JP2009147750A - Wireless transmitter and wireless receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high-frequency diversity gain by making it possible to set a distance G on a frequency axis between two resource blocks, to which a transmission signal is to be assigned, into a larger value. <P>SOLUTION: The wireless transmitter comprises: a transmission signal generating section 11 for generating a transmission signal; an assignment section 17 for assigning the transmission signal to two resource blocks spaced away by a distance G on a frequency axis; a setting section 14 for setting a natural number (not including 0) smaller than W×(1-1/(2M))+1, wherein the total number of resource blocks in a wireless communication system is defined as W, and a ratio of the maximum number of resource blocks to be used for the assignment in the W is defined as 1/M; and a transmission section 18-19 for transmitting an RF signal containing the two resource blocks. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radio transmitter and a radio receiver, and more particularly to assignment of a transmission signal to a resource block.

  In a wireless communication system using Orthogonal Frequency Division Multiple Access (OFDMA), users are multiplexed by assigning subcarriers generated by OFDMA to a plurality of users. In 3GPP-LTE, a method of allocating users in units called resource blocks in which 12 subcarriers are grouped is being studied.

  Furthermore, a method of allocating two resource blocks (resource block pairs) separated on the frequency axis per user is being studied. In general, since the correlation between channels decreases as the distance in the frequency direction increases, frequency diversity gain can be obtained by performing wireless communication using such a resource block pair, and as a result, reception performance is improved.

  When such an allocation method is used, it is generally necessary to notify the receiving side of a control signal representing a distance G on the time axis between two resource blocks to which a transmission signal is allocated. When such a control signal is notified, the overhead related to control increases. Therefore, in 3GPP-LTE, a method of using a value determined in advance in the system for the distance G is being studied. This eliminates the need to send a separate control signal, thereby reducing the overhead associated with control.

  On the other hand, as shown in Non-Patent Document 1, considering that a plurality of system bandwidths are defined in 3GPP (Third Generation Partnership Project) -LTE (Long Term Evolution), it is associated with the system bandwidth. Thus, a method for determining the distance G has been studied. That is, when the system bandwidth of the wireless communication system that has started communication is known from the transmission side to the reception side, the distance G is determined in association with this. By doing so, the receiving side can know G from the system bandwidth notified in advance without requiring a control signal, and can set G suitable for each system bandwidth. .

In general, it is known that the frequency diversity gain increases as G increases. However, it is difficult to set a large G when the system bandwidth is small. Therefore, for example, a small G can be used when the system bandwidth is small, and a large G can be used to increase the frequency diversity gain when the system bandwidth is large.
http://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_51/Docs/R1-074602.zip, "Downlink VRB email reflector summary", Motorola P1's "For example, the default spacing between PRBs used for a DVRB Down of "could be a fixed function of system bandwidth."

  In the related art as shown in Non-Patent Document 1, if G is set in accordance with the system bandwidth by associating G with the system bandwidth, it is difficult to set G to a value larger than half of the system bandwidth. This is because the number of users that can be multiplexed is limited when G is a value greater than or equal to the system bandwidth. As a result of the fact that the value of G cannot be set large, there has been a problem that the conventional technology sometimes fails to obtain a sufficient frequency diversity gain.

  An object of the present invention is to provide a radio transmitter capable of obtaining a higher frequency diversity gain by enabling the distance G on the frequency axis between two resource blocks to which a transmission signal is assigned to be set to a value larger than that of the prior art. It is to provide a wireless receiver.

  According to the first aspect of the present invention, a transmission signal generation unit that generates a transmission signal, an allocation unit that allocates transmission signals to two resource blocks that are separated by a distance G on the frequency axis, and a total resource of the radio communication system Assuming that the number of blocks is W and the ratio of the maximum number of resource blocks used for the allocation to W is 1 / M, a natural number (excluding 0) smaller than W × (1-1 / (2M)) + 1 is used. There is provided a wireless transmitter comprising: a setting unit configured as G; and a transmission unit that transmits an RF signal including the two resource blocks.

  According to the second aspect of the present invention, a transmission signal generation unit that generates a transmission signal, and an allocation unit that allocates transmission signals to two resource blocks that are separated by a distance G on the frequency axis and different positions on the time axis, A natural number smaller than W × (1-1 / (2M)) + 1, where W is the total number of resource blocks in the wireless communication system and 1 / M is the ratio of the maximum number of resource blocks used for the allocation to W. There is provided a wireless transmitter comprising: a setting unit that sets G as 0 (not including 0) and a transmission unit that transmits an RF signal including the two resource blocks.

  The radio transmitter according to the first or second aspect of the present invention includes a control including first information indicating that the allocation is used in the allocation unit and second information indicating one of the two resource blocks. A control signal generation unit that generates a signal may be further included, and the transmission unit may further transmit the control signal.

  In the wireless transmitter according to the second aspect of the present invention, first information indicating whether or not the assignment is used by the assigning unit, and the transmission signal of the two resource blocks is assigned earlier in time. A control signal generation unit that generates a control signal including second information indicating the other resource block, and the transmission unit may further transmit the control signal.

  A radio transmitter according to a second aspect of the present invention provides first information indicating whether or not the allocation is used by the allocation unit, second information indicating one of the two resource blocks, and the second information And a control signal generating unit that generates a control signal including third information indicating whether the transmission signal is allocated earlier or later in time to the resource block indicated by A control signal may be transmitted.

  In the wireless transmitter according to the second aspect of the present invention, first information indicating whether or not the assignment is used by the assigning unit, and the transmission signal of the two resource blocks is assigned earlier in time. Second information including a first index indicating a resource block, a resource block indicated by a second index obtained by adding the distance to the first index, and a resource block indicated by a third index obtained by subtracting the distance from the first index It may further comprise a control signal generation unit that generates a control signal including fourth information indicating to which the transmission signal is allocated, and the transmission unit may further transmit the control signal.

  According to a third aspect of the present invention, a receiving unit that receives an RF signal transmitted from a wireless transmitter according to the first or second aspect and obtains a received signal, and selects the two resource blocks from the received signal And a demodulator that demodulates the two resource blocks and reproduces a transmission signal.

  According to a fourth aspect of the present invention, a receiving unit that receives the RF signal and obtains a received signal, and when the first information is notified, the two resources and the two resources from the received signal by the G Provided is a radio receiver comprising a selection unit for selecting a block and a demodulation unit for demodulating the two resource blocks.

According to a fifth aspect of the present invention, a receiving unit that receives the RF signal and obtains a received signal;
A selector that selects the two resource blocks from the received signal according to the second information, the third information, and the G when the first information is notified; and a demodulator that demodulates the two resource blocks. A wireless receiver is provided.

  According to a sixth aspect of the present invention, a receiving unit that receives the RF signal and obtains a received signal; and when the first information is notified, the received signal is received by the second information, the fourth information, and the G A radio receiver comprising: a selection unit that selects the two resource blocks from; and a demodulation unit that demodulates the two resource blocks.

  According to the present invention, since the distance G on the frequency axis between two resource blocks to which a transmission signal is assigned can be set to a value larger than that in the prior art, a higher frequency diversity gain can be obtained. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
<Wireless transmitter>
As shown in FIG. 1, the wireless transmitter according to the first embodiment of the present invention includes a transmission signal generation unit 11, a system bandwidth setting unit 12, a maximum communication bandwidth ratio setting unit 13, a distance setting unit 14, It has an allocation control unit 15, a signal allocation unit 17, an RF transmission unit 18, and an antenna 19.

  The present embodiment is directed to an OFDMA wireless communication system including a wireless base station and a large number of wireless terminals accommodated by the wireless base station, and the transmitter of FIG. 1 is provided in the wireless base station in the wireless communication system. That is, the transmitter is used for downlink transmission from the radio base station to the radio terminal.

  The transmission signal generator 11 generates a transmission signal (data signal to be transmitted). The transmission signal is input to the signal allocation unit 17. In the signal allocation unit 17, transmission signals are allocated to two resource blocks (referred to as resource block pairs) separated by a distance G on the frequency axis according to a predetermined allocation method under the control of the allocation control unit 15. A resource block is a transmission unit composed of a set of a plurality of subcarriers (for example, 12 subcarriers in 3GPP-LTE).

  In the distance setting unit 14, a value of the distance G required by the allocation control unit 15 and the signal allocation unit 17 is set based on information from the system bandwidth setting unit 12 and the maximum bandwidth ratio setting unit 13. The two resource blocks to which the transmission signals are allocated are input to the RF transmission unit 18 and transmitted by the RF transmission unit 18 by performing processing such as digital-analog conversion, frequency conversion (up-conversion), and power amplification, for example. An RF signal is generated. The generated transmission RF signal is transmitted by the antenna 19.

  From the system bandwidth setting unit 12 and the maximum bandwidth ratio setting unit 13, system bandwidth information and maximum communication bandwidth ratio information are output and input to the distance setting unit 14 and also to the transmission signal generation unit 11. The The system bandwidth information and the maximum communication bandwidth ratio information are notified from the transmission signal generation unit 11 to the wireless receiver through the signal allocation unit 17, the RF transmission unit 18, and the antenna 19 in a timely manner.

Next, an outline of a method for setting the distance G in the distance setting unit 14 will be described.
In this embodiment, when the total number of resource blocks in the wireless communication system is W and the ratio of the maximum number of resource blocks used in the allocation method to the total resource block number W is 1 / M, the distance setting unit 13 A natural number (not including 0) smaller than x (1-1 / (2M)) + 1 is set as the distance G.

  Here, the total resource block number W is a value called a system bandwidth in the wireless communication system, and is given to the distance setting unit 14 by the system bandwidth setting unit 12. On the other hand, 1 / M is information indicating the ratio of the maximum number of resource blocks (herein referred to as the maximum communication bandwidth) used for communication out of the total number of resource blocks (system bandwidth) W, so the maximum communication bandwidth ratio This is called information, and is given to the distance setting unit 14 by the maximum communication bandwidth setting unit 13.

  In this way, by setting the distance G in consideration of the maximum communication bandwidth ratio 1 / M in addition to the system bandwidth W, the distance G is determined only from the system bandwidth as in the prior art disclosed in Non-Patent Document 1. It is possible to set G to a larger value compared to the determined method. As a result, it is possible to obtain a frequency diversity gain higher than that of the prior art, and an effect of improving the reception performance can be obtained.

<Wireless receiver>
On the other hand, the radio receiver according to the first embodiment of the present invention corresponding to the radio transmitter of FIG. 1 includes an antenna 21, an RF receiver 22, a signal selector 23, and a distance setting unit 24 as shown in FIG. A reception signal demodulator 25, a system bandwidth information acquisition unit 26, and a maximum communication bandwidth ratio information acquisition unit 27.

  As described above, the present embodiment is directed to an OFDMA wireless communication system including a wireless base station and a large number of wireless terminals accommodated by the wireless base station, and the receiver of FIG. 2 is used as a wireless terminal in the wireless communication system. It is provided and used for downlink reception.

  An RF signal (OFDM signal) transmitted from the transmitter in FIG. 1 is received by the antenna 21 to obtain a received RF signal. The received RF signal from the antenna 21 is subjected to processing such as voltage amplification, frequency conversion (down-conversion), and analog-digital conversion, for example, by the RF reception unit 22 to generate, for example, a baseband reception signal.

  A reception signal from the RF reception unit 22 is input to the signal selection unit 23, and two resource blocks to which a transmission signal is assigned are selected based on the distance G set by the distance setting unit 24. The selected two resource blocks are demodulated by the reception signal demodulator 25, whereby the transmission signals (data signals) assigned to the two resource blocks are reproduced.

  In the system bandwidth information acquisition unit 26, the information on the system bandwidth W notified from the transmitter in FIG. 1 is acquired from the output of the received signal demodulation unit 25. In the maximum communication bandwidth ratio information acquisition unit 27, the information of the aforementioned maximum communication bandwidth ratio 1 / M notified from the transmitter of FIG. 1 is acquired from the output of the reception signal demodulation unit 25. In the distance setting unit 24, a natural number (not including 0) smaller than W × (1-1 / (2M)) + 1 is set as the distance G based on the system bandwidth information and the maximum communication bandwidth information. . Information on the set distance G is given to the signal selection unit 23, and two resource blocks separated by the distance G on the frequency axis upon selection of the distance G are selected.

(Overview of how to derive G from W and M)
The system bandwidth of the maximum number of resource blocks used in the system bandwidth (total resource block number W) of the wireless communication system and the method of assigning transmission signals to two resource blocks separated by a distance G on the frequency axis (referred to as the assignment method) A method for determining the distance G from the ratio 1 / M with respect to the width W will be described in detail with reference to FIGS. The system bandwidth W represents the number of resource blocks that can be used in the wireless communication system. Of all the resource blocks, the ratio that can be allocated by the allocation method is represented by 1 / M.

  3 to 10 show how transmission signals are allocated to resource blocks, and 15 resource blocks shown in a square are arranged along the horizontal frequency axis. Each cell representing a resource block is assigned a number indicating the position of the resource block on the frequency axis, and the resource block with the number n is referred to as an nth resource block.

  Each resource block includes a plurality of (for example, 12) subcarriers. A resource block to which a line is connected is a block to which a transmission signal is assigned, and a three-digit reference number represents a set of two resource blocks (resource block pair) to which the transmission signal is assigned. For example, reference numeral “101” in FIG. 3 represents a pair of a first resource block and a ninth resource block.

  3 to 6 are cases where W = 15, FIG. 3 is M = 1, G = 8, FIG. 4 is M = 2, G = 12, FIG. 5 is M = 3, G = 13, and FIG. M = 4 and G = 14. 7 to 10 show the case where W = 25, FIG. 7 shows M = 1, G = 13, FIG. 8 shows M = 2, G = 19, FIG. 9 shows M = 3, G = 21, and FIG. M = 4 and G = 22.

  Information on W and M is notified in advance from the transmitter to the receiver as shown in FIGS. The notification of W and M information may be performed only once, for example, when communication is started, or may be performed periodically at a certain cycle. When performing regular notification, it is desirable that the period is longer than the cycle for notifying a flag and an index, which will be described later. By doing so, it is possible to reduce the overhead associated with the control.

  The receiver can calculate the number of resource blocks that can be used in the allocation method by using W and M notified from the transmitter in this way. However, W and M are natural numbers (not including 0), but W / M may not be an integer depending on the values of W and M. Further, in order to use the allocation method, multiple resource blocks of 2 are required.

Considering these, the number of resource blocks that can be used in the allocation method can be expressed by the following equation.
Floor (W / (2M)) × 2 (1)
However, Floor (X) represents the largest integer below X. Even if W and M are natural numbers (not including 0), the value of equation (1) may be 0. That is, the value of the formula (1) is an integer of 0 or more. A value of 0 in equation (1) indicates that there is no resource block that can be used for the allocation method.

  In this allocation method, a transmission signal is allocated to a resource block pair, that is, two resource blocks. Therefore, according to the equation (1), the floor (W / (2M)) resource blocks and the floor (W / (2M)) resource blocks can be paired and used in the allocation method. In order to dispose resource block pairs as far as possible on the frequency axis, each floor (W / (2M)) resource blocks may be arranged at both ends of the frequency axis.

  For example, when W = 15 and M = 1, Floor (15 / (2 × 1)) = 5. Therefore, using resource blocks 1 to 7 and resource blocks 9 to 15 as shown in FIG. Seven resource block pairs 101 to 107 may be configured. Further, for example, when W = 15 and M = 2, Floor (15 / (2 × 2)) = 3. Therefore, using resource blocks 1 to 3 and resource blocks 13 to 15 as shown in FIG. Three resource block pairs 201 to 203 may be configured.

Thus, the value of G when two resource blocks are arranged at the maximum on the frequency axis is calculated as the following equation (2).
(W-Floor (W / (2M)) × 2) + Floor (W / (2M))
= W-Floor (W / (2M))
= Ceil (WW / (2M))
= Ceil (W (1-1 / (2M))) (2)
However, Ceil (X) represents the smallest integer equal to or greater than X.

  If G is set to a value less than or equal to Ceil (W (1-1 / (2M))) calculated in this way, that is, a value less than W (1-1 / (2M)) + 1, then the floor is assigned to the allocation method. It can be seen that (W / (2M)) × 2 resource blocks can be used.

  In the prior art, since the distance G is set considering only W, it is necessary to set the value of G to Ceil (W / 2) or less. On the other hand, when the transmission method according to the first embodiment is used, the value of G may be set to Ceil (W (1-1 / (2M))) or less, and M is larger than 1. In addition, G can be set to a value larger than that of the prior art.

  For example, in the case of W = 15, in the prior art, assuming that the allocation is as shown in FIG. On the other hand, according to the first embodiment, when M = 2, as shown in FIG. 4, G = 12. Similarly, when M = 3, G = 13 as shown in FIG. 5, and when M = 4, G = 14 as shown in FIG.

  On the other hand, even in the case of W = 25, for example, in the prior art, G can be set only to 13 at the maximum assuming that the allocation is as shown in FIG. According to the embodiment, when M = 2, G = 19 as shown in FIG. 8, when M = 3, G = 21 as shown in FIG. 9, and when M = 4, as shown in FIG. Can be G = 22 as shown in FIG.

  Such association of W, M, and G can be performed by the table shown in FIG. 11 correspond to FIGS. 3 to 10, respectively. The table in FIG. 11 is shared in advance between the transmitter and the receiver. Specifically, a memory holding a table as shown in FIG. 11 is prepared in the distance setting unit 14 in FIG. 1 and the distance setting unit 24 in FIG. By doing so, the value of G used in the allocation method can be known from W and M. That is, it becomes possible to know G on the receiver side without increasing the control overhead.

  As described above, according to the first embodiment, it is possible to set a larger G than in the conventional technique. As a result, it is possible to obtain a frequency diversity gain higher than that of the prior art, and the effect of improving the reception performance can be obtained.

  Next, a method for associating G with W and M will be described in more detail. As a method of association, (a) a method of setting a maximum value to G as described below, (b) a method of setting a value smaller than the maximum value by X by (b) G, and (c) limiting G to less than a threshold value There is a way to do it.

(A) A method of setting a maximum value for G;
As described using Expression (2), the value of the distance G is set to a value equal to or less than Ceil (W (1-1 / (2M))), that is, a value less than W (1-1 / (2M)) + 1. If set, the number of resource blocks required for the allocation method defined by W and M can be secured. Therefore, when priority is given to increasing the frequency diversity gain, it is desirable that G be a maximum natural number (not including 0) less than W (1-1 / (2M)) + 1. For example, as shown in the table of FIG. 11, if G is associated with W and M, the maximum value that can be set for each combination of W and M can be used for G.

(B) A method of setting a value smaller than the maximum value by X by G;
When G is set according to the table of FIG. 11, the degree of freedom in scheduling decreases. The decrease in the degree of freedom of scheduling means that the number of patterns that can be allocated is limited when the number of resource blocks that use the allocation method increases.

  When W = 3 and M = 3, G can be set to 13 at the maximum. If G is determined according to this, when the number of resource blocks used for the allocation method is 4, only the allocation method shown in FIG. 5 has a pattern. That is, for example, in the allocation method that does not use the allocation method, the 15th resource block in FIG. 5 cannot be used.

  In order to improve the degree of freedom of scheduling, the value of G may be set to a value somewhat smaller than W (1-1 / (2M)) + 1. For example, when W = 3 and M = 3, G can be set to a maximum of 13. However, if G is set to a smaller value, for example, G = 11, the degree of freedom of scheduling is improved, and FIG. It is possible to take several patterns as shown in FIG.

  Thus, even when the value of the distance G is set to be relatively small, according to the present embodiment, it is still possible to set the value of G to be larger than that of the prior art. Specifically, in the prior art, when W = 3, as shown in FIG. 3, G can only be set to 8 at the maximum, whereas in this embodiment, G is set to 11. be able to.

Furthermore, in the prior art, it is necessary to set G to a value smaller than 8 when considering the degree of freedom of scheduling. Considering that both the prior art and the present embodiment have the same scheduling freedom, it is possible to set a larger G in the present embodiment than in the prior art. For example, when considering setting G to a small value by 2 in order to increase the degree of freedom in scheduling, G = 6 in the case of W = 15 and G = 11 in the case of W = 25 in the prior art. However, in this embodiment, even when W = 15, G = 11 as shown in FIG. In this way, according to the present embodiment, it is possible to set a larger G than in the prior art.
When the distance G is set to a value smaller by X than the value of Ceil (W (1-1 / (2M))), the value of X may be changed for each W. In general, as the value of G increases, the frequency diversity gain increases. However, as G increases, the degree of increase in frequency diversity gain with respect to an increase in G decreases. Since the value of Ceil (W (1-1 / (2M))) increases as W increases and M increases, for example, X is set small when W is small, and X when W is large is set. For example, X may be set small when M is small, and X may be set large when M is large. By doing so, it is possible to effectively improve the degree of freedom of scheduling without significantly reducing the frequency diversity gain.

(C) a method of limiting G to less than a threshold;
As described above, the frequency diversity gain generally increases as the value of the distance G increases. However, as G increases, the degree of increase in frequency diversity gain with respect to an increase in G decreases. Due to this effect, even if G is increased beyond a certain value, it is possible that the frequency diversity gain hardly increases. On the other hand, increasing the value of G leads to a reduction in scheduling freedom.

Therefore, by setting G so as not to exceed a certain threshold value TH, it is possible to effectively increase the degree of freedom of scheduling without substantially reducing the frequency diversity gain. For example, as described above, it is desirable to set G = Ceil (W (1-1 / (2M))) in order to obtain the maximum frequency diversity gain.
G = Min (TH, Ceil (W (1-1 / (2M)))) (3)
G may be set as follows.

  Specifically, the value of G when TH is set to 15 in the example of FIG. 11 is as shown in FIG. In FIG. 14, it can be seen that the value of G when W = 25 and M = 2, 3, and 4 is limited to 15 by the threshold value TH. Further, for example, as shown in FIG. 15, even when setting a value somewhat smaller than Ceil (W (1-1 / (2M))) to G is considered, in addition to this, the upper limit of G is further increased by the threshold value TH. Can also be set.

(About the relationship between the two distances G1 and G2)
As described with reference to FIGS. 11, 14, and 15, in this embodiment, by defining G in association with W and M, it is possible to set a larger G than in the prior art. . More specifically, as shown in Expression (2), as M increases, G can be set larger. Therefore, in order to increase the frequency diversity gain, it is desirable that G increases as M increases.

  More specifically, G = G1 is associated with the same W = W1 and M = M1, and G = G2 is associated with W = W2 and M = M2. If W1 = W2 and M1 <M2, it is desirable to set G1 <G2.

However, when the upper limit of G is set by the threshold TH as described above, G cannot take a value larger than a certain value, so that even if M is different, G can be set to a different value. It can be difficult. In such a case, it is sufficient if G1 ≦ G2 is satisfied. Similarly, when W is very small, it may be difficult to set G to a different value. For example, if the maximum value of G is calculated based on Equation (2) for each of W = 6 and M = 2 and W = 6 and M = 3,
Ceil (6 (1-1 / (2 × 2))) = 5
Ceil (6 (1-1 / (2 × 3))) = 5
And become the same value. In such a case, it is sufficient if G1 ≦ G2 is satisfied.

(G is set to a power of 2)
In consideration of mounting the transmitter and the receiver in hardware, as shown in FIG. 16, the distance G is set to the maximum power of 2 that does not exceed the upper limit expressed by the equation (2). May be. In the example of FIG. 16, G is set to 2 ³ = 8 and 2 ⁴ = 16. In this way, by setting G to a power of 2, implementation in hardware using binary numbers can be simplified.

(Second Embodiment)
<Wireless transmitter>
FIG. 17 shows a wireless transmitter according to the second embodiment of the present invention, and a control signal generator 16 is added to the transmitter of FIG. The control signal generation unit 16 includes a flag (first information) indicating that an allocation method for allocating transmission signals to two resource blocks separated by G on the frequency axis is used, and two resource blocks allocated by the allocation method. In order to notify the receiver of the index indicating the one (second information), a control signal including these flags and the index is generated.

  Further, in addition to the flag and the index, the control signal generation unit 16 may generate a control signal further including a phase or a sign in order to notify a phase (third information) or a sign (fourth information) described later. .

  The control signal generated by the control signal generation unit 16 is allocated over any resource block or a plurality of resource blocks in time by the signal allocation unit 17 under the control of the allocation control unit 15, and the RF transmission unit 18 and the antenna 19 and sent to the receiver.

<Wireless receiver>
On the other hand, FIG. 18 shows a wireless receiver corresponding to the wireless transmitter of FIG. 17, and a control signal demodulator 28 is added to the receiver shown in FIG. In the signal selection unit 23, a control signal included in a reception signal obtained from the antenna 21 via the RF reception unit 22 is selected and demodulated by the control signal demodulation unit 28, whereby the above-described flag and index, and also the phase or sign Is played. The reproduced flag and index, as well as the phase or sign, are sent to the signal selector 23.

  In the signal selection unit 23, based on the distance G set by the distance setting unit 24 and the flag and index from the control signal demodulation unit 28, two resource blocks (resource block pairs) separated from the received signal by a distance G on the frequency axis. ) Are separated and given to the received signal demodulator 25. As a result, the received signal demodulator 25 demodulates the two resource blocks, and the transmission signals (data signals) assigned to the two resource blocks are reproduced. Hereinafter, this embodiment will be described in more detail.

(Details of transmission / reception methods using flags and indexes)
As described above, the transmission signal is assigned to two resource blocks separated by G on the frequency axis. For example, in the resource block pair 201 shown in FIG. 4, the first resource block and the thirteenth resource block are paired, and a transmission signal is assigned thereto.

  Thus, in order to take out the transmission signal assigned to the resource block pair at the receiver, it is necessary to notify the receiver of information regarding the position of the resource block to which the transmission signal is assigned to the receiver. In the second embodiment, as such information, a flag indicating that the allocation method is applied in the transmitter and an index indicating one of the resource blocks allocated by the allocation method are used.

  The flag has information indicating whether or not the allocation method is applied. For example, if the flag is 1-bit information, 0 indicates that the allocation method has not been applied, and 1 indicates that the allocation method has been applied.

  The index indicates either resource block of the resource block pair to which the transmission signal is allocated. For example, in the case of the resource block pair 201 in FIG. 4, the index indicates either the first resource block or the thirteenth resource block.

  In the receiver of FIG. 18, it is possible to extract the assigned transmission signal by using these flags and indexes. For example, when the flag is 1 and the index is 1, it can be seen that a transmission signal is assigned to the first resource block and a pair with another resource block that is paired with the first resource block.

  Here, as described above, the value of G is determined by W and M, and in this example, G = 12, so that it is understood that the resource block paired with the first resource block is the thirteenth resource block. Also, when the flag is 1 and the index is 13, there is no 25th source block that is increased from G by 13 from 13, so the 13th block is paired with the first resource block that is decreased from 13 by G = 12. It can be seen that In this way, when G is a value that is half or more of the total number W of resource blocks of the wireless communication system, the transmission signal is assigned only by an index indicating one of the resource blocks of the resource block pair to which the flag and the transmission signal are assigned. It is possible to specify a given resource block pair.

  On the other hand, care must be taken when G is less than half of the total resource block number W of the wireless communication system. For example, when G = 3 and the index is 8, it cannot be specified whether the resource block paired with the eighth resource block is the fifth resource block or the eleventh resource block. In order to remove such uncertainty, for example, a smaller one of the indexes of the resource block pair may be notified in advance. In this way, for example, in the above example, it can be determined that the resource block paired with the eighth resource block of index 8 is the eleventh resource block.

(Method 1 for dividing resource blocks on the time axis)
In the description so far, the case where resource block pairs separated by a distance G on the frequency axis are arranged in the same time domain (that is, the same position on the time axis) has been described. That is, they may exist at different positions on the time axis.

  FIG. 19 shows an example. For example, a resource block 1101 and a resource block 1104 having a different position on the time axis from the resource block 1101 form one resource block pair. Similarly, the resource block 1102 and the resource block 1103 having different positions on the time axis form one resource block pair.

  Further, for example, as shown in FIG. 20, one resource block in FIG. 19 may be divided into two on the time axis to form a resource block pair 1201 and a resource block pair 1202. Thus, even when one resource block is divided, the amount of resource blocks occupied by one resource block pair does not change.

  By the way, when resource block pairs are formed by combining resource blocks at different positions on the time axis as shown in FIG. 19 and FIG. 20, care must be taken when notifying the method of assigning transmission signals to resource blocks. . For example, when the flag is 1 and the index is 1 in the example of FIG. 19, the resource block pair to which the transmission signal is assigned is a pair of the first resource block 1101 and the ninth resource block 1104 at a certain position on the time axis. Therefore, there is a possibility of both the ninth resource block 1102 and the first resource block 1103 as a pair at different positions on the time axis.

  In such a case, for example, the index may be notified of the index of the resource block to which the transmission signal is allocated first (first) in time. That is, when the flag is 1 and the index is 1 in the example of FIG. 19, among the first resource blocks 1101 and 1103 having the index 1 at different positions on the time axis, the transmission signal is first transmitted to the resource block 1101. Therefore, a pair of resource blocks 1101 and 1104 is made to correspond to index 1. Further, when the flag is 1 and the index is 9 in the example of FIG. 19, the first transmission signal is transmitted to the resource block 1102 among the ninth resource blocks 1102 and 1104 whose index is 9 at different positions on the time axis. Therefore, the pair of resource blocks 1102 and 1103 may correspond to the index 9.

  Similarly, in the example of FIG. 20, when the flag is 1 and the index is 1, the resource block pair 1201 corresponds to the index 1, and when the flag is 1 and the index is 9, the resource block pair 1202 is the index 9 It should be made to correspond to.

  In this way, when resource blocks at different positions on the time axis are combined into a resource block pair, the information amount of the control signal can be reduced by notifying the index of the resource block to which the transmission signal is assigned in time. Without increasing, it is possible to notify the radio communication apparatus side of the transmission signal allocation method to the resource block.

(Method 2 for dividing a resource block on the time axis (when G ≦ W / 2))
On the other hand, further caution is required when the total number W of source blocks in the wireless communication system is a value greater than or equal to twice G. For example, in the example of FIG. 20, the description has been made assuming that the total number of resource blocks W is 15, but consider the case where W is 20, for example, as shown in FIG. 21.

  In the example of FIG. 21, when the flag is 1 and the index is 9, the resource block pair to which the transmission signal is assigned is both the resource block 1301 and 1304 pair 1305 and the resource block 1302 and 1303 pair 1306. there is a possibility. In such a case, in this embodiment, additional information is required to notify the transmission signal allocation to the resource block from the transmitter to the receiver.

  For example, the index indicates the smaller value of the resource block pair to which the transmission signal is assigned, and additionally indicates whether the transmission signal is assigned to the resource block indicated by the index first or later in time. The third information (this is called a phase) may be notified from the transmitter to the receiver.

  Specifically, in the example of FIG. 21, when the flag is 1, the index is 1, and the phase is 0, the resource block pair 1305 corresponds, and when the flag is 1, the index is 1, and the phase is 1, the resource Block pair 1306 corresponds. Further, in the example of FIG. 21, when it is desired to pair the resource block 1302 and the resource block 1307, the flag may be set to 1, the index may be set to 9, and the phase may be set to 0.

  In yet another method, an index (denoted as I) indicates a resource block (I-th resource block) at a previous position on the time axis of a resource block pair to which a transmission signal is assigned. Then, a transmission signal is allocated to an I-th resource block and an I + G resource block (I + G resource block) obtained by adding G to I, or an I-G resource block obtained by subtracting G from I-th resource block. 4th information (this is called a signature) which shows whether a transmission signal is allocated to (I-G resource block) is notified to a receiver from a transmitter. That is, when the sign is 0, the resource block of index I and the resource block of index I + G make a pair, and when the sign is 1, the resource block of index I and the resource block of index IG make a pair. Make it.

  Specifically, in the example of FIG. 21, when the flag is 1, the index is 1, and the sign is 0, the resource block pair 1305 corresponds, and when the flag is 1, the index is 9, and the sign is 1, the resource block Pair 1306 corresponds. Further, when it is desired to pair the resource block 1302 and the resource block 1307, the flag may be set to 1, the index may be set to 9, and the sign may be set to 0.

  These methods are the same even when one resource block is divided into a plurality on the time axis as shown in FIG. That is, when the total number W of source blocks in the wireless communication system is a value greater than or equal to twice G, a phase or sign is further notified from the transmitter together with the flag and index to the resource block pair. A transmission signal allocation method can be shown.

(About control signals for sending flags and indexes)
The flag, index, phase, or sign information described so far may be collected as a control signal and notified from the transmitter to the receiver. The control signal may be transmitted once, for example, every time a resource block pair is transmitted.

  For example, as described with reference to FIGS. 19, 20, and 27, when a resource block pair is formed by two resource blocks having different positions on the time axis, one control signal is provided for each resource block pair. Can be sent. Here, for example, the length of time for two resource blocks is called a subframe. For example, as shown in FIG. 22, one control signal 1000 may be inserted for each subframe.

  In this way, the receiver first obtains the flag and index, and, if necessary, the phase or sign information by demodulating the control signal 1000, so that the transmission signal allocation method for the resource block pair can be obtained. I can know. Control signal 1000 may be arranged at the beginning of the subframe. In addition, a transmission signal is not assigned to an area of the resource block to which the control signal 1000 is assigned. Even in such a case, it is desirable that the amount of resources included in each resource block pair is the same. In other words, it is desirable that the area occupied by the control signal 1000 is evenly distributed among the resource block pairs.

<Application example to 3GPP-LTE>
Hereinafter, a method for setting the distance G when the first or second embodiment is applied to 3GPP-LTE will be described with specific numerical examples.

(Method of setting G for each system bandwidth)
Another example in which G is associated with W and M will be described with reference to FIGS. 23, 24, and 25. 11, FIG. 14, FIG. 15 and FIG. 16, the case where W is only 15 and 25 has been described. On the other hand, in 3GPP-LTE, six values of 6, 15, 25, 50, 75, and 100 have been studied as W values. FIGS. 23, 24, and 25 show an example in which G is associated with each of the combinations of all these W values and M = 1, 2, 3, and 4. FIG.

  FIG. 23 shows an example in which the maximum natural number (not including 0) that can be set based on the upper limit value of Expression (2) is the value of G, and corresponds to the example of FIG. FIG. 24 further applies an upper limit of G by setting the threshold value TH to 25, and corresponds to the example of FIG. FIG. 25 restricts the value of G to a power of 2, and corresponds to FIG.

  Further, as described with reference to FIG. 14, it is possible to set G to a value that is somewhat smaller than the upper limit value represented by Expression (2). In this case, the effect of increasing the degree of freedom in scheduling can be achieved. can get.

(Method of setting G for each system bandwidth range (based on the minimum value))
Another example in which G is associated with W and M will be described with reference to FIGS. 26, 27, and 28. In the examples of FIGS. 23, 24, and 25, the association of G when six types of W values are defined is shown. When a large number of Ws are set in this way, the size of the table for associating G from W and M becomes large. In order to reduce the size of the table, it is effective to use the range of W instead of using the value of W itself.

  In FIG. 26, FIG. 27 and FIG. 28, the size of the table is reduced by dividing the range of W into four: W = 16 to 10, W = 11 to 26, W = 27 to 64, and W = 65 to 100. is doing. When W is indicated as a range in this way, for example, the minimum value in the range may be substituted as a representative value of W into Equation (2) to obtain the upper limit of G. For example, when W has a range of 6 to 10 in FIG. 26, the upper limit of G may be obtained based on Expression (2) with W = 6 as a representative value. In this way, even if W takes any value in the range, it is possible to avoid a state where the number that can be assigned by the assignment method is limited.

  More specifically, FIG. 26 shows an example in which the maximum natural number (not including 0) that can be set based on the formula (2) is used as the G value using the minimum value in the W range. This corresponds to 11 examples. FIG. 27 shows an example in which the threshold value TH is set to 25 and an upper limit is applied, and corresponds to the example of FIG. FIG. 28 restricts the value of G to a power of 2, and corresponds to FIG.

  Further, even when W is shown as a range in this way, it is also possible to set G to a value somewhat smaller than the upper limit value shown in Expression (2) as described with reference to FIG. In this case, the effect of increasing the degree of freedom of scheduling can be obtained.

(Method of setting G for each system bandwidth range ((typical value within range))
Another example in which G is associated with W and M will be described with reference to FIGS. 29, 30, and 31. In the examples of FIGS. 26, 27, and 28, the table size is reduced by using the range of W when G is associated with W and M. Moreover, the upper limit of G was set based on Formula (2) using the minimum value of the range of W.

  However, as described above, in 3GPP-LTE, there are six values of W which are mainly used: 6, 15, 25, 50, 75 and 100. Therefore, if it is assumed that other than these six values are not used as W, it is not always necessary to use the minimum value of the range, and the minimum value of the values used mainly among the values included in the range may be used. .

  For example, between the W ranges 11-26, there are 15 and 25 values of W that are mainly used. Therefore, the typical value in this range is set to 15, and the upper limit may be set based on Equation (2) using this typical value. In this way, when only the value of W that is mainly used is actually used, it is possible to avoid a situation where the number that can be assigned by the assignment method is limited.

  More specifically, FIG. 29 shows an example in which the maximum natural number (not including 0) that can be set based on Equation (2) is used as the value of G using typical values in the range of W. This corresponds to 11 examples. FIG. 30 shows an example in which the threshold value TH is set to 25 and an upper limit is applied, and corresponds to the example of FIG. FIG. 31 restricts the value of G to a power of 2 and corresponds to the example of FIG.

  Even in the case where the typical value is used in this way, as described with reference to FIG. 14, it is possible to set G to a value somewhat smaller than the upper limit value represented by the equation (2). In this case, the effect of increasing the degree of freedom of scheduling can be obtained.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The figure which shows the radio | wireless transmitter which concerns on 1st Embodiment. The figure which shows the radio | wireless receiver which concerns on 1st Embodiment. The figure which shows the example of allocation of the resource block with respect to a transmission signal The figure which shows the example of allocation of the resource block with respect to a transmission signal The figure which shows the example of allocation of the resource block with respect to a transmission signal The figure which shows the example of allocation of the resource block with respect to a transmission signal The figure which shows the example of allocation of the resource block with respect to a transmission signal The figure which shows the example of allocation of the resource block with respect to a transmission signal Diagram showing an example of resource block allocation Diagram showing an example of resource block allocation The figure which shows the example of the table for setting G from W and M The figure which shows the example of allocation of the resource block with respect to a transmission signal The figure which shows the example of allocation of the resource block with respect to a transmission signal The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M A block diagram showing a radio transmitter concerning a 2nd embodiment. A block diagram showing a radio receiver concerning a 2nd embodiment. The figure which shows the example of allocation of the resource block also including the time-axis with respect to a transmission signal The figure which shows the example of allocation of the resource block also including the time-axis with respect to a transmission signal The figure which shows the example of allocation of the resource block also including the time-axis with respect to a transmission signal Diagram showing an example of control signal allocation The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M The figure which shows the example of the table for setting G from W and M

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Transmission signal generation part 12 ... System bandwidth setting part 13 ... Maximum communication bandwidth ratio setting part 14 ... Distance setting part 15 ... Assignment control part 16 ... Control signal generation part DESCRIPTION OF SYMBOLS 17 ... Signal allocation part 18 ... RF transmission part 19 ... Transmission antenna 21 ... Reception antenna 22 ... RF reception part 23 ... Signal selection part 24 ... Distance setting part 25 ... Received signal demodulator 26 ... system bandwidth information acquisition unit 27 ... maximum communication bandwidth ratio information acquisition unit 28 ... control signal demodulation units 101 to 107, 201 to 203, 301 to 302, 401, 501 ˜512, 601 to 606, 701 to 704, 801 to 803... Resource block pair 1000... Control signal 1101 to 1104, 1301 to 1304, 1307. 1201-1202, 1305-1306 ... resource block pairs

Claims (15)

In a wireless transmitter used in a wireless communication system,
A transmission signal generator for generating a transmission signal;
An assigning unit for assigning transmission signals to two resource blocks separated by a distance G on the frequency axis;
A natural number smaller than W × (1-1 / (2M)) + 1, where W is the total number of resource blocks of the wireless communication system and 1 / M is the ratio of the maximum number of resource blocks used for the allocation to W. A setting unit that sets G as 0),
And a transmitter that transmits an RF signal including the two resource blocks. In a wireless transmitter used in a wireless communication system,
A transmission signal generator for generating a transmission signal;
An assigning unit that assigns transmission signals to two resource blocks that are separated by a distance G on the frequency axis and have different positions on the time axis;
A natural number smaller than W × (1-1 / (2M)) + 1, where W is the total number of resource blocks of the wireless communication system and 1 / M is the ratio of the maximum number of resource blocks used for the allocation to W. A setting unit that sets G as 0),
And a transmitter that transmits an RF signal including the two resource blocks.   The said setting part sets the said G to the largest natural number (it does not contain 0) less than Wx (1-1 / (2M)) + 1, Either of Claim 1 or 2 characterized by the above-mentioned. The described wireless transmitter.   3. The setting unit according to claim 1, wherein the setting unit sets the G to a maximum natural number (not including 0) that is equal to or less than a threshold value and less than W × (1-1 / (2M)) + 1. The wireless transmitter according to claim 1.   The setting unit sets G1 ≦ G2 if W1 = W2 and M1 <M2 in G = G1 determined by W = W1 and M = M1, and G = G2 determined by W = W2 and M = M2. The wireless transmitter according to claim 1, wherein the G is set in the wireless transmitter.   The setting unit sets G1 <G2 if W1 = W2 and M1 <M2 in G = G1 determined by W = W1 and M = M1 and G = G2 determined by W = W2 and M = M2. The wireless transmitter according to claim 1, wherein the G is set in the wireless transmitter.   3. The radio transmitter according to claim 1, wherein the setting unit sets a power of 2 as the G. 4.   The transmission unit further includes a control signal generation unit that generates a control signal including first information indicating that the allocation is used in the allocation unit and second information indicating one of the two resource blocks. The radio transmitter according to claim 1, further comprising transmitting the control signal.   Control including first information indicating whether or not the allocation is used by the allocation unit, and second information indicating a resource block to which the transmission signal is allocated earlier in time among the two resource blocks. The radio transmitter according to claim 2, further comprising a control signal generation unit that generates a signal, wherein the transmission unit further transmits the control signal.   The first information indicating whether or not the allocation is used by the allocation unit, the second information indicating one of the two resource blocks, and the transmission signal to the resource block indicated by the second information in time 3. A control signal generation unit for generating a control signal including third information indicating whether to allocate first or later in advance, and the transmission unit further transmits the control signal. The wireless transmitter described in 1.   First information indicating whether or not the allocation is used by the allocation unit; and second information including a first index indicating a resource block to which the transmission signal is allocated temporally first among the two resource blocks; Fourth information indicating which of the resource block indicated by the second index obtained by adding the distance to the first index and the resource block indicated by the third index obtained by subtracting the distance from the first index is assigned to the transmission signal The wireless transmitter according to claim 2, further comprising: a control signal generation unit that generates a control signal including: the transmission unit further transmits the control signal. A radio receiver used in the radio communication system for receiving an RF signal transmitted from the radio transmitter according to claim 1,
A receiver that receives the RF signal and obtains a received signal;
A selector that selects the two resource blocks from the received signal;
A radio receiver comprising: a demodulator that demodulates the two resource blocks and reproduces a transmission signal. A radio receiver used in the radio communication system for receiving an RF signal transmitted from the radio transmitter according to any one of claims 8 and 9.
A receiving unit that receives the RF signal and obtains a received signal;
A selector that selects the two resource blocks from the received signal according to the second information and the G when the first information is notified;
A radio receiver comprising: a demodulator that demodulates the two resource blocks. A radio receiver used in the radio communication system for receiving an RF signal transmitted from the radio transmitter according to claim 10,
A receiver that receives the RF signal and obtains a received signal;
A selector that selects the two resource blocks from the received signal according to the second information, the third information, and the G when the first information is notified;
A radio receiver comprising: a demodulator that demodulates the two resource blocks. A radio receiver used in the radio communication system for receiving an RF signal transmitted from the radio transmitter according to claim 11,
A receiver that receives the RF signal and obtains a received signal;
A selector that selects the two resource blocks from the received signal according to the second information, the fourth information, and the G when the first information is notified;
A radio receiver comprising: a demodulator that demodulates the two resource blocks.

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