Abstract: Systems and methods for providing relay in communications systems are disclosed. The relay may receive signals from user equipments (UEs) transmitting coded signals. The relay may receive turbo coded signals from the UEs. The relay station may encode a network channel for transmission to the base station using a recursive systematic convolutional (“RSC”) code. The use of RSC for the network code enables the base station to form as well a distributed turbo code as one can with the UE coded signals. In this manner the base station may recover the signal estimates for the UE signals with lower error probability when estimates at the relay station include errors due to imperfect reception. The use of the relay station and the RSC network code enables the base station to receive UE signals with lower error probability even when the transmission path from the UE is imperfect.

Abstract: A multicarrier data transmission scheme is provided. According to the provided scheme, a radio transmitter encodes data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit. The data bits are preferably encoded with an irregular low-density parity check (LDPC) code. The encoded data bits are then mapped to symbols. The symbols are allocated to subcarriers of a multicarrier radio signal on the basis of channel state information obtained from the radio receiver and the degree used with respect to each symbol. On the basis of the channel state information, a number of subcarriers are truncated due to high attenuation, and the number of subcarriers to be truncated relative to the total number of subcarriers is substantially fixed. The available transmit power to the non-truncated subcarriers. The multicarrier signal comprising symbols on the non-truncated subcarriers is then transmitted to the radio receiver.

Abstract: A QRD-M decomposition includes a first and a sequential second stage, at least. In the first stage, M branches are selected from among more than M branches entering the first stage as survive branches from which multiple decompositions are calculated. In the second stage, more than M branches are selected from among those branches entering the second stage as survive branches from which multiple decompositions are calculated. The symbol of the received signal is decided from a branch that is a survive branch of both the first and second stages. The second stage may be within a window that may include additional stages at which the pruning decision down to M survive branches is delayed. One or more windows may be used in a single QRD-M decomposition. In an embodiment, all branches entering the second stage are survive branches. It is shown that the marginal increased computational load increases accuracy.

Abstract: Systems and methods for providing relay in communications systems are disclosed. The relay may receive signals from user equipments (UEs) transmitting coded signals. The relay may receive turbo coded signals from the UEs. The relay station may encode a network channel for transmission to the base station using a recursive systematic convolutional (“RSC”) code. The use of RSC for the network code enables the base station to form as well a distributed turbo code as one can with the UE coded signals. In this manner the base station may recover the signal estimates for the UE signals with lower error probability when estimates at the relay station include errors due to imperfect reception. The use of the relay station and the RSC network code enables the base station to receive UE signals with lower error probability even when the transmission path from the UE is imperfect.

Abstract: In a multiple-input multiple output (MIMO) system, high-rate data transmission is achieved by dividing the original data stream into several parallel data substreams, each of which is transmitted from a corresponding transmit antenna (spatial multiplexing) and received by multiple receive antennas. The number of spatial streams depends on the number of antennas. In a receiver, a search-tree based QR Decomposition-M (QRD-M) algorithm is used. According to the invention, multiple spatial signal streams received from a MIMO channel are pre-ordered based on modulation alphabets of said received spatial signal streams prior to performing a QRD-M detection.

Abstract: A QRD-M decomposition includes a first and a sequential second stage, at least. In the first stage, M branches are selected from among more than M branches entering the first stage as survive branches from which multiple decompositions are calculated. In the second stage, more than M branches are selected from among those branches entering the second stage as survive branches from which multiple decompositions are calculated. The symbol of the received signal is decided from a branch that is a survive branch of both the first and second stages. The second stage may be within a window that may include additional stages at which the pruning decision down to M survive branches is delayed. One or more windows may be used in a single QRD-M decomposition. In an embodiment, all branches entering the second stage are survive branches. It is shown that the marginal increased computational load increases accuracy.

Abstract: A method for providing a plurality of user equipment with a pilot sequence, the plurality of user equipment being allocated a bandwidth, the method including scattering the pilot sequence over the bandwidth orthogonally in the frequency domain among the plurality of user equipment.

Abstract: An approach is provided for subblock-wise frequency domain equalization, wherein a data block of a received signal is segmented into at least two subblocks at a receiving end of a transmission channel. The subblocks are then equalized separately in the frequency domain, and equalized subblocks are combined to obtain an equalized signal. Thereby, Doppler induced interference can be suppressed to achieve enhanced robustness to high Doppler and compensate performance degradation due to rapidly varying channels.

Abstract: The present invention discloses a method for pilot channel tracking based on multipath channel barycenter tracking loop, comprises steps of evaluating multipath fading channel parameters, calculating the barycenter of a multipath energy window, and loop filtering and adjusting the phase of spread spectrum sequence codes. The method of the invention does not need to individually track each delay path, thereby improving the tracking performance and timing recovery stability of a spread spectrum receiver. Only a multipath channel evaluator and a multipath energy window barycenter calculating means are used to track PN signals from a plurality of signal sources, thereby reducing hardware. Thus, a novelty coherent spread spectrum receiver can be constituted by cooperating with other parts.

Abstract: A method for transmitting information in a communication system from a first station to a second station. The method includes modulating a first part of the information according to a first modulation scheme to provide a first modulated data block; modulating a second part of the information according to a second different modulation scheme to provide a second modulated data block; appending the first modulated data block to the second modulated data block to form a composite data block; and transmitting the data block.

Abstract: A method of transmitting data in a communications system comprising a first station and a second station. The method for transmitting data in a communications system comprises encoding data; allocating the encoded data to different quality channels based on how data is encoded; and transmitting the encoded data on the allocated channels from the first station to the second station.

Abstract: This invention relates to a method, device, computer program and computer program product for determining a mapping for a sequence of information-carrying values, including determining K representations of a sequence of information-carrying values in K successive stages, respectively, wherein in a first stage, a first representation of said K representations is determined to be equal to said sequence of information-carrying values, wherein in subsequent stages, each representation is determined by performing a mapping operation on the representation determined in the preceding stage, and wherein said mapping operation is the same for each stage; calculating, in each stage, a parameter from a transformation of the representation determined in said stage; and determining for which stage of said K stages an extreme value of said parameter is calculated.

Abstract: The present invention discloses an apparatus for initial synchronization and cell search in a CDMA system based on multipath energy window. The apparatus perform initial synchronization and adjacent cell search by using multipath energy window based on the processing method of multipath energy window. The apparatus can be implemented based on a parallel correlator bank. This invention also provides the application of the apparatus to a coherent spreading receiver.

Abstract: The Spread Spectrum integration coherent receiver of the invention employs a time division multiplexing correlator bank and thus obtained coherent channel evaluator as a core. The receiver can execute initial PN synchronization, RAKE diversity coherent combination, AFC and adjacent cell search and combination receipt, and soft handoff. Further, “part capture in parallel based on slide energy window” and “tracking loop based on energy window barycenter” are introduced into the receiver of the invention, thereby simplifying the structure of the RAKE receiver. The receiver is capable of overcoming multipath fading, ensuring the RAKE receipt performance.

Abstract: A multicarrier data transmission scheme is provided. According to the provided scheme, a radio transmitter encodes data bits with different degrees, the degree of an encoded data bit being defined by the number of parity check equations protecting the data bit. The data bits are preferably encoded with an irregular low-density parity check (LDPC) code. The encoded data bits are then mapped to symbols. The symbols are allocated to subcarriers of a multicarrier radio signal on the basis of channel state information obtained from the radio receiver and the degree used with respect to each symbol. On the basis of the channel state information, a number of subcarriers are truncated due to high attenuation, and the number of subcarriers to be truncated relative to the total number of subcarriers is substantially fixed. The available transmit power to the non-truncated subcarriers. The multicarrier signal comprising symbols on the non-truncated subcarriers is then transmitted to the radio receiver.

Abstract: An automatic frequency correction (AFC) apparatus used for CDMA multipath fading channels comprises a frequency-offset evaluator, an automatic frequency correction loop filter and a carrier frequency adjuster. The present invention provides a “multipath energy window” designing method for the non-determinacy of multipath signals in mobile communication environment. Frequency-offset information can be extracted from the multipath energy window by a simple calculation and evaluated by a maximal SNR weight process. This invention also provides a step-variable accumulation adjusting method and greatly improves the response speed of the AFC apparatus as compared with a conventional loop filter, whereby supplies better AFC required for CDMA mobile terminals.

Abstract: A system and method for a transceiver structure, where Different Known Guard Intervals (DKGI) are appended to multiple, consecutive data blocks and are then used in combination with Channel State Information (CSI) to restore cyclic convolution in the time domain. Once restored, the CSI and cyclic convolution are transformed into the frequency domain by FFT processing to facilitate equalization of the channel through Frequency Domain Equalization (FDE). Through performance of time domain channel estimation, there is no need for pilot signals and related overhead, thus channel capacity is enhanced.

Abstract: The present invention discloses a method for pilot channel tracking based on multipath channel barycenter tracking loop, comprises steps of evaluating multipath fading channel parameters, calculating the barycenter of a multipath energy window, and loop filtering and adjusting the phase of spread spectrum sequence codes. The method of the invention does not need to individually track each delay path, thereby improving the tracking performance and timing recovery stability of a spread spectrum receiver. Only a multipath channel evaluator and a multipath energy window barycenter calculating means are used to track PN signals from a plurality of signal sources, thereby reducing hardware. Thus, a novelty coherent spread spectrum receiver can be constituted by cooperating with other parts.

Abstract: The Spread Spectrum integration coherent receiver of the invention employs a time division multiplexing correlator bank and thus obtained coherent channel evaluator as a core. The receiver can execute initial PN synchronization, RAKE diversity coherent combination, AFC and adjacent cell search and combination receipt, and soft handoff. Further, “part capture in parallel based on slide energy window” and “tracking loop based on energy window barycenter” are introduced into the receiver of the invention, thereby simplifying the structure of the RAKE receiver. The receiver is capable of overcoming multipath fading, ensuring the RAKE receipt performance.

Abstract: The present invention discloses an apparatus for initial synchronization and cell search in a CDMA system based on multipath energy window. The apparatus perform initial synchronization and adjacent cell search by using multipath energy window based on the processing method of multipath energy window. The apparatus can be implemented based on a parallel correlator bank. This invention also provides the application of the apparatus to a coherent spreading receiver.