Abstract:
In an advanced adaptive modulation and coding (AMC) scheme, the code rate and the parity-check matrix (PCM) for low-density parity-check (LDPC) codes are adapted according to modulation formats and variable-iteration receivers. The degree distribution for the PCM adaptation is designed by heuristic optimization to minimize the required SNR via an extrinsic information transfer (EXIT) trajectory analysis for finite-iteration decoding. The method uses dynamic window decoding by generating spatially coupled PCM for quasi-cyclic LDPC convolutional coding. The method also provides a way to jointly optimize labeling and decoding complexity for high-order and high-dimensional modulations. The problem to use a large number of different LDPC codes for various modulation formats and variable-iteration decoding is also dealt with by linearly dependent PCM adaptation across iteration count to keep using a common generator matrix. This PCM adaptation can improve a convergence speed of belief propagation decoding and mitigate an error floor issue.
Abstract:
The disclosed embodiments relates to a method performed by an D2D capable UE (800) and also relates to the D2D capable UE (800) for determining link quality of a D2D signal or D2D channel. The method includes receiving (710) a D2D signal or channel transmitted from another D2D capable UE; if detection (720) of the D2D signal or channel is determined to be successful; identifying (730) the identity of the other D2D capable UE; measuring (740) received signal power on resources of the D2D signal or channel; measuring (750) signal strength indicator on resources of the D2D signal or channel or on other resources different from the resources of the D2D signal or channel; and determining (760) link quality based on the measured received signal power and based on the measured signal strength indicator.
Abstract:
The present document relates to optical communication systems. In particular, the present document relates to high efficiency wavelength division multiplexing (WDM) optical communication systems. An optical transmitter (210) adapted to transmit an optical signal on an optical wavelength division multiplexed, referred to as WDM, transmission channel (111) to a corresponding optical receiver (230) is described. The optical transmitter (210) comprises a profiling unit (217) adapted to receive information regarding an equalization filter (270) adapted at the corresponding optical receiver (230), based on a first optical signal received from the optical transmitter (210); a pulse shaping filter unit (212) adapted to filter a sequence of data symbols (211) using a pulse shaping filter, thereby yielding a filtered sequence of data symbols (211); wherein a frequency response (404, 405) of the pulse shaping filter depends on the information regarding the equalization filter (270); and a digital-to-optical converter (214, 215 216) adapted to convert the filtered sequence of data symbols (211) into a second optical signal to be transmitted to the optical receiver (230).
Abstract:
Embodiments of the invention relate to methods and apparatus for link adaptation in a preceded MIMO system. According to one embodiment, there is provided a method for link adaptation in a precoded ΜIΜΟ system. The method comprises: receiving first channel quality information y CQI ; with respect to at least one layer r in a plurality of layers in a link; obtaining a Hybrid Automatic Repeat Request (HARQ) scaling factor μ r that is associated with a HARQ feedback; and interpreting the first channel quality information y CQI into second channel quality information ŷ r based on at least the HARQ scaling factor μ r , , wherein the second channel quality information ŷ r is for adapting the at least one layer r in the plurality of layers. According to another embodiment, there is provided an apparatus for link adaptation in a precoded ΜIΜΟ system.
Abstract:
Methods, systems and devices are provided for receiving, at a receiver device, a data block or file containing a plurality of application symbols, determining the number of application symbols received in the block, generating a metric based on the number of application symbols received in the block, and transmitting the metric to a server. The metric may further be generated based on a number of application symbols that were required to recover the block or file. The server may use the metric received from one or more receiver devices to adjust the transmission settings for additional data transmissions.
Abstract:
User equipment (1100, 1200) supporting multi-carrier operation is adapted to identify whether it is experiencing an excessive interference level on a downlink carrier, which interference may be due to an aggressor carrier. Based on this information, the user equipment deactivates one or more of the downlink carriers so that an adequate downlink quality can be maintained for at least some of the carriers. In an example method, a plurality of activated downlink carriers including at least two non-adjacent downlink carriers in a frequency band are received (1010).The user equipment monitors(1020) quality of at least a subset of the plurality of activated downlink carriers, and determines (1030) that the quality of at least one of the monitored carriers is worse than a predetermined threshold. In response, the user equipment deactivates (1040) one or more of the activated downlink carriers.
Abstract:
The present invention relates to a method in a base station (14, 400) and a base station (14, 400) for predicting a frequency dependent Channel State Information, CSI for scheduling and link adaptation of resource blocks of an operating bandwidth, based on frequency band CSI information related to at least one UE, the method comprising the steps receiving a wideband CSI related to UE (step 302), receiving a UE-selected subband CSI for a bandwidth part (step 302), calculating the difference: the UE-selected subband CSI for the bandwidth part minus a non UE-selected SB CSI the wideband CSI (steps 314, 328, 338), and updating a non UE-selected SB CSI for at least the bandwidth part, based on the calculated difference (steps 318, 332, 342). A faster more reliable prediction method based on UE-selected SB CSI values, is hereby achieved.
Abstract:
L'invention concerne un procédé de pré-égalisation d'un signal de données transmis en duplexage en fréquence (FDD) par une entité communicante d'origine (EC1) comportant des antennes d'origine (A1 1 ,... A1 M 1 ), à destination d'une entité communicante destinataire (EC2) comportant des antennes destinataires (A2 1 ,...A2M 2 ). Le procédé comporte une étape d'émission d'une première séquence pilote par une antenne destinataire (A2 j ); une étape d'estimation par l'entité d'origine d'une première réponse impulsionnelle d'un premier canal de propagation; une étape itérative comportant des sous-étapes d'émission par une antenne d'origine (A1 i ) d'une deuxième séquence pilote modulée par la première réponse impulsionnelle, d'estimation par l'entité destinataire d'une réponse impulsionnelle combinée du premier canal de propagation et d'un deuxième canal de propagation, de retournement temporel de la réponse impulsionnelle combinée, d'émission par l'antenne destinataire d'une troisième séquence pilote modulée par ladite réponse impulsionnelle combinée retournée temporellement, d'estimation d'une réponse impulsionnelle composite des premier et deuxième canaux de propagation, l'étape itérative étant réitérée pour une partie des antennes d'origine et les étapes d'émission d'une première séquence pilote, d'estimation de la première réponse impulsionnelle et étape itérative étant réitérées pour une partie des antennes destinataires; une étape de détermination de coefficients de pré-égalisation du signal de données à partir d'une combinaison d'un ensemble de réponses impulsionnelles composites.