Base station device, user device and method for mobile communication system

The present invention relates to the technical field of mobile communication, and more particularly to mobile communication systems, base station devices, user devices and methods using next-generation mobile communication technology.

In this type of technology, the so-called third-generation successor mobile communication system is being studied by 3GPP, a standardization body for wideband code division multiple access (W-CDMA) systems. In particular, as a successor to the W-CDMA system, high-speed downlink packet access (HSDPA) system, high-speed uplink packet access (HSUPA) system, etc., not only long term evolution (LTE) but also subsequent mobile communication systems Is also under consideration. Examples of successors to LTE systems include LTE-Advanced or 4th generation mobile communication systems.

FIG. 1 shows a conceptual diagram of a mobile communication system. The mobile communication system includes the cell 50 and the user device 100 located in the cell 50.₁,100₂,100₃The base station apparatus 200 that wirelessly communicates with the user apparatus, the upper node 300 connected to the base station apparatus, and the core network 400 connected to the upper node are included. The upper node 300 may be, for example, a wireless network controller (RNC), an access gateway (aGW), a mobility management entity (MME), or the like.

The downlink radio access method in the LTE system is the Orthogonal Frequency Division Multiplexing (OFDM) method. For uplink, the Single-Carrier Frequency Division Multiple Access (SC-FDMA) method is used. However, in another system, a multi-carrier system may be used for the uplink.

The OFDM method is a multi-carrier transmission method in which a frequency band is divided into a plurality of narrow frequency bands (subcarriers), and data is carried on each subcarrier for transmission. By arranging the subcarriers closely while being orthogonal to the frequency axis, high-speed transmission can be realized and frequency utilization efficiency can be expected to increase.

The SC-FDMA system is a single carrier transmission system in which a frequency band is divided for each terminal and transmission is performed between a plurality of terminals using different frequency bands. This method is preferable from the viewpoint of reducing the power consumption of the terminals and expanding the coverage because the fluctuation of the transmission power can be reduced in addition to being able to easily and effectively reduce the interference between the terminals.

In the LTE system, communication is performed by assigning one or more resource blocks (RB: Resource Block) or resource units (RU: Resource Unit) to the user device in both downlink and uplink. Resource blocks are shared by many user devices in the system. The base station device determines which user device among the plurality of user devices is assigned the resource block for each sub-frame, which is 1 ms in LTE. Subframes may be referred to as transmission time intervals (TTIs). Determining the allocation of radio resources is called scheduling. On the downlink, the base station device transmits a shared data channel with one or more resource blocks to the user device selected by scheduling. This shared data channel is a downlink physical shared channel (PDSCH:) It is called Physical Downlink Shared CHannel). On the uplink, the user device selected by scheduling sends a shared channel to the base station device with one or more resource blocks. This shared channel is called a physical uplink shared CHannel (PUSCH).

In a communication system using a shared channel as described above, in principle, it is necessary to signal (notify) which user device the shared channel is assigned to for each subframe. The control channel used for this signaling is called a physical downlink control channel (PDCCH) or a downlink L1 / L2 control channel (DL-L1 / L2 control channel). In addition to this PDCCH, the downlink control signal may include a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), and the like.

The PDCCH may contain, for example, the following information (see, for example, Non-Patent Document 1): Downlink Scheduling Grant, Uplink Scheduling Grant, Overload Indicator and -Transmission Power Control Command Bit.

The downlink scheduling information includes, for example, information about the shared channel of the downlink, specifically, the allocation information of the resource block of the downlink, the identification information (UE-ID) of the user device, the number of streams, and the precoding vector. Information on (Pre-coding Vector), data size, modulation method, information on HARQ (Hybrid Automatic Repeat reQuest), etc. are included.

In addition, the uplink scheduling grant contains, for example, information about the uplink shared channel, specifically, uplink resource allocation information, user device identification information (UE-ID), data size, modulation. It includes information such as method, uplink transmission power information, and Demodulation Reference Signal in uplink MIMO (Uplink MIMO).

PCFICH is information for notifying the format of PDCCH. More specifically, PCFICH informs the number of mapped OFDM symbols of PDCCH. In LTE, the number of mapped OFDM symbols in PDCCH is 1, 2 or 3, and they are mapped in order from the OFDM symbol at the beginning of the subframe.

PHICH includes delivery confirmation information (ACK / NACK: Acknowledgment / Non-Acknowledgment information) indicating whether or not retransmission is required for PUSCH transmitted on the uplink. Since PHICH indicates the correctness for each transmission unit such as one packet, it can basically be expressed by one bit. Therefore, it is not advantageous for wireless transmission as it is. Therefore, PHICH for several people is collected to form multi-bit information, and the information is multiplexed and diffused by a code multiplexing method and transmitted wirelessly.

Although it is a matter of definition of terms, PDCCH, PCFICH and PHICH may be defined as independent channels that are equal to each other as described above, or PCFICH and PHICH are defined to be included in PDCCH. You may.

On the uplink, PUSCH transmits user data (normal data signal) and associated control information. In addition to PUSCH, downlink quality information (CQI: Channel Quality Indicator) and PDSCH delivery confirmation information (ACK / NACK) are transmitted by the uplink control channel (PUCCH: Physical Uplink Control CHannel). CQI is used for scheduling processing, adaptive modulation / demodulation and coding processing (AMCS) of shared physical channels on the downlink. On the uplink, a random access channel (RACH), a signal indicating a request for allocation of radio resources on the upper and lower links, and the like are also transmitted as needed.<nplcit num="1"><text>3GPP R1-070103, Downlink L1 / L2 Control Signaling Channel Structure: Coding</text></nplcit>

<p> Since the mobile communication system as described above includes a wireless link, a kind of signal delay that does not occur in a wired system occurs. This signal delay may be referred to as a radio interface delay or an air interface delay. Needless to say, this signal delay should be reduced as much as possible from the viewpoint of speeding up communication.</p><p> Figure 2 shows the breakdown of the air interface delay. As shown in FIG. 2, not only the air interface delay but also the transmission line delay and the processing delay in the RNC exist, but the transmission line delay and the processing delay in the RNC can be considerably shortened. It's not important, so I'll ignore it. In general, air interface delays include (a) transmit delays, (b) retransmission delays and (c) receive delays. (a) Transmission delay represents the period from the start of transmission to the completion of all transmission signals. For example, when transmitting data for 1 TTI, a period of about 1.5 TTI is required as a whole, considering the delay required for the transmission process. (b) Retransmission delay represents the delay required when retransmission control (HARQ) is performed. If the data sent by a TTI needs to be retransmitted, the system has decided that the data should be retransmitted after 8 TTIs. Depending on the radio propagation situation, retransmission may or may not be required. If retransmission is required with a probability of 50%, an average delay of about 8 TTI x 1/2 = 4 TTI will occur. (c) The reception delay represents the period required to receive and demodulate the transmitted data. When receiving data for 1 TTI, it takes, for example, a period of about 2 TTI. Therefore, the air interface delay can be estimated to be about 7.5 TTI as a whole. Retransmission delay accounts for the largest proportion of this, so if this can be shortened, faster wireless access can be achieved.</p><p> On the other hand, when various old and new systems coexist in the same area, it is extremely important that the new system has sufficient backward compatibility or coexistence with the old system. In particular, a configuration in which old and new systems are transmitted and received simultaneously at the same frequency (W-CDMA and HSDPA correspond to this) enables prompt introduction of the new system. Otherwise, the transition from the old system to the new system will be difficult to proceed quickly.</p><p> An object of the present invention is to reduce the delay due to the air interface of the new system while ensuring backward compatibility with the old system, specifically, in a state where the new system and the old system coexist at the same frequency.</p>

<p> In one embodiment of the present invention, a base station device for mobile communication used in an area where at least the first and second systems having different packet retransmission intervals coexist is used. The base station apparatus includes a scheduling means for determining radio resources of each user apparatus of both the first and second systems, a transmission means for transmitting a downlink control channel and a downlink shared data channel, and delivery confirmation information for the downlink shared data channel. It has a receiving means for receiving an uplink control channel including. The downlink control channel includes a plurality of control channel elements, and control information addressed to each user device is associated with one or more control channel elements. The radio resource used by each user device that has received the downlink shared data channel to transmit the uplink control channel is specified according to which control channel element the control information addressed to each user device corresponds to.</p><p> When the downlink shared data channel of a certain subframe is assigned to the user device of the first system and the control information addressed to the user device is assigned to a certain control channel element, from the certain subframe. When the downlink shared channel of the subframe after a predetermined period is assigned to the user device of the second system, the control information addressed to the user device of the second system is a control channel element different from the certain control channel element. May be associated with.</p><p> Alternatively, the radio resources for the uplink control channel may be separately prepared for each of the first and second systems.</p><p> Alternatively, the control information addressed to the user device of the second system is associated with the same control channel element as the control information addressed to the user device of the first system, but may be spread with a different spreading code.</p>

<p> According to the present invention, it is possible to reduce the delay due to the air interface of the new system while ensuring backward compatibility with the old system.</p>

For convenience of explanation, the present invention will be described from the following viewpoints, but the classification of each item is not essential to the present invention, and the items described in two or more items may be combined as necessary. .. Although explanations are given using specific numerical examples in order to promote understanding of the invention, these numerical values are merely examples and any appropriate value may be used unless otherwise specified.

1. Down signal format 2. Upstream signal format 3. First operation example 4. Second operation example 5. Base station equipment 6. User device

&lt;<u style="single">1. Down signal format</u>&gt; Figure 3 shows an example of a subframe configuration. In downlink transmission, one subframe is, for example, 0.5 ms or 1 ms, and there are 14 OFDM symbols in one subframe. In FIG. 3, the numbers in the time axis direction (# 1, # 2, # 3, ..., # 14) indicate the numbers that identify the OFDM symbols, and the numbers in the frequency axis direction (# 1, # 2, # 3). , ..., # L-1, # L, L are positive integers) indicate the number that identifies the resource block.

The physical downlink control channel PDCCH and the like are mapped to the M OFDM symbols at the beginning of the subframe. Three types of M values are set: 1, 2, and 3. In FIG. 3, the physical downlink control channel is mapped to the two OFDM symbols from the beginning of one subframe, that is, OFDM symbols # 1 and # 2 (that is, M = 2). Then, in an OFDM symbol other than the OFDM symbol to which the physical downlink control channel PDCCH is mapped, user data, a synchronization channel (SCH: Synchronization Channel), a broadcast channel (BCH: Physical Broadcast Channel), and / or persistent scheduling ( The data channel to which Persistent Scheduling) is applied is mapped.

Figure 4 schematically shows how six PDCCHs are mapped to the first two OFDM symbols. The above-mentioned user data includes, for example, IP packets by web browsing, file transfer (FTP), voice packet (VoIP), and control signals for processing radio resource control (RRC). User data is mapped to DL-SCH on the transport channel and transmitted on PDSCH on the physical channel.

In the example of FIG. 3, L resource blocks are prepared in the system band in the frequency direction. The frequency band per resource block is, for example, 180 kHz, and there are, for example, 12 subcarriers in one resource block. The total number of resource blocks L may be 25 when the system bandwidth is 5 MHz, 50 when the system bandwidth is 10 MHz, 100 when the system bandwidth is 20 MHz, and so on. .. For convenience of explanation, a radio resource specified by the time occupied by one OFDM symbol and the frequency occupied by one subcarrier is referred to as a resource element (RE).

When the user device receives the downlink signal, it separates the control signal from other signals from the subframe. First, by determining the value of PCFICH, it is determined how many OFDM symbols are assigned to the control signal in the subframe. Next, the user device performs blind detection and confirms the existence or nonexistence of the control signal addressed to the own device. In general, blind detection is performed based on the error determination result using the identification information (UE-ID) of the own device for each possible combination of the detection start position (specific resource element) and the channel code rate. ..

FIG. 5 schematically shows how PDCCHs with different channel coding rates are multiplexed in the same subframe. The longer drawn PDCCH is encoded with a smaller channel coding rate. For example, PDCCH # 2 is encoded with a channel coding rate R / 2, which is smaller than the channel coding rate R of PDCCH # 1. If there are many options for the detection start position and the channel coding rate, there is a concern that the arithmetic processing load required for blind detection will become excessive and the burden on the user device will increase. Therefore, the start position of blind detection is limited to a specific position as indicated by the upward arrow. This makes it possible to reduce the number of choices regarding the starting position. For convenience of explanation, candidates for the start position of blind detection are set for each predetermined number of resource elements, and the predetermined number of resource elements are control channel elements (CCE:). It is referred to as Control Channel Element). CCE corresponds to the mapping start position of the control information. In the case of Figure 5, the up arrow indicates (the starting position of) the six control channel elements. A resource element is a unit of resource identified by one subcarrier and one OFDM symbol.

&lt;<u style="single">2. Upstream signal format</u>&gt; FIG. 6 shows an example of a signal format on the uplink. In the illustrated example, the control information transmission method differs depending on whether or not a resource block is allocated for data channel transmission. If no resource block has been allocated for data channel transmission, the L1 / L2 control channels (# 0, # 1, # 2, # 3) that the user sends to the base station equipment are the first and second controls. It is transmitted while frequency hopping in the band. However, if a resource block is allocated for data channel transmission, the control information is transmitted in that resource block. In this case, the control information and the data channel are multiplexed by the time division multiplexing method. In the illustrated example, resource blocks are assigned to the user devices UE11 to UE15, and their own data channels and control information are transmitted in the resource blocks. The reason why the first and second control bands are hopping as shown in the figure is to obtain the frequency diversity effect. When the single carrier method is used for the uplink, the first and second control bands are not used by the same user at the same time. However, when the multi-carrier system is used for the uplink, the first and second control bands may be used simultaneously by the same user, unlike the illustrated example.

&lt;<u style="single">3. First example of operation-downlink data transmission</u>&gt; In the operation example described below, it is assumed that two old and new systems with different retransmission periods provide services in the same area. A typical example of the old system is an LTE mobile communication system, but other systems may be used. A typical example of the new system is the LTE advanced system, but other systems may be used. For convenience of explanation, two systems, old and new, will appear, but this is not essential to the present invention. The present invention is widely applicable when a plurality of systems having different retransmission periods or RTDs (Round Trip Delays) coexist.

As shown in FIG. 7, the physical downlink shared data channel (PDSCH) is transmitted, its acknowledgment information (ACK / NACK) is transmitted on the physical uplink control channel (PUCCH), and in the case of NACK, retransmission is performed. To. PUCCH (ACK / NACK) is transmitted 3 TTI after receiving a new packet (4 TTI after the start of transmitting a new packet). Although PUCCH is also used to transmit CQI, this embodiment focuses on PUCCH that transmits ACK / NACK. Although the PUCCH transmission timing is fixedly determined in this way, it may be set to another numerical value as described later. The base station apparatus determines whether the delivery confirmation information is ACK or NACK, and in the case of NACK, retransmits the packet again after the elapse of a predetermined period. For example, transmission of a retransmission packet starts 4 TTIs after receiving PUCCH (ACK / NACK). In this case, the radio resource used for ACK / NACK is determined as follows.

As described above, the physical downlink control channel (PDCCH) contains control information for a user multiple number, and each of them is associated with one or more control channel elements (CCE). In the illustrated example, control information for N users is associated with N control channel elements (CCE-1, ..., CCE-N). For the sake of simplicity, it is assumed that the control information for one user corresponds to one CCE, but this is not essential. Generally, the control information of one user is mapped to one or more CCEs. Furthermore, N PUCCH resources are secured in a one-to-one correspondence with the CCE for these N users. In the illustrated example, the x-th control channel element (CCE-x) and the x-th PUCCH resource (#x) are associated with each other on a one-to-one basis. Therefore, for example, when a PDSCH is received according to the downlink scheduling grant included in CCE-x, the ACK / NACK for the PDSCH is transmitted using the PUCCH of #x. By receiving and demodulating the PUCCH of #x, the base station device has succeeded in receiving the packet (ACK) or failed in receiving the packet by the destination user when the downlink scheduling grant was transmitted by CCE-x in the past. You can know (NACK). By maintaining a one-to-one correspondence between CCE-x and #x in this way, ACK / NACK can be transmitted properly without explicit signaling (which PUCCH should be used). It is not necessary to notify the signal on PDCCH each time.)

In the first operation example, such an operation is performed in both the new system and the old system. However, in the old system, the retransmission packet is transmitted after the transmission of the first packet (4TTI + 4TTI =) 8TTI, but in the new system, for example, the retransmission packet is transmitted after the transmission of the initial packet (2TTI + 4TTI =) 6TTI. To.

As shown in FIG. 8, in this case, there are concerns about collision from two points of view. For example, T₁It is assumed that PDSCH is sent to the user of the old system in the subframe indicated by, and the downlink scheduling grant is mapped to CCE-1. And T₂It is assumed that PDSCH is sent to the user of the new system in the subframe indicated by, and its downlink scheduling grant is also mapped to CCE-1. As described above, when the mapping position of the control information and the radio resource number of PUCCH are associated with each other on a one-to-one basis, both the old and new user devices try to transmit ACK / NACK with the same PUCCH (# 1). It ends up. In addition, there is a possibility that the transmission timings of the retransmission packets may collide.

Regarding the transmission timing of the retransmission packet, the round trip time (RTD) can be adjusted with each other in each of the old and new systems so as to avoid a collision. In the example in Figure 8, the old system is trying to set RTD = 8TTI and the new system is trying to set RTD to 6TTI, which avoids collisions by increasing the RTD of the old system by one subframe, as shown in Figure 9. Yes (assuming that the standard specifications of the old system allow changes to the RTD). Alternatively, the RTD of the new system may be changed. As shown in Fig. 10, even if the transmission timing of the retransmission packet is the same in the old and new systems, if there is enough resources to use the frequency division multiplexing method, the round trip time (RTD) It is not essential to change. In this way, collision of retransmitted packets can be easily avoided by adjusting the RTD period relatively between the old and new systems.

Next, consider the ACK / NACK collision. For convenience of explanation, the mobile station of the old system sends an ACK / NACK to the base station after 4 TTIs after receiving the physical downlink shared data channel (PDSCH), and the mobile station of the new system is the physical downlink shared data channel (PDSCH). After receiving PDSCH), ACK / NACK shall be transmitted to the base station after 2 TTI. As described above, the mapping position (CCE # x) of the control information (PDCCH) and the resource (#x) of the PUCCH are used so that the radio resource used for ACK / NACK transmission does not have to be signaled each time. In the meantime, a predetermined one-to-one correspondence was set. Therefore, while using the same rules in both the old and new systems, another device is required to avoid ACK / NACK collisions. For example, the following three methods (1) to (3) can be considered.

(1) In the old system, it is assumed that PDSCH of a certain subframe N is assigned to a certain user device UE-A, and the allocation information (control information) is mapped to CCE # 1 of PDCCH. In the new system, PDSCH of another subframe N + 2 is assigned to another user device UE-B, and the allocation information (control information) is mapped to CCE # 1 of PDCCH. The physical downlink shared channel (PDSCH) destined for each user device is properly transmitted in separate subframes. However, PUCCHs that transmit ACK / NACK collide.

In the first method, the scheduler of the base station configures a physical downlink control channel (PDCCH) so that such a collision does not occur in the first place. Specifically, first, scheduling for the above subframe N is performed. Then, when scheduling subframe N + 2, it is considered that the control information for allocating PDSCH to UE-A was mapped to CCE # 1 regarding PDSCH in subframe N. Therefore, for subframe N + 2, UE-B control information is mapped to a control channel element different from CCE # 1. In this way, the scheduler considers how the control information (PDCCH) was configured for the users of the old system in the preceding subframe when deciding the allocation of radio resources to the users of the new system for a certain subframe.

Scheduling is originally based on the circumstances of a particular subframe, but additional information about past subframes is needed to perform the above actions. Therefore, although the computational processing load of scheduling may increase slightly, ACK / NACK collisions can be effectively avoided.

(2) In the second method, the resources of the physical uplink control channel (PUCCH) are separately prepared for each of the old system and the new system.

In the example shown in Figure 11, resources for PUCCH are provided at both ends of the system bandwidth. As an example, 25 resource blocks (RB1 to RB25) are included in the 5MHz system band. Of these, the first and 25th resource blocks (RB1, RB25) are used exclusively for the PUCCH of the old system. The second and 24th resource blocks (RB2, RB24) will be used exclusively for PUCCH of the new system. In the illustrated example, # 0 and # 1 correspond to users of the old system, and # 2 and # 3 correspond to users of the new system.

By allocating PUCCH resources to each system in advance in this way, collisions between PUCCH resources can be reliably avoided.

(3) The third method does not impose a heavy computational burden on scheduling, and it is not necessary to secure resources separately for each system. In the third method, the PUCCH is code-multiplexed to avoid the above collision. That is, when ACK / NACK is transmitted in the same slot and frequency as described above, the ACK / NACK from the mobile station of the old system and the ACK / NACK from the mobile station of the new system are spread by different spreading codes. The code is multiplexed. Any appropriate code may be used from the viewpoint of distinguishing by code multiplexing. As an example, the sign may be determined as follows.

Figure 12 shows what code is used when mapping each of up to 18 ACK / NACK information (A / N # x) to any of the 18 mapping positions (CCE # x). Is shown. The code is specified by the Walsh code Index and the Cyclic Shift Indices. It will be clear that other code sequences may be used. In the illustrated example, three types of Walsh code sequences are prepared, and by cyclically shifting each sequence, six different codes are prepared for each sequence. For example, a spread code with a cyclic shift amount of 2 in the first sequence is used for A / N # 1 mapped to CCE # 9. In this way, by combining the information that specifies the code sequence and the information that specifies the shift amount and associating the combination with a specific control channel element, it is possible to tell the user device when and what code should be used with a small number of bits. You can notify.

For example, suppose that PDSCH of a certain subframe N is assigned to a certain user device UE-A, and the allocation information (control information) is mapped to CCE # 1 of PDCCH. In the new system, PDSCH of another subframe N + 2 is assigned to another user device UE-B, and the allocation information (control information) is mapped to CCE # 1 of PDCCH. In this case, both UE-A of the old system and UE-B of the new system are associated with the code of the cyclic shift amount of 4 in the first series (because both are related to CCE # 1). Therefore, if nothing is done, the signals will collide. Therefore, we will notify the user of the new system of another cyclic shift amount with a certain shift bit (some amount other than 4). The user of the old system configures PUCCH using the code of the cyclic shift amount of 4 in the first series according to the above rule. The user of the new system receives a shift bit from the base station and is informed that any quantity other than 4 (eg, 6) should be used as the cyclic shift quantity. Therefore, the user of the new system constitutes PUCCH with the code of the cyclic shift amount of 6 in the first series. As a result, each user simultaneously transmits PUCCH at the same frequency, but since they are code-spread with different codes, they are transmitted appropriately. This may be the diffusion code number. It may also be given as a relative value to the current value.

In this way, the user of the new system can be notified of an appropriate code with a small number of bits by notifying a certain shift bit in addition to the correspondence as shown in FIG.

&lt;<u style="single">4. Second example of operation-uplink data transmission</u>&gt; Next, the case where the physical uplink shared channel (PUSCH) is transmitted from the user device will be described.

In the example shown in FIG. 13, a physical downlink control channel (PDCCH) containing an uplink scheduling grant is transmitted from the base station equipment, and a physical uplink shared data channel (PUSCH) is transmitted from the user equipment 4 TTIs after the start of transmission. .. Further, 4 TTI after the start of PUSCH transmission, the base station apparatus notifies the user apparatus of the necessity of retransmission. In the system discussed in this discussion, the need for retransmission is: (a) When notified (by PDCCH) with the uplink scheduling grant, (b) When notified by PHICH There is. FIG. 13 shows the former case, and the latter case will be described later. PHICH indicates delivery confirmation information (ACK / NACK). In the system considered in this description, both cases (a) and (b) may be notified, or only (b) may be given. If both notifications are given, the necessity of retransmission notified by PDCCH is prioritized, and the ACK / NACK indicated by PHICH is ignored. Therefore, PHICH is used meaningfully in the case of (b).

Consider the case where retransmission is required in (a). In this case, the user device sends a retransmission packet using the resource specified by PDCCH. Since the uplink scheduling grant is notified, the retransmission packet is transmitted with a resource suitable for retransmission (a resource that is not necessarily the same as the resource of the initial packet). Both users of the new system and users of the old system can properly send retransmission packets according to the physical downlink control channel (PDCCH).

With reference to FIG. 14, consider the case where retransmission is required in (b). In this case, since there is no physical downlink control channel, the resource used for PHICH is unknown as it is. PHICH resources are determined as follows.

First, the base station equipment schedules the uplink, and each user equipment is allowed to transmit the uplink, and the physical downlink control channel (PDCCH) -the thick frame in the upper left of the figure-is transmitted from the base station equipment. Will be done. The user device demodulates the downlink control signal. The user device confirms whether or not the PDCCH addressed to the own device is included in the received PDCCH. If there is a PDCCH addressed to the own device, prepare for communication using the specified resource block. In the illustrated example, radio resources are allocated for the transmission of the physical uplink shared channel (PUSCH) -new packet-as follows:

Three resource blocks RB0 to RB2 are assigned from RB0 to the user device UE-1.

Four resource blocks RB3 to RB6 are assigned from RB3 to the user device UE-2.

Five resource blocks RB7 to RB11 are assigned from RB7 to the user device UE-3.

Four resource blocks RB12 to RB15 are assigned from RB12 to the user device UE-4.

Three resource blocks RB16 to RB18 are assigned from RB16 to the user device UE-5.

An uplink physical shared channel (PUSCH) is transmitted from each user device in such a resource block.

The base station apparatus receives the PUSCH from each user apparatus and determines the necessity of retransmission. The determination result is notified to each user device by PHICH. If no retransmission is required, delivery confirmation information indicating an acknowledgment (ACK) is provided. If a retransmission is required, delivery confirmation information indicating a negative response (NACK) is prepared. Delivery confirmation information is prepared for every user who has sent PUSCH. In the current example, since five users UE-1 to UE-1 to 5 are transmitting the upstream physical shared channel, delivery confirmation information for five users is prepared.

As for the resources for PHICH, only the total number of resource blocks is secured, and in the example of FIG. 14, 19 resources for PHICH (PHICH-# 0 to # 18) are prepared. Of these 19 resources, the resource corresponding to the youngest resource block assigned to each user device is used. Since the resource blocks are assigned to UE-1 in order from the resource block RB0, the delivery confirmation information of UE-1 is written to PHICH- # 0. Since the resource blocks were assigned to UE-2 in order from the resource block RB3, the delivery confirmation information of UE-2 is written to PHICH- # 3. Similarly, the delivery confirmation information of UE-3 is written in PHICH- # 7. UE-4 delivery confirmation information is written to PHICH-12. UE-5 delivery confirmation information is written to PHICH- # 16. PHICH- # 1 to # 19 prepared in this way are notified to each user device.

Each user device reads the PHICH associated with its own device from the downlink control signal. The read timing is 4 TTI after the start of transmission of a new packet (PUSCH) from the own device. Each user device remembers in which resource block the PUSCH was transmitted. When PUSCH is transmitted in the xth and subsequent resource blocks, the delivery confirmation information of the user is written in the xth PHICH (PHICH-x). Therefore, The user device UE-1 determines the necessity of retransmission by reading PHICH- # 0.

The user device UE-2 determines the necessity of retransmission by reading PHICH- # 3.

The user device UE-3 determines the necessity of retransmission by reading PHICH- # 7.

The user device UE-4 determines the necessity of retransmission by reading PHICH- # 12.

The user device UE-5 determines the necessity of retransmission by reading PHICH- # 16.

If no retransmission is required (in the case of ACK), the user device completes the transmission related to the process number and prepares for further communication. If retransmission is required (if it is NACK), the retransmission packet is transmitted 8 TTI after the start of transmission of the initial packet (4 TTI after reception of PHICH- # x). The radio resource for retransmission may be the same as the resource of the new packet, or may be different. In the latter case, it is predetermined how different resources will be used.

In this way, since the resource block used for the physical uplink shared channel (PUSCH) and the resource for PHICH corresponding to one-to-one are prepared, the base station device and the user device need no signaling. PHICH can be transmitted and received properly without.

FIG. 15 is a diagram for explaining the operation when the old system and the new system coexist. As mentioned above, the necessity of resending may be notified by PDCCH, or only PHICH may be notified without PDCCH (in this context, the term is defined so that PDCCH does not include PHICH). .). In the old system, as described above, the retransmission packet is transmitted 4 TTI after receiving PHICH (in the case of NACK). In the new system, a retransmission packet is sent 2 TTI after receiving PHICH (in the case of NACK). In the illustrated example, both the user of the old system and the user of the new system send the retransmission packet in the same subframe. However, when trying to secure resources for resending by the user of the old system, it is unclear whether the user of the new system will resend afterwards. Therefore, it is not easy to properly schedule all PUSCHs for both old and new systems without any conditions.

In this embodiment, as shown in the figure, resources (bandwidth) for the old system and resources for the new system are prepared separately. This will hinder the effective use of resources, but will ensure that PUSCH can be transmitted without collisions. First, the scheduler of the base station device schedules the resources reserved in the old system in a certain subframe. At a later point, the scheduler schedules the resources allocated to the new system in that subframe. In this case, if the resources reserved for the old system are surplus, the surplus may be used by the users of the new system.

&lt;<u style="single">5. Base station equipment</u>&gt; FIG. 16 shows a base station apparatus used in an embodiment of the present invention. FIG. 5 shows a scheduler 52, a low layer control channel generation unit 53, an upper layer control information generation unit 54, a broadcast information generation unit 55, a downlink data channel generation unit 56, a multiplexing unit 57, and an uplink control information extraction unit 58. ing.

The scheduler 52 schedules radio resources. Scheduling may be done by any suitable algorithm known in the art. As an example, scheduling may be performed by the maximum C / I method or the proportional fairness method. Downstream and / or uplink scheduling information is given to the low layer control channel generation unit 53. Since the scheduling information indicates the correspondence between the information to be transmitted and the frequency and time, the correspondence is also given to the multiplexing unit 57 as mapping information. The scheduler 52 also determines the data modulation method and channel coding rate applied to the data channel, and is given to the downlink data channel generation unit 56 as AMC information. When the first operation example (1) is performed, the scheduler 52 schedules the downlink so that the ACK / NACKs of the users of the old and new systems do not collide.

The low-layer control channel generation unit 53 prepares control information to be transmitted on the downlink L1 / L2 control channel, for example, and applies predetermined channel coding and data modulation to the control information to form an L1 / L2 control channel. Create a low layer control channel. When the first operation example (3) is performed, the shift bit information (information indicating the cyclic shift amount) is also included in the low layer control signal.

The upper layer control information generation unit 54 prepares information such as L3 control information and gives it to the downlink data channel generation unit 56.

The notification information generation unit 55 prepares notification information (BCH) to be notified to the user device in the cell and gives it to the downlink data channel generation unit 56.

Information such as that PUCCH resources are prepared separately for the old system and the new system and / or that PUSCH resources are prepared separately for the old system and the new system is used as upper layer control information or notified. It may be notified to the user apparatus as information.

The downlink data channel generation unit 56 generates the downlink data channel by receiving the user data, the upper layer control information, and the broadcast information, and performing data modulation and channel coding on the signal including them.

The multiplexing unit 57 multiplexes the low layer control channel and the downlink data channel. Multiplexing is generally done in terms of time division multiplexing and frequency division multiplexing.

The uplink control information extraction unit 58 extracts uplink control information from the signal received on the uplink and restores it.

&lt;<u style="single">6. User device</u>&gt; FIG. 17 shows a user device used in an embodiment of the present invention. FIG. 17 shows a low-layer control information restoration unit 61, a downlink data channel restoration unit 62, an uplink data channel generation unit 63, an ACK / NACK resource determination unit 64, and an ACK / NACK generation unit 65.

The low-layer control information restoration unit 61 decodes and demodulates the low-layer control channel received from the base station apparatus, and extracts control information. The control information includes scheduling information of the upper and lower links, packet numbers, puncture patterns, ACK / NACK for PDSCH, and the like.

The downlink data channel restoration unit 62 extracts the downlink data channel, demodulates and decodes it according to the downlink scheduling information, and restores the downlink data channel.

The uplink data channel generation unit 63 generates an uplink data channel according to the uplink scheduling grant. The uplink data channel creates a new or retransmission uplink data channel according to the retransmission control information (ACK / NACK) notified from the low layer control information restoration unit 61.

The ACK / NACK resource determination unit 64 determines which resource is used for ACK / NACK notification for each of the upper and lower links. The resources used to send an ACK / NACK to a physical downlink shared channel (PDSCH) are determined based on where in the PDCCH the control information for that PDSCH was mapped (CCE). The resource used to receive an ACK / NACK for the physical uplink shared channel (PUSCH) is determined based on in which resource block the PUSCH was transmitted. When the code for code multiplexing is specified by the series number and the cyclic shift amount, the information is also notified to the ACK / NACK resource determination unit 64.

The ACK / NACK generation unit 65 prepares delivery confirmation information (ACK or NACK) regarding PUSCH.

The present invention may be applied to any suitable mobile communication system used in an area where systems with different retransmission periods coexist. For example, the present invention may be applied to an HSDPA / HSUPA system W-CDMA system, an LTE system, an IMT-Advanced system, a WiMAX, Wi-Fi system, or the like.

Although the present invention has been described above with reference to specific examples, the examples are merely examples, and those skilled in the art will understand various modifications, modifications, alternatives, substitutions, and the like. .. Although explanations have been given using specific numerical examples in order to promote understanding of the invention, these numerical values are merely examples and any appropriate value may be used unless otherwise specified. Although explanations have been made using specific mathematical formulas to promote understanding of the invention, these mathematical formulas are merely examples and any appropriate mathematical formula may be used unless otherwise specified. The division of each explanatory matter is not essential to the present invention, and the matters described in two or more sections may be combined or combined as necessary. For convenience of explanation, the devices according to the embodiments of the present invention have been described with reference to functional block diagrams, but such devices may be implemented in hardware, software, or a combination thereof. The present invention is not limited to the above examples, and various modifications, modifications, alternatives, substitutions and the like are included in the present invention without departing from the spirit of the present invention.

<figref num="1">It is a figure which shows the outline of the mobile communication system.</figref><figref num="2">It is a figure which shows the breakdown of the air interface delay.</figref><figref num="3">It is a figure which shows the subframe structure.</figref><figref num="4">It is a figure which shows how PDCCH and PDSCH are mapped to a subframe.</figref><figref num="5">It is a conceptual diagram for explaining CCE.</figref><figref num="6">It is a figure which shows an example of PUCCH.</figref><figref num="7">It is a figure which shows how the necessity of resending is notified by PUCCH.</figref><figref num="8">It is a figure which shows how different channels of RTD are improperly multiplexed.</figref><figref num="9">It is a figure which shows how the different channels of RTD are appropriately multiplexed.</figref><figref num="10">It is a figure which shows how the different channels of RTD are appropriately multiplexed.</figref><figref num="11">It is a figure which shows how PUCCH resources are prepared separately for each of the old and new systems.</figref><figref num="12">It is a figure which shows how the code for code multiplexing is specified by a series number and a cyclic shift amount.</figref><figref num="13">It is a figure which shows the mode that the necessity of resending is notified by PDCCH.</figref><figref num="14">It is a figure which shows how PHICH is notified independently.</figref><figref num="15">It is a figure which shows how the channel of a different RTD is multiplexed.</figref><figref num="16">It is a figure which shows the base station apparatus used in one Example of this invention.</figref><figref num="17">It is a figure which shows the user apparatus used in one Example of this invention.</figref>

Code description

50 cells 100₁,100₂,100₃ User device 200 base station equipment 300 Upper node 400 core network 52 Scheduler 53 Low layer control channel generator 54 Upper layer control information generator 55 Notification information generator 56 Downstream data channel generator 57 Multiple parts 58 Uplink control information extraction unit 61 Low layer control information recovery unit 62 Downstream data channel restorer 63 Upstream data channel generator 64 ACK / NACK resource judgment unit 65 ACK / NACK generator