WO2015040659A1 - Procédé de radiocommunication, système de radiocommunication, station de base radio, et terminal radio - Google Patents

Procédé de radiocommunication, système de radiocommunication, station de base radio, et terminal radio Download PDF

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Publication number
WO2015040659A1
WO2015040659A1 PCT/JP2013/005599 JP2013005599W WO2015040659A1 WO 2015040659 A1 WO2015040659 A1 WO 2015040659A1 JP 2013005599 W JP2013005599 W JP 2013005599W WO 2015040659 A1 WO2015040659 A1 WO 2015040659A1
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Prior art keywords
base station
radio
transmission
downlink
wireless
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PCT/JP2013/005599
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English (en)
Japanese (ja)
Inventor
耕太郎 椎▲崎▼
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富士通株式会社
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Priority to PCT/JP2013/005599 priority Critical patent/WO2015040659A1/fr
Publication of WO2015040659A1 publication Critical patent/WO2015040659A1/fr

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    • 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
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H04B7/024—Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/20—Control channels or signalling for resource management
    • H04W72/23—Control channels or signalling for resource management in the downlink direction of a wireless link, i.e. towards a terminal
    • 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
    • H04L5/0091—Signaling for the administration of the divided path
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W92/00—Interfaces specially adapted for wireless communication networks
    • H04W92/16—Interfaces between hierarchically similar devices
    • H04W92/20—Interfaces between hierarchically similar devices between access points

Definitions

  • the present invention relates to a radio communication method, a radio communication system, a radio base station, and a radio terminal.
  • LTE Long Term Evolution
  • LTE-A Long Term Evolution-A
  • LTE-A LTE-A
  • CoMP Coordinatd Multiple Point
  • CoMP is a general term for technologies that coordinate transmission / reception with respect to wireless terminals between different wireless base stations.
  • transmission methods categories
  • Increasing the capacity of wireless communications has become an issue due to the widespread use of smartphones, and the importance of CoMP is expected to increase in the future.
  • the backhaul refers to a wired or wireless network that connects between wireless base stations or connects a wireless base station to a core network.
  • the non-ideal backhaul refers to a non-ideal backhaul, and specifically means a backhaul with a relatively large delay.
  • a backhaul with a relatively small delay is called an ideal backhaul.
  • an ideal backhaul was assumed, but it is assumed that high-speed backhaul laying using optical fibers is difficult. It is expected that the examination will be activated.
  • the disclosed technology has been made in view of the above, and provides a wireless communication method, a wireless communication system, a wireless base station, and a wireless terminal that can eliminate inconveniences that occur in CoMP based on non-ideal backhaul. Objective.
  • the disclosed wireless communication method is such that the first wireless base station and the second wireless base station cooperate with the first wireless terminal among the one or more wireless terminals.
  • a radio communication method for performing coordinated transmission for transmitting radio signals wherein the first radio base station transmits downlink scheduling information for performing the coordinated transmission to one of the one or more radio terminals.
  • the second radio terminal Transmitting to the radio terminal, transmits the downlink scheduling information to the second radio base station.
  • the wireless communication system, the wireless base station, and the wireless terminal disclosed in this case there is an effect that it is possible to eliminate inconveniences that occur in CoMP based on a non-ideal backhaul.
  • FIG. 1A to 1C are diagrams for explaining the concept of each CoMP method.
  • FIG. 2 is a diagram for explaining DPS, which is one method of CoMP.
  • FIG. 3 is a diagram for explaining the location of a problem in the present application.
  • FIG. 4 is a diagram for explaining the location of a problem in the present application.
  • FIG. 5 is a diagram showing an example of a processing sequence in the first embodiment of the present application.
  • FIG. 6 is a diagram showing an example of a processing sequence in the first embodiment of the present application.
  • FIG. 7 is a diagram illustrating an example of a processing sequence in the second embodiment of the present application.
  • FIG. 8 is a diagram illustrating an example of a network configuration of the wireless communication system according to each embodiment.
  • FIG. 1A to 1C are diagrams for explaining the concept of each CoMP method.
  • FIG. 2 is a diagram for explaining DPS, which is one method of CoMP.
  • FIG. 3 is a diagram for explaining the location of a problem
  • FIG. 9 is an example of a functional configuration diagram of a radio base station in the radio communication system of each embodiment.
  • FIG. 10 is an example of a functional configuration diagram of a wireless terminal in the wireless communication system of each embodiment.
  • FIG. 11 is an example of a hardware configuration diagram of a radio base station in the radio communication system of each embodiment.
  • FIG. 12 is an example of a hardware configuration diagram of a wireless terminal in the wireless communication system of each embodiment.
  • TP Transmission Point
  • TP is a concept that substantially corresponds to a radio base station. Therefore, in the present application, unless otherwise noted, the radio base station may be appropriately read as TP.
  • JT joint transmission
  • DPS dynamic point selection
  • SSPS semi-static point selection
  • CS coordinated scheduling
  • CB coordinated beamforming
  • FIG. 1A is a diagram illustrating the concept of JT, which is one of CoMP.
  • JT is a method in which a plurality of radio base stations 10a and 10b simultaneously transmit (joint transmission) the same data addressed to a certain radio terminal 20, and improve the reception quality and throughput addressed to the radio terminal 20.
  • FIG. 1B is a diagram showing the concept of DPS and SSPS, which are one of CoMP.
  • DPS the same data addressed to the radio terminal 20 is simultaneously present in a plurality of radio base stations 10a and 10b. However, data transmission addressed to the radio terminal 20 is performed from a single radio base station 10a and other base stations 10b. Is blanking, i.e. not transmitting. This enables instantaneous dynamic cell (base station) selection that follows fading fluctuations rather than normal cell (base station) selection in an LTE system based on time-averaged channel conditions.
  • SSPS is similar in concept to DPS, but cell switching is more gradual than PDS which switches cells every subframe.
  • FIG. 1C is a diagram showing the concept of CS and CB, which are one of CoMP.
  • CS and CB are transmitted from a single radio base station 10a or 10b to a radio terminal 20a or 20b in a certain subframe, and other radio base stations 10b or 10a reduce interference given to the transmission. It behaves like Here, in CS, other radio base stations perform muting to reduce interference with transmission by radio base station 10a or 10b. In CB, other radio base stations 10b or 10a perform beamforming. To reduce interference with transmission by the radio base station 10a or 10b.
  • FIG. 2 exemplifies a processing sequence in the case of executing DPS, which is one of the CoMP schemes, by the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c, which are three base stations. Yes.
  • DPS which is one of the CoMP schemes
  • the serving base station 10a the serving base station 10a
  • the first cooperative base station 10b the first cooperative base station 10b
  • the second cooperative base station 10c which are three base stations. Yes.
  • other CoMP schemes can be implemented by a similar processing sequence.
  • downlink data for example, download file
  • the serving base station 10a needs to perform scheduling for transmitting downlink data to the radio terminal 20.
  • scheduling the presence / absence of application of DPS, the transmission base station in DPS, transmission parameters for performing DPS, and the like are determined.
  • the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c each transmit a downlink reference signal in S102a to S102c of FIG.
  • the radio terminal 20 measures the quality of the downlink with each base station based on these reference signals. Thereafter, in S103, the radio terminal 20 feeds back a CQI (Channel Quality Indicator) indicating the downlink quality measured for each base station to the serving base station 10a.
  • CQI Channel Quality Indicator
  • the serving base station 10a performs the above-described scheduling based on the received CQI.
  • the serving base station 10a can determine the base station with the best downlink radio quality indicated by CQI as the DPS transmission base station.
  • the serving base station 10a has decided to transmit downlink data by DPS using the first coordinated base station 10b as a transmission base station.
  • the serving base station 10a also uses the modulation coding scheme (MCS: Modulation and Coding Scheme) and the resource block (sub-scheme) used for transmission of downlink data from the first cooperative base station 10b to the radio terminal 20 based on CQI.
  • MCS Modulation and Coding Scheme
  • Transmission parameters such as (carrier) can also be determined.
  • the transmission base station determined in S104 and these transmission parameters are collectively referred to as downlink scheduling information here.
  • the serving base station 10a transmits downlink data and downlink scheduling information to the first cooperative base station 10b via the backhaul based on the scheduling result in S104.
  • the serving base station 10a transmits downlink scheduling information to the second coordinated base station 10c via the backhaul based on the scheduling result in S104.
  • downlink data is transmitted to the first coordinated base station 10b which is a transmission base station, but is not transmitted to the second coordinated base station 10c which is not a transmission base station.
  • Figure 2 assumes an ideal backhaul. Therefore, the delay in signal transmission / reception via the backhaul in S105 and S106 is minimal.
  • the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c cooperate in downlink by DPS using the first cooperative base station 10b as a transmission base station.
  • Data is transmitted to the wireless terminal 20.
  • the first cooperative base station 10b which is a transmission base station in S107b, transmits downlink data to the radio terminal 20 based on the downlink scheduling information received in S105.
  • the serving base station 10a performs blanking (no transmission) to the radio terminal 20 based on its scheduling result in S104.
  • the second coordinated base station 10c performs blanking for the radio terminal 20 based on the downlink scheduling information received in S106.
  • DPS which is one of the CoMP schemes, can be executed appropriately in response to downlink radio quality.
  • FIG. 3 illustrates a processing sequence in the case of applying DPS, which is one of the CoMP schemes, but other CoMP schemes can be implemented by a similar processing sequence.
  • the transmission base station is determined to be the first coordinated base station 10b, and downlink data transmission parameters (MCS, resource block, etc.) are determined.
  • the serving base station 10a transmits downlink data and downlink scheduling information to the first cooperative base station 10b via the backhaul based on the scheduling result of S204.
  • the serving base station 10a transmits downlink scheduling information to the second coordinated base station 10c via the backhaul based on the scheduling result in S204.
  • FIG. 3 assumes a non-ideal backhaul. Therefore, the signal transmission / reception delay through the backhaul in S205 and S206 is relatively large. This delay is assumed to be several tens of milliseconds, for example. For this reason, as shown in FIG. 3, it is considered that the reception timing of the signals in S205 and S206 is considerably delayed from the transmission timing.
  • downlink quality measurement and CQI transmission by the wireless terminal 20 as described above are periodically performed. This is because scheduling should be performed based on as new radio quality as possible. On the other hand, when scheduling is performed based on the old radio quality, it is considered that the possibility of the scheduling becoming inappropriate increases.
  • the downlink quality measurement and CQI transmission period (referred to as CQI transmission period for convenience) by the radio terminal 20 is selectively selected from seven values of 2, 5, 10, 20, 40, 80, and 160. Can be set.
  • the unit is a subframe (one subframe is one millisecond).
  • the CQI transmission cycle in FIG. 3 is, for example, 20 subframes (20 milliseconds). It is assumed that the delay in transmitting and receiving the signal in S206 is 40 milliseconds.
  • the CQI transmission cycle (20 milliseconds) elapses from the CQI transmission in S203. Therefore, as illustrated in FIG. 3, before the reception of the signal of S206 is completed, the CQI transmission is performed again in S208 after the downlink reference signal is measured again in S207a to S207c.
  • the CQI transmission in S208 corresponds to the CQI transmission in the next cycle in S203. Thereby, at the timing of S209, scheduling can be performed based on the CQI of S208.
  • the downlink quality of the second cooperative base station 10c exceeds that of the first cooperative base station 10b in the CQI of S208. If it is assumed that the downlink data of S201 (note that it has not been transmitted to the radio terminal 20 at this stage) is scheduled based on the CQI of S208 at the timing of S209, the DPS transmission base station performs the first coordination. It will be determined not the base station 10b but the second cooperative base station 10c. Here, for simplicity, it is assumed that the transmission base station is determined based only on the quality of the downlink radio link.
  • the downlink data is not scheduled in S201 at the timing of S209, and in S210a to S210c of FIG. 3, the downlink data is transmitted by DPS using the first coordinated base station 10b as the transmission base station.
  • the scheduling of S204 it is determined that the downlink data transmission base station is the first cooperative base station 10b, and DPS transmission based on the determination is executed regardless of the subsequent change in downlink quality. It is. Therefore, in the determination of the transmission base station for DPS transmission, a situation occurs in which the latest downlink quality at the time of DPS transmission is not reflected.
  • the first cooperative base station 10b is actually transmitted although the second cooperative base station 10c is supposed to be the transmission base station from the viewpoint of communication efficiency. It becomes a base station.
  • Such a situation should be avoided as much as possible because it leads to a decrease in the throughput of the entire wireless communication system. This point is a major problem in FIG. 3, and further study is considered necessary.
  • the description has focused on the fact that the latest downlink quality at the time of DPS transmission is not reflected in the determination of the transmission base station for DPS transmission.
  • this problem is not limited to the determination of the transmission base station, but extends to the entire downlink scheduling in CoMP transmission.
  • the latest downlink quality at the time of DPS transmission is not reflected in the determination of downlink transmission parameters such as MCS used for DPS transmission and resource block allocation. This leads to a decrease in the throughput of the entire wireless communication system, as described with respect to the transmission base station.
  • FIG. 4 shows the processing sequence for such rescheduling.
  • FIG. 4 is largely the same as FIG. 3 except that information for notifying the result of rescheduling is transmitted after the scheduling of S209. Since this information notifies the scheduling result changed by rescheduling, it will be referred to as downlink scheduling change information.
  • downlink scheduling change information By notifying the downlink scheduling change information to the first coordinated base station 10b and the second coordinated base station 10c, these base stations can recognize the rescheduling result, and coordinated transmission such as DPS according to the change in downlink quality ( CoMP transmission) can be realized.
  • the downlink scheduling change information may be transmitted from the serving base station 10a to the first coordinated base station 10b or the second coordinated base station 10c via the backhaul. Seem.
  • FIG. 4 assumes a non-ideal backhaul. Therefore, when downlink scheduling change information is transmitted via the backhaul, a relatively large delay is involved in the transmission / reception.
  • downlink CoMP transmission for example, DPS
  • downlink scheduling information transmitted from the serving base station 10a to the cooperative base station via the backhaul There is a relatively large delay in reception. Therefore, when the serving base station 10a and the coordinated base station perform CoMP transmission based on downlink scheduling information, the latest downlink state is not reflected in the scheduling information, and thus the CoMP transmission is not appropriately performed. There is a problem that the situation can happen. Furthermore, even when trying to send downlink scheduling information reflecting the latest downlink state, the above problem cannot be solved because a relatively large delay is still involved via the backhaul. Such a problem is thought to be avoided as much as possible because it leads to a decrease in the throughput of the entire wireless communication system.
  • DPS downlink CoMP transmission
  • the first embodiment is an example of an embodiment that solves the above-described problem, and when the serving base station 10a changes the scheduling of cooperative transmission, the change is transmitted via the terminal 20 by the radio signal to the cooperative base station 20b. To send to.
  • the first radio base station and the second radio base station cooperate with each other to transmit a radio signal to the first radio terminal 20 among the one or more radio terminals 20.
  • a radio communication method for performing coordinated transmission wherein the first radio base station transmits downlink scheduling information for performing coordinated transmission to a second radio terminal 20 that is one of the one or more radio terminals 20.
  • the second radio terminal 20 is an embodiment related to a radio communication method for transmitting the downlink scheduling information to the second radio base station.
  • FIG. 5 is a diagram illustrating an example of a processing sequence according to the first embodiment.
  • a radio terminal 20 and a serving base station 10a, a first coordinated base station 10b, and a second coordinated base station 10c, which are three radio base stations 10, appear. .
  • the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c may be collectively referred to simply as a radio base station 10. Further, the first cooperative base station 10b and the second cooperative base station 10c may be collectively referred to simply as the cooperative base stations 10b to 10c.
  • the wireless terminal 20 does not need to be communicating with the serving base station 10a, but is assumed to be under the management (under management) of the serving base station 10a. Further, the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c, which are the three radio base stations 10, are in a cooperative relationship for performing cooperative transmission (CoMP transmission). In the LTE system, this cooperative relationship is defined by a set of radio base stations called a CoMP set. The CoMP set is notified in advance from the serving base station 10a to the radio terminal 20, so that the radio terminal 20 can communicate with the radio base stations 10 other than the serving base station 10a belonging to the CoMP set (the first coordinated base station 10b in FIG. 2 cooperative base stations 10c).
  • the above-described non-ideal backhaul is assumed. Therefore, it should be noted that a relatively large delay of, for example, several tens of milliseconds occurs in communication via the backhaul among the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c.
  • FIG. 5 shows an example of applying DPS, which is one of the CoMP methods, but it should be noted that this is only an example. The present invention is applicable regardless of the CoMP method.
  • downlink data is generated in the serving base station 10a.
  • Downlink data is data addressed to the radio terminal 20, and includes high-layer control signals (RRC signals and the like) in addition to user data (application data).
  • RRC signals and the like high-layer control signals
  • downlink data (user data) is generated in the wireless base station 10 located between the server and the wireless terminal 20.
  • the radio base station 10 transmits an RRC control signal to the radio terminal 20, downlink data is generated in the base station.
  • the downlink data generated in the radio base station 10 includes not only data generated from the radio base station 10 but also data generated by other devices and relayed by the radio base station 10. Please note.
  • the serving base station 10a transmits a downlink reference signal.
  • some downlink reference signals are defined.
  • a cell-specific reference signal Cell-specific reference signal
  • CSI Channel State information reference signal
  • the first coordinated base station 10b also transmits a downlink reference signal
  • the second coordinated base station 10c also transmits a downlink reference signal. These can be performed similarly to S302a. Note that S302a to S302c may be transmitted in the same subframe or in different subframes.
  • the wireless terminal 20 receives a downlink reference signal from the serving base station 10a.
  • the radio terminal 20 also receives a downlink reference signal from the first coordinated base station 10b, and in S302c, the radio terminal 20 also receives a downlink reference signal from the second coordinated base station 10c.
  • the radio terminal 20 measures the radio quality (downlink radio quality) from each radio base station 10 to the radio terminal 20 based on each received downlink reference signal.
  • the radio quality for example, a signal-to-noise power ratio (SNR: “Signal-to-Noise-power” Ratio), a signal-to-noise interference power ratio (SINR: “Signal-to-Interference” plus “Noise-power” Ratio), and the like can be used.
  • the radio terminal 20 generates CQI (Channel Quality Indicator) based on the downlink radio quality.
  • CQI is an index indicating downlink channel quality and is one of uplink control information defined in the LTE system. As the CQI is fed back to the radio base station 10, the radio base station 10 can grasp the downlink channel quality and can perform downlink scheduling and the like.
  • the radio terminal 20 transmits the CQI generated based on the downlink reference signals in S302a to S302c to the serving base station 10a.
  • the CQI is transmitted through a physical uplink control channel (PUCCH: “Physical” Uplink “Control” CHannel) or a physical uplink shared channel (PUSCH: “Physical” Uplink “Shared” CHannel).
  • PUCCH Physical Uplink control channel
  • PUSCH Physical uplink shared channel
  • the three CQIs generated in S302a to S302c may be transmitted in the same subframe or in different subframes.
  • the serving base station 10a performs scheduling for transmitting the downlink data generated in S301 based on the CQI received in S303.
  • the serving base station 10a makes various decisions for transmitting the downlink data generated in S301. In the following, these determinations will be described in order.
  • the serving base station 10a first determines the radio base station 10 (hereinafter referred to as a transmission base station for convenience) that transmits the downlink data generated in S301.
  • a transmission base station for convenience
  • downlink data generated in the serving base station 10 a is transmitted to the radio terminal 20 by the serving base station 10 a.
  • CoMP is applied in the present application
  • downlink data generated in the serving base station 10a can be transmitted to the radio terminal 20 other than the serving base station 10a (of course, the serving base station 10a transmits the downlink data). Needless to say, you can do that.)
  • the transmission base station is selected from the radio base stations 10 included in the aforementioned CoMP set.
  • the CoMP set includes three serving base stations 10a, a first coordinated base station 10b, and a second coordinated base station 10c, the serving base station 10a determines a transmission base station from these. It should be noted that the determination of the transmission base station also has an aspect of determining the CoMP scheme. For example, when there are a plurality of transmission base stations, JT, which is one of the CoMP schemes, is inevitably applied.
  • the serving base station 10a can determine the transmission base station based on the CQI received in S303. As an example, based on the CQI received in S303, the serving base station 10a can determine the radio base station 10 with the best downlink quality with the radio terminal 20 as the transmission base station. In this case, DPS or SSPS, which is one of the CoMP methods, is performed. As another example, based on the CQI received in S303, the serving base station 10a transmits the radio base station 10 having the best downlink quality with the radio terminal 20 and the second radio base station 10 as transmission bases. Can be determined as a station. In this case, JT, which is one of the CoMP methods, is performed.
  • the serving base station 10a determines that the serving base station 10a is a transmitting base station based on the CQI received in S303 and requests the coordinated base stations 10b to 10c to reduce interference. It can also be determined. In this case, CS or CB, which is one of the CoMP methods, is performed.
  • the serving base station 10a may determine the transmission base station in consideration of any element other than CQI. As an example, the serving base station 10a receives information on the load from the coordinated base stations 10b to 10c, and when there is only one radio base station 10 whose downlink quality is equal to or higher than a predetermined value and whose load is equal to or lower than a predetermined value.
  • the radio base station 10 can be determined as a transmission base station (for example, DPS is performed).
  • the serving base station 10a can determine the transmission base station based on the downlink radio quality of each radio base station 10 included in the CoMP set, and the load of each radio base station 10.
  • Such determination of the transmission base station is generally performed by scheduling applicable to downlink CoMP transmission in the LTE system, and various conventional techniques are known. Omit. Examples of the load mentioned here include data rates handled by the radio base station 10, radio resource usage rates, operating rates of hardware such as processors of the radio base station 10, and members mounted on the radio base station 10. This corresponds to the amount of heat generated.
  • the serving base station 10a next determines a parameter (hereinafter referred to as a downlink transmission parameter for convenience) for causing the previously determined transmission base station to transmit the downlink data generated in S301.
  • the downlink transmission parameters include various parameters for transmitting or receiving downlink data.
  • the downlink transmission parameters can include, for example, various parameters included in downlink control information (DCI: Downlink Control Information) defined by the LTE system.
  • DCI Downlink Control Information
  • Several formats are defined in DCI.
  • DCI format 1 is control information accompanying downlink data, and includes various parameters necessary for transmitting and receiving the downlink data.
  • the downlink transmission parameters include, for example, MCS (Modulation and Coding Scheme) indicating a coding scheme and a modulation scheme applied to downlink data, and resource block allocation (Resource Block allocation) indicating a resource block (subcarrier) to which downlink data is mapped. ) Etc. are included. These correspond to the parameters included in the DCI format 1 described above.
  • MCS Modulation and Coding Scheme
  • Resource Block allocation Resource Block allocation
  • the serving base station 10a can determine MCS and resource block allocation that are downlink transmission parameters based on the CQI received in S303. Further, these parameters may be determined in consideration of an arbitrary element other than CQI. Furthermore, these parameters can also be determined in consideration of the relationship with other radio terminals 20 under the serving base station 10a. The determination of these parameters is generally performed in downlink data scheduling in the LTE system, and various conventional techniques are known. Therefore, detailed description thereof is omitted here.
  • the downlink transmission parameter can include information related to the timing at which the transmission base station transmits downlink data. Since the transmission unit on the time axis in the LTE system is a subframe (1 millisecond), this timing is specified by a subframe (downlink subframe). Hereinafter, this information will be referred to as downlink subframe information for convenience.
  • downlink subframe information (including downlink transmission parameters) is transmitted from the serving base station 10a to the coordinated base stations 10b to 10c via the non-ideal backhaul.
  • a delay of several tens of milliseconds occurs in communication via the non-ideal backhaul. Due to this delay, there is a concern that if the transmission timing of the downlink subframe is too early, the notification of the transmission timing (reception of downlink subframe information by the cooperative base stations 10b to 10c) will not be in time for the transmission timing.
  • the transmission timing of the downlink subframe for example, after 50 subframes (after 50 milliseconds) in consideration of the non-ideal backhaul delay.
  • the transmission timing is 10 subframes later (10 milliseconds later). It becomes.
  • the coordinated base stations 10b to 10c can meet the transmission timing of the downlink subframe with a margin.
  • the transmission base station is first determined and then the downlink transmission parameters are determined, but it should be noted that the order of determination is not limited to this.
  • the transmission base station and the downlink transmission parameters can be determined together.
  • the combination of the radio base station 10 and the resource block (subcarrier) with the best CQI is selected, and the radio base station 10 is determined as the transmission base station and A resource block assignment can be determined based on the resource block.
  • the determination of the transmission base station and downlink transmission parameters is not limited to this example, and can be performed based on any method, rule, algorithm, or the like without departing from the spirit of the present application.
  • the serving base station 10a further transmits a parameter for transmitting the previously determined transmission base station and downlink transmission parameter change information to the cooperative base stations 10b to 10c via the uplink (hereinafter referred to as uplink for convenience. Called transmission parameters).
  • the transmission base station and downlink transmission parameters are once determined in S304, but these may be changed according to the subsequent change in the downlink state.
  • uplink transmission parameters for notifying the coordinated base stations 10b to 10c of the changed transmission base station and downlink transmission parameters are determined in advance.
  • the uplink transmission parameters include various parameters for transmitting or receiving change information. Although there is a small difference depending on whether the change information is transmitted using PUCCH or PUSCH, the uplink transmission parameters will be described below as an example when the change information is transmitted using PUSCH. Even when the change information is transmitted by PUCCH, it can be realized in the same manner, but details are omitted.
  • the uplink transmission parameters can include various parameters included in the DCI described above. As described above, several formats are defined for DCI. For example, DCI format 0 is control information that is notified prior to uplink data, and includes various parameters necessary for transmitting and receiving the uplink data. ing.
  • Uplink transmission parameters include, for example, MCS indicating a coding scheme and modulation scheme applied to uplink data, resource block allocation indicating a resource block (subcarrier) to which downlink data is mapped, and the like. These correspond to the parameters included in the DCI format 0 described above.
  • the serving base station 10a can determine MCS and resource block allocation that are uplink transmission parameters based on, for example, measurement results of uplink reference signals (not shown). Further, these parameters may be determined in consideration of arbitrary elements thereof. The determination of these parameters is generally performed in uplink data scheduling in the LTE system, and various conventional techniques are known. Therefore, detailed description thereof is omitted here.
  • the uplink transmission parameter can include information related to the timing at which the transmission base station transmits the change information.
  • this timing is specified by a subframe (uplink subframe).
  • uplink subframe information this information will be referred to as uplink subframe information.
  • the serving base station 10a determines the first coordinated base station 10b as the transmission base station by scheduling in S304.
  • this premise is merely an example for explaining a specific example of processing in the present embodiment. In the following, the description will proceed under this assumption.
  • downlink scheduling information information indicating the transmission base station described above and downlink transmission parameters may be collectively referred to as downlink scheduling information.
  • uplink transmission parameter described above may be referred to as uplink scheduling information.
  • the serving base station 10a transmits a signal including downlink data, downlink scheduling information, and uplink scheduling information to the first coordinated base station 10b via the backhaul.
  • the first cooperative base station 10b receives a signal including downlink data, downlink scheduling information, and uplink scheduling information from the serving base station 10a via the backhaul. It should be noted that the transmission / reception in S305 is performed via a backhaul (non-ideal backhole), so that a relatively large delay occurs.
  • the signal of S305 can be realized by the X2 signal in the LTE system.
  • downlink data, downlink scheduling information, and uplink scheduling information are transmitted and received as a single signal to the first coordinated base station 10b. However, these may be transmitted separately in a plurality of signals. .
  • the serving base station 10a transmits a signal including downlink data, downlink scheduling information, and uplink scheduling information to the second cooperative base station 10c via the backhaul.
  • the second cooperative base station 10c receives a signal including downlink data, downlink scheduling information, and uplink scheduling information from the serving base station 10a via the backhaul. Since S306 may be performed in the same manner as S305, description thereof is omitted.
  • downlink data is transmitted only to the transmission base station, whereas in S305 to S306 in FIG. 5, downlink data is transmitted to all the coordinated base stations 10b to 10c. Be careful about what is done. In this embodiment, since the transmission base station may be changed later, the downlink data is transmitted in advance to all the coordinated base stations 10b to 10c that can become the transmission base station.
  • the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c transmit downlink reference signals to the radio terminal 20, respectively.
  • the radio terminal 20 transmits CQI indicating the downlink quality measured based on the downlink reference signal in S307a to S307c to the serving base station 10a.
  • the serving base station 10a performs downlink data scheduling (rescheduling) in step S301 based on the CQI and the like in step S308.
  • S307 (S307a to S307c) to S309 correspond to the scheduling process performed in the next CQI transmission cycle after S302 to S304. That is, S307 to S309 are performed after the CQI transmission cycle has elapsed from S302 to S304. Thereafter, the same scheduling process is periodically performed every time the CQI transmission period elapses.
  • S307a to S307c and S308 may be performed in the same manner as S302a to S302c and S303, description thereof is omitted here.
  • S309 is the same process as S304, a detailed description thereof will be omitted. However, in the example of processing in the present embodiment shown in FIG. 5, the initial scheduling of downlink data (generated in S301) is performed in S304, whereas the rescheduling of the downlink data is performed in S309. Note that this is done.
  • the serving base station 10 a determines the second coordinated base station 10 c as the transmission base station by scheduling in S ⁇ b> 309. That is, it is assumed that downlink data scheduling (for example, a transmission base station) is changed in S309 due to a change in downlink radio quality or the like from the time of scheduling in S304.
  • downlink data scheduling for example, a transmission base station
  • this premise is merely an example for explaining a specific example of processing in the present embodiment. In the following, the description will proceed under this assumption.
  • the serving base station 10a transmits downlink scheduling change information and uplink scheduling information to the radio terminal 20.
  • the radio terminal 20 receives downlink scheduling change information and uplink scheduling information from the serving base station 10a.
  • the downlink scheduling change information is information indicating the scheduling of the downlink data changed in S309.
  • the information included in the downlink scheduling change information can include transmission base station information and downlink transmission parameters according to the information included in the downlink scheduling information.
  • the downlink scheduling information may include only the contents changed from the downlink scheduling information, or may include all downlink scheduling information based on the latest scheduling.
  • the uplink scheduling information transmitted / received in S310 is the same information that is transmitted from the serving base station 10a to the coordinated base stations 10b to 10c in S305 to S306. As a result, the uplink scheduling information is shared between the radio terminal 20 and each of the cooperative base stations 10b to 10c.
  • downlink scheduling change information and uplink scheduling information are transmitted from the serving base station 10a to the radio terminal 20 via a radio signal (downlink) in S310. It should be noted that although downlink scheduling information and uplink scheduling information are transmitted via the backhaul in S305 to S306, S310 is different from these. The technical significance of transmitting each piece of information via a radio signal in S310 will be described later.
  • the downlink scheduling change information in S310 may be transmitted via PDCCH or may be transmitted via PDSCH.
  • the downlink scheduling change information can be transmitted via the PDSCH by, for example, a downlink RRC signal.
  • the downlink scheduling change information can be transmitted via the PDCCH by the above-described DCI. It should be noted that in downlink transmission, it is not necessary to notify the radio terminal 20 of transmission parameters in advance as in uplink transmission, regardless of whether the transmission is through PDCCH or PDSCH.
  • the radio terminal 20 transmits the downlink scheduling change information received in S310 to the first coordinated base station 10b based on the uplink scheduling information received in S310.
  • the first cooperative base station 10b receives downlink scheduling change information from the radio terminal 20 based on the uplink scheduling information received in S305.
  • the uplink scheduling information includes uplink transmission parameters such as MCS for performing PUSCH transmission, resource block (subcarrier) allocation, timing (uplink subframe), and the like.
  • the radio terminal 20 transmits downlink scheduling change information to the first coordinated base station 10b based on these uplink transmission parameters indicated by the uplink scheduling information received in S310.
  • the first cooperative base station 10b receives downlink scheduling change information from the radio terminal 20 based on these uplink transmission parameters indicated by the uplink scheduling information received in S305.
  • the downlink scheduling information transmitted from the radio terminal 20 to the first cooperative base station 10b may be the one received in S311 as it is, or may be processed within a range that includes information necessary for the first cooperative base station 10b. You may use what you did.
  • the downlink scheduling change information is transmitted from the radio terminal 20 to the first cooperative base station 10b via the radio signal (uplink) in S311. Note that the downlink scheduling information is transmitted via the backhaul in S305 to S306, but S311 is different from these.
  • the downlink scheduling change information from the serving base station 10a to the first cooperative base station 10b can also be interpreted as being relayed by the radio terminal 20.
  • the downlink scheduling change information from the serving base station 10a to the first cooperative base station 10b is received by the radio terminal 20 on the downlink and transmitted on the uplink, thereby realizing relay transmission via the radio terminal 20 Will be.
  • downlink scheduling change information is transmitted from the serving base station 10a to the first coordinated base station 10b via the radio terminal 20.
  • the downlink scheduling change information is transmitted by a radio signal. Since the delay associated with the transmission / reception of the radio signal is minimal, the delay associated with the transmission of the downlink scheduling change information over S310 to S311 is considered to be about several subframes (several milliseconds).
  • the problem caused based on the premise of the non-ideal backhaul is the first embodiment shown in FIG. 5, although the non-ideal backhaul is assumed. Does not occur. More specifically, in FIG. 5, the serving base station 10a transmits the result of rescheduling downlink data in S309 to the coordinated base stations 10b to 10c as downlink scheduling change information in S310 to S312.
  • the downlink scheduling change information transmitted in S310 to S312 reflects the latest downlink quality. Therefore, if this downlink scheduling change information can be notified to the coordinated base stations 10b to 10c in time for the previously determined CoMP transmission timing, CoMP transmission reflecting the latest radio quality can be performed.
  • the radio terminal 20 transmits the downlink scheduling change information received in S310 to the second cooperative base station 10c based on the uplink scheduling information received in S310.
  • the second cooperative base station 10c receives downlink scheduling change information from the radio terminal 20 based on the uplink scheduling information received in S306. Since S312 may be performed in the same manner as S311, detailed description thereof is omitted here.
  • the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c perform CoMP transmission (cooperative transmission) of the downlink data to the wireless terminal 20.
  • the CoMP transmission here reflects the latest downlink quality, as described above.
  • the transmission base station is temporarily determined to be the first cooperative base station 10b in the scheduling of S304, but then the transmission base station is in the second cooperative state in the scheduling of S309.
  • the base station 10c is changed.
  • this change is notified from the serving base station 10a to the coordinated base stations 10b to 10c via the radio terminal 20 by downlink scheduling change information.
  • the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c wirelessly transmit downlink data in cooperation with DPS using the second cooperative base station 10c as a transmission base station. It transmits to the terminal 20.
  • the second cooperative base station 10c which is a transmission base station in S313c, transmits downlink data to the radio terminal 20 based on the downlink scheduling change information received in S312.
  • the serving base station 10a performs blanking (no transmission) to the radio terminal 20 based on its own scheduling result in S309.
  • the first cooperative base station 10b performs blanking for the radio terminal 20 based on the downlink scheduling change information received in S311.
  • wireless terminal 20 receives downlink data from the 2nd cooperation base station 10c.
  • DPS CoMP transmission
  • FIG. 6 shows another example of the processing sequence of the first embodiment.
  • FIG. 5 the scheduling of downlink data has been changed by rescheduling. That is, after the downlink data scheduling is performed once in the first scheduling (S304) in FIG. 5, the downlink data scheduling is changed in the second scheduling (S309) in accordance with a change in downlink quality or the like. It was.
  • FIG. 6 is a diagram showing a processing sequence when downlink data scheduling is not changed by rescheduling.
  • the serving base station 10 a determines the second coordinated base station 10 c as a transmission base station in the scheduling of S ⁇ b> 309. That is, the downlink data scheduling (for example, the transmission base station) is changed in S309 due to a change in downlink radio quality or the like from the time of scheduling in S304.
  • the serving base station 10a determines the first coordinated base station 10c as a transmission base station in the scheduling of S409. That is, it is assumed that scheduling of downlink data (for example, a transmission base station) is not changed in S409 due to a small change in downlink radio quality from the time of scheduling in S404.
  • the serving base station 10a, the first coordinated base station 10b, and the second coordinated base station 10c cooperate with each other by DPS using the first coordinated base station 10c as a transmission base station. Then, the downlink data is transmitted to the wireless terminal 20.
  • the transmission base station is determined to be the first coordinated base station 10b by the scheduling of S404, and thereafter the transmission base station is not changed by the scheduling of S409. Therefore, in S410a to S410c, DPS using the first coordinated base station 10c as a transmission base station is performed according to the determination in the scheduling in S404.
  • DPS CoMP transmission
  • S410a to S410c in FIG. 6 reflects the latest downlink quality, similar to the CoMP transmission (DPS) in S313a to S313c in FIG. Therefore, in the processing sequence shown in FIG. 6 as well, as in FIG. 5, it is considered that DPS, which is one of the CoMP schemes, can be executed appropriately in response to downlink radio quality.
  • the serving base station 10a and the coordinated base stations 10b to 10c perform CoMP transmission reflecting the latest downlink quality. Is possible. Therefore, 1st Embodiment has a remarkable effect which is not in the prior art that the fall of the throughput of the whole radio communications system is controlled.
  • the second embodiment is another example of the embodiment that solves the above-described problem.
  • the serving base station 10a notifies the scheduling of coordinated transmission
  • the notification is coordinated via the radio terminal 20 by a radio signal.
  • the data is transmitted to the base stations 10b to 10c.
  • the second embodiment Since the second embodiment has many points in common with the first embodiment, the second embodiment will be described in detail below with a focus on differences from the first embodiment. It should be noted that in the second embodiment, descriptions overlapping with those in the first embodiment are omitted as appropriate.
  • FIG. 7 is a diagram illustrating an example of a processing sequence according to the second embodiment. Since the premise of the second embodiment is the same as that of the first embodiment, the description is omitted here. However, it should be noted that the second embodiment also assumes a non-ideal backhaul as in the first embodiment.
  • S501 in FIG. 7 may be performed in the same manner as S301 in FIG. 5 according to the first embodiment, a description thereof will be omitted.
  • the serving base station performs scheduling in S502 of FIG. In the scheduling in S502, an uplink transmission parameter is determined.
  • an uplink transmission parameter is determined.
  • the serving base station 10a transmits a signal including downlink data and uplink scheduling information to the first coordinated base station 10b via the backhaul.
  • the first cooperative base station 10b receives a signal including downlink data and uplink scheduling information from the serving base station 10a via the backhaul.
  • S503 of FIG. 7 unlike S305 of FIG. 5 according to the first embodiment, it is not necessary to transmit a transmission base station or downlink scheduling information (transmission base station, downlink transmission parameters, downlink subframe information, etc.). .
  • the transmission of downlink data and uplink scheduling information in S503 may be performed in the same manner as the transmission in S305, and thus detailed description thereof is omitted here. It should be noted that the transmission / reception in S503 is performed via a backhaul (non-ideal backhole), so that a relatively large delay occurs.
  • the serving base station 10a transmits a signal including downlink data and uplink scheduling information to the second cooperative base station 10c via the backhaul.
  • the second cooperative base station 10c receives a signal including downlink data and uplink scheduling information from the serving base station 10a via the backhaul. Since S504 may be performed in the same manner as S503, description thereof is omitted.
  • the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c transmit downlink reference signals to the wireless terminal 20, respectively.
  • the radio terminal 20 transmits CQI indicating the downlink quality measured based on the downlink reference signal in S505a to S505c to the serving base station 10a.
  • the serving base station 10a performs downlink data scheduling in step S501 based on the CQI and the like in step S506.
  • the timing for performing these is the timing corresponding to the latest CQI transmission at the timing indicated by the uplink subframe information included in the uplink scheduling information transmitted and received in S503 to S504.
  • the latest downlink quality is reflected in the scheduling of S507, and downlink scheduling information (described later) transmitted thereafter reflects the latest downlink quality.
  • the serving base station 10a determines the second coordinated base station 10c as the transmission base station in the scheduling of S509.
  • this premise is merely an example for explaining a specific example of processing in the present embodiment. In the following, the description will proceed under this assumption.
  • the serving base station 10a transmits downlink scheduling information and uplink scheduling information to the radio terminal 20 based on the determination in the scheduling of S507.
  • the radio terminal 20 receives downlink scheduling information and uplink scheduling information from the serving base station 10a.
  • the radio terminal 20 transmits the downlink scheduling information received in S508 to the first coordinated base station 10b based on the uplink scheduling information received in S508.
  • the first cooperative base station 10b receives downlink scheduling information from the radio terminal 20 based on the uplink scheduling information received in S503.
  • the radio terminal 20 transmits the downlink scheduling information received in S508 to the second cooperative base station 10c based on the uplink scheduling information received in S508.
  • the second cooperative base station 10c receives downlink scheduling information from the radio terminal 20 based on the uplink scheduling information received in S504.
  • the latest downlink quality is reflected in the downlink scheduling information transmitted and received in S508 to S510.
  • downlink scheduling information is transmitted and received instead of downlink scheduling change information transmitted and received in S310 to S312 of FIG. 5 according to the first embodiment. This is because the downlink transmission scheduling information is transmitted via the back hose in S305 to S306 in FIG. 5 according to the first embodiment, but not transmitted in S503 to S504 in FIG.
  • transmission / reception of downlink scheduling information and uplink scheduling information in S508 may be performed in the same manner as transmission / reception of downlink scheduling change information and uplink scheduling information in S310, detailed description thereof is omitted here. Further, since transmission / reception of downlink scheduling information in S509 to S510 may be performed in the same manner as transmission / reception of downlink scheduling information in S311 to S312, detailed description thereof is omitted here.
  • the serving base station 10a, the first cooperative base station 10b, and the second cooperative base station 10c are cooperatively downloaded by DPS using the second cooperative base station 10c as a transmission base station. Data is transmitted to the wireless terminal 20.
  • the second cooperative base station 10c is set as the transmission base station in S511a to S511c. DPS is performed.
  • the CoMP transmission (DPS) in S511a to S511c in FIG. 7 reflects the latest downlink quality, similar to the CoMP transmission (DPS) in S313a to S313c in FIG. This is because the latest downlink quality is reflected in the downlink scheduling information as described above. Therefore, also in the processing sequence shown in FIG. 7, it is considered that DPS, which is one of the CoMP schemes, can be appropriately executed in response to the downlink radio quality, as in FIG.
  • the second embodiment described above it is possible to solve the above-described problem that occurs when a non-ideal backhaul is assumed. That is, according to the first embodiment, even when a non-ideal backhaul is assumed, the serving base station 10a and the coordinated base stations 10b to 10c perform CoMP transmission reflecting the latest downlink quality. Is possible. Therefore, 1st Embodiment has a remarkable effect which is not in the prior art that the fall of the throughput of the whole radio communications system is controlled.
  • the wireless terminal 20 that receives downlink data by CoMP transmission (cooperative transmission) and the wireless terminal 20 that relays downlink scheduling change information and the like via a wireless link are the same wireless terminal 20. is there.
  • the wireless terminal 20 receives downlink data by CoMP transmission in S313a to S313c, but the same wireless terminal 20 relays downlink scheduling change information via a wireless link in S310 to S312. Sending.
  • the wireless terminal 20 that receives downlink data by CoMP transmission and the wireless terminal 20 that relays downlink scheduling change information and the like via a wireless link are different wireless terminals 20. Note that it does not matter.
  • the radio terminal 20 transmits downlink scheduling change information transmitted and received between the radio base stations 10 in order to perform CoMP transmission. Relay transmission via wireless link.
  • the present invention is not based on the assumption that CoMP transmission (cooperative transmission) is performed, and the wireless terminal 20 can relay and transmit arbitrary information transmitted and received between the wireless base stations 10 via the wireless link. Is.
  • the radio terminal 20 can relay and transmit information including the scheduling result via a radio link.
  • the radio terminal 20 when a plurality of radio base stations 10 perform arbitrary processing in cooperation, the radio terminal 20 relays any information transmitted / received between the plurality of radio base stations 10 via a radio link. It is possible to send.
  • the wireless terminal 20 relays and transmits information transmitted and received between the wireless base stations 10.
  • the present invention may be such that a device other than the wireless terminal 20 performs relay transmission.
  • a wireless relay station wireless relay device
  • the wireless relay station 10 can relay and transmit information transmitted and received between the wireless base stations 10.
  • the third radio base station 10 can relay and transmit information transmitted and received between the first radio base station 10 and the second radio base station 10.
  • the non-ideal backhaul is between the first radio base station 10 and the second radio base station 10, but between the first radio base station 10 and the third radio base station 10 and third
  • the third wireless base station 10 performs relay transmission, so that the same effects as those of the above embodiments are obtained. It is possible to play.
  • each radio terminal 20 calculates the CQI for the downlink reference signal from each radio base station 10
  • the radio terminal 20 similarly determines downlink scheduling information for downlink data based on this, and notifies each radio base station 10 of the same. Good.
  • each radio base station 10 notifies the radio terminal 20 of the load information, so that the radio terminal 20 can determine downlink scheduling data while considering the load of each radio base station 20.
  • the invention is applied to a non-ideal backhaul, but the present invention is not limited to this. It is also one of the embodiments that the present invention is implemented as a preparation for becoming a non-ideal backhaul in the future due to the secular change or the like of the current ideal backhaul. Needless to say.
  • the wireless communication system 1 includes a wireless base station 10 and a wireless terminal 20.
  • the wireless communication system 1 includes a wireless base station 10 and a wireless terminal 20.
  • three radio base stations 10a to 10c and seven radio terminals 20a to 20g are shown, but it goes without saying that this is only an example.
  • Each radio base station 10 forms a cell.
  • Each wireless terminal 20 exists in a cell, in other words, is under the control (under management) of each wireless base station 10.
  • the radio terminals 20a to 20c are under the radio base station 10a
  • the radio terminals 20d to 20e are under the radio base station 10b
  • the radio terminals 20f to 20g are under the radio base station 10c. is there.
  • the wireless base station 10 is connected to the network device 3 via a wired connection, and the network device 3 is connected to the network 2 via a wired connection.
  • the radio base station 10 is provided so as to be able to transmit / receive data and control information to / from other radio base stations 10 via the network device 3 and the network 2.
  • the backhaul which is a network connecting wireless base stations, is assumed to be non-ideal. However, some of them may be ideal.
  • the radio base station 10 may separate the radio communication function with the radio terminal 20 and the digital signal processing and control function to be a separate device.
  • a device having a wireless communication function is referred to as RRH (Remote Radio Head)
  • BBU Base Band Unit
  • the RRH may be installed overhanging from the BBU, and may be wired with an optical fiber between them.
  • the radio base station 10 is a radio of various scales other than small radio base stations 10 (including a micro radio base station 10, a femto radio base station 10 and the like) such as a macro radio base station 10 and a pico radio base station 10. It may be the base station 10.
  • the relay station transmission / reception with the wireless terminal 20 and its control
  • the wireless base station 10 of the present application It is good.
  • the wireless terminal 20 communicates with the wireless base station 10 by wireless communication.
  • the wireless terminal 20 may be a wireless terminal 20 such as a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a personal computer (Personal Computer), various devices or devices (such as sensor devices) having a wireless communication function. Further, when a relay station that relays radio communication between the radio base station 10 and the radio terminal 20 is used, the relay station (transmission / reception with the radio base station 10 and its control) is also included in the radio terminal 20 of this paper. It is good.
  • the network device 3 includes, for example, a communication unit and a control unit, and these components are connected so that signals and data can be input and output in one direction or in both directions.
  • the network device 3 is realized by a gateway, for example.
  • the communication unit is realized by an interface circuit
  • the control unit is realized by a processor and a memory.
  • each component of the radio base station 10 and the radio terminal 20 is not limited to the mode of each embodiment, and all or a part thereof depends on various loads, usage conditions, and the like. Thus, it can be configured to be functionally or physically distributed and integrated in arbitrary units.
  • the memory may be connected as an external device of the radio base station 10 and the radio terminal 20 via a network or a cable.
  • FIG. 9 is a functional block diagram showing an example of the configuration of the radio base station 10.
  • the radio base station 10 includes, for example, a radio transmission unit 11, a radio reception unit 12, a control unit 13, a storage unit 14, and a communication unit 15. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
  • the wireless transmission unit 11 and the wireless reception unit 12 are collectively referred to as a wireless communication unit 16.
  • the wireless transmission unit 11 transmits a data signal and a control signal by wireless communication via an antenna.
  • the antenna may be common for transmission and reception.
  • the radio transmission unit 11 transmits a radio signal (downlink radio signal) to the radio terminal 20.
  • the radio signal transmitted by the radio transmission unit 11 can include arbitrary user data and control information for the radio terminal 20 (encoding and modulation are performed).
  • radio signal transmitted by the radio transmission unit 11 include radio signals (arrows in the figure) transmitted from the radio base station 10 to the radio terminal 20 in FIGS. 5, 6, and 7. Is mentioned.
  • the radio signal transmitted by the radio transmission unit 11 is not limited to these, and includes any radio signal transmitted from each radio base station 10 to the radio terminal 20 in each of the above embodiments and modifications.
  • the wireless receiving unit 12 receives a data signal and a control signal by wireless communication via an antenna.
  • the radio reception unit 12 receives a radio signal (uplink radio signal) from the radio terminal 20.
  • the radio signal received by the radio reception unit 12 can include arbitrary user data and control information (encoded or modulated) transmitted by the radio terminal 20.
  • radio signal received by the radio receiving unit 12 include radio signals (arrows in the figure) received by the radio base station 10 from the radio terminal 20 in FIGS. 5, 6, and 7. It is done.
  • the signals received by the wireless reception unit 12 are not limited to these, and include any wireless signal that each wireless base station 10 receives from the wireless terminal 20 in each of the above embodiments and modifications.
  • the control unit 13 outputs data and control information to be transmitted to the wireless terminal 20 to the wireless transmission unit 11.
  • the control unit 13 inputs data and control information received from the wireless terminal 20 from the wireless reception unit 12.
  • the control unit 13 inputs and outputs data, control information, programs, and the like with the storage unit 14 described later.
  • the control unit 13 inputs / outputs data and control information transmitted / received to / from the other radio base station 10 and the like with the communication unit 15 described later. In addition to these, the control unit 13 performs various controls in the radio base station 10.
  • processing controlled by the control unit 13 include control on signals (arrows in the figure) transmitted and received by each radio base station 10 in FIGS. 5, 6, and 7, and each radio base station 10 The control for each process (rectangle in the figure) being performed is given.
  • the process which the control part 13 controls is not restricted to these, but includes the control regarding all the processes which each radio base station 10 performs by said each embodiment and modification.
  • the storage unit 14 stores various information such as data, control information, and programs.
  • the various information stored in the storage unit 14 includes all information that can be stored in each radio base station 10 in each of the above embodiments and modifications.
  • the communication unit 15 transmits / receives data and control information to / from another wireless base station 10 or the like via a wired signal or the like (which may be a wireless signal).
  • a wired signal or the like which may be a wireless signal.
  • Specific examples of the wired signal transmitted and received by the communication unit 15 include each wired signal transmitted and received by each wireless base station 10 with respect to the other wireless base station 10 in FIG. 5, FIG. 6, and FIG. Middle arrow).
  • the wired signals transmitted and received by the communication unit 15 are not limited to these, and include all wired signals transmitted and received by each wireless base station 10 from other wireless base stations 10 and the like in the above-described embodiments and modifications.
  • the radio base station 10 may transmit and receive radio signals to / from radio communication devices other than the radio terminal 20 (for example, other radio base stations 10 and relay stations) via the radio transmission unit 11 and the radio reception unit 12. .
  • FIG. 10 is a functional block diagram showing an example of the configuration of the wireless terminal 20.
  • the wireless terminal 20 includes, for example, a wireless transmission unit 21, a wireless reception unit 22, a control unit 23, and a storage unit 24. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
  • the wireless transmission unit 21 and the wireless reception unit 22 are collectively referred to as a wireless communication unit 25.
  • the wireless transmission unit 21 transmits a data signal and a control signal by wireless communication via an antenna.
  • the antenna may be common for transmission and reception.
  • the radio transmission unit 21 transmits a radio signal (uplink radio signal) to each radio base station 10.
  • the radio signal transmitted by the radio transmission unit 21 can include arbitrary user data, control information, and the like (encoded and modulated) for each radio base station 10.
  • radio signal transmitted by the radio transmission unit 21 include radio signals (arrows in the figure) transmitted from the radio terminal 20 to the radio base stations 10 in FIGS. 5, 6, and 7. Is mentioned.
  • the radio signal transmitted by the radio transmission unit 21 is not limited to these, and includes any radio signal transmitted from the radio terminal 20 to each radio base station 10 in each of the above embodiments and modifications.
  • the wireless receiving unit 22 receives data signals and control signals by wireless communication via an antenna.
  • the radio reception unit 22 receives a radio signal (downlink radio signal) from each radio base station 10.
  • the radio signal received by the radio reception unit 22 can include arbitrary user data, control information, and the like (encoded or modulated) transmitted by each radio base station 10.
  • radio signals received by the radio receiver 22 include radio signals (arrows in the figure) received by the radio terminal 20 from the radio base station 10 in FIGS. 5, 6, and 7. .
  • the signal received by the wireless reception unit 22 is not limited to these, and includes any wireless signal that the wireless terminal 20 receives from each wireless base station 10 in each of the above embodiments and modifications.
  • the control unit 23 outputs data and control information to be transmitted to each radio base station 10 to the radio transmission unit 21.
  • the control unit 23 inputs data and control information received from each radio base station 10 from the radio reception unit 22.
  • the control unit 23 inputs and outputs data, control information, programs, and the like with the storage unit 24 described later. In addition to these, the control unit 23 performs various controls in the wireless terminal 20.
  • control unit 23 Specific examples of processing controlled by the control unit 23 include control for each signal (arrow in the figure) transmitted and received by the wireless terminal 20 in FIGS. 5, 6, and 7, and the wireless terminal 20 performs. Control for each process (rectangle in the figure) is mentioned. The process which the control part 23 controls is not restricted to these, but includes the control regarding all the processes which the radio
  • the storage unit 24 stores various information such as data, control information, and programs.
  • the various information stored in the storage unit 24 includes all information that can be stored in the wireless terminal 20 in each of the above-described embodiments and modifications.
  • the wireless terminal 20 may transmit and receive wireless signals to and from wireless communication devices other than the wireless base station 10 via the wireless transmission unit 21 and the wireless reception unit 22.
  • FIG. 11 is a diagram illustrating an example of a hardware configuration of the radio base station 10.
  • the radio base station 10 includes, as hardware components, an RF (Radio Frequency) circuit 112 including an antenna 111, a processor 113, a memory 114, and a network IF (Interface) 115, for example. Have. These components are connected so that various signals and data can be input and output via a bus.
  • RF Radio Frequency
  • the processor 113 is, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). In the present application, the processor 113 may be realized by a digital electronic circuit. Examples of digital electronic circuits include ASIC (Application Specific Integrated Circuit), FPGA (Field-Programming Gate Array), LSI (Large Scale Integration), and the like.
  • ASIC Application Specific Integrated Circuit
  • FPGA Field-Programming Gate Array
  • LSI Large Scale Integration
  • the memory 114 includes at least one of RAM (Random Access Memory) such as SDRAM (Synchronous Dynamic Random Access Memory), ROM (Read Only Memory), and flash memory, and stores programs, control information, and data.
  • RAM Random Access Memory
  • SDRAM Serial Dynamic Random Access Memory
  • ROM Read Only Memory
  • flash memory stores programs, control information, and data.
  • the radio base station may include an auxiliary storage device (such as a hard disk) not shown.
  • the wireless transmission unit 11 and the wireless reception unit 12 are realized by the RF circuit 112, or the antenna 111 and the RF circuit 112, for example.
  • the control unit 13 is realized by, for example, the processor 113, the memory 114, a digital electronic circuit (not shown), and the like.
  • the storage unit 14 is realized by the memory 114, for example.
  • the communication unit 15 is realized by the network IF 115, for example.
  • FIG. 12 is a diagram illustrating an example of a hardware configuration of the wireless terminal 20.
  • the wireless terminal 20 includes, as hardware components, an RF (Radio Frequency) circuit 122 including an antenna 121, a processor 123, and a memory 124, for example. These components are connected so that various signals and data can be input and output via a bus.
  • RF Radio Frequency
  • the processor 123 is, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). In the present application, the processor 123 may be realized by a digital electronic circuit. Examples of digital electronic circuits include ASIC (Application Specific Integrated Circuit), FPGA (Field-Programming Gate Array), LSI (Large Scale Integration), and the like.
  • ASIC Application Specific Integrated Circuit
  • FPGA Field-Programming Gate Array
  • LSI Large Scale Integration
  • the memory 124 includes at least one of RAM (Random Access Memory) such as SDRAM (Synchronous Dynamic Random Access Memory), ROM (Read Only Memory), and flash memory, and stores programs, control information, and data.
  • RAM Random Access Memory
  • SDRAM Serial Dynamic Random Access Memory
  • ROM Read Only Memory
  • flash memory stores programs, control information, and data.
  • the wireless transmission unit 21 and the wireless reception unit 22 are realized by the RF circuit 122, the antenna 121, and the RF circuit 122, for example.
  • the control unit 23 is realized by, for example, the processor 123, the memory 124, a digital electronic circuit (not shown), and the like.
  • the storage unit 24 is realized by the memory 124, for example.
  • wireless communication system 1 wireless communication system 2 network 3 network device 10 wireless base station 20 wireless terminal

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

Abstract

L'invention a pour objectif de résoudre les problèmes liés à une CoMP prédite sur un accès radio terrestre sans fil peu sûr. Le procédé de radiocommunication décrit ici est utilisé pour exécuter une transmission coordonnée dans laquelle des première et seconde stations de base radio sont coordonnées pour transmettre un signal radio à un premier d'un ou plusieurs terminaux radio. Selon ce procédé de radiocommunication, la première station de base radio transmet, à un second terminal radio qui est l'un du ou des terminaux radio, des informations de programmation de liaison descendante qui doivent être utilisées pour exécuter la transmission coordonnée, et le second terminal radio transmet les informations de programmation de liaison descendante à la seconde station de base radio.
PCT/JP2013/005599 2013-09-20 2013-09-20 Procédé de radiocommunication, système de radiocommunication, station de base radio, et terminal radio WO2015040659A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018033071A1 (fr) * 2016-08-19 2018-02-22 中兴通讯股份有限公司 Procédé et appareil de commande collaborative parmi des points d'accès sans fil
WO2023153354A1 (fr) * 2022-02-14 2023-08-17 Kddi株式会社 Nœud de réseau, procédé de commande et programme pour améliorer l'efficacité de communications à l'aide d'une pluralité d'ondes de propagation

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JP2008278265A (ja) * 2007-04-27 2008-11-13 Ntt Docomo Inc 移動通信システム、基地局装置、移動局装置、および、スケジューリング方法
WO2011148588A1 (fr) * 2010-05-28 2011-12-01 パナソニック株式会社 Station de base, système de communication mobile, et procédé de suppression du brouillage
WO2012175360A1 (fr) * 2011-06-20 2012-12-27 Ntt Docomo, Inc. Appareil et procédé de détermination d'une grappe de stations de base

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
JP2008278265A (ja) * 2007-04-27 2008-11-13 Ntt Docomo Inc 移動通信システム、基地局装置、移動局装置、および、スケジューリング方法
WO2011148588A1 (fr) * 2010-05-28 2011-12-01 パナソニック株式会社 Station de base, système de communication mobile, et procédé de suppression du brouillage
WO2012175360A1 (fr) * 2011-06-20 2012-12-27 Ntt Docomo, Inc. Appareil et procédé de détermination d'une grappe de stations de base

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018033071A1 (fr) * 2016-08-19 2018-02-22 中兴通讯股份有限公司 Procédé et appareil de commande collaborative parmi des points d'accès sans fil
WO2023153354A1 (fr) * 2022-02-14 2023-08-17 Kddi株式会社 Nœud de réseau, procédé de commande et programme pour améliorer l'efficacité de communications à l'aide d'une pluralité d'ondes de propagation

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