WO2009145549A2

WO2009145549A2 - Apparatus for transmitting and receiving a signal and a method thereof

Info

Publication number: WO2009145549A2
Application number: PCT/KR2009/002785
Authority: WO
Inventors: Sang Chul Moon; Woo Suk Ko
Original assignee: Lg Electronics Inc.
Priority date: 2008-05-27
Filing date: 2009-05-26
Publication date: 2009-12-03
Also published as: EP2286531A2; WO2009145549A3; EP2286531A4

Abstract

In one aspect of the present invention, a method for receiving a signal is disclosed. The method includes demodulating (S210)signals being received to multiple antennas, respectively; parsing (S220) signal frames of the demodulated signals in transmission paths, respectively; performing (S230) MIMO decoding on signals in the signal frames based upon a correlation between channels of the signals being received to the multiple antennas to output MIMO-decoded symbols to multiple paths or a single path in accordance with the correlation; symbol-demapping (S240) the MIMO-decoded symbols to symbol-demapped data in accordance with the correlation, wherein the MIMO-decoded symbols in the multiple paths are symbol-demapped respectively and the respective symbol-demapped data are multiplexed, or the MIMO-decoded symbols in the single path are symbol-demapped together to symbol-demapped data; outputting (S250) bit data using at least one of the multiplexed symbol-demapped data and the symbol-demapped data in the single path; and error correction decoding (S260)the outputted bit data.

Description

APPARATUS FOR TRANSMITTING AND RECEIVING A SIGNAL AND A METHOD THEREOF

The present invention relates to an apparatus for transmitting and receiving a signal and a method thereof that may enhance data transmission efficiency.

In order to enhance data transmission efficiency in broadcasting and telecommunication systems, interest in methods of using two or more transmitting and receiving antennas is growing. As one of the methods of using two or more transmitting and receiving antennas, the multi-input multi-output (MIMO) technology has already been adopted in telecommunication systems such as wireless broadband (Wibro) systems or 3rd generation partnership project (3GPP) systems. The MIMO technology broadlyconsists of spatial diversity, which reduces the transmission error rateso as to enhance the transmission efficiency, and spatial multiplexing, which transmits different data types from multiple antennas so as to enhance the transmission rate. It is also highly likely that the above-described MIMO technology will be adopted as the transmission method for the next generation digital broadcasting.

An object of the present invention devised to solve the problem lies on proposing an apparatus and method for transmitting and receiving signals that can enhance data transmission efficiency.

An object of the present invention devised to solve the problem lies on proposing an apparatus and method for transmitting and receiving signals that can enhance transmission efficiency of digital broadcast data by using the MIMO technology.

A further object of the present invention devised to solve the problem lies on proposing an apparatus and method for transmitting and receiving signals that can enhance transmission efficiency of digital broadcast data even in a channel condition unsuitable for the MIMO technology.

To achieve the objects, methods for transmitting and receiving a signal in claims 1 and 3 are disclosed. The symbol-mapping may vary depending upon the number of transmission paths.

In another aspect, devices for transmitting and receiving a signal in claims 6 and 8 are disclosed.

The plurality of symbol mappers (330a, 330b) is further configured to symbol-map the demultiplexed bits in accordance with different symbol mapping methods.

The present invention is advantageous in that by using the MIMO technology the transmission efficiency of digital broadcast data may be enhanced, and that a signal transmission robust against errors may be provided. Furthermore, the digital broadcast data can be transmitted or received by using the MIMO technology even in a channel condition unsuitable for the MIMO technology.

FIG. 1 illustrates an exemplary transmitting system adopting the MIMO technology.

FIG. 2 illustrates an apparatus for receiving a signal according to an embodiment of the present invention.

FIG. 3 illustrates an apparatus for transmitting a signal according to another embodiment of the present invention.

FIG. 4 illustrates an apparatus for receiving a signal according to another embodiment of the present invention.

FIG. 5 illustrates an exemplary constellation based upon an antenna path.

FIG. 6 illustrates an exemplary constellation of received signals, when a channel correlation between each of the antenna paths is high.

FIG. 7 illustrates a method for transmitting a signal according to an embodiment of the present invention.

FIG. 8 illustrates a method for receiving a signal according to an embodiment of the present invention.

The possibility of adopting the multi-input multi-output (MIMO) technology, as a method of enhancing data transmission efficiency by using two or more transmitting and receiving antennas, also in digital broadcasting system is being researched.

The performance of a system adopting the MIMO technology relies on the characteristics of a transmission channel. Most particularly, the efficiency is more enhanced in systems having independent channel environments. In other words, if each of the channels from the transmitting end to the receiving end is independent from one another without having any correlation between one another, the performance of the system adopting the MIMO technology becomes greater. In a channel environment having a high cross-correlation between the transmission channels, such as a line-of-sight (LOS) environment, the performance of the system adopting the MIMO technology may show a sudden drop, or the system itself may fail to operate.

Generally, in a telecommunication system, such as a wireless broadband (Wibro) systems or 3rd generation partnership project (3GPP) systems, a two-way communication between a transmitting base station and a user terminal may be available. In the telecommunication system, the transmitting base station or the user terminal consistently monitors channel status with respect to a down-link from the base station to the user terminal and an up-link from the user terminal to the base station. Additionally, when the base station receives up-link information and detects a channel environment unsuitable for the MIMO technology, such as the LOS environment, the base station may transmit the information without adopting the MIMO technology. However, in a broadcasting system that does not include any up-link from the user terminal to the base station, such as a telecommunication system, the signal transmission technology cannot be adaptively modified based upon the channel monitoring result.

FIG. 1 illustrates an exemplary transmitting system adopting the MIMO technology. The disclosed embodiment of the transmitting system includes anerror correction encoding unit 110, a symbol mapper 120, an MIMO encoder 130, a first frame mapper 140a, a second frame mapper 140b, a first modulator 150a, and a second modulator 150b.

The error correction encoding unit 110 may error correction encode the data that are to be transmitted in appropriate units. The error correction encoding unit 110 adds redundancy data so that the data that are to be transmitted can become robust against errors and, then, performs the error correction encoding process.

The symbol mapper 120 maps the error correction encoded data to symbols. For example, the error correction encoded bit data, may be mapped into symbols based upon a specific symbol-mapping method, such as quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), and pulse amplitude modulation (PAM).

The MIMO encoder 130 distributes the mapped symbols to multiple antenna paths by using the MIMO technique. The MIMO encoder 130 distributes the inputted symbols to multiple transmission streams, so that the inputted symbols can be transmitted to each antenna path. In the example shown in this embodiment, the MIMO encoder 130 enables the data to be transmitted to two antenna paths.

The first frame mapper 140a and the second frame mapper 140b may map each transmission stream, which is to be transmitted to the respective antenna path, to a signal frame. The structure of the signal frame may vary depending upon the system to which the signal frame is to be transmitted. Therefore, an example of a specific signal frame structure will not be given herein.

The signal frame may be transmitted by being allocated to a single carrier or multiple carriers. Herein, an example of transmitting the signal frame by allocating the signal frame to multiple carriers will be described.

The first modulator 150a and the second modulator 150b respectively modulate the signal frame by using orthogonal frequency divisional modulation (OFDM). Thereafter, the first modulator 150a and the second modulator 150b may respectively transmit the modulated signal through each antenna.

FIG. 2 illustrates an apparatus for receiving a signal according to an embodiment of the present invention. The apparatus for receiving a signal according to the embodiment of the present invention includes a first synchronization unit (Sync) 210a, a second synchronization unit (Sync) 210b,a first demodulator 220a, a second demodulator 220b, a first frame parser 230a, a second frame parser 230b, a MIMO decoder 240, a symbol demapper 250, and an error correction decoding unit 260. The apparatus for receiving a signal according to the embodiment of the present invention may receive signals from multiple antennas based upon the MIMO technique. This embodiment shows an example of receiving the signals through two antennas so that the signal transmitted from the embodiment of the FIG. 1 can be received.

The first synchronization unit (Sync) 210a and the second synchronization unit (Sync) 210b respectively acquire synchronization from the signal received through each antenna. The first synchronization unit 210a and the second synchronization unit 210b may respectively acquire and output time synchronization and frequency synchronization of the received signal.

The first demodulator 220a and the second demodulator 220b respectively perform demodulation of the synchronized signal. Herein, the demodulation method may be in accordance with the modulation method. In the example according to the embodiment of the present invention, the demodulation process may be performed by using the OFDM method with respect to the embodiment shown in FIG. 1. Furthermore, the first demodulator 220a and the second demodulator 220b may respectively equalize the channels of the signals received through two antenna paths.

The first frame parser 230a and the second frame parser 230b respectively parse the frames of the signals equalized through the corresponding antenna paths.

The MIMO decoder 240 performs MIMO decoding on the signals parsed by the first frame parser 230a and the second frame parser 230b, respectively. The MIMO decoder 240 may output a symbol sequence as a result of the decoding

The symbol demapper 250 symbol demaps the symbols included in the receiving stream into a bit stream by using the symbol demapping method.

The error correction decoding unit 260 error correction decodes the demapped bit stream, thereby acquiring the transmitted data.

Each of the signals transmitted from multiple antennas of the apparatus for transmitting a signal to multiple antennas of the apparatus for receiving a signal may go through completely different channels or may be transmitted through the same or similar channels. If the signals transmitted to multiple channels using the MIMO techniquego through the same or almost identical channels, the correlation between each channel may become very high, thereby causing the apparatus for receiving a signal to be unable to separate the received signals. For example, signals that are transmitted through channels having high correlation between one another may not be processed with MIMO decoding by the MIMO decoder of the apparatus for receiving a signal. Therefore, even if the MIMO technique is adopted in order to enhance the data transmission efficiency, the performance of the apparatus may drastically become deficient depending upon the receiving environment. Hereinafter, however, an example of the apparatus for receiving a signal adaptively acquiring the corresponding signal, even if the channel status is as described above, will be disclosed as follows.

FIG. 3 illustratesan apparatus for transmitting a signal according to another embodiment of the present invention.The disclosed apparatus for transmitting a signal according to this embodiment includes an error correction encoding unit 310, a demultiplexer 320, a first symbol mapper 330a, a second symbol mapper 330b, a MIMO encoder 340, a first frame mapper 350a, a second frame mapper 350b, a first modulator 360a, and a second modulator 360b.

The error correction encoding unit 310 performs error correction encoding on the data that are to be transmitted in accordance with a specific error correction encoding method.

The demultiplexer 320 divides the error correction encoded data into streams so that each data stream can be outputted to a respective antenna path. For example, the demultiplexer 320 may demultiplex the data into a most significant bit (MSB) and a least significant bit (LSB) of data bits that are to be symbol-mapped to the first symbol mapper 330a and the second symbol mapper 330b. When (M+N) bits of data are transmitted through two antennas simultaneously, M bits of MSB data may be symbol-mapped in the first symbol mapper 330a and N bits of LSB data may be symbol-mapped in the second mapper 330b

The first symbol mapper 330a and the second symbol mapper 330b maps the streams that are to be transmitted to transmission antenna paths into symbols. The first symbol mapper 330a and the second symbol mapper 330b may also map bit streams that are to be transmitted to different constellations into symbols. For example, the first symbol mapper 330a may map the MSB, and the second symbol mapper 330b may map the LSB. The symbol-mapping method for each of the first symbol mapper 330a and the second symbol mapper 330b may be different from one another. For example, the first symbol mapper 330a may perform symbol-mapping according to a 64QAM method, and the second symbol mapper 330b may perform symbol-mapping according to a QPSK method. A detailed example will be presented with reference to FIG. 5.

When the data are transmitted as described above, and when it is assumed that a data size of (M+N) bps/Hz is simultaneously transmitted through two antennas, the first symbol mapper 330a maps a data size of M bps/Hz, and the second symbol mapper 330b maps a data size of N bps/Hz.

The MIMO encoder 340 receives the hierarchically symbol-mapped symbols as described above and, then, MIMO encodes the received symbols so that the received symbols are transmitted to respective antenna paths. For example, the MIMO encoder 340 distributes the symbols received by using a specific MIMO encoding method to the respective antenna paths, so that the antenna can perform transmission at an equal power.

The first frame mapper 350a and the second frame mapper 350b respectively configure respective signal frames that are to be transmitted to the respective antennas.

Finally, the first modulator 360a and the second modulator 360b respectively modulate the signal frames by using an orthogonal frequency divisional modulation (OFDM) method, thereby being able to transmitted the modulated signals to the respective antennas.

FIG. 4 illustrates an apparatus for receiving a signal according to another embodiment of the present invention. The apparatus for receiving a signal according to this embodiment of the present invention includes a first synchronization unit (Sync) 410a, a second synchronization unit (Sync) 410b, a first demodulator 420a, a second demodulator 420b, a first frame parser 430a, a second frame parser 430b, a MIMO decoder 440, a first symbol demapper 450a, a second symbol demapper 450b, a third symbol demapper 460, a multiplexer 470, a data merger 480, and an error correction decoding unit 490. The disclosed apparatus for receiving a signal according to this embodiment uses the MIMO technique so as to divide the signals received through multiple antennas into hierarchically symbol-mapped symbols based upon the corresponding channel condition. This embodiment shows an example of receiving signals transmitted through two antennas according to the embodiment shown in FIG. 3.

The first synchronization unit (Sync) 410a and the second synchronization unit (Sync) 410b acquire synchronization in the time and frequency domains of the signals received from the respective antennas.

The first demodulator 420a and the second demodulator 420 brespectively perform demodulation using the OFDM method on the synchronization-acquired signals. Also, channel equalization may be performed on the signals received through two antenna paths. During the channel-equalization process, the first demodulator 420a and the second demodulator 420b may respectively obtain channel information required for acquiring correlation between the channels through the antenna paths. For example, the first demodulator 420a and the second demodulator 420b may calculate (or compute) channel information from the signals through each of the two antenna paths by using a pilot signals.

The first frame parser 430a and the second frame parser 430b respectively parse signal frames from the signals equalized with respect to the two antenna paths.

The MIMO decoder 440 calculates channel correlation by using the channel information and performs MIMO decoding of the signals included in the parsed signal frames based upon the calculated channel correlation. The channel correlation information may be identified (or distinguished) based upon a predetermined reference standard by using the channel information obtained from each channel. However, this may vary depending upon the setting made by the system designer. Therefore, a detailed embodiment will not be disclosed in the description of the present invention.For example, when the MIMO decoder 440 determines that the channel correlation is low based upon the predetermined standard, the MIMO decoder 440 performs MIMO decoding on the signals transmitted from each antenna path. More specifically, when the MIMO Decoder 440 performs MIMO decoding, the inter-mixed signals may be separated from one another, thereby being outputted.

Conversely, when the MIMO decoder 440 determines that the channel correlation is high, the signals transmitted through each antenna path may be outputted as a single signal without being separated. Hereinafter, the process of performing MIMO decoding based upon the channel information in accordance with the above-described channel correlation will be referred to as a hierarchical MIMO technique. The MIMO decoder 440 may output a control signal, which can decide whether or not hierarchical demodulation is to be applied in accordance with the channel correlation calculated based upon the channel information.

The first symbol demapper 450a,the second symbol demapper 450b, and the third symbol demapper 460 respectively symbol-demap the hierarchical demodulation performed on the signals separated by the MIMO decoder 440 based upon the outputted control signalor performs symbol-demapping by using a single demodulation method.

For example, when the channel correlation is low, each of the first symbol demapper 450a and the second symbol demapper 450b receives the symbol separated and outputted by the MIMO decoder 440, and then each of the first symbol demapper 450a and the second symbol demapper 450b symbol-demaps the received symbol in accordance with each of the symbol-mapping methods. For example, when the symbols symbol-mapped based upon the hierarchical modulation shown in the example of FIG. 3 are separated, the first symbol demapper 450a symbol-demaps the received symbol by using the 64QAM method, and the second symbol demapper 450b symbol-demaps the received symbol by using the QPSK method. Since the first symbol demapper 450a and the second symbol demapper 450b can respectively receive the symbols separated by the MIMO decoder 440, the first symbol demapper 450a and the second symbol demapper 450b may each perform a symbol-demapping process, thereby outputting the bit stream corresponding to the MSB and the LSB of the receiving data.

In another example, when the channel correlation is high, the MIMO decoder 440 is unable to separate the signals transmitted through the antenna paths by using the MIMO technique. In this case, the MIMO decoder 440 may use a combined signal consisting of each of the received signals so as to perform symbol-demapping. The third symbol demapper 460 performs symbol-demapping on the symbol of the signal consisting of a combination of the signals transmitted through the antenna paths. In accordance with the above-described example, when a 64QAM symbol is received through the first antenna path, and when a QPSK symbol is received through the second antenna path, and when the two symbols cannot be separated, the symbols look like a symbol mapped based upon a 256QAM symbol-mapping method. Therefore, the third symbol demapper 460 performs symbol-demapping on the 256QAM symbol.

The multiplexer 470 may multiplex bit streams respectively symbol-demapped by the first symbol demapper 450a and the second symbol demapper 450b. According to the above-described example, the first symbol demapper 450a outputs the data corresponding to the MSB, and the second symbol demapper 450b outputs the data corresponding to the LSB. Herein, the symbol-demapping result may be multiplexed so that a single bit stream information (for example, a LLR value) is outputted.

The data merger 480 receives channel information from the MIMO decoder 440 based upon the channel correlation. Then, the data merger 480 selectively outputs the bits stream outputted from the multiplexer 470 or the third symbol demapper 460based upon the received channel information. Alternatively, the data merger 480 determines the bits stream using the output fromthe multiplexer 470 and the output from the third symbol demapper 460, and outputs the determined bits stream.

The MIMO decoder 440 outputs the channel information based upon the channel correlation between antenna pathsas the control signal, thereby being capable of controlling the symbol-demapping operations of the first symbol demapper 450a, the second symbol demapper 450b, and the third symbol demapper 460 and the operations of the data merger 480.

Furthermore, the error correction decoding unit 490 performs error correction decoding on the bit stream outputted from the data merger 480. Accordingly, the error correction decoding unit 490 may adaptively decode data based upon the channel corresponding of the multiple antenna paths by using the MIMO technique. Alternatively, even when the channel correlation is high, the data may be received by using the MIMO technique.

FIG. 5 illustrates an exemplary constellation based upon an antenna path. In this example, the constellationis configured so that the MSB symbol can have a larger symbol interval. In this constellation, ● shows the symbol-mapping of the MSB, and × shows the symbol-mapping of the LSB. Herein, the MSB is symbol-mapped by using the 64QAM method, and the LSB is symbol-mapped by using the QPSK method. Since the symbols marked as × are transmitted and received in a data size of 2bps/Hz, and since the symbols marked as ● are transmitted and received in a data size of 6bps/Hz, the total data size of the transmitted and received data becomes 8bps/Hz.

When such symbol-mapped symbols are respectively transmitted through two antenna paths by using the MIMO technique according to the above-described embodiment of the present invention, and when the channel correlation is low, the MIMO decoder 440 may respectively output the symbols mapped in the same constellation shown in FIG. 5 to the first symbol demapper 450a and the second symbol demapper 450b. More specifically, when the channel correlation between the two antenna paths is low, and when the MIMO decoder 440 performs MIMO decoding, the MIMO decoder 440 may separate the symbols marked as ● from the symbols marked as ×. Accordingly, each of the first symbol demapper 450a and the second symbol demapper 450b may perform symbol-demapping based upon the mapping method of each of the received symbols.

FIG. 6 illustrates an exemplary constellation of received signals, when a channel correlation between each of the antenna paths is high. When the channel correlation is high, the MIMO decoder 440 obtains symbols of a combination signal consisting of a combination of the signals received through respective antenna paths, as shown in FIG. 6. In this case, even if the MIMO decoder 440 performs MIMO decoding, the symbols cannot be separated. However, the symbol of the combination signal consisting of a combination of two-different symbol-mapped signals looks like a 256QAM symbol in a receiver. More specifically, since the third symbol mapper 460 can receive a symbol based upon the 256QAM method, the third symbol mapper 460 may perform symbol-demapping on the symbol by using the 256QAM method. In case the two channels cannot be separated due to a high channel correlation between the antenna paths, symbol-demapping may be performed by using a likelihood ration (LLR) (in this example, the LLR corresponding to 256QAM), which is used in the symbol-demapping method corresponding to the symbol consisting of a combination of signals outputted from each antenna path.In this example, the received data size corresponds to 8bps/Hz, which, in case the channel can be separated, is equivalent to the sum of the data sizes 2bps/Hz and 6bps/Hz being transmitted through each of the antenna paths.

The MIMO decoder 440 may obtain the channel correlation by using the channel status acquired from each of the first demodulator 420a and the second demodulator 420b. The MIMO decoder 440 may then output the channel information based upon the obtained channel correlation as the control information, thereby being capable of controlling the symbol-demapping operations of the first symbol demapper 450a, the second symbol demapper 450b, and the third symbol demapper 460 and the operations of the data merger 480. The data merger 480 uses the control information in order to output bit data as the symbol-demapping result of the signals outputted from each antenna path. Accordingly, even when the signals respective to each antenna path cannot be separated, the hierarchical modulation method may be used to acquired the signal transmitted through each antenna path.

According to this embodiment of the present invention, the data size (bps/Hz) being transmitted to each antenna path may be divided from the MSB to the LSB so as to be separately transmitted, thereby enabling a receiver to receive a signal by adopting the MIMO technique even in a channel environment unsuitable for the MIMO technique. Herein, any modulation method may be used on the data divided from the MSB to the LSB. Furthermore, when channel separation can be performed due to a low channel correlation, since the data of each antenna path may be acquired by each symbol mapper by obtaining the LLR corresponding to a modulation order, the corresponding data is robust against errors. Conversely, when channel separation cannot be performed due to a high channel correlation, the data of each antenna path may be processed as a single combination symbol.

FIG. 7 illustrates a method for transmitting a signal according to an embodiment of the present invention. Error correction encoding is performed on the data that are to be transmitted, and then the error correction encoded data are demultiplexed into data units with respect to the multiple antenna paths from the MSB to the LSB (S110). The demultiplexed data units are symbol-mapped to symbols that are to be transmitted to the respective antenna paths(S120). Herein, the symbol-mapping method may be varied for each of the demultiplexed data sizes. Subsequently, MIMO encoding is performed by using each of the mapped symbols (S130). Thereafter, signal frames are configured by using the MIMO encoded and outputted signals (S140). Then, the signal frames on the antenna paths are modulated and transmitted respectively (S150).

FIG. 8 illustrates a method for receiving a signal according to an embodiment of the present invention. Signals being received through multiple antenna paths are received, synchronization of each received signal is acquired, and then the signals are demodulated (S210).When demodulating the signals of the respective antenna paths, channel information for the respective antenna paths may be obtained. Thereafter, signal frames of the demodulated signals with respect to the respective antenna paths are parsed (S220).

Subsequently, MIMO decoding is performed on the signals of the parsed signal frames with respect to the antenna paths based upon the corresponding channel correlation (S230). The channel correlation may be calculated by using the channel information obtained during the signal demodulation process. Herein, the channel correlation may determine a correlation degree with respect to the channel information obtained from pilot signals included in the signal based upon a predetermined standard.

When the channel correlation is low, based upon the MIMO decoding result, the separated symbols of the signals corresponding to the antenna paths are respectively symbol-demapped, and then the symbol-demapped data are multiplexed, and, when the channel correlation is high, a symbol of a combination signal consisting of a combination of the signals corresponding to each antenna path are symbol-demapped based upon the respective symbol-mapping methods (The symbol-demapped data are outputted according to the channel correlation) (S240). Also, when the channel correlation is low, the symbol-demapping result corresponding to each antenna path corresponds to the data divided from the MSB to the LSB. When the channel correlation is low the multiplexed data are outputted, and when the channel correlation is high the symbol-demapped data are outputted, selectively (S250). Alternatively, the symbol-demapped data are outputted by using both of the multiplexed data and the symbol-demapped data (in symbol-demapper 460) in accordance with the channel correlation.

Finally, error correction decoding is performed on the outputted data (S260).

The data divided from the MSB to the LSB are transmitted in accordance with the MIMO. Thereafter, symbol-mappings corresponding to the respective antenna paths may be performed based upon the channel correlation, or symbol-mapping may be performed on a signal consisting of a combination of the signals corresponding to each antenna path. Accordingly, the receiver can adopt the MIMO technique may be obtained from a channel unsuitable for the MIMO technique. Therefore, signals may still be transmitted and received, even when the channel status cannot be checked due to the absence of an up-link, such as in a broadcasting system, or when the MIMO technique cannot be adopted due to a high channel correlation. Furthermore, by transmitting data divided from the MSB to the LSB using the MIMO technique, signals robust against errors may be transmitted and received.

A plurality of embodiments has been described based upon the best mode for carrying out the present invention.

The present invention may be industrially applied in the fields of broadcasting and telecommunication.

Claims

A method for transmitting a signal, comprising:

performing error correction encoding (S110) on data that are to be transmitted, and demultiplexing the error correction encoded data into data units corresponding to a number of multiple transmission paths, each of the data units being at least one bit divided from a most significant bit (MSB) to a least significant bit (LSB) within the data ;

symbol-mapping (S120) the demultiplexed data units based upon the transmission paths to symbols, respectively

performing (S130) multi-input multi-output (MIMO) encoding on the respective symbol-mapped symbols;

configuring (S140) signal frames that are to be transmitted by using the MIMO-encoded signals, respectively;and

modulating (S150) the signal frames and transmitting the modulated signal frames to the transmission paths, respectively.
The method of claim 1, wherein the symbol-mapping varies depending upon the number of transmission paths.
A method for receiving a signal, the method comprising:

demodulating (S210)signals being received to multiple antennas, respectively ;

parsing (S220) signal frames of the demodulated signals in transmission paths, respectively

performing (S230) MIMO decoding on signals in the signal frames based upon a correlation between channels of the signals being received to the multiple antennas to output MIMO-decoded symbols to multiple paths or a single path in accordance with the correlation ;

symbol-demapping (S240) the MIMO-decoded symbols to symbol-demapped data in accordance with the correlation ,

wherein the MIMO-decoded symbols in the multiple paths are symbol-demapped respectively and the respective symbol-demapped data are multiplexed, or the MIMO-decoded symbols in the single path are symbol-demapped together to symbol-demapped data;

outputting (S250) bit data using at least one of the multiplexed symbol-demapped data and the symbol-demapped data in the single path ; and

error correction decoding (S260)the outputted bit data .
The method of claim 3, wherein the MIMO-decoded symbols in the multiple paths correspond with bit data divided from a most significant bit (MSB) to a least significant bit (LSB), respectively.
The method of claim 3, wherein when the channel correlation is low, the symbol-demapping varies depending upon the number of transmission paths.
An apparatus for transmitting a signal, comprising:

an error correction encoding unit (310) configured to perform error correction encoding on data that are to be transmitted;

a demultiplexer (320) configured to demultiplex the error correction encoded data into data units corresponding to a number of multiple transmission paths, each of the data units being at least one bit divided from a most significant bit (MSB) to a least significant bit (LSB) within the data

a plurality of symbol mappers (330a, 330b) configured to symbol-map the demultiplexed data units based upon the transmission paths to symbols, respectively

a MIMO encoder (340) configured to perform multi-input multi-output (MIMO) encoding on respective symbol-mapped symbols

a plurality of frame forming units (350a, 350b) configured to configure signal frames that are to be transmitted by using MIMO-encoded signals, respectively and

a plurality of modulators (360a, 360b) configured to the signal frames and transmitting the modulated signal frames to the transmission paths, respectively.
The apparatus of claim 6, wherein the plurality of symbol mappers (330a, 330b) is further configured to symbol-map the demultiplexed bits in accordance with different symbol mapping methods.
An apparatus for receiving a signal, comprising:

a plurality of synchronization units (410a, 410b) configured to acquire synchronization of signals being received to multiple antennas, respectively

a plurality of demodulators (420a, 420b) configured to demodulate the signals being received to the multiple antennas, respectively

a plurality of frame parsers (430a, 430b) configured to parse signal frames of the demodulated signals in transmission paths, respectively

a MIMO decoder (440) configured to perform MIMO decoding on signals in the signal frames based upon a correlation between channels of the signals being received to the multiple antennas and output MIMO-decoded symbols to multiple paths or a single path in accordance with the correlation

a plurality of symbol demappers (450a, 450b, 460) configured symbol-demapping the MIMO-decoded symbols to symbol-demapped data in accordance with the correlation,

wherein the MIMO-decoded symbols in the multiple paths are symbol-demapped respectively and the respective symbol-demapped data are multiplexed, or the MIMO-decoded symbols in the single path are symbol-demapped together to symbol-demapped data;

a data merger (480) configured to output bit data using at least one of the multiplexed symbol-demapped data and the symbol-demapped data in the single path; and

an error correction decoding unit (490) configured to error correction decode the outputted bit data.
The apparatus of claim 8, wherein the MIMO-decoded symbols in the multiple paths correspond with bit data divided from a most significant bit (MSB) to a least significant bit (LSB), respectively.
The apparatus of claim 8, wherein the symbol-demapping method varies for each of the plurality of symbol demappers.