JP2015188268A - Receiver, transmitter, and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver, transmitter, and radio communication method capable of utilizing non-orthogonal multiple access while suppressing a cost rise and processing delay.SOLUTION: A mobile station 200A comprises a physical channel separation part 210 and a data demodulation/decoding part 220. A radio resource block allocated to a non-orthogonal signal is defined by a frequency region, time region, and non-orthogonal multiplex region. The non-orthogonal multiplex region has a plurality of levels depending on the number of interference cancellations by the data demodulation/decoding part 220. An interference canceler of the mobile station 200A cancels a non-orthogonal signal to which a radio resource block whose level is lower than that of the mobile station 200A is allocated.

Description

  The present invention relates to a receiving apparatus, a transmitting apparatus, and a wireless communication method adapted to non-orthogonal multiple access.

  In a mobile communication system such as Long Term Evolution (LTE) standardized in 3GPP, orthogonal multi-access using orthogonal signals in which a plurality of signals do not interfere with each other is performed between a base station and a user terminal (mobile station). Widely used. On the other hand, non-orthogonal multiple access using non-orthogonal signals has been proposed in order to increase the capacity of a mobile communication system (see, for example, Non-Patent Document 1).

  Non-orthogonal multi-access is premised on signal separation (interference canceller) by nonlinear signal processing. For example, in the case of downlink, the base station transmits non-orthogonal signals simultaneously to a plurality of user terminals. Each user terminal demodulates the received non-orthogonal signal after removing a signal to a user terminal (at the cell edge) having a path loss larger than that of the user terminal by signal processing.

D. Tse and P. Viswanath, “Fundamentals of Wireless Communication”, Cambridge University Press, 2005, Internet <http://www.eecs.berkeley.edu/~dtse/book.html>

  As described above, in the case of non-orthogonal multi-access, each user terminal, that is, a mobile station, needs to demodulate after removing a signal to a mobile station having a path loss larger than that of its own station by signal processing. For this reason, the processing load on the mobile station is high, and the problem of an increase in cost and processing delay of the mobile station may occur. In order to solve such a problem, introduction of hybrid orthogonal / non-orthogonal multi-access using both orthogonal multi-access and non-orthogonal multi-access is conceivable. Thereby, it is considered that the problem of the cost increase and processing delay of the mobile station can be suppressed to some extent.

  However, from the viewpoint of implementation, it is preferable that each mobile station can recognize the state of the mobile station multiplexed as non-orthogonal multi-access in order to further reduce cost and processing delay.

  Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a receiving device, a transmitting device, and a wireless communication method that can use non-orthogonal multi-access while suppressing cost increase and processing delay. And

  The first feature of the present invention is that a radio signal receiving unit (physical channel separation unit 210) that receives a radio signal including a plurality of non-orthogonal signals that are not orthogonal to each other, and a plurality of non-signals received by the radio signal receiving unit. An interference cancellation unit (data demodulation / decoding unit 220) that extracts a non-orthogonal signal addressed to the receiving device by demodulating and canceling a radio signal addressed to the other receiving device from the orthogonal signals, and the interference canceling unit The radio resource block allocated to the non-orthogonal signal includes a frequency domain, a time domain, and a non-orthogonal multiplex. The non-orthogonal multiplex region has a plurality of levels according to the number of interference cancellations by the interference cancellation unit, and the interference cancellation unit Le is summarized in that a receiver for canceling the non-orthogonal signal radio resource block is allocated a lower level than the receiving device (e.g., mobile station 200A).

  A second feature of the present invention is that a radio signal transmission unit (hybrid orthogonal / non-orthogonal multiplexing unit) transmits a radio signal including a plurality of non-orthogonal signals that are not orthogonal to each other to a plurality of receiving devices located in the cell. 130 and a physical channel multiplexing unit 160), and an allocation unit (encoding / data modulation unit 110) that allocates radio resource blocks to the non-orthogonal signals, the allocation unit including a frequency domain, a time domain, and a reception The gist of the present invention is that it is a transmission apparatus (base station 100) that assigns radio resource blocks defined by non-orthogonal multiplex regions having a plurality of levels according to the number of interference cancellations in the apparatus to the non-orthogonal signals.

  The third feature of the present invention is that the communication device receives a radio signal including a plurality of non-orthogonal signals that are not orthogonal to each other, and the communication device receives another one of the received non-orthogonal signals. A step of extracting a non-orthogonal signal addressed to the receiving device by demodulating and canceling a radio signal addressed to the receiving device, and a step of demodulating the signal addressed to the receiving device extracted in the extracting step. The radio resource block allocated to the non-orthogonal signal is defined by a frequency region, a time region, and a non-orthogonal multiplex region, and the non-orthogonal multiplex region has a plurality of levels according to the number of interference cancellations in the communication device. And the step of canceling the interference allocates a radio resource block whose level is lower than that of its own device. And summarized in that a is a non-orthogonal signal radio communication method to cancel.

  According to the characteristics of the present invention, it is possible to provide a receiving device, a transmitting device, and a wireless communication method that can use non-orthogonal multi-access while suppressing cost increase and processing delay.

1 is an overall schematic configuration diagram of a mobile communication system 1 according to an embodiment of the present invention. It is a figure which shows the radio resource allocation image of orthogonal multi-access, non-orthogonal multi-access, and hybrid orthogonal / non-orthogonal multi-access. FIG. 4 is a functional block configuration diagram of a transmission unit of the base station 100 according to the embodiment of the present invention. FIG. 4 is a functional block configuration diagram of a receiving unit of a mobile station 200A according to the embodiment of the present invention. FIG. 4 is a diagram illustrating an example of scheduling of a mobile station to a non-orthogonal signal in the base station 100 according to the embodiment of the present invention. It is explanatory drawing of the example 1 of the allocation of the radio | wireless resource block which concerns on embodiment of this invention. It is explanatory drawing of the example 2 of the allocation of the radio | wireless resource block which concerns on embodiment of this invention. It is explanatory drawing of the example 3 of the allocation of the radio | wireless resource block which concerns on embodiment of this invention. It is explanatory drawing of the example 4 of the allocation of the radio | wireless resource block which concerns on embodiment of this invention. It is explanatory drawing of the example 5 of the allocation of the radio | wireless resource block which concerns on embodiment of this invention. It is explanatory drawing of the example of allocation of the radio | wireless resource block which concerns on the example of a change of this invention.

  Next, an embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(1) Configuration of Mobile Communication System FIG. 1 is an overall schematic configuration diagram of a mobile communication system 1 according to the present embodiment. As shown in FIG. 1, the mobile communication system 1 includes a base station 100 and mobile stations 200A and 200B.

  Base station 100 transmits a radio signal to mobile stations 200A and 200B, specifically, into cell C1. The base station 100 receives radio signals from the mobile stations 200A and 200B. In the present embodiment, the base station 100 constitutes a transmission device, and the mobile stations 200A and 200B constitute a reception device.

  The mobile station 200A is located in the cell edge of the cell C1 that is located in the cell C1 but has a large path loss of the radio signal from the base station 100. Mobile station 200B is located in the center of cell C1. For this reason, the path loss of the radio signal from the base station 100 is smaller than the path loss in the mobile station 200A.

  In the present embodiment, the base station 100 and the mobile stations 200A and 200B are configured such that the mobile station 200A is located in the cell C1 with a radio signal including a plurality of orthogonal signals orthogonal to each other and a plurality of non-orthogonal signals not orthogonal to each other. , Send to 200B. That is, in the mobile communication system 1, the orthogonal multi-access that realizes simultaneous communication with a plurality of mobile stations using orthogonal signals and the non-orthogonal multi-access that realizes simultaneous communication with a plurality of mobile stations using non-orthogonal signals. Access is used together (hereinafter referred to as hybrid orthogonal / non-orthogonal multiple access).

  FIGS. 2A to 2C show radio resource allocation images of orthogonal multi-access, non-orthogonal multi-access, and hybrid orthogonal / non-orthogonal multi-access. As shown in FIG. 2A, in orthogonal multi-access, radio resources allocated to each mobile station (user) do not overlap in the frequency domain / time domain / space domain. For this reason, in the orthogonal multi-access, in principle, it is not necessary to remove interference caused by radio resources allocated to other mobile stations. Orthogonal multiple access is also used in Long Term Evolution (LTE) standardized by 3GPP.

  As shown in FIG. 2B, in non-orthogonal multiple access, radio resources allocated to each mobile station overlap in the band. For this reason, the mobile station needs to remove all multi-access interference by signal processing. For specific signal processing, the technique described in Non-Patent Document 1 described above can be used.

  As shown in FIG. 2 (c), in hybrid orthogonal / non-orthogonal multiple access, radio resources allocated to each mobile station partially overlap in the band. For this reason, the mobile station only needs to remove multi-access interference equal to or less than the specified number in accordance with the number of multiplexed radio resources.

  In this embodiment, by introducing hybrid orthogonal / non-orthogonal multi-access, the signal processing load accompanying the removal of multi-access interference is reduced, and a radio that can recognize the number of multi-access interference to be removed by the mobile station An interface is defined.

(2) Functional Block Configuration Next, a functional block configuration of the mobile communication system 1 will be described. FIG. 3 is a functional block configuration diagram of the transmission unit of the base station 100. FIG. 4 is a functional block configuration diagram of the receiving unit of the mobile station 200A.

(2.1) Base station 100
As shown in FIG. 3, the transmission unit of the base station 100 includes an encoding / data modulation unit 110, a base station scheduler 120, a hybrid orthogonal / non-orthogonal multiplexing unit 130, a control signal generation unit 140, a control signal resource allocation unit 150, A physical channel multiplexing unit 160 is provided.

  The encoding / data modulation unit 110 executes transmission data division, channel coding / data modulation, transmission power setting, and resource block allocation for each predetermined user (user k). In particular, in the present embodiment, encoding / data modulation section 110 allocates radio resource blocks to orthogonal signals and non-orthogonal signals included in radio signals transmitted toward mobile stations 200A and 200B.

  The base station scheduler 120 is based on the feedback of Circuit State Information (CSI) from the mobile stations 200A and 200B and the path loss between the base station 100 and the mobile stations 200A and 200B. Control the non-orthogonal multiplexing unit 130 and the control signal generation unit 140.

  In particular, in the present embodiment, the base station scheduler 120 increases the difference in path loss based on the path loss to each of a plurality of mobile stations (for example, mobile stations 200A and 200B) of signals multiplexed as non-orthogonal signals. Thus, a signal multiplexed as a non-orthogonal signal is scheduled to the plurality of mobile stations.

  FIG. 5 shows an example of scheduling of mobile stations to non-orthogonal signals in the base station 100. In the example shown in FIG. 5, a non-orthogonal signal in which a maximum of four users (mobile stations) are multiplexed is used. As shown in FIG. 5, in the non-orthogonal signal, a plurality of signals are not orthogonal, that is, the same radio resource block is allocated in the frequency domain or the time domain.

  In this embodiment, a signal addressed to a mobile station having a small path loss is sequentially multiplexed as a non-orthogonal signal from a signal addressed to a mobile station having a small path loss. A signal addressed to a mobile station with a small path loss may have a small ratio in the vertical axis (transmission power) direction of FIG. 5 because transmission power for securing a desired SNR may be small. On the other hand, a signal addressed to a mobile station having a large path loss has a large transmission power for securing a desired SNR, and therefore, the ratio of the signal in the vertical axis (transmission power) direction in FIG. 5 is large.

  When such a non-orthogonal signal is used, for example, a user (mobile station) having the second smallest path loss needs to remove interference from signals assigned to two mobile stations having a larger path loss than the user. Yes (see explanation in the figure).

  In the example shown in FIG. 5, different radio resource blocks are allocated in the frequency domain and the time domain, that is, orthogonal signals in which a plurality of signals are orthogonal to each other are also used. Since no interference occurs, the mobile station does not need to cancel the interference.

  The hybrid orthogonal / non-orthogonal multiplexing unit 130 multiplexes orthogonal signals and non-orthogonal signals. Specifically, the hybrid orthogonal / non-orthogonal multiplexing unit 130 multiplexes signals (radio resource blocks) output from the plurality of encoding / data modulation units 110 based on control from the base station scheduler 120. As a result, a multiplexed signal is generated as shown in FIG.

  The control signal generation unit 140 generates various control signals that are notified to the mobile stations 200A and 200B. In particular, in the present embodiment, the maximum number of signals multiplexed as non-orthogonal signals is known (for example, 4 multiplexing) in the base station 100 and the mobile stations 200A and 200B. The control signal generator 140 generates a control signal necessary for the mobile station to demodulate and cancel a radio signal addressed to another mobile station (another device).

  For example, the control signal generation unit 140 may generate a signal including control information or a reference signal as described below in order for the mobile station to demodulate and cancel a radio signal addressed to another mobile station (another device). it can.

(A) Information (including 0 or 1) indicating the number of multi-access interference to be removed by the user (mobile station)
(B) Information indicating the status (allocated radio resource block, modulation scheme, channel coding rate, etc.) of other users necessary for the user (mobile station) to eliminate multi-access interference (c) Coherent in the user (mobile station) Reference signal required for demodulation (d) Information required for radio resource block allocation for hybrid orthogonal / non-orthogonal multi-access (transport block, radio resource block definition, transmission power control, feedback control signal, etc.)
The control signal generation unit 140 may generate a control signal obtained by combining any one of (a) to (d) described above or a plurality thereof. The control signal generation unit 140 transmits the generated control signal to the mobile stations 200A and 200B via the control signal resource allocation unit 150 and the physical channel multiplexing unit 160.

  Control signal resource allocation section 150 allocates a radio resource block to the control signal output from control signal generation section 140.

  The physical channel multiplexing unit 160 multiplexes the baseband signal output from the hybrid orthogonal / non-orthogonal multiplexing unit 130 and the control signal output from the control signal resource allocation unit 150 onto the physical channel. The signal output from the physical channel multiplexing unit 160 is subjected to IFFT and a cyclic prefix (CP) is added and transmitted from the transmission antenna to the mobile stations 200A and 200B. In the present embodiment, a radio signal for transmitting an orthogonal signal and a non-orthogonal signal to a plurality of mobile stations (receiving devices) located in the cell C1 by the hybrid orthogonal / non-orthogonal multiplexing unit 130 and the physical channel multiplexing unit 160. A transmission unit is configured.

(2.2) Mobile station 200A
As illustrated in FIG. 4, the mobile station 200A includes a physical channel separation unit 210, a data demodulation / decoding unit 220, a target user control signal detection unit 230, and an interference user control signal detection unit 240. Note that the mobile station 200B also has the same functional block configuration as the mobile station 200A.

  The physical channel separation unit 210 receives a radio signal transmitted from the base station 100 and separates a physical channel included in the radio signal. As described above, the radio signal received by the physical channel separation unit 210 is a radio signal transmitted from the base station 100 (one transmitting apparatus), and is an orthogonal signal that is orthogonal to each other and a non-orthogonal signal that is not orthogonal to each other. It is included. The separated physical channel is output to the data demodulation / decoding unit 220, the target user control signal detection unit 230, and the interference user control signal detection unit 240. In the present embodiment, the physical channel separation unit 210 constitutes a radio signal reception unit.

  A plurality of data demodulation / decoding units 220 are provided. Specifically, the data demodulating / decoding unit 220 is provided for the interference user and the target user according to the number of signals (users) multiplexed as non-orthogonal signals. In this embodiment, since up to four users are multiplexed, it is preferable that four data demodulation / decoding units 220 are also provided.

  The data demodulation / decoding unit 220 performs radio resource block extraction, interference canceller, channel estimation, demodulation decoding, and decoding data decoding.

  In particular, in the present embodiment, the interference canceller of the data demodulation / decoding unit 220 uses a quadrature signal (for example, the control information and the reference signal described above) included in the received radio signal, from among a plurality of non-orthogonal signals. A non-orthogonal signal addressed to the mobile station 200A is extracted by demodulating and canceling a radio signal addressed to another mobile station (receiving device).

  Specifically, the interference canceller extracts a signal addressed to itself from the received non-orthogonal signal by signal separation by predetermined signal processing, and cancels interference due to a signal addressed to another receiving device. The interference canceller has a known maximum number of non-orthogonal signals to be multiplexed (in this embodiment, four multiplexing), and therefore the radio addressed to other receiving apparatuses is within a range not exceeding the known maximum number of non-orthogonal signals. Demodulate and cancel the signal. A method for canceling interference will be described later.

  Data demodulation / decoding section 220 demodulates the signal destined for mobile station 200A included in the orthogonal signal and the signal destined for mobile station 200A extracted by the interference canceller.

  The target user control signal detection unit 230 detects a control signal addressed to the target user, that is, the own apparatus (mobile station 200A). The target user control signal detection unit 230 provides the detected control signal to the data demodulation / decoding unit 220 (for the target user). Any one or combination of (a) to (d) as described above is used as the control signal.

  The interference user control signal detection unit 240 detects a control signal addressed to an interference user, that is, another device (for example, the mobile station 200B). Similar to the target user control signal detection unit 230, the interference user control signal detection unit 240 provides the detected control signal to the data demodulation / decoding unit 220 (for interference users).

  Here, signal processing in the interference canceller of the data demodulation / decoding unit 220 will be briefly described. First, as shown in FIG. 1, when the mobile station 200A is located at the cell edge of the cell C1, the interference canceller cannot remove the signal of the mobile station 200B located in the center of the cell C1, so that data demodulation / decoding is performed. The unit 220 performs demodulation / decoding as it is. Specifically, the signal processing in the user 1 can be described based on the following calculation formula.

Here, the user 1 shows a mobile station 200A located at the cell edge of the cell C1, and the user 2 shows a mobile station 200B located at the center in the cell C1. P ₁ and P ₂ are transmission powers of user 1 and user 2. h ₁ and h ₂ are channel gains of user 1 and user 2.

Thus, when the mobile station (user 1) is located at the cell edge, the received signal (R ₁ ) includes interference with the mobile station (user 2) located in the center of the cell. And since SNR is bad, the interference from the user 2 cannot be removed. Therefore, the user 1 performs demodulation / decoding as it is without removing the signal of the user 2.

  On the other hand, the signal processing in the user 2 can be described based on the following calculation formula.

As described above, when the mobile station (user 2) is located at the center of the cell, the received signal (R ₂ ) includes interference with the mobile station (user 1) located at the cell edge. Since the SNR is good, the signal of the user 1 is once removed by decoding, and after the signal is removed, the signal of the user 2 is demodulated / decoded.

  Such signal processing is the same as the method described in Non-Patent Document 1 described above.

(3) Example of Radio Resource Block Allocation Next, an example of radio resource block allocation will be described. Specifically, radio resource block allocation examples 1 to 4 will be described with reference to FIGS.

(3.1) Allocation example 1
FIG. 6 is an explanatory diagram of an allocation example 1 of radio resource blocks. In this embodiment, in addition to the conventional radio resource block definition such as frequency / time domain, a new radio resource domain (level) for non-orthogonal multiplexing is defined (hereinafter referred to as non-orthogonal multiplexing domain). That is, the radio resource block allocated to the non-orthogonal signal is defined by the frequency domain, the time domain, and the non-orthogonal multiplex domain.

  The non-orthogonal multiplex region has a plurality of levels according to the number of interference cancellations (or the order of interference cancellation) by the data demodulation / decoding unit 220 (interference canceller). That is, the number of interference cancellations is determined by the path loss between the base station 100 and the mobile stations 200A and 200B, and a higher level radio resource block is allocated as the path loss is smaller. That is, the encoding / data modulation unit 110 (allocation unit) of the base station 100 has a plurality of levels according to the frequency domain, the time domain, and the number of interference cancellations (such as path loss up to the mobile stations 200A and 200B). A radio resource block defined by a non-orthogonal multiplex region is assigned to a non-orthogonal signal.

  The mobile stations 200A and 200B (own users) are assigned to lower-level mobile stations (interferences) in the non-orthogonal multiplex region with respect to radio resource blocks in the frequency / time domain to which the own devices are assigned. (The arrow in the figure indicates the radio resource block allocated to the lower level non-orthogonal signal that the higher level mobile station must remove). That is, the interference cancellers of the mobile stations 200A and 200B cancel a non-orthogonal signal to which a radio resource block whose level is lower than that of its own device is assigned.

  By defining the non-orthogonal multiplexing region in this way, the mobile station (user) and radio resource block that are subject to interference cancellation are automatically determined uniquely by the assigned radio resource block.

(3.2) Allocation example 2
FIG. 7 is an explanatory diagram of an allocation example 2 of radio resource blocks. In allocation example 2, hierarchical radio resource blocks are defined. Specifically, the size (frequency / time domain) of the lower level radio resource block is defined to be larger than the size (frequency / time domain) of the upper level radio resource block.

  That is, the encoding / data modulation unit 110 (allocation unit) of the base station 100 has a radio resource block size in the frequency domain or time domain, which is a lower level in the non-orthogonal multiplex region, at a higher level in the non-orthogonal multiplex region. The radio resource block is allocated to the non-orthogonal signal so as to be larger than the size in the frequency domain or time domain of the radio resource block.

  According to allocation example 2, since it is possible to share signal processing required for interference cancellation in the mobile station, the amount of processing is reduced (compared to allocation example 1, the number of users to be subjected to interference cancellation is reduced by one). doing). Also, in the lower level, users with a large path loss are multiplexed, and by assigning a relatively large size radio resource block to a user with a large path loss, that is, a user located at the cell edge, the base station 100 as a result. The effect of securing the coverage can be expected.

(3.3) Allocation example 3
FIGS. 8A and 8B are explanatory diagrams of a radio resource block allocation example 3. FIG. In the allocation example 3, a certain restriction is provided for allocation of radio resource blocks. Specifically, as shown in FIG. 8 (b), it is allowed to simultaneously allocate radio resource blocks in a plurality of frequency / time domains to the same user, but as shown in FIG. It is not allowed to assign.

  That is, when the encoding / data modulation unit 110 (allocation unit) of the base station 100 allocates a plurality of radio resource blocks to the same transmission destination (mobile stations 200A and 200B), Assign only level radio resource blocks.

  According to the allocation example 3, since only a radio resource block at any level in the non-orthogonal multiplex area is allocated, it is possible to suppress variations in processing delay associated with interference cancellation.

(3.4) Allocation example 4
FIG. 9 is an explanatory diagram of a radio resource block allocation example 4. In the allocation example 4, a transport block allocation method (encoding method) is defined. Specifically, when a plurality of frequency / time domain radio resource blocks are allocated to a specific mobile station (user), a method of independently coding (Separate coding), and coding the radio resource blocks together ( The method of joint coding) or a hybrid of both methods can be cited as candidates.

  In order to eliminate interference due to non-orthogonal signals addressed to other mobile stations as described above, separate coding is generally required. In allocation example 4, in the non-orthogonal multiplex region, Separate coding is applied to the lower level, and Joint coding is applied to the upper level (the highest level in the example of FIG. 9).

  That is, in the allocation example 4, at the lower level in the non-orthogonal multiplex area, information allocated to the radio resource block is encoded in units of radio resource blocks, and at the upper level in the non-orthogonal multiplex area, a plurality of radio resources are encoded. Information allocated to a radio resource block is encoded in units of blocks. In the example shown in FIG. 9, Joint coding is applied to three consecutive radio resource blocks in the frequency / time domain, but the radio resource blocks to which Joint coding is applied are not necessarily continuous. It doesn't matter.

  According to the allocation example 4, since the signal multiplexed at the higher level is less likely to be subject to interference cancellation by the non-orthogonal signal, the coding gain is improved by applying the joint coding only to the higher level. And efficient use of radio resources.

(3.5) Allocation example 5
FIG. 10 is an explanatory diagram of a radio resource block allocation example 5. Allocation example 5 is similar to allocation example 1 shown in FIG. 6 except that the boundary of radio resource blocks (frequency / time domain) is offset between levels in the non-orthogonal multiplex domain. That is, the encoding / data modulation unit 110 (allocation unit) of the base station 100 has a higher level in the non-orthogonal multiplex region where the boundary in the frequency domain or time domain of the radio resource block that is the lower level in the non-orthogonal multiplex region The radio resource block is allocated to the non-orthogonal signal so as to be different from the boundary in the frequency domain or time domain of the radio resource block. In the example shown in FIG. 10, all levels are offset in the same direction (right direction in the drawing), but the direction in which the boundary is offset may be different for each level.

  According to the allocation example 5, since the boundary of the radio resource block is offset and does not match between levels, it is possible to reduce interference between levels and reduce peak transmission power.

(4) Examples of Actions and Effects According to the mobile communication system 1 according to this embodiment, as described above, by defining the non-orthogonal multiplex region, the interference cancellation is automatically performed by the assigned radio resource block. The target mobile station (user) and radio resource block are uniquely determined. For this reason, since the processing load at the time of removing the multi-access interference using a non-orthogonal signal can be reduced, in the case of introducing hybrid orthogonal / non-orthogonal multi-access, it is possible to suppress an increase in cost and processing delay of a mobile station or the like.

(5) Other Embodiments As described above, the content of the present invention has been disclosed through one embodiment of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. should not do. From this disclosure, various alternative embodiments will be apparent to those skilled in the art.

  For example, FIG. 11 shows an example of radio resource block allocation according to a modification of the present invention. As shown in FIG. 11, the encoding / data modulation unit 110 (allocation unit) of the base station 100 near the boundary of the radio resource block (frequency / time domain), the radio resource block becomes closer to the boundary. Apply filtering to reduce transmit power density.

  In the example shown in FIG. 11, the transmission power of the radio resource block allocated to the level 1 user (positioned at the cell edge) in the non-orthogonal multiplex area is filtered to smoothly reduce the transmission power at the boundary of the radio resource block (Windowing ). Such filtering can reduce out-of-band radiation and peak power. Further, when the boundary is offset between the levels in the non-orthogonal multiplex area as in the above-described operation example 5, as shown in FIG. 11, the interference to the user at the level 2 (located in the center of the cell) Can be reduced.

  Further, the encoding / data modulation unit 110 may change the strength of filtering according to the level in the non-orthogonal multiplexing region. For example, the lower the level, the higher the filtering roll-off rate. Such filtering is applicable not only to the downlink but also to the uplink.

  In the above-described embodiment of the present invention, the example in the downlink direction from the base station 100 to the mobile stations 200A and 200B has been described. However, the present invention may be applied in the uplink direction. In addition, the present invention is not limited to between a base station and a mobile station, and may be applied to wireless communication between base stations.

  Furthermore, in the above-described embodiment, the case where hybrid orthogonal / non-orthogonal multiple access is introduced has been described as an example, but the scope of the present invention is not limited to hybrid orthogonal / non-orthogonal multiple access, Of course, the present invention can be applied to a mobile communication system in which non-orthogonal multiple access is used.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

1 ... Mobile communication system
100 ... Base station
110: Encoding / data modulation section
120 ... Base station scheduler
130 ... Hybrid orthogonal / non-orthogonal multiplexing section
140 ... Control signal generator
150 ... Control signal resource allocation unit
160 ... Physical channel multiplexer
200A, 200B ... Mobile station
210 ... Physical channel separator
220 ... Data demodulation / decoding unit
230 ... Purpose user control signal detector
240 ... Interference user control signal detector

Claims (9)

A radio signal receiving unit that receives a radio signal including a plurality of non-orthogonal signals that are not orthogonal to each other;
An interference cancellation unit that extracts a non-orthogonal signal addressed to the receiving device by demodulating and canceling a radio signal addressed to another receiving device from among the plurality of non-orthogonal signals received by the wireless signal receiving unit;
A demodulator that demodulates the signal destined for the receiving device extracted by the interference cancellation unit,
The radio resource block allocated to the non-orthogonal signal is defined by a frequency region, a time region, and a non-orthogonal multiplex region,
The non-orthogonal multiplex region has a plurality of levels according to the number of interference cancellations by the interference cancellation unit,
The interference canceling unit is a receiving device that cancels a non-orthogonal signal to which a radio resource block whose level is lower than that of the receiving device is assigned. A radio signal transmitter that transmits radio signals including a plurality of non-orthogonal signals that are not orthogonal to each other to a plurality of receiving devices located in the cell;
An allocating unit that allocates radio resource blocks to the non-orthogonal signals,
The transmission unit that allocates a radio resource block defined by a non-orthogonal multiplex region having a plurality of levels according to a frequency domain, a time region, and a number of interference cancellations in a reception device to the non-orthogonal signal.   In the frequency domain or time domain of the radio resource block, the size in the frequency domain or time domain of the radio resource block that is a lower level in the non-orthogonal multiplex area is higher in the frequency domain or time domain The transmission apparatus according to claim 2, wherein a radio resource block is allocated to the non-orthogonal signal so as to be larger than a size.   3. The transmission device according to claim 2, wherein, when allocating a plurality of radio resource blocks to the same transmission destination, the allocating unit allocates only a radio resource block at any level in the non-orthogonal multiplex region.   The radio signal transmission unit encodes information allocated to the radio resource block in units of the radio resource block at a lower level in the non-orthogonal multiplex region, and a plurality of information at an upper level in the non-orthogonal multiplex region. The transmission apparatus according to claim 2, wherein information assigned to the radio resource block is encoded in units of the radio resource block.   In the frequency domain or time domain of the radio resource block, the boundary in the frequency domain or time domain of the radio resource block that is the lower level in the non-orthogonal multiplexing domain is the allocation unit. The transmission apparatus according to claim 2, wherein a radio resource block is allocated to the non-orthogonal signal so as to be different from a boundary.   The transmission apparatus according to claim 6, wherein the allocating unit applies filtering that decreases a transmission power density as the boundary approaches the boundary in a frequency domain or a time domain of the radio resource block.   The transmission device according to claim 7, wherein the allocation unit changes the filtering strength according to the level in the non-orthogonal multiplex region. A communication device receiving a radio signal including a plurality of non-orthogonal signals that are not orthogonal to each other;
The communication device extracts a non-orthogonal signal addressed to the receiving device by demodulating and canceling a radio signal addressed to another receiving device from among the received non-orthogonal signals;
The communication device includes a step of demodulating the signal addressed to the receiving device extracted in the extracting step,
The radio resource block allocated to the non-orthogonal signal is defined by a frequency region, a time region, and a non-orthogonal multiplex region,
The non-orthogonal multiplex region has a plurality of levels according to the number of interference cancellations in the communication device,
In the step of canceling the interference, a radio communication method for canceling a non-orthogonal signal to which a radio resource block whose level is lower than that of the own device is assigned.

Images