KR101336218B1 - Apparatus and method of frame communication in broadband wireless communication system - Google Patents

Abstract

The present invention relates to frame communication in a broadband wireless communication system, wherein, during a first section of a subframe, a process of communication between a base station and a relay station and a transition to a second section of the subframe, the relay station and a first region The base station is used for data transmission, including a process of the terminal communicating and a communication between the base station and the second region terminal in a sector different from the sector in which the relay station is located during the second period of the subframe. Possible radio resources can be increased to improve the overall rate.

Frame composition, relay station, sector

Description

Frame communication apparatus and method in broadband wireless communication system {APPARATUS AND METHOD OF FRAME COMMUNICATION IN BROADBAND WIRELESS COMMUNICATION SYSTEM}

1 is a diagram illustrating a frame structure of a broadband wireless communication system according to an embodiment of the prior art;

2A is a schematic diagram of a cell configuration of a broadband wireless communication system according to the present invention;

2B is a diagram illustrating an interference signal between cells of a broadband wireless communication system according to the present invention;

3 is a diagram illustrating a subframe structure of a broadband wireless communication system according to an embodiment of the present invention;

4 is a diagram illustrating a procedure for a base station to perform frame communication in a broadband wireless communication system according to an embodiment of the present invention; and

5 is a block diagram of a base station block configuration of a broadband wireless communication system according to the present invention;

The present invention relates to a broadband wireless communication system, and more particularly, to a frame communication apparatus and method in a broadband wireless communication system using a relay.

In the 4th Generation (hereinafter, referred to as '4G') communication system, providing users with services having various quality of service (QoS) with a transmission rate of about 100 Mbps. Active research is in progress. In particular, in the current 4G communication system, broadband wireless access such as a wireless local area network (LAN) system and a wireless urban area network (MAN) system Access: Research is being actively conducted to support high-speed services in the form of guaranteeing mobility and quality of service (QoS) in a BWA communication system. In addition, the representative communication system is the Institute of Electrical and Electronics Engineers (IEEE) 802.16 communication system.

The IEEE 802.16 communication system is orthogonal frequency division multiplexing (hereinafter referred to as 'OFDM') / orthogonal frequency division to support a broadband transmission network on a physical channel of the wireless MAN system. A communication system employing an Orthogonal Frequency Division Multiple Access (hereinafter referred to as 'OFDMA') scheme. In the IEEE 802.16 communication system, research is being actively conducted to secure mobility of a terminal and flexibility of a wireless network configuration, and to provide a more efficient service in a wireless environment in which traffic distribution or call demand is changed. As one of the methods, a communication system using a multi-hop relay type data transfer method using a relay station has been considered.

The use of the RS in the broadband wireless communication system causes an increase in the coverage of the base station and an improvement in the throughput. That is, the relay station can be located in a specific area having a poor channel environment to improve the transmission rate. In addition, the relay station can be located near the cell boundary, so that the terminal and the base station outside the coverage of the base station can communicate with each other.

1 shows a frame structure of a broadband wireless communication system according to an embodiment of the prior art.

As shown in FIG. 1, the frame is composed of a downlink subframe 110 and an uplink subframe 120.

The downlink subframe 110 includes a preamble 111, a MAP 113, and a downlink data burst 115. The preamble 111 is an area for transmission / reception synchronization signal of the frame and is also used for channel estimation between the base station and the terminal. The MAP 113 is an area for broadcasting resource allocation information to a terminal and a relay station. The downlink data burst 115 is an area for data transmitted in downlink from the base station and the relay station.

The uplink subframe 120 includes an uplink control information 121 and an uplink data burst 123. The uplink control information 121 is an area for information such as resource allocation request and channel quality. The uplink data burst 121 is an area for data transmitted from the terminal and the relay station to the uplink.

In the frame shown in FIG. 1, the downlink and uplink data burst regions 115 and 123 are divided by time and frequency sections by base stations and terminals, base stations and relay stations, and relay stations and terminal links. That is, each communication link and resources in a cell have a one-to-one correspondence, and multiple communication links cannot use the same resource at the same time. If the same resource is allocated to two different communication links, signals transmitted and received on each communication link may cause severe interference with each other.

As described above, multiple communication links cannot use the same resource due to interference between the communication links in each communication link using a resource in one cell. That is, when the relay station uses the resource of the specific area for communication with the first terminal, the base station cannot use the resource of the specific area for communication with the second terminal. Therefore, the resources used by the relay station in the same cell from the standpoint of the base station is not available, which causes the base station to relatively reduce the resources available for data transmission, resulting in the loss of communication opportunities of the terminals.

Accordingly, an object of the present invention is to provide a frame communication apparatus and method for efficiently using radio resources in a broadband wireless communication system using a relay.

Another object of the present invention is to provide an apparatus and method for performing communication by a base station and a relay station using the same resources in a broadband wireless communication system using a relay.

According to a first aspect of the present invention for achieving the above object, in a cellular system using a relay method, a frame communication method includes a process of performing communication between a base station and a relay station during a first period of a subframe, and the subframe. When the relay station and the first region terminal communicate with each other during the transition to the second interval of, and during the second interval of the subframe, the second region terminal and the base station communicate with each other in a sector different from the sector where the relay station is located. It is characterized by including the process of performing.

According to a second aspect of the present invention for achieving the above object, in a cellular system using a relay method, a frame communication method includes performing communication between a relay station and a first area terminal in a first cell during a first period of a subframe. The communication between the base station and the second area terminal or the base station and the relay station in the second cell adjacent to the first cell, and during the second period of the subframe, the relay station and the first area terminal in the second cell And performing a communication between the base station and the second area terminal or the base station and the relay station in the first cell.

According to a third aspect of the present invention for achieving the above object, a frame communication method of a base station in a cellular system using a relay method, during the first period of the subframe, performing a communication with the relay station, and the subframe When the transition to the second interval of the, it characterized in that it comprises the step of performing communication with the second area terminal in a sector different from the sector located in the relay station communicating with the first area terminal.

According to a fourth aspect of the present invention for achieving the above object, in a cellular system using a relay method, a communication apparatus of a base station performs communication with a base station and a relay station during a first period of a subframe, and a second of the subframe. A scheduler for scheduling resources so that the relay station and the first area terminal communicate with each other during the period, and the second area terminal and the base station communicate with each other in a sector different from the sector in which the relay station is located during the second period of the subframe; And a packet generator for constructing a packet for communication with the relay station or the terminal according to a scheduling result of the scheduler, and a transmitter for transmitting the packet from the packet generator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, the present invention describes a technique for allocating the same resources to a plurality of links in a broadband wireless communication system using a relay. In the following description, the broadband wireless communication system will be described using a time division duplex (hereinafter referred to as TDD) and an orthogonal frequency division multiple access (hereinafter referred to as OFDM) based communication system as an example. The present invention may be equally applicable to a cellular based communication system using a relay scheme.

2 is a schematic diagram illustrating a cell configuration of a broadband wireless communication system according to the present invention.

As shown in FIG. 2A, one cell is divided into two regions based on a distance from the base station 210, and the inside of the boundary line 257 is the base station region 261 and the outer side of the base line 210. Is divided into the relay station area 263. In addition, relay stations 221, 223, and 225 are positioned on the boundary line 257. That is, the terminals 231, 233, and 235 located in the relay station area 263 communicate with each other through the relay stations 211, 223, and 225, and the terminals 241, 243, and 245 located in the base station area 261. Communicates directly with the base station.

In addition, a cell is divided into a plurality of sectors based on the relay stations 221, 223, and 225. That is, as shown in FIG. 2A, the first sector 251 centers on relay station A 221, the second sector 253 centers on relay station B 223, and the third centers on relay station C 225. It is divided into sectors 255. That is, by dividing sectors based on the regularly arranged relay stations 221, 223, and 225, it provides a communication environment in which interference to other sectors due to communication in one sector is minimized. For example, even when the relay station A 221 and the terminal A 231 communicate with each other, and the base station 210 and the terminal E 243 communicate with each other, interference is minimized.

In this case, as shown in FIG. 2B, the terminal 291 in the relay station area 281 transmits a signal at a power sufficient to reach the relay station 293 when performing communication. That is, the terminal 291 located at the cell boundary performs communication with low transmission power. Accordingly, interference to neighbor cells due to a signal transmitted by the terminal 291 in the relay station area 281 is reduced. In particular, the interference of adjacent cells to the base station is significantly reduced.

3 illustrates a subframe structure of a broadband wireless communication system according to an exemplary embodiment of the present invention. Here, the subframe is a basic unit for configuring a frame. When the downlink communication is assumed, the subframe is a downlink subframe, and when the uplink communication is assumed, the subframe is an uplink subframe. Becomes That is, in the case of assuming TDD, one completed frame is formed by connecting a downlink subframe and an uplink subframe.

Referring to FIG. 3A, the subframe is divided into a first section 301 for the RS and a second section 303 for the UE. Here, the first section 301 and the second section 303 are divided into time resources. In addition, when the subframe is a downlink subframe, the base station provides a signal to the relay station in the first section 301, and the second section 303 relays the signal received by the relay station to the terminal. Herein, the resource is divided into time multiplexing as an example, but in another embodiment, the resource may be divided into a frequency division multiplexing or burst concept.

The first section 301 is a section for the base station 210 to communicate with the relay stations 221, 223, and 225 in the cell structure shown in FIG. 2. In this case, the base station 210 may communicate resources by dividing the resources not only to the relay station but also to the terminals 241, 243, and 245 in the base station area 263.

The second section 303 is a section for the base station 210 to communicate with the terminals 241, 243, and 245 located in the base station area 261 in the cell structure shown in FIG. 2. In addition, the relay stations 221, 223, and 225 communicate with the terminals 231, 233, and 235 located in the relay station area 261. That is, the base station 210 and the relay stations 221, 223, and 235 simultaneously communicate with terminals that are dependent on themselves by using the same resources. In this case, the terminals of the base station area 263 and the relay station area 261 that simultaneously perform the same resource communication should be terminals located in different sectors to prevent mutual interference.

The embodiment described in (a) of FIG. 3 has described a subframe structure for one base station. As another embodiment, when a plurality of adjacent base stations are considered, only one relay station and a terminal link communicate with each other in the same time interval among the subframes of the plurality of neighbor base stations, as shown in FIG. You can configure subframes to do this. That is, by configuring a frame such that only one of the terminals located at the cell boundary performs communication in the same time interval, interference between cells can be greatly reduced.

4 illustrates a procedure for a base station to perform frame communication in a broadband wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 4, in step 401, the base station determines whether the frame is the first section of the frame for communication with the relay station.

If it is the first period of the frame, the base station proceeds to step 403 to perform communication with the relay stations. At this time, the radio resources for the relay station may be divided and communicated with the terminal during the first period of the frame.

In step 405, the base station determines whether the RS is in the second section of the frame in which the RS communicates with the terminal.

If it is the second period of the frame, the base station proceeds to step 407 to communicate with a terminal of a sector different from the sector in which the relay station is located. For example, in the cell configuration as shown in FIG. 2, when it is confirmed that the relay station A 221 of the first sector 251 is performing communication with the terminal A 231, the base station is assigned to the second station. Communication with the terminal E 243 of the sector 253 or the terminal F 245 of the third sector 255 is performed.

5 is a block diagram of a base station of the broadband wireless communication system according to the present invention.

As shown in FIG. 5, the base station includes a scheduler 501, a MAP generator 503, a terminal data buffer 505, a relay station data buffer 507, a switch 509, a burst generator 511, and a multiplexer. It includes a talker 513, a modulator and encoder 515, a resource mapper 517, an OFDM modulator 519, a digital analog converter (hereinafter referred to as a DAC), and an RF processor 523.

The scheduler 501 performs resource scheduling for communicating with relay stations and terminals. In addition, the generation of data bursts to be transmitted to the RSs and the UEs is controlled according to the scheduling result. In particular, according to the present invention, the resource is scheduled so that the RS can communicate with the terminal without interference during the communication period with the terminal. In other words, the sector in which the relay station to which the resource is allocated is located is identified during the interval, and the resource is scheduled to communicate with a terminal in a sector different from the sector in which the relay station is located using the same resource during the same interval.

The MAP generator 503 receives resource allocation information from the scheduler 501 and generates a MAP message for broadcasting to the relay station and terminals.

The terminal data buffer 505 temporarily stores data to be transmitted to the terminals. The relay station data buffer 507 temporarily stores data to be transmitted to the relay stations. The switch 509 switches the data from the terminal data buffer 505 and the relay station data buffer 507 to the burst generator 511 under the control of the scheduler 501.

The burst generator 511 generates a data burst for transmission to the terminal or relay station using the packet provided from the terminal data buffer 505 or the relay station data buffer 507.

The multiplexer 513 multiplexes the MAP message provided from the MAP generator 503 and the data burst provided from the burst generator 511. The modulator and encoder 515 encodes the multiplexed data provided from the multiplexer 513 at a corresponding code rate and modulates the modulated data in a corresponding modulation scheme.

The resource mapper 517 maps data provided from the modulator and encoder 515 to a corresponding subcarrier resource. The OFDM modulator 519 converts the frequency domain signal mapped on the frequency provided from the resource mapper 517 into an inverse fourier transform (IFFT) operation and converts it into a time domain signal.

The DAC 521 converts a digital signal provided from the OFDM modulator 519 into an analog signal. The RF processor 523 converts the baseband signal provided from the DAC 521 into a corresponding carrier frequency band and outputs it through an antenna.

Referring to the operation based on the configuration of FIG. 5, the scheduler 501 controls the switch 509 to output data from the relay station data buffer 507 in the first section according to a scheduling result. In addition, when transitioning to the second section, the scheduler 501 checks a scheduling result and outputs a packet of a terminal located in a sector which does not interfere with the relay station communicating in the second section from the terminal data buffer 505. The switch 509 to be controlled. As described above, the present invention proposes a frame communication that can efficiently use radio resources by constructing a frame so that the base station can communicate with the terminal even in a period where the relay station is communicating.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, in a broadband wireless communication system using a relay, the base station and the relay station simultaneously communicate with the terminal using the same resources, thereby increasing the radio resources available for the base station to transmit and receive data, thereby improving the overall transmission rate.

Claims (23)

In the frame communication method in a cellular system using a relay method, During the first period of the subframe, the base station and the relay station performing communication; When the relay station transitions to the second section of the subframe, the relay station and the first region terminal perform communication; And performing a communication between a base station and a second area terminal in a sector different from a sector in which the relay station is located during the second period of the subframe. The method according to claim 1, And a first section and a second section of the subframe are divided by time division multiplexing. The method according to claim 1, The first region and the second region, characterized in that divided based on the distance from the base station. The method according to claim 1, The first area terminal is a terminal located more than a predetermined distance from the base station, And the second area terminal is a terminal located within a predetermined distance from the base station. 5. The method of claim 4, And the predetermined distance is a distance between the base station and the relay station. In the frame communication method in a cellular system using a relay method, During the first period of the subframe, the relay station and the first area terminal communicate in the first cell, and the base station and the second area terminal or the base station and the relay station communicate in the second cell adjacent to the first cell and, During the second period of the subframe, the relay station and the first region terminal communicate with each other in the second cell, and the base station and the second region terminal or the base station and the relay station communicate with each other in the first cell. How to feature. The method according to claim 6, The first interval and the second interval, characterized in that divided into time division multiplexing. The method according to claim 6, The first region and the second region, characterized in that divided based on the distance from the base station. The method according to claim 6, The first area terminal is a terminal located more than a predetermined distance from the base station, And the second area terminal is a terminal located within a predetermined distance from the base station. 10. The method of claim 9, The predetermined distance is a distance between the base station and the relay station in one cell. In a frame communication method of a base station in a cellular system using a relay method, During the first period of the subframe, communicating with the relay station; And transitioning to the second section of the subframe, performing communication with a second region terminal in a sector different from a relay station located sector communicating with the first region terminal. 12. The method of claim 11, And a first section and a second section of the subframe are divided by time division multiplexing. 12. The method of claim 11, The first region and the second region, characterized in that divided based on the distance from the base station. 12. The method of claim 11, The first area terminal is a terminal located more than a predetermined distance from the base station, And the second area terminal is a terminal located within a predetermined distance from the base station. 15. The method of claim 14, And the predetermined distance is a distance between the base station and the relay station. 12. The method of claim 11, Communication during the first section or the second section, And allocating resources to respective terminals and relay stations using one of time division, frequency division, and burst division. In a communication system of a base station in a cellular system using a relay method, The base station and the relay station communicate with each other during the first period of the subframe, and the relay station and the first area terminal communicate with each other during the second period of the subframe, and different from the sector in which the relay station is located during the second period of the subframe. A scheduler that schedules resources so that a second area terminal in the sector and the base station communicate; A packet generator configured to configure a packet for communication with the relay station or the terminal according to a scheduling result of the scheduler; And a transmitter for transmitting a packet from the packet generator. 18. The method of claim 17, And a first section and a second section of the subframe are divided into time resources. 18. The method of claim 17, And the first area and the second area are separated by a distance from a base station in a cell. 18. The method of claim 17, The first area terminal is a terminal located more than a predetermined distance from the base station, And the second area terminal is a terminal located within a predetermined distance from the base station. 21. The method of claim 20, And the predetermined distance is a distance between the base station and the relay station. 18. The method of claim 17, The transmitter may further comprise: A modulation and encoder for encoding and modulating data in a corresponding manner; A resource mapper for mapping data from the modulation and encoder to a predetermined resource according to the control of the scheduler; An OFDM modulator for performing Orthogonal Frequency Division Multiplexing (OFDM) modulation on resource mapped data from the resource mapper; And an RF processor converting the data from the OFDM modulator into a radio frequency (RF) band signal and transmitting the converted signal. 18. The method of claim 17, The scheduler comprising: And allocating resources to each of the terminals and each of the relay stations during one of the first and second periods using one of time division, frequency division, and burst division.

Images