摘要:
A hybrid orthogonal frequency division multiple access (OFDMA) wireless transmit/receive unit (WTRU) and method are disclosed. A WTRU includes a transmitter and a receiver. The receiver processes received data to recover data mapped to the subcarriers using OFDMA. The receiver recovers first input data by separating user data from multi-user spread data and recovers second input data from non-spread data.
摘要:
An orthogonal frequency division multiplexing (OFDM)-code division multiple access (CDMA) system is disclosed. The system includes a transmitter and a receiver. At the transmitter, a spreading and subcarrier mapping unit spreads an input data symbol with a complex quadratic sequence code to generate a plurality of chips and maps each chip to one of a plurality of subcarriers. An inverse discrete Fourier transform is performed on the chips mapped to the subcarriers and a cyclic prefix (CP) is inserted to an OFDM frame. A parallel-to-serial converter converts the time-domain data into a serial data stream for transmission. At the receiver, a serial-to-parallel converter converts received data into multiple received data streams and the CP is removed from the received data. A discrete Fourier transform is performed on the received data streams and equalization is performed. A despreader despreads an output of the equalizer to recover the transmitted data.
摘要:
An orthogonal frequency division multiplexing (OFDM)-code division multiple access (CDMA) system is disclosed. The system includes a transmitter and a receiver. At the transmitter, a spreading and subcarrier mapping unit spreads an input data symbol with a complex quadratic sequence code to generate a plurality of chips and maps each chip to one of a plurality of subcarriers. An inverse discrete Fourier transform is performed on the chips mapped to the subcarriers and a cyclic prefix (CP) is inserted to an OFDM frame. A parallel-to-serial converter converts the time-domain data into a serial data stream for transmission. At the receiver, a serial-to-parallel converter converts received data into multiple received data streams and the CP is removed from the received data. A discrete Fourier transform is performed on the received data streams and equalization is performed. A despreader despreads an output of the equalizer to recover the transmitted data.
摘要:
A hybrid orthogonal frequency division multiple access (OFDMA) system including a transmitter and a receiver is disclosed. The transmitter includes a first spread OFDMA subassembly, a first non-spread OFDMA subassembly and a first common subassembly. The first spread OFDMA subassembly spreads input data and maps the spread data to a first group of subcarriers. The first non-spread OFDMA subassembly maps input data to a second group of subcarriers. The first common subassembly transmits the input data mapped to the first and second group of subcarriers using OFDMA. The receiver includes a second spread OFDMA subassembly, a second non-spread OFDMA subassembly and a second common subassembly. The second common subassembly processes received data to recover data mapped to the subcarriers using OFDMA. The second spread OFDMA subassembly recovers the first input data by separating user data in a code domain and the second non-spread OFDMA subassembly recovers the second input data.
摘要:
A wireless communication method and apparatus for selecting cells in an orthogonal frequency division multiple access (OFDMA) system are disclosed. A wireless transmit/receive unit (WTRU) measures a downlink path loss of a current serving cell and at least one other cell. The WTRU determines whether a path loss difference between the serving cell and the other cell is below a threshold. If the path loss difference is below the threshold, the WTRU measures a channel quality indicator (CQI) for each of the plurality of subcarrier blocks in the downlink of the current serving cell and the other cell, respectively. The WTRU reports the CQIs to a serving Node-B which selects a new cell based on the CQIs. Alternatively, a centralized access gateway (aGW) may select the new serving cell/Node-B, or the cell selection decision made by the serving Node-B may be forwarded to another Node-B via the centralized aGW.
摘要:
A multiple-input multiple-output (MIMO) beamforming-based single carrier frequency division multiple access (SC-FDMA) system is disclosed. At the transmitter, a fast Fourier transform (FFT) is performed on transmission data to generate frequency domain data. The frequency domain transmit data is mapped to assigned subcarriers. An inverse fast Fourier transform (IFFT) is performed on the transmit data mapped to the assigned subcarriers to generate time domain transmit data. The time domain transmit data is transmitted via antennas. At a receiver, an FFT is performed on the received data to generate frequency domain received data. Subcarrier demapping is performed to extract data mapped on the assigned subcarriers. A channel estimator generates a channel matrix which is decomposed into U, D and VH matrices. A channel distortion and interference between transmit and receive antennas are equalized based on the decomposed channel matrices to the extracted frequency domain received data.
摘要:
A method and apparatus for frequency domain joint detection for multicarrier code division multiple access (MC-CDMA) and spread orthogonal frequency division multiple access (OFDMA) systems are disclosed. The apparatus includes a receiver having a frequency domain joint detector, whereby channel distortion and data symbols are jointly equalized and detected by the frequency domain joint detector in a frequency domain. Users of the data symbols may be assigned all or a subset of subcarriers with variable spreading factor codes. Alternatively, the subset of subcarriers may be further divided into multiple partitions and the frequency domain joint detection may be performed on the subcarriers in the partition. The users are assigned a spreading code, which may be a Hadamard code, a spread complex quadratic sequence (SCQS) code or any type of orthogonal spreading code.
摘要:
A method and apparatus for mapping an uplink control channel to a physical channel in a single carrier frequency division multiple access (SC-FDMA) system are disclosed. A wireless transmit/receive unit (WTRU) generates control bits to be carried by a control channel. The WTRU maps the control channel to a plurality of subcarriers among subcarriers in a resource block assigned to the WTRU and to at least one long block (LB) in a sub-frame. The control channel includes a data-non-associated control channel and/or a data-associated control channel. The subcarriers mapped to the data-non-associated control channel may be distributed over all, or a fraction of, at least one resource block. The data-non-associated control channel may be mapped to the subcarriers with one or more subcarriers as a basic unit. The mapped subcarriers may be consecutive in frequency domain. The control bits may be multiplexed with data bits within the LB.
摘要:
A method for transmitting feedback by a user equipment in a wireless communication system includes scheduling a non-contention based uplink channel; and transmitting the feedback on the scheduled uplink channel. The feedback can include a channel quality indicator and an acknowledgement/negative acknowledgement for received downlink data. The feedback can be multiplexed is various ways for efficient transmission.
摘要:
A method and apparatus for sending downlink control information in an orthogonal frequency division multiple access (OFDMA) system are disclosed. A Node-B allocates at least one subcarrier block to each of a plurality of wireless transmit/receive units (WTRUs) for transmission of downlink user data via an OFDMA downlink data channel in accordance with a scheduling mode. The Node-B compiles downlink control information based on the scheduling mode. The Node-B sends the downlink control information to the WTRUs via an OFDMA downlink control channel. The WTRUs receive and process the downlink user data based on the downlink control information.