KR101537617B1 - Method for transmitting signal in wireless communication system - Google Patents

Abstract

A method for transmitting a signal using a predetermined frame structure in a wireless communication system is disclosed. The UE can transmit / receive a signal using a frame structure having a CP length corresponding to 1/4 of the effective symbol length. Also, a frame structure having a CP length corresponding to 1/4 of the effective symbol length designed to coexist with each other can be used to transmit / receive signals without causing collision or interference with a frame structure having a different CP length. At this time, the channel bandwidth of the predetermined frame structure is 8.75 MHz.

Frame structure, CP length

Description

TECHNICAL FIELD [0001] The present invention relates to a method for transmitting a signal in a wireless communication system,

The present invention relates to a signal transmission method, and more particularly, to a method for transmitting a signal using a predetermined frame structure in a wireless communication system.

The IEEE 802.16m system can support both a Frequency Division Duplex (FDD) scheme and a Time Division Duplex (TDD) scheme including an operation of an H-FDD (Half-Frequency Division Duplex) terminal. The IEEE 802.16m system uses Orthogonal Frequency Division Multiplexing Access (OFDMA) as a multiple access method in a downlink and an uplink. The contents of the OFDMA parameters are shown in Table 1 below.

Hereinafter, a frame structure of the IEEE 802.16m system will be briefly described.

1 is a diagram showing a basic frame structure in an IEEE 802.16m system.

Referring to FIG. 1, each 20 ms superframe is divided into four equal-sized 5 ms radio frames, and the superframe starts with a super frame header (SFH). When using the same OFDMA parameters as shown in Table 1 with either channel bandwidth of 5 MHz, 10 MHz or 20 MHz, each 5 ms radio frame is composed of 8 subframes. One subframe may be allocated for downlink or uplink transmission. The first type is a subframe composed of six OFDMA symbols, the second type subframe is a subframe consisting of seven OFDMA symbols, and the third type subframe is a subframe composed of six OFDMA symbols.

The basic frame structure can be applied to both the FDD method and the TDD method including the operation of the H-FDD terminal. In the TDD system, the number of switching points in each radio frame is two. The switching points may be defined according to the change of direction from the downlink to the uplink or from the uplink to the downlink.

The H-FDD terminal can be included in the FDD system, and the frame structure in terms of the H-FDD terminal is similar to the TDD frame structure. However, the downlink and uplink transmissions occur in two separate frequency bands. The transmission gaps between the downlink and the uplink (and vice versa) are required to switch the transmit and receive circuits.

2 is a diagram illustrating an example of a TDD frame having a downlink and uplink ratio of 5: 3.

Referring to FIG. 2, assuming that the OFDMA symbol period has a symbol duration of 102.857 μs and a length corresponding to 1/8 of an effective symbol length (Tu) as a CP (Cyclic Prefix) length, The lengths of the 3 type sub-frames are 0.617 ms and 0.514 ms, respectively. And the last downlink subframe SF4 is a third type subframe. The Transition Transition Gaps (TTG) and the Receive Transition Gaps (RTG) are 105.714 μs and 60 μs, respectively. In other numerology, the number of subframes per frame and the number of symbols in a subframe may be different.

3 is a diagram showing an example of a frame structure in the FDD scheme.

Referring to FIG. 3, a base station supporting the FDD scheme can simultaneously support half-duplex and full-duplex terminals operating on the same RF carrier. A terminal supporting the FDD scheme should use either the H-FDD scheme or the FDD scheme. All subframes are available for transmission in both the downlink and the uplink. The downlink and uplink transmissions may be separated in the frequency domain. One superframe is divided into four frames, and one frame consists of eight subframes.

4 is a diagram illustrating a TDD and FDD frame structure having a CP length corresponding to 1/16 of an effective symbol length Tu.

Referring to FIG. 4, for a channel bandwidth of 5 MHz, 10 MHz, and 20 MHz, a frame of an IEEE 802.16m system having a CP length corresponding to 1/16 of an effective symbol length Tu is divided into five first type sub- Frame and three second subframes, and has six first type subframes and two second type subframes in the TDD scheme.

Assuming that the OFDMA symbol duration is 97.143 mu s and the CP length is 1/16 of the effective symbol length Tu, the lengths of the first type subframe and the second type subframe are 0.583 ms and 0.680 ms. TTG and RTG are 82.853 μs and 60 μs, respectively. In other numerology, the number of subframes per frame and the number of symbols in a subframe may be different.

As described above, the IEEE 802.16m system defines only the OFDMA parameters and the frame structure for the case where the CP length is 1/8 Tb and 1/16 Tb for the 5 MHz, 10 MHz, and 20 MHz channel bandwidths. That is, the frame structure for the CP length of 1/4 Tb has not been proposed so far.

Also, in the case of a frame structure having a CP length of 1/4 Tb, a frame structure having a CP length of 1/8 Tb or 1/16 Tb and a problem in which interference occurs at switching points between downlink and uplink There is a problem that can occur. However, there has been no proposal for a new frame structure capable of solving these problems and mutual coexistence.

Also, in the IEEE 802.16m system, only OFDMA parameters and frame structure of 1/8 Tb and 1/16 Tb are defined for the 8.75 MHz band, and 1/4 Tb is not defined yet. In case of using a frame structure having a CP length of 1/4 Tb, if the idle period for the TTG / RTG is set as in the conventional case, the CP length (1/8 Tb and 1/16 Tb CP Length) than that of the frame structure having the TTG / RTG, it is necessary to solve the problem.

SUMMARY OF THE INVENTION The present invention provides a signal transmission method in a wireless communication system.

The technical problems to be solved by the present invention are not limited to the technical problems and other technical problems which are not mentioned can be understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a signal transmission method including: receiving a signal from a base station using a predetermined frame structure; And transmitting a signal to the base station using the predetermined frame structure. In the predetermined frame structure, one frame is composed of six subframes, and each subframe includes six OFDMA (Orthogonal Frequency Division Multiple Access) symbol or a second type subframe consisting of 7 OFDMA symbols.

The predetermined frame may be a Time Division Duplex (TDD) frame or a Frequency Division Duplex (FDD) frame.

In addition, the TTD frame includes a downlink interval and an uplink interval subsequent to the downlink interval. In a first subframe of the downlink interval and a first subframe of the uplink interval, . In the TDD frame, a second type subframe is located in a second subframe of the downlink interval and a second subframe of the uplink interval.

In addition, in the TTD frame, a transmission transition gap (TTG) is located between the downlink section and the uplink section and a receive transition gap (RTG) after the last subframe of the uplink section. And the TTD frame is composed of four first type subframes and two second type subframes.

Preferably, the ratio of the number of downlink subframes to the number of uplink subframes in the TTD frame is any one of 5: 1, 4: 2, 3: 3, and 2: 4.

In the FDD frame, the second type subframe is located in the same order as the last subframe of the downlink in the TDD frame, and the second type subframe is located in the fourth subframe in the FDD frame .

In addition, the FDD frame is composed of three first type subframes and three second type subframes, and an idle time is preferably located after the last subframe in the FDD frame.

In addition, the CP length of the predetermined frame is 1/4 of the effective symbol length, and the predetermined frame structure has a channel bandwidth of 8.75 MHz.

According to the present invention, signals can be transmitted and received using a TDD frame structure having a CP length corresponding to 1/4 of an effective symbol length and an FDD frame structure having a commonality with the TDD frame structure.

According to the present invention, signals can be transmitted and received using a TDD frame structure having a different CP length and a TDD frame structure capable of mutually coexisting.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The detailed description set forth below in conjunction with the appended drawings is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details for a better understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details. For example, in the following description, certain terms are mainly described, but they need not be limited to these terms, and they may have the same meaning when they are referred to as arbitrary terms. Further, the same or similar elements throughout the present specification will be described using the same reference numerals.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

The techniques described below may be used in various communication systems, which may provide various communication services such as voice, packet data, and so on. The technology of the communication system can be used for a downlink or an uplink. The base station may be replaced by terms such as a fixed station, a base station, a Node B, an eNode B (eNB), an access point, an ABS, and the like. In addition, a mobile station (MS) can be replaced with terms such as a UE (User Equipment), a Subscriber Station (SS), a Mobile Subscriber Station (MSS), an AMS or a Mobile Terminal.

Also, the transmitting end refers to a node that transmits data or voice service, and the receiving end refers to a node that receives data or voice service. Therefore, in the uplink, the terminal may be the transmitting end and the base station may be the receiving end. Similarly, in the downlink, the terminal may be the receiving end and the base station may be the transmitting end.

The terminal of the present invention may be a PDA (Personal Digital Assistant), a cellular phone, a PCS (Personal Communication Service) phone, a GSM (Global System for Mobile) phone, a WCDMA (Wideband CDMA) Can be used.

Embodiments of the present invention may be implemented in accordance with standard documents disclosed in at least one of the Institute of Electrical and Electronics Engineers (IEEE) 802 systems, 3GPP systems, 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) systems and 3GPP2 systems It can be backed up. That is, the steps or portions of the embodiments of the present invention that are not described in order to clearly illustrate the technical idea of the present invention can be supported by the documents. In addition, all terms disclosed in this document may be described by the standard document. In particular, embodiments of the present invention may be supported by documents such as P802.16-2004, P802.16e-2005 and P802.16Rev2, which are standard documents of the IEEE 802.16 system.

The specific terminology used in the following description is provided to aid understanding of the present invention, and the use of such specific terminology may be changed into other forms without departing from the technical idea of the present invention.

A basic principle of Orthogonal Frequency Division Multiplexing (OFDM), which is a multicarrier modulation scheme in a wireless communication system, will be described as follows.

In an OFDM system, a data stream having a high-rate is divided into a large number of data streams having a slow-rate, which is transmitted simultaneously using a plurality of carriers. Each of the plurality of carriers is referred to as a subcarrier. Since orthogonality exists among a plurality of carriers in an OFDM system, even if frequency components of carriers overlap each other, detection at the receiving end is possible. A data stream having a high-speed data rate is converted into a data stream having a plurality of low data rates through a serial-to-parallel (S / P) converter, and a plurality of data streams, And then the data streams may be combined and transmitted to the receiving end.

The plurality of parallel data streams generated by the serial-to-parallel conversion unit may be transmitted on a plurality of subcarriers by inverse discrete Fourier transform (IDFT). At this time, the IDFT can be efficiently implemented using Inverse Fast Fourier Transform (IFFT). Since the symbol duration of a sub-carrier having a low data rate is increased, the relative signal dispersion in time caused by multipath delay spreading is reduced.

In wireless communication using the OFDM scheme, a guard interval longer than a delay spread of a channel between symbols may be inserted to reduce inter-symbol interference. That is, while each symbol is transmitted through the multipath channel, a guard interval longer than the maximum delay spread of the channel is inserted between consecutive symbols. At this time, in order to prevent the orthogonality destruction between the subcarriers, the signal of the last interval (i.e., guard interval) of the valid symbol interval is copied and inserted in the front part of the symbol. This is referred to as a cyclic prefix (CP).

5 is a diagram illustrating an example of a symbol structure including a CP (cyclic prefix).

Referring to FIG. 5, the symbol period Ts is the sum of the effective symbol period Tb and the guard period Tg at which the actual data is transmitted. At the receiving end, demodulation is performed by taking the data during the effective symbol interval after removing the guard interval. The transmitting end and the receiving end can be synchronized with each other using the cyclic prefix, and orthogonality between the data symbols can be maintained. The symbol referred to in the present invention may be an OFDMA symbol.

A frame structure in an 802.16m system having a CP length (hereinafter referred to as a CP length of 1/4 Tb) corresponding to 1/4 of an effective symbol length in a channel bandwidth of 8.75 MHz (a TDD frame and an FDD frame Will be described. A TDD frame structure having a CP length of 1/8 Tb or a CP length of 1/16 Tb and a TDD frame structure capable of mutually coexisting with respect to the same channel bandwidth of 8.75 MHz will be described. The FDD frame structure having many similarities with the TDD frame structure proposed by the present invention will also be described.

There are four types of subframes in the IEEE 802.16m system. The first type is a subframe consisting of six OFDMA symbols, the second type subframe is a subframe consisting of seven OFDMA symbols, the third type subframe is a subframe consisting of six OFDMA symbols, the fourth type subframe is It can be defined as a subframe consisting of nine OFDMA symbols. At this time, the fourth type subframe can be used in a frame structure in a channel bandwidth of 8.75 MHz.

As shown in Table 1, when the CP length of 1/4 Tb is used in the channel bandwidth of 8.75 MHz, the OFDMA parameters defined are defined in the same manner as the conventional CP length of 1/8 Tb or 1/16 Tb of CP length . The symbol period of OFDM is 128 μs and the relative transmission gap (TTG) and receive transition gap (RTG) are 61.6 μs and 74.4 μs, respectively, when the CP length is 1/4 Tb. Considering the defined OFDMA parameters, the number of symbols in one frame is 39 when a CP length of 1/4 Tb is used. A frame structure having a CP length of 1/4 Tb may be formed using the first to third type subframe types according to the number of symbols used to define the subframe in the existing frame structure. The number of symbols in a frame having a CP length of 1/4 Tb is 39.

If a frame is composed of seven subframes as in the conventional CP length of 1/8 Tb and the CP length of 1/16 Tb, one symbol can be allocated to the TTG and RTG periods in the TDD frame structure, And the remaining 38 OFDMA symbols can be allocated to the downlink and uplink. At this time, the TDD frame may be composed of three first type subframes and four third type subframes.

6 to 10 show an example of a TDD frame structure having a CP length of 1/4 Tb that can coexist with a TDD frame structure having a different CP length according to the number of downlink subframes and the number of uplink subframes, Fig.

6 to 10, the ratio of the number of downlink subframes to the number of uplink subframes is 2: 5, 3: 4, 4: 3, 5: 2, : 1). When the ratio of the number of downlink subframes to the number of uplink subframes is (2: 5), (3: 4), (4: 3), (5: 2) When communication is performed using a frame structure having a CP length of 1/4 Tb in a channel bandwidth of 8.75 MHz, a frame having a CP length of 1/8 Tb and a CP length of 1/16 Tb and a downlink / Interference does not occur. Therefore, frame structures having different CP lengths can coexist.

Two first type subframes among three first type subframes must be located at positions which are not affected by the ratio of the number of downlink subframes and the number of uplink subframes, Th < / RTI > subframe and the last subframe in the uplink. However, this is merely an example, and in all cases the first type subframe is not located in this way. The first subframe of the downlink and uplink may be configured as a first type subframe including six symbols, and the downlink and uplink may be configured to start with the first type subframe. The remaining one type 1 sub-frame can be located in the downlink subframe or the uplink subframe considering the ratio of the number of downlink subframes to the number of uplink subframes. .

The last subframe of the downlink, which is located in the downlink to uplink subframe, is generally composed of six symbols including an idle period. However, the time difference (or delay) required for the TTG period is usually To make it, one symbol can be composed of five symbols with idle intervals. This configuration can be applied regardless of the ratio of the number of downlink subframes to the number of uplink subframes. In the TDD frame, one symbol may be allocated as an idle period of the TTG / RTG.

In addition, when two first type subframes are located in the downlink region, one first type subframe is divided into a first subframe of the first subframe and a second subframe of the second subframe in order to use a superframe header (SFH) Frame. If the first type subframe is located in the last subframe of the downlink, the last subframe of the downlink includes one symbol May be allocated to an idle period and may be configured with six symbols. This configuration is applicable when the ratio of the number of downlink subframes to the number of uplink subframes is (4: 3), (5: 2), and (6: 1). In this case, two first type subframes may be located in the downlink region to coexist with a frame structure having a different CP length without interference. Such a TDD frame structure is shown in FIGS. 8 to 10. FIG.

Also, when the first type subframe is located in the first subframe of the downlink subframe, the first type subframe other than the above-described content may be located in any subframe in the downlink region.

In all the above-described frame configuration examples, one type 1 sub-frame in the downlink and uplink sections is located in the first sub-frame of the downlink and the last sub-frame of the uplink in the TDD frame, It is possible to solve the interference problem that may occur in the switching period from the downlink to the uplink as described above.

As shown in FIGS. 6 to 10, a first type subframe is located in the first subframe of the downlink and the last subframe of the uplink in the TDD frame, or a first type subframe is located in the first subframe of the downlink and the uplink. The location of the type sub-frame is merely an example for coexistence with a conventional frame structure having a different CP length. That is, a subframe including six symbols may be located in an arbitrary subframe in an area of a downlink or an uplink. 6 to 10, even if the first type sub-frame is located in the first sub-frame of the downlink and the second type sub-frame is located in the second sub-frame in the frame structure having the conventional 1/16 Tb CP length, The TDD frame structure of the present invention proposed in FIG. 10 can coexist with the conventional frame structure having a CP length of 1/8 Tb and 1/16 Tb.

11 is a diagram showing an example of an FDD frame structure having a CP length of 1/4 Tb.

The FDD frame structure shown in FIG. 11 is a frame structure corresponding to the TDD frame structure shown in FIGS. 6 to 10, and may have a commonality with this TDD frame structure. Designing to have commonality with the TDD frame structure has the advantage of reusing essential control information in the physical layer design considered in system design, and channel design for additional control information. Therefore, it is preferable that the FDD frame structure is constructed by inheriting the TDD frame structure. 39 symbols may be allocated to the FDD frame.

The basic structure of the FDD frame may be composed of 7 subframes as in the TDD frame structure shown in FIG. 6 to FIG. 10, and 39 symbols may be allocated. It may be desirable to maintain the commonality that the first type subframe is located in the first subframe and the last subframe in the FDD frame. In the TDD frame structure, when the first type subframe is located in the downlink and uplink areas and the first subframe of each area is located, 6 symbols can be allocated in the same manner as in the existing structure. In this case, the first type sub-frame further disposed in each area may be located in any sub-frame without limitation in position within each area. That is, since the first type subframe is located in the second subframe in FIG. 11, it is not limited to the position of the first type subframe in the downlink and uplink regions .

In the FDD frame structure, since a TTG / RTG like the TDD frame structure is not necessary, one symbol can be further utilized. Therefore, it is conceivable to construct a second type sub-frame or a first type sub-frame by adding one remaining symbol to the first type sub-frame or the third type sub-frame. A position for a subframe to which one symbol can be additionally allocated may be a third subframe, a fourth subframe or a fifth subframe in the FDD frame shown in cases 1, 2, 3 and 4 in FIG. 11 . Considering the H-FDD frame structure, additional idle intervals are required between groups when considering the H-FDD frame structure. To this end, it is possible to construct such additional sections using a first type sub-frame or a second type sub-frame. However, this is only one example of the position to be considered, and there is no limitation on the position of the first type sub frame or the second type sub frame to which one symbol is added.

As another method, there is a method of individually allocating one remaining symbol. As shown in Case 5 in FIG. 11, one additional symbol of the first subframe in the FDD frame may be added. This is because the essential control information for each symbol unit such as a preamble or a frame control header (FCH) is transmitted in the front part of the frame, so that the control information is transmitted and a first type Subframes can be used. Alternatively, as shown in case 8 of FIG. 11, one symbol can be allocated to the last subframe of the FDD frame and used to transmit additional information such as sounding.

In addition, when considering the H-FDD frame structure, it is preferable that one symbol position is located in the front part or the rear part in the fourth sub-frame. However, this is only one example of a preferable position, and there is no limitation in the position of one symbol to be added in the present invention.

As described above, when one frame is composed of seven subframes, two first type subframes may be located in the first subframe and the last subframe in the frame. The remaining one first type subframe may be located in the second subframe or may be located in any subframe in the downlink interval.

12 to 16 are diagrams showing an example of a TDD frame structure having a CP length of 1/4 Tb that can coexist with a frame structure having a different CP length according to the number of downlink subframes and the number of uplink subframes, respectively to be.

12 to 16, the ratio of the number of downlink subframes to the number of uplink subframes is (2: 5), (2: 4), (3: 4) 4: 3), (5: 2), (4: 2), (6: 1), and (5: 1). 12, when the ratio of the number of downlink subframes to the number of uplink subframes is (2: 5) and (2: 4), the total number of symbols allocated to the downlink subframes and the number of uplink subframes (12:26) of the total number of symbols assigned to the base station. 13, when the ratio of the number of downlink subframes to the number of uplink subframes is (3: 4) and (3: 3), the total number of symbols allocated to the downlink subframes and the number of uplink subframes The ratio of the total number of symbols allocated to the base station is 17:21. 14, when the ratio of the number of downlink subframes to the number of uplink subframes is (4: 3) and (3: 3), the total number of symbols allocated to the corresponding downlink subframes The ratio of the total number of symbols allocated to the UL subframes is (22:16) and (21:17), respectively. 15, when the ratio of the number of downlink subframes to the number of uplink subframes is (5: 2) and (4: 2), the total number of symbols allocated to the corresponding downlink subframes and the uplink The ratios of the total number of symbols allocated to the subframes are (27:11) and (26,12), respectively. 16, when the ratio of the number of downlink subframes to the number of uplink subframes is (6: 1), the total number of symbols allocated to the downlink subframes and the total number When the ratio of the number of symbols to the number of downlink subframes is (32: 6) and the ratio of the number of downlink subframes to the number of uplink subframes is (5: 1), the total number of symbols allocated to the downlink subframes, The ratio of the total number of symbols assigned to the frames is (31: 7) or (32: 6).

In order to coexist with a frame structure having a CP length of 1/16 Tb as defined above, it is necessary to prevent overlapping of downlink / uplink switching points. To this end, a CP length of 1/4 Tb Can be considered to constitute six subframes. In the TDD frame, one symbol can be allocated for the TTG / RTG interval, and the remaining 38 symbols can constitute a TDD frame composed of 6 subframes as shown in the following two cases.

As a first case, a TDD frame can be composed of four second type subframes and two third type subframes. In the second case, the TDD frame can be composed of four first type subframes and two second type subframes.

In the TDD frame structure, the first type subframe or the second type subframe may be located in the last subframe of the downlink, which is a transition period from the DL to the UL, considering the idle period. If the second type subframe is located in the last subframe of the downlink, a new type subframe consisting of 8 symbols including the idle period is generated, which is out of the range of the previously defined subframe. Therefore, a definition of a new type of subframe is needed.

If a second type subframe considering an idle interval period is allocated to the last subframe of the downlink located in the downlink to uplink subframe, one symbol may be set as the idle period for the delay required for the TTG interval . Accordingly, a first type subframe including six symbols may be located in the last subframe of the downlink. Here, the first type subframe may be located in the first subframe and the last subframe in the frame in the downlink area. This configuration can be applied regardless of the ratio of the number of downlink subframes to the number of uplink subframes.

In the case of constructing one frame using six subframes as in the first case above in order to coexist with a frame structure having a CP length of 1/16 Tb as defined above, The third type subframe may be located in the last subframe of the downlink regardless of the ratio of the number of downlink subframes to the number of uplink subframes. 14, when the ratio of the number of downlink subframes to the number of uplink subframes is (3: 3), a new type subframe consisting of 8 symbols is located in the last subframe of the downlink .

In a second case where a frame is composed of a first type subframe and a second type subframe, when a first type subframe is located in a first subframe of a downlink and an uplink region, The first type subframe or the second type subframe may be located in the last subframe of the downlink, which is a switching period for the first type subframe or the second type subframe. If one symbol allocated for the idle time of the switching period is considered, a subframe consisting of seven or eight symbols may be located in the last subframe of the downlink. Here, the two second type subframes constituting the TDD frame may be located in the downlink and uplink areas in order to coexist with the previously-defined frame structure having the CP length of 1/16 Tb, without interference. An example is shown in Figs. 12, 15 and 16. Fig. Here, the positions of the first type subframe and the second type subframe are examples, and there is no limitation on the position of each type of subframe in the downlink and uplink areas.

12 to 16 show a frame structure having a CP length of 1/16 Tb using seven previously defined subframes and a frame structure for coexistence without interfering with each other. In Fig. 12 to Fig. 16, when one frame is composed of six subframes, placing the second type subframe in the first subframe and the last subframe in the frame, or in the downlink and uplink sections, A subframe consisting of seven symbols may be located in any subframe within the respective areas of the downlink or uplink.

17 is a diagram showing an example of an FDD frame structure having a CP length of 1/4 Tb.

The FDD frame structure shown in FIG. 17 is a frame structure corresponding to the TDD frame structure shown in FIG. 12 to FIG. The frame structure for the FDD is preferably constructed by inheriting the TDD structure, and the FDD frame structure can be appropriately constructed by applying the FDD frame structure for each case described above. 12 to 16, and the FDD structure for the case where the first type subframe is located in the second subframe of the frame is the same as that of the TDD frame structure shown in FIG. 11 Frame structures such as FDD-cases 4 to 9 may be considered.

Also, when one frame is composed of six subframes, as shown in FIGS. 12 to 16, the FDD frame may be composed of six subframes as in the conventional TDD frame structure, The second type subframe may be located in the subframe and the last subframe, and the second type subframe may be located in the second and fifth subframes to maintain a symmetric structure.

39 symbols may be allocated to the FDD frame shown in FIG. Since the TTG / RTG is not required in the FDD frame structure, unlike the TDD frame structure, an additional symbol can be further used. Therefore, it can be considered to configure the first type subframe by adding the remaining symbols to the third type subframe. A subframe in which one symbol is added may be located in a third subframe or a fourth subframe in a frame as shown in cases 1 through 4 of FIG.

However, in consideration of the H-FDD frame structure, when considering the H-FDD structure, an additional idle period is required between the groups. To this end, the first type subframe or the second type subframe is used, . ≪ / RTI > In addition, in the present invention, the position of the first type sub frame or the second type sub frame to which one symbol is added is not limited.

As another method of allocating an additional symbol, there is a method of individually allocating the symbols. The position of this symbol is shown in cases 1 to 4 of FIG. 17 described above for H-FDD, where it is preferably located between the third subframe and the fourth subframe. However, this is a preferable position, but there is no limitation on the position of one symbol added in the present invention. Therefore, as in the FDD frame structure described above, one symbol can be individually assigned to the first sub-frame or the last sub-frame within the frame.

18 is a diagram showing an example of a TDD frame structure having a CP length of 1/4 Tb.

Referring to FIG. 18, when one TDD frame is composed of six subframes, a first type subframe consisting of six symbols can be allocated to form a frame. At this time, one TTD frame may be composed of four first type subframes and two second type subframes. At this time, it is preferable that the two second type subframes are located at positions which are not influenced by the ratio of the number of downlink subframes and the number of uplink subframes, respectively. Therefore, in one frame, And may be located in the last subframe. As described above, the second type subframe is located in the first subframe of the downlink and the last subframe of the uplink, and there is no limitation on the position of the second type subframe.

Therefore, when considering the ratio of the number of downlink subframes to the number of uplink subframes having the number of downlink subframes of at least two, the second type subframe may be located in the second subframe in the frame. As described above, the first type subframe may be arranged at the position of the first subframe in the downlink and uplink areas to form a frame. Since the first type subframe having six symbols is located in the first subframe in the frame, the superframe header structure defined by six symbols can be inherited without changing the subframe structure.

The last subframe of the downlink located in the downlink to uplink transition period is a subframe consisting of 7 symbols including the idle period. Generally, in order to make a time difference necessary for the TTG period, one symbol is used as an idle period And the subframe can be composed of six symbols. This configuration can be applied regardless of the ratio of the number of downlink subframes to the number of uplink subframes.

18, a frame structure in which the second type subframe is located in the first subframe and the last subframe in the frame, and a frame structure in which the first type subframe is located in the first subframe of the downlink and uplink angular regions, . The frame structure shown in Fig. 18 is only an example, and the positions of the first type sub frame and the second type sub frame for constituting one frame are not limited.

19 is a diagram showing an example of an FDD frame structure having a CP length of 1/4 Tb.

The FDD frame structure of FIG. 19 corresponds to the frame structure corresponding to the TTD frame structure shown in FIG. The FDD frame structure is preferably constructed by inheriting the TDD frame structure. It is possible to consider an appropriate FDD frame structure by applying the FDD frame structure according to each case. As shown in FIG. 18, the second type subframe may be located in the first subframe, the second subframe, or the last subframe within the frame. In addition, the first type subframe may be arranged in the first subframe of each downlink and uplink area.

In this case, unlike the TDD frame structure in the FDD frame structure, since a TTG / RTG section is not necessary, one symbol can be additionally utilized. Therefore, it may be considered to configure the second type subframe by adding the remaining symbols to the first type subframe. The subframe located in the added symbol may be located in the third or fourth subframe in the frame as in cases 1 and 2 in Fig. Considering the H-FDD frame structure, an additional idle period is required between the groups in consideration of the H-FDD frame structure. To this end, an additional interval required by the second type sub-frame can be configured. However, this is a position to be considered, but in the present invention, the position of the second type subframe in which one symbol is added is not limited.

As another method of allocating additional symbols, there is a method of individually allocating one remaining symbol. As shown in case 3 of FIG. 19, adding a symbol before the first subframe in a frame may be performed by transmitting the control information, such as a preamble or a frame control header (FCH) It is for this reason.

Alternatively, one symbol can be used to transmit additional information, such as sounding, by assigning the symbol after the last subframe in the frame as in case 5. Also, one symbol position is preferably located between the third sub-frame and the fourth sub-frame in consideration of the H-FDD frame structure. However, this is only one example of a preferable position, and there is no limitation in the position of one symbol to be added in the present invention.

Also, as described above, the second type subframe located in the first subframe in the frame may be located in the second subframe in the frame, and the first type subframe may be located in the first subframe in the frame . At this time, as shown in FIG. 19 in the FDD frame structure, the second type subframe located in the first subframe in the frame may be located in the second subframe. By placing the first type subframe consisting of six symbols in the first subframe in the frame, the superframe header structure composed of six previously defined symbols can be used without modification.

As described above, by transmitting and receiving a signal using the TDD frame structure having a CP length of 1/4 Tb at 8.75 MHz and the FDD structure having a commonality with the TTD frame structure proposed in the present invention, Frame can coexist with each other.

Hereinafter, a TDD frame structure having a CP length of 1/4 Tb in the 8.75 MHz band and an FDD frame structure having the commonality with the TDD structure will be described in the IEEE 802.16m system.

The TDD frame structure and the FDD frame structure having a CP length of 1/4 Tb in the 8.75 MHz band according to the present invention have a commonality with a frame structure having different CP lengths as previously defined. In order to coexist with the existing frame structure having a different CP length, the TDD frame is a frame structure in which the switching points from the downlink to the uplink are not overlapped with each other and interference does not occur between them. As shown in Table 1, when the CP length of 1/4 Tb at 8.75 MHz is used, the defined OFDMA parameters are the same as those of the conventional 1/8 Tb CP length and 1/16 Tb CP length . ≪ / RTI > In the case of having a CP length of 1/4 Tb, the symbol period of OFDM is 128 μs, and the number of OFDMA symbols existing in one frame is 39.

It is possible to construct a frame structure having a CP length of 1/4 Tb by using first to third type subframes according to the number of symbols used for defining a subframe in an existing frame structure. In the TDD frame structure, one symbol can be allocated to the TTG / RTG section, and the relative TTG and RTG are 61.6 μs and 74.4 μs when the remaining 38 symbols are allocated to the downlink and uplink regions, respectively. This is smaller than the TTG / RTG in the frame structure having the conventional 1/8 Tb CP length and 1/16 Tb CP length shown in Table 1. Therefore, there is a problem in switching from downlink to uplink.

However, in the present invention, in order to generate an interval similar to the TTG / RTG of a frame having a different CP length as defined in the prior art, two symbols are allocated to the TTG and RTG sections in the TDD frame structure, Can be configured.

20 is a diagram showing an example of a TDD frame structure having a CP length of 1/4 Tb.

Referring to FIG. 20, a TDD frame may be composed of 6 subframes in order to use a first type subframe consisting of 6 symbols, which is a conventional subframe type, and one frame includes 5 first type subframes And one second type sub-frame. That is, when a frame is formed by allocating 38 symbols, one symbol is allocated to one TTG / RTG in one second type subframe among two configured second type subframes, so that the second type subframe is divided into a first type Subframes can be changed, and as a result, a frame structure in which the number of second type subframes is reduced by one compared to a case where a symbol is allocated in advance can be constituted. That is, in the TTD frame structure, one symbol can be allocated as the idle period for the TTG / RTG.

In FIG. 20, when the ratio of the number of downlink subframes to the number of uplink subframes is (5: 1), (4: 2), (3: 3), (2: 4) The total number of symbols allocated to the subframes and the total number of symbols allocated to the uplink subframes may be (31: 6), (25:12), (19:18), (13:24).

One second type subframe in the TDD frame may be located in the downlink or uplink. In this case, since it is preferable that a first type subframe defined in order to transmit a preamble and a superframe header is located in a first subframe of a frame in the case of a downlink, It is appropriate to start from the frame. Accordingly, since the first type subframe having six symbols is located in the first subframe in the frame, the superframe header structure defined by the existing six symbols can be used without changing the subframe structure. The construction of such a frame is merely an example, and the second type sub frame may be located in any sub frame within the frame.

The last subframe of the downlink located in the downlink to uplink transition period is divided into seven subframes including the idle period or one symbol is allocated to the idle period in order to make the time difference necessary for the TTG period in general So that it can be composed of six symbols. However, when the ratio of the number of downlink subframes to the number of uplink subframes is (2: 4), the second type subframe may be located in the last subframe of the downlink. In this case, the last subframe consists of seven symbols. The configuration except for this case can be composed of six symbols irrespective of the ratio of the number of downlink subframes to the number of uplink subframes. Further, one symbol of the second type sub-frame may be further allocated to the TTG to generate a first type sub-frame to form a frame. In FIG. 20, the frame structure of the second type subframe is shown in the second subframe within the frame.

FIG. 21 is a diagram illustrating an example of a TDD frame structure and a corresponding FDD frame structure when the ratio of the number of downlink subframes to the number of uplink subframes is 4: 2 in the TDD frame structure of FIG. 20 .

Referring to FIG. 21, since there is no need to set an additional idle period for the TTG / RTG in the FDD frame structure, a frame can be configured using 39 OFDMA symbols. When an FDD frame is composed of six subframes like a TDD frame, the FDD frame may be composed of three first type subframes and three second type subframes. In this case, in order to transmit a superframe header composed of six symbols, it is preferable that the first type subframe is located in the first subframe of the frame.

In addition, an additional symbol may be allocated after the third subframe or the fourth subframe independently in consideration of the H-FDD frame structure or the midamble in the frame, or one symbol may be placed after the last subframe of the frame, and additional information such as sounding can be transmitted. By doing so, the signal can be transmitted without converting the subframe structure for existing data transmission.

22 is a diagram showing an example of a TDD frame structure having a CP length of 1/4 Tb.

The TDD frame structure of FIG. 22 is a structure in which the second type subframe located in the downlink section in the TDD frame structure shown in FIG. 20 is located on the uplink. At this time, the position of the second type subframe in the uplink is not limited. In this case as well, as shown in FIG. 20, two symbols are allocated to a TTG / RTG period for switching from downlink to uplink. At this time, the last subframe of the downlink may be composed of six symbols by allocating one symbol as an idle period to make a necessary time difference in a TTG period or a subframe consisting of seven symbols. This configuration can be applied regardless of the ratio of the number of downlink subframes to the number of uplink subframes. The other symbol may constitute a frame by constructing a first type subframe including six symbols by assigning one symbol among other second type subframes existing in the frame to the idle period. Accordingly, all downlink subframes may be configured as a first type subframe, and a second type subframe may be allocated to the first subframe of the uplink for use in downlink / uplink separation.

When the ratio of the number of downlink subframes to the number of uplink subframes is (5: 1), (4: 2), (3: 3), (2: 4) The total number of symbols assigned to the corresponding downlink subframes and the total number of symbols allocated to the uplink subframes are (30: 7), (24:13), (18:19), (12:25 ).

23 is a diagram illustrating a TDD frame structure and a corresponding FDD frame structure in a case where the ratio of the number of downlink subframes to the number of uplink subframes in the TDD frame structure shown in FIG. 22 is (4: 2) Fig.

Referring to FIG. 23, a TDD frame structure and an FDD frame structure for a specific ratio of TDD shown in FIG. 22 are shown. In the TDD frame structure shown in FIG. 23, the second type subframe may be located only in the uplink area, and the second type subframe may be located in the first subframe of the uplink subframe. In this case, the downlink / uplink can be divided using the second type sub-frame. In addition, the position of the second type subframe in the uplink is not limited.

In the frame configuration described with reference to FIGS. 20 to 23, when the ratio of the number of downlink subframes to the number of uplink subframes is (6: 0), in the case of the TDD frame, the downlink / There is no need to set the idle interval for switching separately. In this case, the TDD frame structure also has the same configuration as the FDD frame structure. In this case, the first type subframe may be located in the first subframe in the frame to transmit a superframe header composed of six symbols. In this case, the superframe structure and the control channel structure defined by six symbols can be successively used without designing a new subframe structure.

If a frame structure having a CP length of 1/4 Tb according to the present invention is designed, the conventional TTG / RTG section has a different CP length (CP length of 1/8 Tb, CP length of 1/16 Tb) The problem that the TTG / RTG section set in the frame structure can be reduced can be solved.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) Field Programmable Gate Arrays), a processor, a controller, a microcontroller, a microprocessor, or the like.

In the case of an implementation by firmware or software, an embodiment of the present invention can be implemented in the form of a module, a procedure, a function, and the like which perform the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

1 is a diagram showing a basic frame structure in an IEEE 802.16m system,

2 is a diagram illustrating an example of a TDD frame having a downlink and uplink ratio of 5: 3,

3 is a diagram showing an example of a frame structure in the FDD scheme,

FIG. 4 is a diagram illustrating a TDD and FDD frame structure having a CP length corresponding to 1/16 of an effective symbol length Tu; FIG.

5 is a diagram illustrating an example of a symbol structure including a CP (cyclic prefix)

FIGS. 6 to 10 illustrate an example of a TDD frame structure having a CP length of 1/4 Tb that can coexist with a TDD frame structure having a different CP length according to the number of downlink subframes and the number of uplink subframes, respectively The drawings,

11 is a diagram showing an example of an FDD frame structure having a CP length of 1/4 Tb,

12 to 16 are diagrams illustrating an example of a TDD frame structure having a CP length of 1/4 Tb capable of coexisting with a frame structure having a different CP length according to the number of downlink subframes and the number of uplink subframes, respectively ,

17 is a diagram showing an example of an FDD frame structure having a CP length of 1/4 Tb,

18 is a diagram showing an example of a TDD frame structure having a CP length of 1/4 Tb,

19 is a diagram showing an example of an FDD frame structure having a CP length of 1/4 Tb,

20 is a view showing an example of a TDD frame structure having a CP length of 1/4 Tb,

FIG. 21 is a diagram illustrating an example of a TDD frame structure and a corresponding FDD frame structure when the ratio of the number of downlink subframes to the number of uplink subframes is 4: 2 in the TDD frame structure of FIG. 20;

22 is a diagram showing an example of a TDD frame structure having a CP length of 1/4 Tb,

23 is a diagram illustrating an example of a TDD frame structure and a corresponding FDD frame structure when the ratio of the number of downlink subframes to the number of uplink subframes in the TDD frame structure of FIG. 20 is 4: 2 .

Claims (13)

A method for transmitting and receiving signals using a frame structure in a wireless communication system, And transmitting and receiving the signal through a frame having a total number of Orthogonal Frequency Division Multiple Access (OFDMA) symbols of 37 or 39 according to the frame structure, Wherein the frame includes six subframes, wherein the six subframes comprise at least one first type subframe comprising six OFDMA symbols of the total OFDMA symbols and seven OFDMA symbols of the total OFDMA symbols At least one second type of sub-frame, The CP (Cyclic Prefix) length of each OFDMA symbol in the frame is set to 1/4 of the effective symbol length, The channel bandwidth of the frame is set to 8.75 MHz, Wherein the first subframe of the frame is one of the at least one first type subframe having the six OFDMA symbols and the second subframe is one of the at least one second type subframe having the seven OFDMA symbols One, Wherein the length of each of the at least one first type subframe is 0.768 ms and the length of each of the at least one second type subframe is 0.896 ms. The method according to claim 1, Wherein the frame is a Time Division Duplex (TDD) frame or a Frequency Division Duplex (FDD) frame. 3. The method of claim 2, Wherein the TDD frame includes a downlink interval and an uplink interval following the downlink interval, wherein one of the at least one first type subframe is located in a first subframe of the uplink interval. The method of claim 3, In the TDD frame, a transmission transition gap (TTG) is located between the downlink interval and the uplink interval, and a reception transition gap (RTG) is located after the last subframe of the uplink interval. How to. 3. The method of claim 2, Wherein the TDD frame comprises four of the first type subframes and two of the second type subframes. 3. The method of claim 2, Wherein the ratio of the number of downlink subframes to the number of uplink subframes in the TDD frame is one of 5: 1, 4: 2, 3: 3, and 2: 4. 3. The method of claim 2, Wherein the fourth or sixth subframe in the FDD frame is the second type subframe. 3. The method of claim 2, Wherein the FDD frame comprises three of the first type subframes and three of the second type subframes. 3. The method of claim 2, Wherein an idle time is located after the last subframe in the FDD frame. 3. The method of claim 2, wherein the third or fifth subframe of the FDD frame is the first type subframe. An apparatus for transmitting and receiving signals using a frame structure in a wireless communication system, And a transmission / reception module for transmitting / receiving the signal through a frame having a total number of Orthogonal Frequency Division Multiple Access (OFDMA) symbols of 37 or 39 according to the frame structure, Wherein the frame includes six subframes, wherein the six subframes comprise at least one first type subframe comprising six OFDMA symbols of the total OFDMA symbols and seven OFDMA symbols of the total OFDMA symbols At least one second type of sub-frame, The CP (Cyclic Prefix) length of each OFDMA symbol in the frame is set to 1/4 of the effective symbol length, The channel bandwidth of the frame is set to 8.75 MHz, Wherein the first subframe of the frame is one of the at least one first type subframe having the six OFDMA symbols and the second subframe is one of the at least one second type subframe having the seven OFDMA symbols One, Wherein the length of each of the at least one first type subframe is 0.768 ms and the length of each of the at least one second type subframe is 0.896 ms. delete delete

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