KR100521134B1 - Method and apparatus for carrier allocation of an orthogonal frequency division multiple access system - Google Patents

Abstract

A method and apparatus per carrier role in an OFDMA system.

In the device per carrier role of the OFDMA system, the carrier assignment generation unit allocates a carrier based on the base station identifier and the channel assignment number received from the base station, and generates and stores the assigned carrier first index value. The carrier role part stores an output value from the fast Fourier transformed signal of the data received from the base station and a second index value corresponding to the output value. When the fast Fourier transform is completed, the carrier role assignment unit sequentially reads a first index value corresponding to the second index value from the carrier allocation generation unit and performs a carrier role for the output value.

In this way, the per-role carrier method that is changed by the base station identifier and the channel number can be adaptively implemented.

Description

Method and apparatus per carrier role of OPDFMA system {METHOD AND APPARATUS FOR CARRIER ALLOCATION OF AN ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM}

The present invention relates to a method and apparatus per carrier role in an OFDMA system.

For the implementation of wireless broadband multimedia system capable of high-speed reliability and high-capacity service, the OFDM transmission method that can send signals at high data rates in the time division multiple access wireless channel mainly in the millimeter wave band from several GHz to several tens of GHz is spotlighted. Is getting.

OFDM converts the data to be transmitted by inverse fast Fourier transform and divides the used bandwidth into a plurality of subcarriers (subcarriers), and the plurality of transmitted subcarriers are converted to original data by fast Fourier transforming in an OFDM receiver. A frequency multiplexing scheme refers to a frequency multiplexing scheme in which a specific orthogonal condition is applied between subcarrier frequencies so that each subcarrier can be separated at a receiving device despite overlapping spectrum.

In general, in order to improve performance in an OFDMA system, a transmitter performs carrier assignment and then performs inverse fast Fourier transform to transmit transmission data to a receiver through a wireless channel. Therefore, the receiving apparatus of the OFDMA system performs fast Fourier transform on the transmission data received from the transmitting apparatus through a wireless channel, and then performs data per carrier role to restore the data.

In the conventional OFDMA system, a channel role is performed by using a look up table (LUT) method.

FIG. 1 is a block diagram illustrating a transmission and reception apparatus according to a carrier allocation / reassignment method using a lookup table in a conventional OFDMA system.

In FIG. 1, the carrier allocator 20 receives a base station identifier and a channel assignment number by the carrier assignment generation unit 22, allocates a carrier, and inserts data into the assigned carrier through the carrier assignment unit 24. . Then, the transmitting apparatus 10 of the OFDMA system converts the carrier allocated by the carrier allocating apparatus 20 to the inverse fast Fourier transform by the inverse fast fourier transform (ITTF) unit 30 to the receiving apparatus 40 through the wireless channel. Send the data.

When the receiver 40 receives data from the transmitter 10, performs fast Fourier transform by the fast fourier transform (FFT) unit 50, and then performs data per carrier role in the device 60 per carrier role. Receive

The device per carrier role 60 includes a carrier role per part 62 and a carrier role lookup table creator 64.

The lookup table preparation unit 64 per carrier role creates a mapping table according to carrier assignment in consideration of the number of possible cases based on the base station identifier and the channel assignment number received from the transmitter 10 through another radio channel. .

The carrier role part 62 sequentially restores the index of each carrier by playing each carrier by the mapping table.

However, this conventional method per carrier role is very difficult to create a look-up table according to all base station identifiers and channel allocation numbers, so that adaptability according to changes of base station identifiers and channel allocation numbers is reduced, hardware implementation is complicated, and size is large. Is increased. In addition, since the carrier allocation method also varies according to the channel number and the base station identifier BS_ID, there is a problem in that the implementation of the method per carrier role according to the carrier allocation method is very complicated.

The present invention is to solve the above problems, the technical problem to be achieved in the present invention is to improve the adaptability of the method per carrier role of the receiver according to the change of the carrier allocation method of the transmitter in the OFDMA system and the size of the actual receiver To provide a method and apparatus per carrier role of the OFDMA system that can reduce the.

In order to solve this problem, the present invention provides a device that plays a role in a carrier allocated to data transmitted from a base station of an orthogonal frequency division multiplexing access (OFDMA) system and received from a receiving device.

According to an aspect of the present invention, an apparatus for each carrier role of an OFDMA system allocates a carrier based on a base station identifier and a channel assignment number received from the base station, and generates a carrier assignment for generating and storing an assigned carrier first index value. part; And an output value from the fast Fourier transformed signal of the received data and a second index value corresponding to the output value, and stored in the carrier allocation generator corresponding to the second index value when the fast Fourier transform is completed. And a carrier role part performing a role per carrier for the output value based on a first index value.

The carrier role assignment unit may include a first memory configured to store the output value and a second index value corresponding to the output value, and the carrier assignment generation unit may include a second memory configured to store the base station identifier and the channel assignment number; And a third memory configured to store the second index value.

According to the present invention, a method of playing a role assigned to data transmitted from a base station of an orthogonal frequency division multiplexing access (OFDMA) system and received from a receiving apparatus is provided.

According to another aspect of the present invention, a method per carrier role in an OFDMA system includes a) outputting a fast Fourier transform of the transmission data; b) generating a carrier index value according to carrier assignment based on a base station identifier and a channel assignment number received from the base station; And c) storing the output value from step a), and sequentially receiving the carrier index values corresponding to the stored output values and performing a role. In this case, step c) may be performed after the fast Fourier transform is completed.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

First, a carrier allocation / role allocation apparatus according to an embodiment of the present invention will be described in detail with reference to FIG. 2.

2 is a diagram illustrating a carrier allocation / deallocation apparatus and a transmission / reception apparatus according to an embodiment of the present invention.

In the present invention, in order to improve data transmission efficiency, the base station allocates pilot and data to subchannels and transmits them through a common channel or a dedicated channel. The terminal device performs the pilot and data allocated to the subchannels per role to restore and receive the data.

First, as shown in FIG. 2, the transmitting end 200 of the OFDMA system includes a carrier allocation device unit 210 and an IFFT unit 220. The carrier assignment device unit 210 includes a carrier assignment unit 212 and a carrier assignment generation unit 214.

The carrier allocator 212 inserts data into the carrier and transmits the data to the IFFT unit 220 based on the allocation information transmitted from the carrier allocation generator 214.

The carrier assignment generation unit 214 allocates a carrier based on the base station identifier and the channel assignment number and transmits the assignment information to the carrier assignment unit 212.

The IFFT unit 220 converts the data inserted into the carrier by the carrier allocating unit 212 into an inverse fast Fourier transform and converts the frequency domain signal into a signal in the time domain. The converted signal is transmitted to the receiver 300 through a wireless channel.

The receiving end 300 includes an FFT unit 310 and a device unit 320 per carrier role. In addition, the device 320 per carrier role includes a carrier role assignment unit 322 and a carrier assignment generation unit 324.

The FFT unit 310 converts the time domain signal transmitted from the transmitter 200 through the wireless channel into a fast Fourier transform and converts the signal in the frequency domain into a signal in the frequency domain.

The carrier role assigning unit 222 stores an output value and a carrier index value corresponding to the output value in a memory from the signal output from the FFT unit 310. Then, when the fast Fourier transform is completed, the carrier index value generated by the carrier allocation generator 324 is sequentially read to perform data per carrier role for the signal output from the FFT unit 310.

The carrier assignment generation unit 324 performs the same function as the carrier assignment generation unit 214 in the transmitter 200. That is, the carrier assignment generation unit 324 allocates a carrier based on the base station identifier and the channel assignment number and stores an index value according to the carrier assignment in the memory.

At this time, the carrier assignment generation unit 324 receives the base station identifier and the channel assignment number through another radio channel and stores them in a memory. At this time, the base station identifier and the channel assignment number are information previously known through other radio channels.

In this way, by receiving the base station identifier and the channel assignment number as the input and performing carrier assignment, it is possible to easily adapt to the change of the base station identifier and the change of the channel assignment number and to perform the same function as the carrier assignment generation unit 214 of the transmitter 200. The hardware implementation is simple.

The carrier assignment process performed by the transmitter 200 and the receiver 300 will now be described.

In the base station, the subchannel (S = channel assignment number) and the base station identifier ( According to Equation 1, carrier assignment is performed.

here, Is the subchannel Subcarrier The subcarrier index corresponding to

At this time, to be.

And, Is Left Cyclic shifted sequence by Is a sequence of rounding to a positive integer value, Is a positive integer assigned by the MAC to identify a particular base station sector, Is the remainder of X divided by K.

In Equation 1, S = 1, Assuming = 2, carrier assignment

The same method is performed at the receiving end.

Next, the method per carrier role according to the present invention will be described in detail with reference to FIG.

3 is a flowchart of a method per carrier role according to an embodiment of the present invention.

As shown in FIG. 3, the transmitter 200 of the OFDMA system allocates a carrier by the carrier assignment generator 214 based on the base station identifier and the channel assignment number in order to transmit the transmission data (S200) (S210). The carrier assignment generation unit 214 then transmits the assignment information to the carrier assignment unit 212. The carrier allocator 212 inserts data into the carrier and transmits the data to the IFFT unit 220 based on the received allocation information.

The IFFT unit 220 inverses the fast Fourier transform of the carrier into which the transmission data is inserted and converts the signal in the frequency domain into the signal in the time domain (S220). As such, the signal converted into the time domain is transmitted to the receiving end 300 through a wireless channel. Information about the base station identifier and the channel assignment number is also transmitted to the receiver 300 through another channel.

Next, the receiver 300 converts the signal, which is converted into the time domain through the wireless channel, into the fast Fourier transform through the FFT unit 310, and then converts the signal into the signal in the frequency domain and outputs the signal to the carrier role part 222. At this time, the carrier assignment generation unit 214 receives the information on the base station identifier and the channel assignment number transmitted from the transmitter 200 and allocates the carrier in the same manner as the carrier assignment performed in the transmitter 200. That is, the carrier assignment generation unit 214 allocates a carrier based on the base station identifier and the channel assignment number and stores the index value accordingly. Then, when the fast Fourier transform is completed in the FFT unit 310, the carrier role part 222 sequentially reads the index values corresponding to the fast Fourier transformed output values from the carrier allocation generator 214 to index each carrier. Restore it. As described above, the carrier role part 222 receives the data by performing the carrier role (S240) (S250).

The above embodiments are intended to illustrate the present invention, the scope of the present invention is not limited to the embodiments, it can be modified or modified by those skilled in the art within the scope of the invention defined by the appended claims. .

According to the present invention, it is possible to adaptively perform per channel role with respect to the carrier allocation scheme according to the change of the base station identifier and the channel allocation number in the OFDMA system.

In addition, by using the same hardware device according to the carrier assignment in the base station in the receiver, the complexity in hardware implementation can be reduced.

FIG. 1 is a block diagram illustrating a transmission and reception apparatus according to a carrier allocation / reassignment method using a lookup table in a conventional OFDMA system.

2 is a diagram illustrating a carrier allocation / deallocation apparatus and a transmission / reception apparatus according to an embodiment of the present invention.

3 is a flowchart of a method per carrier role according to an embodiment of the present invention.

Claims (5)

An apparatus for playing a role allocated to data transmitted from a base station of an orthogonal frequency division multiplexing access (OFDMA) system and received from a receiving apparatus, the apparatus comprising: A carrier assignment generation unit for allocating a carrier based on a base station identifier and a channel assignment number received from the base station, and generating and storing the assigned carrier first index value; And An output value from the fast Fourier transformed signal of the received data and a second index value corresponding to the output value, and stored in the carrier allocation generator corresponding to the second index value when the fast Fourier transform is completed. 1 per carrier role for performing the per carrier role for the output value based on 1 index value Device per carrier role of the OFDMA system comprising a. The method of claim 1, wherein the carrier role unit, And a first memory configured to store the output value and a second index value corresponding to the output value. The method of claim 1, wherein the carrier allocation generating unit, A second memory for storing the base station identifier and channel allocation number; And A third memory for storing the second index value Device per carrier role of the OFDMA system comprising a. What is claimed is: 1. A method of playing a role allocated to data transmitted from a base station of an orthogonal frequency division multiplexing access (OFDMA) system and received from a receiving device. a) fast Fourier transforming and outputting the transmission data; b) generating a carrier index value according to carrier assignment based on a base station identifier and a channel assignment number received from the base station; And c) storing the output value from step a), and sequentially receiving the carrier index values corresponding to the stored output values and performing a role; Method per carrier role of the OFDMA system comprising a. The method of claim 4, wherein C) is performed after the fast Fourier transform is completed.