User signal transmitting and receiving method, apparatus and system in OFDMA system

A user signal receiving method in an Orthogonal Frequency-Division Multiple Access (OFDMA) system, wherein the OFDMA system comprises multiple terminals and multiple Base Transceiver Stations (BTSs), a user communicates with the BTSs via the terminals, and in an OFDMA access manner, a radio resource is divided into multiple two-dimensional time-frequency grids, and wherein all the two-dimensional time-frequency grids of each timeslot are divided into multiple sub-channels, in which each sub-channel comprises Nf sub-carriers overlapping in time, where Nf≧4, and in the Nf sub-carriers comprised in each sub-channel, a maximum value of a frequency interval between adjacent sub-carriers is three times or more than three times of a minimum value of the frequency interval between the adjacent sub-carriers;

• and,
• when any one of the terminals and BTSs acts as a receiver used for receiving a user message of the user, the method comprises:
• performing, in turn, Fast Fourier Transform and inverse mapping on a time-domain signal of the user to obtain a modulating signal of the user, wherein the inverse mapping is based on a two-dimensional time-frequency grid set allocated by a network side to the user, where the two-dimensional time-frequency grid set is a union set of one or more sub-channels, in which a quantity of the one or more sub-channels is determined by a size of the user message, and a time-frequency position of the sub-channel is selected according to a predetermined rule;
• learning a spatial and time-frequency characteristic of an interference from one or more null signals respectively in one or more two-dimensional time-frequency grids comprised in each sub-channel using the modulating signal of the user, and performing interference suppression using the spatial and time-frequency characteristic of the interference obtained from the learning, wherein the one or more null signals are inserted into the one or more two-dimensional time-frequency grids comprised in each sub-channel by a transmitter of the user message in generating a frequency-domain signal;
• and,
• demodulating the modulating signal of the user with the interference suppression being performed to obtain the user message of the user.

A user signal transmitting apparatus in an Orthogonal Frequency-Division Multiple Access (OFDMA) system, wherein in an OFDMA access manner, a radio resource is divided into multiple two-dimensional time-frequency grids, and wherein all the two-dimensional time-frequency grids of each timeslot are divided into multiple sub-channels, in which each sub-channel comprises Nf sub-carriers overlapping in time, where Nf≧4, and in the Nf sub-carriers comprised in each sub-channel, a maximum value of a frequency interval between adjacent sub-carriers is three times or more than three times of a minimum value of the frequency interval between the adjacent sub-carriers;

• and,
• the apparatus comprises:
• a message modulating unit, adapted to generate a modulating signal of a user based on a user message to be sent from the user;
• a modulating signal mapping unit, adapted to map the modulating signal of the user from the message modulating unit to a two-dimensional time-frequency grid set allocated by a network side to the user, to generate a frequency-domain signal of the user, wherein the two-dimensional time-frequency grid set is a union set of one or more sub-channels, in which a quantity of the one or more sub-channels is determined by a size of the user message, and a time-frequency position of the sub-channel is selected according to a predetermined rule;
• and
• an Inverse Fast Fourier Transform (IFFT) transmitting unit, adapted to perform Inverse Fast Fourier Transform on the frequency-domain signal of the user from the modulating signal mapping unit to generate a time-domain signal of the user, and to transmit the time-domain signal.

A user signal receiving apparatus in an Orthogonal Frequency-Division Multiple Access (OFDMA) system, wherein in an OFDMA access manner, a radio resource is divided into multiple two-dimensional time-frequency grids, and wherein all the two-dimensional time-frequency grids of each timeslot are divided into multiple sub-channels, in which each sub-channel comprises Nf sub-carriers overlapping in time, where Nf≧4, and in the Nf sub-carriers comprised in each sub-channel, a maximum value of a frequency interval between adjacent sub-carriers is three times or more than three times of a minimum value of the frequency interval between the adjacent sub-carriers;

• and,
• the apparatus is adapted to receive a user message from a user, and comprises:
• a Fast Fourier Transform FFT receiving unit, adapted to receive a time-domain signal of the user, and to perform Fast Fourier Transform on the time-domain signal of the user;
• an inverse mapping unit, adapted to perform inverse mapping on the time-domain signal from the FFT receiving unit based on a two-dimensional time-frequency grid set allocated by a network side to the user to obtain a modulating signal, wherein the two-dimensional time-frequency grid set is a union set of one or more sub-channels, in which a quantity of the one or more sub-channels is determined by a size of the user message, and a time-frequency position of the sub-channel is selected according to a predetermined rule;
• an interference suppressing unit, adapted to learn a spatial and time-frequency characteristic of an interference from one or more null signals in each sub-channel therein using the modulating signal from the inverse mapping unit, and to perform interference suppression on the modulating signal using the spatial and time-frequency characteristic of the interference obtained from learning;
• and,
• a demodulating unit, adapted to demodulate the modulating signal with the interference suppression being performed from the interference suppressing unit to obtain the user message.

A user signal transmitting system of Orthogonal Frequency-Division Multiple Access (OFDMA), comprising:

• at least one Base Transceiver Station (BTS) and at least one terminal, wherein a user communicates with the BTS via the terminal, and in an OFDMA access manner, a radio resource is divided into multiple two-dimensional time-frequency grids, and wherein:
• the terminal is adapted to generate, when transmitting a user message of the user to the BTS, a modulating signal of the user based on the user message to be sent;
• to map the modulating signal of the user to a two-dimensional time-frequency grid set allocated by the BTS to itself, and to insert one or more null signals respectively into one or more two-dimensional time-frequency grids comprised in each sub-channel to generate a frequency-domain signal of the user;
• and to perform Inverse Fast Fourier Transform on the frequency-domain signal of the user to generate a time-domain signal of the user, and to transmit the time-domain signal;
• and,
• the BTS is adapted to allocate sub-channels, wherein all the two-dimensional time-frequency grids of each timeslot are divided into multiple sub-channels, in which each sub-channel comprises Nf sub-carriers overlapping in time, where Nf≧4, and in the Nf sub-carriers comprised in each sub-channel, a maximum value of a frequency interval between adjacent sub-carriers is three times or more than three times of a minimum value of the frequency interval between the adjacent sub-carriers;
• to allocate a two-dimensional time-frequency grid set to the user when receiving the user message from the terminal, wherein the two-dimensional time-frequency grid set is a union set of one or more sub-channels, in which a quantity of the one or more sub-channels is determined by a size of the user message, and a time-frequency position of the sub-channel is selected according to a predetermined rule;
• to perform, in turn, Fast Fourier Transform and inverse mapping on the time-domain signal of the user from the terminal to obtain the modulating signal of the user;
• to learn a spatial and time-frequency characteristic of an interference from one or more null signals respectively in one or more two-dimensional time-frequency grids comprised in each sub-channel using the modulating signal of the user, and to perform interference suppression on the modulating signal of the user using the spatial and time-frequency characteristic of the interference obtained from the learning, and to demodulate the modulating signal of the user with the interference suppression being performed to obtain the user message of the user.

A user signal transmitting system of Orthogonal Frequency-Division Multiple Access (OFDMA), comprising:

• at least one Base Transceiver Station (BTS) and at least one terminal, wherein a user communicates with the BTS via the terminal, and in an OFDMA access manner, a radio resource is divided into multiple two-dimensional time-frequency grids, and wherein:
• the BTS is adapted to allocate sub-channels, wherein all the two-dimensional time-frequency grids of each timeslot are divided into multiple sub-channels, in which each sub-channel comprises Nf sub-carriers overlapping in time, where Nf≧4, and in the Nf sub-carriers comprised in each sub-channel, a maximum value of a frequency interval between adjacent sub-carriers is three times or more than three times of a minimum value of the frequency interval between the adjacent sub-carriers;
• to generate, when transmitting a user message of the user to the terminal, a modulating signal of the user based on the user message to be sent;
• to map the modulating signal of the user to a two-dimensional time-frequency grid set allocated by itself to the user, and to insert one or more null signals respectively into one or more two-dimensional time-frequency grids comprised in each sub-channel to generate a frequency-domain signal of the user;
• and to perform Inverse Fast Fourier Transform on the frequency-domain signal of the user to generate a time-domain signal of the user, and to transmit the time-domain signal, wherein the two-dimensional time-frequency grid set is a union set of one or more sub-channels, in which a quantity of the one or more sub-channels is determined by a size of the user message, and a time-frequency position of the sub-channel is selected according to a predetermined rule;
• and,
• the terminal is adapted to perform, in turn, Fast Fourier Transform and inverse mapping on the time-domain signal of the user from the BTS, to obtain the modulating signal of the user, to learn a spatial and time-frequency characteristic of an interference from the one or more null signals in the one or more two-dimensional time-frequency grids comprised in each sub-channel using the modulating signal of the user;
• and to perform interference suppression on the modulating signal of the user using the spatial and time-frequency characteristic of the interference obtained from learning, and to demodulate the modulating signal of the user with the interference suppression being performed to obtain the user message of the user.