Abstract:
A transmitter, channel coder, and method for coding and transmitting a sequence of symbols in a digital communication system utilizing soft pilot symbols. In one embodiment, the transmitter transmits a set of soft pilot symbols with higher reliability than the remaining symbols in the sequence by modulating the soft pilot symbols with a lower order modulation such as BPSK or QPSK while modulating the remaining symbols with a higher order modulation such as 16QAM or 64QAM. The transmitter shares the modulation type and location (time/frequency/code) of the soft pilot symbols with a receiver. Unlike traditional fixed pilots, the soft pilots still carry some data. Additionally, the soft pilots are particularly helpful in establishing the amplitude reference essential in demodulating the higher order modulation symbols. In another embodiment, soft pilot symbols are inserted by low-level puncturing of channel encoded bits and replacing the punctured bits with known bit patterns.
Abstract:
Improvements in the performance of HARQ operation are achieved by considering two channel coding parameters, the number of filler bits F and the number of dummy bits ND, in the selection of the retransmission settings for HARQ operation. In one exemplary embodiment, an optimal RV setting for the retransmission is selected based on the number of filler bits F and the number of dummy bits ND. In another exemplary embodiment, an address offset to the RV starting point for a selected RV setting is selected based on the number of filler bits F and the number of dummy bits ND.
Abstract:
An error coding circuit comprises a non-systematic convolutional encoder for coding an input bit stream to produce two or more groups of parity bits, an interleaver circuit for interleaving parity bits within each group of parity bits, and a rate-matching circuit for outputting a selected number of the interleaved parity bits ordered by group to obtain a desired code rate.
Abstract:
A quadratic permutation polynomial (QPP) interleaver is described for turbo coding and decoding. The QPP interleaver has the form: (Formula should be inserted here) where the QPP coefficientsf
Abstract:
A block coding method and system for improving the reliability of Channel Quality Indicators (CQI) and antenna weight Indicators (AWI) reporting. A user terminal first generates 8-bit CQI and 2-bit AWI. A codeword generator produces a codeword responsive to these 10 CQI/AWI bits using a codebook or a generator matrix of a (20, 10, 6) code. The (20, 10, 6) code has a minimum Hamming distance of 6. The encoded codeword is transmitted to a receiver for decoding utilizing an identical (20, 10, 6) codebook.
Abstract:
In one aspect, the teachings herein describe an enhanced Reference Signal, RS, that is designed to be available for transmission in any symbol of a subframe. The enhanced RS may be an enhanced Sounding Reference Signal, SRS, or an enhanced DeModulation Reference Signal, DMRS. The enhanced RS provides an advantageous mechanism for channel capture in Listen- Before-Talk, LBT, scenarios, because subsequent to performing a successful Clear Channel Assessment, CCA, a node can begin transmitting the enhanced RS, to thereby capture the channel. The node can then transition into an actual data transmission on the channel according to whatever timing constraints are associated with the data transmission. In at least one embodiment, the enhanced RS is used for capturing an uplink channel on an LTE carrier operated in unlicensed spectrum, as part of a License Assisted Access, LAA, configuration.
Abstract:
A method of operating a wireless communication terminal includes receiving one or more downlink control messages that each contain scheduling information scheduling the wireless termina! to receive a downlink transmission on either a primary carrier or a secondary carrier. The method also includes determining, for each of the downlink control messages, whether that message includes scheduling information for the primary carrier or for a secondary carrier. Additionally, the method includes selecting a format for an uplink control message based on whether any of the downlink control messages includes scheduling information for a secondary carrier, generating an uplink control message based on the selected, format, and transmitting the uplink control message to the base station.
Abstract:
In a communication system using HARQ1 the problem of false ACK detection when no ACK/NACK feedback is transmitted is solved sent by varying the reliability of the scheduling information transmitted to the user terminal on a downlink control channel depending on whether the user terminal is expected to use a first or second uplink channel for sending ACK/NACK feedback. When the user terminal is expected to use the first channel to send ACK/NACK feedback, the base station transmits scheduling information to the user terminal with normal reliability. When the user terminal is expected to send ACK/NACK feedback on the second uplink channel, the base station transmits the signaling information to the user terminal with enhanced reliability. The reliability of the signaling information can be increased, for example, by increasing the transmit power on the downlink control channel, increasing the aggregation level, or a combination thereof.
Abstract:
Control channel information is formulated for transmission in orthogonal frequency division multiplexing (OFDM) systems. In an example embodiment, a method entails formulating control channel information for a transmitting device operating in an OFDM system in which a control channel spans n OFDM symbols, with n being an integer. The method includes acts of allocating, creating, and mapping. Control channel data is allocated to at least one set of resource element groups. At least one order for the set of resource element groups is created in accordance with one or more permutation mechanisms that involve at least one interleaving sequence having a low cross-correlation property. The set of resource element groups is mapped to resource elements of the n OFDM symbols of the control channel responsive to the order that is created using the permutation mechanism(s). The permutation mechanisms may include interleaving sequence(s) and/or cyclic shift(s).
Abstract:
A method and apparatus for providing adaptive cyclic redundancy check (CRC) computation is disclosed. A transport block size is determined. Transport block (TB) CRC bits are computed with a first CRC generator when the TB size is less than or equal to a predetermined threshold. TB CRC bits are computed with a second CRC generator when the transport block size is greater than the predetermined threshold. When the TB is greater than the predetermined threshold, the TB is segmented into code blocks (CBs) and CB CRC bits are computed with the first CRC generator. A method and apparatus for handling adaptively cyclic redundancy check (CRC) encoded transport blocks (TBs) is also disclosed. A TB is received. The TB is CRC checked based on a first CRC generator when the TB size is less than or equal to a predetermined threshold. Code blocks of the TB are CRC checked based on the first CRC generator when the TB size is greater than the predetermined threshold. When the TB size is greater than the predetermined threshold, the code blocks are concatenated, and the TB is CRC checked based on a second CRC generator.