JP2009189066A - Radio communication apparatus and receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain improvement in characteristics during retransmission by using a corresponding relation between a resource block to be used for a transmission packet and a resource block to be used for a retransmission packet. <P>SOLUTION: A radio communication apparatus includes a resource block determination unit and a receiving unit. In the resource block determination unit, a frame in which a plurality of resource blocks are disposed in a frequency direction is formed iteratively in a time direction and on the basis of an allocation pattern of the resource block that uses a frame number as a parameter, the following resource block number is determined from the preceding resource block number. The receiving unit is configured to receive a packet from the resource block corresponding to the following resource block number determined in the resource block determination unit. The resource block determination unit determines the following resource block number on the basis of the remainder in a case where a value including the value corresponding to the frame number and the preceding resource block number is divided with the number of resource blocks in the frequency direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus and method for performing retransmission using a plurality of resource blocks.

  Hybrid ARQ refers to a technique in which an error correction technique is added to an existing ARQ function (error detection / retransmission function). In Hybrid ARQ, error correction can be performed by transmitting an error correction code in advance, and the number of packet retransmissions can be reduced.

  There are two types of hybrid ARQ as shown in FIG. One is called synchronous ARQ (Synchronous ARQ), and the other is called asynchronous ARQ (Asynchronous ARQ).

  Synchronous ARQ refers to performing retransmission at a predetermined retransmission timing. For example, when a transmission packet of # 0 (S00) is detected as an error, the retransmission is performed using # 0 (S10), # 0 ( This can be done only in S20). That is, retransmission is performed with a frame that is an integral multiple of RTT (Round Trip Time: also called control loop delay).

  The advantage of this synchronous ARQ is that since the retransmission timing is determined in advance, it is not necessary to transmit the process number indicating the original transmission packet of the retransmission packet as a control bit, and overhead can be reduced. There is also an advantage that the processing is simple. However, there is a drawback that scheduling flexibility when assigning to TTI (Transmission Time Interval) is small due to restrictions on retransmission timing. Furthermore, if it cannot be sent after 1 RTT, it needs to be sent at least after 2 RTT, which may increase the delay.

  Asynchronous ARQ refers to retransmission in which a retransmission packet can be transmitted at any time after 1 RTT, and the retransmission timing is not determined. For example, when a transmission packet of # 0 (A00) is detected as an error, The retransmission may be performed by any TTI after (A10). That is, retransmission may be performed at any TTI (A10 to A25) after 1 RTT. Asynchronous ARQ is used in HSDPA (Non-Patent Document 1).

  The advantage of this asynchronous ARQ is that scheduling flexibility is great. Further, when transmission is not possible after 1 RTT, transmission is possible not after 2 RTT but after (RTT + 1), so the possibility of an increase in delay is small. On the other hand, there is a drawback that the processing becomes complicated. Further, it is necessary to transmit the process number as a control bit, and there is a disadvantage that overhead is increased.

3GPP TS 25.212, "Multiplexing and channel coding (FDD)"

  In the case of using frequency domain scheduling composed of a plurality of resource blocks, if retransmission is performed using the above-described synchronous ARQ and asynchronous ARQ, the following problem occurs.

  In synchronous ARQ, as shown in FIG. 2A, since retransmission is performed using the same resource block (frequency block), an error is redetected at the time of retransmission when the communication quality of the resource block is poor. There is a problem that the possibility is high.

  On the other hand, in asynchronous ARQ, it is possible to retransmit using an optimal resource block. However, what is used among resource blocks after 1 RTT shown in FIG. Processing becomes complicated.

  The present invention has been made in view of the above-described prior art, and by using the correspondence between resource blocks used in transmission packets and resource blocks used in retransmission packets, The purpose is to improve the characteristics.

In order to solve the above-described object of the present invention, a wireless communication device includes:
A frame in which multiple resource blocks are arranged in the frequency direction is repeatedly formed in the time direction. Based on the resource block allocation pattern that uses the frame number as a variable, the resource block number after the previous resource block number A resource block determination unit for determining
A receiving unit that receives a packet by a resource block corresponding to the subsequent resource block number determined by the resource block determining unit;
The resource block determination unit, based on a remainder when a value including a value corresponding to a frame number and the previous resource block number is divided by the number of resource blocks in the frequency direction, The number is determined.

In order to solve the above object of the present invention, a wireless communication device
A frame in which a plurality of resource blocks are arranged in the frequency direction is repeatedly formed in the time direction, and the resource block number when the nth data is received based on the resource block allocation pattern using the frame number as a variable A resource block determination unit for determining a resource block number when receiving the (n + 1) th data,
A receiving unit that receives a packet by a resource block corresponding to a resource block number determined by the resource block determining unit;
The resource block determination unit is based on a remainder when a value including a value corresponding to a frame number and a resource block number when receiving n-th data is divided by the number of resource blocks in the frequency direction. , Determining the resource block number when receiving the (n + 1) th data.

In order to solve the above object of the present invention, a wireless communication device
A resource block determination unit that determines a resource block for retransmission based on a resource block allocation pattern in which a frame in which a plurality of resource blocks are arranged in the frequency direction is repeatedly formed in the time direction and the frame number is used as a variable When,
A receiving unit for receiving a packet by the resource block for retransmission determined in the resource block determining unit,
The resource block determination unit determines a resource block for retransmission based on a remainder when a value corresponding to a frame number is divided by the number of resource blocks in the frequency direction.

In order to solve the above-mentioned object of the present invention, a receiving method includes:
A frame in which multiple resource blocks are arranged in the frequency direction is repeatedly formed in the time direction. Based on the resource block allocation pattern that uses the frame number as a variable, the resource block number after the previous resource block number A step of determining
Receiving a packet by a resource block corresponding to the determined subsequent resource block number,
In the determining step, the subsequent resource block number is based on a remainder when a value including a value corresponding to a frame number and the previous resource block number is divided by the number of resource blocks in the frequency direction. It is characterized by determining.

In order to solve the above-mentioned object of the present invention, a receiving method includes:
A frame in which a plurality of resource blocks are arranged in the frequency direction is repeatedly formed in the time direction, and the resource block number when the nth data is received based on the resource block allocation pattern using the frame number as a variable To determine a resource block number when receiving the (n + 1) th data;
Receiving a packet by a resource block corresponding to the determined resource block number,
The step of determining is based on a remainder when a value including a value according to a frame number and a resource block number when receiving n-th data is divided by the number of resource blocks in the frequency direction, The resource block number for receiving the (n + 1) th data is determined.

In order to solve the above-mentioned object of the present invention, a receiving method includes:
A frame in which a plurality of resource blocks are arranged in a frequency direction is repeatedly formed in a time direction, and a resource block for retransmission is determined based on an allocation pattern of resource blocks using a frame number as a variable;
Receiving a packet with the determined resource block for retransmission, and
The determining step is characterized in that a resource block for retransmission is determined based on a remainder when a value corresponding to a frame number is divided by the number of resource blocks in the frequency direction.

  As described above, according to the embodiment of the present invention, it is possible to obtain a frequency diversity effect at the time of retransmission, and to improve the characteristics of retransmission.

The figure which shows two systems of hybrid ARQ of a prior art A diagram showing retransmission in hybrid ARQ of the prior art when using frequency domain scheduling Schematic illustrating a retransmission method according to an embodiment of the present invention Configuration diagram of a communication system to which the present invention is applied The figure which shows the 1st correspondence of the resource block of an initial transmission packet, and the resource block of a retransmission packet The figure which shows the 2nd corresponding | compatible relationship between the resource block of an initial transmission packet, and the resource block of a retransmission packet The figure which shows the 3rd corresponding | compatible relationship between the resource block of an initial transmission packet, and the resource block of a retransmission packet

  Embodiments of the present invention will be described in detail below with reference to the drawings.

  FIG. 3 is a schematic diagram illustrating a retransmission method according to an embodiment of the present invention. Unlike the above-described synchronous ARQ, the present invention uses different resource blocks (frequency blocks) for original transmission packets (referred to as initial transmission packets) and retransmission packets. As shown in FIG. 3 (a), the initial transmission packet and the retransmission packet have their resource blocks interchanged in a predetermined order, and this correspondence relationship is established in advance between the transmitting side wireless communication device and the receiving side wireless communication device. Store it. As shown in FIG. 3B, the transmitting-side wireless communication apparatus constructs a retransmission packet based on a predetermined correspondence, and transmits it to the receiving side after 1 RTT. The receiving-side wireless communication device can perform error detection (and error correction) based on the correspondence relationship.

  In this way, by applying frequency hopping to the retransmission packet, transmission is performed with resource blocks having different frequencies during retransmission, so that a frequency diversity effect can be obtained.

(Configuration example)
FIG. 4 is a diagram showing a configuration diagram of a communication system to which the present invention is applied. The communication system includes a transmission side wireless communication device (transmission unit) 10 shown in FIG. 4A and a reception side wireless communication device (reception unit) 12 shown in FIG.

  The transmitting-side radio communication device 10 is typically used for a base station of a radio communication system, but may be used for another device such as a mobile station. The transmitting-side radio communication device 10 includes a pattern storage unit 103, a packet scheduling unit 105, a channel encoding unit 107, a data modulation unit 109, and a radio resource allocation unit 111.

  The pattern storage unit 103 stores the correspondence between resource blocks used in transmission packets and resource blocks used in retransmission packets. As will be described below, the pattern storage unit may store in advance the correspondence relationship of resource blocks used for transmission up to the maximum number of retransmissions, and assign the resource block allocation pattern of retransmission packets from the initial transmission packet. You may store the predetermined | prescribed correspondence which can be produced | generated. The packet scheduling unit 105 receives data from each user and forms a transmission packet or a retransmission packet. At the time of initial transmission, scheduling is performed to allocate data from each user to resource blocks # 1 to #N based on feedback information such as signal quality. At the time of retransmission (when a retransmission request signal is received from the reception-side wireless communication apparatus), data from each user is configured into a retransmission packet based on the correspondence stored in the pattern storage unit 103. For example, in the case of a retransmission packet, as shown in FIG. 3B, rearrangement is performed so that a resource block different from the initial transmission packet is used. The channel encoding unit 107 encodes the transmission data (transmission packet or retransmission packet) configured by the packet scheduling unit 105 according to some encoding algorithm. The data modulator 109 modulates the data encoded by the channel encoder 107. Data modulation is performed using a modulation scheme suitable for each resource block. For example, various modulations such as QPSK, 16QAM, and 64QAM are used. Radio resource allocating section 111 performs allocation to resource blocks # 1 to #N based on the scheduling configured by packet scheduling section 105.

  As will be described later, the common control channel is used when the correspondence stored in the pattern storage unit 103 is transmitted to the reception-side wireless communication apparatus through the broadcast channel.

  The receiving-side wireless communication device 12 includes a wireless resource allocation unit 121, a pattern storage unit 123, and a data demodulation / retransmission control unit 125.

  The pattern storage unit 123 stores information common to the correspondence stored in the pattern storage unit 103 of the transmission-side wireless communication device 10. A correspondence relationship uniquely determined between the transmission-side wireless communication device 10 and the reception-side wireless communication device 12 may be stored in advance, and a correspondence relationship between the transmission-side wireless communication device 10 and the reception-side wireless communication device 12 may be stored. May be communicated with each other to store common information. The radio resource allocating unit 121 recognizes in advance whether the packet is the initial transmission packet or the retransmission packet from the retransmission request signal transmitted before the RTT, so in the case of the initial transmission packet, the resource block # 1 A predetermined resource block is extracted from ~ # N. In the case of a retransmission packet, resource blocks used in the receiving-side wireless communication device are extracted from resource blocks # 1 to #N based on the correspondence relationship stored in the pattern storage unit. The data demodulation / retransmission control unit 125 demodulates the extracted resource block to configure user data. Thereafter, error detection (and error correction) is performed, and a retransmission request signal is transmitted to the transmission-side wireless communication apparatus as necessary.

(How to determine correspondence)
FIG. 5 is a diagram illustrating a first correspondence between the resource block of the initial transmission packet and the resource block of the retransmission packet. In the first correspondence relationship, the correspondence relationship up to the maximum number of transmissions is determined in advance by the transmission-side wireless communication device and the reception-side wireless communication device. In this way, the degree of freedom in changing the correspondence pattern is increased, and it is possible to determine in advance a configuration that provides the most diversity effect. On the other hand, as the maximum number of transmissions increases, the amount of correspondence information stored increases.

  FIG. 6 is a diagram illustrating a second correspondence relationship between the resource block of the initial transmission packet and the resource block of the retransmission packet. In the second correspondence relationship, the correspondence relationship between the n-th transmission and the (n + 1) -th transmission is determined in advance by the transmission-side wireless communication device and the reception-side wireless communication device. By doing so, it is possible to reduce the amount of correspondence information stored as compared with FIG. On the other hand, as shown in FIG. 6, for example, the resource blocks used for the first transmission and the third transmission may be the same, and the diversity effect may be reduced compared to FIG.

  FIG. 7 is a diagram illustrating a third correspondence relationship between the resource block of the initial transmission packet and the resource block of the retransmission packet. In the third correspondence relationship, a correspondence relationship pattern is generated based on a variable that is common to the transmission-side wireless communication device and the reception-side wireless communication device. For example, since the frame number is reported as system information, a pattern can be generated using this frame number as a variable. As a method for generating a pattern from a frame number, for example, the following expression can be used.

Chunk (n + 1) = (Chunk (n) + ΔFN) mod (MAX_CHUNK)
n indicates the number of transmissions, n = 1 at the first transmission, and n = 2 at the first retransmission. Chunk (n) indicates the number of the resource block when data is transmitted for the nth time. In FIG. 7, since there are 6 resource blocks, Chunk (n) corresponds to the number assigned from 0 to 5 To do. That is, Chunk (n) of the first transmission packet # 0 is 0, and Chunk (n) of the first transmission packet # 1 is 1. ΔFN is the amount of change in frame number (4 in FIG. 7), and MUX_CHUNK is the maximum number of resource blocks (6 in FIG. 7).

  Based on this equation, the resource block Chunk (n + 1) transmitted when the first transmission packet # 0 is retransmitted once can be obtained, Chunk (n + 1) = (0 + 4) mod (6) = Become 4. Thus, by calculating the correspondence at the time of retransmission based on a predetermined variable, it is possible to reduce the amount of information of the correspondence stored as compared with FIG. Also in this case, for example, the resource blocks used for the first transmission and the third transmission may be the same, and the diversity effect may be reduced as compared with FIG.

(Correspondence notification method)
Next, a method for notifying the correspondence relationship from one to the other will be described in order to maintain the correspondence relationship defined by using FIGS.

  First, there is a method in which the correspondence is uniquely determined in advance and held in common in the pattern storage units (103 and 123 in FIG. 4) of the transmission side wireless communication device and the reception side wireless communication device. This method has a feature that the overhead is reduced because it is not necessary to notify the correspondence relationship from the transmitting wireless communication device to the receiving wireless communication device or from the receiving wireless communication device to the transmitting wireless communication device. On the other hand, the correspondence cannot be changed.

  Secondly, there is a method of transmitting as system information through a broadcast channel. For example, the correspondence relationship can be changed for each cell using a broadcast channel. The correspondence stored in the pattern storage unit (103 in FIG. 4) of the transmission side wireless communication device is transmitted to the reception side wireless communication device using the broadcast channel (not shown) using the common control channel and received. Stored in the pattern storage unit (123 in FIG. 4) of the side wireless communication apparatus. In this way, a plurality of correspondence patterns can be held and the pattern can be changed, but the overhead increases compared to the first method.

  Thirdly, there is a method of notifying a shared data channel as layer 3 signaling at the time of call setup. The correspondence stored in the pattern storage unit (103 in FIG. 4) of the transmitting-side wireless communication apparatus is the shared channel (input to the packet scheduling unit 105 in FIG. 4 as data from each user and transmitted to the shared channel). Is transmitted to the reception-side wireless communication device and stored in the pattern storage unit (123 in FIG. 4) of the reception-side wireless communication device. In this way, a different pattern can be set for each call setting, but the overhead increases.

  As described above, according to the embodiment of the present invention, it is possible to obtain a frequency diversity effect at the time of retransmission, and to improve the characteristics of retransmission.

  The following items are further disclosed regarding the embodiment including the above examples.

(1) A wireless communication apparatus having a retransmission function that transmits a retransmission packet when an error is detected in a transmission packet transmitted by a plurality of resource blocks:
A pattern storage unit that stores a correspondence relationship between resource blocks used in the transmission packet and resource blocks used in the retransmission packet; and a packet scheduling unit that configures the retransmission packet based on the correspondence relationship;
A wireless communication device.

  The wireless communication apparatus according to (1), wherein the pattern storage unit stores a correspondence relationship of resource blocks used for transmission up to a maximum number of retransmissions.

  (1) The pattern storage unit stores a correspondence relationship between a resource block used at the n-th transmission and a resource block used at the (n + 1) -th transmission. Wireless communication device.

  The wireless communication apparatus according to (1), wherein the pattern storage unit stores a correspondence relationship based on a variable that is common to the transmission-side wireless communication apparatus and the reception-side wireless communication apparatus.

  The wireless communication apparatus according to (1), wherein the wireless communication apparatus stores in advance the correspondence relationship uniquely determined by the transmission-side wireless communication apparatus and the reception-side wireless communication apparatus in the pattern storage unit.

  The wireless communication device according to (1), wherein the wireless communication device transmits the correspondence stored in the pattern storage unit as system information through a broadcast channel.

  The wireless communication device according to (1), wherein the wireless communication device transmits the correspondence stored in the pattern storage unit as layer 3 signaling through a shared data channel.

A method for transmitting a retransmission packet from a transmission side wireless communication device when an error is detected in the transmission packet transmitted by a plurality of resource blocks from the transmission side wireless communication device by the reception side wireless communication device:
The transmitting-side wireless communication device and the receiving-side wireless communication device store a correspondence relationship between resource blocks used in transmission packets and resource blocks used in retransmission packets;
The transmitting-side wireless communication device, when transmitting a retransmission packet, constructing a retransmission packet based on the correspondence, and transmitting the retransmission packet to the receiving-side wireless communication device; and the receiving-side wireless communication device Detecting a retransmission error based on the correspondence;
Having a method.

  In addition, this invention is not limited to said Example, A various change and application are possible within a claim.

DESCRIPTION OF SYMBOLS 10 Transmission side radio | wireless communication apparatus 12 Reception side radio | wireless communication apparatus 103 Pattern storage part 105 Packet scheduling part 107 Channel encoding part 109 Data modulation part 111 Radio | wireless resource allocation part 121 Radio | wireless resource allocation part 123 Pattern storage part 125 User data structure part 127 Channel Processing part

Claims (14)

A frame in which multiple resource blocks are arranged in the frequency direction is repeatedly formed in the time direction. Based on the resource block allocation pattern that uses the frame number as a variable, the resource block number after the previous resource block number A resource block determination unit for determining
A receiving unit that receives a packet by a resource block corresponding to the subsequent resource block number determined by the resource block determining unit;
The resource block determination unit, based on a remainder when a value including a value corresponding to a frame number and the previous resource block number is divided by the number of resource blocks in the frequency direction, A wireless communication apparatus for determining a number. A frame in which a plurality of resource blocks are arranged in the frequency direction is repeatedly formed in the time direction, and the resource block number when the nth data is received based on the resource block allocation pattern using the frame number as a variable A resource block determination unit for determining a resource block number when receiving the (n + 1) th data,
A receiving unit that receives a packet by a resource block corresponding to a resource block number determined by the resource block determining unit;
The resource block determination unit is based on a remainder when a value including a value corresponding to a frame number and a resource block number when receiving n-th data is divided by the number of resource blocks in the frequency direction. , Determining the resource block number when receiving the (n + 1) th data. A resource block determination unit that determines a resource block for retransmission based on a resource block allocation pattern in which a frame in which a plurality of resource blocks are arranged in the frequency direction is repeatedly formed in the time direction and the frame number is used as a variable When,
A receiving unit for receiving a packet by the resource block for retransmission determined in the resource block determining unit,
The resource block determination unit determines a resource block for retransmission based on a remainder when a value corresponding to a frame number is divided by the number of resource blocks in a frequency direction.   The radio communication apparatus according to claim 1, wherein the resource block determination unit stores in advance a uniquely determined allocation pattern.   The radio communication apparatus according to any one of claims 1 to 3, wherein the resource block determination unit sets an allocation pattern based on the received broadcast channel.   The wireless communication apparatus according to claim 5, wherein the frame number is included in a broadcast channel.   The radio communication apparatus according to claim 1, wherein the resource block determination unit sets an allocation pattern based on the received shared data channel. A frame in which multiple resource blocks are arranged in the frequency direction is repeatedly formed in the time direction. Based on the resource block allocation pattern that uses the frame number as a variable, the resource block number after the previous resource block number A step of determining
Receiving a packet by a resource block corresponding to the determined subsequent resource block number,
In the determining step, the subsequent resource block number is based on a remainder when a value including a value corresponding to a frame number and the previous resource block number is divided by the number of resource blocks in the frequency direction. Determining a reception method. A frame in which a plurality of resource blocks are arranged in the frequency direction is repeatedly formed in the time direction, and the resource block number when the nth data is received based on the resource block allocation pattern using the frame number as a variable To determine a resource block number when receiving the (n + 1) th data;
Receiving a packet by a resource block corresponding to the determined resource block number,
The step of determining is based on a remainder when a value including a value according to a frame number and a resource block number when receiving n-th data is divided by the number of resource blocks in the frequency direction, A receiving method, comprising: determining a resource block number when receiving n + 1th data. A frame in which a plurality of resource blocks are arranged in a frequency direction is repeatedly formed in a time direction, and a resource block for retransmission is determined based on an allocation pattern of resource blocks using a frame number as a variable;
Receiving a packet with the determined resource block for retransmission, and
The determining step determines a resource block for retransmission based on a remainder when a value corresponding to a frame number is divided by the number of resource blocks in the frequency direction.   The receiving method according to claim 8, wherein the determining step stores in advance a uniquely determined allocation pattern.   The receiving method according to claim 8, wherein the determining step sets an allocation pattern based on the received broadcast channel.   The reception method according to claim 12, wherein the frame number is included in a broadcast channel.   11. The receiving method according to claim 8, wherein the determining step sets an allocation pattern based on the received shared data channel.

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