KR100490324B1 - Method for transmission in wireless cellular network system and transmission system - Google Patents

Abstract

The present invention relates to an apparatus and method for transmitting data in a wireless cellular communication network system. The present invention relates to a wireless cellular communication network system in which a base station is installed in units of cells in a predetermined area and relays data in an orthogonal frequency division multiplexing scheme using the base station. A transmission apparatus used, comprising: encoding means for encoding data to be transmitted; Subcarrier mapping means for mapping the encoded signal and subcarriers for transmitting the encoded signal; And multicarrier modulation means for converting the signal in the mapped frequency domain into a signal in the time domain, wherein the subcarrier mapping means punctures some of the subcarriers used in the wireless cellular communication network system and punctures the subcarrier mapping means. The present invention relates to a transmission apparatus used in a wireless cellular communication network system, and a method using the same, which is different from a subcarrier punctured in a neighboring cell and a corresponding cell in which the punctured subcarrier is used.

According to the present invention, there is an advantage in that inter-cell interference can be prevented while using frequency efficiently.

Description

Method for transmission in wireless cellular network system and transmission system

The present invention relates to an apparatus and method for transmitting data in a wireless cellular network system.

Since a wireless communication network system that wirelessly relays data transmission using a notebook computer, PDA (Personal Digital Assistants), etc., cannot relay all regions to which the wireless communication network system is applied using a single relay device. As described above, a cellular method is used to divide a predetermined range of regions into units called 'cells' and to install a base station (Access Point) for each cell to relay data transmission on a cell basis.

Since each base station responsible for communication of each cell transmits a separate signal, even if one wireless terminal is located in an area that can simultaneously receive signals from two base stations using the same frequency band, Even if the strength of the signal received from the base station is different, the signals received from each base station interferes with each other, the wireless terminal has a problem that eventually can not properly decode the signal received from any base station.

The conventional wireless cellular communication network system has attempted to solve the above problems by using different frequency bands for each cell.

However, since a frequency band allocated for a wireless communication network system is generally not so wide, the above method of dividing such a narrow frequency band has a problem of limiting the amount of data that can be transmitted through one base station. there was.

Orthogonal Frequency Division Multiplexing (OFDM) has been introduced to transmit more data using the same frequency band. Orthogonal frequency division multiplexing is a frequency multiplexing scheme in which data is distributed and transmitted over multiple subcarriers. A frequency multiplexing scheme allows a specific orthogonal condition between subcarrier frequencies to separate each subcarrier at a receiver despite overlapping spectrum. The communication method.

The introduction of orthogonal frequency division multiplexing has made it possible to transmit more data in the same frequency band, but there is still a problem that the frequency band allocated for the wireless communication network system cannot be fully utilized.

In order to solve the above problems, an object of the present invention is to provide a method for reducing inter-cell interference while efficiently using frequencies in a wireless cellular network system.

Moreover, in order to solve the said problem, an object of this invention is to provide the transmitter which can implement the said method.

In order to achieve the above object, the present invention provides a transmission apparatus for use in a wireless cellular communication network system that provides a base station in units of cells of a predetermined area and relays data in an orthogonal frequency division multiplexing scheme using the base station. Encoding means for encoding data; Subcarrier mapping means for mapping the encoded signal and subcarriers for transmitting the encoded signal; And multicarrier modulation means for converting the signal in the mapped frequency domain into a signal in the time domain, wherein the subcarrier mapping means punctures some of the subcarriers used in the wireless cellular communication network system and punctures the subcarrier mapping means. The subcarrier to be provided is a transmission apparatus used in a wireless cellular communication network system, characterized in that different from the subcarrier punctured in the adjacent cell and the cell where the punctured subcarrier is used.

Preferably, the subcarrier mapping means changes the perforated subcarriers at regular intervals.

On the other hand, the encoding means receives the interference information indicating the degree of interference with the signal transmitted from the adjacent cell from the wireless terminal located in the cell, and indicates the degree to spread the signal to be transmitted to the wireless terminal using a spreading code Control means for calculating a diffusion factor; And spreading means for spreading the signal to be transmitted according to the spreading factor calculated by the control means.

On the other hand, the encoding means receives the interference information indicating the degree of interference with the signal transmitted from the adjacent cell from the wireless terminal located in the cell, and indicates the degree to spread the signal to be transmitted to the wireless terminal using a spreading code Control means for calculating a channel coding factor indicative of a spreading factor and a degree of channel coding; Spreading means for spreading a signal to be transmitted according to a spreading factor calculated by the control means; And channel encoding means for performing channel encoding on a signal to be transmitted according to the channel encoding factor calculated by the control means.

Meanwhile, the transmitting apparatus is used for spreading performed in the encoding apparatus of the corresponding cell among carrier patterns corresponding to each spreading code used in the wireless cellular communication network system or each spreading code set which is a set of a predetermined number of spreading codes. Search preamble generating means for generating a signal obtained by modulating predetermined first data known in advance using a carrier of a pattern corresponding to a carrier pattern corresponding to a spreading code; Confirmation preamble generating means for outputting predetermined second data; First multiplexing means for controlling only one of the signal output from the multicarrier modulation means and the signal output from the search preamble generating means to be output from the transmitting apparatus; And second multiplexing means for controlling an output such that only one signal of the data to be transmitted and the signal output from the acknowledgment preamble generating means can be input to the encoding means. The first multiplexing means and the first multiplexing means such that a signal output from the search preamble generating means is output from the first multiplexing means and a signal output from the confirmation preamble generating means is output from the second multiplexing means every cycle. It is preferable to control the second multiplexing means.

Meanwhile, the data transmission between the transmitter and the wireless terminal is performed in a time division duplex and a time division multiple access in which an uplink section and a downlink section are separated from each other. The start time and the end time of the transmission section and the downlink transmission section are synchronized with the neighbor cell, and the transmission apparatus can communicate with each of the wireless terminals requesting the use of radio resources among the wireless terminals located in the corresponding cell. It is preferable to further include a management frame generating means for generating management information including the information allocated to the interval.

In addition, in order to achieve the above object, the present invention is to provide a base station in a cell unit of a predetermined area, and in the transmission apparatus used in a wireless cellular communication network system for relaying data using the base station, a wireless terminal located in the cell Control means for receiving from the interference information indicating a degree of interference with a signal transmitted from an adjacent cell adjacent to the corresponding cell, and calculating a spreading factor indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code; And spreading means for spreading a signal to be transmitted according to a spreading factor calculated by the control means.

In addition, in order to achieve the above object, the present invention is to provide a base station in a cell unit of a predetermined area, and in the transmission apparatus used in a wireless cellular communication network system for relaying data using the base station, a wireless terminal located in the cell Receives interference information indicating the degree of interference with a signal transmitted from an adjacent cell adjacent to the corresponding cell, and indicates a spreading factor and a degree of channel encoding indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code. Control means for calculating a channel encoding factor; Spreading means for spreading a signal to be transmitted according to a spreading factor calculated by the control means; And channel encoding means for performing channel encoding on a signal to be transmitted according to the channel encoding factor calculated by the control means.

In order to achieve the above object, the present invention is to provide a base station in units of cells of a predetermined area, and to spread the data to be transmitted in a transmission apparatus used in a wireless cellular communication network system for relaying data using the base station. Spreading code generating means for generating a spreading code not used in a cell adjacent to the cell; A carrier corresponding to a spreading code used for spreading performed in an encoding apparatus in the corresponding cell among carrier patterns corresponding to each spreading code used in the wireless cellular communication network system or a spreading code set corresponding to each spreading code set which is a set of a predetermined number of spreading codes Search preamble generating means for generating a signal obtained by modulating predetermined first data known in advance using a carrier of a pattern corresponding to the pattern; And confirmation preamble generating means for spreading and outputting predetermined second data by spreading using the spreading code generated by the spreading code generating means. The transmitting apparatus used in the wireless cellular communication network system comprising: Provide

In addition, in order to achieve the above object, the present invention is to provide a base station in units of cells of a predetermined area, and in the transmission method in a wireless cellular communication network system for relaying data in an orthogonal frequency division multiplexing scheme using the base station, a) encoding data to be transmitted; (b) mapping the coded signal and a subcarrier to transmit the coded signal; (c) puncturing a portion of the signal mapped to the subcarrier in step (b); (d) changing and transmitting the signal in the punctured frequency domain to a signal in the time domain, wherein the subcarrier punctured in step (c) is performed in an adjacent cell adjacent to the cell in which the punctured subcarrier is used. Provided is a data transmission method in a wireless cellular communication network system, which is different from a perforated subcarrier.

On the other hand, it is preferable that the subcarrier mapping means changes the perforated subcarriers at regular intervals.

On the other hand, step (a) receives the interference information indicating the degree of interference with the signal transmitted from the adjacent cell from the wireless terminal located in the cell, and transmits a signal to be transmitted to the wireless terminal using a spreading code Calculating a diffusion factor indicating a degree of diffusion; And (ab) performing spreading on a signal to be transmitted according to the spreading factor calculated in step (aa).

On the other hand, step (a) receives the interference information indicating the degree of interference with the signal transmitted from the adjacent cell from the wireless terminal located in the cell, and transmits a signal to be transmitted to the wireless terminal using a spreading code Calculating a diffusion factor indicating a degree of diffusion and a channel encoding factor indicating a degree of channel encoding; (ab) performing spreading on a signal to be transmitted according to the spreading factor calculated in step (aa); And (ac) performing channel encoding on a signal to be transmitted according to the channel encoding factor calculated in step (aa).

Meanwhile, the transmission method includes (e) encoding in the corresponding cell among carrier patterns corresponding to each of the spreading codes used in the wireless cellular communication network system or each spreading code set which is a set of a predetermined number of spreading codes at predetermined periodic intervals. Outputting a search preamble signal obtained by modulating predetermined first data known in advance using a carrier of a pattern corresponding to a carrier pattern corresponding to a spreading code used for spreading performed in the step; and (f) outputting an acknowledgment preamble signal in which spreading is performed on a predetermined second known data using a spreading code used in the corresponding cell.

In order to achieve the above object, the present invention is to provide a base station in a cell unit of a predetermined area, and the transmission method in a wireless cellular communication network system for relaying data using the base station, (a) located in the cell Receiving a interference information indicating a degree of interference with a signal transmitted from an adjacent cell adjacent to the corresponding cell from a wireless terminal, and calculating a spreading factor indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code; And (b) performing spreading on a signal to be transmitted in accordance with the calculated spreading factor.

In order to achieve the above object, the present invention is to provide a base station in a cell unit of a predetermined area, and the transmission method in a wireless cellular communication network system for relaying data using the base station, (a) located in the cell A spreading factor and a channel coding degree indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code by receiving interference information indicating a degree of interference with a signal transmitted from an adjacent cell adjacent to the corresponding cell from the wireless terminal. Calculating a channel encoding factor indicating a; (b) performing spreading on a signal to be transmitted according to the calculated spreading factor; And (c) performing channel encoding on a signal to be transmitted according to the calculated channel encoding factor.

In addition, in order to achieve the above object, the present invention provides a base station in units of cells of a predetermined area and transmits data in a wireless cellular communication network system that relays data using the base station. Generating a spreading code that is not used in a cell adjacent to the cell to spread; (b) a spreading code used for spreading performed in the encoding step in the corresponding cell among carrier patterns corresponding to each spreading code used in the wireless cellular communication network system or a spreading code set corresponding to each spreading code set which is a set of a predetermined number of spreading codes. Outputting a search preamble signal obtained by modulating predetermined first data known using a carrier of a pattern corresponding to a corresponding carrier pattern; And (c) outputting an acknowledgment preamble signal obtained by spreading predetermined second data in advance by using the generated spreading code. do

In order to achieve the above object, the present invention provides a data transmission method in a wireless cellular communication network system in which a base station is installed in units of cells of a predetermined area and relays data using the base station. Setting a superframe configured with a time division duplex in synchronization with a neighboring cell adjacent to a corresponding cell to which data is transmitted through; (b) A time division multiple access method for a wireless terminal requesting the use of radio resources in time division multiple access in the uplink transmission section and the downlink transmission section of the superframe, respectively. Allocating a random access time period during which the wireless terminal which does not request the use of the radio resource can request the use of the radio resource; And (c) transmitting management information including the information set in step (a) and step (b).

In the step (b), it is preferable that the random access time period is divided into terminals that do not request the use of the radio resource into predetermined groups, and different time intervals are allocated to the divided predetermined groups.

On the other hand, in the step (a) it is preferable that the synchronization with the adjacent cell is adjusted using a Global Positioning System (GPS).

In order to achieve the above object, the present invention provides a data transmission method in a wireless cellular communication network system in which a base station is provided in units of cells of a predetermined area and relays data using the base station. Setting a predetermined carrier set corresponding to the corresponding one-to-one; (b) transmitting predetermined data in advance when the predetermined message is to be transmitted using a carrier set corresponding to the message to be transmitted; data in a wireless cellular communication network system, comprising: Provide a transmission method.

The present invention also provides a computer readable recording medium having recorded thereon a program for realizing the above method.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram showing the configuration of the transmission apparatus of the present invention.

The data 201 input to the transmitting apparatus of the present invention includes a first multiplexer 204, a channel encoding means 205, an interleaving means 206, a spreading means 207, a subcarrier mapping means 211, and an IFFT 212. And serialization means 213, protection interval extension means 214, second multiplexer 215, pulse shaping means 216, and transmitted through a component including a transmission means 217.

In addition, the transmitting apparatus of the present invention includes a search preamble generating means 209 and a confirmation preamble generating means 203 in order to enable the wireless terminal to obtain a spreading code. The management frame generating means 202 is provided for generating. Such components are controlled by the control means 208.

Each component is as follows.

The search preamble generating means 209 generates a set of carriers representing a spreading code used for spreading in the transmission apparatus of the present invention.

In a wireless cellular network system in which the present invention is used, each cell spreads data to be transmitted using a spreading code different from that used in a unique or at least adjacent cell. Accordingly, even when using the same frequency band as the adjacent cells there is an advantage that can cause less interference with each other due to different spreading codes.

The present invention is characterized in that a subcarrier pattern is set in advance so as to correspond to all such spreading codes in a 1: 1 manner or divide the spreading codes into predetermined groups, and have a 1: 1 correspondence to each spreading code group. The preamble generating means 209 generates a subcarrier pattern corresponding to the spreading code used for spreading in the transmission apparatus of the present invention.

For example, if the total number of spreading codes used in the wireless cellular network system of the present invention is 48, the first spreading code is represented by a subcarrier set consisting of subcarriers 1, 3, and 5 of the used subcarriers. The second spreading code promises a subcarrier set corresponding to each spreading code in advance in such a manner that it is represented by a subcarrier set consisting of subcarriers 2, 4, and 6 of the used subcarriers. The search preamble generating means 209 generates and transmits a search preamble signal modulated with predetermined data using a promised subcarrier set to indicate what spreading code is used in the corresponding cell.

Each radio terminal demodulates it, determines the best reception state among each subcarrier set, and finds the access point to which it belongs and the spreading code used by the base station.

Each subcarrier set may correspond to one spreading code as described above. However, when the number of spreading codes used in the wireless cellular communication network system is large, a set of codes is generated by grouping them into a predetermined unit and then searching preamble generating means 209 ) May facilitate the code synchronization acquisition of the wireless terminal by first transmitting a search preamble for a code set and then transmitting code information in the code set to the search preamble.

For example, if there are 100 types of spreading codes used in the whole system, spreading codes 1 to 25 correspond to the subcarrier set of pattern 1, and spreading codes 26 to 50 are 2 times. Subcarrier patterns can be matched 1: 1 for each spreading code group in such a manner as to correspond to a subcarrier set of a pattern, and a preset subcarrier set corresponding to each spreading code in each group can be set in advance. have.

In this case, the search preamble generating means 209 first modulates and transmits predetermined data by using a subcarrier set for a spreading code group to which a spreading code group used in a corresponding cell belongs, and again in the spreading code group. A subcarrier set corresponding to a spreading code in Equation 9 is transmitted.

The acknowledgment preamble generating means 203 outputs predetermined data known in advance, and the output data is transmitted as an acknowledgment preamble signal spread using a spreading code used in the corresponding cell.

The wireless terminal despreads the received acknowledgment preamble signal using a spreading code obtained from the search preamble signal. If the correlation value is higher than a certain level, the wireless terminal confirms that the spreading code acquisition has been successfully performed.

The channel encoding means 205 performs channel encoding, such as error correction encoding, on the data to be transmitted. Such a channel encoding means includes a convolutional encoder and a turbo encoder. Detailed description of channel encoding is well known to those skilled in the art to which the present invention pertains, and thus a detailed description thereof will be omitted.

The encoding rate of the channel encoding performed by the channel encoding means 205 is determined according to the control of the control means 208, and the control means 208 determines the encoding rate using information on the degree of interference received from the wireless terminal. do.

The interleaving means 206 interleaves the signal output from the channel encoding means 205. Such interleaving means include a convolutional interleaver, a block interleaver and an algebraic interleaver. Since the information on the interleaving is general in the art, a detailed description thereof will be omitted.

The spreading means 207 spreads the interleaved signal by using a direct spreading method using a spreading code used in a corresponding cell.

The spreading factor (factor), which is a spreading degree performed by the spreading means 207, is determined according to the control of the control means 208, and the control means 208 spreads using information on the degree of interference received from the wireless terminal. Determine the factor.

The subcarrier mapping means 211 maps a signal encoded by the encoding means 210 to a subcarrier to be used, punctures a portion thereof, and then distributes the signal. Specific functions will be described later in detail.

Inverse Fast Fourier Transformer (IFFT) 212 converts a signal in the frequency domain output from the subcarrier mapping means 211 into a signal in the time domain.

The serialization means 213 converts the signal output from the IFFT 212 into a parallel-to-serial.

The guard interval extension means 214 is a guard interval in units of data carried on a subcarrier in order to prevent the case in which the first transmitted packet arrives later than the later transmitted packet because multiple paths for transmitting data exist during data transmission. (guard time) is inserted.

Pulse shaping means 216 smoothes the waveform using a baseband filter to perform shaping so that the signal does not exceed a given frequency bandwidth.

The transmitting means 217 converts the digital signal output from the pulse forming means 216 into an analog signal and outputs it to the outside.

Since the IFFT 212, the serialization means 213, the guard interval expansion means 214, the pulse shaping means 216 and the transmission means 217 is a component generally used in a system using an orthogonal frequency division multiplexing method. Further explanation is omitted here.

The management frame generating means 202 is a synchronization information for the superframe used in the system of the present invention, the timeslot allocation information for each radio terminal can use the radio resources, that is, for the following downlink transmission frame and uplink transmission frame A management frame is generated using management information including resource allocation information, information on an encoding factor indicating a coding rate of a signal transmitted to each radio terminal, information on a spreading factor indicating a spreading degree, and the like.

The management frame further includes information on a frame number, a data packet received in a previous super frame, and an acknowledgment (ACK) for a random access packet.

Control means 208 controls each of the above components as a whole. Specifically, the control means 208 performs the following operations.

A channel coding factor indicating the channel coding degree and a spreading factor indicating the spreading degree are calculated and transmitted according to the degree of interference with the adjacent cell transmitted from the wireless terminal, and interleaving when the channel coding means 205 changes the channel coding rate. Since there should also be a change, information about this is also transmitted to the interleaving means 206.

In addition, the management frame generation means 202, the search preamble generation means 209, and the confirmation preamble generation means 203 are controlled at a predetermined period in response to the synchronization signal and thus the management frame signal, the search preamble signal, and the confirmation preamble signal. Etc. can be output, and the first multiplexer 204 and the second multiplexer 215 are controlled to control which signals are output in each case.

The search preamble generating means 209, the confirmation preamble generating means 203, the management frame generating means 202, and the related components among the above components may be used only in the transmission apparatus used in the base station, but other components. Is used under the same conditions in the wireless terminal.

More detailed features of the present invention will be described in detail with reference to FIGS. 3 to 10 in relation to the transmitter shown in FIG. 2.

One of the characteristics of the present invention is a superframe in which uplink and downlink frames in a cell are time division multiplexed (TDD) according to a predetermined time slot and guard time. Super Frame) structure.

3 is a diagram illustrating the structure of such a superframe, the superframe of the present invention is composed of a downlink management frame 301, a downlink transmission frame 302, an uplink transmission frame 303, and uplink transmission and downlink transmission Even when the same frequency band is used, interference does not occur with each other.

Here, uplink transmission refers to data transmission from a wireless terminal located in a cell to a base station, and downlink transmission refers to data transmission from a base station to a wireless terminal.

Another feature of the present invention is to use Time Division Multiple Access (TDMA), which allows only one communication at any one time. Due to this feature, even if a base station and all radio terminals located in a cell transmit a spread signal using the same spreading code in the same frequency band, there is no possibility of interference with other signals.

In addition, since communication is performed only between the base station and any one wireless terminal at any one time, the transmitter of the present invention uses a directional antenna to form a beam so that radio waves are transmitted only in a direction in which the wireless terminal to communicate is located. By doing so, there is an advantage that the effect of interference on neighboring cells can be reduced as much as possible.

In order to use the TDMA scheme, the management frame generation unit 202 allocates timeslots for using radio resources to the radio terminals requesting the use of radio resources, and informs them of the management frame 301.

Another feature of the present invention related to superframe is that the present invention is synchronized with each cell.

As shown in FIG. 4, the superframe length, the superframe start time, the uplink and downlink frames, etc. of all cells are exactly synchronized.

For this synchronization, each base station directly receives a GPS (Global Positioning System) signal or a GPS-compliant means including GPS-based time information, such as a downlink signal of an IS-95 CDMA network. GPS information included in the broadcast channel is extracted and synchronized.

Accordingly, a network configuration effect occurs in which uplink and downlink channels between different cells do not cause mutual interference.

That is, since the same frequency band can be used in all the cells of the present invention, if the cells are not synchronized with each other, the cell 1 is in the downlink frame state and the cell 2 is in the uplink frame state. In the case of a wireless terminal located near the boundary area of cell 1 and cell 2 in the area of, in some cases, the wireless terminal located near the boundary area of cell 1 and cell 2 in the area of cell 2 than the signal transmitted from the base station of cell 1 Signal transmitted to the base station of cell 2 can be received larger and clearer, so that the signal transmitted from the cell 2 radio terminal is received at a much higher level than the base station transmit signal of cell 1 to be received, which can cause considerable interference. have.

However, in the present invention, the above problem does not occur because the cell and the cell are synchronized with each other.

A configuration of the superframe as described above and a method of assigning each time slot are shown in FIG. 5.

The management frame generating means 202 configures a superframe composed of a downlink management frame 301, a downlink transmission frame 302, and an uplink transmission frame 303 by using synchronization information with an adjacent cell (501).

In addition, the management frame generating means 202 is a preemption time for each radio terminal to use radio resources in the downlink frame 302 and the uplink frame 303 for the radio terminal requesting the allocation of radio resources in the preceding frame. Allocates a slot (502).

The uplink frame 303 is provided with a random access time slot used when a radio terminal not requesting a radio resource requests a radio resource in addition to the preemption time slot.

The random access timeslot may be made available to any wireless terminal that has not been occupied. However, in this case, when a plurality of radio resource use requests are received at the same time, the random access timeslot may interfere with each other. It is preferable to divide the wireless terminals that are not allocated the occupancy time slot into groups of as many random access timeslots and assign one random access timeslot to each group.

The management frame generating means 202 includes the information generated through the above process in the management information transmitted to the management frame 301 and transmits it to each wireless terminal (503), and each wireless terminal according to the management information. Transmit and receive data with the base station in the assigned timeslot.

6 shows a process in which a base station and a wireless terminal reach data transmission and reception.

First, when the wireless terminal enters the cell where the base station is located or powers up in the cell, the base station recognizes the wireless terminal and allocates a random access timeslot to the wireless terminal (601). However, if the qualification for using the random access timeslot is not set separately, it is not necessary to allocate a separate random access timeslot.

The search preamble generation means 209 and the confirmation preamble generation means 203 generate and transmit the search preamble signal and the confirmation preamble signal at predetermined intervals under the control of the control means 208.

First, the search preamble generating means 209 generates a search preamble signal and outputs it (602). The search preamble generating unit 209 is a spreading code used for spreading in a corresponding cell among carrier patterns corresponding to each spreading code set or a spreading code set which is a set of a predetermined number of spreading codes used in the wireless cellular communication network system of the present invention. A search preamble signal obtained by modulating predetermined data known in advance is output using a carrier of a pattern corresponding to a carrier pattern corresponding to.

After demodulating the wireless terminal, the wireless terminal determines the best reception state among each subcarrier set, and thus finds a base station to which it belongs and an spreading code used by the base station (603).

The acknowledgment preamble generating means 203 spreads the known data using a spreading code corresponding to the subcarrier set transmitted by the search preamble generating means 209 and then transmits it.

In this case, it is preferable that the encoding degree and the spreading degree of the acknowledgment preamble signal are determined in advance, and the information related to the identification of the most basic spreading code in the transmission and reception of data in the cell. More preferably, encoding and spreading are performed at the encoding level and the maximum spreading rate.

The wireless terminal despreads the received acknowledgment preamble signal using a spreading code obtained from the search preamble signal. If the correlation value is higher than a certain level, the wireless terminal confirms that the spreading code acquisition has been successfully performed (605). ).

The management frame generation means 202 periodically transmits a management frame signal in synchronization with the synchronization (606). The management frame signal is set with a random access timeslot for requesting the use of radio resources.

In the above description, the discovery preamble transmission 602, the acknowledgment preamble transmission 604, and the management frame transmission 606 are sequentially described. However, this is merely an example, and the discovery preamble signal and the acknowledgment preamble signal are stored in the management information. The order shown in FIG. 6 may be included and transmitted when the management frame is included, but does not limit the scope of the present invention.

When the user of the wireless terminal wants to transmit and receive data using the wireless terminal, the wireless terminal transmits a random access signal requesting the use of radio resources to the allocated random access timeslot (607).

Further, at any time during the communication, the wireless terminal may report to the base station information on the degree of interference indicating the signal received from the base station of the cell where the wireless terminal is located and the size of the signal received in the adjacent cell.

In this case, the wireless terminal may not only report information on the degree of interference, but may also request a desired channel coding rate and spreading degree according to the degree of interference.

Upon receiving the random access signal or the interference report as described above, the base station allocates a preemption time slot that can be occupied by the radio terminal (609) when generating a subsequent management frame (609). The channel coding factor and the spreading factor indicating the channel coding rate and the spreading rate are set and transmitted.

When the time slots occupied by the wireless terminal are allocated, data transmission and reception between the wireless terminal and the base station starts in earnest (611).

7 is a flowchart illustrating a method of transmitting data in a transmitting apparatus.

The control means 208 receives information indicating the degree of interference from the wireless terminal (701), and determines the spreading factor and the channel coding factor according to the degree of interference (702). Instead of this process, the transmitter of the wireless terminal measures the degree of interference and transmits it to the base station (not shown).

There may be various methods for determining the spreading factor and the channel coding factor as described above. However, in the control means 208, the preferred coding factor and the spreading factor and the interleaving method according to each interference degree are provided in the form of a lookup table. It is desirable to store and determine a desired coding factor and spreading factor according to the received interference degree report.

Here, the coding factor indicating the coding rate is a term indicating how many output symbols the channel encoding means 205 generates for one input symbol. When the coding factor 205 generates two output symbols for one input symbol, 1/2.

The receiver performs channel decoding to demodulate the symbol. Generally, the lower the coding rate, the higher the gain on reception performance due to channel coding, that is, the coding gain.

Spreading Factor is a term indicating how many spreading output symbols the spreading means 207 generates for one input symbol. If the spreading factor 207 generates four spreading output symbols for one input symbol, the spreading factor becomes four. . If the spreading factor is 1, no spreading occurs and a randomization (or whitening) effect is obtained by a spreading code (PN code).

The spreading means 207 includes a spreading code generator (not shown) for outputting a spreading code used in a corresponding cell therein, and the spreading code generator always generates 1 when the spreading factor is larger than 1 It is also possible to obtain a repeating effect in which the symbol is repeated by the spreading factor.

When the inter-cell interference level measured by the radio terminal is low-In general, when the radio terminal is far from the boundary area with the adjacent cell, and adjacent to the base station of the cell-the encoding means 210 is a low level Coding Gain, Spreading Gain, and Frequency Diversity Gain are provided.

In this case, since there is not much redundancy added by the encoding means 210, the base station and the wireless terminal can transmit and receive at a high source data rate. If a cell is located in an environment where the interference level from a neighboring cell is sufficiently low, the base station and the wireless terminal belonging to the cell can always transmit and receive at a high source data rate.

In this case, frequency diversity is a term indicating how many subcarriers are used to transmit a plurality of output symbols generated after one input symbol has been channelized, interleaved, and spread. Have the same value. For example, if one symbol is channel-coded at 1/2 coding rate and then spread to spreading factor 6, the number of output symbols is 12. If all of them are mapped to different subcarriers and transmitted, the frequency diversity of the subcarriers The value is 12.

In general, frequency diversity refers to a technique for improving reception performance by transmitting and receiving the same information over a plurality of different frequency bands, and the gain on the reception performance obtained through this is called frequency diversity gain. In the transmission apparatus of the present invention, a frequency diversity effect occurs when the output of the encoding means 210 is mapped to a plurality of subcarriers by the subcarrier mapping means 211.

If the intercell interference degree measured by the wireless terminal is increased, the encoding means 210 is set to provide more gain by the control means 208, which results in lowering the source data rate.

In this case, the encoding means 210 may either (1) reduce the coding rate of channel coding (e.g., 1/2-> 1/12, or more output symbols for one symbol), or (2) increase the spreading factor. Or (eg 1-> 6). By performing both (3), (1), and (2), it is possible to overcome the inter-cell interference at the receiving side.

The frequency diversity effect is increased by a process in which output symbols of the encoding means 210 generated by the above process are mapped and transmitted to a plurality of subcarriers.

8 shows an example of an internal operation of the encoding means 210. For convenience of explanation, the interleaving means 206 and the spreading code generator are omitted in the drawing.

Example 1 shows a case where a wireless terminal and a base station that experience low intercell interference levels transmit and receive data with each other. Example 2 shows a case where a wireless terminal and a base station that experience high levels of inter-cell interference transmit and receive data with each other, and show that the spreading factor is increased from 1 to 6 compared to Example 1. Example 3 is also for overcoming a high degree of intercell interference, and shows a state in which a coding rate is reduced from 1/2 to 1/12, that is, set to provide a larger coding gain compared to Example 1. As described above, the coding rate and the spreading factor may be simultaneously adjusted.

When the channel encoding factor and the spreading factor are set according to the degree of inter-cell interference, the encoding means 210 performs encoding accordingly (703).

The encoded signal is input to the subcarrier mapping means 211 and mapped to each subcarrier (704).

The subcarrier mapping means 211 also punctures some of the subcarriers used (705). Subcarrier puncturing is a technique for preventing a corresponding subcarrier band from interfering with another cell by not using a specific subcarrier set for each base station. At this time, each base station has a different subcarrier puncturing pattern, which may change in a fixed or constant time period.

FIG. 9 shows an example of performing two subcarrier puncturings for every eight adjacent subcarriers for each cell. In the case of cell 1, the subcarriers located at 0 and 7th were punched, and in the case of cell 4, the subcarriers located at 2nd and 4th were punched.

FIG. 10 conceptually illustrates how the inter-cell interference received by the wireless terminal in the inter-cell boundary when subcarrier puncturing is performed for each subcarrier.

FIG. 10 illustrates a case where the wireless terminal is located in an area adjacent to cells 1 and 4 of the cell 3 region, and in cell 3, the subcarriers 1 and 3 are punctured. The degree is high.

On the other hand, since 0 and 7 subcarriers are punctured in cell 1, and 2 and 4 subcarriers are punctured in cell 4, the interference degree is relatively low, and thus, a cleaner signal can be received.

After the puncturing of the subcarriers is performed, the subcarriers are dispersed (706). When the subcarriers are not detected, interleaving performed by the interleaving means 206 is a process of distributing the order in order to prevent the case where the entire information transmitted on the subcarriers of the specific area cannot be detected. Although similar to the interleaving performed by the interleaving means 206, the subcarrier mapping means 211 has a difference in that it distributes only within a subcarrier set input to the IFFT 212 at one time.

The signal output from the subcarrier mapping means 211 is input to the IFFT 212 and converted from the frequency domain to the time domain (707), and the signal is serialized means 213, guard interval expansion means 214, pulse shaping means. 216 is modulated and transmitted via the transmission means 217 (708).

Another feature of the present invention is a method of enabling a specific subcarrier set for each message in transmitting a simple message. After establishing mutual correspondence between N different messages and N subcarrier sets, and using a corresponding subcarrier set to deliver a specific message, a simple message can be exchanged. In this case, the transmitted data uses a known value and the receiver side knows which subcarrier set the sender uses by correlating the received signal with a known value for all subcarrier sets. Examples of messages that can be delivered in this manner include ACK, NACK, and Random Access Request.

The method of the present invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

As described above, according to the present invention, there is an advantage that the inter-cell interference can be prevented while the frequency can be used efficiently.

1 illustrates the concept of a cellular network system

2 is a block diagram showing the configuration of the transmission apparatus of the present invention.

3 is a diagram illustrating a superframe structure of the present invention.

4 illustrates a synchronization result with a cell of the present invention.

5 is a flowchart illustrating a method of setting a superframe in the present invention.

6 is a flowchart illustrating a method for starting data transmission and reception in a base station and a wireless terminal in the present invention.

7 is a flowchart illustrating a data transmission method of the present invention.

8 illustrates an example of encoding of the present invention.

9 illustrates an example of subcarrier drilling of the present invention.

10 is a diagram illustrating the effect of subcarrier puncturing of the present invention.

Claims (22)

A transmission apparatus used in a wireless cellular communication network system in which a base station is provided in units of cells of a predetermined area and relays data using an orthogonal frequency division multiplexing method using the base station. Encoding means for encoding data to be transmitted; Subcarrier mapping means for mapping the encoded signal and subcarriers for transmitting the encoded signal; And multicarrier modulation means for converting the signal in the mapped frequency domain into a signal in the time domain. The subcarrier mapping means punctures some of the subcarriers used in the wireless cellular communication network system, and the subcarriers punctured by the subcarrier mapping means are different from subcarriers punctured in adjacent cells adjacent to the cell where the punctured subcarriers are used. A transmitter for use in a wireless cellular network system, characterized in that. The transmission apparatus of claim 1, wherein the subcarrier mapping means changes the perforated subcarriers at predetermined intervals. The method of claim 1, wherein the encoding means Control for calculating a spreading factor indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code by receiving interference information indicating a degree of interference with a signal transmitted from the neighboring cell from a wireless terminal located in the corresponding cell; Way; And And spreading means for spreading the signal to be transmitted according to the spreading factor calculated by the control means. The method of claim 1, wherein the encoding means A spreading factor and a channel encoding method for receiving the interference information indicating the degree of interference with the signal transmitted from the neighboring cell from the wireless terminal located in the corresponding cell and spreading the signal to be transmitted to the wireless terminal using a spreading code. Control means for calculating a channel coding factor indicating a degree; Spreading means for spreading a signal to be transmitted according to a spreading factor calculated by the control means; And And channel encoding means for performing channel encoding on a signal to be transmitted according to the channel encoding factor calculated by the control means. The method of claim 1, wherein the transmitting device A carrier corresponding to a spreading code used for spreading performed in an encoding apparatus in the corresponding cell among carrier patterns corresponding to each spreading code used in the wireless cellular communication network system or a spreading code set corresponding to each spreading code set which is a set of a predetermined number of spreading codes Search preamble generating means for generating a signal obtained by modulating predetermined first data known in advance using a carrier of a pattern corresponding to the pattern; Confirmation preamble generating means for outputting predetermined second data; First multiplexing means for controlling only one of the signal output from the multicarrier modulation means and the signal output from the search preamble generating means to be output from the transmitting apparatus; And A second multiplexing means for controlling an output such that only one of the data to be transmitted and the signal output from the acknowledgment preamble generating means is input to the encoding means; The control unit may be configured to output the signal output from the search preamble generating means to the first multiplexing means and output the signal output from the confirmation preamble generating means to the second multiplexing means every predetermined period. A transmission apparatus for use in a wireless cellular communication network system, characterized in that said first multiplexing means and said second multiplexing means are controlled. The data transmission method of claim 1, wherein the data transmission between the transmitter and the wireless terminal is performed by a time division duplex method and a time division multiple access method in which an uplink section and a downlink section are separated from each other. The start and end times of the uplink section and the downlink section are synchronized with the neighboring cell. Management frame generation means for generating management information including information for allocating a communication time interval for each of the wireless terminals requesting the use of radio resources among the wireless terminals located in the corresponding cell; Transmission equipment used in cellular network systems. A transmission apparatus used in a wireless cellular communication network system for providing a base station in units of cells of a predetermined area and relaying data using the base station, A spreading factor indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code by receiving interference information indicating a degree of interference with a signal transmitted from an adjacent cell adjacent to the corresponding cell from a wireless terminal located in the corresponding cell; Calculating means; And And spreading means for spreading the signal to be transmitted according to the spreading factor calculated by the control means. A transmission apparatus used in a wireless cellular communication network system for providing a base station in units of cells of a predetermined area and relaying data using the base station, A spreading factor indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code, by receiving interference information indicating a degree of interference with a signal transmitted from an adjacent cell adjacent to the corresponding cell from a wireless terminal located in the corresponding cell; Control means for calculating a channel encoding factor indicative of the degree of channel encoding; Spreading means for spreading a signal to be transmitted according to a spreading factor calculated by the control means; And And channel encoding means for performing channel encoding on a signal to be transmitted according to the channel encoding factor calculated by the control means. A transmission apparatus used in a wireless cellular communication network system for providing a base station in units of cells of a predetermined area and relaying data using the base station, Spreading code generating means for generating a spreading code that is not used in a cell adjacent to the cell to spread the transmitted data; A carrier corresponding to a spreading code used for spreading performed in an encoding apparatus in the corresponding cell among carrier patterns corresponding to each spreading code used in the wireless cellular communication network system or a spreading code set corresponding to each spreading code set which is a set of a predetermined number of spreading codes Search preamble generating means for generating a signal obtained by modulating predetermined first data known in advance using a carrier of a pattern corresponding to the pattern; And And confirmation preamble generating means for spreading and outputting predetermined second data using a spreading code generated by said spreading code generating means. A transmission method in a wireless cellular communication network system in which a base station is provided in units of cells of a predetermined area and relays data using an orthogonal frequency division multiplexing method using the base station. (a) encoding the data to be transmitted; (b) mapping the coded signal and a subcarrier to transmit the coded signal; (c) puncturing a portion of the signal mapped to the subcarrier in step (b); (d) changing and transmitting the signal in the punctured frequency domain to a signal in the time domain, wherein the subcarrier punctured in step (c) is performed in an adjacent cell adjacent to the cell in which the punctured subcarrier is used. A method of transmitting data in a wireless cellular communication network system, which is different from a subcarrier to be punctured. The method of claim 10, wherein the subcarrier mapping means changes the perforated subcarriers at predetermined intervals. The method of claim 10, wherein step (a) (aa) a spreading factor indicating a degree of spreading a signal to be transmitted to the wireless terminal by using a spreading code by receiving interference information indicating a degree of interference with a signal transmitted from the neighboring cell from a wireless terminal located in the corresponding cell; Calculating; And (ab) spreading a signal to be transmitted according to the spreading factor calculated in step (aa); and transmitting the data in a wireless cellular communication network system. The method of claim 10, wherein step (a) (aa) a spreading factor indicating a degree of spreading a signal to be transmitted to the wireless terminal by using a spreading code by receiving interference information indicating a degree of interference with a signal transmitted from the adjacent cell from a wireless terminal located in the corresponding cell; Calculating a channel encoding factor indicative of the degree of channel encoding; (ab) performing spreading on a signal to be transmitted according to the spreading factor calculated in step (aa); And and (c) performing channel encoding on a signal to be transmitted according to the channel encoding factor calculated in step (aa). The method of claim 10, wherein the transmission method (e) spreading performed in the encoding step of the corresponding cell among carrier patterns corresponding to each spreading code used in the wireless cellular communication network system or a spreading code set which is a set of a predetermined number of spreading codes at predetermined periodic intervals. Outputting a search preamble signal obtained by modulating predetermined first data known in advance using a carrier of a pattern corresponding to a carrier pattern corresponding to a spreading code used; (f) outputting an acknowledgment preamble signal obtained by spreading using a spreading code used in the corresponding cell with respect to predetermined second data. How to send data. A transmission method in a wireless cellular communication network system in which a base station is provided in units of cells of a predetermined area and relays data using the base station. (a) receiving interference information indicating a degree of interference with a signal transmitted from an adjacent cell adjacent to the corresponding cell from a wireless terminal located in the corresponding cell, and indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code; Calculating a diffusion factor; And and (b) performing spreading on a signal to be transmitted according to the calculated spreading factor. A transmission method in a wireless cellular communication network system in which a base station is provided in units of cells of a predetermined area and relays data using the base station. (a) receiving interference information indicating a degree of interference with a signal transmitted from an adjacent cell adjacent to the corresponding cell from a wireless terminal located in the corresponding cell, and indicating a degree of spreading a signal to be transmitted to the wireless terminal using a spreading code; Calculating a channel coding factor indicative of a spreading factor and a degree of channel coding; (b) performing spreading on a signal to be transmitted according to the calculated spreading factor; And and (c) performing channel encoding on a signal to be transmitted according to the calculated channel encoding factor. A transmission method in a wireless cellular communication network system in which a base station is provided in units of cells of a predetermined area and relays data using the base station. (a) generating a spreading code that is not used in a cell adjacent to the cell to spread the transmitting data; (b) a spreading code used for spreading performed in the encoding step in the corresponding cell among carrier patterns corresponding to each spreading code used in the wireless cellular communication network system or a spreading code set corresponding to each spreading code set which is a set of a predetermined number of spreading codes. Outputting a search preamble signal obtained by modulating predetermined first data known using a carrier of a pattern corresponding to a corresponding carrier pattern; And and (c) outputting an acknowledgment preamble signal obtained by spreading predetermined second data using the generated spreading code. A data transmission method in a wireless cellular communication network system in which a base station is provided in units of cells of a predetermined area and relays data using the base station. (a) setting a superframe configured with a time division duplex in synchronization with an adjacent cell adjacent to a corresponding cell to which data is transmitted through the base station; (b) A time division multiple access method for a wireless terminal requesting the use of radio resources in time division multiple access in the uplink transmission section and the downlink transmission section of the superframe, respectively. Allocating a random access time period during which the wireless terminal which does not request the use of the radio resource can request the use of the radio resource; And and (c) transmitting management information including the information set in the steps (a) and (b). 19. The method of claim 18, wherein in the step (b), the random access time period is divided into terminals that do not request the use of the radio resource into predetermined groups, and different time intervals are allocated to the divided predetermined groups. A data transmission method in a wireless cellular communication network system. 19. The method of claim 18, wherein in step (a), the synchronization with the neighboring cell is coordinated using a Global Positioning System (GPS). A data transmission method in a wireless cellular communication network system in which a base station is provided in units of cells of a predetermined area and relays data using the base station. (a) setting a predetermined carrier set corresponding to the predetermined message in a 1: 1 correspondence; (b) transmitting predetermined data in advance when the predetermined message is to be transmitted using a carrier set corresponding to the message to be transmitted; data in a wireless cellular communication network system, comprising: Transmission method A computer-readable recording medium having recorded thereon a program for realizing the method according to any one of claims 10 to 21.