摘要:
In a single-carrier frequency division multiple access (SC-FDMA) system that utilizes interleaved FDMA (IFDMA) or localized FDMA (LFDMA), a transmitter generates modulation symbols for different types of data (e.g., traffic data, signaling, and pilot) and performs code division multiplexing (CDM) on at least one data type. For example, the transmitter may apply CDM on signaling and/or pilot sent on frequency subbands and symbol periods that are also used by at least one other transmitter. To apply CDM to a given data type (e.g., signaling), the transmitter performs spreading on the modulation symbols for that data type with an assigned spreading code. CDM may be applied across symbols, samples, samples and symbols, frequency subbands, and so on. The transmitter may perform scrambling after the spreading. The transmitter generates SC-FDMA symbols of the same or different symbol durations for traffic data, signaling, and pilot and transmits the SC-FDMA symbols.
摘要:
Techniques for encoding and decoding data are described. In an aspect, multiple code rates for a forward error correction (FEC) code may be supported, and a suitable code rate may be selected based on packet size. A transmitter may obtain at least one threshold to use for code rate selection, determine a packet size to use for data transmission, and select a code rate from among the multiple code rates based on the packet size and the at least one threshold. In another aspect, multiple FEC codes of different types (e.g., Turbo, LDPC, and convolutional codes) may be supported, and a suitable FEC code may be selected based on packet size. The transmitter may obtain at least one threshold to use for FEC code selection and may select an FEC code from among the multiple FEC codes based on the packet size and the at least one threshold.
摘要:
Techniques for transmitting data in a communication system are described. A packet may be partitioned into multiple subpackets, and each subpacket may be encoded separately. The subpackets may be mapped to resources assigned for transmission of the packet, with at least one subpacket being mapped to a subset of the assigned resources. The assigned resources may include multiple tiles, with each tile corresponding to a block of time frequency resources. The subpackets may be mapped to the tiles such that (i) the subpackets are mapped to equal number of tiles to achieve similar decoding performance, (ii) each subpacket is mapped to at least NMIN tiles, if available, to achieve a certain minimum diversity order for the subpacket, and/or (iii) each subpacket is mapped to a subset of the multiple tiles, if possible, so that the subpacket can be decoded without having to demodulate all of the tiles.
摘要:
A receiver for receiving a pilot generated based on a polyphase sequence having a constant time-domain envelope and a flat frequency spectrum is disclosed. In one design, the receiver includes at least one demodulator and at least one processor. The demodulator(s) receive at least one single-carrier frequency division multiple access (SC-FDMA) symbol transmitted via a communication channel and including pilot symbols generated based on a polyphase sequence. The demodulator(s) remove a cyclic prefix in each SC-FDMA symbol and demodulate the at least one SC-FDMA symbol to obtain received pilot symbols. The processor(s) derive a channel estimate for the communication channel based on the received pilot symbols.
摘要:
Interference management is provided through use of a user-based interference control and/or a network-based interference control. For user-based interference control, the terminals are informed of the inter-sector interference observed by the neighbor sectors and can adjust their transmit powers accordingly so that the inter-sector interference is maintained within acceptable levels. For network-based interference control, each sector is informed of the inter-sector interference observed by the neighbor sectors and regulates data transmissions for its terminals such that the inter-sector interference is maintained within acceptable levels. Each system may utilize only user-based interference control, or only network-based interference control, or both.
摘要:
A transmitter generates a pilot having a constant time-domain envelope and a flat frequency spectrum based on a polyphase sequence. To generate a pilot IFDMA symbol, a first sequence of pilot symbols is formed based on the polyphase sequence and replicated multiple times to obtain a second sequence of pilot symbols. A phase ramp is applied to the second pilot symbol sequence to obtain a third sequence of output symbols. A cyclic prefix is appended to the third sequence of output symbols to obtain an IFDMA symbol, which is transmitted in the time domain via a communication channel. The pilot symbols may be multiplexed with data symbols using TDM and/or CDM. A pilot LFDMA symbol may also be generated with a polyphase sequence and multiplexed using TDM or CDM. A receiver derives a channel estimate based on received pilot symbols and using minimum mean-square error, least-squares, or some other channel estimation technique.
摘要:
Enhanced frequency division multiple access (EFDMA) is a multiplexing scheme that sends modulation symbols in the time domain and achieves a lower PAPR than OFDM. An EFDMA symbol occupies multiple subband groups that are spaced apart in a frequency band, with each subband group containing multiple adjacent subbands. To generate an EFDMA symbol, multiple modulation symbols are mapped onto a first sequence of symbols. A transform (e.g., a DFT) is performed on the first sequence to obtain a second sequence of values. The values in the second sequence corresponding to the subbands used for the EFDMA symbol are retained, and the remaining values are zeroed out to obtain a third sequence of values. An inverse transform (e.g., an IDFT) is performed on the third sequence to obtain a fourth sequence of samples. A phase ramp may be applied on the fourth sequence, and a cyclic prefix is appended to form the EFDMA symbol.
摘要:
A method and apparatus for generating a permutation for reverse link hopping is provided, comprising initializing permutation constants, determining a value for p such that i
摘要:
Techniques for efficiently designing random hopping patterns in a communications system are disclosed. The disclosed embodiments provide for methods and systems for generating random hopping patterns, updating the patterns frequently, generating different patterns for different cells/sectors, and generating patterns of nearby sub-carriers for block hopping.
摘要:
Systems and methodologies are described that facilitate requesting blanking over control resources from one or more interfering eNBs or devices. An eNB, such as a macrocell, femtocell or picocell eNB, can transmit a downlink control blanking message to a UE directing the UE to perform blanking (e.g., for uplink control resources) or request the blanking from the interfering eNBs or devices (e.g., for downlink control resources). The downlink control blanking message can specify the desired control resources and/or information to determine the control resources. Thus, dynamic control blanking is provided such that blanking is requested to mitigate interference over control resources for the small scale eNB. The small scale eNB can subsequently communicate control data to the UE over the control resources; the control data can include a resource blanking message that similarly directs the UE to request blanking of general data resource from the interfering eNBs or devices.