase rotation section 261. Replace according to the rules!

Each phase rotation unit 261 receives input of CDTD transmission information indicating whether or not the input data symbol string is a target of cyclic delay transmission from a control unit (not shown). Then, when it is an object of cyclic delay transmission, a predetermined phase rotation is given to each input data symbol and output to IFFT section 260. Note that the amount of phase rotation given here differs depending on the transmitter 260. Also, the phase rotation units 261 may differ from each other.

The IFFT unit 262 obtains a plurality of sample values (samples) by performing inverse fast Fourier transform processing on the input data symbol sequence, and outputs the sample values to the P / S conversion unit 263 in parallel. The set of samples obtained in this way is called an OFDM symbol. P / S conversion section 263 performs parallel / serial conversion on the OFDM symbols input in parallel, and serially outputs them to GI addition section 264.

[0015] The calorie unit with GI 264 adds a GI to the input OFDM symbol and outputs it to the D / A conversion unit 265. All the processing so far is performed by digital processing, and the amplitude of the OFDM symbol input to the D / A conversion unit 265 is indicated by a digital value. D / A conversion The unit 265 acquires an analog signal based on the digital value and outputs the analog signal to the RF unit 266. The RF unit 266 converts the frequency of the input analog signal into a transmission band frequency, and transmits it from the antenna 267 to the radio section.

[0016] As described above, in the CDTD technique, the base station apparatus 200 gives different phase rotations for each transmission unit 260. When such phase rotation is given, the mobile station apparatus responds to the amount of rotation. Since the same effect as the amount of delay is obtained, the delay diversity effect can be obtained in the mobile station apparatus.

Patent Document 1: Japanese Patent Laid-Open No. 2005-354708

Disclosure of the invention

Problems to be solved by the invention

[0017] However, although the CDTD technique can cause different delays for each transmission unit (antenna) in a single base station apparatus, the mobile station apparatus can have a plurality of base stations as in the MBMS. When receiving data transmitted from each station device, there is a problem that the effect of delay diversity cannot be obtained between the data transmitted by each base station device.

[0018] Accordingly, one of the problems of the present invention is that when the mobile station apparatus receives data transmitted from a plurality of base station apparatuses, the data transmitted by each base station apparatus respectively. The present invention provides a mobile communication system, a control device, a base station device control method, and a program capable of realizing delay diversity between devices.

Means for solving the problem

[0019] A mobile communication system which is effective in the present invention for solving the above-mentioned problems is a mobile communication system including a plurality of base station apparatuses each including a wireless transmission means for wirelessly transmitting communication data to a mobile station apparatus. The transmission control means for wirelessly transmitting the communication data at a predetermined timing from each of the plurality of base station apparatuses, and the delay amount for each base station apparatus so as to be different for each base station apparatus. A delay amount determining means for determining, wherein each of the base station devices is determined by the delay amount determining means when wirelessly transmitting the communication data by the wireless transmitting means in accordance with control of the transmission control means. The wireless transmission of the communication data is delayed from the predetermined timing according to the delay amount. It is a sign.

[0020] According to this, since the communication data is transmitted after the delay amount determined to be different for each base station apparatus, the mobile station apparatus uses the data transmitted from each base station apparatus. When receiving, delay diversity between the data transmitted by each base station apparatus is realized.

[0021] In addition, in the mobile communication system, the wireless transmission means performs inverse discrete Fourier transform processing on a data symbol sequence composed of a plurality of data symbols each obtained by modulating the communication data. Each of the base station devices according to control of the transmission control means, and a radio transmission unit that wirelessly transmits a sample sequence obtained as a result of the inverse discrete Fourier transform process. When the communication data is wirelessly transmitted by the wireless transmission unit, the sample sequence obtained as a result of the inverse discrete Fourier transform process is cyclically delayed in accordance with the delay amount determined by the delay amount determination unit. The wireless transmission of data may be delayed from the predetermined timing.

[0022] According to this, delay diversity between data transmitted by each base station apparatus is realized by cyclically delaying the sample string.

[0023] In addition, in the mobile communication system, the wireless transmission means performs inverse discrete Fourier transform processing on a data symbol sequence composed of a plurality of data symbols each obtained by modulating the communication data. Each of the base station devices according to control of the transmission control means, and a radio transmission unit that wirelessly transmits a sample sequence obtained as a result of the inverse discrete Fourier transform process. When wirelessly transmitting the communication data by the wireless transmission means, by rotating the phase of each of the plurality of data symbols constituting the data symbol sequence according to the delay amount determined by the delay amount determination means, The wireless transmission of the communication data may be delayed from the predetermined timing.

[0024] According to this, by rotating the phase of each data symbol, delay diversity between data transmitted by each base station apparatus is realized.

[0025] Also, in each of the mobile communication systems described above, the wireless transmission means includes a data symbol sequence composed of a plurality of data symbols obtained by modulating the communication data. An inverse discrete Fourier transform unit that performs an inverse discrete Fourier transform process on the radio signal, and a radio transmission unit that wirelessly transmits a sample sequence obtained as a result of the inverse discrete Fourier transform process, wherein each of the base station devices transmits the transmission When the communication data is wirelessly transmitted by the wireless transmission means in accordance with control of the control means, a plurality of data symbol sequences that are grouped according to the delay amount determined by the delay amount determination means By rotating the phase of each data symbol for each loop, wireless transmission of the communication data may be delayed from the predetermined timing.

[0026] According to this, the amount of phase rotation can be unified within a group.

[0027] Further, in the mobile communication system, each base station apparatus has a rotation amount corresponding to the delay amount determined by the delay amount determination means and the position of each data symbol in the data symbol sequence. The phase rotation may be given to each data symbol.

[0028] According to this, the force S is used to vary the amount of phase rotation for each data symbol (each subcarrier).

[0029] In addition, in each of the mobile communication systems described above, the wireless transmission means sets the position of each data symbol in the data symbol sequence to the delay amount determined by the delay amount determination means. It is good also as including the interleaving part which replaces according to the permutation rule according to and inputs into the said inverse discrete Fourier-transform part.

[0030] It is known that when cyclic delay transmission is performed, a trough in received power occurs with a frequency width corresponding to the delay amount. For this reason, when a data symbol is transmitted to a certain user using a plurality of subcarriers, if the frequency width between the plurality of subcarriers is exactly the same as the above frequency width, the user is notified. All data symbols transmitted in this way are received with their received power lowered, which is undesirable. According to the above configuration, it is possible to prevent the frequency width between subcarriers used for data symbol transmission for a certain user from being coincident with the frequency width in which the valley of the received power is generated.

[0031] Further, in each of the above mobile communication systems, the mobile communication system includes a control device for controlling each of the base station devices, and the delay amount determining means is provided in the control device. The control device is configured to determine the delay amount determined by the delay amount determination means. Transmission means for transmitting to the respective base station apparatuses, each base station apparatus transmits the communication data by the wireless transmission means under the control of the transmission control means. When wirelessly transmitting, the wireless transmission of the communication data may be delayed from the predetermined timing in accordance with the delay amount information received from the control device.

[0032] According to this, since the control device (exchanger or the like) collectively determines the delay amount for each base station device, the delay amounts of the respective base station devices can be surely made different from each other.

[0033] Further, in this mobile communication system, the delay amount determining means may determine the delay amount based on a random value.

[0034] According to this, the control device can determine the delay amount based on the random value.

[0035] Also, in each of the above mobile communication systems, the delay amount determining means is provided in each of the plurality of base station apparatuses, and determines the delay amount based on a random value. Yes, that's good.

[0036] According to this, since the delay amount is determined based on the random value, even if each base station device determines the delay amount, the base station device Make sure that the delays are different from each other.

[0037] Further, in this mobile communication system, the delay amount determination means is provided in each of the plurality of base station apparatuses, and is a random value determined for each cell and a value set in advance for each sector. The delay amount may be determined based on the above.

[0038] According to this, since the delay amount is determined using a random value determined for each cell and a value preset for each sector, a delay amount difference between sectors that is relatively easy to predict. It is possible to ensure the delay amount difference between cells that is relatively difficult to predict while ensuring the above.

[0039] In addition, in the mobile communication system, the wireless transmission means includes one known data symbol obtained by modulating known data and the communication data according to the phase of the known data symbol. One or a plurality of data symbols obtained by modulating the signal may be transmitted wirelessly.

[0040] The mobile station apparatus receives data symbol sequences respectively transmitted from a plurality of base station apparatuses. When the content is different for each base station device, in general, the mobile station device can receive only the data symbol sequence transmitted by V, whichever base station device is V / !, but the data symbol sequence Can be received if it only receives a constant phase rotation as a whole. According to the mobile communication system, even if the phase of the known data symbol is different between base station apparatuses, in general, the mobile station apparatus can receive only the data symbol 歹 IJ transmitted by one of the base station apparatuses. However, by modulating the phase of the data symbol transmitted subsequent to the known data symbol according to the phase of the known data symbol, the data symbol string as a whole undergoes a constant phase rotation. Therefore, the mobile station apparatus can receive the data symbol sequence transmitted by each base station apparatus because it can create the same state as in the case where it is not. As a result, when the mobile station apparatus receives data transmitted from a plurality of base station apparatuses, it is possible to use different known data among the base station apparatuses.

[0041] In addition, in the mobile communication system, the wireless transmission means modulates the known data unified between the base station devices, and the communication data. It is also possible to wirelessly transmit one or a plurality of data symbols obtained by modulating the received data.

[0042] According to this, since the known data is unified among the base station apparatuses! /, The mobile station apparatus can receive the data symbol sequence transmitted by each base station apparatus.

[0043] Further, the control device according to the present invention is a control device for controlling a plurality of base station devices each including a wireless transmission means for wirelessly transmitting communication data, and each of the plurality of base station devices. From the transmission control means for wirelessly transmitting the communication data at a predetermined timing, the delay amount determining means for determining the delay amount for each base station apparatus so as to be different for each base station apparatus, and the delay amount determination Transmission means for transmitting delay amount information indicating the delay amount determined by the means to each of the base station devices.

[0044] Further, the base station apparatus control method according to the present invention is a base station apparatus control method for controlling a plurality of base station apparatuses each including a wireless transmission means for wirelessly transmitting communication data. The communication data is transmitted from each of the base station devices at a predetermined timing. A transmission control step for wirelessly transmitting data, a delay amount determination step for determining a delay amount for each base station device so as to be different for each base station device, and each base station device in the transmission control step When wirelessly transmitting the communication data in accordance with control, delaying wireless transmission of the communication data from the predetermined timing according to the delay amount determined in the delay amount determining step; It is characterized by including.

[0045] Further, the program according to the present invention is a program for causing a computer to function as a control device for controlling a plurality of base station devices including wireless transmission means for wirelessly transmitting communication data. A transmission control unit that wirelessly transmits the communication data at a predetermined timing from each of the plurality of base station apparatuses, and a delay that determines a delay amount for each base station apparatus so as to differ for each base station apparatus This is a program for causing the computer to function as an amount determining unit and a transmitting unit that transmits delay amount information indicating the delay amount determined by the delay amount determining unit to each base station apparatus.

The invention's effect

[0046] When the mobile station apparatus receives data transmitted from each of the plurality of base station apparatuses, delay diversity between the data transmitted by each base station apparatus is realized.

Brief Description of Drawings

FIG. 1 is a diagram showing a system configuration of a mobile communication system according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration example of a sector and a cell realized by the base station apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram for explaining forces, cell edges and sector edges according to the embodiment of the present invention.

FIG. 4 is a diagram showing functional blocks of the exchange according to the first embodiment of the present invention.

[Fig. 5] Fig. 5 is a diagram showing functional blocks of a base station apparatus that is effective in the first embodiment of the present invention.

FIG. 6 is a diagram schematically showing a plurality of subchannels used in the OFDMA standard. Enzo 77]] The eleventh practical embodiment of the present invention is powerful, and the internal relieve part is used for the insertion. It is a figure which shows the example of a replacement. .

[Environment 88]] The eleventh practical embodiment of the present invention is powerful, and the internal relieve part is used for the insertion. It is a figure which shows the example of a replacement. .

[[Fig. 99]] ((aa)) is the force that is applied to the eleventh embodiment of the present invention, and the output force from the IIFFFFTT section. It is a figure which shows the OOFFDDMM cylinder which is to be touched. . ((Bb)) is the circulation by the circulation delay delay part relating to the eleventh embodiment of the present invention.

(Sonoen 1100]] A diagram showing the functional capability of the base station apparatus installed in the twenty-second embodiment of the present invention. FIG. 11 is a diagram showing functional blocks of the base station apparatus that is powerful in the third embodiment of the present invention. 12] The base station apparatus that is powerful in the fourth embodiment of the present invention. FIG. 13 is a diagram showing functional blocks of the base station apparatus according to the fifth embodiment of the present invention. FIG. 14 is a diagram showing functional blocks of the base station apparatus according to the fifth embodiment of the present invention. It is a schematic diagram showing an example of the rotation amount set by the amount setting unit.

15] FIG. 15 is a diagram showing functional blocks of a base station apparatus that focuses on the sixth embodiment of the present invention.

FIG. 16 is a diagram illustrating an example of functional blocks of a base station apparatus adopting OFDMA and CDTD technologies.

Explanation of symbols

10, 10a switch

11 Communication data acquisition unit

12 Transmission control unit

13 Transmission area determination unit

14 Delay amount determination unit

20, 20a, 20b, 20c, 20d, 20e, 20f Base station equipment 21 Data scheduling department

22 Code selector for channel estimation

23a, 23b Mapping part

24 S / P converter

25a, 26b Inter-leave section

26 IFFT Department

27 Circular delay section

28 P / S converter

29 GI addition part

30 Mobile station equipment

41 D / A converter

42 RF section

43 Antenna

44 Delay amount setting section

45 Delay amount determiner

46a, 46b Phase rotation part

47a, 47b Rotation amount; Setting part

48 Code generator for channel estimation

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0050] FIG. 1 is a diagram showing a system configuration of a mobile communication system 1 that focuses on the present embodiment. As shown in the figure, the mobile communication system 1 includes an exchange 10, a plurality of base station devices 20, and a plurality of mobile station devices 30.

[0051] The exchange 10, the base station device 20, and the mobile station device 30 each have a computer having a CPU and a memory as a main component. The CPU implements each function according to the present embodiment by reading and executing a program stored in the memory. The memory stores various programs and data including a program for realizing the present embodiment, and also functions as a work memory for the CPU. The exchange 10 performs wired communication with a network (not shown). Further, the exchange 10 and each base station device 20 perform wired communication with each other. In the present embodiment, the exchange 10 and the base station apparatuses 20 are synchronized with each other with respect to mutual communication.

[0053] Also, each base station device 20 and each mobile station device 30 perform wireless communication with each other. In this embodiment, this wireless communication is performed in accordance with the OFDMA standard. The mobile station device 30 communicates with a communication device installed on a network (not shown) via the base station device 20 and the exchange 10.

FIG. 2 is a plan view showing a configuration example of a sector and a cell realized by each base station apparatus 20. Here, a sector realized by a certain base station apparatus 20 indicates a geographical range in which the base station apparatus 20 and the mobile station apparatus 30 can communicate. A cell is composed of sectors each realized by a plurality of base station devices 20. In FIG. 2, one cell is realized by sectors each realized by three base station apparatuses 20. In the figure, cell C1 is composed of sectors # 11, # 12, and # 13, and cells C2 to C7 are also composed of sectors # 21, # 22, # 23 to sectors # 71, # 72, and # 73. Has been.

In FIG. 2, each cell is indicated by a solid hexagon, and the three base station devices 20 constituting each cell are collectively indicated by one rectangle. In the figure, there is a portion where the overlap between cells and between sectors is described for convenience, but there is actually an overlap.

[0056] In general, one cell (for example, cell C1) is adjacent to six cells (cell C2 to cell C7), and the boundary is called a cell edge. Sectors are also adjacent to each other, and the boundary is called a sector edge. These edges point to a rough geographic area!

FIG. 3 is a diagram in which the portions of the cell C1 and the cell C2 are extracted from FIG. 2, and are diagrams for explaining the cell edge and the sector edge. For example, the cell edge connects points P3 and P4 indicating two vertices adjacent to one of the vertices of cell C2 drawn in the same hexagon among the six vertices of cell C1 drawn in a hexagon. The line and its vicinity. The sector edge is, for example, a line connecting the point P1 indicating the position of the base station device 20 and the point P2 indicating the midpoint of one of the six hexagonal sides indicating the cell C1 and its vicinity.

The exchange 10 acquires communication data for the mobile station device 30 from the network. Then, whether the acquired communication data is to be transmitted by MBMS, is transferred with the base station apparatus 20. It is determined whether it should be transmitted by one-to-one communication with the mobile station device 30.

[0059] When it is determined that the communication data is to be transmitted by one-to-one communication (hereinafter referred to as UNI data), the exchange 10 transmits one or more specific base station devices 20 (for example, destinations of communication data) Communication data is transmitted to the three base station devices 20) that realize the cell in which the station device 30 is located. The base station device 20 wirelessly transmits the UNI data received from the exchange 10 through one-to-one communication with the mobile station device 30.

[0060] On the other hand, when it is determined that the communication data is to be transmitted by MBMS (hereinafter referred to as MBMS data), the exchange 10 transmits to a plurality of base station apparatuses 20 in the MBMS data distribution area. , Send communication data. This distribution area is specified in advance by, for example, the identification number of the base station device 20. Further, the exchange 10 determines the timing at which each base station apparatus 20 wirelessly transmits MB MS data, and notifies each base station apparatus 20 of the timing.

Each base station device 20 wirelessly transmits MBMS data received from the exchange 10 at the notified timing. In this case, when each base station apparatus 20 includes a plurality of antennas, a delay of a different delay amount is given to each antenna by the CDTD technique. In the present embodiment, by determining this delay amount to be different for each base station apparatus, delay diversity between MBMS data transmitted by each base station apparatus is realized. Hereinafter, a specific configuration for this will be described in detail with reference to six embodiments. For simplicity, in each of the following embodiments, each base station apparatus 20 will be described as having only one antenna!

[First Embodiment] In this embodiment, the exchange 10a functions as a control device for controlling the delay amount for each base station device 20a. Further, in the base station device 20a, a delay in radio transmission timing is realized by a cyclic delay. Details of the cyclic delay will be described later.

[0063] FIG. 4 is a diagram showing functional blocks of the exchange 10a that is effective in the present embodiment. As shown in the figure, the exchange 10a includes a communication data acquisition unit 11, a transmission control unit 12, a transmission area determination unit 13, and a switch 15. The transmission area determination unit 13 includes a delay amount determination unit 14 therein.

[0064] FIG. 5 is a diagram showing functional blocks of the base station device 20a that are effective in the present embodiment. As shown in the figure, the base station device 20a includes a data scheduling unit 21, a channel estimation code selection unit 22, a mapping unit 23a S / P conversion unit 24, an interleaving unit 25a an IFFT unit 26, a cyclic delay unit 27 P / S conversion unit 28 GI addition unit 29 D / A conversion unit 41 RF unit 42, antenna 43, and delay amount setting unit 44. Each of these units functions as a wireless transmission unit that transmits communication data.

Communication data acquisition unit 11 (FIG. 4) acquires communication data from a network (not shown) and outputs it to switch 15. The switch 15 transmits the input communication data to each base station device 20 by performing a switching process according to the control of the transmission control unit 12 described later.

[0066] If the communication data input to switch 15 is MBMS data, transmission control unit 12 receives MBMS input from communication data acquisition unit 11 from each of a plurality of base station devices 20 at a predetermined timing. Send data wirelessly. Specifically, information indicating the transmission timing of MBMS data (referred to as MBMS transmission information) is generated and input to switch 15. Then, the switch 15 is controlled so as to transmit to the base station apparatus 20 together with the MBMS data. On the other hand, if the communication data input to the switch 15 is UNI data, the transmission control unit 12 transmits the UNI data to the cell where the mobile station device 30 that is the destination of the UNI data is located. The switch 15 is controlled so as to transmit to one or a plurality of realized base station apparatuses 20.

[0067] The transmission area determination unit 13 determines one or a plurality of base station devices 20a to which the transmission control unit 12 should transmit MBMS transmission information and MBMS data, and notifies the transmission control unit 12 of the determination. In accordance with this notification, the transmission control unit 12 controls the switch 15 to transmit MBMS transmission information and MBMS data to each base station apparatus 20a.

[0068] The delay amount determination unit 14 determines the delay amount for each base station apparatus 20a so as to be different for each base station apparatus 20a. Specifically, different delay amounts are determined for each base station device 20a. Details of this determination will be described later. The delay amount determination unit 14 generates information indicating the determined delay amount (referred to as delay amount information) for each base station device 20 a and outputs the information to the transmission control unit 12. The transmission control unit 12 sends the input delay amount information to each base station device 20a. Control switch 15 to transmit.

[0069] The base station apparatus 20a according to the present embodiment receives the MBMS data and the UNI data transmitted by the exchange 10 as described above, and performs radio transmission to the mobile station apparatus 30 according to the OFDMA standard. To do. Also, when the MBMS transmission information and the delay amount information transmitted by the exchange 10 are received and the MBMS data is wirelessly transmitted, the communication data is wirelessly transmitted according to the delay amount indicated by the received delay amount information. Delay from the timing indicated by the information. This will be specifically described below.

First, the OFDMA standard will be described. In the OFDMA standard, first, communication data is modulated by a predetermined modulation method. This modulation is performed for each predetermined modulation unit amount that differs depending on the modulation method, and a data symbol string is obtained as a result of the modulation. The data symbol sequence thus obtained is converted into a plurality of samples by inverse discrete Fourier transform. The OFDM symbol consisting of a plurality of samples is transmitted on a carrier wave.

[0071] Hereinafter, the inverse discrete Fourier transform will be described. Assuming that each data symbol constituting the data symbol sequence is d (n = 0, 1,..., N—1, where N is a number called the number of samples), as shown in Equation (1), d is assigned to each frequency (subcarrier) nf.

n 0 is applied. The N subcarriers are classified into a predetermined number of groups, and each dulp is called a subchannel.

[0072] [Equation 1] d _n e! … (1)

[0073] The baseband OFDM symbol S (t) shown in equation (2) is defined using equation (1).

B

Re [] is a symbol representing the real part of a complex number.

[0074] [Equation 2]

[0075] As shown in Equation (2), the baseband OFDM symbol S (t) has n frequencies (supports The subcarrier), each d _n is a multicarrier signal dispersion. When this is expressed in complex form, it becomes as shown in Equation (3).

[0076] [Equation 3]

[0077] When u (t) is sampled at a time interval of l / (Nf), Equation (4) is obtained. Where k =

Four

[0079] Equation (4) is in the form of inverse discrete Fourier transform. In other words, by assigning each d to a subcarrier of a different frequency, the data symbol sequence is subjected to inverse discrete Fourier transform, so that N (n) samples at a time interval of l / (Nf). Sample value u (k / Nf

0

(The real part of this sample value is called a sample.) The OFDM symbol is

0

It consists of N samples obtained in this way.

FIG. 6 is a diagram schematically showing a plurality of subchannels used in the OFDMA standard. In the example of the figure, twelve subchannels are prepared, and although not shown, each subchannel is composed of a predetermined number of subcarriers. One frame is composed of a predetermined number of time-sequential OFDM symbols. The part corresponding to each subchannel in one frame is called a block. Furthermore, the part corresponding to each OFDM symbol in one block is called a chunk. Each chunk is composed of a part of the OFDM symbol.

[0081] Also, as shown in FIG. 6, in the OFDMA standard, a mobile station device is placed at the head of each frame. In FIG. 30, a known data symbol (hereinafter referred to as a propagation path estimation symbol) obtained by modulating a known code (hereinafter referred to as a propagation path estimation code) used for estimating the propagation path characteristics.

) Is placed. In particular, in this embodiment, it is assumed that the propagation path estimation symbols are allocated to all subcarriers. That is, the data symbols constituting the OFDM symbol located at the head of each frame are all propagation path estimation symbols.

The data scheduling unit 21 receives communication data from the exchange 10 and allocates one or more subchannels to each transmission destination of the received communication data. Although the MBMS data transmission destination is not particularly defined, the data scheduling unit 21 assigns one or more subchannels to MBMS data on the assumption that there is one transmission destination.

[0083] Furthermore, the data scheduling unit 21 determines the transmission timing of communication data.

In particular, when the communication data is MBMS data, the transmission timing is determined according to the MBMS transmission information received at the same time. More specifically, based on the subchannels allocated as described above, a block to which each communication data is to be transmitted is determined, and further, a chunk in the block and the chunk are configured for each communication data of a modulation unit amount. The transmission timing of communication data is determined by determining the position of the data symbol in the data symbol sequence (a part of the OFDM symbol) to be performed. In this case, the data scheduling unit 21 excludes the position to be the propagation path estimation symbol from the position determined as the transmission timing of the communication data. The data scheduling unit 21 outputs communication data to the mapping unit 23a in accordance with the transmission timing determined as described above. Specifically, the mapping unit 23a outputs sequential communication data for each modulation unit amount at the timing when the data symbol at the determined position is generated.

[0084] The channel estimation code selection unit 22 outputs the channel estimation code at the timing when the mapping unit 23a generates the channel estimation symbol. In this case, the propagation path estimation code selection unit 22 stores a plurality of types of propagation path estimation codes, and selects a propagation path estimation code to be output according to the MBMS transmission information. Specifically, the timing for generating a propagation path estimation symbol for a block in which MB MS data is transmitted. In this case, a channel estimation code for MBMS data transmission is selected and output. On the other hand, at the timing when a propagation path estimation symbol is generated for a block to which U NI data is transmitted, a propagation path estimation code for UNI data transmission is selected and output. Here, the propagation path estimation code for MBMS data transmission is a code common to all base station apparatuses 20a, and the propagation path estimation code for UNI data transmission is an arbitrary code different for each base station apparatus 20a. Ah

The mapping unit 23a sequentially modulates the communication data input from the data scheduling unit 21 and the channel estimation code input from the channel estimation code selection unit 22 with the input timing, and the data symbols are modulated. Generate. For this modulation, use a phase modulation method such as QPSK (Quadrature Phase Shift Keying) or a quadrature amplitude modulation method such as 16QAM (16 Quadrature Amplitude Modulation). Is preferred. The mapping unit 23a sequentially outputs the generated data symbols to the S / P conversion unit 24.

[0086] The S / P conversion unit 24 holds the data symbols sequentially input from the mapping unit 23a until the number of sample data symbols are input. In other words, it holds until data symbols of lOFDM symbols are input. When all the data symbols constituting the data symbol sequence are input, the S / P conversion unit 24 outputs these data symbols in parallel to the interleaving unit 25a. By this processing, the data symbol string is mapped to the input of the IF T section 26.

[0087] Interleaving section 25a replaces the order of the data symbols input in parallel with each other based on a predetermined replacement rule, and outputs the result to IFFT section 26. FIG. 7 is a diagram illustrating an example of replacement performed by the interleaving unit 25a. In the example shown in the figure, the first input data symbol is used as the first output, and the X + first input data symbol is used as the second output. . In other words, the i-th output is ((if (t (t (1)) when i is 1 + f (t— 1) or more and f (t) or less, and i is the number of input data symbols Y or less. -l)-l) X X + t) th input data symbol. However, the function f (t) is expressed by f (0) = 0, f (t) = floor (f (t— 1) + 1 + (Y— t) / X) for non-negative integer t It is a recursive function. Floor () is the floor Is a number.

FIG. 8 is a diagram illustrating the example illustrated in FIG. 7 in the case where there are subchannels. In the example shown in the figure, 12 subchannels are prepared, and each subchannel includes 12 subcarriers. In such a case, if X shown in FIG. 7 is set to 12, the exchange is performed as shown in FIG.

[0089] IFFT section 26 performs processing on the input data symbol sequence by performing inverse fast Fourier transform processing, which is a kind of inverse discrete Fourier transform processing, to obtain an OFDM symbol including the above-mentioned number of samples, and cyclically Outputs to delay unit 27 in parallel.

The cyclic delay unit 27 gives the input OFDM symbol a cyclic delay (described later) of the delay amount set by the delay amount setting unit 44, and then outputs it to the P / S conversion unit 28.

[0091] P / S conversion unit 28 performs parallel-serial conversion on the OFDM symbol input from cyclic delay unit 27 to generate a serial signal, and outputs the serial signal to GI addition unit 29. The GI adding unit 29 adds a GI to the input OFDM symbol. Specifically, a predetermined number of samples are acquired from the end of the OFDM symbol and added to the head of OFDM. The GI addition unit 29 outputs the OFDM symbol to which the GI is added to the D / A conversion unit 41.

The processing so far is all performed by digital processing, and the amplitude of the OFDM symbol input to the D / A conversion unit 41 is indicated by a digital value. The D / A converter 41 acquires an analog signal based on this digital value and outputs it to the RF unit 42. The RF unit 42 converts the input analog signal into a signal having a radio band frequency, and transmits the signal from the antenna 43 to the radio section.

The delay amount setting unit 44 receives the delay amount information from the exchange 10, determines the delay amount based on the received delay amount information, and sets it in the cyclic delay unit 27. In a specific example, the delay amount setting unit 44 stores offset information in advance. This offset information is input by a maintenance person. For example, when there are a plurality of antennas, the offset information differs for each antenna. In this case, the maintenance person may input the offset information in the exchange 10, and the exchange 10 may notify the offset information to each base station apparatus 20. Alternatively, the maintenance person may provide the offset information in each base station apparatus 20. It is good also as inputting.

[0094] The delay amount setting unit 44 responds to the received delay amount information and the stored offset information. The delay amount is determined, and the determined delay amount is set in the cyclic delay unit 27. In a more specific example, the delay amount setting unit 44 determines the delay amount by changing the delay amount indicated by the received delay amount information according to the offset information, and sets the delay amount in the cyclic delay unit 27.

The details of the cyclic delay processing performed by the cyclic delay unit 27 will be described below.

FIG. 9A shows an OFDM symbol output from IFFT section 26. In FIG. On the other hand, (b) of the figure shows the OFDM symbol after the cyclic delay processing by the cyclic delay unit 27. FIG. As described above, one OFDM symbol is configured to include N samples. In the cyclic delay, the delay is realized by sequentially shifting the order of the samples. For example, if the delay amount is S, the kth sample that satisfies S + k≤N—1 is changed to S + kth. Also, the kth sample that satisfies S + k> N−1 is changed to S + k−Nth. As a result, the OFDM symbol received by the mobile station device 30 is configured as shown in equations (5) and (6).

[0097] [Equation 5] + A≤N—Ϊ]..-(5)

[0098] [Equation 6]

That is, the mobile station device 30 receives the OFDM symbol delayed by the delay amount S.

[0100] Next, the delay amount determined by the delay amount determination unit 14 (Fig. 4) will be described in detail.

The delay amount determination unit 14 determines the delay amount for each base station device 20a based on the arrangement of each cell and each sector. That is, the MBMS data transmitted by a plurality of base station devices 20a Since the mobile station apparatus 30 that is positioned at the cell edge or the sector edge is generally received, the delay amount determination unit 14 determines the delay between the data transmitted by the respective base station apparatuses 20 at the cell edge or the sector edge. The amount of delay for each base station apparatus 20a is determined so that the amounts are appropriately different. More specifically, the delay amount determination unit 14 manages the position, number of antennas, and directivity characteristics of the antennas provided in each base station device 20, and based on these, each base station device 20a Desirable to determine the amount of delay! /.

[0101] Also, the delay amount determination unit 14 may acquire a random value for each base station device 20a, and determine the delay amount for each base station device 20a based on the acquired random value! Yo! / Specifically, it is preferable to determine the delay amount linearly with respect to the random value. In this case, the delay amount determination unit 14 uses a plurality of random values in advance so that the delay amount for each base station device 20a becomes the same value or a value close to each other, and as a result, the effect of delay diversity cannot be obtained. Is stored, and a random value is preferably selected for each base station apparatus 20a.

[0102] In a more specific example, the delay amount determination unit 14 stores random values at N / M intervals.

Yes

Here, M is the number of base station apparatuses 20a determined by the transmission area determining unit 13, and N is the number of samples included in one OFDM symbol. Here, the random value is used as the delay amount S as it is. For example, when N = 1024 and M = 7, N 146, so the delay amount determination unit 14 stores seven random values (0, 146, 292, 438, 584, 730, 876) at 146 intervals. Keep it. Then, a random value is exclusively selected for each base station device 20a and used as a delay amount. Thereby, the delay amount of each base station apparatus 20a is appropriately determined.

[0103] Further, the delay amount determination unit 14 may determine the delay amount in consideration of the sector configuration. For example, it is preferable that the difference in delay amount between sectors is N / number of sectors 3341. In this case, 0 is assigned to the first sector, 341 is assigned to the second sector, and 682 is assigned to the third sector, and these are added to the delay amount calculated as described above. For example, if the delay amount calculated as described above is 0, the delay amount of the first sector is 0 + 0 = 0, the delay amount of the second sector is 0 + 341 = 341, Set the sector delay to 0 + 682 = 682 And decide. In this way, delay diversity is reliably realized between data transmitted in each sector.

[0104] Further, the delay amount determination unit 14 may determine the delay amount based on a random value determined for each cell and a value set in advance for each sector. In a specific example, the delay amount determination unit 14 stores a set value set in advance for each sector. For example, as described above, the set value is 0 for the first sector, 341 for the second sector, and 682 for the third sector. Further, the delay amount determination unit 14 obtains a random value for each cell and calculates a delay amount for each cell based on the random value. Then, the delay amount for each base station device 20a is calculated by adding the set value to the delay amount for each cell. In this way, it is possible to ensure a delay amount difference between cells that is relatively difficult to predict while ensuring a difference in delay amount between sectors that are relatively easy to predict.

[0105] Further, the delay amount determination unit 14 may periodically re-determine the delay amount and transmit it to each base station device 20a.

[0106] As described above, according to the present embodiment, since the communication data is transmitted after the delay amount determined to be different for each base station device 20a is transmitted, the mobile station device 30 When data transmitted from each base station apparatus 20a is received, delay diversity between the data transmitted by each base station apparatus 20a is realized.

[0107] Furthermore, since the exchange 10 determines the delay amount for each base station device 20a at once, it is possible to ensure that the delay amounts of the base station devices 20a are different from each other.

In this embodiment, the case where the exchange 10 is used as a control device has been described as! /

1S Not necessarily the exchange 10, for example, a specific base station device 20 may function as a control device. In addition, a control device separate from the exchange 10 and the base station device 20 may be provided.

[Second Embodiment] In this embodiment, a control device for determining the delay amount is not provided, and each base station device 20b determines the delay amount.

[0110] FIG. 10 is a diagram showing functional blocks of the base station device 20b which is effective in the present embodiment. As shown in the figure, the base station device 20b is the base station device 20a with a delay amount determining unit 45 added. That is, the delay amount determination unit 45 is provided in each base station device 20b. After The delay amount determination unit 45 will be described below.

[0111] The delay amount determination unit 45 determines the delay amount based on the random value. Specifically, when transmitting MBMS data, for example, for each frame, the delay amount is determined based on a random value. Then, the delay amount information indicating the determined delay amount is output to the delay amount setting unit 44. The delay amount setting unit 44 determines the delay amount in the same manner as in the first embodiment according to the delay amount information thus input, and sets it in the cyclic delay unit 27.

[0112] Note that the delay amount determination unit 45 determines the delay amount based on a random value determined for each cell and a value set in advance for each sector in the same manner as the delay amount determination unit 14. It may be. In this case, it is preferable that one of the plurality of base station devices 20b configuring one cell acquires a random value determined for each cell and notifies the other base station device 20b. is there.

According to the present embodiment, since it is not necessary to provide a control device as in the first embodiment, the system configuration is simplified.

[Third Embodiment] This embodiment is different from the first and second embodiments in the timing of giving a delay. That is, in the first and second embodiments, a cyclic delay is given after IFFT, but in this embodiment, a delay is given before IFFT.

[0115] In this case, the delay is given not by the cyclic delay but by the phase rotation. That is, the formula

(5) and Equation (6) can be transformed as Equation (7).

[0116] [Equation 7]

[0117] This is also the phase rotation of the d _n, which means that can realize a delay.

In addition, when the delay is realized by phase rotation in this way, the value of S does not necessarily have to be an integer. Therefore, by setting the phase rotation amount steplessly, the delay amount can be reduced steplessly. It is possible to set force. Therefore, in this embodiment, a cyclic delay is realized by the phase rotation of.

[0118] FIG. 11 is a diagram showing functional blocks of the base station device 20c which is effective in the present embodiment. As shown in the figure, base station apparatus 20c includes a predetermined number (number of subchannels) of phase rotation unit 46a between interleaving unit 25a and IFFT unit 26 in place of cyclic delay unit 27 in base station device 20b. In addition, a rotation amount setting unit 47a is included instead of the delay amount setting unit 44.

[0119] Interleaving section 25a outputs each data symbol to, for example, phase rotation section 46a that differs for each subchannel. Each phase rotation unit 46a rotates the phase of each data symbol input from the interleaving unit 25a according to the rotation amount input from the rotation amount setting unit 47a, and outputs it to the IFFT unit 26. More specifically, each phase rotation unit 46a adds the rotation amount input from the rotation amount setting unit 47a and the position of each data symbol in the data symbol sequence to each data symbol input from the interleaving unit 25a. (The value of n in Equation (7)) and a phase rotation of the rotation amount according to

[0120] The rotation amount setting unit 47a determines the phase rotation amount of each data symbol constituting the data symbol sequence according to the delay amount information input from the delay amount determination unit 45, and sends it to each phase rotation unit 46a. Set. In a specific example, the rotation amount setting unit 47a stores offset information in advance, similarly to the delay amount setting unit 44. This offset information is input by the maintenance person. For example, when there are a plurality of antennas, the offset information is different for each antenna. It may be different depending on the sub-channel. The rotation amount setting unit 47a determines the rotation amount for each phase rotation unit 46a according to the received delay amount information and the stored offset information, and sets the determined rotation amount to each phase rotation unit 46a. In a more specific example, the rotation amount setting unit 47a determines the rotation amount by changing the rotation amount indicated by the received delay amount information according to the offset information, and sets the rotation amount in each phase rotation unit 46a.

[0121] The processing in the rotation amount setting unit 47a will be described with a specific example. In this example, the difference in rotation between subchannels is 2π / 12. This 12 is the number of subchannels. According to this value, the offset information of the m-th subchannel is (2π / 1 2) X (m−1). Delay amount determination unit 45 The time indicated by the delay amount information input by 45 If the amount of rotation S is 2π / Ν, for example, the rotation amount setting unit 47a sets the rotation amount of the first subchannel to 2π / Ν + 0 and the rotation amount of the second subchannel to 2π / Ν. The rotation amount S of each subchannel is determined in such a manner as + 2π / 12. In this way, when transmitting the same MBMS data to multiple subchannels! /, Delay diversity can be appropriately achieved even between MBMS data transmitted on each subchannel. Is done.

[0122] As described above, according to this embodiment, each mobile station device 30c receives data transmitted from each base station device 20c! Thus, delay diversity between the transmitted data is realized.

In this embodiment, in base station apparatus 20b, instead of cyclic delay unit 27, a predetermined number of phase rotation units 46a are added between interleaving unit 25a and IFFT unit 26, and a delay amount setting unit In the force base station apparatus 20a described in the configuration including the rotation amount setting unit 47a instead of 44, a predetermined number of phase rotation units 46a are added between the interleave unit 25a and the IFFT unit 26 instead of the cyclic delay unit 27. Of course, the same effect as described above can be obtained by including the rotation amount setting unit 47a instead of the delay amount setting unit 44.

[Fourth Embodiment] This embodiment is different from the first to third embodiments in the configuration related to the propagation path estimation code. That is, in the first to third embodiments, the MBMS data transmission channel estimation code common to all the base station apparatuses 20a is used for the block to be transmitted by MBMS, but in this embodiment, Also, a block for performing transmission by MBMS uses a different channel estimation code for UNI data transmission for each base station apparatus 20a. In this way, an arbitrary code can be used as a propagation path estimation code, but the contents of subcarriers received by the mobile station device 30 from the plurality of base station devices 20 are different from each other. It becomes impossible to receive. Therefore, in the present embodiment, a configuration for enabling the mobile station device 30 to receive each subcarrier from the plurality of base station devices 20 while allowing an arbitrary code to be used as a channel estimation code. Indicates.

[0125] Fig. 12 is a diagram showing functional blocks of the base station device 20d, which focuses on the present embodiment. As shown in the figure, in the base station device 20d, the base station device 20c replaces the propagation channel estimation code selection unit 22 and the mapping unit 23a with a propagation channel estimation code generation unit 48 and a map pin. And include the 23b section!

[0126] The channel estimation code generator 48 generates and outputs an arbitrary channel estimation code at the timing when the mapping unit 23a generates a channel estimation symbol.

[0127] Mapping section 23b, for each subcarrier, is based on the propagation path estimation code input from propagation path estimation code selection section 22! Depending on the phase of the propagation path estimation symbol, the communication data input from the data scheduling unit 21 is phase-modulated with one or more data symbols in this order to the S / P conversion unit 24. Output sequentially.

[0128] Specifically, the mapping unit 23b sequentially transmits the communication data input from the data scheduling unit 21 and the channel estimation code input from the channel estimation code selection unit 22 at the input timing. Modulate and generate data symbols. The data is sequentially output to the S / P converter 24. In this case, the mapping unit 23b holds the phase of the data symbol that is a propagation path estimation symbol included in the head of each subcarrier while generating a plurality of data symbols for one block. . Then, for each subcarrier, the subsequent communication data is phase-modulated according to the phase of the propagation path estimation symbol arranged at the head.

More specifically, mapping section 23b holds a reference phase common to all base station apparatuses 20a, and calculates a phase difference between the reference phase and the phase of the propagation path estimation symbol. Then, the phase of the subsequent data symbol generated according to the communication data is rotated according to the calculated phase difference.

[0130] As described above, according to the present embodiment, even if the propagation path estimation code differs between base station apparatuses 20, a data symbol sequence transmitted from a base station apparatus 20 Since the data symbol 歹 IJ transmitted by the base station device of the mobile station device 30 can be in the same state as when only a constant phase rotation is received as a whole, the mobile station device 30

20 can receive the transmitted data symbol sequence. In other words, the mobile station device 30 can receive each subcarrier from a plurality of base station devices 20 power while allowing an arbitrary code to be used as a channel estimation code.

[Fifth Embodiment] In each of the above embodiments, the propagation path estimation code is set for each frame. And included in each subcarrier. In this case, the mobile station device 30 can estimate the propagation path state for each subcarrier and use the estimation result for reception of communication data. In a specific example, the reception timing is acquired based on the propagation path estimation code, and communication data is received according to the reception timing.

On the other hand, in the present embodiment, propagation path estimation symbols are arranged only in some of the subcarriers. Specifically, a predetermined number of subcarriers are grouped (hereinafter, this group is referred to as a subcarrier group), and one of a plurality of subcarriers constituting each group is used for channel estimation. A sign shall be included. Each of the subcarrier groups may be a subchannel or may be grouped according to a different standard from the subchannel! /. The mobile station apparatus 30 uses the propagation path state of another subcarrier in order to estimate the propagation path state of a certain subcarrier.

[0133] In the third and fourth embodiments, a phase rotation with a different rotation amount is given to each subcarrier. That is, each d is given a phase rotation of e ^{j27t nS / N} , and the amount of rotation varies depending on n. If the amount of rotation is different, an appropriate channel state is not acquired even if the channel state of another subcarrier is acquired based on the channel state of a certain subcarrier. Therefore, in this embodiment, the rotation amount is unified within the subcarrier group.

FIG. 13 is a diagram showing functional blocks of the base station device 20e that are effective in the present embodiment. As shown in the figure, the base station device 20e includes a phase rotation unit 46b and a rotation amount setting unit 47b in place of the phase rotation unit 46a and the rotation amount setting unit 47a in the base station device 20c. ing.

[0135] The rotation amount setting unit 47b determines the phase rotation amount for each subcarrier group according to the delay amount information input from the delay amount determination unit 45. The rotation amount setting unit 47b sets the rotation amount for each subcarrier group thus generated in each phase rotation unit 46b.

[0136] Each phase rotation unit 46b gives each data symbol a phase rotation of the rotation amount set by each phase rotation unit 46b. As a result, the delay amount indicated by the delay amount information and the subcarrier group to which the subcarrier used for radio transmission of each data symbol belongs. A corresponding amount of phase rotation is applied to each data symbol. That is, the phase rotational force S of the rotation amount unified within the subcarrier group is given to each data symbol. Hereinafter, a specific example will be described.

FIG. 14 shows an example of the rotation amount set by the rotation amount setting unit 47b when there are 12 subcarriers in one subchannel and when these subcarriers are grouped by four. It is a schematic diagram shown. The rotation amount setting unit 47b sets three rotation amounts W 1, W 2 and W in each phase rotation unit 46b. Where m is the subchannel number. Each

m0 ml πι2

In response to this setting, the phase rotation unit 46b rotates the phase of the rotation amount W for the subcarriers belonging to the first subcarrier group and the subcarriers belonging to the second subcarrier group.

mO

For the rear, the phase rotation of the rotation amount W, the subkey belonging to the third subcarrier group

ml

For the carrier, a phase rotation of the rotation amount unified within the subcarrier group is given, such as a phase rotation of the rotation amount W.

[0138] Next, the mutual relationship between the subcarrier groups in the rotation amount for each subcarrier group generated by the rotation amount setting unit 47b will be described.

[0139] Similar to the rotation amount setting unit 47a, the rotation amount setting unit 47b stores offset information in advance, and the rotation amount setting unit 47b for each phase rotation unit 46a according to the received delay amount information and the stored offset information. Determine the amount of rotation. Here, as in the third embodiment, the offset information of the m-th subchannel is (2 兀 / 12) X (m−1). As a result, the rotation amount setting unit 47b calculates a different rotation amount for each subchannel according to the received delay amount information and the stored offset information by the same processing as in the third embodiment. Become. Let S be the amount of rotation.

m

[0140] The offset information of the present embodiment includes a difference ΔX in the amount of rotation between the subcarrier groups. The rotation amount setting unit 47b is based on the rotation amounts S and ΔΧ calculated as described above.

m

Then, the rotation amount of each subcarrier group is calculated. For example, in the above example, w mO = s

, W = S + Δ Χ, λ ¥ = S + 2 Δ Χ. In this case, the difference Δ Χ is expressed as m ml m m2 m

It's also good to make it different between the sub-Cyanenoles, and it's also good to unify.

[0141] Also, in particular, when the difference amount ΔΧ is unified between subchannels, the difference in rotation amount between adjacent subcarrier groups between subchannels may be ΔΧ, or greater than ΔΧ. It may be a large value. For example, in the above example, the difference between W and W (S) — (S + 2 Δ Χ) =

2 π / ΐ 2— 2 Δ You can decide Δ X so that it becomes Δ X! /, And you can decide Δ X so that it is bigger than Δ X! /. In the former case, Δ Χ = 2π / 36, and in the latter case, ΔΧ <2π / 36. If the value is larger than ΔΧ, the cross-correlation between adjacent subchannels can be reduced.

[0142] As described above, according to the present embodiment, the amount of phase rotation can be unified within a subcarrier group, so that only one of a plurality of subcarriers constituting a subcarrier group is used for channel estimation. Even when the code is included, the mobile station device 30 can appropriately acquire the propagation path state of each subcarrier.

[Sixth Embodiment] It is known that when cyclic delay transmission is performed, a valley of received power occurs in a frequency width corresponding to the delay amount. For this reason, when a data symbol is transmitted to a certain user using a plurality of subcarriers, if the frequency width between the plurality of subcarriers exactly matches the above frequency width, the user is notified. In contrast, any data symbol transmitted to the receiver will be received with its reception power lowered, which is undesirable. Therefore, in the present embodiment, a configuration is shown in which the frequency width between subcarriers used for data symbol transmission to a certain user does not coincide with the above frequency width in which a valley of received power is generated.

[0144] FIG. 15 is a diagram illustrating functional blocks of the base station device 20f, which focuses on the present embodiment. As shown in the figure, the base station device 20f includes an interleave unit 25b in place of the interleave unit 25a in the base station device 20a.

[0145] The interleaving unit 25b acquires the delay amount set in the cyclic delay unit 27 by the delay amount setting unit 44. Then, the order of each data symbol input in parallel from the S / P converter 24 is changed based on the replacement rule corresponding to the acquired delay amount, and then output to the IFFT unit 26.

That is, by the above replacement, the subcarriers included in one subchannel are dispersed with a frequency width according to the replacement rule. Therefore, the interleave unit 25b determines a replacement rule to be used so that the frequency width does not match the frequency width according to the delay amount. [0147] Since each base station apparatus 20f performs this determination process, if the delay amount differs between sectors or cells, the determined replacement rule also differs between sectors or cells.

[0148] Also, the base station device 20f wirelessly transmits to the mobile station device 30 a control signal indicating an applied replacement rule, using a control signal transmission unit (not shown). When the mobile station device 30 receives this control signal, the mobile station device 30 subjects the received data symbol string to a dingering process based on the replacement rule indicated by the control signal.

[0149] As described above, according to the present embodiment, the frequency width between subcarriers used for data symbol transmission to a certain user does not match the above-described frequency width in which the valley of received power occurs! /, Do it with power S.

[0150] It should be noted that a program for realizing the functions of the exchange 10a and the base station devices 20a to 20f is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into the computer system. The above processes may be performed by executing.

The “computer system” here may include an OS and hardware such as peripheral devices. In addition, this “computer system” includes a homepage provision environment (or display environment) if a WWW system is used.

[0152] "Computer-readable recording medium" refers to a flexible disk, a magneto-optical disk, a writable nonvolatile memory such as a ROM and a flash memory, a portable medium such as a CD-ROM, and a built-in computer system. A storage device such as a hard disk.

[0153] Further, the "computer-readable recording medium" includes a volatile property inside a computer system that becomes a server or a client when a program is transmitted via a communication line such as a network such as the Internet or a telephone line. It also includes those that hold programs for a certain period of time, such as memory (for example, DRAM (Dynamic Random Access Memory)).

[0154] In addition, the above program may be transmitted from a computer system storing the program in a storage device or the like to another computer via a transmission medium or by transmission waves in the transmission medium. It may be transmitted to the system. Here, the “transmission medium” for transmitting the program is a medium having a function of transmitting information such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line! /, Yeah.

[0155] Furthermore, the program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve each function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be used.

It should be noted that the present invention is not limited to the embodiments described above, and those appropriately modified in design without departing from the gist of the present invention are also included in the technical scope of the present invention. Availability of

[0157] When the mobile station apparatus receives data transmitted from each of a plurality of base station apparatuses, the present invention can be applied to the case where delay diversity is achieved between data transmitted by each base station apparatus.

Claims

The scope of the claims

[1] A mobile communication system including a plurality of base station devices each including wireless transmission means for wirelessly transmitting communication data to a mobile station device,

Transmission control means for wirelessly transmitting the communication data from each of the plurality of base station devices at a predetermined timing;

A delay amount determining means for determining a delay amount for each base station device so as to be different for each base station device;

Including

Each base station apparatus wirelessly transmits the communication data by the wireless transmission unit according to the control of the transmission control unit, and the communication data according to the delay amount determined by the delay amount determination unit. The mobile communication system is characterized in that the wireless transmission is delayed from the predetermined timing.

[2] In the mobile communication system according to claim 1,

The wireless transmission means includes

An inverse discrete Fourier transform unit for performing an inverse discrete Fourier transform process on a data symbol sequence composed of a plurality of data symbol forces each modulated by the communication data, and a sample sequence obtained as a result of the inverse discrete Fourier transform process by radio transmission A wireless transmitter

Including

Each base station apparatus wirelessly transmits the communication data by the wireless transmission means according to the control of the transmission control means, and the inverse discrete Fourier according to the delay amount determined by the delay amount determination means. A mobile communication system characterized by delaying wireless transmission of the communication data from the predetermined timing by cyclically delaying a sample sequence obtained as a result of the conversion process.

[3] In the mobile communication system according to claim 1,!

The wireless transmission means includes

An inverse discrete Fourier transform unit that performs an inverse discrete Fourier transform process on a data symbol sequence composed of a plurality of data symbol forces each of which modulates the communication data; A wireless transmission unit that wirelessly transmits a sample sequence obtained as a result of the inverse discrete Fourier transform process;

Including

Each of the base station devices, when wirelessly transmitting the communication data by the wireless transmission means according to the control of the transmission control means, the data symbol sequence according to the delay amount determined by the delay amount determination means By rotating the phase of each of the plurality of data symbols that constitutes, the wireless transmission of the communication data is delayed from the predetermined timing.

A mobile communication system.

[4] In the mobile communication system according to claim 1,! /

The wireless transmission means includes

Including

Each of the base station devices is grouped according to the delay amount determined by the delay amount determination unit when the communication data is wirelessly transmitted by the wireless transmission unit according to the control of the transmission control unit. The wireless transmission of the communication data is delayed from the predetermined timing by rotating the phase of each of the plurality of data symbols constituting the data symbol sequence for each group.

A mobile communication system.

[5] The mobile communication system according to claim 3 or 4,

Each of the base station devices gives each data symbol a phase rotation of a rotation amount according to the delay amount determined by the delay amount determining means and the position of each data symbol in the data symbol sequence.

A mobile communication system.

[6] In the mobile communication system according to any one of claims 2 to 5, The wireless transmission means includes

An interleaving unit that replaces the position of each data symbol in the data symbol sequence with a replacement rule according to a delay amount determined by the delay amount determining unit, and inputs the inverted symbol to the inverse discrete Fourier transform unit;

including,

A mobile communication system.

[7] In the mobile communication system according to any one of claims 1 to 6,

The mobile communication system is

A control device for controlling each of the base station devices;

Including

The delay amount determining means is provided in the control device,

The controller is

Transmitting means for transmitting delay amount information indicating the delay amount determined by the delay amount determining means to each of the base station devices;

Including

Each of the base station devices, when wirelessly transmitting the communication data by the wireless transmission unit according to the control of the transmission control unit, according to the delay amount information received from the control device, A mobile communication system characterized by delaying wireless transmission of data from the predetermined timing.

[8] In the mobile communication system according to claim 7,

The delay amount determining means determines a delay amount based on a random value.

A mobile communication system.

[9] In the mobile communication system according to any one of claims 1 to 6,

The delay amount determining means is provided in each of the plurality of base station apparatuses, and determines the delay amount based on random values.

A mobile communication system.

[10] The mobile communication system according to claim 8 or 9,

The delay amount determining means is set in advance for each sector and a random value determined for each cell. The amount of delay is determined based on

A mobile communication system.

[11] In the mobile communication system according to claim 1,!

The wireless transmission means wirelessly transmits one known data symbol obtained by modulating known data and one or a plurality of data symbols obtained by modulating the communication data according to the phase of the known data symbol.

A mobile communication system.

[12] In the mobile communication system according to claim 1,! /

The wireless transmission means wirelessly transmits one known data symbol obtained by modulating known data unified between the base station devices and one or more data symbols obtained by modulating the communication data.

A mobile communication system.

[13] A control device for controlling a plurality of base station devices each including wireless transmission means for wirelessly transmitting communication data,

Transmission means for transmitting delay amount information indicating the delay amount determined by the delay amount determination means to each of the base station devices;

The control apparatus characterized by including.

[14] A base station apparatus control method for controlling a plurality of base station apparatuses each including wireless transmission means for wirelessly transmitting communication data,

A transmission control step of wirelessly transmitting the communication data at a predetermined timing from each of the plurality of base station devices;

A delay for determining a delay amount for each base station apparatus so that the base station apparatuses differ from one base station apparatus to another. Each base station apparatus transmits the communication data according to control in the transmission control step. When wirelessly transmitting, delaying wireless transmission of the communication data from the predetermined timing in accordance with the delay amount determined in the delay amount determining step;

A base station apparatus control method comprising:

[15] A program for causing a computer to function as a control device for controlling a plurality of base station devices each including wireless transmission means for wirelessly transmitting communication data, each from the plurality of base station devices, Transmission control means for wirelessly transmitting the communication data at a predetermined timing;

A delay amount determining means for determining a delay amount for each base station device, so as to be different for each base station device; and

A program for causing the computer to function as