KR20060101936A - Method and apparatus for transmitting control information and data symbol in ofdm system - Google Patents

Abstract

The present invention provides a method and apparatus for more effectively providing an adaptive modulation scheme and a cyclic prefix technique in an orthogonal frequency multiplexing (OFDM) mobile communication system. The present invention provides a method of transmitting data in a mobile communication system supporting multiple carriers, the method comprising: generating at least one symbol string among a data symbol sequence, a pilot symbol sequence, and a control symbol sequence for the data symbol sequence; And concatenating at least one guard period to prevent adjacent symbol interference in the generated symbol string, and transmitting a time slot comprising the guard period and the generated symbol string. The configuration of the slot is characterized by a variable. The present invention has the effect of quickly demodulating data symbols and reducing overall delay by receiving and demodulating pilot symbols and control information in advance before performing demodulation of the data symbols.

OFDM, timeslot, control symbol, data symbol, pilot symbol, unicast, multicast, guard interval

Description

METHOD AND APPARATUS FOR TRANSMITTING CONTROL INFORMATION AND DATA SYMBOL IN OFDM SYSTEM}

1 is a diagram illustrating a time frequency mapping structure for transmitting a pilot signal and a control signal in an OFDM system according to the prior art.

2 conceptually illustrates an OFDM symbol structure.

3 illustrates a variable timeslot structure in accordance with a preferred embodiment of the present invention.

4 illustrates a variable timeslot structure according to a first embodiment of the present invention.

5 illustrates a variable timeslot structure according to a second embodiment of the present invention.

6 illustrates a variable timeslot structure according to a third embodiment of the present invention.

7 illustrates a variable timeslot structure according to a fourth embodiment of the present invention.

8 illustrates a variable timeslot structure according to a fifth embodiment of the present invention.

9 is a structural diagram showing an OFDM transmitter for transmitting a timeslot according to a preferred embodiment of the present invention.

10 is a structural diagram showing an OFDM receiver for receiving a timeslot according to a preferred embodiment of the present invention.

The present invention relates to a next generation mobile communication system, and more particularly, to provide a method and apparatus for using a time slot structure that is adaptively variable according to a change in channel conditions and a service provided.

Orthogonal Frequency Division Multiplexing (OFDM) method is a method useful for high-speed data transmission in wired and wireless communication systems and transmits data using multi-carriers.

In connection with this, next-generation mobile communication systems have proposed a method of using broadband spectrum resources to support high-speed and high-quality data transmission services. In the case of using such broadband spectrum resources, fading effects on a wireless transmission path due to multipath propagation occur in a mobile communication environment. In addition, an effect of frequency selective fading also occurs within a transmission band.

In a mobile communication system using a plurality of sub-carriers such as the OFDM system, a problem arises in that a transmission symbol period is lengthened on a time axis in proportion to the number of subcarriers used. Therefore, a study on a method for reducing inter-symbol interference (hereinafter referred to as 'ISI') in a radio channel having multipath fading, and a flat channel response of each subcarrier band In order to approximate to, the researches to show the robust characteristics for the frequency selective fading have been actively conducted.

In the OFDM scheme, a multi-carrier modulation (MCM: multi-transformer) converting a serially transmitted symbol string into a parallel signal and modulating each of the symbols into a plurality of sub-carriers having mutual orthogonality. It is a kind of carrier modulation, and the multi-carrier modulation process can be implemented by an inverse fast fourier transform (IFFT). The frequency modulation process implemented by IFFT plays a role of converting a transmission symbol sequence in a frequency domain into a time domain signal, and the reverse process of the frequency modulation process can also be implemented as a Fast Fourier Transform (FFT) at a receiver. Do.

The above-described transmission symbol strings generally include all data symbols, pilot symbols, control signals, and the like. The pilot symbols are composed of predetermined symbol values known to the transceiver, and used for the purpose of channel response estimation and cell search of each subcarrier band. The control symbol is various control information used in data modulation and demodulation and signal transmission and reception, and includes, for example, power control information (TPC), transmission format and modulation method information (TFRI), and the like.

1 is a diagram illustrating a structure for transmitting data symbols, pilot symbols, and control symbols together using time frequency mapping in a conventional OFDM communication system.

Referring to FIG. 1, OFDM symbols (data symbols, pilot symbols, control symbols) are mapped to a two-dimensional plane structure representing a frequency domain on the horizontal axis and a time domain on the vertical axis.

In the time frequency unit, the letter 'D' represents the data symbol 101 and the letter 'P' represents the pilot symbol 102. Further, the letter 'S' represents the control symbol 103, respectively. Here, one column 104 of the horizontal axis, which means the frequency domain, means one subcarrier band and denotes this unit as an appropriate frequency unit f _s through which a signal transmitted in each subcarrier signal can be independently transmitted. In addition, one column 105 of the vertical axis representing the time domain means an OFDM symbol duration and is denoted as T _d .

In the two-dimensional frequency time mapping diagram of FIG. 1, the subcarrier spacing unit f _s and the OFDM symbol period T _d are predetermined values during initial system configuration.

The transmitter transmits the data symbols, the pilot symbols, and the control symbols by using a certain subcarrier unit and an OFDM symbol period. That is, as shown in the 2D frequency time mapping diagram, the symbol is transmitted on a subcarrier to OFDM time block that is previously promised. In the same time domain, the data symbols, pilot symbols, and control symbols can be regarded as parallel transmission at the same time.

In response, the receiving apparatus receives the one OFDM symbol, first separates a pilot symbol and a control symbol, and then demodulates a data symbol using the separated information. That is, the receiving device obtains control information necessary for data symbol demodulation and then demodulates the data symbol with reference to the control information.

2 is a diagram conceptually illustrating a structure of a conventional OFDM symbol.

Referring to FIG. 2, OFDM symbols T _d are transmission symbol strings including the data symbols, pilot symbols, and control symbols. In this case, the OFDM symbol T _d refers to a signal added after a guard interval (GI) after being output through an inverse transform Fourier transform device which is a frequency modulation device. That is, if the transmission symbol strings including data symbols, pilot symbols, and control symbols mean transmission symbols transmitted on each subcarrier in the frequency domain, the OFDM symbol means a signal unit transmitted in the time domain.

Here, block 201 denotes a guard interval, and block 202 denotes an effective symbol interval that is an output of the inverse transform Fourier transform apparatus. In particular, the guard period 201 serves to eliminate adjacent symbol interference (ISI) by designing longer than the maximum delay length of the multipath in the time domain. The guard interval 201 copies adjacent signal portions of the valid symbol interval 202 and uses a cyclic prefix of the valid symbol interval 202 to be transmitted, thereby using adjacent carrier interference ( It also plays a role in eliminating inter-carrier interference (ICI).

1 and 2 described above, in the prior art, a basic time unit for transmitting an OFDM symbol is fixed to the OFDM symbol period T _d of FIG. 2. The value is a value determined at the time of initial system setting and is a preset value determined not to generate ICI or ISI according to radio channel characteristics.

Therefore, the conventional OFDM symbol has a problem that is not suitable in the mobile communication system in which the channel characteristics change rapidly or the service characteristics to support the service characteristics change over time. That is, when a user's delay condition changes in a wireless environment, a problem arises in that it is not efficient.

In addition, after the data symbol, the pilot symbol, and the control symbol are transmitted together in one OFDM symbol, the pilot symbol or the control symbol is separately demodulated, and then the delay is demodulated using the demodulated information. There is a problem that continues to exist.

Accordingly, an object of the present invention, which is designed to solve the problems of the prior art operating as described above, provides a method and apparatus for separating a control symbol and a data symbol in a time domain in a mobile communication system supporting multiple carriers. Is in.

Another object of the present invention is to provide a method and apparatus for separating a control symbol, a pilot symbol, and a data symbol in a mobile communication system supporting multiple carriers and transmitting the same with different symbol periods.

Still another object of the present invention is to provide a method and apparatus for performing demodulation by multiplexing control symbols and pilot symbols in a frequency domain in a mobile communication system supporting multiple carriers and transmitting them in advance than data symbols.

Another object of the present invention is to provide a method and apparatus for transmitting data symbols having a variable symbol period in consideration of a channel state of data to be transmitted in a mobile communication system supporting multiple carriers.

Another object of the present invention is to provide a method and apparatus for transmitting at least one or more service data having different transmission time intervals in a mobile communication system supporting multiple carriers.

In order to achieve the above object, an embodiment of the present invention provides a method for transmitting data in a mobile communication system supporting multiple carriers.

Generating at least one type of symbol sequence among a data symbol sequence, a pilot symbol sequence, and a control symbol sequence for the data symbol sequence, and concatenating at least one guard interval to prevent adjacent symbol interference from the generated symbol sequence; And transmitting a time slot including the guard period and the generated symbol string, wherein the configuration format of the time slot is variable.

Another embodiment of the present invention, which was created to achieve the above object, in a method for receiving data in a mobile communication system supporting multiple carriers,

Receiving a time slot comprising a data symbol sequence, a pilot symbol sequence, at least one symbol sequence of a control symbol sequence for the data symbol sequence, and at least one guard interval for preventing adjacent symbol interference; In order to distinguish one type of symbol string, the at least one guard period is separated from the timeslot, wherein the format of the timeslot is variable.

Another embodiment of the present invention, which was created to achieve the above object, in a method for transmitting data in a mobile communication system supporting multiple carriers,

Generating a first multi-symbol sequence in which a control symbol sequence is multi-mapped in a data symbol sequence and a frequency domain, generating a predetermined pilot symbol sequence, and separating the first multi-symbol sequence and the pilot symbol sequence in a time domain Wherein the at least one guard interval for contiguous symbol interference is contiguously transmitted to the first multisymbol sequence and the pilot symbol sequence, and the length of the symbol sequence and the guard interval is It is characterized by being variable.

Another embodiment of the present invention, which was created to achieve the above object, in a method for receiving data in a mobile communication system supporting multiple carriers,

Receiving a time slot configured by concatenating at least one guard interval for preventing adjacent symbol interference to a first multi-symbol sequence and a pilot symbol sequence in which a control symbol sequence is multi-mapped in a data symbol sequence and a frequency domain; Removing the at least one guard interval from the; and splitting the first multisymbol sequence and the pilot symbol sequence in a time domain by using the timeslot from which the guard interval has been removed from the first multisymbol sequence. The control symbol string and the data symbol string are divided in a frequency domain, wherein the length of the symbol strings and the guard interval is variable.

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. Definitions of terms to be described below should be made based on the contents throughout the specification.

The present invention described below is directed to an Orthogonal Frequency Division Multiplexing (OFDM) system for transmitting data using multi-carriers in a manner useful for high-speed data transmission in a wired / wireless communication system. The main feature of the present invention is to provide a variable timeslot structure as a method for adaptively responding to channel and service characteristics in the OFDM system. In addition, the present invention transmits data symbols, pilot symbols, or control symbols separately in the time axis in the variable timeslot structure.

3 is a view showing a variable timeslot structure proposed in the preferred embodiment of the present invention.

Referring to FIG. 3, blocks 310 to 340 each represent timeslots of T _d1 to T _d4 having variable time lengths. The predetermined timeslot includes not only data symbols, pilot symbols, and control symbols but also guard intervals set to remove interference between the respective symbols. That is, the plurality of timeslots include one transmission length interval of a predetermined length. Configure. Herein, the timeslots of T _d1 to T _d4 are variably set according to data and channel environment to be transmitted.

First, blocks 321 to 327 are views showing in more detail the structure of a predetermined timeslot. For example, blocks 321 to 327 represent a general interior of the second timeslot. In this case, the length of each time interval of the blocks 321 to 327 is determined to be an arbitrary time length including 0, and the sum of the time interval lengths of the blocks is equal to the time length T _d2 of the second timeslot.

Blocks 321 to 327 may be divided into two parts, respectively, guard periods and transmission symbol periods. First, the guard intervals are 321 blocks, 323 blocks, 325 blocks, and 327 blocks having time lengths T _{d2, G1} to T _{d2, and G4} , respectively, and the signal type in the interval is not limited to a specific pattern.

That is, in the guard periods 321 to 327, interference between valid symbols is performed by using a zero padding method that transmits no signal or by using a cyclic prefix proposed in a general OFDM symbol. To prevent.

The transmission symbol period includes a pilot symbol interval of 322 blocks _, a pilot symbol interval of pilot, a 324 block time length T _d2, a control symbol interval of _cont , and a data symbol interval of 326 blocks of time length T _{d2, data} . At this time, the arrangement order of the pilot symbol section 322, the control symbol section 324, and the data symbol section 326 can be changed in any order. In addition, a signal transmission method in the transmission symbol interval including the pilot symbol interval 322, the control symbol interval 324, and the data symbol interval 326 is sequentially transmitted in the time domain and in parallel in the frequency domain. You can use either method.

In the present invention, for convenience of description, an OFDM system using a transmission scheme that is transmitted in parallel for data symbol transmission is assumed and described. However, a method of sequentially transmitting may also be used.

In addition to varying the length of each time slot of FIG. 3, the time slot includes all the variability of symbols and guard intervals in each time slot. In addition, the size of the fast Fourier transformer or the inverse fast Fourier transformer used in the parallel transmission scheme and the data type to be transmitted in the data symbol portion can also be varied. Accordingly, as described above, the OFDM parameters can be flexibly changed between timeslots, thereby making it possible to adapt well to changes in transport channels and to efficiently provide various traffic and services.

[First Embodiment]

4 shows the structure of a timeslot according to the first embodiment of the present invention.

Referring to FIG. 4, according to the first embodiment of the present invention, a time slot includes a control symbol section 420, a pilot symbol section 440, and a data symbol section 460. In other words, the control symbol sequence is transmitted according to the time domain, and then the pilot symbol sequence and the data symbol sequence are sequentially transmitted. Compared with the blocks 321 to 327 in FIG. 3, it can be seen that the length of the time interval T _{d and G3} of the third guard interval corresponding to the block 325 is set to 0, that is, it does not exist. This will be described in more detail as follows.

First, block 410 is a guard interval for a control symbol, and has a time interval length of T _{d, G1} . Block 430, block 470 it is also present in a guard interval length of each time interval T _{d, G2,} T _{d, G4.} In addition, referring to the time slot according to the first embodiment, in 420 blocks, control symbols are sequentially transmitted in a time domain unit with a time interval length of T _{d, cont} . On the other hand, in 440 blocks, the pilot symbols are transmitted in parallel in the same frequency domain with the time interval length of T _{d, pilot} . In block 460, data symbols are transmitted in parallel in the same frequency domain with a time interval length of T _{d, data} . Here, the sequential transmission is a method in which the symbols to be transmitted are sequentially transmitted in the time domain, and the parallel transmission is a method of mapping the symbols to be transmitted in the frequency domain and then converting the symbols to a time domain signal using an inverse fast Fourier transformer. The parallel transmission is similar to the method of transmitting data in the OFDM system described above. The sequential / parallel transmission method described above can be selected irrespective of the type of the transmitted symbol. In addition, the parallel transmission is particularly robust to frequency selective fading.

In other words, the transmitting end first transmits the control symbols 420 in the period of T _{d, cont in} the time slot structure as shown in FIG. 4, and transmits the pilot symbol sequence 440 in parallel in the period of T _{d, pilot} , and then the data. The symbol string 460 is transmitted in a period of T _{d, data} . The guard interval may use a cyclic prefix or a zero-padding method. Therefore, inter-carrier interference (ICI) can be prevented. In the first embodiment, the pilot symbol string 440 and the data symbol string 460 are not transmitted within the same time period. That is, there is no guard interval, pilot symbol sequence 440 is transmitted first and then data symbol sequence 460 is transmitted.

In response to this, the receiving end performs demodulation by first receiving the control symbol sequence 420 and the pilot symbol sequence 440 first, thereby demodulating the data symbol sequence 460 more quickly. This is because the control symbol string 420 includes control information necessary for demodulation of the data symbol 460. In addition, the pilot symbol sequence 440 is received to obtain a channel estimation value for channel compensation for demodulation of the data symbol sequence 460. That is, to demodulate the data symbol portion 460, demodulation of the control symbol portion 420 and channel estimation using the pilot symbol portion 440 are performed first.

When the number of pilot symbols transmitted in parallel in 440 blocks is less than the total number of subcarriers, and thus the size of the inverse fast Fourier transformer used in block 440 is smaller than the size of the inverse fast Fourier transformer used in data symbol transmission in 460 blocks, The channel response obtained from the pilot symbols is interpolated to estimate a channel of all subcarriers.

Since pilot symbols of block 440 use a value previously known to the transmitter, when the received signal demodulates the data symbol of block 460, the interference signal by the pilot symbol can be removed in advance. Therefore, even if there is no guard interval between the pilot symbols of 440 blocks and the data symbols of 460 blocks transmitted in parallel, interference between adjacent symbols can be prevented. Since data symbols of 460 blocks are also transmitted in parallel, an effective symbol interval signal of an OFDM symbol, which is an inverse fast Fourier transformer output signal, is detected.

When the control information by block 420 and the channel estimation value by block 440 are already known, the process of demodulating the data symbols of block 460 is the same as the data demodulation process at the receiving end of a general OFDM system.

As described above in the first embodiment, the transmitter transmits the control symbol string 420 to the time domain first, sets the time slot for transmitting the pilot symbol string 440 and then transmits the data symbol string 460. do. Accordingly, the receiver demodulates the transmitted data faster by demodulating the control symbol string 420 and the pilot symbol string 440 first.

Second Embodiment

The following second embodiment also uses a structure in which the control symbol sequence and the pilot symbol sequence are separated and transmitted in the time domain, and then the data symbol sequence is transmitted. Similarly, the control symbol sequence and the pilot symbol sequence are transmitted sequentially rather than at the same time.

5 is a diagram illustrating a timeslot structure according to a second embodiment of the present invention.

Referring to FIG. 5, the guard intervals for the pilot symbols 540, that is, the time interval lengths T _{d and G2} of the second guard interval are 0 and the guard intervals of 510 blocks, 550 blocks, and 570 blocks are T _d, respectively. _It exists as a time interval length of _{, G1} , T _{d, G3} , T _{d, G4} In 520 blocks, control symbols are sequentially transmitted in a time interval length of T _{d, cont} , and in 540 blocks, the time interval length of pilot symbols T _{d, pilot} is transmitted in parallel, and in 560 blocks, data symbols are T _{d, data} time intervals. The time slot structure is transmitted in parallel with the interval length.

After receiving the timeslot, the receiver determines the transmission format and modulation scheme of the data symbols 560 by demodulating control information of the control symbols of 520 blocks before demodulating the data symbols of 560 blocks in consideration of the time. Figure out. Thereafter, channel estimation is performed on the pilot symbols of 540. In this case, since there is no guard interval between the control symbols of block 520 and the pilot symbol interval of block 540, first, the control symbols of block 520 are demodulated, and then the adjacent symbols between the control symbols 520 and the pilot symbols of block 540 are separated. After removing interference effects in advance, channel estimation is performed. In the protection interval of 550 blocks, if a cyclic prefix or zero-padding method is used, this is the same as the protection interval of the 201 block shown in FIG. 2, and the 560 block shows only the data symbols in the 202 block of FIG. 2. Same as when sent.

Accordingly, since blocks 550 and 560 have the same structure as the OFDM symbol, the data symbol sequence after the guard interval 550 is removed after using the control information of the 520 blocks and the channel estimation value of the 540 blocks previously transmitted in terms of time. Demodulate 560.

As described above, the first and second embodiments propose a timeslot having control lengths, pilot information, and data information separated in a time domain, and having different variable lengths according to the type of data to be transmitted. have. That is, demodulation of data information is made easier by transmitting control information and pilot information in a time domain in advance in one time slot than data information.

Third Embodiment

In the following description, a pilot symbol sequence is transmitted in advance in the time domain and a control symbol sequence and a data symbol sequence are mapped and transmitted in the frequency domain according to the third embodiment of the present invention. That is, FIG. 6 proposes a time slot structure in which a control symbol sequence and a data symbol sequence are mapped and transmitted in the frequency domain.

Referring to FIG. 6, a pilot symbol sequence of 620 blocks uses a parallel transmission scheme with a time interval length T _{d, pilot} , and a data / control symbol sequence of 640 blocks has a time interval length T _{d, data / cont} and parallel transmission. Use the method. Blocks 610 and 630 are guard intervals having time interval lengths T _{d, G1} , T _{d, G2} , respectively. The guard periods 610 and 630 may be applied to a cyclic prefix or zero-padding method for a pilot symbol sequence of 620 blocks and a frequency mapped data / control symbol sequence of 640 blocks, respectively. Therefore, interference between adjacent symbols is prevented due to the guard periods 610 and 630.

Also, in this embodiment, the number of pilot symbols transmitted in parallel in block 620 of FIG. 6 is smaller than the total number of subcarriers, so that the size of the inverse fast Fourier transformer (ie, number of taps) used in block 620 is 640 blocks of data / control. When smaller than the size of the inverse fast Fourier transformer used in symbol string transmission, the channel response obtained by the pilot symbol string is interpolated to estimate the channels of all subcarriers.

Data symbols and control symbols are transmitted by mapping to a predetermined subcarrier position in the frequency domain in block 640. In the receiver, a channel estimation value obtained by using pilot symbols at a predetermined position in block 620 and a control symbol in block 640 are determined. The data symbols are demodulated using the control information obtained by separating and demodulating the data.

As described above, the third embodiment of the present invention shows an example in which pilot symbols are transmitted first, and control symbols and data symbols are mapped and transmitted in the frequency domain. In this case, an example in which control symbols are transmitted first and pilot symbols and data symbols are mapped and transmitted in the frequency domain may be designed in the same manner.

Compared to the conventional method of transmitting the pilot symbol sequence, the control symbol sequence, and the data symbol sequence described in FIG. 1 by two-dimensional multiplexing in both time and frequency domains, only one of the pilot symbol sequence or the control symbol sequence Since channel estimation or control information decoding can be performed in advance by sending time multiplexing first, data demodulation is easy. In addition, since multiplexing in the frequency domain between two types of symbols is applied, frequency resource management can be efficiently performed.

Fourth Example

Hereinafter, according to the fourth embodiment of the present invention, a length of a guard interval, a size of a (inverse) fast Fourier transformer (FFT size) and a transmission symbol information type for transmission of a data symbol vary according to timeslots.

7 is a diagram illustrating a structure in which different data types transmit different data symbols for each timeslot.

Referring to FIG. 7, blocks 710 and 720 show a first time slot and a second time slot set to different lengths in an arbitrary transmission time interval (TTI).

In block 712 of the first timeslot, the control symbol sequence is sequentially transmitted in the time domain. In block 714, the pilot symbol sequence and the data symbol sequence are mapped in the frequency domain and transmitted in parallel. Blocks 711 and 713 indicate guard intervals set to prevent interference between adjacent symbols. The data of block 714 to which the guard period of block 713 is added represents a data symbol string and a pilot symbol string that are transformed into an N-sized FFT. This indicates that the pilot symbol string and the data symbol string are mapped to each other and transmitted as one OFDM symbol in the time-frequency domain.

The second timeslot has a structure in which the signal interval length of the control information is zero, that is, the control information is not transmitted. Since the control information does not change every time slot, only one control information can be transmitted for several timeslots as in the present embodiment.

The multicast data of 722 blocks to which the guard period of 721 blocks is added in the second timeslot represents a data symbol string and a pilot symbol string which are transformed into an M-size FFT. That is, the pilot symbol sequence and the data symbol sequence multiplexed in parallel in the frequency domain are shown.

The lengths of the guard intervals corresponding to blocks 711, 713, and 721 of FIG. 7 are T _{d, G1} , T _{d, G2} , T _{d, and G3} , respectively _, and the lengths of the control symbol intervals of block 712 are T _{d, cont} , The lengths of the data / pilot symbol intervals of blocks 714 and 722 are T _{d, data1} and T _{d, data2,} respectively. In this case, the sizes of the (inverse) fast Fourier transformers in blocks 714 and 722 for transmitting the data are defined as M and N, respectively. In addition, the transmission data type of 714 blocks is a unicast service method for transmitting data exclusively. On the other hand, the transmission data type of block 722 is a broadcast or multicast service scheme for transmitting data in common to a plurality of unspecified or predetermined users. Information on the data type transmitted here is already known through higher signaling.

As described above, the transmission data type is set differently for each time slot and transmitted to satisfy the quality of service. In addition, since the size of the (inverse) fast Fourier transformer for parallel transmission is also variable, it has the effect of supporting the amount of data corresponding to the service in real time.

[Example 5]

In the following fifth embodiment, a signal including variable information for each transmission time interval (TTI) is transmitted.

8 illustrates a structure for supporting a unicast service and a multicast service for each TTI. In FIG. 8, two TTIs of 810 and 850 blocks are shown, and the two TTIs each consist of N and M timeslots.

The first TTI consists of N timeslots, and the first timeslot 820 includes information related to a modulation method and a transmission format of data symbols transmitted through the N timeslots. The control symbols 822 are transmitted sequentially in the time domain. In addition, the unicast data symbols and pilot symbols are mapped in the frequency domain with a variable symbol period and transmitted in parallel.

In the fifth embodiment, it is assumed that the guard interval length, data / pilot symbol transmission interval length, and (inverse) Fourier transformer have the same size in each TTI. However, other parameters may be used within different TTIs. In FIG. 8, the guard interval length of the first TTI of block 810 is T _{d, G1} and the control symbol interval length of block 822 is T _{d, cont1} . At this time, the length of the first data / pilot symbol transmission interval is T _{d, data1} . In addition, the guard interval length of the second TTI is T _{d, G2} and the control symbol interval length of the 862 blocks is T _{d, cont2} . In this case, the length of the second data / pilot symbol transmission interval is T _{d., Data2} .

In addition, as described in the fourth embodiment, the type of data information transmitted in the data symbol of each TTI may also be changed to a unicast or broadcast / multicast type. The total length of each TTI interval and the number of timeslots per TTI may be variable. On the other hand, the structure that transmits the symbol variably based on the TTI described in the fifth embodiment has the effect of reducing the signaling overhead when considering the fact that the parameter change for each time slot is small.

Transceiver

Hereinafter, a structure for transmitting and receiving timeslots according to embodiments of the present invention will be described.

9 shows an OFDM transmitter for transmitting a timeslot according to a preferred embodiment of the present invention.

Referring to FIG. 9, an OFDM transmitter includes a symbol generator 910 for generating at least one kind of symbol strings among a data symbol sequence, a pilot symbol sequence, and a control symbol sequence for the data symbol sequence, and adjacent symbol interference with the generated symbol sequence. A guard interval inserting unit 920 for concatenating at least one guard interval to prevent the error, and a transmission unit 930 for transmitting a time slot consisting of the at least one guard interval and the generated symbol string.

Herein, as shown in the above-mentioned embodiments, the configuration format of the timeslot is variable. In more detail, the format of the timeslot may vary depending on whether or not the length of the data symbol string, the length of the pilot symbol string, and the length of the control symbol string varies. Of course, the length of the symbol strings and the guard interval may vary depending on the channel state. In this case, the configuration format for each time slot is variable within the transmission time interval, and the data type of the data symbol string is set for each time slot. That is, the data symbol sequence may have a different FFT size for each timeslot.

The transmitter 930 transmits the generated symbol strings sequentially in the time domain or in parallel in the frequency domain according to the aforementioned embodiments.

As an example, the transmitter 930 sequentially transmits the control symbol string or the pilot symbol string in the time domain, and transmits the data symbol string in parallel in the frequency domain. As another example, the transmitter 930 sequentially transmits the control symbol sequence in the time domain, and transmits the pilot symbol sequence or the data symbol sequence in parallel in the frequency domain.

As another example, the transmitter 930 may generate a first multisymbol sequence obtained by multiple mapping a control symbol sequence in a data symbol sequence and a frequency domain, and separates the first multisymbol sequence and the pilot symbol sequence in a time domain. To transmit. Here, at least one guard period for preventing adjacent symbol interference is concatenated and transmitted to the first multisymbol sequence and the pilot symbol sequence.

10 illustrates an OFDM receiver for receiving a timeslot according to a preferred embodiment of the present invention.

Referring to FIG. 10, an OFDM receiver includes at least one symbol string among a data symbol string, a pilot symbol string, and a control symbol string for the data symbol string, and at least one guard interval for preventing adjacent symbol interference. A receiver 1010 for receiving a timeslot, a guard interval separator 1020 for separating at least one guard interval from the timeslot, and the control symbol sequence or the pilot symbol sequence to obtain the data symbol sequence And a symbol string processing unit 1030 for demodulating the data symbol string after first removing the influence on the data symbol string.

Likewise, the format of the timeslot is variable. In more detail, the format of the timeslot may vary depending on whether or not the length of the data symbol string, the length of the pilot symbol string, and the length of the control symbol string varies. Of course, the length of the symbol strings and the guard interval may vary depending on the channel state. In this case, the configuration format for each time slot is variable within the transmission time interval, and the data type of the data symbol string is set for each time slot. That is, the data symbol sequence may have a different FFT size for each timeslot.

The symbol strings are received sequentially in the time domain or in parallel in the frequency domain. As an example, the control symbol sequence or the pilot symbol sequence are sequentially received in the time domain, and the data symbol sequence is received in parallel in the frequency domain. As another example, the control symbol sequence is sequentially received in the time domain, and the pilot symbol sequence or the data symbol sequence is received in parallel in the frequency domain.

As another example, the receiver 1010 may be configured by concatenating at least one guard interval to prevent adjacent symbol interference from a first multisymbol sequence and a pilot symbol sequence in which a control symbol sequence is multi-mapped in a data symbol sequence and a frequency domain. Receive timeslots. When the guard interval separator 1020 removes the guard interval from the timeslot, the symbol processor 1030 uses the timeslot from which the guard interval has been removed to form the first multisymbol sequence and the pilot symbol sequence. The control symbol sequence and the data symbol sequence are divided in the frequency domain from the first multisymbol sequence.

The symbol processing unit 1030 demodulates the control symbol sequence first to remove the influence of the control symbol sequence on the pilot symbol sequence first and then receives the pilot symbol sequence.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

As proposed in the present invention, pilot symbols, control symbols, and data symbols are separately transmitted in terms of time, that is, channel estimation values and control information necessary before demodulation of data symbols are received and demodulated to demodulate data symbols. There is an effect such as reducing the delay. In addition, the time slot is variably set in consideration of a channel state, that is, a dedicated service and a common service, and thus has an advantage of increasing the overall service quality in response to the service. In addition, by applying a variable time slot structure according to a symbol to be transmitted, it has an effect corresponding to a real-time service.

Claims (60)

In the method for transmitting data in a mobile communication system supporting multiple carriers, Generating at least one type of symbol string among a data symbol sequence, a pilot symbol sequence, and a control symbol sequence for the data symbol sequence; Concatenating at least one guard interval to prevent adjacent symbol interference to the generated symbol sequence; And transmitting a time slot comprising the at least one guard period and the generated symbol string. Wherein the configuration format of the timeslot is variable. The method of claim 1, The configuration format of the timeslot may vary depending on the length or existence of at least one symbol string among the length of the data symbol string, the length of the pilot symbol string, and the length of the control symbol string. The method of claim 2, The length of the symbol strings and the guard interval is variable according to the channel state. The method of claim 1, And a plurality of time slots constitute one transmission time interval (TTI), wherein the configuration format for each time slot is variable within the transmission time interval. The method of claim 1, And the data type of the data symbol string is set for each timeslot. The method of claim 1, wherein the transmitting of the The method as claimed in claim 1, wherein the data symbol string having a different FFT size is transmitted for each timeslot. The method of claim 11, wherein the transmitting step, And transmitting the generated symbol sequences sequentially in the time domain or in parallel in the frequency domain. The method of claim 11, wherein the transmitting step, And transmitting the control symbol sequence or the pilot symbol sequence sequentially in the time domain and transmitting the data symbol sequence in parallel in the frequency domain. The method of claim 1, wherein the transmitting of the And transmitting the control symbol sequence sequentially in the time domain and transmitting the pilot symbol sequence or the data symbol sequence in parallel in the frequency domain. An apparatus for transmitting data in a mobile communication system supporting multiple carriers, A symbol generator for generating at least one type of symbol string among a data symbol sequence, a pilot symbol sequence, and a control symbol sequence for the data symbol sequence; A guard interval insertion unit for connecting at least one guard interval to prevent adjacent symbol interference to the generated symbol string; Comprising a transmission unit for transmitting a time slot consisting of the at least one guard interval and the generated data symbol string, Wherein the configuration format of the timeslot is variable. The method of claim 10, The configuration format of the timeslot may vary depending on the length or existence of at least one symbol string among the length of the data symbol string, the length of the pilot symbol string, and the length of the control symbol string. The method of claim 11, The length of the symbol strings and the guard interval is variable according to the channel state. The method of claim 10, And a plurality of time slots constitute one transmission time interval (TTI), wherein each time slot configuration format is variable within the transmission time interval. The method of claim 10, And a data type of the data symbol string is set for each timeslot. The method of claim 10, wherein the transmission unit, And transmitting the data symbol string having a different FFT size for each timeslot. The method of claim 10, wherein the transmission unit, And transmitting the generated symbol sequences sequentially in the time domain or in parallel in the frequency domain. The method of claim 10, wherein the transmission unit, And transmitting the control symbol sequence or the pilot symbol sequence sequentially in the time domain and transmitting the data symbol sequence in parallel in the frequency domain. The method of claim 10, wherein the transmission unit, And transmitting the control symbol sequence sequentially in the time domain and transmitting the pilot symbol sequence or the data symbol sequence in parallel in the frequency domain. In the method for receiving data in a mobile communication system supporting multiple carriers, Receiving a time slot comprising at least one type of symbol string of a data symbol sequence, a pilot symbol sequence, and a control symbol sequence for the data symbol sequence, and at least one guard interval for preventing adjacent symbol interference; Separating the at least one guard period from the time slot to distinguish the at least one type of symbol string, Wherein the configuration format of the timeslot is variable. The method of claim 19, The configuration format of the timeslot may vary depending on the length or existence of at least one symbol string among the length of the data symbol string, the length of the pilot symbol string, and the length of the control symbol string. The method of claim 20, The length of the symbol strings and the guard interval is variable according to the channel state. The method of claim 19, And a plurality of time slots constitute one transmission time interval (TTI), wherein the configuration format for each time slot is variable within the transmission time interval. The method of claim 19, And the data type of the data symbol string is set for each timeslot. The method of claim 19, wherein the receiving process, And receiving the data symbol string having a different FFT size for each timeslot. The method of claim 19, The symbol sequence may be received sequentially in the time domain or in parallel in the frequency domain. The method of claim 19, The control symbol sequence or the pilot symbol sequence are sequentially received in the time domain, and the data symbol sequence is received in parallel in the frequency domain. The method of claim 19, The control symbol sequence is sequentially received in the time domain, and the pilot symbol sequence or the data symbol sequence are received in parallel in the frequency domain. The method of claim 19, wherein the receiving process, And demodulating the control symbol sequence first to remove the influence of the control symbol sequence on the pilot symbol sequence and then receiving the pilot symbol sequence. The method of claim 19, And demodulating the data symbol sequence after first removing the influence of the control symbol sequence or the pilot symbol sequence on the data symbol sequence. An apparatus for receiving data in a mobile communication system supporting multiple carriers, A receiving unit for receiving a time slot including at least one kind of symbol string among a data symbol sequence, a pilot symbol sequence, and a control symbol sequence for the data symbol sequence, and at least one guard interval for preventing adjacent symbol interference; In order to obtain the at least one kind of symbol string, it consists of a guard interval separating unit for separating the at least one guard interval in the time slot, Wherein the configuration format of the timeslot is variable. The method of claim 30, The configuration format of the timeslot may vary depending on the length or existence of at least one symbol string among the length of the data symbol string, the length of the pilot symbol string, and the length of the control symbol string. The method of claim 31, wherein The length of the symbol strings and the guard interval is variable according to the channel state. The method of claim 30, And a plurality of time slots constitute one transmission time interval (TTI), wherein the configuration format for each time slot is variable within the transmission time interval. The method of claim 30, And a data type of the data symbol string is set for each timeslot. The method of claim 30, wherein the receiving unit, And receiving the data symbol string having a different FFT size for each timeslot. The method of claim 30, The symbol strings are received sequentially in the time domain or in parallel in the frequency domain. The method of claim 30, The control symbol sequence or the pilot symbol sequence are sequentially received in the time domain, and the data symbol sequence is received in parallel in the frequency domain. The method of claim 30, The control symbol sequence is sequentially received in the time domain, and the pilot symbol sequence or the data symbol sequence is received in parallel in the frequency domain. The method of claim 30, And a symbol processor which demodulates the data symbol sequence after first removing the influence of the control symbol sequence or the pilot symbol sequence on the data symbol sequence. The method of claim 39, wherein the symbol processing unit, And demodulating the control symbol sequence first to remove the influence of the control symbol sequence on the pilot symbol sequence first and then receiving the pilot symbol sequence. In a method of transmitting data in a mobile communication system supporting multiple carriers, Generating a first multi-symbol sequence obtained by multiple mapping of the control symbol sequence from the data symbol sequence to the frequency domain; Generating a predetermined pilot symbol string; And separating and transmitting the first multi-symbol sequence and the pilot symbol sequence in a time domain. The method of claim 1, wherein at least one guard interval for contiguous adjacent symbol interference is contiguously transmitted to the first multisymbol sequence and the pilot symbol sequence, and the lengths of the symbol sequences and the guard interval are variable. 42. The method of claim 41 wherein The pilot symbol sequence and the data symbol sequence are mapped to a predetermined part in the frequency domain and transmitted. 42. The method of claim 41 wherein The configuration format of the timeslot may vary depending on the length or existence of at least one symbol string among the length of the data symbol string, the length of the pilot symbol string, and the length of the control symbol string. The method of claim 43, The length of the symbol strings and the guard interval is variable according to the channel state. 42. The method of claim 41 wherein And a plurality of time slots constitute one transmission time interval (TTI), wherein the configuration format for each time slot is variable within the transmission time interval. 42. The method of claim 41 wherein And the data type of the data symbol string is set for each timeslot. 42. The method of claim 41, wherein the transmitting step, The method as claimed in claim 1, wherein the data symbol string having a different FFT size is transmitted for each timeslot. 42. The method of claim 41, wherein the transmitting step, And transmitting the generated symbol sequences sequentially in the time domain or in parallel in the frequency domain. 42. The method of claim 41, wherein the transmitting step, And transmitting the control symbol sequence or the pilot symbol sequence sequentially in the time domain and transmitting the data symbol sequence in parallel in the frequency domain. 42. The method of claim 41, wherein the transmitting step, And transmitting the control symbol sequence sequentially in the time domain and transmitting the pilot symbol sequence or the data symbol sequence in parallel in the frequency domain. In the method for receiving data in a mobile communication system supporting multiple carriers, Receiving a time slot configured by concatenating at least one guard interval for preventing adjacent symbol interference to a first multi-symbol sequence and a pilot symbol sequence in which a control symbol sequence is multi-mapped in a data symbol sequence and a frequency domain; Removing the at least one guard period from the timeslot, The first multi-symbol sequence and the pilot symbol sequence are partitioned in the time domain using the timeslot from which the guard interval has been removed, and the control symbol sequence and the data symbol sequence are partitioned in the frequency domain from the first multi-symbol sequence. It consists of the process of Wherein the length of the symbol strings and the guard interval is variable. The method of claim 51, wherein The pilot symbol sequence and the data symbol sequence are mapped to a predetermined part in the frequency domain and received. The method of claim 51, wherein The configuration format of the timeslot may vary depending on the length or existence of at least one symbol string among the length of the data symbol string, the length of the pilot symbol string, and the length of the control symbol string. The method of claim 51, wherein The length of the symbol strings and the guard interval is variable according to the channel state. The method of claim 51, wherein And a plurality of time slots constitute one transmission time interval (TTI), wherein the configuration format for each time slot is variable within the transmission time interval. The method of claim 51, wherein And the data type of the data symbol string is set for each timeslot. 52. The method of claim 51, wherein said receiving is: And receiving the data symbol string having a different FFT size for each timeslot. The method of claim 51, wherein The generated symbol strings are sequentially transmitted in the time domain or in parallel in the frequency domain. The method of claim 51, wherein The control symbol sequence or the pilot symbol sequence are sequentially received in the time domain, and the data symbol sequence is received in parallel in the frequency domain. The method of claim 51, wherein The control symbol sequence is sequentially received in the time domain, and the pilot symbol sequence or the data symbol sequence are received in parallel in the frequency domain.

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