WO2010122749A1 - Système de communication, appareil de communication et procédé de communication - Google Patents

Système de communication, appareil de communication et procédé de communication Download PDF

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Publication number
WO2010122749A1
WO2010122749A1 PCT/JP2010/002748 JP2010002748W WO2010122749A1 WO 2010122749 A1 WO2010122749 A1 WO 2010122749A1 JP 2010002748 W JP2010002748 W JP 2010002748W WO 2010122749 A1 WO2010122749 A1 WO 2010122749A1
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WIPO (PCT)
Prior art keywords
reference symbol
feedback information
transmission
base station
symbol sequence
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PCT/JP2010/002748
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English (en)
Japanese (ja)
Inventor
示沢寿之
野上智造
山田昇平
平川功
加藤恭之
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シャープ株式会社
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Publication of WO2010122749A1 publication Critical patent/WO2010122749A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/0022—PN, e.g. Kronecker
    • H04J13/0025—M-sequences
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
    • H04J11/0023—Interference mitigation or co-ordination
    • H04J11/005—Interference mitigation or co-ordination of intercell interference
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/261—Details of reference signals
    • H04L27/2613—Structure of the reference signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0014—Three-dimensional division
    • H04L5/0023—Time-frequency-space
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0032—Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0032—Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
    • H04L5/0035—Resource allocation in a cooperative multipoint environment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0204—Channel estimation of multiple channels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/022—Channel estimation of frequency response
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0226—Channel estimation using sounding signals sounding signals per se
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0058—Allocation criteria
    • H04L5/006—Quality of the received signal, e.g. BER, SNR, water filling

Definitions

  • the present invention relates to a communication system, a communication apparatus, and a communication method.
  • This application claims priority based on Japanese Patent Application No. 2009-106250 filed in Japan on April 24, 2009, the contents of which are incorporated herein by reference.
  • a cellular (cell) in which a plurality of areas covered by a base station (transmitting station, transmitting device, eNodeB) are arranged in a cell (Cell)
  • a base station transmitting station, transmitting device, eNodeB
  • the communication area can be expanded.
  • mobile terminals receiving station, mobile station, receiving device, UE; User Equipment
  • communication can be performed without receiving interference of transmission signals from a plurality of base station apparatuses, there has been a problem that frequency utilization efficiency is low.
  • Non-Patent Document 1 discloses a CoMP (Cooperative Multipoint) transmission system as such a system.
  • joint processing Joint Processing
  • joint transmission Joint transmission
  • Scheduling Coordinated Scheduling
  • Beamforming beamforming
  • Non-Patent Document 2 shows a method of performing these controls.
  • FIG. 22 is a diagram illustrating an example in which the mobile terminal 1050 transmits the feedback information IFB to the base station 1001 using the reference signal RS transmitted from the base station 1001.
  • a reference signal RS is transmitted from the base station 1001 to the mobile terminal 1050, and the mobile terminal 1050 transmits feedback information IFB generated based on the reference signal RS to the base station 1001.
  • a reference signal (RS; Based on Reference Signal, pilot signal, known signal) RS
  • the mobile terminal 1050 estimates the transmission path condition of the downlink, and the uplink (uplink) that performs data transmission from the mobile terminal 1050 to the base station 1001 It is conceivable to transmit (feedback) the estimated transmission path condition or the like to the base station 1001.
  • FIG. 23 is a diagram illustrating an example of a reference signal (reference symbol) RS transmitted by the base station 1001.
  • the horizontal axis indicates the time direction
  • the vertical axis indicates the frequency direction
  • each square indicates a resource element
  • the shaded square indicates a resource element to which the reference signal RS is mapped.
  • the reference signal RS is: As shown in the figure, a reference signal scattered (scattered) in resource elements in the frequency direction and the time direction can be used.
  • feedback information IFB As information (feedback information IFB) generated based on this reference signal RS and fed back to the base station 1001, recommended transmission format information (CQI (Channel Quality Indicator), RI (Rank Indicator), PMI (Precoding Matrix Index) )) Etc. can be used.
  • CQI Channel Quality Indicator
  • RI Rank Indicator
  • PMI Precoding Matrix Index
  • the present invention has been made in view of the above problems, and an object thereof is a communication system, a communication apparatus, and a communication method capable of efficiently obtaining appropriate feedback information in a communication system capable of performing cooperative communication. Is to provide.
  • the present invention has been made to solve the above-described problem, and a communication system according to an aspect of the present invention generates a reference signal sequence for generating a transmission side reference symbol sequence that is a sequence of reference symbols based on a pseudo-noise sequence.
  • a generation unit a resource element mapping unit that maps transmission data and the transmission-side reference symbol sequence to one or a plurality of resource elements for each one or a plurality of symbols, and shows the transmission data and the transmission-side reference symbol sequence
  • a first wireless transmission unit that generates and transmits a transmission signal of a wireless signal according to the mapping, a first wireless reception unit that receives feedback information based on a signal reception state of the reference symbol, and a mode of transmission of the transmission data
  • a first communication device including a feedback information processing unit that controls based on the feedback information;
  • a second radio reception unit that receives the radio signal; and a signal reception state from the first communication device is measured based on a reference symbol sequence extracted from the received radio signal, and the signal reception state is measured according to the measured signal reception state
  • a second communication device including a feedback information generation unit that generates feedback information and a second wireless transmission unit that transmits the feedback information;
  • the transmission mode refers to a coding rate for encoding transmission data, a modulation scheme, a
  • a communication system is the communication system described above, and is included in a third radio reception unit that receives the transmission signal, and a despread reference symbol sequence extracted from the transmission signal.
  • a feedback information generating unit that measures a signal reception state from the first communication device based on a reference symbol to be generated, generates feedback information according to the measured signal reception state, and a third wireless transmission unit that transmits the feedback information;
  • a third communication device including: In this communication system, the second communication device that despreads the reference symbol sequence before despreading and generates feedback information is the same as the third communication device that generates feedback information based on each reference symbol without despreading. Since the reference symbol is referred to, both communication apparatuses can be mixed without increasing the resource overhead due to the reference symbol.
  • a communication system is the communication system described above, and includes a plurality of the first communication devices, and resource element mapping units of the plurality of first communication devices are the same resource elements.
  • the transmission side reference symbol sequence is mapped for each symbol.
  • the second communication device since reference symbols are mapped to the same resource elements between adjacent first communication devices, the second communication device despreads the reference symbol sequence before despreading, so that the other first communication devices Interference due to the reference signal can be suppressed or reduced.
  • a communication system is the communication system described above, wherein the transmission-side reference symbol sequence generated by the reference signal generation unit is a transmission-side reference symbol sequence of another first communication device.
  • Orthogonal to Here, a code sequence orthogonal to each other from an orthogonal code sequence such as a Walsh code, an OVSF code, and a Hadamard code can be used as a transmission-side reference symbol sequence orthogonal to the transmission-side reference symbol sequence of another first communication apparatus.
  • the orthogonal reference symbol sequence is used in the first communication device, the cross-correlation is excellent, and the second communication device despreads the reference symbol sequence before despreading from other first communication devices. The effect of suppressing or reducing interference is great.
  • a communication system is the communication system described above, and includes a plurality of the first communication devices, and the transmission side generated by a reference signal generation unit of the plurality of first communication devices.
  • the reference symbol series are cyclically shifted from each other.
  • the transmission side reference symbol sequence shifted cyclically between the first communication devices is used, when the second communication device despreads the reference symbol sequence before despreading, due to the autocorrelation of the sequence The effect of suppressing or reducing interference from other first communication devices can be obtained.
  • a communication system is the communication system described above, and includes a plurality of the first communication devices, and resource element mapping units of the plurality of first communication devices have different resource elements. Map the reference symbols.
  • reference symbols are mapped to resource elements that are different from each other between adjacent first communication devices. Therefore, when the second communication device despreads the reference symbol sequence before despreading, Interference due to transmission data can be suppressed or reduced.
  • a communication apparatus includes a reference signal generation unit that generates a transmission-side reference symbol sequence that is a sequence of reference symbols based on a pseudo-noise sequence, transmission data, and the transmission-side reference symbol sequence, A resource element mapping unit that maps one to a plurality of resource elements for each one or a plurality of symbols, and a radio transmission unit that generates and transmits a radio signal indicating the transmission data and the transmission side reference symbol sequence according to the mapping And a first wireless reception unit that receives feedback information based on a signal reception state of the reference symbol, and a feedback information processing unit that controls a transmission method of the transmission data based on the feedback information. Since this communication device transmits a radio signal indicating a reference symbol sequence based on a pseudo-noise sequence, feedback information obtained by despreading this reference symbol sequence and suppressing or reducing interference from other communication devices is used. Therefore, appropriate control can be performed.
  • a communication apparatus includes a radio reception unit that receives a radio signal indicating a transmission-side reference symbol sequence via a propagation path, and a reference symbol sequence extracted from the received radio signal.
  • a feedback information generation unit that measures a signal reception state based on the signal reception state and generates the feedback information according to the measured signal reception state, and a wireless transmission unit that transmits the feedback information.
  • the communication apparatus can suppress or reduce interference from a communication apparatus other than the desired communication apparatus using the reference symbol sequence, and generate more appropriate feedback information.
  • the first communication device in the communication system in which the first communication device and the second communication device perform wireless communication, is a reference symbol sequence based on a pseudo-noise sequence.
  • a reference signal generation process for generating a certain reference symbol sequence on the transmission side, and a resource element in which the first communication device maps transmission data and the reference symbol sequence on the transmission side to one or more resource elements for each one or more symbols A mapping process; a first radio transmission process in which the first communication apparatus generates and transmits a radio signal indicating the transmission data and the transmission-side reference symbol sequence according to the mapping; and the first communication apparatus transmits the reference symbol.
  • the third communication device communicates with the first communication device.
  • a reference signal generation process in which the first communication device generates a transmission-side reference symbol sequence that is a sequence of reference symbols based on a pseudo-noise sequence, and the first communication device sets transmission data and the transmission-side reference symbol sequence to 1 to 1
  • a resource element mapping process for mapping to one or a plurality of resource elements for each of a plurality of symbols, and the first communication apparatus generates and transmits a radio signal indicating the transmission data and the transmission side reference symbol sequence according to the mapping
  • a first wireless transmission process and the first communication device receives feedback information based on a signal reception state of the reference symbol.
  • Measuring a signal reception state from the first communication device based on a process and a reference symbol sequence extracted from the radio signal received by the second communication device, and generating the feedback information according to the measured signal reception state A feedback information generation process, a second radio transmission process in which the second communication apparatus transmits the feedback information, a third radio reception process in which the third communication apparatus receives the transmission signal, and the third communication apparatus
  • the signal received from the first communication device is measured based on a reference symbol extracted from the transmission signal, and the measured signal
  • the second communication device and the third communication device can refer to the same reference symbol, and both communication devices can be mixed without increasing the resource overhead due
  • a communication method includes a reference signal generation process in which a communication apparatus generates a transmission-side reference symbol sequence that is a sequence of reference symbols based on a pseudo-noise sequence, transmission data, and the transmission-side reference.
  • a resource element mapping process for mapping a symbol sequence to one or a plurality of resource elements for each one or a plurality of symbols, and generating and transmitting a radio signal indicating the transmission data and the transmission side reference symbol sequence according to the mapping
  • a wireless transmission process ; a wireless reception process for receiving feedback information based on a signal reception state of the reference symbol; and a feedback information processing process for controlling a transmission method of the transmission data based on the feedback information.
  • a communication method includes a wireless reception process in which a communication device receives a wireless signal indicating a transmission-side reference symbol sequence via a propagation path, and the wireless signal received by the communication device.
  • this communication method it is possible to suppress or reduce interference from a communication apparatus other than a desired communication apparatus using a reference symbol sequence, and generate more appropriate feedback information.
  • FIG. 1 It is a schematic block diagram which shows the structure of the communication system in the 1st Embodiment of this invention. It is a schematic block diagram which shows the structural example of the communication system which does not include the mobile terminal device which performs the cooperative communication in the embodiment. It is a schematic block diagram which shows the structural example of the communication system which does not include the mobile terminal device which does not perform cooperative communication in the embodiment. It is a schematic block diagram which shows the structure of the base station apparatus 100 in the embodiment. 4 is a conceptual diagram showing an example in which resource element mapping units 301 to 30T map reference symbol sequences for four antenna ports in the same embodiment. FIG. It is a schematic block diagram which shows the structure of the mobile terminal device 150 in the embodiment.
  • FIG. 4 is a conceptual diagram illustrating an example of a reference symbol sequence used by the base station apparatus 100 for an antenna port 1 in the embodiment.
  • FIG. 10B is a conceptual diagram showing an example in which the base station apparatus 100 maps the reference symbol sequence of FIG. 10A in the same embodiment.
  • FIG. 10B is a conceptual diagram showing an example in which the base station device 101 maps the reference symbol sequence obtained by cyclically shifting the reference symbol sequence of FIG. 10A to the same resource element as the base station device 100 in the embodiment.
  • FIG. 10 is a conceptual diagram illustrating an example in which the base station apparatus 100 maps reference symbol sequences in the same embodiment as in FIG. 10B.
  • the base station apparatus 101 is a conceptual diagram showing an example in which a reference symbol sequence is mapped to resource elements shifted by one subcarrier in the frequency direction from the position shown in FIG. 10C.
  • the base station apparatus 100 is a conceptual diagram which shows the example which mapped the reference symbol series of the added antenna port.
  • the base station apparatus 100 is a conceptual diagram showing another example in which a reference symbol sequence of an added antenna port is mapped.
  • FIG. 3 is a conceptual diagram illustrating an example of a 4-chip reference symbol sequence assigned to the antenna port 5 by the base station apparatus 100 in the embodiment.
  • FIG. 13B is a conceptual diagram showing an example in which the base station apparatus 100 maps the reference symbol sequence of FIG. 13A in the same embodiment.
  • FIG. 13B is a conceptual diagram illustrating an example in which the base station device 101 maps the reference symbol sequence obtained by cyclically shifting the reference symbol sequence of FIG. 13A to the same resource element as the base station device 100 in the embodiment.
  • FIG. 14 is a conceptual diagram illustrating an example in which the base station apparatus 100 maps reference symbol sequences in the same embodiment as in FIG.
  • the base station apparatus 101 is a conceptual diagram showing an example in which a reference symbol sequence is mapped to a resource element shifted by one subcarrier in the frequency direction from the position shown in FIG. 13C.
  • it is a conceptual diagram which shows the example of the reference symbol series of 4 chips
  • FIG. it is a conceptual diagram which shows the example which the base station apparatus 100 mapped the reference symbol series.
  • the base station apparatus 101 maps the reference symbols of the antenna ports 1 to 4 by shifting in the frequency direction with respect to the mapping of the base station apparatus 100, and the reference symbol sequence of the antenna port 5 is the base station apparatus 100.
  • FIG. 4 is a conceptual diagram illustrating an example in which a base station apparatus 100 maps a reference symbol sequence of an antenna port 6 in the embodiment.
  • FIG. 4 is a conceptual diagram illustrating an example in which the base station apparatus 100 maps a reference symbol sequence of an antenna port 7 in the embodiment.
  • FIG. 4 is a conceptual diagram illustrating an example in which a base station apparatus 100 maps a reference symbol sequence of an antenna port 8 in the embodiment.
  • FIG. 4 is a conceptual diagram illustrating an example in which a base station apparatus 100 maps a reference symbol sequence of an antenna port 6 in the embodiment.
  • FIG. 4 is a conceptual diagram illustrating an example in which the base station apparatus 100 maps a reference symbol sequence of an antenna port 7 in the embodiment.
  • FIG. 4 is a conceptual diagram illustrating an example in which a base station apparatus 100 maps a reference symbol sequence of an antenna port 8 in the embodiment.
  • FIG. 1 It is a conceptual diagram which shows the example which the base station apparatus 100 mapped the reference symbol series for 1 series to the some resource block in the frequency direction in the 6th Embodiment of this invention. It is a conceptual diagram which shows the example which the base station apparatus 100 mapped the reference symbol sequence for 1 sequence to the some resource block in the time direction in the 7th Embodiment of this invention. It is a conceptual diagram which shows the example which the base station apparatus 100 mapped the reference symbol sequence for 1 series to the some antenna port in the 8th Embodiment of this invention. In the 9th Embodiment of this invention, it is a conceptual diagram which shows the example of the reference symbol series based on the orthogonal code series which the base station apparatuses 100 and 101 use with respect to the antenna port 1.
  • FIG. 1 It is a conceptual diagram which shows the example which the base station apparatus 100 mapped the reference symbol series for 1 series to the some resource block in the frequency direction in the 6th Embodiment of this invention. It is a conceptual diagram which shows the example which the
  • FIG. 4 is a conceptual diagram illustrating an example of a reference symbol sequence based on an orthogonal code sequence used by the base station apparatuses 100 and 101 for the antenna port 2 in the embodiment.
  • FIG. In the embodiment it is a conceptual diagram which shows the example which the base station apparatus 100 mapped the reference symbol series. In the embodiment, it is a conceptual diagram which shows the example which the base station apparatus 101 mapped the reference symbol series. It is a figure which shows the example which a mobile terminal transmits feedback information to a base station apparatus using the reference signal reference-transmitted from a base station. It is a figure which shows the example of the reference signal which a base station transmits.
  • FIG. 1 is a schematic configuration diagram showing a configuration of a communication system 900 according to the first embodiment of the present invention.
  • the communication system 900 in FIG. 1 includes base station devices (communication device, first communication device, transmission device, cell, transmission point, transmission antenna group) 100 and 101 and mobile terminal devices (reception device, reception terminal) 150 and 151. Consists of including.
  • Base station apparatus 100 and base station apparatus 101 are base stations adjacent to each other, and some of the cells overlap.
  • the mobile terminal device 150 (communication device, second communication device) is located at the cell edge between the base station device 100 and the base station device 101, and performs cooperative communication with both base station devices 100 and 101.
  • the mobile terminal apparatus 151 (third communication apparatus) is located near the cell center of the base station apparatus 100 and communicates with the base station apparatus 100 without performing cooperative communication.
  • this invention includes the case where only either one of the mobile terminal apparatus 150 which performs cooperative communication, and the mobile terminal apparatus 151 which does not perform cooperative communication is included.
  • FIG. 2 is a schematic configuration diagram illustrating a configuration example of a communication system 900 when a mobile terminal device that performs cooperative communication is not included.
  • one mobile terminal apparatus 151 is located near the cell center of the base station apparatus 100 and communicates with the base station apparatus 100 without performing cooperative communication.
  • the other mobile terminal apparatus 151 is located near the cell center of the base station apparatus 101, and communicates with the base station apparatus 101 without performing cooperative communication.
  • FIG. 3 is a schematic configuration diagram illustrating a configuration example of the communication system 900 when a mobile terminal device that does not perform cooperative communication is not included.
  • two mobile terminal apparatuses 150 are both located at the cell edges of the base station apparatus 100 and the base station apparatus 101, and perform cooperative communication with both base station apparatuses 100 and 101.
  • the communication devices (base station device and mobile terminal device) of the communication system 900 of the present embodiment can communicate. The same applies to the second and subsequent embodiments.
  • FIG. 4 is a schematic block diagram showing the configuration of the base station apparatus 100 according to the first embodiment of the present invention.
  • base station apparatus 100 includes encoding sections 241 to 24L, scrambling sections 251 to 25L, modulation sections 261 to 26L, layer mapping section 27, precoding section 28, resource element mapping sections 301 to 30T, and OFDM signal generation section 311.
  • wireless transmission units 321 to 32T wireless transmission units 321 to 32T, a reference signal generation unit 29, a wireless reception unit 21, a reception signal processing unit 22, and a feedback information processing unit 23.
  • L represents the number of codewords input to the encoding units 241 to 24L
  • T represents the number of radio transmission units 321 to 32T (the number of antenna ports and the number of transmission antennas).
  • the radio reception unit 21 receives signals transmitted from the mobile terminal devices 150 and 151 through the uplink.
  • the signals from the mobile terminal devices 150 and 151 received by the wireless reception unit 21 include feedback information and data signals.
  • the feedback information is information based on the signal reception state (signal amplitude or the like) of the reference symbol (reference signal). That is, the wireless reception unit 21 (first wireless reception unit) receives feedback information based on the signal reception state of the reference symbol.
  • the reception signal processing unit 22 performs reception processing for transmission processing performed for transmission by the mobile terminal devices 150 and 151 such as OFDM demodulation processing, demodulation processing, and decoding processing on the signal received by the wireless reception unit 21.
  • the feedback information is extracted from the received data signal and output to the feedback information processing unit 23.
  • the base station apparatus 100 receives a plurality of mobile terminal apparatuses that have been subjected to user multiplexing using SC-FDMA (Single Carrier-frequency Division Multiple Access) as an uplink (that is, signal transmission from the mobile terminal apparatus to the base station apparatus). Are distinguished from each other. Note that the base station apparatus 100 may perform user multiplexing using other multiple access schemes such as OFDMA, time division multiple access, and code division multiple access.
  • SC-FDMA Single Carrier-frequency Division Multiple Access
  • the base station apparatus 100 specifies resources (elements for signal transmission divided by time, frequency, code, spatial domain, etc.) for each mobile terminal apparatus to transmit feedback information, and the mobile terminal apparatus is specified. Send feedback information on the resource Thereby, the base station apparatus 100 distinguishes feedback information from each mobile terminal apparatus. Note that the base station apparatus 100 may distinguish the feedback information from each mobile terminal apparatus by another method, such as the mobile terminal apparatus adding a unique identification number for each mobile terminal apparatus to the feedback information. .
  • the feedback information processing unit 23 generates control signals for performing various adaptive controls on the data signals transmitted to the mobile terminal devices 150 and 151 based on the feedback information such as CQI, PMI, and RI.
  • the feedback information processing unit 23 outputs the generated control signals to the encoding units 241 to 24L, the modulation units 261 to 26L, the layer mapping unit 27, the precoding unit 28, and the resource element mapping units 301 to 30T.
  • the adaptive control performed by the feedback information processing unit 23 will be described.
  • the mobile terminal apparatuses 150 and 151 transmit recommended transmission format information (CQI, RI, and PMI) to the base station apparatus 100 as feedback information.
  • the feedback information is obtained by indexing a transmission format known to both the base station apparatus 100 and the mobile terminal apparatuses 150 and 151, and indicates a transmission scheme (transmission format) recommended by the mobile terminal apparatuses 150 and 151 by an index.
  • Recommended transmission format information The base station apparatus 100 performs transmission using the transmission method indicated by the recommended transmission format information.
  • the index indicating the coding rate and the modulation scheme is called CQI
  • the index showing the precoding matrix is called PMI
  • the index showing the number of layers (the number of spatial multiplexing, the number of ranks) Y is called RI.
  • the feedback information processing unit 23 controls the encoding units 241 to 24L and the modulation units 261 to 26L according to CQI, controls the precoding unit 28 according to PMI, and controls the layer mapping unit 27 according to RI. That is, the feedback information processing unit 23 controls the transmission method of transmission data based on the feedback information.
  • the feedback information processing unit 23 stores therein a lookup table in which CQI is associated with a coding rate and a modulation scheme, and the coding rate and modulation scheme corresponding to the input CQI are Is obtained from the lookup table.
  • the feedback information processing unit 23 controls the encoding units 241 to 24L to perform encoding at the acquired encoding rate, and controls the modulation units 261 to 26L to perform modulation using the acquired modulation scheme.
  • the feedback information processing unit 23 stores therein a lookup table in which the PMI and the precoding matrix are associated with each other, and acquires the precoding matrix corresponding to the input PMI from the lookup table.
  • the feedback information processing unit 23 controls the precoding unit 28 to perform precoding according to the acquired precoding matrix. Further, the feedback information processing unit 23 stores therein a lookup table in which RI and the number of layers Y are associated with each other, and acquires the number of layers Y corresponding to the input RI from the lookup table. The feedback information processing unit 23 controls the layer mapping unit 27 to perform mapping according to the acquired layer number Y. The feedback information processing unit 23 may control an upper layer (not shown) that generates a code word in accordance with RI.
  • the mobile terminal apparatus 150 may transmit feedback information regarding mapping to resources.
  • the feedback information processing unit 23 controls the resource element mapping units 301 to 30T to perform mapping corresponding to the transmitted feedback information.
  • SINR may be received as feedback information.
  • the feedback information processing unit 23 stores therein a lookup table in which SINR and code rate are associated with each other.
  • information indicating the channel condition (CSI; Channel State Information) is received as feedback information, and the precoding matrix, coding rate, modulation scheme, and number of layers Y that maximize the power received by the mobile terminal apparatus 150 are fed back.
  • the information processing unit 23 may determine the information.
  • a known method can be used as the determination method.
  • the feedback information processing unit 23 controls the precoding unit 28 to perform precoding based on the determined precoding matrix, and controls the code units 241 to 24L to perform encoding at the determined coding rate, thereby determining the determined modulation.
  • the modulation units 261 to 26L are controlled so as to perform modulation according to the method, and the layer mapping unit 27 is controlled to perform layer mapping with the determined number of layers Y.
  • the encoding units 241 to 24L are turbo codes or convolutional codes for a codeword (transmission data, information data signal) of a desired signal to be transmitted input from an upper layer processing unit (not shown) of the base station apparatus 100. Encoding is performed using an error correction code such as an LDPC (Low Density Parity Check) code, and the result is output to scramblers 251 to 25L.
  • the code units 241 to 24L receive codeword input. It should be noted that the number of code words received by the encoding units 241 to 24L may be one or more.
  • the encoding units 241 to 24L may receive an input as a codeword, which is a processing unit that performs retransmission control such as HARQ (Hybrid Automatic Repeat reQuest) or a processing unit that performs error correction coding.
  • the scramblers 251 to 25L generate different scramble codes for each base station, and perform scramble processing based on the scramble codes on the encoded signals from the encoders 241 to 24L.
  • Modulators 261 to 26L perform BPSK (Binary Phase Shift Keying) or QPSK (Quadrature Phase Shift Keying) or QAM (Quadrature Amplitude Modulation, orthogonal) on the scrambled signal. Modulation processing is performed using a modulation method such as amplitude modulation.
  • the layer mapping unit 27 maps the signals output from the modulation units 261 to 26L to a layer (rank) that performs spatial multiplexing such as MIMO (Multi-Input Multi-Output). When the number of codewords is 2 and the number of layers Y is 4, the layer mapping unit 27 converts the codewords into two parallel signals, thereby setting the number of layers Y to 4. Note that the layer mapping unit 27 may perform mapping using another conversion method.
  • the number of code words input to the layer mapping unit 27 may be the same as the number of code words L input to the encoding units 241 to 24L, and is not limited to two. Further, the number Y of layers to which the layer mapping unit 27 performs mapping changes according to a control signal from the feedback information processing unit 23.
  • the precoding unit 28 performs precoding processing on the signal output from the layer mapping unit 27 (controls the phase and amplitude of the signal), and converts it into a parallel signal having the number T of antenna ports (transmitting antennas).
  • the precoding unit 28 performs precoding processing according to a predetermined precoding matrix input from the feedback information processing unit 23.
  • the precoding unit 28 performs CDD (Cyclic Delay Delay Diversity), transmission diversity (SFBC (Spatial Frequency Block) Code), STBC (Spatial Time Block Block Code), TSTD (Time Switched Transmission Transmission Diversity) or FSTD (Frequency Switched Transmission).
  • the precoding process may be performed using another method such as a process using the. In this case, the feedback information processing unit 23 outputs control information corresponding to the precoding process.
  • the reference signal generation unit 29 generates a sequence of reference symbols known to each other (transmission side reference symbol sequence) between the base station and the mobile terminal, and outputs it to the resource element mapping units 301 to 30T.
  • the reference symbol sequence generated by the reference signal generation unit 29 is referred to as a reference symbol sequence when attention is paid to the sequence, and is referred to as a reference symbol when attention is paid to individual reference symbols. This is referred to as a reference signal.
  • the reference signal generation unit 29 generates a reference symbol from a random number based on the cell ID.
  • the reference signal generation unit 29 generates a reference symbol sequence based on an M (Maximum-length) sequence that is a pseudo noise sequence (pseudo random sequence, spreading code, PN (Pseudo Noise) sequence). Note that the sequence used by the reference signal generation unit 29 may be an arbitrary sequence (signal) as long as both the base station apparatus and the mobile terminal apparatus are known.
  • the reference signal generator 29 is a pseudo noise sequence other than M (Maximum-length) sequence such as Gold code, orthogonal Gold code, Barker code, orthogonal code sequence (Walsh code, OVSF (Orthogonal Variable Spreading Factor) code, Hadamard code, etc.)
  • the reference symbol sequence may be generated based on the above, or a sequence obtained by cyclically shifting these sequences or a sequence expanded cyclically may be used. Based on the orthogonal code sequence, the reference signal generation unit 29 generates a reference symbol sequence that is orthogonal to a reference symbol sequence of another base station apparatus.
  • the reference signal generation unit 29 may use a computer or the like to generate a sequence having excellent autocorrelation characteristics and cross-correlation characteristics, and use a reference symbol sequence based on this sequence. Details of the reference symbol sequence generated by the reference signal generation unit 29 will be described later.
  • the resource element mapping units 301 to 30T map the transmission data signal output from the precoding unit 28 and the reference symbol sequence output from the reference signal generation unit 29 to the resource element of each antenna port for each symbol.
  • mapping a reference symbol sequence to a resource element for each symbol is also simply referred to as mapping (assigning) a reference symbol sequence (to a resource element).
  • FIG. 5 is a conceptual diagram illustrating an example in which the resource element mapping units 301 to 30T map reference symbol sequences for four antenna ports.
  • one resource block (subframe) is composed of 12 subcarriers in the frequency direction and 14 OFDM symbols in the time direction.
  • Each subcarrier in one OFDM symbol is also called a resource element RE.
  • the front and rear OFDM symbols obtained by dividing the subframe into two in the time direction are also called slots.
  • the length of the OFDM symbol in the time direction is called OFDM symbol length LOFDS
  • the length of the slot in the time direction is called slot length LSL
  • the length of the subframe in the time direction is called subframe length LSF.
  • the length (bandwidth) of the subcarrier in the frequency direction is called a subcarrier interval WSC
  • the length of the resource block in the frequency direction is called a resource block width WRB.
  • Numerals attached to resource elements RE in the figure represent reference symbols transmitted from antenna ports 1 to 4, respectively.
  • no signal is assigned to the resource elements RE in the other antenna ports and zero is set so that the resource element mapping units 301 to 30T have the antennas.
  • Signals between ports are orthogonalized.
  • the number of OFDM symbols of the resource block to which the resource element mapping units 301 to 30T perform mapping may be variable. For example, when adding a long guard interval, the resource element mapping sections 301 to 30T perform mapping by setting the number of OFDM symbols in one slot to six.
  • the resource element mapping units 301 to 30T may change the number of resource blocks in the frequency direction according to the frequency bandwidth (system bandwidth) used by the communication system.
  • the resource element mapping units 301 to 30T can use 6 to 110 resource blocks, and can further increase the total system bandwidth to 110 or more by frequency aggregation.
  • one component carrier is composed of 100 physical resource blocks, and by setting five component carriers with a guard band between component carriers, the total system bandwidth is composed of 500 physical resource blocks, and resource
  • the element mapping units 301 to 30T may perform mapping for each resource block.
  • one component carrier has a bandwidth of 20 MHz, and the total system bandwidth can be 100 MHz with five component carriers with a guard band between the component carriers.
  • the resource element mapping units 301 to 30T may perform mapping for all resource blocks in the entire system bandwidth, or may perform mapping for some resource blocks. Further, mapping may be performed on some resource elements RE in the resource block.
  • Resource element mapping sections 301 to 30T assign reference symbols based on pseudo-noise sequences as reference symbols in at least one antenna port, and assign reference symbols generated from random numbers based on cell IDs as reference symbols in the remaining antenna ports. . Details will be described later. Further, different types of transmission data are mapped to resource elements other than the resource element to which the reference symbol is assigned.
  • the OFDM signal generators 311 to 31T perform frequency-time transform processing on the frequency domain signals output from the resource element mapping units 301 to 30T by inverse fast Fourier transform (IFFT), and thereby the time domain signals. Convert to Furthermore, the OFDM signal generators 311 to 31T add a guard interval (GI; Guard Interval; also referred to as CP) by cyclically expanding a part of each OFDM symbol converted into a time domain signal. .
  • GI Guard Interval
  • CP guard interval
  • Each of the wireless transmission units 321 to 32T includes one transmission antenna.
  • the radio transmission units 321 to 32T perform frequency conversion from the baseband to the radio frequency on the signal output from the OFDM signal generation unit, and transmit the signal from the transmission antenna.
  • the signals input from the OFDM signal generators 311 to 31T are signals indicating the transmission data mapped by the resource element mapping units 301 to 30T and the reference symbol sequence. That is, radio transmission sections 321 to 32T (first radio transmission sections) generate and transmit radio signals indicating transmission data and reference symbol sequences according to the mapping performed by mapping sections 301 to 30T.
  • the configuration and the function of each unit are the same as those of the base station apparatus 100. However, as described later, the reference symbol sequence generated by the reference signal generation unit 29 of the base station apparatus 101 or the position where the resource element mapping units 301 to 30T map the reference symbols is different from the base station apparatus 100.
  • FIG. 6 is a schematic block diagram illustrating a configuration of the mobile terminal device 150 in the present embodiment.
  • a mobile terminal apparatus 150 includes radio reception units 511 to 51R, OFDM signal demodulation units 521 to 52R, resource element demapping units 531 to 53R, a filter unit 55, a layer demapping unit 57, a deprecoding unit 56, and a demodulation.
  • the mobile terminal apparatus 150 includes R reception antennas, and one radio reception unit corresponds to one antenna.
  • the radio reception units 511 to 51R (second radio reception units) receive radio signals transmitted from the base station apparatus and passed through the transmission path (propagation path, channel), conversion processing from radio frequency to baseband signal, etc. I do.
  • the OFDM signal demodulation units 521 to 52R remove guard intervals, perform time frequency conversion processing by Fast Fourier Transform (FFT), etc., and convert the signals into frequency domain signals.
  • FFT Fast Fourier Transform
  • N T is the number of transmit antennas
  • N R is the number of receive antennas
  • the transmission signal S (k) is corresponding to each transmitting antenna
  • N (k) is the Noise corresponding to the receiving antenna
  • H (k) represents a frequency response corresponding to each receiving antenna and each transmitting antenna
  • T represents a transposed matrix.
  • Resource element demapping sections 531 to 53R demap (separate and extract) the data signal mapped by base station apparatuses 100 and 101 and the reference symbol sequence, feed the data signal to filter section 55, and feed back the reference symbol sequence to feedback information. It outputs to the production
  • the resource element demapping units 531 to 53R store therein mapping information performed by the base station apparatuses 100 and 101, and perform demapping based on this information.
  • the propagation path estimation unit 54 performs propagation path estimation by estimating amplitude and phase fluctuations (frequency response, transfer function) in each resource element based on the input reference symbols. For resource elements to which reference symbols are not mapped, propagation path estimation is performed by interpolating propagation path estimation values in the frequency direction and time direction based on the resource elements to which reference symbols are mapped. As an interpolation method, the propagation path estimation unit 54 uses linear interpolation. Note that other interpolation methods such as parabolic interpolation, polynomial interpolation, Lagrangian interpolation, spline interpolation, FFT interpolation, and minimum mean square error (Minimum Mean Square Error; MMSE) interpolation may be used. The propagation path estimation unit 54 performs propagation path estimation for each reception antenna with respect to each transmission antenna.
  • MMSE Minimum Mean Square Error
  • the filter unit 55 performs channel compensation on the data signal for each reception antenna output from the resource element demapping units 531 to 53R, using the channel estimation value output from the channel estimation unit 54, and transmits the transmission signal.
  • Estimate S (k) The filter unit 55 estimates the transmission signal S (k) based on the ZF (Zero Forcing) criterion using the weighting coefficient M ZF of Expression (2).
  • H ′ (k) represents an estimated frequency response in cooperative communication
  • H ′ H (k) represents a complex conjugate transpose matrix of H ′ (k)
  • ⁇ 1 represents an inverse matrix.
  • the filter unit 55 may estimate the transmission signal S (k) based on the MMSE criterion using the weighting factor M MMSE of Equation (3), or may use another criterion.
  • a reference signal for signal demodulation UE -A method of further mapping the reference signal for each layer as specific RS, user-specific reference signal, Demodulation RS
  • the feedback information is preferably generated based on the reference signal mapped for each transmission antenna port as described above.
  • H ′ (k), H ′ H (k) and ⁇ 1 are as described above. Furthermore, sigma '2 is noise power, the I NR represents a unit matrix of N R ⁇ N R.
  • the filter unit 55 calculates an estimated value S ′ (k) of the transmission signal S (k) using Expression (4).
  • M (k) represents a weighting coefficient (such as MZF or MMMSE ).
  • the deprecoding unit 56 performs processing for returning the precoding processing performed by the base station apparatuses 100 and 101 to the data signal detected by the filter unit 55. Note that precoding processing using CDD or transmission diversity does not require deprecoding processing on the receiving side. Therefore, when precoding processing using CDD or transmission diversity is performed in the base station apparatus, the deprecoding unit 56 does not perform processing for CDD or transmission diversity.
  • the layer demapping unit 57 demaps the signal for each layer to each codeword. Demodulating sections 581 to 58L demodulate the signal from layer demapping section 57 based on the modulation scheme used by base station apparatuses 100 and 101.
  • the descrambling units 591 to 59L perform descrambling processing on the signals from the demodulation units 581 to 58L based on the scramble code used by the base station apparatuses 100 and 101.
  • Decoding sections 601 to 60L perform error correction decoding processing on the signals from demodulation sections 581 to 58L based on the encoding method used by base station apparatuses 100 and 101, and perform upper layer processing of mobile terminal apparatus 150. Part (not shown).
  • the feedback information generation unit 61 generates feedback information based on the reference symbol sequence output from the resource element demapping units 531 to 53R.
  • the feedback information generation unit 61 measures the received signal power to interference plus noise power ratio (SINR) using the input reference symbol sequence to generate feedback information. Details will be described later. Note that the feedback information generation unit 61 measures the received signal power to interference power ratio (SIR), the received signal power to noise power ratio (SNR), the path loss, or the like to provide feedback information. May be generated.
  • the unit for generating the feedback information includes the frequency direction (for example, for each subcarrier, for each resource element, for each resource block, for each subband composed of a plurality of resource blocks), for example, for the time direction (for example, for each OFDM symbol, For each frame, each slot, each radio frame, etc.), spatial direction (for example, each antenna port, each transmission antenna, each reception antenna, etc.), and the like can be used.
  • the frequency direction for example, for each subcarrier, for each resource element, for each resource block, for each subband composed of a plurality of resource blocks
  • the time direction for example, for each OFDM symbol, For each frame, each slot, each radio frame, etc.
  • spatial direction for example, each antenna port, each transmission antenna, each reception antenna, etc.
  • the feedback information generation unit 61 of the mobile terminal apparatus 150 that performs cooperative communication performs despreading processing on the reference symbol sequence extracted from the transmission signal.
  • the feedback information generation unit 61 of the mobile terminal device 150 is also referred to as a second feedback information generation unit (second transmission path condition measurement unit).
  • the feedback information generation unit 61 of the mobile terminal device 151 that does not perform cooperative communication uses each reference symbol independently without despreading the reference symbol sequence. That is, feedback information generating section 61 of mobile terminal apparatus 151 measures the signal reception state (SINR) from the base station apparatus based on the reference symbols included in the reference symbol sequence, and generates feedback information according to the measured signal reception state. To do.
  • the feedback information generation unit 61 of the mobile terminal device 151 is also referred to as a first feedback information generation unit (first transmission path condition measurement unit). Details will be described later.
  • the despreading process is an autocorrelation between a reference symbol sequence extracted by the resource element demapping units 531 to 53R from a radio signal received by the mobile terminal device and a known reference symbol sequence used in transmission by the base station device. It means taking. By taking autocorrelation, it is possible to extract reference symbols from the desired base station apparatus while suppressing or reducing interference from other base station apparatuses. That is, the feedback information generation unit 61 despreads the reference symbol sequence extracted from the received radio signal based on the reference symbol sequence transmitted by the base station apparatus (takes autocorrelation between them), and the reference symbol after despreading Further, feedback information is generated based on the despread reference symbols extracted as described above.
  • the mobile terminal apparatus 150 can perform despreading processing by obtaining an autocorrelation value for an arbitrary reference symbol sequence (for example, a reference symbol sequence generated by a random number or the like).
  • an arbitrary reference symbol sequence for example, a reference symbol sequence generated by a random number or the like.
  • the unit for generating feedback information and the unit for performing despreading processing may be different.
  • the mobile terminal device 150 uses, as feedback information, precoding matrix information (PMI) used by the precoding units 28 of the base station devices 100 and 101, and coding processing and modulation performed by the coding units and modulation units of the base station devices 100 and 101.
  • PMI precoding matrix information
  • MCS Modulation and Code Scheme
  • RI Layer mapping unit of the base station apparatus
  • CSI CSI or the like
  • the transmission signal generation unit 62 performs encoding processing, modulation processing, OFDM signal generation processing, and the like to transmit (feedback) the feedback information output from the feedback information generation unit 61 to the base station apparatuses 100 and 101. Is generated.
  • the radio transmission unit 63 (second radio transmission unit) up-converts a transmission signal including feedback information generated by the transmission signal generation unit 62 to a radio frequency, and then transmits the radio signal to the base station apparatuses 100 and 101 through the uplink.
  • the configuration and functions of each unit are the same as those of the mobile terminal device 150. However, mobile terminal apparatus 151 is different from mobile terminal apparatus 150 in that it communicates only with base station apparatus 100 and feedback information generating section 61 does not despread the reference symbol sequence.
  • FIG. 7 is a flowchart illustrating a procedure in which the base station apparatus 100 generates and maps a reference symbol sequence.
  • the reference signal generation unit 29 generates a reference symbol sequence for each antenna port based on the sequence stored therein, and outputs the reference symbol sequence to the resource element mapping units 301 to 30T.
  • the resource element mapping units 301 to 30T map the reference symbol sequence input from the reference signal generation unit 29 and the transmission data signal input from the precoding unit 28 for each symbol according to the mapping information stored therein. And output to the OFDM signal generators 311 to 31T.
  • the base station apparatus 100 ends the reference symbol sequence generation and mapping process. Thereafter, the mapped signal is wirelessly transmitted via the OFDM signal generators 311 to 31T and the wireless transmitters 321 to 32T.
  • the procedure for generating and mapping the reference symbol sequence by the base station apparatus 101 is the same.
  • FIG. 8 is a flowchart showing a procedure in which the feedback information generation unit 61 of the mobile terminal device 150 generates feedback information.
  • Feedback information generation unit 61 receives reference symbol sequences from resource element demapping units 531 to 53R and starts generating feedback information.
  • the feedback information generation unit 61 performs despreading on the input reference symbol sequence, and based on the obtained reference symbol, information on the signal reception state from the base station apparatus 100 and the signal from the base station apparatus 101 And reception status information.
  • step S ⁇ b> 22 the feedback information generation unit 61 generates a PMI to be notified to each base station apparatus based on the signal reception state information from the base station apparatus 100 and the signal reception state information from the base station apparatus 101.
  • step S ⁇ b> 23 feedback information generation section 61 generates CQIs to be notified to each base station apparatus based on the signal reception state information from base station apparatus 100 and the signal reception state information from base station apparatus 101.
  • step S ⁇ b> 24 the feedback information generation unit 61 generates RI to be notified to each base station apparatus based on the signal reception state information from the base station apparatus 100 and the signal reception state information from the base station apparatus 101.
  • the feedback information generation unit 61 ends the feedback information generation process. Thereafter, the generated CQI, PMI, and RI are wirelessly transmitted as feedback information via the transmission signal generation unit 62 and the wireless transmission unit 63.
  • the procedure for the feedback information generating unit 61 of the mobile terminal device 151 to generate feedback information is the same.
  • the feedback information generation unit 61 does not perform despreading in step S21, but generates information on the signal reception state from the base station apparatus 100 using each of the input reference symbols as it is. In the following steps, the feedback information generation unit 61 generates only feedback information to be notified to the base station apparatus 100.
  • a signal reception state information a frequency response or a transfer function in a propagation path between the base station device and the mobile terminal device can be used. The order of generating feedback information is not limited to the above.
  • FIG. 9 is a flowchart illustrating a procedure in which the feedback information processing unit 23 of the base station apparatus 100 determines the coding rate of the data signal based on the feedback information.
  • the feedback information processing unit 23 receives the feedback information from the received signal processing unit and starts processing.
  • the feedback information processing unit 23 extracts feedback information (CQI, PMI, and RI) from the mobile terminal device 150 and feedback information from the mobile terminal device 151 from the signal input from the received signal processing unit 22.
  • the feedback information processing unit 23 refers to the lookup table stored therein, determines the coding rate based on the CQI from the mobile terminal devices 150 and 151, and notifies the coding units 241 to 24L.
  • the encoding units 241 to 24L perform encoding by changing the encoding rate to the notified encoding rate.
  • the feedback information processing unit 23 determines a modulation scheme change based on the CQI from the mobile terminal apparatuses 150 and 151 with reference to a lookup table stored therein, and notifies the modulation units 261 to 26L.
  • the modulation units 261 to 26L perform modulation according to the notified modulation method.
  • step S ⁇ b> 34 the feedback information processing unit 23 determines a change in the number of layers based on the CQI from the mobile terminal devices 150 and 151 with reference to a lookup table stored therein, and notifies the layer mapping unit 27 of the change.
  • the layer mapping unit 27 performs mapping according to the notified number of layers.
  • the feedback information processing unit 23 determines a precoding matrix change based on the PMI from the mobile terminal devices 150 and 151 with reference to a lookup table stored therein, and notifies the precoding unit 28 of the change.
  • the precoding unit 28 performs precoding according to the notified precoding matrix.
  • the feedback information processing unit 23 ends the determination process such as the coding rate.
  • the procedure in which the feedback information processing unit 23 of the base station apparatus 101 determines the coding rate and the like is the same. However, in the case of the base station apparatus 101, the feedback information processing unit 23 extracts only feedback information from the mobile terminal apparatus 150 in step S31, and encodes based on the feedback information from the mobile terminal apparatus 150 in the following steps as well. Determine rates, etc.
  • FIG. 10A is a conceptual diagram illustrating an example of a reference symbol sequence used by base station apparatus 100 for antenna port 1.
  • the reference symbol sequences a to h in the figure are generated based on an M sequence that is a pseudo-noise sequence of 8 chips (bits).
  • the series in the figure is a series based on the M series.
  • the M-sequence has excellent autocorrelation characteristics (that is, when despreading is performed, a sharp (high) correlation value (peak value) is obtained when the sequence is synchronized, and low when the sequence is out of synchronization.
  • the 8-chip sequence a to h provides a sharp correlation value at the position a, that is, a sharp correlation value is obtained when the correlation is obtained without shifting the sequence.
  • the reference symbol sequence generated by the reference signal generation unit 29 is not limited to the M sequence, and reference symbols of other sequences may be generated.
  • FIG. 10B is a conceptual diagram illustrating an example in which the base station apparatus 100 maps the reference symbol sequence in FIG. 10A.
  • FIG. 10C is a conceptual diagram illustrating an example in which the base station device 101 maps the reference symbol sequence obtained by cyclically shifting the reference symbol sequence in FIG. 10A to the same resource element as the base station device 100.
  • 10B and 10C among the reference symbol sequences shown in FIG. 5, the reference symbol sequences for antenna port 1 are indicated by a to h, and the reference symbol sequences for antenna ports 2 to 4 are indicated by shading.
  • the reference symbol sequence used by base station apparatus 101 is a cyclic shift of the series used by base station apparatus 100 in FIG. 10B. By shifting cyclically, the position where a sharp correlation value is obtained can be varied.
  • Base station apparatus 100 and base station apparatus 101 map reference symbol sequences to the same resource elements for each symbol.
  • the reference signal generation unit 29 of the base station apparatus 100 generates a signal based on a 0-chip shifted pseudo noise sequence, that is, a sequence that is not shifted, as a reference symbol sequence for the antenna port 1.
  • Resource element mapping sections 301 to 30T of base station apparatus 100 map the generated reference symbol sequence as shown in FIG. 10B.
  • the reference signal generation unit 29 of the base station 101 generates a signal based on a one-chip shifted pseudo noise sequence as a reference symbol sequence for the antenna port 1. That is, the reference symbol sequence generated by the reference signal generation unit 29 is a cyclic shift of the reference symbol sequence of another base station apparatus.
  • Resource element mapping sections 301 to 30T of base station 101 map generated reference symbol sequences as shown in FIG. 10C.
  • mobile terminal apparatus 150 that performs cooperative communication between base station 100 and base station 101 estimates feedback information for each base station apparatus.
  • estimation is performed using reference symbols independently from each of base station apparatuses 100 and 101 (that is, without performing despreading), transmission signals between adjacent cells interfere with each other, and mobile terminal apparatus 150 in particular
  • the mobile terminal apparatus 150 estimates feedback information in a situation where inter-cell interference is large.
  • the inter-cell interference is suppressed or reduced.
  • the feedback information generation unit 61 of the mobile terminal apparatus 150 that simultaneously receives transmission signals from the base station apparatus 100 and the base station apparatus 101 and performs cooperative communication suppresses interference from neighboring cells by performing despreading or The optimum feedback information for performing cooperative communication can be estimated.
  • the base station apparatus 100 and the base station apparatus 101 transmit the same data signal in synchronization (for example, the base station apparatus 100 and the base station apparatus 101 exchange synchronization information with priority or wirelessly,
  • the base station apparatuses 100 and 101 transmit different reference symbols using the same resource element, so that the reference symbols are transmitted.
  • the mobile terminal apparatus 150 can generate and transmit feedback information for each base station apparatus without an increase in overhead due to the above.
  • the mobile terminal apparatus 150 determines, for each base station apparatus, a precoding matrix (specifically, a PMI) corresponding to a signal reception state from each base station apparatus (each of the base station apparatuses 100 and 101), or individually.
  • the base station apparatus (each of the base station apparatuses 100 and 101) can determine and transmit a common precoding matrix (specifically, PMI) between the base station apparatuses in accordance with the signal reception state.
  • the mobile terminal apparatus 150 can generate feedback information by extracting reference symbols for each base station apparatus by correlating the reference symbol sequences of the base station apparatuses 100 and 101 with the received reference symbol series. it can.
  • a pseudo-noise sequence having excellent autocorrelation characteristics as a sequence that is a basis for generating a reference symbol sequence
  • the effect of suppressing or reducing interference can be obtained more greatly.
  • the effect of suppressing or reducing interference can be further increased by using an M sequence having excellent autocorrelation characteristics.
  • the mobile terminal apparatus 151 that does not perform the cooperative communication independently uses the reference symbol sequence without performing despreading in the feedback information generation unit 61 even if the reference symbol sequence is based on the pseudo-noise sequence.
  • the base station apparatus 101 does not need to newly notify the mobile terminal apparatus of control information or the like.
  • a communication system in which mobile terminal apparatuses 150 that perform cooperative communication and mobile terminal apparatuses that do not perform cooperative communication can be realized without increasing the ratio (overhead) of reference symbols to the entire resource.
  • the effect of suppressing or reducing interference is increased by orthogonalizing reference symbol sequences based on pseudo noise sequences between adjacent cells. Therefore, the sequences used by the base station device 100 and the base station device 101 are assigned by a control station located above these base station devices so that their reference symbol sequences are orthogonal to each other. It should be noted that a method of cooperating with each other through a line such as X2 or radio where the base stations communicate control signals or a method generated by each base station device using a parameter such as a cell ID is used. It may be. Base station apparatuses 100 and 101 notify mobile terminal apparatus 150 of the used pseudo-noise sequence, the used reference symbol, the number of shifts, the index (number) of a predefined reference symbol sequence, and the like.
  • the mobile terminal apparatus 150 may specify the pseudo noise sequence and the number of shifts using parameters such as the cell ID notified from the base station apparatuses 100 and 101. Even when the mobile terminal device 150 performs cooperative communication, the base station device that transmits the control information signal to the mobile terminal device 150 and the base station device that the mobile terminal device 150 transmits feedback information
  • the base station apparatus is not limited to one of the base station apparatuses, and may be any one of base station apparatuses performing cooperative communication such as an anchor cell. Even when the mobile terminal device 150 performs cooperative communication, the base station device that transmits the control information signal to the mobile terminal device 150 and the base station device that transmits the feedback information to the mobile terminal device 150 perform cooperative communication. All the base station apparatuses currently performing may be sufficient.
  • FIG. 11A is a conceptual diagram illustrating an example in which the base station apparatus 100 maps reference symbol sequences in the same manner as in FIG. 10B.
  • FIG. 11B is a conceptual diagram illustrating an example in which the base station apparatus 101 maps the reference symbol sequence to a resource element shifted by one subcarrier in the frequency direction from the position illustrated in FIG. 10C.
  • 11A and 11B, as in FIGS. 10B and 10C the reference symbol sequences of antenna port 1 are indicated by a to h, and the reference symbol sequences of antenna ports 2 to 4 are indicated by shading.
  • the base station apparatus 100 and the base station apparatus 101 perform mapping in the same manner as described with reference to FIGS. 10B and 10C. However, in FIG.
  • the mapping performed by base station apparatus 101 is shifted in the frequency direction by one subcarrier higher in the frequency direction (upward) than in the case of FIG. 10C. That is, resource element mapping sections 301 to 30T of base station apparatuses 100 and 101 map reference symbols to resource elements different from each other between adjacent base station apparatuses.
  • reference symbol sequence of the base station apparatus 100 received by the mobile terminal apparatus and the arrangement of the data signals of the base station apparatus 101 are mapped to the same resource element.
  • reference symbol sequence from base station apparatus 100 and the symbol series (data signal sequence) from base station apparatus 101 are not orthogonal to each other, reference signal generation unit 29 uses an M sequence having sharp autocorrelation characteristics. By generating a reference symbol sequence and performing despreading by the mobile terminal apparatus 150, interference from other cells can be greatly reduced, and optimal feedback information for performing cooperative communication can be estimated.
  • the sequence used by the reference signal generation unit 29 may be a sequence having excellent autocorrelation characteristics, and is not limited to the M sequence.
  • the reference symbol sequence based on the pseudo noise sequence is used for all reference symbols of all antenna ports.
  • the resource element mapping units 301 to 30T use the pseudo noise sequence only for a part of them.
  • the reference symbol sequence that has been stored may be mapped.
  • a reference symbol sequence based on a pseudo noise sequence may be assigned to a reference symbol in one antenna port, and a reference symbol generated from a random number based on a cell ID may be assigned to reference symbols in the remaining antenna ports. .
  • the number of antenna ports of the base station apparatuses 100 and 101 is four has been described above, the number of antenna ports is not limited to four and may be one or more antenna ports.
  • 11A and 11B a case has been described in which a resource element that maps a reference symbol sequence is shifted between adjacent cells based on a parameter such as a cell ID.
  • cooperative communication such as between all cells or Active CoMP set is performed.
  • the resource elements to which reference symbols are mapped in advance may be determined among the plurality of cells that perform the above, and the resource elements determined by the resource element mapping units 301 to 30T may be stored.
  • a base station such as RRE (Remote Radio Equipment), RRH (Remote Radio Head), or an independent antenna is controlled through a wire such as an optical fiber as a unit for orthogonalizing reference symbol sequences based on a pseudo noise sequence between cells.
  • a unit, a unit controlled by a base station such as a relay, or a unit configured by a plurality of base stations performing cooperative communication such as Active CoMP set, or a unit of a resource element that maps a reference symbol is used. It may be.
  • the base station apparatus 100 determines the type of pseudo-noise sequence, the position where the peak of the autocorrelation characteristic is obtained, etc. based on the identification information and control information notified to the mobile terminal apparatus 150, and the base station apparatus 100 determines the mobile terminal apparatus.
  • 150 may be notified of identification information and control information at the same time by notifying 150 the type of pseudo noise sequence, the position where the peak of the autocorrelation characteristic is obtained, and the like.
  • the sequence length of the pseudo-noise sequence used by the base station apparatus may be different from the sequence length that the mobile terminal apparatus performs despreading processing on.
  • the mobile terminal apparatus 150 performs the despreading process on the reference symbol sequence in order to generate feedback information. However, the mobile terminal apparatus 150 performs the despreading process when estimating the propagation path for demodulating the information data signal. May be.
  • cooperative communication may be performed between a plurality of base station devices and at least one mobile terminal device.
  • Collaborative communication between physically independent base station apparatuses, or cooperative communication between sectors in one base station apparatus having a sector configuration, or a transmission apparatus (RRE) connected to the base station apparatus by wire such as an optical fiber Or RRH), or a cooperative communication between a base station apparatus and a transmission apparatus (such as a relay station or a repeater station) connected wirelessly using relay technology.
  • RRE transmission apparatus
  • a base station apparatus and a transmission apparatus such as a relay station or a repeater station
  • a mobile terminal apparatus that performs cooperative communication with a plurality of base station apparatuses performs despreading processing, and performs communication with one base station apparatus without performing cooperative communication.
  • a mobile terminal that performs cooperative communication may perform despreading processing
  • a mobile terminal that performs MIMO (Multi Input Multi Output) communication may generate feedback information without performing despreading processing.
  • Feedback information generating section 29 of mobile terminal apparatus 150 that receives transmission signals from a plurality of base station apparatuses 100 and 101 simultaneously and performs cooperative communication performs despreading on reference symbol sequences from the respective base station apparatuses.
  • the signal power (signal amplitude) obtained from each base station apparatus is measured while suppressing interference from adjacent cells.
  • the feedback information generation unit 29 estimates SINR from the signal power (signal amplitude) obtained from each base station apparatus, acquires CQI, PMI, and RI corresponding to the SINR estimated from the lookup table, and feeds them back to the feedback information. And That is, the feedback information is information based on the signal reception state (signal amplitude) of the reference symbol.
  • SINR total SINR
  • the mobile terminal apparatus 151 that does not perform cooperative communication may also despread the reference symbol sequence.
  • the mobile terminal device 151 receives the reference symbol sequence transmitted from the communicating base station device (own base station, own cell, serving cell) 100, and correlates the reference symbol sequence transmitted by the base station device.
  • the signal power (signal amplitude) obtained by this base station can be measured while suppressing interference from adjacent cells.
  • each reference symbol sequence chip includes an interference component from an adjacent base station
  • the reference symbol amplitude and received signal from the own base station are referred to by referring to the resource element to which the reference symbol is mapped.
  • average interference signal power can be obtained, and optimum feedback information (CQI, PMI, etc. based on SINR or SINR) can be estimated.
  • Mobile terminal apparatus 150 may perform despreading processing beyond the sequence length used by base station apparatus 100, or may perform despreading processing for a length less than the sequence length.
  • Base station apparatus 100 or 101 notifies mobile terminal apparatus 150 of a set of cells on which despreading processing is to be performed.
  • the cell set information includes the number of cells, each cell ID, and the pseudo noise sequence of each cell. Note that the pseudo-noise sequence of a cell may be determined by a cell ID or the like.
  • the base station apparatus 100 or 101 receives a measurement report (Measurement Report) from the mobile terminal apparatus 150, and determines a set of cells in which cooperative communication is to be performed using the measurement report.
  • the mobile terminal apparatus 150 When the mobile terminal apparatus 150 is notified of the set of cells to be despread, the mobile terminal apparatus 150 performs despread processing on the reference symbol sequence transmitted from each cell. As described above, feedback information generation section 61 performs despreading on the received reference symbol sequence to obtain a reference symbol in which interference from other base stations is suppressed or reduced. The feedback information generation unit 61 measures signal power (signal amplitude) from a reference symbol whose interference is suppressed or reduced. The feedback information generation unit 61 estimates SINR from the measured signal power, acquires CQI, PMI, and RI corresponding to the SINR estimated from the lookup table, and uses these as feedback information.
  • the feedback information generation unit 61 stores therein a lookup table in which SINR and CQI satisfying required quality are associated with each other in advance.
  • the feedback information generation unit 61 uses the SINR estimated as described above to obtain a CQI by referring to a lookup table.
  • the feedback information generation unit 61 stores a lookup table in advance, refers to the lookup table using SINR, and acquires a precoding matrix that maximizes received power.
  • the feedback information generation unit 61 stores a lookup table in advance, and acquires the RI by referring to the lookup table using SINR.
  • the feedback information generation unit 61 may generate CSI as feedback information.
  • CSI in the receiving antenna port for each transmitting antenna port is generated from the result of performing the despreading process.
  • the feedback information generation unit 61 may compress the feedback information based on the CSI to reduce the amount of feedback information. A difference between transmission path conditions continuous in the time direction or the frequency direction may be used as feedback information. Further, the feedback information may be generated for each subband.
  • the following two methods are conceivable as a method of measuring the channel state from which the feedback information generating unit 61 generates feedback information.
  • the first method is a method for obtaining CQI and PMI based on total SINR or total SINR.
  • the feedback information generation unit 61 combines reference symbols of each cell obtained by performing the despreading process, measures a channel state based on one combined reference symbol, and feedback information based on the measured channel state Is generated.
  • the second method is a method of obtaining CQI and PMI based on SINR in each base station and SINR in each base station.
  • the feedback information generation unit 61 measures the channel state for each reference symbol of each cell obtained by performing the despreading process, and generates feedback information for necessary cells based on the measured channel state.
  • the feedback information generation unit 61 generates feedback information by the first method. Note that feedback information may be generated by the second method, or both the first method and the second method may be provided, and feedback may be performed by a method designated by the base station.
  • the resource element mapping units 301 to 30T map one series of reference symbol sequences for each resource block unit.
  • the communication system in the present embodiment includes base station apparatuses 100 and 101 and mobile terminal apparatuses 150 and 151 similar to those in the communication system in the first embodiment, but 100 and 101 are antennas included in the first embodiment. In addition to ports 1 to 4, antenna ports 5 to 8 are further included.
  • the mapping method of the resource element mapping unit is different from that of the first embodiment. Below, it demonstrates centering on a different part from 1st Embodiment.
  • FIG. 12A shows an example where base station apparatus 100 maps reference symbol sequences of antenna ports 5 to 8 to resource elements.
  • FIG. 12B shows another example in which the base station apparatus 100 maps the reference symbol sequences of the antenna ports 5 to 8 to resource elements.
  • Numbers 5 to 8 attached to resource elements in FIGS. 12A and 12B indicate reference symbol sequences of antenna ports 5 to 8, respectively.
  • the antenna ports are orthogonalized by assigning no signal to the resource elements in other antenna ports and setting them to zero (null).
  • antenna ports 1 to 4 are reference symbols generated based on random numbers using cell IDs, and these reference symbols are shown in shades in FIGS. 12A and 12B.
  • Base station apparatus 100 assigns reference symbol sequences of antenna ports 5 to 8 as shown in FIG. 12A. Note that base station apparatus 100 may allocate reference symbol sequences of antenna ports 5 to 8 as shown in FIG. 12B, or may perform other allocations.
  • FIG. 13A is a conceptual diagram illustrating an example of a 4-chip reference symbol sequence allocated to antenna port 5 among four newly added antenna ports illustrated in FIG. 12A by base station apparatus 100.
  • This reference symbol sequence is a reference symbol sequence based on a pseudo noise sequence.
  • FIG. 13B is a conceptual diagram illustrating an example in which the base station apparatus 100 maps the reference symbol sequence in FIG. 13A.
  • FIG. 13C is a conceptual diagram illustrating an example in which the base station device 101 maps the reference symbol sequence obtained by cyclically shifting the reference symbol sequence in FIG. 13A to the same resource element as the base station device 100. In FIG. 13B and FIG. 13C, among the reference symbol sequences shown in FIG.
  • the reference symbol sequences for antenna port 5 are indicated by a to d, and the reference symbols for antenna ports 1 to 4 are indicated by shading.
  • the reference signal generation unit 29 uses a sequence having excellent autocorrelation characteristics such as an M sequence as a pseudo noise sequence.
  • a sharp peak is obtained at the position a.
  • Base station apparatus 100 and base station apparatus 101 map the reference symbol sequence at the same position of the resource element.
  • base station apparatus 101 uses, as a reference symbol series, a series of base station apparatus 100 that is cyclically shifted by one chip.
  • the reference signal generation unit 29 of the base station apparatus 100 generates a reference symbol sequence based on a pseudo noise sequence shifted (ie, not shifted) by 0 chips as a reference symbol sequence for the antenna port 5.
  • the resource element mapping unit of base station apparatus 100 maps the generated reference symbol sequence as shown in FIG. 13B.
  • the reference signal generation unit 29 of the base station apparatus 101 generates a reference symbol sequence based on a pseudo noise sequence shifted by one chip as a reference symbol sequence for the antenna port 5.
  • the resource element mapping unit of the base station 2 maps the generated reference symbol sequence as shown in FIG. 13C.
  • the base station device 100 maps the reference symbol sequence as shown in FIG. 13B, and the base station device 101 maps the reference symbol sequence as shown in FIG.
  • the mobile terminal apparatus 150 that simultaneously receives transmission signals from the base station 100 and the base station 101 and performs cooperative communication can suppress interference from adjacent cells by performing despreading, and perform cooperative communication. It is possible to estimate the optimum feedback information for performing. Also, the mobile terminal device 151 that does not perform cooperative communication increases new processing by using each chip independently without performing despreading processing, even if the reference symbol sequence is based on a pseudo-noise sequence. And optimal feedback information can be estimated.
  • FIG. 14A is a conceptual diagram illustrating an example in which the base station apparatus 100 maps reference symbol sequences in the same manner as in FIG. 13B.
  • FIG. 14B is a conceptual diagram illustrating an example in which the base station apparatus 101 maps the reference symbol sequence to resource elements shifted by one subcarrier in the frequency direction from the position illustrated in FIG. 13C. 14A and 14B, as in FIGS. 13B and 13C, the reference symbol series of antenna port 5 is indicated by a to d, and the reference symbols of antenna ports 1 to 4 are indicated by shading.
  • FIG. 13B and FIG. 13C the case where the resource elements for mapping reference symbols (sequences) in the base station apparatus 100 and the base station apparatus 101 are the same has been described, but as shown in FIG. 14A and FIG.
  • the same effect can be obtained even when resource elements that map reference symbols in 100 and the base station 101 shift according to parameters such as a cell ID. 14A and 14B, the base station apparatus 100 and the base station apparatus 101 perform mapping in the same manner as described with reference to FIGS. 13B and 13C.
  • FIG. 14B the mapping performed by the base station apparatus 101 is shifted in the frequency direction (upward) by one subcarrier in the frequency direction compared to the case of FIG. 13C. 14A and 14B, as described in FIGS.
  • the reference symbol sequence received from the base station device 100 and the symbol sequence received from the base station device 101 received by the mobile terminal device are orthogonal to each other. Although there is no M-sequence with sharp autocorrelation characteristics and the mobile terminal apparatus 150 performs despreading, it is possible to significantly reduce other cell interference with each other and estimate optimum feedback information for cooperative communication can do.
  • the reference symbol sequence based on the pseudo noise sequence is used for all the reference symbols of all the antenna ports has been described above, only a part of them may be used. For example, a reference symbol sequence based on a pseudo noise sequence may be assigned to a reference symbol in one antenna port, and a reference symbol generated from a random number based on a cell ID may be assigned to reference symbols in the remaining antenna ports. .
  • the number of antenna ports to be newly added is not limited to four and may be one or more antenna ports. .
  • four antenna ports are further added to the four antenna ports 1 to 4.
  • the present invention is not limited to this, and one or more antenna ports are provided for one or more antenna ports. Any port may be added. For example, six new antenna ports may be added to the two antenna ports 1 and 2. Alternatively, eight antenna ports may be newly added.
  • the resource element that maps the reference symbol sequence is shifted between adjacent cells based on a parameter such as a cell ID. However, all the cells or a plurality of cooperative communication such as Active CoMP set are performed. Resource elements for mapping reference symbol sequences may be determined in advance between cells.
  • the resource element mapping units 301 to 30T map one sequence of reference symbol sequences in one resource block, and perform this for each resource block.
  • the communication system in the present embodiment includes base station apparatuses 100 and 101 and mobile terminal apparatuses 150 and 151 similar to the communication system in the first embodiment, but the mapping method of the resource element mapping unit is different. Below, it demonstrates centering on a different part from 1st Embodiment.
  • Base station apparatuses 100 and 101 of the present embodiment further include antenna ports 5 to 8 in addition to antenna ports 1 to 4 included in the first embodiment.
  • FIG. 15A shows a 4-symbol reference symbol sequence assigned to antenna port 5 among four newly added antenna ports.
  • This reference symbol sequence is a conceptual diagram showing an example of a reference symbol sequence based on a pseudo noise sequence.
  • FIG. 15B is a conceptual diagram illustrating an example in which the base station apparatus 100 maps a reference symbol sequence.
  • 15C the base station apparatus 101 maps the reference symbols of the antenna ports 1 to 4 while shifting the mapping of the base station apparatus 100 in the frequency direction, and the reference symbol sequence of the antenna port 5 is the base station apparatus.
  • It is a conceptual diagram which shows the example mapped to the resource element of the same position as 100 mapping.
  • the reference symbol series of antenna port 5 is indicated by a to d, and the reference symbols of antenna ports 1 to 4 are indicated by shading.
  • the reference symbol sequence of antenna port 5 is shown, and the reference symbol sequences of antenna ports 6 to 8 are not shown.
  • the reference signal generation unit 29 uses a sequence having excellent autocorrelation characteristics such as an M sequence as a pseudo noise sequence. In the 4-chip series a to d, a sharp peak is obtained at the position a.
  • Base station apparatus 100 and base station apparatus 101 map the reference symbol sequence to the same position of the resource element. Also, base station apparatus 101 uses a series of base station apparatus 100 that is cyclically shifted by one chip as a reference symbol series.
  • the reference signal generation unit 29 of the base station apparatus 100 generates a reference symbol sequence based on a 0-chip shifted pseudo noise sequence as a reference symbol sequence for the antenna port 5.
  • the resource element mapping unit of base station apparatus 100 maps the generated reference symbol sequence as shown in FIG. 15B.
  • the reference signal generation unit 29 of the base station apparatus 101 generates a reference symbol sequence based on a one-chip shifted pseudo noise sequence as a reference symbol sequence for the antenna port 5.
  • the resource element mapping unit of the base station 2 maps the generated reference symbol sequence as shown in FIG. 15C.
  • the reference symbol sequence transmitted by the base station apparatus 100 and the reference symbol sequence transmitted by the base station apparatus 101 are different from each other in the sequence peak position and orthogonal to each other. ing.
  • the mobile terminal apparatus 150 that simultaneously receives transmission signals from the base station 100 and the base station 101 and performs cooperative communication can suppress interference from adjacent cells by performing despreading, and perform cooperative communication. It is possible to estimate the optimum feedback information for performing.
  • the mobile terminal device 151 that does not perform cooperative communication increases new processing by using each chip independently without performing despreading processing, even if the reference symbol sequence is based on a pseudo-noise sequence. And optimal feedback information can be estimated.
  • the reference symbol sequence based on the pseudo noise sequence may be used for all the reference symbols of all the antenna ports, only a part of them may be used.
  • a reference symbol sequence based on a pseudo noise sequence may be assigned to a reference symbol in one antenna port, and a reference symbol generated from a random number based on a cell ID may be assigned to reference symbols in the remaining antenna ports. .
  • the number of antenna ports to be newly added is four in the base station apparatuses 100 and 101 has been described above, the number of antenna ports to be added is not limited to four and may be one or more antenna ports. .
  • the case where there are four antenna ports 1 to 4 reference symbols has been described.
  • the case where the reference symbol series is arranged in all resource blocks has been described above, it may be arranged only in some resource blocks.
  • four antenna ports are further added to the four antenna ports 1 to 4.
  • the present invention is not limited to this, and one or more antenna ports are provided for one or more antenna ports. Any port may be added. For example, six antenna ports may be newly added to the two antenna ports 1 and 2. Note that the method described in this embodiment and the method described in the second embodiment may be used in combination.
  • FIGS. 16A to 16D are conceptual diagrams illustrating an example in which the base station apparatus 100 maps reference symbol sequences of different antenna ports for each subframe. Specifically, in FIG. 16A to FIG. 16D, the base station apparatus 100 performs the nth subframe SF (n), the (n + 1) th subframe SF (n + 1), and the (n + 2) th subframe SF (n + 2), respectively. An example in which the reference symbol sequences of antenna port 5 to antenna port 8 are mapped to the (n + 3) th subframe SF (n + 3) is shown. In FIG. 16A to FIG.
  • the communication system in the present embodiment includes base station apparatuses 100 and 101 and mobile terminal apparatuses 150 and 151 similar to the communication system in the first embodiment, but the mapping method of the resource element mapping unit is different. Below, it demonstrates centering on a different part from 1st Embodiment.
  • Base station apparatuses 100 and 101 of the present embodiment further include antenna ports 5 to 8 in addition to antenna ports 1 to 4 included in the first embodiment.
  • the resource element mapping units 301 to 30T map one sequence of reference symbol sequences in one resource block, and perform this for each resource block.
  • the reference signal generation unit 29 generates a 4-chip reference symbol sequence to be assigned to the newly added antenna ports 5 to 8 based on the pseudo noise sequence, and the resource element mapping units 301 to 30T respectively generate the nth reference symbol sequences.
  • the reference signal generation unit 29 uses a sequence having excellent autocorrelation characteristics such as an M sequence as a pseudo noise sequence.
  • base station apparatus 101 uses a series of base station apparatus 100 that is cyclically shifted by one chip as a reference symbol series. Further, the resource element that maps the reference symbol sequence may be shifted between adjacent cells based on the cell ID or the like.
  • the reference symbol sequence transmitted by the base station apparatus 100 and the reference symbol sequence transmitted by the base station apparatus 101 are different from each other in the sequence peak position and orthogonal to each other. ing.
  • the mobile terminal apparatus 150 that simultaneously receives transmission signals from the base station 100 and the base station 101 and performs cooperative communication can suppress interference from adjacent cells by performing despreading, and perform cooperative communication. It is possible to estimate the optimum feedback information for performing.
  • the mobile terminal device 151 that does not perform cooperative communication increases new processing by using each chip independently without performing despreading processing, even if the reference symbol sequence is based on a pseudo-noise sequence. And optimal feedback information can be estimated.
  • the reference symbol sequence based on the pseudo noise sequence is used for all reference symbols of all newly added antenna ports. However, only a part of them may be used. For example, a reference symbol sequence based on a pseudo noise sequence may be assigned to a reference symbol in one antenna port, and a reference symbol generated from a random number based on a cell ID may be assigned to reference symbols in the remaining antenna ports. .
  • the reference symbol sequence based on the pseudo noise sequence is used for all the resource elements that map the reference symbols of the respective antenna ports has been described above, the reference symbols based on the pseudo noise sequence are only part of them. A series may be used.
  • the number of antenna ports to be newly added is four in the base station apparatuses 100 and 101 has been described above, the number of antenna ports to be added is not limited to four and may be one or more antenna ports. . Although the case where there are reference symbols for the antenna ports 1 to 4 has been described above, these may not be necessary. In addition, although the case where the reference symbol series is arranged in all the resource blocks has been described above, the reference symbol series may be arranged in only some resource blocks. In the above description, four antenna ports are further added to the four antenna ports 1 to 4. However, the present invention is not limited to this, and one or more antenna ports are provided for one or more antenna ports. Any port may be added. For example, six new antenna ports may be added to the two antenna ports 1 and 2. Alternatively, eight antenna ports may be newly added. Note that the method described in this embodiment may be applied in combination with the method described in the second to third embodiments.
  • FIGS. 17A to 17D are conceptual diagrams illustrating examples in which the base station apparatus 100 maps reference symbol sequences of different antenna ports for each resource block.
  • the base station apparatus 100 has the m-th resource block RB (m), the (m + 1) -th resource block RB (m + 1), the (m + 2) -th resource block RB (m + 2), An example in which the reference symbol sequences of antenna port 5 to antenna port 8 are mapped to the (m + 3) th resource block RB (m + 3) is shown.
  • reference symbol sequences of antenna ports 5 to 8 are indicated by 5 to 8, respectively, and reference symbols of antenna ports 1 to 4 are indicated by shading.
  • the communication system in the present embodiment includes base station apparatuses 100 and 101 and mobile terminal apparatuses 150 and 151 similar to the communication system in the first embodiment, but the mapping method of the resource element mapping unit is different. Below, it demonstrates centering on a different part from 1st Embodiment.
  • Base station apparatuses 100 and 101 of the present embodiment further include antenna ports 5 to 8 in addition to antenna ports 1 to 4 included in the first embodiment.
  • the resource element mapping units 301 to 30T map one sequence of reference symbol sequences in one resource block, and perform this for each resource block.
  • one of the reference symbol sequences of antenna ports 5 to 8 is arranged in one subframe, and the antenna ports are periodically arranged in the frequency direction (for each resource block).
  • the reference signal generator 29 generates a 4-chip reference symbol sequence to be assigned to the newly added antenna ports 5 to 8 based on the pseudo noise sequence, and the resource element mapping units 301 to 30T respectively generate the mth reference symbol sequences.
  • the reference signal generation unit 29 uses a sequence having excellent autocorrelation characteristics such as an M sequence as a pseudo noise sequence.
  • base station apparatus 101 uses a series of base station apparatus 100 that is cyclically shifted by one chip as a reference symbol series. Further, the resource element that maps the reference symbol may be shifted between adjacent cells based on the cell ID or the like. By mapping the reference symbol sequence as shown in FIGS.
  • the reference symbol sequence transmitted by the base station apparatus 100 and the reference symbol sequence transmitted by the base station apparatus 101 are different from each other in the sequence peak positions and orthogonal to each other. ing.
  • the mobile terminal apparatus 150 that simultaneously receives transmission signals from the base station 100 and the base station 101 and performs cooperative communication can suppress interference from adjacent cells by performing despreading, and perform cooperative communication. It is possible to estimate the optimum feedback information for performing.
  • the mobile terminal device 151 that does not perform cooperative communication increases new processing by using each chip independently without performing despreading processing, even if the reference symbol sequence is based on a pseudo-noise sequence. And optimal feedback information can be estimated. Furthermore, even when an antenna port is added, resource overhead due to reference symbols can be prevented from increasing.
  • the reference symbol sequence based on the pseudo noise sequence is used for all the reference symbols of all the antenna ports.
  • a reference symbol sequence based on a pseudo noise sequence may be assigned to a reference symbol in one antenna port, and a reference symbol generated from a random number based on a cell ID may be assigned to reference symbols in the remaining antenna ports.
  • the reference symbol sequence based on the pseudo noise sequence is used for all the resource elements that map the reference symbols of the respective antenna ports.
  • the number of antenna ports to be newly added is four in the base station apparatuses 100 and 101 has been described above, the number of antenna ports to be added is not limited to four and may be one or more antenna ports. . Although the case where there are reference symbols for the antenna ports 1 to 4 has been described above, these may not be necessary. In the above description, four antenna ports are further added to the four antenna ports 1 to 4. However, the present invention is not limited to this, and one or more antenna ports are provided for one or more antenna ports. Any port may be added. For example, six antenna ports may be newly added to the two antenna ports 1 and 2. Note that the method described in this embodiment may be applied in combination with the methods described in the second to fourth embodiments.
  • FIG. 18 is a conceptual diagram illustrating an example in which the base station apparatus 100 maps reference symbol sequences for one sequence to a plurality of resource blocks in the frequency direction of the nth subframe.
  • the reference symbol sequences of the antenna ports 5 to 8 are indicated by 5 to 8, respectively, and the reference symbols of the antenna ports 1 to 4 are the network symbols. Shown with a hanger.
  • the communication system in the present embodiment includes base station apparatuses 100 and 101 and mobile terminal apparatuses 150 and 151 similar to the communication system in the first embodiment, but the mapping method of the resource element mapping unit is different. Below, it demonstrates centering on a different part from 1st Embodiment.
  • Base station apparatuses 100 and 101 of the present embodiment further include antenna ports 5 to 8 in addition to antenna ports 1 to 4 included in the first embodiment.
  • FIG. 18 illustrates mapping of reference symbol sequences performed by the base station apparatus 100.
  • the reference signal generation unit 29 generates a reference symbol sequence based on the pseudo noise sequence, and the resource element mapping units 301 to 30T map the reference symbol sequence generated for each subband unit composed of a plurality of resource blocks in the frequency direction.
  • the subband is a resource unit for creating feedback information, and is determined in advance based on the system band or the like.
  • FIG. 18 shows the k-th subband SB (k) including m-th to (m + 3) resource blocks RB (m) to RB (m + 3).
  • the reference signal generation unit 29 generates an 8-chip reference symbol sequence to be assigned to the newly added antenna ports 5 to 8 over four resource blocks based on the pseudo noise sequence.
  • the reference signal generation unit 29 generates a reference symbol sequence using a pseudo noise sequence having excellent autocorrelation characteristics such as an M sequence.
  • base station apparatus 101 uses a series of base station apparatus 100 that is cyclically shifted by one chip as a reference symbol series. Further, the resource element that maps the reference symbol sequence may be shifted between adjacent cells based on the cell ID or the like.
  • the reference symbol sequence transmitted from the base station apparatus 100 and the reference symbol sequence transmitted from the base station apparatus 101 are different from each other and orthogonal to each other.
  • the mobile terminal apparatus 150 that simultaneously receives transmission signals from the base station 100 and the base station 101 and performs cooperative communication can suppress interference from adjacent cells by performing despreading, and perform cooperative communication. It is possible to estimate the optimum feedback information for performing.
  • the mobile terminal device 151 that does not perform cooperative communication increases new processing by using each chip independently without performing despreading processing, even if the reference symbol sequence is based on a pseudo-noise sequence. And optimal feedback information can be estimated.
  • the gain due to despreading can be increased without increasing the resource overhead due to the reference symbol. Furthermore, even when a new antenna port is added, the resource overhead due to the reference symbol can be prevented from increasing without reducing the gain due to despreading.
  • the case where the generation and mapping of the reference symbol sequence based on the pseudo noise sequence is performed in subband units composed of a plurality of resource blocks continuous in the frequency direction has been described.
  • the resource block may be included.
  • the case where the generation and mapping of the reference symbol sequence based on the pseudo-noise sequence is performed using four resource blocks in the frequency direction as a unit has been described, but two or more resource blocks may be used as a unit.
  • the mapping may be performed over the carrier element (component carrier) unit or the entire system band.
  • the carrier element has a narrower frequency band (in this embodiment, a bandwidth of 20 MHz) that constitutes a system band (a wideband frequency band having a bandwidth of 100 MHz in this embodiment). Narrow frequency band).
  • a unit in which a specific physical channel (for example, PDCCH (Physical downlink control channel), PUCCH (Physical uplink control channel), etc.) is configured may be used as a carrier element.
  • PDCCH Physical downlink control channel
  • PUCCH Physical uplink control channel
  • the reference symbol sequence based on the pseudo noise sequence is used for all reference symbols of the antenna port to be newly added, but only a part of them may be used.
  • a reference symbol sequence based on a pseudo-noise sequence may be assigned to a reference symbol in one antenna port, and a reference symbol generated from a random number based on a cell ID may be assigned to reference symbols in the remaining antenna ports.
  • the reference symbol sequence based on the pseudo noise sequence is used for all the reference symbols for all antenna ports has been described. However, only the reference symbols based on the pseudo noise sequence are used for some reference symbols. Also good.
  • the number of antenna ports to be newly added is four in the base station apparatuses 100 and 101 has been described above, the number of antenna ports to be added is not limited to four and may be one or more antenna ports. . Although the case where there are reference symbols for the antenna ports 1 to 4 has been described above, these may not be necessary. Although the case where the reference symbol series is arranged in all the resource blocks has been described above, the reference symbol series may be arranged only in some resource blocks. In the above description, four antenna ports are further added to the four antenna ports 1 to 4. However, the present invention is not limited to this, and one or more antenna ports are provided for one or more antenna ports. Any port may be added. For example, six new antenna ports may be added to the two antenna ports 1 and 2. Note that the method described in this embodiment may be applied in combination with the methods described in the second to fifth embodiments.
  • FIG. 19 is a conceptual diagram illustrating an example in which the base station apparatus 100 maps one sequence of reference symbol sequences to a plurality of resource blocks in the time direction.
  • the reference symbol sequences of the antenna ports 5 to 8 are indicated by 5 to 8, respectively, and the reference symbols of the antenna ports 1 to 4 are shaded.
  • the communication system according to the present embodiment includes base station apparatuses 100 and 101 and mobile terminal apparatuses 150 and 151 similar to the communication system according to the first embodiment, but the mapping method of the resource element mapping unit In the following, the description will focus on parts that are different from the first embodiment.
  • Base station apparatuses 100 and 101 of the present embodiment further include antenna ports 5 to 8 in addition to antenna ports 1 to 4 included in the first embodiment.
  • the reference signal generation unit 29 generates an 8-chip reference symbol sequence based on the pseudo noise sequence, and the resource element mapping units 301 to 30T map the reference symbol sequence for each of a plurality of resource block units in the time direction. In FIG.
  • the reference signal generation unit 29 generates an 8-chip reference symbol sequence to be assigned to newly added antenna ports 5 to 8 over four resource blocks based on the pseudo noise sequence.
  • the reference signal generation unit 29 generates a reference symbol sequence using a pseudo noise sequence having excellent autocorrelation characteristics such as an M sequence.
  • base station apparatus 101 uses a series of base station apparatus 100 that is cyclically shifted by one chip as a reference symbol series. Further, the resource element that maps the reference symbol may be shifted between adjacent cells based on the cell ID or the like.
  • the reference symbol sequence transmitted by the base station apparatus 100 and the reference symbol sequence transmitted by the base station apparatus 101 are different from each other and orthogonal to each other.
  • the mobile terminal apparatus 150 that simultaneously receives transmission signals from the base station 100 and the base station 101 and performs cooperative communication can suppress interference from adjacent cells by performing despreading, and perform cooperative communication. It is possible to estimate the optimum feedback information for performing.
  • the mobile terminal device 151 that does not perform cooperative communication increases new processing by using each chip independently without performing despreading processing, even if the reference symbol sequence is based on a pseudo-noise sequence. And optimal feedback information can be estimated.
  • the gain due to despreading can be increased without increasing the resource overhead due to the reference symbol. Furthermore, even when a new antenna port is added, the resource overhead due to the reference symbol can be prevented from increasing without reducing the gain due to despreading.
  • the case where the generation and mapping of the reference symbol sequence based on the pseudo-noise sequence is performed in units composed of a plurality of resource blocks continuous in the time direction has been described. Blocks may be included.
  • the case where the generation and mapping of the reference symbol sequence based on the pseudo-noise sequence is performed in units of four resource blocks in the time direction has been described, but two or more resource blocks may be used as a unit.
  • BCH Broadcast information channel
  • synchronization channel synchronization channel
  • the reference symbol sequence is mapped based on the pseudo-noise sequence to the unit configured by a plurality of resource blocks in the time direction.
  • the unit configured by a plurality of resource blocks in the time direction has been described.
  • one or more OFDM symbols in the time direction have been described. Any unit may be used.
  • the reference symbol sequence based on the pseudo noise sequence is used for all reference symbols of the antenna port to be newly added, but only a part of them may be used.
  • a reference symbol sequence based on a pseudo-noise sequence may be assigned to a reference symbol in one antenna port, and a reference symbol generated from a random number based on a cell ID may be assigned to reference symbols in the remaining antenna ports.
  • the reference symbol sequence based on the pseudo noise sequence is used for all the reference symbols for all antenna ports. However, only the reference symbol sequence based on the pseudo noise sequence is used for some reference symbols. May be.
  • the number of antenna ports to be newly added is four in the base station apparatuses 100 and 101 has been described above, the number of antenna ports to be added is not limited to four and may be one or more antenna ports. . Although the case where there are reference symbols for the antenna ports 1 to 4 has been described above, these may not be necessary. Although the case where the reference symbol series is arranged in all the resource blocks has been described above, the reference symbol series may be arranged only in some resource blocks. In the above description, four antenna ports are further added to the four antenna ports 1 to 4. However, the present invention is not limited to this, and one or more antenna ports are provided for one or more antenna ports. Any port may be added. For example, six new antenna ports may be added to the two antenna ports 1 and 2. Note that the method described in this embodiment may be applied in combination with the methods described in the second to sixth embodiments.
  • FIG. 20 is a conceptual diagram illustrating an example in which the base station apparatus 100 maps one series of reference symbol sequences to a plurality of antenna ports.
  • reference symbol sequences of antenna ports 5 to 8 are indicated by 5 to 8, respectively, and reference symbols of antenna ports 1 to 4 are indicated by shading.
  • the communication system in the present embodiment includes base station apparatuses 100 and 101 and mobile terminal apparatuses 150 and 151 similar to the communication system in the first embodiment, but the mapping method of the resource element mapping unit is different. Below, it demonstrates centering on a different part from 1st Embodiment.
  • Base station apparatuses 100 and 101 of the present embodiment further include antenna ports 5 to 8 in addition to antenna ports 1 to 4 included in the first embodiment.
  • the reference signal generation unit 29 generates an 8-chip reference symbol sequence based on the pseudo noise sequence, and the resource element mapping units 301 to 30T reference within the same resource block over the four antenna ports of the antenna ports 5 to 8. A symbol series is assigned and this is repeated for each resource block.
  • the reference signal generation unit 29 generates an 8-chip reference symbol sequence to be allocated over the four newly added antenna ports 5 to 8 based on the pseudo noise sequence.
  • the reference signal generation unit 29 generates a reference symbol sequence using a pseudo noise sequence having excellent autocorrelation characteristics such as an M sequence.
  • base station apparatus 101 uses a series of base station apparatus 100 that is cyclically shifted by one chip as a reference symbol series. Further, the resource element that maps the reference symbol may be shifted between adjacent cells based on the cell ID or the like.
  • the reference symbol sequence transmitted by the base station device 100 and the reference symbol sequence transmitted by the base station device 101 are different from each other and orthogonal to each other.
  • the mobile terminal apparatus 150 that simultaneously receives transmission signals from the base station 100 and the base station 101 and performs cooperative communication can suppress interference from adjacent cells by performing despreading, and perform cooperative communication. It is possible to estimate the optimum feedback information for performing.
  • the mobile terminal device 151 that does not perform cooperative communication increases new processing by using each chip independently without performing despreading processing, even if the reference symbol sequence is based on a pseudo-noise sequence. And optimal feedback information can be estimated.
  • the gain due to despreading can be increased without increasing the resource overhead due to the reference symbol. Furthermore, even when a new antenna port is added, the resource overhead due to the reference symbol can be prevented from increasing without reducing the gain due to despreading.
  • the reference symbol sequence based on the pseudo noise sequence is used for all the resource elements that map the reference symbols across all antenna ports, but the pseudo noise sequence is applied only to some of the reference symbols.
  • a reference symbol sequence based on the above may be used.
  • the number of antenna ports to be newly added is four in the base station apparatuses 100 and 101 has been described above, the number of antenna ports to be added is not limited to four, and may be two or more antenna ports. .
  • the case where there are reference symbols for the antenna ports 1 to 4 has been described above, these may not be necessary.
  • the reference symbol series is arranged in all the resource blocks has been described above, the reference symbol series may be arranged only in some resource blocks.
  • the present invention is not limited to this.
  • six new antenna ports may be added to the two antenna ports 1 and 2.
  • the method described in this embodiment may be applied in combination with the methods described in the second to seventh embodiments.
  • FIG. 21A is a conceptual diagram illustrating an example of a reference symbol sequence based on an orthogonal code sequence used by the base station apparatuses 100 and 101 for the antenna port 1.
  • the code C1 in the figure is a reference symbol sequence used by the base station apparatus 100 for the antenna port 1
  • the code C2 is a reference symbol series used by the base station apparatus 101 for the antenna port 1.
  • FIG. 21B is a conceptual diagram illustrating an example of a reference symbol sequence based on an orthogonal code sequence used by the base station apparatuses 100 and 101 for the antenna port 2.
  • the reference symbol C1 ′ in the figure is a reference symbol sequence used by the base station device 100 for the antenna port 2
  • the reference symbol C2 ′ is a reference symbol sequence used by the base station device 101 for the antenna port 2.
  • FIG. 21C is a conceptual diagram illustrating an example in which the base station apparatus 100 maps a reference symbol sequence.
  • reference symbol sequences of antenna ports 1 and 2 of base station apparatus 100 are indicated by a to d and i to l, respectively.
  • FIG. 21D is a conceptual diagram illustrating an example in which the base station apparatus 101 maps reference symbol sequences.
  • reference symbol sequences of antenna ports 1 and 2 of the base station apparatus 101 are indicated by e to h and m to p, respectively.
  • the communication system according to the ninth embodiment includes base station apparatuses 100 and 101 and mobile terminal apparatuses 150 and 151 similar to the communication system according to the first embodiment, but performs mapping with the mapping method of the resource element mapping unit. The series is different. Below, it demonstrates centering on a different part from 1st Embodiment. In this embodiment, antenna ports 1 and 2 are used.
  • reference symbol sequences (4 chips) assigned to newly added antenna ports 1 to 2 across four resource blocks are orthogonal code sequences (cross-correlation characteristics) such as OVSF (OrthogonalthoVariable Spreading Factor) codes. This is a case where it is generated on the basis of an excellent series.
  • Base station apparatuses 100 and 101 use abcd (orthogonal code C1) and efgh (orthogonal code C2) orthogonal to each other as orthogonal codes used for antenna port 1, and ijkl (orthogonal to each other) as orthogonal codes used for antenna port 2.
  • Orthogonal code C1 ′) and mnop (orthogonal code C2 ′) are used.
  • the same code set may be used as the set of orthogonal codes C1 and 2 and the set of orthogonal codes C1 'and 2'.
  • a set of orthogonal codes C1 and 2 and a set of orthogonal codes C1 ′ and 2 ′ are set from the 4-chip OVSF sequences 1111, 11-1-1, 1-1-11, and 1-11-1. You may do it.
  • Sequences orthogonal to each other are used between adjacent base station apparatuses (cells). Further, the orthogonal relationship can be maintained by making the resource elements for mapping the reference symbol sequence the same between adjacent cells.
  • the power (or amplitude) of the reference symbol mapped to each resource element is preferably the same as the power (or amplitude) of the data symbol mapped to the resource element of the data part.
  • mobile terminal apparatuses 150 that simultaneously receive transmission signals from base station 100 and base station 101 and perform coordinated communication perform despreading, respectively.
  • Signal power (signal amplitude) from each base station can be measured while eliminating interference from neighboring cells, and optimal feedback for cooperative communication from the signal power (signal amplitude) obtained by each base station Information (CQI and PMI based on total SINR and total SINR, SINR in each base station, CQI and PMI based on SINR in each base station, and the like) can be estimated.
  • CQI and PMI based on total SINR and total SINR, SINR in each base station, CQI and PMI based on SINR in each base station, and the like
  • the mobile terminal device 151 that does not perform cooperative communication refers to the reference symbol sequence transmitted from the base station device (own base station, own cell, serving cell) 100 that performs communication, and receives the received reference symbol sequence.
  • the signal power (signal amplitude) obtained from the base station apparatus 100 can be measured while removing interference from adjacent cells.
  • each reference symbol sequence chip includes an interference component from an adjacent base station, the reference symbol sequence is mapped to the resource element to which the reference symbol sequence is mapped (the amplitude and reception of the reference signal from the own base station).
  • the average interference signal power can be obtained by calculating the square norm of the signal and the difference, and optimum feedback information (such as CNR and PMI based on SINR and SINR) can be estimated.
  • a communication system in which one base station apparatus 100 and at least one mobile terminal apparatus 151 communicate with each other, and a plurality of base station apparatuses 100 and 101 communicate with each other in cooperation with at least one mobile terminal apparatus 150.
  • the base station apparatus 100 generates a reference symbol sequence shared by both the mobile terminal apparatus 150 that performs cooperative communication and the mobile terminal apparatus 151 that does not perform cooperative communication, and maps the reference symbol to one of the resource elements.
  • Base station apparatuses 100 and 101 use sequences orthogonal between base station apparatuses as reference symbol sequences, and map reference symbol sequences to the same resource elements between base station apparatuses.
  • the mobile terminal device 151 that communicates with one base station device 100 uses the reference symbol sequence transmitted by the communication partner base station device 100 to measure the state of the transmission path for notifying the communication partner base station device 100. . Further, mobile terminal apparatus 150 that communicates in cooperation with a plurality of base station apparatuses 100 and 101 notifies each of base station apparatuses 100 and 101 from a reference symbol sequence transmitted by each of a plurality of base station apparatuses 100 and 101. Measure the transmission path conditions for As a result, the mobile terminal device 150 that performs cooperative communication and the mobile terminal device 151 that does not perform cooperative communication use the same reference symbol sequence, and the mobile terminal device 150 that performs cooperative communication transmits signals from the base station devices 100 and 101.
  • the mobile terminal apparatus 151 that can accurately grasp the transmission signal power and does not perform cooperative communication accurately grasps the transmission signal power from the own base station apparatus 100 and also averages the interference signal from the adjacent base station apparatus 101. Electric power can be obtained. Accordingly, the mobile terminal apparatus 100 that performs cooperative communication and the mobile terminal apparatus 101 that does not perform cooperative communication can generate optimal feedback information while sharing the reference symbol sequence and suppressing overhead.
  • a program for realizing the functions of all or part of base station apparatus 100 in FIG. 4 and all or part of mobile station apparatus 150 in FIG. 6 is recorded on a computer-readable recording medium. Processing of each unit may be performed by causing a computer system to read and execute a program recorded on a recording medium.
  • the “computer system” here includes an OS and hardware such as peripheral devices. Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
  • the “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM or a CD-ROM, and a hard disk incorporated in a computer system.
  • the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line.
  • a volatile memory in a computer system serving as a server or a client in that case and a program that holds a program for a certain period of time are also included.
  • the program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.
  • the present invention is suitable for use in a wireless communication system, a wireless communication apparatus, and a wireless communication method.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Dans un système de communication sans fil, un appareil de communication placé à une extrémité d'émission comprend une unité de génération de signal de référence qui générant, en tant que symboles de référence devant être transmis conjointement avec les données transmises, une séquence de symboles de référence sur la base d'une séquence de pseudos bruits. Un appareil de communication placé à une extrémité de réception peut utiliser la séquence de symboles de référence générés par l'unité de génération de signal de référence pour déterminer un état de réception de signal avec suppression ou réduction de l'interférence avec le signal de référence.
PCT/JP2010/002748 2009-04-24 2010-04-15 Système de communication, appareil de communication et procédé de communication WO2010122749A1 (fr)

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JP2012114607A (ja) * 2010-11-24 2012-06-14 Sharp Corp 無線通信システム、基地局装置、移動局装置及び無線通信システムにおける通信方法
JP2012175191A (ja) * 2011-02-17 2012-09-10 Sharp Corp 通信システム、基地局装置、端末装置
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US10044432B2 (en) 2011-04-19 2018-08-07 Sun Patent Trust Relay method and relay device
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US10623084B2 (en) 2011-04-19 2020-04-14 Sun Patent Trust Relay method and relay device
US11658733B2 (en) 2011-04-19 2023-05-23 Sun Patent Trust Base station and communication scheme executed by a base station
JP2017055449A (ja) * 2013-01-03 2017-03-16 インテル コーポレイション 改良されたチャネル品質情報フィードバック方式
US9986477B2 (en) 2013-01-03 2018-05-29 Intel Corporation Channel quality information feedback techniques
JPWO2016163499A1 (ja) * 2015-04-09 2018-02-22 株式会社Ｎｔｔドコモ 無線基地局、ユーザ端末及び無線通信方法
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JP2020512727A (ja) * 2017-02-28 2020-04-23 華為技術有限公司Ｈｕａｗｅｉ Ｔｅｃｈｎｏｌｏｇｉｅｓ Ｃｏ．，Ｌｔｄ． スケジューリング方法、基地局、および端末
CN110337824A (zh) * 2017-02-28 2019-10-15 华为技术有限公司 一种调度的方法、基站及终端
CN112637956B (zh) * 2017-02-28 2024-07-16 华为技术有限公司 一种调度的方法、基站及终端

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