KR20080065518A - Method for frequency hopping in single carrier frequency division multiple access system - Google Patents

Abstract

A method and an apparatus for hopping the frequency in a single carrier frequency division multiple access system are provided to prevent the overlap of the mirroring performing manner from generating when performing the mirroring at each cell. A mirroring process is performed irrespective of the HARQ(Hybrid Automatic Retransmitting reQuest). When the cell A and cell B exist and an intra-sub frame hopping is supported, the hopping period is each slot unit. In the cell A, the mirroring process is performed at each hopping point by a pattern of 'on, on, on, off, on, off'. In the cell B, the mirroring process is performed by a pattern of 'on, off, on, on, off'. When in the cell A, an RU(Resource Unit)(504) is allocated to a terminal A, since the terminal has the on mirroring at the next hopping point of (k+1), the terminal performs the mirroring and uses the RU(505). Since the terminal also has the on mirroring at the next hopping point of (k+2), the terminal performs the mirroring. Since the terminal has the off mirroring at the next hopping point of (k+3), the terminal transmits the data by means of the same RU as the RU used at the previous hopping point.

Description

Frequency hopping method and apparatus in single carrier frequency division multiple access system {METHOD FOR FREQUENCY HOPPING IN SINGLE CARRIER FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM}

1 is a view for explaining the transmission characteristics of a single carrier in the prior art

2 is a diagram for explaining general frequency hopping

3 is a diagram for explaining general frequency hopping

4 is a diagram for explaining mirroring.

5A and 5B illustrate a method according to a first embodiment of the present invention.

6 is a procedure for determining an RU of a terminal or a base station for implementing the first embodiment of the present invention.

7 is an apparatus diagram of a terminal for implementing the first embodiment of the present invention.

8 is an apparatus diagram of a base station for implementing the first embodiment of the present invention.

9 is a channel structure diagram for implementing a second embodiment of the present invention.

10A to 10D are diagrams for explaining the method of the second embodiment of the present invention.

11 is a procedure for determining an RU of a terminal or a base station for implementing the second embodiment of the present invention.

12 is a channel structure diagram for implementing a third embodiment of the present invention.

13 is a diagram illustrating a method of performing mirroring regardless of HARQ according to a third embodiment of the present invention.

14 is a diagram illustrating a method of performing mirroring for each HARQ processor according to a third embodiment of the present invention.

The present invention efficiently controls a packet data channel and a control channel in the same transmission interval in a wireless communication system using a single carrier frequency division multiple access (SC-FDMA) method. A method and apparatus for adjusting channel transmission resources.

1 illustrates a transmitter structure of a localized FDMA (LFDMA) system among SC-FDMA systems.

Although FIG. 1 illustrates a method using a Discrete Fourier Transform (hereinafter referred to as DFT) and an Inverse Fast Fourier Transform (hereinafter referred to as IFFT), other transmitter implementation methods are possible.

The implementation using DFT and IFFT as shown in FIG. 1 has the advantage of facilitating change of LFDMA system parameters with low hardware complexity. Looking at the difference between OFDM and SC-FDMA in terms of transmitter structure, the LFDMA transmitter is not only an IFFT 102 used for multi-carrier transmission in an OFDM transmitter, but also a DFT precoder 101 is placed in front of the IFFT 102. Is added to In FIG. 1, the transmission modulation symbol 103 is input to the DFT 101 in units of blocks. When the DFT 101 output is mapped to the IFFT 102 input, it is sent occupying a band of adjacent subcarriers. Mapper 104 serves to map to the frequency band actually used.

2 is a diagram illustrating an example in which a terminal transmits data through any allocated resource in a typical SC-FDMA system.

In FIG. 2, one resource unit (hereinafter referred to as a RU) indicated by reference numeral 201 is configured by one or a plurality of subcarriers in the frequency domain and consists of one or several SC-FDMA symbols in the time domain. do. In FIG. 2, the part indicated by hatching is a case where two RUs are allocated for the terminal 1 to transmit data, and the part indicated by a dot is a case where three RUs are allocated for the terminal 2 to transmit data.

Referring to FIG. 2, the RUs used by the terminal 1 and the terminal 2 to transmit data continuously use a predetermined frequency band without changing in time. The resource allocation scheme or data transmission scheme is widely used when a user wants to maximize system performance through limited system resources by allocating resources by selecting a frequency domain having a good channel state. For example, in FIG. 2, the radio channel characteristic of the terminal 1 is relatively good in the frequency domain, indicated by hatching, compared to other frequency domains, while the radio channel characteristic of the terminal 2 is different in the frequency domain. This is a relatively good case compared to the frequency domain. A method of selectively allocating resources by selecting a frequency domain having a good channel response in the frequency domain as described above is commonly referred to as frequency selective resource allocation or frequency selective scheduling. In the above description, data transmission from the terminal to the base station is exemplified for ease of explanation, but the same may be applied to the data transmission from the downlink, ie, the base station to the terminal. That is, in the case of the downlink, RUs indicated by hatching and dots in FIG. 2 indicate resources used when the base station transmits data to the terminal 1 and resources used when the base station transmits data to the terminal 2.

The frequency selective scheduling is not always easy. For example, in the case of a terminal moving at a high speed, the frequency selective scheduling is not easy because the channel state changes rapidly. This is because the base station scheduler selects a frequency region having a relatively good channel state to a specific terminal and allocates resources to the terminal, and the terminal receives resource allocation information from the base station and actually attempts to transmit data through the allocated resources. Since the channel environment has already changed a lot, it is not possible to guarantee that the selected band is in a relatively good channel state for the terminal.

Even if a small amount of frequency resources are continuously required, such as a Voice over Internet Protocol (VoIP) service, the signaling overhead may be large when the terminal reports the channel state for frequency selective scheduling. As such, there is a frequency hopping method that may be used when frequency selective scheduling is not easy.

3 is a diagram illustrating an example in which a frequency hopping scheme is used in a conventional FDMA system.

Referring to FIG. 3, it can be seen that a frequency resource used for transmitting data by one UE is continuously changing in time. The frequency hopping process as described above has an effect of randomizing channel quality and interference during data transmission. In other words, because different frequency positions are transmitted at each time point, different channel characteristics are used, and since the frequency used is different each time, neighboring cells receive interference signals from different terminals each time, and thus the amount of interference varies at each transmission time. (diversity) effect can be obtained.

However, in the SC-FDMA system, it is difficult to perform frequency hopping with a specific pattern independently of the location of the RU used as shown in FIG. 3. For example, in FIG. 3, when the RUs of 301 and 302 are allocated to different terminals, there is no problem. However, when the RUs of 301 and 302 are allocated to one UE, the hopping is performed at positions 303 and 304 after frequency hopping is applied at the next transmission time. It is not a continuous RU. Therefore, the UE cannot transmit two RUs.

Therefore, in order to obtain frequency diversity in SC-FDMA system, a mirroring method rather than a frequency hopping method is proposed and discussed.

4 is a view for explaining a mirroring method.

The mirroring method discussed in the related art is a method of symmetrically moving the RU with respect to the center frequency in the frequency band for transmitting the entire data. For example, the RU located at 401 moves to position 403 at the next transmission time point, and the RU located at 402 moves to position 404 at the next transmission time point. Using the mirroring method as described above has a merit that frequency hopping can be performed while satisfying a single carrier property since successive RUs move without falling.

However, this method has a disadvantage in that the pattern is fixed as one because there is no way to move the RU other than the mirroring method of changing the position of the RU based on the center frequency. Thus, when this method is applied, frequency diversity can be obtained to some extent, but it is difficult to randomize interference. In detail, if mirroring is applied again after moving to the opposite RU, it moves to the original RU position, so there is only one applicable RU movement pattern. So if you have multiple cells, you can't have different patterns for each cell. If the RU 401 indicated by a dot in Cell A is assigned to one terminal for a certain time and the RU 405 indicated by an outer line hatched in Cell B is assigned to another terminal, in the mirroring method, since the moving pattern is one, the dot is continuously The terminal using the RU denoted by is received interference from the terminal using the RU indicated by the outer line hatched. In this case, when the terminal of Cell B is placed near the Cell A and causes a large interference, the terminal using the RU indicated by the point of the Cell A has a poor reception quality.

An object of the present invention is to provide a method for randomizing interference between adjacent cells when a mirroring method is used to obtain frequency diversity.

To this end, the present invention determines whether mirroring is applied at every hopping time point, and proposes a method and a transmitting / receiving apparatus for determining this with a different pattern for each cell.

In the present invention, when frequency hopping is supported to increase the frequency diversity effect, whether or not frequency hopping is supported and whether mirroring is applied is applied differently at every hopping time point, and a method of determining this with a different pattern for each cell and We propose a transceiver.

According to an embodiment of the present invention, in a frequency hopping method in a single carrier frequency division multiple access communication system, generating a plurality of sequences for determining whether to perform mirroring, allocating the sequences for each cell, Determining whether to perform mirroring for a resource unit according to the sequence value allocated to each cell at each hopping time point, and transmitting data using the resource unit at a position determined according to a result of mirroring according to the determination. Characterized in that it comprises a.

In addition, according to an embodiment of the present invention, in a frequency hopping method in a single carrier frequency division multiple access communication system, frequency hopping bands which are sets of resource units allocated to obtain frequency diversity of an entire frequency resource, and frequency Dividing into frequency scheduling bands, which are sets of resource units allocated through selective scheduling, generating a plurality of sequences for determining whether to hop between the frequency hopping bands and performing mirroring; Determining whether to perform hopping between the frequency hopping bands for the resource unit and whether to perform the mirroring according to the sequence value allocated to each cell at every hopping time point; and between the frequency hopping bands according to the determination. The result of hopping or mirroring Using the resource unit of La determined position characterized in that it comprises the step of transmitting data.

In addition, according to an embodiment of the present invention, in the transmitting apparatus for performing frequency hopping in a single carrier frequency division multiple access communication system, a sequence generator for generating a plurality of sequences for determining whether to perform mirroring, every hopping A data transmission controller determining whether to perform resource mirroring for each cell according to the sequence value generated by the sequence generator at each time point, and determining a location of a resource unit to be used by performing mirroring according to the determination; and determined according to base station scheduling. And a mapper which maps and transmits a positive data symbol to a resource unit determined by the data transmission controller.

In addition, according to an embodiment of the present invention, in a receiving apparatus for performing frequency hopping in a single carrier frequency division multiple access communication system, a sequence generator for generating a plurality of sequences for determining whether to perform mirroring, every hopping A scheduler for determining whether to mirror resource units for each cell according to the sequence value generated by the sequence generator at each time point, and performing mirroring according to the determination to determine the location of resource units to be used for each terminal, and the received data. The demapper may be classified for each terminal according to the resource unit determined by the scheduler, and the decoder may be configured to decode the signal classified for each terminal into data symbols.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

In the present invention, in order to obtain frequency diversity while satisfying a single carrier characteristic in an uplink SC-FDMA system, inter-cell interference randomization is performed when data is transmitted using different RUs at every specific time point by a general frequency hopping or mirroring method. It provides a method for increasing.

First, for ease of explanation, the data channel is defined as follows.

FS band (Frequency scheduling band): A set of RUs allocated through frequency selective scheduling, which may consist of a contiguous RU or a set of distributed RUs.

FH band (frequency hopping band): A set of RUs that transmit to obtain frequency diversity rather than frequency selective scheduling, which may consist of a contiguous RU or a set of distributed RUs. The FH band may consist of one or more sub-FH bands.

Mirroring: A method in which RUs located on both sides of a sub-carrier or a central RU in a sub-FH band are symmetrically moved.

Hopping time point: A time point for moving a location by hopping or performing mirroring. Depending on how hopping or mirroring is applied, it has the following period.

In case of supporting intra-subframe hopping & inter-subframe hopping: slot unit level

In case of supporting only inter subframe hopping: one sub-frame level

<First Embodiment>

In the first embodiment of the present invention, a method for enabling mirroring between cells to be turned on or off and determining the cell according to a different pattern for each cell is proposed. By using different patterns as much as possible between cells and reducing the probability of applying mirroring, the effect of randomizing the interference between cells can be maximized.

FIG. 5 illustrates a method according to a first embodiment of the present invention. FIG. 5A illustrates a method of performing mirroring irrespective of a hybrid automatic retransmission request (HARQ), and FIG. 5B independently of each HARQ processor. It shows how to perform mirroring.

Referring to FIG. 5A, since it is assumed that Cell A and Cell B exist and support intra-sub frame hopping, the hopping period is in units of slots. In Cell A, on, on, on, off, on, off,… at each hopping point. Mirroring is applied in the pattern of, and in Cell B it is determined whether to apply the mirroring in the on, off, on, on, off pattern. For example, if RU 504 is assigned to UE A in Cell A, this UE performs mirroring and uses RU 505 because mirroring is turned on at (k + 1), the next hopping point, and then hopping. Mirroring is also performed at the point of time (k + 2), so mirroring is performed. Since mirroring is off at the next hopping point (k + 3), data is transmitted using the same RU as Ru used at the previous hopping point.

As described above, since mirroring is turned on and off for each cell at each hopping time, the same RU may be used at a specific time, but the probability of using the same RU again at the next hopping time is low. For example, referring to the case in which Cell A 501 allocates RU 504 to one terminal for a certain period and Cell B 502 assigns the same RU 508 to another terminal, When the UE is located close to the Cell A 501, the UE of the Cell A 501 may receive a large amount of interference from the UE of the Cell B 502 at the k-th hopping point. However, at the next (k + 1) th hopping time point, Cell A 501 performs mirroring, so it transmits data using RU 505 and Cell B 502 does not apply mirroring and uses the same RU 509. Since the data is transmitted, the terminal of Cell A 501 and the terminal of Cell B 502 use different RUs.

In FIG. 5B, mirroring is applied differently for each cell in the same manner as in FIG. 5A. In FIG. 5B, when the mirroring is applied, the RU used at the immediately previous hopping point is not the reference, but the RU belonging to the same HARQ process. Becomes That is, the UE located in Cell A 513 performs mirroring because mirroring is turned on at the k-th hopping time point, not mirroring based on the RU information used at the (k-1) -th time immediately before the hopping time point (k). It is to use the mirrored RU 518 for the RU 517 used in the -RTT + 1) th. The round trip time (RTT) means a time taken to send an initial transmission when a response received after transmitting data is NACK and a response to retransmission is an ACK. In other words, the data transmitted using the RUs 518 and 519 are retransmission data of the data transmitted using the RUs 516 and 517 or data of the same HARQ process. When mirroring is performed in consideration of HARQ RTT as described above, it is convenient to define a mirroring pattern to use different RUs as much as possible during initial transmission and retransmission. However, the complexity of managing the mirroring pattern for each HARQ process may occur.

Next, a pattern for determining mirroring for the preferred implementation of the frequency hopping method according to the first embodiment of the present invention will be described.

First, a method of determining whether to mirror according to a value generated in a sequence at each hopping time point using a specific sequence. In the first embodiment of the present invention, since the value of the sequence is not required to indicate the position of the RU to be hopped, it is to indicate whether mirroring is performed, that is, whether it is on or off, and thus, two levels of values are generated. Use a sequence. In general, using a binary sequence, it is possible to generate one of two values, 0 or 1.

Second, in order to minimize RU collisions between neighboring cells, a plurality of sequences are generated and assigned to each cell in order to apply a different pattern between at least neighboring cells. As a possible example, an orthogonal code set such as a Walsh code may be generated and allocated one by one for each cell, and on / off may be determined according to 0 or 1 at every mirroring time point. Alternatively, on / off may be determined according to the generated value at each transmission time by using a sequence that generates a random value such as a pseudo noise sequence having a different seed value for each cell (hereinafter, referred to as a PN sequence). It may be. Compared to the former method, the method using the PN sequence has a greater degree of randomization between arbitrary cells, thereby minimizing the same movement of the RUs. In the following description, a method using a PN sequence is described.

In order to generate the PN sequence value, a specific seed is required for each cell, and common timing information must be input to obtain the same PN sequence value between terminals in the same cell. As the timing information, a time difference from an absolute time to a current time may be used, or a common time frame counting value such as a system frame number (SFN) may be used.

6 shows the operation procedure of the terminal for determining mirroring for the preferred implementation of the first embodiment of the present invention. The base station also performs the same procedure to receive data of the terminal.

Referring to FIG. 6, when a UE receives a schedule of a specific RU from the BS, the UE first generates a PN sequence value in step 601. Next, in step 602, the generated PN sequence value is examined. If the generated PN sequence value is 0, the process proceeds to step 604. Since mirroring is turned off, the previously used RU is used. If the generated PN sequence value is 1, the process proceeds to step 603. Since mirroring is turned on, a new RU is used by applying mirroring. Mirroring moves the two RUs symmetrically from each other in the center of the entire FH band, so that the newly mirrored RU can be found based on the information of the RU used when transmitting data. The method can be expressed by the following equation.

H (r) = N _FH -r

In Equation 1, r denotes an RU which is a reference for mirroring, and in FIG. 5A, always means a RU used at a previous hopping point, and in FIG. 5B, RU used at a previous hopping point in the same HARQ process. do. H (r) means RU to be used after being mirrored. N _FH means the number of RUs belonging to the FH band.

7 illustrates a terminal device for a preferred implementation of the first embodiment of the present invention.

Referring to FIG. 7, the data symbol generator 703 generates data. In this case, the amount of data that can be transmitted for each TTI is determined by base station scheduling. The data symbols generated by the data symbol generator 703 are converted into signals in the frequency domain through the FFT apparatus 705 for SC-FDMA transmission. In this case, the size of the FFT apparatus 705 is equal to the number of data symbols generated by the data symbol generator 703. The output signal of the FFT apparatus 705 is mapped to the frequency resource actually assigned to the corresponding terminal in the mapper 706. At this time, the information of the allocated frequency resource is determined by receiving RU information to be transmitted from the data transmission controller 702. The data transmission controller 702 finds the RU information to be actually used for data transmission based on the scheduled RU information and mirroring. Whether or not mirroring has a different pattern according to the PN sequence value for each cell requires the PN sequence generator 701 for this purpose. The method of determining the RU to use from the output value of the PN sequence generator 701 follows the method described above. The output signal of the mapper 706 is converted into a signal in the time domain by the IFFT apparatus 707 and transmitted.

8 shows a base station apparatus for a preferred implementation of the first embodiment of the present invention.

Referring to FIG. 8, the received signal is converted into a signal in the frequency domain in the FFT apparatus 806. The output signal of the FFT device 806 is input to the demapper 805 and separated into signals received for each terminal. When the demapper 805 performs the above operation, UE-specific RU allocation information determined by the uplink scheduler 802 is used. The uplink scheduler 802 generates RU information for each terminal by using the scheduled RU information and whether to mirror. Whether or not mirroring has a different pattern according to the PN sequence value for each cell requires the PN sequence generator 801 for this purpose. The method of determining the RU to use from the output value of the PN sequence generator 801 follows the method described above. The received signal divided by the demapper 805 is input to the IDFT apparatus 804 for each terminal. The IDFT device 804 receives a received signal corresponding to UE1 (UE1) from the demapper 805 as an input, converts it into a time domain, and then converts it into a serial signal in the P / S device. The data symbol decoder 803 demodulates the transmission data.

Second Embodiment

In the second embodiment of the present invention, whether to hop between sub-FH bands and mirroring on / off are combined, and one of the combinations is arbitrarily selected to determine the location of the transmitting RU. At this time, each cell has a different pattern and selects a combination.

That is, the second embodiment of the present invention divides the entire frequency resource into FH bands and FS bands, and proposes a channel structure for sufficiently obtaining frequency hopping gain in the FH band and sufficiently obtaining frequency bands that can be allocated in the FS band. .

9 shows a channel structure according to a second embodiment of the present invention.

Referring to FIG. 9, sub FH bands are defined at both ends of the entire frequency band as shown in 901 and 903, and the center frequency band is used as the FS band as shown in 902. In this case, the UEs using the FH band can hop to the sub FH bands at both ends, thereby sufficiently obtaining the frequency hopping gain. In the case of the FS, since a continuous frequency must be allocated due to the characteristics of the SC-FDMA, according to the second embodiment of the present invention, the frequencies in the FS band are configured not to be dropped by the FH band so as to maximize the continuous frequency allocation. Can increase.

Next, in the channel structure proposed in the second embodiment of the present invention, a frequency diversity gain is sufficiently obtained, and hopping between sub-FH bands is performed to allow variable RU allocation in consideration of a single carrier characteristic, and mirroring is performed in the sub-FH band. The method will be described. In addition, in order to maximize the interference randomization gain between adjacent cells as in the first embodiment of the present invention, hopping on / off and mirroring on / off are applied between sub-FH bands with different patterns for each hopping point for each cell. .

As shown in Table 1, four combinations are possible depending on whether hopping between sub-FH bands and mirroring are performed. At each hopping time point, one of these combinations is selected and applied with a different pattern for each cell.

Combination FH band Mirroring One on on 2 off off 3 off on 4 on off

10A and 10B are views for explaining a second embodiment of the present invention.

First, referring to FIGS. 10A and 10B, a case in which Cell A 1001 and Cell B 1007 exist is illustrated. Herein, since it is assumed that intra TTI hopping is supported, the hopping time becomes 1 slot. For Cell A (1001), a combination of 3-> 1-> 4-> 3-> 2-> 1-> 2-> 3 was selected, and for Cell B (1007), 3-> 4-> The combination of 2-> 1-> 3-> 2-> 1-> 4 order was chosen.

That is, in the Cell A 1001, the RU 1002 is determined at the k-th hopping time, but since the combination 1 is selected at the (k + 1) -th hopping time, the RU 1005 is performed by performing both sub-FH band hopping and mirroring. Is determined. Since the combination 4 is selected at the next hopping time point k + 2, the RU 1003 is determined because hopping between sub-FH bands is performed but mirroring is not applied.

Referring to the case of using different combinations between cells through Cell B 1007, Cell B 1007 uses the same RU 1008 as Cell A 1001 at the k-th hopping point. However, in the next (k + 1) th hopping time, Cell A (1001) hops between sub FH bands and performs mirroring, but in case of Cell B (1007), only hopping between sub FH bands is performed without mirroring. Therefore, RU 1009 different from Cell A 1001 is used. Of course, other terminals of Cell B 1007 may use the same RU as RU 1005, but it is better to receive interference randomization gains from different terminals at each time point than to continue to collide with the same terminals. Can be.

10C and 10D, when applying the hopping and mirroring between the sub-FH bands as described above, the next RU to be used is not determined based on the position of the RU used at the previous hopping point, but is applied differently for each HARQ process.

That is, when determining the location of the RU 1013, the sub-FH band hopping is not performed based on the RU information used at the (k-1) -th hopping time point, but the RU (s) previously used for data transmission within the same HARQ process ( Hopping between sub-FH bands is performed based on 1014).

Next, as a pattern for selecting a combination of hopping or mirroring between sub-FH bands for a preferred implementation of the second embodiment of the present invention, selecting a combination according to a value generated in a sequence at each hopping time point using a specific sequence. The method will be described.

First, since the sequence value is not to determine the position of the RU to be hopped, but to determine only four combinations of hopping on / off and mirroring on / off between sub-FH bands, a sequence that generates four levels of values is used. . In general, four combinations can be generated by using four-level (quaternary) sequences or by creating and combining two binary sequences. In this case, the sequence generation method may use a general sequence generation method, and thus a detailed description thereof will be omitted.

Second, in order to apply a different pattern between at least neighboring cells in order to minimize RU collisions between the neighboring cells, a plurality of sequences are generated and allocated to each cell. As a possible example, an orthogonal code set such as Walsh may be generated and assigned to each cell, and a combination may be selected by generating a value at each hopping time point. Alternatively, the combination may be determined according to a sequence value generated at each transmission point by using a sequence that generates a random value such as a pseudo noise sequence having a different seed value for each cell. This method can minimize the random movement of the same RU again from the previous hopping time point because the PN sequence randomness between the cells is greater than the former method. In the following description, a method using a PN sequence is described.

In order to generate the PN sequence value, absolute timing information for obtaining the same PN sequence value between the specific seed and the terminals in the same cell for each cell is required. As the timing information, a time difference from an absolute time to a current time may be used, or a common time frame parameter used in a cell such as SFN may be used.

11 illustrates an operation procedure of a terminal for a preferred implementation of the second embodiment of the present invention. The base station also performs the same procedure to receive data of the terminal.

Referring to FIG. 11, when a specific RU is scheduled from a base station, a PN sequence value is generated in step 1101, and the process proceeds to step 1102 to check whether the generated sequence value is 1,2,3,4. If 1, the process proceeds to step 1103 to select a combination of mirroring on and sub-FH band hopping on. If 2, the process proceeds to step 1104 to select a combination of mirroring off and hopping off between sub-FH bands. If 3, the process proceeds to step 1105 to select a combination of mirroring off and sub-FH band hopping on. Finally, if 4, go to step 1106 to select a combination of mirroring on and sub-FH band hopping off. In step 1107, the location of the RU to be transmitted is determined according to the selected combination, and in step 1108, data is transmitted using the determined RU.

Since the transceiver device for a preferred embodiment of the second embodiment of the present invention is the same as the transceiver device according to the first embodiment of the present invention, description thereof will be omitted. However, in the second embodiment of the present invention, not binary values of 0 or 1 are generated like the PN sequence generators 701 and 802 according to the first embodiment of the present invention, but one of four values of 1 to 4 is generated. To the data transmission controller 702 and the uplink scheduler 802 to determine the position of the transmittable RU.

Third Embodiment

12 shows a channel structure according to a third embodiment of the present invention.

In the third embodiment of the present invention, when there are a plurality of sub FH bands as shown in FIG. 12, mirroring can be turned on or off between cells in a system that always hopes between the sub FH bands. Then, we propose a method for determining this according to different patterns for each cell. In this case, if the probability of applying mirroring is reduced by using a different pattern between cells as much as possible, the effect of randomizing interference between adjacent cells can be maximized.

13 and 14 illustrate a method according to a third embodiment of the present invention. FIG. 13 illustrates a method of performing mirroring without regard to a hybrid automatic retransmission request (HARQ), and FIG. 14 shows HARQ processors. It shows how to perform mirroring independently.

Referring to FIG. 13, since it is assumed that Cell A 1301 and Cell B 1311 exist and support intra-sub frame hopping, the hopping period is in units of slots. In Cell A 1301, on, on, on, off, on, off,... Mirroring is applied in a pattern of &lt; RTI ID = 0.0 &gt;, &lt; / RTI &gt; Mirroring is applied in the pattern of. For example, if a specific RU 1302 is allocated to the UE at the k-th hopping time in Cell A 1301, the UE always hops to the sub-FH band at the next hopping time point (k + 1), so that the sub-FH band # Since it hops to 2 and mirroring is turned on, mirroring is performed to use the RU 1303. Also at the next hopping point (k + 2), the sub-FH band is hopped to sub-FH band # 1, and mirroring is turned on to perform mirroring to use the RU 1304. At the next hopping time point (k + 3), the sub-FH band hopping is performed, and thus, the sub-FH band # 2 is hopped, and since the mirroring is off, the RU 1305 is used.

Cell B 1311 defines a mirroring pattern differently from Cell A 1301. In other words, mirroring is turned on and off for each cell at a corresponding hopping time point. This may cause Cell A 1301 and Cell B 1311 to use the same RU at a particular hopping point, and the possibility of using the same RU again at the next hopping point occurs.

For example, referring to the case in which Cell A 1301 assigns RU 1302 to UE A for a certain period and Cell B 1311 assigns the same RU 1312 to UE B, RU 1312 is allocated. When the terminal B of the received Cell B 1311 is located close to the Cell A 1301, the terminal A of the Cell A 1301 to which the RU 1302 is allocated is the terminal of the Cell B 1311 at the k-th hopping time point. There is a possibility of a large amount of interference from B. However, at the next (k + 1) -th hopping time point, Cell A 1301 performs sub-FH band hopping and mirroring, thereby transmitting data using RU 1303, and Cell B 1311 after sub-FH band hopping. Since mirroring is not applied, data is transmitted using the RU 1313. As such, the terminal A of the cell A 501 and the terminal B of the cell B 502 may use different RUs at the (k + 1) th hopping time point, thereby preventing interference from the same terminal.

Meanwhile, in FIG. 14, mirroring is applied after performing hopping between sub-FH bands as in FIG. 13, and whether or not mirroring is applied to each cell is different. In FIG. 14, the mirroring is applied at the time of the previous transmission when mirroring is applied. The RU is not a reference, but a RU belonging to the same HARQ process. That is, the UE located in Cell A 1401 performs mirroring because mirroring is turned on at the k-th hopping time point, not mirroring based on the RU information used at the (k-1) th time point immediately before transmission (k). It is to use the mirrored RU 518 for the RU 517 used in the -RTT + 1) th. The round trip time (RTT) refers to the time taken to perform initial transmission when the response received after transmitting data is NACK and the response to retransmission is ACK. As described above, when mirroring is performed in consideration of HARQ RTT, a mirroring pattern that uses different RUs as much as possible for initial transmission and retransmission may be defined, and thus interference diversity effect may be maximized.

The operation procedure of the terminal for determining mirroring for implementing the method according to the third embodiment of the present invention is almost the same as the terminal procedure of the first embodiment of the present invention, and in the third embodiment of the present invention, determining the RU. In this case, hopping is always performed between sub FH bands.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention determines whether to apply mirroring at every hopping time point, and by determining this with a different pattern for each cell, it is possible to randomize interference between adjacent cells while increasing the frequency diversity effect.

Claims (16)

A frequency hopping method in a single carrier frequency division multiple access communication system, Generating a plurality of sequences for determining whether to perform mirroring; Allocating the sequences for each cell and determining whether to perform mirroring for a resource unit according to the sequence value allocated for each cell at each hopping time point; And transmitting data using the resource unit at the location determined according to a result of mirroring according to the determination. The method of claim 1, The resource unit which is the reference for performing the mirroring frequency hopping method, characterized in that the resource unit used at the time of the previous hopping. The method of claim 1, The resource unit which is the basis of the mirroring is a frequency hopping method, characterized in that the resource unit previously used in the same HARQ process. The method of claim 1, And when the mirroring is not performed at a specific hopping time, transmitting data using the resource unit used at the previous hopping time. The method of claim 1, The sequence is a frequency hopping method, characterized in that the orthogonal code for each cell in the orthogonal code set. The method of claim 1, And the sequence is a pseudo noise sequence having a different seed value for each cell. A frequency hopping method in a single carrier frequency division multiple access communication system, Dividing the entire frequency resource into frequency hopping bands, which are sets of resource units allocated to obtain frequency diversity, and frequency scheduling band, which is a set of resource units allocated through frequency selective scheduling; Generating a plurality of sequences for determining whether to hop between the frequency hopping bands and whether to perform mirroring; Allocating the sequences for each cell and determining whether to perform the hopping between the frequency hopping bands for a resource unit and performing the mirroring according to the sequence value allocated for each cell at each hopping time point; And transmitting data using a resource unit at a location determined according to a result of performing the hopping or mirroring between the frequency hopping bands according to the determination. The method of claim 7, wherein The resource unit which is the reference for performing the mirroring frequency hopping method, characterized in that the resource unit used at the time of the previous hopping. The method of claim 7, wherein The resource unit which is the basis of the mirroring is a frequency hopping method, characterized in that the resource unit previously used in the same HARQ process. The method of claim 7, wherein And when the mirroring is not performed at a specific hopping time, transmitting data using the resource unit used at the previous hopping time. The method of claim 7, wherein And said sequence is an orthogonal code set. The method of claim 7, wherein And the sequence is a pseudo noise sequence having a different seed value for each cell. A transmission apparatus for performing frequency hopping in a single carrier frequency division multiple access communication system, A sequence generator for generating a plurality of sequences for determining whether to perform mirroring; A data transmission controller for determining whether to perform resource mirroring for each resource unit according to the sequence value generated by the sequence generator at every hopping time point, and for determining the position of the resource unit to be used by performing mirroring according to the determination; And a mapper for mapping the amount of data symbols determined according to the base station scheduling to the resource units determined by the data transmission controller and transmitting the mapped data symbols. The method of claim 13, Frequency hopping bands, which are sets of resource units allocated to obtain frequency diversity, and frequency scheduling bands, which are sets of resource units allocated through frequency selective scheduling, The data transmitter, And assigning the sequences for each cell and determining whether to perform the hopping between the frequency hopping bands for a resource unit and performing the mirroring according to the sequence value allocated for each cell at each hopping time point, and performing the frequency hopping according to the determination. And a resource unit to be used according to hopping between bands or a result of performing the mirroring. A receiving apparatus for performing frequency hopping in a single carrier frequency division multiple access communication system, A sequence generator for generating a plurality of sequences for determining whether to perform mirroring; A scheduler for determining whether to mirror resource units for each cell according to the sequence value generated by the sequence generator at every hopping time point, and for determining the location of resource units to be used for each terminal by performing mirroring according to the determination; A demapper for classifying the received data for each terminal according to the resource unit determined by the scheduler; And a decoder which decodes a signal classified for each terminal into data symbols. The method of claim 15, Frequency hopping bands, which are sets of resource units allocated to obtain frequency diversity, and frequency scheduling bands, which are sets of resource units allocated through frequency selective scheduling, The scheduler, And assigning the sequences for each cell and determining whether to perform the hopping between the frequency hopping bands for a resource unit and performing the mirroring according to the sequence value allocated for each cell at each hopping time point, and performing the frequency hopping according to the determination. And a resource unit to be used for each terminal according to hopping between bands or a result of the mirroring.

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