KR101019338B1 - Method for data transmission and reception, and apparatus supporting the method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable internet system, and more particularly, to a data transmitting / receiving method and an apparatus supporting the same capable of improving the performance of signal detection.

In the data transmission method according to an embodiment of the present invention, in the data transmission method of the portable Internet system, a power weight value that increases or decreases the power value of the original subcarrier signal based on a channel state at the time of initial network entry. Defining subcarrier groups to which the power weight value is applied; A positive power weight value is assigned to subcarriers of a first subcarrier group among the subcarrier groups, and the positive power weight value is assigned to subcarriers of a second subcarrier group neighboring the first subcarrier group. Assigning a negative power weight value that is symmetrical with; And modulating the subcarriers to which the power weight value is applied to a transmission signal and transmitting the modulated subcarriers to a receiver through a plurality of antennas.

MIMO, SNR, QAM, MMSE-OSIC, PUSC

Description

Method for data transmission and reception, and apparatus supporting the method

The present invention relates to a method for transmitting and receiving data that can improve the performance of signal detection and an apparatus supporting the same.

The portable Internet system according to the IEEE 802.16 technology standard uses an orthogonal frequency division multiplexing (OFDM) transmission method to enable high-speed data service even when a terminal is moving, and the OFDMA enables multiple terminals to simultaneously receive communication service. Use a multiple access scheme such as (Orthogonal Frequency Division Multiple Access).

In such a portable Internet system, MIMO (multiple input multiple output) technology using a plurality of antennas is being applied to a transmitter (base station) and a receiver (terminal) in order to increase the data transmission rate within a limited resource.

In order to improve data transmission efficiency, a transmitter according to the MIMO technology uses a spatial multiplexing (SM) method in which a transmission symbol is multi-divided and transmitted through a plurality of transmission antennas. For example, in the case of “2 * 2” in which two antennas are formed at the transmitter and the receiver, two different data streams may be simultaneously transmitted at the same time.

The receiver detects different data streams from the signals received through the two antennas, combines the detected data streams, and decodes the original data. At this time, the received data is restored using signal detection methods such as maximum likelihood (ML), minimum mean square error (MMSE), order successive interference cancellation (OSIC), and MMSE-OSIC.

First, the MMSE method is a linear signal detection method, which refers to a technique of detecting a signal by finding a matrix maximizing SNR in a received signal and recovering data from the detected signal. Subsequently, the OSIC method is a non-linear signal detection method, and means a technique of reducing interference effects between signals by sequentially removing the detected signals from the received signals according to the detection order or the strength of the detected signals.

The MMSE-OSIC method combines the advantages of the MMSE method and the OSIC method. Therefore, when the MIMO technology is applied, the MMSE-OSIC method is preferred as a signal detection method in the receiver.

However, the MMSE-OSIC method or the OSIC method basically improves the signal detection performance as the difference in the strength (power) of the plurality of received signal values increases, where the signal strength value is determined by the power value and the channel of the signal determined at the time of transmission. It depends on the situation.

However, since the power values (strengths) of signals that are multi-divided and transmitted through a plurality of antennas are set to be identically transmitted within the same frame and transmitted, when the channel states of the plurality of signals are the same or similar, The difference in power values can be made smaller. Accordingly, there is a problem in that signal detection performance is lowered because interference effects between received signals cannot be reduced.

Disclosure of Invention The present invention has been made in view of the above-described problems, and it is a technical object of the present invention to provide a data transmission / reception method capable of improving the performance of detection of a received signal.

Disclosure of Invention The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a base station for transmitting a MIMO signal so as to improve reception signal detection performance.

In the data transmission method according to an embodiment of the present invention for achieving the above object, in the data transmission method of the portable Internet system, the power value of the original subcarrier signal based on the channel state at the time of initial network entry (initial network entry) Defining a power weight value to increase or decrease a value and subcarrier groups to which the power weight value is applied; A positive power weight value is assigned to subcarriers of a first subcarrier group among the subcarrier groups, and the positive power weight value is assigned to subcarriers of a second subcarrier group neighboring the first subcarrier group. Assigning a negative power weight value that is symmetrical with; And modulating the subcarriers to which the power weight value is applied to a transmission signal and transmitting the modulated subcarriers to a receiver through a plurality of antennas.

In the data receiving method according to an embodiment of the present invention for achieving the above object, in the data receiving method of the portable Internet system, a power weight value for increasing or decreasing the power value of the original subcarrier signal for each group of subcarriers is added. Receiving the received subcarriers through the plurality of antennas; Detecting the received subcarriers using a signal detection scheme based on a difference in power values of the subcarriers; Changing an estimated channel of received subcarriers based on a power weight value assigned to each of the subcarrier groups; And restoring the detected subcarriers to original data based on the changed channel.

A data transmission method according to an embodiment of the present invention for achieving the above object is a data transmission method of a portable Internet system using a MIMO method, comprising a first pilot and a first data through a first transmission antenna; Transmitting one stream; Transmitting a second stream comprising second pilots and second data via a second transmit antenna, wherein the first pilot and the second pilot set the same transmit power, and the first data and the The second data is characterized by setting different transmission powers.

According to an aspect of the present invention, there is provided a transmission apparatus of a portable Internet system using a MIMO system, comprising: a MIMO encoder for encoding an input data signal to be suitable for a MIMO method; A sub channel mapping unit for mapping the data signal from the MIMO encoder to a sub channel; Set a power weight to change the power value of the data signal based on the subchannel, give a positive power weight value to the subcarriers of the first subcarrier group from among a plurality of subcarrier groups, and the first sub A power controller for giving subcarriers of a second subcarrier group adjacent to the carrier group to a negative power weight value symmetrical with the positive power weight value; A signal processor converting the power weighted subcarriers into a band signal; And a transmitter for transmitting the band signal from the signal processor through a plurality of antennas.

According to an aspect of the present invention, there is provided a receiving apparatus of a portable Internet system using a MIMO method, comprising: a receiving unit receiving subcarriers through a plurality of antennas; A channel estimator estimating a channel of the received subcarriers; A channel converter for changing a channel of subcarriers estimated by the channel estimator based on a power weight value assigned to each of the subcarriers; And a demodulator for detecting a signal based on a changed channel of the subcarriers and a demodulator for converting the subcarriers into an original data signal.

According to an embodiment of the present invention, a reception signal detection performance may be improved in a receiver using an OSIC scheme or an MMSE-OSIC scheme.

The present invention according to the embodiment can improve the reception signal detection performance for the MIMO reception signal.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable internet system, and more particularly, to a data transmission / reception method capable of improving signal detection performance and a base station supporting the same.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention. Prior to the description with reference to the drawings, the frame structure of the portable Internet system will be briefly described.

The portable Internet system uses a TDD scheme that separates downlink and uplink by time, and uses OFDMA as a multiple access scheme. An OFDMA symbol consists of a plurality of subcarriers. Multiple subcarrier types consist of data subcarriers, pilot subcarriers for various estimations, null subcarriers for guard bands, and DC subcarriers.

The frame consists of a downlink and an uplink subframe, and the first OFDMA symbol of the downlink (DL) subframe consists of a preamble period and the remaining OFDMA symbols consist of a data transmission period.

The data transmission section of the downlink subframe may be divided into a partial usage of sub channels (PUSC) section and an AMC section. The PUSC section can divide the entire frequency band into cluster units, the AMC section can divide the entire frequency band into bins, and the AMC subchannel consists of six adjacent bins in the same band.

The above-described PUSC, diversity and AMC intervals or zones may be determined by the base station according to channel distribution of the terminals. In addition, some OFDMA symbols located in the second half of the downlink subframe may be used for a broadcast service, and the same IDcell for the same subchannel configuration for each cell and the number of broadcast symbols is defined in DL_MAP_IE. In the uplink subframe, the PUSC section may divide the entire band by a tile unit, and six tiles constitute one slot.

The present invention relates to a data transmission / reception method and a device supporting the same in a portable Internet system that transmits and receives data using a MIMO method and detects a received signal using an OSIC method or an MMSE-OSIC method. .

Hereinafter, a case in which the transmitter 100 is included in the base station and the receiver 200 is included in the terminal based on a downlink for transmitting data from the base station to the terminal will be described as an example.

1 is a diagram illustrating a part of a downlink frame to which a data transmission method according to an embodiment of the present invention is applied, and FIG. 2 is a block diagram illustrating a transmitting device according to a first embodiment of the present invention.

As shown in FIG. 1, a downlink data region is divided into subcarriers of a predetermined unit in a frame transmitted to a terminal through a plurality of antennas and grouped, and the data signals (subcarriers) of groups transmitted to each antenna are grouped. It is intended to improve the performance of signal detection in the receiver by setting the power values symmetrically differently by ± α and transmitting.

Here, subcarriers of a certain unit grouped in the downlink region may be clusters as illustrated in FIG. 1. The cluster includes pilots for each antenna as well as the data signal.

The α value, which increases or decreases the power value of the data signals (+), may vary depending on the channel condition, and the average value of all data signals in the frame may be increased or decreased due to a power value having the same magnitude in one frame. There is no change in the power value.

To this end, the transmission device 100 according to the first embodiment of the present invention, as shown in Figure 2, the encoding unit 110, modulator 120, MIMO encoder 130, sub-channel mapping unit 140 , A power controller 150, a PRBS adder 160, and a transmitter 170.

The other components except for the power controller 150 in the configuration of the transmitter 100 are the same as those applied to a general transmitter that supports the MIMO scheme. Hereinafter, the power controller 150 will be described in detail. Other configurations will be briefly described.

First, the encoding unit 110 encodes input data into a transmission signal, and the modulation unit 120 modulates the encoded and input transmission signal according to a predetermined modulation scheme.

The MIMO encoder 130 encodes the transmission signal modulated by the modulator 120 to be transmitted through the MIMO scheme, and the subchannel mapping unit 140 finds a channel having optimal performance for each terminal and then optimizes the performance. The signals encoded in the MIMO scheme are mapped to the allocated subchannels such that radio resources are allocated to the terminal through the channel of the.

The power controller 150 maintains the average power value of the data signal of the entire frame at the original value, while transmitting a predetermined unit of data (subcarrier) signal transmitted through a plurality of antennas (eg, first and second antennas). Group them together. Here, the grouped data signals may be clustered, as shown in FIG. 1.

In addition, a power weight value (α) that is higher or lower from the original power value of the subcarrier signals for each cluster group of data signals, that is, for each cluster, is set symmetrically, as shown in Equation 1 below. The power values of the data signals grouped in the region are converted to be symmetrical by ± α.

,

,

In Equation 1, “S0” denotes an original data signal to be transmitted through a first antenna, and “S1” denotes an original data signal to be transmitted through a second antenna. In addition, "C" means "α" values assigned to the "S0" and "S1".

As shown in FIG. 1, a PUSC period in which 28 subcarriers (symbols) are distributed in all frequency bands in a downlink (DL) of a frame is taken as an example. Group the subcarriers in cluster units and increase or decrease (+ α, -α) power values of data transmitted by being divided through a plurality of antennas in grouped cluster units by α.

Specifically, the data signals of the first cluster (cluster 0) transmitted through the first antenna (Antenna 0) increase the power value by α from the original power value (+ α), and through the first antenna The data signals of the second cluster (cluster 1) to be transmitted lower the power value by α from the original power value (−α).

Referring to the reference of the first antenna and the subchannel axis, the power value of + α which is higher in the power values of the data signals of the first cluster and the power value of -α which is lowered in the power values of the data signals of the second cluster are shown. Are symmetrical to each other.

In addition, in order to be symmetrical with the first antenna (Antenna 0), that is, the power values by (−) α that are higher (+) or lower (−) in the power values of the data signals in the symbol direction are symmetric with each other. Data signals of the third cluster (cluster 2) transmitted through the antenna 1 lower the power value by α from the original power value (-α), and the fourth cluster (cluster 3) transmitted through the second antenna. Data signals increase the power value by α from the original power value (+ α).

Referring to the reference of the second antenna and the subchannel axis, the power value of -α lowered in the power values of the data signals of the third cluster and the power value of + α increased in power value of the data signals of the fourth cluster. Are symmetrical to each other.

Referring to clusters transmitted to the terminal through the first antenna and the second antenna on the symbol axis basis, power values of α are symmetrically increased in data signals of clusters transmitted through different antennas at the same time point ( +) To be lowered (-)

As described above, the power average value of α, in which a certain unit of subcarriers is raised or lowered in the power values of the data signals of the grouped clusters, is symmetric with each other, so that the overall average power value of the data signals in the frame is equal to the original signal power value. same.

As described above, the data signal whose power value is increased or decreased by α by the power controller 150 is changed to the PRBS adder 160.

Subsequently, the PRBS adder 160 adds a pseudo random binary sequence to the subcarrier signals in order to increase the interference and the channel estimation efficiency between the subcarrier signals from the power controller 150, and the transmitter 170. The subcarrier signals whose power value of the data is adjusted by the power controller 150 are converted into OFDM signals by performing inverse fast fourier transform (IFFT) operations for each transmitting antenna.

In addition, in order to prevent the occurrence of inter-channel interference that distorts the subcarrier, a CP (Cyclic Prefix) is inserted at a guard interval position and transmitted through each antenna. In this case, the information on the transmitted data burst is defined in the downlink and uplink map information elements DL_MAP_IE and UL_MAP_IE in the map message area.

The transmitter 100 may include a message generator (not shown) for generating DL_MAP_IE and UL_MAP_IE including information on the data burst to be transmitted, and the message generator may have a power value of ± α in the receiver described later. A data power control message is generated to recover the original data from the data signal that has been changed and received.

The data power control message is generated using the information on the value of α from the power controller 150, and the data power control message is transmitted from a transmitter (base station) and a receiver (terminal) at the initial network entry. It can be sent and received during the capability negotiation process, for example, can be sent and received through the SBC request message and SBC response message. In addition, when the α value needs to be changed in accordance with a change in the channel state between the transmitting apparatus (base station) and the receiving apparatus (terminal), it may be transmitted and received between the transmitting apparatus (base station) and the receiving apparatus (terminal) even during a communication service.

As described above, in the case of transmitting a data signal of a frame through a plurality of antennas in a downlink frame using the MIMO scheme, the present invention provides a cluster of data signals transmitted through each antenna, such as a cluster. Group by a certain unit. The power values of the data signals of each group are increased (+ α) or decreased (-α) by α so that the power values of the data signals of the neighboring groups are symmetrical. Then, the average value of the power value of the data signal in the transmission frame for each antenna or the total average value of the data signal power value in the transmission frame for each antenna at the same time is set to be equal to the original power value.

As described above, when the receiver receives the data signal having the changed power value, the difference in power value of the data signals becomes larger than the difference in power values of the original data signals when the data signal is detected using the OSIC scheme. Performance will be improved.

In the above description, a group of subcarriers in which power values of data signals are set differently is described as a cluster in the downlink, but this is one example of various embodiments implemented by the present invention.

According to another embodiment of the present invention, a predetermined unit for differently setting the power values of the data signals may be set to be small or empty or tones, and may be set by dividing the downlink frame in half. In addition, the α value applied to the power value may vary depending on the number of antennas and channel conditions formed in the transmitter and the receiver.

Next, a receiving apparatus according to a second embodiment of the present invention will be described with reference to FIG. 3.

The receiver 200 according to the second embodiment of the present invention illustrated in FIG. 3 includes a receiver 210, a PRBS remover 220, a subchannel demapper 230, a channel estimator 240, and a channel converter. A unit 250, a signal detector 260, and a demodulator 270, and a power value of ± α is changed from a transmitting apparatus (base station) to detect data signals received through a plurality of antennas, thereby recovering original data. Decrypt Here, the power value of the received data signals is changed by ± α, and there is no change in the average power value of all data signals in the frame.

First, the receiver 210 converts signals received through respective antennas into baseband signals. To this end, the receiver 210 removes a CP included in the received signal and converts an OFDM symbol of the received signal through a fast fourier transform (FFT) operation into a subcarrier-specific signal.

The PRBS removal unit 220 removes a pseudo random binary sequence included in the subcarrier signals in order to increase interference and channel estimation efficiency between the subcarrier signals.

The subchannel demapping unit 230 separates subcarriers mapped to the subchannels from each subchannel. The channel estimator 240 estimates a channel of the received subcarriers. Here, the channel estimation is performed using a predetermined signal, such as a pilot signal. Here, the subcarrier signal separated by the sub-channel demapping unit 230 and information about the channel estimated by the channel estimating unit 240 are provided to the channel converter 250.

Subsequently, the channel converter 250 restores the original data from the received data signal by increasing (+ α) or decreasing (-α) the power value of α from the transmitting apparatus (base station) through the downlink DL. To do this, the channel estimated by the received pilot signal is converted. Here, the estimated channel conversion is performed on the α value included in the transmission / reception data power control message during the capability negotiation process between the transmitter (base station) and the receiver (terminal) at the initial network entry. Based on the information.

As shown in FIG. 1, in a PUSC period of a downlink (DL) of a frame, power values of data signals grouped in cluster units are received through a first antenna and a second antenna with power values different by ± α. As an example, the channel conversion performed by the channel converter 250 will be described.

As described above, the power value of the data signal received through the downlink DL is changed by ± α from the power value of the original data signal in units of the cluster.

Data signals of the first cluster (Cluster 0) received through the first antenna (Antenna 0) of FIG. 3 are received by increasing the power value by α from the original power value (+ α), and receiving the second cluster (Cluster 1). ) Data signals are received by lowering the power value by α from the original power value (−α).

Referring to this, based on the first antenna and the subchannel axis, the data signals of the first cluster (Cluster 0) and the second cluster (Cluster 1) are symmetrically added (+) by the value of α from the original power value. It has a negative value.

The data signals of the third cluster (Cluster 2) received through the second antenna (Antenna 1) to be symmetrical with the first antenna (Antenna 0) is lowered by the power value of α by the original power value (- α) is received, and the data signals of the fourth cluster Cluster 3 are received by increasing the power value by α from the original power value (+ α).

Referring to the reference of the second antenna and the subchannel axis, the data signals of the third cluster 4 and the cluster 3 are symmetrically positive (−) with power values equal to α. Has the specified value.

Referring to the data signals of the clusters received through the first antenna and the second antenna with respect to the symbol axis, the data signals of the clusters received through the different antennas at the same time point have a symmetrical power value (+). ) That is, the power value of α is increased (+ α) in the power value of the data signals of the first cluster received through the first antenna, and α in the power value of the data signals of the third cluster received through the second antenna. Power value is lowered (-α). In addition, the power value of the data signals of the second cluster received through the first antenna is lowered by (−α) and the power value of the data signals of the fourth cluster received through the second antenna is lowered. The power value by α is increased (+ α).

As such, when the received data signals are increased (+) or decreased (−) from the original power value from the channel point of view, the received data signals are increased by increasing the power value by α. It can be seen that it was received through a better channel, and the power value by α was lowered so that the received data signals were received through a channel worse than the original channel.

As described above, the channel converter 250 restores the original data from the received data signal by increasing (+ α) or decreasing (-α) the power value by α, according to Equation 2 below. During initial network entry, the channel estimated by the pilot signal is converted on the basis of a predetermined ± α value in the capability negotiation process between the base station and the terminal.

That is, the power value of α is increased to convert the channel of the data signals of the received cluster into a second channel which is better than the estimated first channel, and the power value of α is lowered so that the channel of the data signals of the cluster is received. Convert to a fourth channel inferior to the estimated third channel. Here, the channel converted from the estimated channel is based on the value of α.

Then, the original data is recovered from the received data signal using the converted channel. Here, if the value of α is set to 0, data is restored using a general decoding method.

Even when the transmitter 100 transmits the data signal with the same power value, the gain of the data signal received by the receiver 200 varies according to the channel environment. The present invention according to the embodiment is intended to apply that the gain of the received data signal varies depending on the channel environment in the process of restoring the original data from the received data signal.

Specifically, in terms of the channel environment, data signals having a power value as high as (+ α) are obtained in the same manner as receiving data signals through a channel having a better environment than the original channel. In addition, in view of the channel environment, data signals with a power value lowered by α (−α) are obtained in the same manner as receiving data signals through a channel having a worse environment than the original channel.

In the channel converter 250 of the receiver 200 according to the second embodiment of the present invention, data signals whose power value is increased by α from the power value of the original data signal are compared to the original channel according to the set + α value. Change the channel settings to those received on the good channel.

The data signals whose α values are lowered to the original data signals are changed through the channels worse than the original channels according to the set −α value. After the estimated channel change, the process performed in the transmission path is reversed based on the changed channel to recover original data from the received data signals. The MMSE-OSIC detector 260 detects an original signal transmitted from the transmitter 100 using the received signal and the channel value of the signal. The demodulator 270 demodulates the original signal from the signal detected by the MMSE-OSIC detector 260.

As described above, when data signals in which the power value of the signal is changed by reflecting a power value of ± α from the power value of the original data signal in cluster units are received, a signal among a plurality of data signals received through the OSIC method By selecting and detecting the data signals in ascending order of power values (intensities), interference between the plurality of received signals is reduced. Here, the hard decision method and the soft decision method may be used for signal detection.

In the above-described embodiment, a case in which the transmitting apparatus 100 is included in the base station and the receiving apparatus 200 is included in the terminal based on a downlink (DL) for transmitting data from the base station to the terminal is taken as an example. In the exemplary embodiment of the present invention, when the terminal is an uplink (UL) for transmitting data to the base station, the transmitting device 100 may be included in the terminal, and the receiving device 200 may be included in the base station.

Referring to FIG. 4, an uplink subframe generated by the transmitter 100 when the terminal transmits data to the base station will be described.

As shown in FIG. 4, the transmitting apparatus 100 includes a predetermined number of tiles (for example, 3) consisting of two pilot subcarriers and eight data signals (subcarriers) in a PUSC section of an uplink (UL) of a frame. Tiles) are grouped, and a value of α is added or subtracted (+ α, −α) to the power value of the data signal in units of tile groups. That is, the power values of the data signals are changed to have different power values as much as ± α between the tile groups and transmitted to the base station through the first antenna and the second antenna.

The power value of the data signal transmitted through the uplink (UL) is changed by a power value of ± α from the power value of the original data signal in the tile group unit (for example, 1/2 slot). Here, when three tiles are configured as one tile group in the uplink, since six tiles constitute one slot, each tile group is 1/2 slot.

In detail, data signals of the first tile group (tile group 0) corresponding to the 1/2 slots transmitted through the first antenna (Antenna 0) are increased as much as α from the original power value (+ α) transmitted, and the data signals of the second tile group (tile group 1) transmitted through the first antenna are transmitted with the power value lowered by α from the original power value (−α).

Referring to this, based on the first antenna and the subchannel axis, the power values of the data signals of the first tile group and the second tile group are symmetrically increased (+) or decreased by (+) from the original power value ( -) Has a value.

In addition, the data signals of the third tile group (1/2 slot, tile group 2) transmitted through the second antenna (Antenna 1) to be symmetrical with the first antenna (Antenna 0) are equal to α in the original power value. The data values of the fourth tile group (1/2 slot, tile group 3) transmitted by lowering the power value (-α) and transmitted through the second antenna are increased by the power value by α from the original power value ( + α) is transmitted.

As a reference to the second antenna and the subchannel axis, the data signals of the third tile group and the fourth tile group have values of symmetrically high (+) or low (-) power values of α.

Referring to the data signals of the tile groups transmitted from the first antenna and the second antenna on the symbol axis basis, the data signals of the tile groups transmitted through the different antennas at the same point in time have a symmetrical power value of α. It is either (+) or down (-).

 That is, the power value of the data signals of the first tile group transmitted through the first antenna is as high as (+ α) and the power value of the data signals of the third tile group transmitted through the second antenna. Has lowered the power value by α (−α).

In addition, the power value of the data signals of the second tile group transmitted through the first antenna is lowered by the power value by α (−α), and the power of the data signals of the fourth tile group transmitted through the second antenna. The value is as high as (α) the power value.

As described above, the transmitting apparatus 100 of the present invention changes the power value by ± α from the power value of the original data signal in a tile group unit (for example, 1/2 slot) composed of a predetermined number of tiles. Send data signals.

Here, the average value of the power value of the data signal transmitted for each antenna or the total average value of the data signal power value transmitted for each antenna at the same time is set to be equal to the original power value.

In the receiving apparatus 200 according to an embodiment of the present disclosure, as described above, the data signal is selected from the plurality of data signals received through the OSIC scheme in order of increasing power value (strength). The detection reduces the interference between the plurality of received signals.

In the above description, a predetermined unit for setting the power values of the data signals differently is described as being 1/2 slot in the uplink, but this is one example of various embodiments implemented through the present invention.

According to another embodiment of the present invention, a predetermined unit for differently setting the power values of the data signals may be set to be small or empty or tones, and may be set by dividing the uplink frame in half. In addition, the α value applied to the power value may vary depending on the number of antennas and channel conditions formed in the transmitter and the receiver.

5 is a flowchart illustrating a data transmission method according to an embodiment of the present invention.

The data transmission method illustrated in FIG. 5 illustrates an example in which a transmitting unit (base station) transmits data to a receiving unit (terminal) through a downlink, and the roles of the transmitting unit and the receiving unit are switched so that the terminal transmits to the base station through the uplink. The same applies to the case of transmitting data. In the following description, a base station is defined as a transmitter and a terminal is defined as a receiver.

Referring to FIG. 5, when a base station (transmitter) intends to transmit data to a terminal (receiver), it checks whether it is an initial transmission (S100).

As a result of S100, if it is the initial transmission, in order to transmit data to the terminal, that is, to provide a communication service to the terminal, a network topology advertisement process, a MSS scanning of neighbor BS, and an association process are performed. Initial network entry procedure including procedures) is performed (S110).

Together with S110, an α value for changing a power value of data signals configured in a predetermined unit in a frame is set (S120). Here, the α value may vary depending on the channel state. For example, when the channel state of the data signals transmitted through the first antenna and the channel state of the data signals transmitted through the second antenna are the same or similar, it may be difficult to determine the superiority of the signal received by the terminal. The α value is set to the first value. On the other hand, when the channel state of the data signals transmitted through the first antenna and the channel state of the data signals transmitted through the second antenna is different, even if the α value is small, it is not difficult to determine the superiority of the signal received by the terminal. At this time, the α value is set to a second value smaller than the first value.

Thereafter, a range of subcarriers to which the α value is applied, that is, a predetermined unit of data signals is set (S130). Here, the predetermined unit of the data signals (subcarriers) means a range of the data signal group to which the α value is applied, and may be set to, for example, 1/2 slot and a cluster (symbol).

The base station sets and transmits power values of neighboring data signal groups differently according to a predetermined unit and a value of α. As described above, when the power values of the neighboring data signal groups are differently set and transmitted, it is easy for the terminal which detects the received data signal based on the OSIC scheme to determine the superiority of the power values of the received signals. The performance of signal detection is improved.

In the above description of S120 and S130, after setting the α value, the unit of the subcarrier to which the α value is applied is set. However, this is an embodiment, and the unit of the subcarrier to which the α value is applied is set first. The α value can be set later.

Thereafter, the power values of the data signals are adjusted differently according to a predetermined value (data signal group) of the α value set in S120 and the subcarrier set in S130 (S140).

In step S100, if the transmission result is not the initial transmission, the power value of the data signal is adjusted by differently setting the power values of the data signals for each group of the α value and the subcarrier set in the previous transmission step (S140).

After the step S140, the value of α is applied to each group to modulate the data transmission signals whose power values are adjusted to band signals (S150), and the modulated transmission signals are transmitted to the terminal through a plurality of antennas by applying a MIMO scheme. (S160).

As described above, since the α value can be changed according to the channel state, after the data signal is transmitted by applying the α value in S160, the α value is changed using the pilot signal received through the uplink. Check whether there is (S170).

As a result of checking in S170, if there is no change in the channel state, the α value set in S120 is maintained (S180). On the other hand, as a result of the check in S170, if there is a change in the channel state, it is checked whether the α value should be reset (S190).

As a result of checking in S190, when the channel state confirmed through the pilot signal is greatly changed in the case of the previous transmission and the reset of the α value is required, the α value is reset based on the changed channel state (S200). Here, when the value of α is reset, although not shown in FIG. 5, a procedure for transmitting and receiving between the base station and the terminal is performed by including information on the reset value α in the data power control message.

On the other hand, as a result of confirming in S190, when the channel state confirmed through the pilot signal has changed in the case of the previous transmission, but the degree of change is so small that resetting of the α value is not required, the α value set in S120 is maintained ( S180).

In the data transmission method according to an embodiment of the present invention, the power values of the data signals may be set differently for each group consisting of a certain number of data signals in a frame transmitted to the terminal (receiver) through the above-described process. have. Through this, it is possible to improve the performance of signal detection when detecting the received signal using the OSIC method and the MMSE-OSIC method.

6 is a flowchart illustrating a data receiving method according to an embodiment of the present invention.

6 shows an example of a data receiving method of detecting a data signal by receiving the data from the base station when the terminal transmits data to the base station through the uplink, and the roles of the transmitting unit and the receiving unit are switched. The same applies to the case of detecting a data signal received through the downlink.

Referring to FIG. 6, a data signal transmitted from a terminal through an uplink is received through a plurality of antennas (S210). Here, the transmission and reception of data signals between the base station and the terminal uses a MIMO scheme.

After reception of the data signal, it is checked whether the α value set between the base station and the terminal is “0” (S220). Here, the α value is added to or decreased from the power value of the original data signal so that the power value of the plurality of data signals is large and small, that is, the superiority between the data signals can be easily detected when the received data signal is detected by applying the OSIC scheme. Rejection means the power value. The α value is set between the base station and the terminal during the initial network entry process, and the value may vary depending on the channel state.

As a result of checking in S220, if the value of α is “0”, since the received data signal is transmitted using a general MIMO method, the received data signal is detected using the MMSE method (S270). Thereafter, original data is restored from the data signal detected in S270 by using a hard decision method and a soft decision method (S260).

On the other hand, as a result of checking in S220, if the value of α is not “0”, it means that the power value of the data signals received from the terminal is changed by the value of α from the original value. In this case, the signal detection performance may be improved when the OSIC method of detecting a signal by determining a superior right in power values of the plurality of received data signals.

Thereafter, in order to detect the data signals received through the plurality of antennas by using the OSIC scheme and restore the original data, the signals received through the plurality of antennas are separated (S230).

Thereafter, the OSIC method is applied to remove signals sequentially detected according to the strength of the data signal to reduce the influence of interference between the received signals. That is, a signal having a large intensity is first selected and detected according to the superiority of the plurality of separated signals, and then a signal having a small intensity is selected and detected.

Thereafter, the channel is changed according to the α value set to restore the original data from the data signal whose power value is changed by the α value (S240).

Specifically, since the terminal (transmitter) increased (+ α) or lowered (-α) the power value by the α value to the signal power values of the subcarriers grouped as 1/2 slots, the power value by α In order to restore these changed data signals to original data, the power value by α must be lowered (-α) or increased (+ α).

 To this end, the channel of the data signal estimated from the received pilot signal is changed according to the α value. That is, the channel of the data signals whose value is increased by + α to the original data signal is changed to a better channel than the estimated channel, and the channel of the data signals whose value is lowered by -α to the original data signal is worse than the estimated channel. Change to the channel.

As described above, when the power value of α is increased or decreased in the original data signal, the difference in the power values of the received data signals is turned on than in the general method, so that the superiority of the data signals can be easily determined. It becomes possible.

Since the OSIC method sequentially removes the detected signals according to the strength of the detected signals to reduce the influence of interference between the received signals, the signal detection performance is increased when the value of the received signals is large.

After S240, a signal received through a plurality of antennas through a MMSE-OSIC method based on the changed channel and the received data signal is used to perform a signal using a hard decision method and a soft decision method. In operation S250, original data is restored from the detected signal in operation S260.

Configuration and operation as described above is not limited to the claims of the present invention as an embodiment, and various changes and modifications are possible within the scope of not changing the technical spirit of the present invention in the field to which the present invention belongs. It is obvious to those who are engaged.

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

1 is a view showing a portion of a downlink frame to which a data transmission and reception method according to an embodiment of the present invention is applied.

2 is a block diagram illustrating a transmitting device according to a first embodiment of the present invention.

3 is a block diagram illustrating a receiving apparatus according to a second exemplary embodiment of the present invention.

4 is a diagram illustrating a portion of an uplink frame to which a data transmission and reception method according to an embodiment of the present invention is applied.

5 is a flowchart illustrating a data transmission method according to embodiments of the present invention.

6 is a flowchart illustrating a data receiving method according to embodiments of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: transmitter 110: encoding unit

120: modulator 130: MIMO encoder

140: subchannel mapping unit 150: power controller

160: PRBS adding unit 170: transmitting unit

200: receiver 210: receiver

220: PRBS removal unit 230: subchannel demapping unit

240: channel estimator 250: channel converter

260: signal detector 270: demodulator

Claims (31)

In the data transmission method of the portable Internet system, Defining a power weight value for raising or lowering a power value of an original subcarrier signal based on a channel state at initial network entry and subcarrier groups to which the power weight value is applied; A positive power weight value is assigned to subcarriers of a first subcarrier group among the subcarrier groups, and the positive power weight value is assigned to subcarriers of a second subcarrier group neighboring the first subcarrier group. Assigning a negative power weight value that is symmetrical with; And And modulating the subcarriers to which the power weight value is applied into a transmission signal and transmitting the modulated subcarriers to a receiver through a plurality of antennas. The method of claim 1, And resetting the power weight value based on the changed channel state when the channel state is changed. The method of claim 1, And the first subcarrier group and the second subcarrier group are transmitted to the receiver through the same antenna. The method of claim 1, And the first subcarrier group and the second subcarrier group are transmitted to the receiver through different antennas. The method of claim 1, And setting the average power value of the subcarriers to which the power weight value is applied to be equal to the average power value of the original subcarrier signals and transmitting the same to the receiver. The method of claim 1, The subcarrier group to which the power weight value is applied comprises at least one subcarrier and subcarriers corresponding to 1/2 of the maximum total subframe. The method of claim 1, A positive power weight value is assigned to subcarriers of the first subcarrier group based on a subchannel axis of a frame, and the positive power is assigned to subcarriers of a second subcarrier group neighboring the first subcarrier group. And a negative power weight value symmetric to the weight value and transmitted to the terminal. The method of claim 1, A positive power weight value is assigned to subcarriers of the first subcarrier group based on a symbol axis of a frame, and the positive power weight is assigned to subcarriers of a second subcarrier group neighboring the first subcarrier group. And transmitting a negative power weight value symmetric to the value to the terminal. The method of claim 1, The power weight value has a different value according to a change in channel state. The method of claim 1, The power weight value is set to a first value when the channel states of the first and second subcarrier groups are the same, and the power weight value is set when the channel states of the first and second subcarrier groups are different. And transmitting the subcarriers to the terminal by setting the second value smaller than the first value. In the data receiving method of the portable Internet system, Receiving a message including information on a power weight value for raising or lowering a power value of an original subcarrier signal based on a channel state at an initial network entry; Receiving subcarriers through a plurality of antennas to which a power weight value for increasing or decreasing a power value of an original subcarrier signal is added for each group of subcarriers; Detecting the received subcarriers using a signal detection scheme based on a difference in power values of the subcarriers; Maintaining or changing an estimated channel of received subcarriers based on a power weight value assigned to each of the subcarrier groups; And Restoring the detected subcarriers to original data based on the changed channel. When the estimated channel of the subcarriers is changed, the power value of α is increased to convert the channel of the data signals of the received cluster into a second channel that is better than the estimated first channel, and the power value of α is lowered. And converting the channel of the data signals of the cluster into a fourth channel that is worse than the estimated third channel. The method of claim 11, And maintaining the estimated channel and restoring original data from the received subcarriers using the MMSE scheme when the power weight value is "0". The method of claim 11, When the power weight value is not "0", the estimated channel is changed and original data is recovered from the received subcarriers using an OSIC scheme or a signal detection scheme including the OSIC scheme. How to receive data. The method of claim 11, Changing the channel of the subcarriers, And if the power weight value is a positive value, change a channel of subcarriers to a channel having a higher level than the estimated channel. The method of claim 11, Changing the channel of the subcarriers, And when the power weight value is negative, changing the channel of subcarriers to a channel having a lower level than the estimated channel. The method of claim 11, The signal detection method is an OSIC method or an MMSE-OSIC method. The method of claim 11, Before receiving the subcarriers to which the power weight value has been added through a plurality of antennas, Receiving a message comprising information on the power weight value. delete delete delete delete In the transmitter of the portable Internet system using the MIMO system, A MIMO encoder for encoding the input data signal to be suitable for the MIMO scheme; A sub channel mapping unit for mapping the data signal from the MIMO encoder to a sub channel; Set a power weight to change the power value of the data signal based on the subchannel, give a positive power weight value to the subcarriers of the first subcarrier group from among a plurality of subcarrier groups, and the first sub A power controller for giving subcarriers of a second subcarrier group adjacent to the carrier group to a negative power weight value symmetrical with the positive power weight value; A signal processor converting the power weighted subcarriers into a band signal; And And a transmitter for transmitting the band signal from the signal processor through a plurality of antennas. The method of claim 22, And transmitting the first subcarrier group and the second subcarrier group to which the power weight value is assigned through the same antenna. The method of claim 22, And transmitting the first subcarrier group and the second subcarrier group to which the power weight value is assigned through different antennas. The method of claim 22, And transmitting the average power value of the subcarriers to which the power weight value is assigned to be equal to the average power value of the original subcarrier signals. The method of claim 22, A positive power weight value is assigned to subcarriers of the first subcarrier group based on a subchannel axis of a frame, and the positive power is assigned to subcarriers of a second subcarrier group neighboring the first subcarrier group. And a negative power weight value symmetric to the weight value and transmitted. The method of claim 22, A positive power weight value is assigned to subcarriers of the first subcarrier group based on a symbol axis of a frame, and the positive power weight is assigned to subcarriers of a second subcarrier group neighboring the first subcarrier group. And a negative power weight value that is symmetric to the value and transmitted. delete delete delete delete

Images