KR20090070737A - Apparatus and method for constructing a frame in a communication system - Google Patents

Abstract

An apparatus and a method for constructing a frame in a communication system are provided to enable a mobile terminal to smoothly switch an operation of the mobile terminal while maximally maintaining a frame structure of an H-FDD(Half Duplex-Frequency Division Duplex) mode. A base station separates the first and second sub frames as much as a section to which the first transmit/receive transition gap and the first transmit/receive transition gap are added and separates the third and fourth frames as much as one OFDM(Orthogonal Frequency Division Multiplexing) access symbol section, thereby configuring a frame. The first sub frame comprises downlink data of mobile terminals included in the first group in the first frequency band. The second sub frame comprises the downlink data of the mobile terminals included in the second group.

Description

Apparatus and method for frame construction in a communication system {APPARATUS AND METHOD FOR CONSTRUCTING A FRAME IN A COMMUNICATION SYSTEM}

The present invention relates to a communication system, and more particularly, to an apparatus and method for constructing a frame in a communication system.

In a general communication system, a transceiver, for example, a base station (BS) or a mobile station (MS) uses a frame structure for mutual data exchange. The communication system uses a frame structure for data transmission between the base station and the mobile terminal, so that the base station efficiently allocates resources of each frame to the mobile terminals.

Then, when the base station transmits and receives data using the frame with the mobile terminal in the communication system will be described with reference to Figure 1 below.

1 is a diagram illustrating a frame structure of a general communication system.

Referring to FIG. 1, it is assumed that the communication system uses a time division duplex (TDD) scheme as an example. An example of a frame transmitted and received between a base station and a mobile terminal of the communication system will be described.

One frame includes a downlink section and an uplink section. The downlink period includes a preamble, a map, and a downlink data burst, and the uplink frame period includes an uplink data burst.

The preamble includes information for performing synchronization acquisition.

The map is information that can be restored from a frame control header or the like included in the frame, and includes data extraction information such as the position and size of a data burst in the frame and various information for providing a service to a receiver. Accordingly, the receiver receiving the frame extracts a data burst received by the mobile terminal in the frame by analyzing the map information.

The downlink data burst is downlink data transmitted from the base station to the mobile terminal, and the uplink data burst is uplink data transmitted from the mobile terminal to the base station.

In addition, the frame is referred to as a transmit / receive transition gap (TTG) and a transmit / receive transition gap (RTG). It is included). Here, the TTG and the RTG serve as a guard interval when transmitting and receiving data through the frame.

In FIG. 1, two frames are shown. For example, a length of one frame section has a value of 2 msec to 20 msec. Here, it is assumed that 5 msec (downlink section + uplink section + TTG + RTG). For example, it is assumed that the sum of the A symbols and the B symbols shown in the figure is 47 symbols (A symbols + B symbols).

FIG. 1 illustrates an example in which the base station and the mobile terminal use a time division duplex (TDD) method for transmitting and receiving data. The base station and the mobile terminal using the TDD scheme divide the same frequency band in the time domain for uplink and downlink.

However, when the base station and the mobile station use a frequency division duplex (FDD) scheme, frequency domains are divided and used. Thus, when the frame structure used in the time division duplex scheme is used, waste in terms of resource efficiency Severe. For example, consider a frequency division duplex communication system. In the frequency division duplex communication system, a base station and a mobile terminal can transmit and receive data using at least two frequency bands.

The frequency division duplex communication system operates in a full duplex frequency duplex, that is, full duplex-frequency division duplex (F-FDD) and half frequency duplex. It may be classified into a duplex method, that is, a half duplex-frequency division duplex method (hereinafter, referred to as H-FDD).

In the F-FDD scheme, a mobile terminal receives a signal from a base station through a first frequency band, and the mobile terminal transmits a signal to the base station through a second frequency band. However, the H-FDD scheme cannot transmit a signal to the base station through the second frequency band while the mobile terminal receives a signal from the base station through the first frequency band.

Basically, a base station having an F-FDD function is not only an F-FDD mobile terminal but also an H-FDD base station supporting an F-FDD mobile terminal and an H-FDD mobile terminal simultaneously or an H-FDD system. In case of supporting only the mobile terminal, the frame structure should be designed in accordance with H-FDD type mobile terminal.

Therefore, in the communication system using the H-FDD scheme, the mobile terminal receives a signal through a first frequency band and then a guard period between a downlink period and an uplink period so that the mobile station can transmit a signal through a second frequency band. That is, the operation switching interval should be set.

In this case, since the frequency band in which the mobile terminal receives the signal and the frequency band in which the signal is transmitted are different from each other according to the H-FDD scheme, the communication system performs the operation switching period in the same manner as in the TDD scheme. It cannot be set. Accordingly, there is a need for a frame structure including an interval for switching the operation of a mobile terminal in a communication system using the H-FDD scheme.

Accordingly, an object of the present invention is to provide an apparatus and method for constructing a frame in a communication system.

Another object of the present invention is to provide an apparatus and method for constructing a frame in a communication system using a half-frequency split duplex scheme.

Another object of the present invention is to provide an apparatus and method for configuring a frame in which an operation switching interval of a communication system using a half-frequency split duplex scheme is set.

A method of the present invention for achieving the above object relates to a frame configuration method of a base station communicating with a mobile terminal of the half-frequency split duplex method in a communication system. In the first frequency band, the base station includes a first subframe including downlink data of mobile terminals included in a first group and a second subframe including downlink data of mobile terminals included in a second group. A third subframe including uplink data of mobile terminals included in the second group in a second frequency band, spaced apart by a period in which a reception transition gap and a first number / transmit transition gap are added, and a movement included in the first group The fourth subframe including the uplink data of the terminals are spaced by one orthogonal frequency division multiple access symbol interval.

An apparatus of the present invention for achieving the above object relates to a frame configuration device for communicating with a mobile terminal of the half-frequency split duplex method in a communication system. The frame forming apparatus may include a first subframe including downlink data of mobile terminals included in a first group and a second subframe including downlink data of mobile terminals included in a second group in a first frequency band. A third sub-frame including uplink data of mobile terminals included in the second group in the second frequency band and spaced apart by the interval where the transmit / receive transition gap and the first receive / transmit transition gap are added, and included in the first group The fourth subframe including the uplink data of the mobile terminals includes a base station constituting the frame spaced apart by one orthogonal frequency division multiple access symbol interval.

The present invention, when communicating with the mobile terminal of the half-duplex-frequency division duplex (H-FDD) scheme in a communication system, one or more of symbols included in the time division duplex frame configuration By additionally using symbols as the operation switching interval, the operation switching interval of the H-FDD scheme is set, and thus the mobile terminal can smoothly switch the operation while maintaining the frame structure of the time division duplex scheme as much as possible.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

The present invention provides a frame configuration apparatus and method in a communication system. In particular, the present invention is a full duplex-Frequency Division Duplex (hereinafter referred to as 'F-FDD') base station is a half duplex-Frequency Division Duplex (hereinafter referred to as 'H-FDD') Provided is a frame configuration apparatus and method for supporting a mobile terminal of the FDD 'method).

It is assumed that a transceiver of the communication system according to the present invention is a base station (BS) or a mobile station (Mobile Station). The base station and the mobile terminal may use the frequency division duplex scheme, and the frequency division duplex scheme may communicate with each other using the F-FDD and H-FDD schemes. In the present invention, it will be described on the assumption that the mobile terminal communicates with the base station using the half-frequency duplex scheme. Therefore, it is assumed that the mobile terminal of the present invention performs only one operation of data transmission or reception at a specific time in half-duplex operation.

In a communication system using a conventional time division duplex (hereinafter, referred to as 'TDD') scheme, a transmit / receive transition gap (hereinafter referred to as 'TTG') and a receive transition gap ( Receive / transmit Transition Gap, hereinafter referred to as 'RTG').

For example, when the bandwidth is 10M, the TDD system transmits a maximum mobile terminal transmit / receive gap (Subscriber Station Transmit / receive Transition Gap, hereinafter referred to as 'SSTTG') for switching the operation of the mobile terminal. The Subscriber Station Receive / Transmit Transition Gap (SSRTG) considers 50 us. The TTG is set to a value obtained by adding the SSRTG and a round trip delay (hereinafter, referred to as 'RTD'), and the RTG is set to a value obtained by subtracting the RTD from the SSTTG.

Meanwhile, in the H-FDD system, the SSTTG and SSRTG values should be set to values of about 100us larger than the current 50us. In the following description, TTG and RTG of the TDD system will be referred to as TTG 'and RTG', respectively.

In the TDD system, for example, when the bandwidth is 10M, one frame includes 47 Orthogonal Frequency Division Multiplex Access (OFDMA) symbols and one TTG (TDD). It contains one RTG (TDD). At this time, one OFDMA symbol is composed of a size of 102.87us, for example. In this case, the F-FDD system requires 100us more than SSTTG and SSRTG of the TTD system in order to switch the operation of the H-FDD mobile terminal. Accordingly, the F-FDD system extends the TTG (TDD) section and the RTG (TDD) section by using one OFDMA symbol among the 47 OFDMA symbols of the TDD system. For example, as shown in Equation 1 below. It can be used as TTG and RTG for the H-FDD type UE.

TTG = TTG '+ (1 OFDMA symbol / 2)

RTG = RTG '+ (1 OFDMA symbol / 2)

The TTG represents a TTG of a mobile terminal operating in an H-FDD scheme, the RTG represents an RTG of a mobile terminal operating in an H-FDD scheme, and the TTG ′ represents a TTG of a mobile terminal operating in a TDD scheme. The RTG ′ denotes an RTG of a mobile terminal operating in a TDD scheme.

In Equation 1, TTG and RTG of the mobile terminal operating in the H-FDD scheme are set to a value in which half (1/2) of one OFDMA symbol is added to TTG 'and RTG' in the TDD communication system. This is described as an example. Therefore, the TTG and the RTG may be configured by using at least one OFDMA symbol for the TTG 'and the RTG'.

A frame structure used for communication with a base station by a mobile terminal operating in the H-FDD scheme will be described with reference to FIG. 2 below.

2 is a diagram illustrating a frame structure of an H-FDD mobile terminal according to an embodiment of the present invention.

Referring to FIG. 2, for example, two frequency bands are illustrated. A first frequency band is a frequency band used for downlink data transmission between a base station and a mobile terminal operating in the H-FDD scheme, and a second frequency band. It is assumed that the band is a frequency band used for uplink data transmission between a base station and a mobile terminal operating in the H-FDD scheme.

On the other hand, in the present invention, the mobile terminal operating in the H-FDD scheme in the cell of the base station is divided into two groups for efficient use of the frequency band. When the first group of mobile terminals transmits data, the second group of mobile terminals receives data. When the first group of mobile terminals receives data, the second group of mobile terminals receive data. Receive.

The base station may classify the H-FDD-type mobile terminals into groups according to cell load characteristics, mobile terminal positions, the number of mobile terminals in each group, and cell load characteristics. For example, the base station can notify the changed group information to the mobile terminal, each mobile terminal determines the mobile terminal group to which it belongs through the group information received from the base station, and transmits and receives data corresponding to the determined mobile terminal group Can be done.

Here, since the base station divides the mobile terminals into groups, the detailed description thereof will be omitted.

The first frequency band includes a preamble, a common map, a first group map, a first group downlink data burst, a second group map, and a second group map. Group downlink data bursts.

The preamble includes information for performing synchronization acquisition.

The common map is information that can be restored from a frame control header or the like included in the frame. For example, the common map includes map extraction information such as the position and size of the first group map and the second group map. Accordingly, the mobile terminals receiving the map may receive a first group map or a second group map corresponding to each group of the mobile terminals.

The first group map includes data extraction information such as the location and size of a data burst of the first group of mobile terminals in the frame and various information for providing a service to the first group of mobile terminals. Accordingly, the mobile terminal receiving the first group map extracts a data burst received by the mobile terminal of the first group in the frame by analyzing the first group map information.

The second group map includes data extraction information such as the location and size of data bursts of the second group of mobile terminals in the frame and various information for providing a service to the second group of mobile terminals. Accordingly, the mobile terminal receiving the second group map extracts a data burst received by the mobile terminal of the second group in the frame by analyzing the second group map information.

The first group downlink data burst is downlink data transmitted by the base station to the mobile station of the first group, and the second group downlink data burst is downlink data transmitted by the base station to the mobile station of the second group.

The second frequency band includes a first group uplink data burst and a second group uplink data burst.

The first group uplink data burst is uplink data transmitted by a mobile station of a first group to a base station, and the second group uplink data burst is uplink data transmitted by a mobile station of a second group to a base station. .

The first frequency band includes 47 OFDMA symbols, TTG ', RTG'. And a first subframe including the preamble, the common map, the first group map, and the first group downlink data burst, and a second subframe including the second group map and the second group downlink data burst. A gap having a size of TTG 'and RTG' is added between the first subframe and the second subframe. The TTG 'and the RTG' mean TTG and RTG defined in a TDD communication system.

The subframe means a set of OFDMA symbols within one frame, and the subframe is divided by the TTG, RTG, TTG ', RTG', and the like.

The second frequency band includes a third subframe including a second group uplink data burst and a fourth subframe including the first group uplink data burst. A gap of 1 OFDM symbol size is inserted between the third subframe and the fourth subframe.

The TTG of Equation 1 is inserted before the third subframe, and the TTG is inserted at the end of the common map of the first frequency band. In addition, the RTG of Equation 1 is inserted after the fourth subframe, and the RTG is inserted in the first frequency band before the start of the next frame, that is, before the start of the preamble of the next frame.

Therefore, the base station of the present invention can communicate with H-FDD-type mobile terminals divided into at least two groups, and transmits the first subframe in a first frequency band and adds the TTG 'and the RTG'. The second subframe is transmitted with a size gap. In addition, the third subframe is transmitted in the second frequency band, and the fourth subframe is transmitted with a gap of one OFDMA symbol size.

Herein, a time point corresponding to a gap of the first OFDMA symbol size, that is, half of the first OFDMA symbol period, is set to be the same as the time point at which TTG 'ends after the first subframe transmission.

Using the frame structure, the base station in the first frequency band and the second frequency band can transmit and receive data to the mobile terminal using the H-FDD scheme with the TTG and RTG as in Equation (1).

3 and 4 are diagrams for explaining a frame structure operated by a base station according to an embodiment of the present invention to support an H-FDD type terminal. For example, a 5 ms frame consists of 46 OFDMA symbols, TTG, and RTG. Since one OFDMA symbol is used to increase the TTG and RTG values to support the H-FDD scheme, the number of available symbols is reduced from 47 to 46.

Next, a frame received by the first group of mobile terminals using the H-FDD scheme will be described with reference to FIG. 3.

3 is a diagram illustrating a frame received by a first group of mobile terminals using an H-FDD scheme according to an embodiment of the present invention.

Referring to FIG. 3, the mobile station of the first group receives the preamble and the common map from the base station through the first frequency band.

The mobile terminal receives a first group map corresponding to the first group of mobile terminals in a first frequency band through the common map. The mobile terminal receives downlink data bursts assigned to the mobile terminal through the first group map.

The mobile terminal receives a downlink data burst from the base station through a first frequency band, and transmits an uplink data burst to the base station through a second frequency band.

The mobile terminal includes an operation switching period, that is, TTG, before the downlink data burst reception time and the uplink data burst transmission time, and includes an operation switching period, that is, RTG, after the uplink data burst transmission time. do.

Accordingly, the mobile terminal may include an operation switching section required for operation switching of the transmission / reception mode according to the use of the H-FDD scheme through the frame structure proposed in the present invention.

Next, a frame received by the second group of mobile terminals using the H-FDD scheme will be described with reference to FIG. 4.

4 is a diagram illustrating a frame received by a second group of mobile terminals using the H-FDD scheme according to an embodiment of the present invention.

Referring to FIG. 4, the second group of mobile terminals receives a preamble and a common map from a base station through a first frequency band.

After receiving the common map, the mobile terminal transmits an uplink data burst to the base station through the second frequency band.

The mobile terminal transmits the uplink data burst and receives a first group map corresponding to the first group of mobile terminals in a first frequency band through the common map. The mobile terminal receives downlink data bursts assigned to the mobile terminal through the first group map.

The mobile terminal transmits an uplink data burst to the base station through a second frequency band, and receives a first group map and a downlink data burst from the base station through a first frequency band.

The mobile terminal includes an operation switching period before the common map reception completion time and the uplink data transmission time, that is, a TTG, and includes an operation switching period before the uplink data burst transmission completion time and the second group map reception time. That includes RTG.

Accordingly, the mobile terminal may include an operation switching section required for operation switching of the transmission / reception mode according to the use of the H-FDD scheme through the frame structure proposed in the present invention.

Therefore, one frame proposed in the present invention has a size including 47 OFDMA symbols, TTG ', RTG'.

The base station includes, for example, a scheduler, a map generator, a frame generator, a transmitter, and a receiver.

The scheduler classifies data for each terminal group and generates resource allocation information of the classified data. The map generator generates a common map and each group map by using the data resource allocation information. The frame generation unit generates a frame using the classified data and a map, and the transmission / reception unit transmits / receives data with the corresponding mobile terminal through a frame including a gap between each subframe and an operation switching section as shown in FIG. 2. Can be.

The frame generator is configured based on two frequency bands, wherein the first frequency band generates a first sub frame period and a second sub frame period, and the second frequency band includes a third sub frame period and a fourth sub period. Create a frame section. The base station transmits the first subframe and the second subframe to the corresponding mobile terminals through the generated subframe period, and receives the third subframe and the fourth subframe from the mobile terminals.

The frame generator is spaced apart by a period where TTG 'and RTG' are added between the first frame and the second frame, and the third subframe and the fourth subframe are spaced apart by one OFDMA symbol.

A start point of a third subframe is set at a point spaced apart by TTG after a common map transmission point of the first subframe, and a start point of a next frame is set at a point spaced apart by RTG after the point of reception of the fourth subframe. The base station transmits a preamble of a next frame through a first frequency band when the RTG ends.

At this time, the mobile terminal operates in the H-FDD scheme and can communicate through the frame structure shown in FIG. Here, the mobile terminal transmits and receives data with the base station through a frame corresponding to the group including the mobile terminal.

In order to support the H-FDD mobile terminal, the communication system including the H-FDD-type mobile terminal, for example, has extended TTG 'and RTG' of the existing TDD communication system by using one OFDMA symbol. The H-FDD mobile terminal maintains the TTG 'and RTG' values while maintaining the structure of the existing TDD frame to the maximum in the transmission / reception mode switching according to the frequency band change according to the data transmission and reception through the TTG and the RTG proposed in the present invention. Can be extended.

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 the equivalents of the claims.

1 illustrates a frame structure of a general communication system;

2 is a diagram illustrating a frame structure of an H-FDD mobile terminal according to an embodiment of the present invention;

3 is a diagram illustrating a frame received by a first group of mobile terminals using an H-FDD scheme according to an embodiment of the present invention;

4 is a diagram illustrating a frame received by a second group of mobile terminals using the H-FDD scheme according to an embodiment of the present invention.

Claims (14)

A frame configuration method of a base station communicating with a mobile terminal of a half-frequency split duplex method in a communication system, A first transmission / reception transition gap includes a first subframe including downlink data of mobile terminals included in a first group and a second subframe including downlink data of mobile terminals included in a second group in a first frequency band. Spaced apart by the interval where the first number / transmit transition gap is added; In the second frequency band, a third subframe including uplink data of mobile terminals included in the second group and a fourth subframe including uplink data of mobile terminals included in the first group include one orthogonal frequency division multiplexing. And a process of spaced apart by an access symbol interval. The method of claim 1, The mobile terminal included in the first group is a frame configuration method, characterized in that the data transmission and reception operation is in conflict with the mobile terminal included in the second group. The method of claim 1, The first subframe includes a preamble, a common map, a first group map, and a first group downlink data burst, the second subframe includes a second group map and a second group downlink data burst, And wherein the third subframe includes a second group uplink data burst, and the fourth subframe includes a first group uplink data burst. The method of claim 3, wherein Setting a start time point of a third subframe period by spaced apart by a second transmit / receive transition gap after completion of the common map transmission of the first subframe; And setting a start time point of a next frame spaced apart by a second number / transmit transition gap after an end time point of the fourth sub frame period. The method of claim 4, wherein The first transmit / receive transition gap is a transmit / receive transition gap of a time division duplex communication system, and the first transmit / receive transition gap is a receive / transmit transition gap of a time division duplex communication system. The reception transition gap is a gap in which 1/2 orthogonal frequency division multiple access symbols are added to the first transmission / reception transition gap, and the second reception / transmission transition gap is 1 / second to the first reception / transmission transition gap. And a gap in which two orthogonal frequency division multiple access symbols are added. The method of claim 4, wherein And a half time point of the one orthogonal frequency division multiple access symbol is an end time point of the first transmission / reception transition gap after the first subframe. The method of claim 4, wherein The size of each frame of the first frequency band and the second frequency band is a size including 46 orthogonal frequency division multiple access symbols, a second transmit / receive transition gap, and a second transmit / receive transition gap. How frames are organized. A frame configuration apparatus for communicating with a half-frequency split duplex mobile terminal in a communication system, A first transmission / reception transition gap includes a first subframe including downlink data of mobile terminals included in a first group and a second subframe including downlink data of mobile terminals included in a second group in a first frequency band. And a third sub-frame including uplink data of mobile terminals included in the second group in the second frequency band and spaced apart by a period where the first number / transmit transition gap is added and uplinks of the mobile terminals included in the first group. And a fourth subframe including link data comprises a base station configured to form a frame by one orthogonal frequency division multiple access symbol interval. The method of claim 8, The mobile terminal included in the first group is a frame configuration device, characterized in that the data transmission and reception operation is in conflict with the mobile terminal included in the second group. The method of claim 8, The first subframe includes a preamble, a common map, a first group map, and a first group downlink data burst, and the second subframe includes a second group map and a second group downlink data burst. And the third subframe includes a second group uplink data burst, and the fourth subframe includes a first group uplink data burst. The method of claim 10, The base station sets a start time of a third subframe period after being spaced apart by a second transmit / receive transition gap after the completion of the common map transmission of the first subframe, and after the end time of the fourth subframe period. And a start time point of the next frame spaced apart by two male / transmit transition gaps. The method of claim 11, The first transmit / receive transition gap is a transmit / receive transition gap of a time division duplex communication system, and the first transmit / receive transition gap is a receive / transmit transition gap of a time division duplex communication system, and the second A transmit / receive transition gap is a gap in which 1/2 orthogonal frequency division multiple access symbols are added to the first transmit / receive transition gap, and the second transmit / receive transition gap is 1 in the first receive / transmit transition gap. And / or two orthogonal frequency division multiple access symbols. The method of claim 12, And a half time point of the one orthogonal frequency division multiple access symbol is an end time point of the first transmission / reception transition gap after the first subframe. The method of claim 12, The size of each frame of the first frequency band and the second frequency band is a size including 46 orthogonal frequency division multiple access symbols, a second transmit / receive transition gap, and a second transmit / receive transition gap. Frame construction device.

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