The Experts below are selected from a list of 5823 Experts worldwide ranked by ideXlab platform

Joan Olmos - One of the best experts on this subject based on the ideXlab platform.

  • on the use of mutual information at bit level for accurate link abstraction in lte with incremental Redundancy h arq
    COST IC1004 Cooperative radio communications for green smart environments: 5th Scientific meeting 24-26 Setembre 2012 Bristol UK, 2012
    Co-Authors: Joan Olmos
    Abstract:

    Link abstraction methods are able to predict the BLER in multicarrier wideband systems using AMC techniques under multipath fading. The basic idea is to map the vector of the subcarrier SNR’s to a single scalar, the Effective SNR (ESNR), which is then used to predict the BLER. This procedure is important during real system operation, since the mobile terminal must report the Channel Quality Indicator (CQI) to the base station, and also for the system level simulators. In order to take into account H-ARQ, it is also interesting to predict the BLER after one or more IR retransmissions have happened. With IR H-ARQ there is an additional complexity, since the BLER performance of a given Redundancy Version (rv) depends on the SNR experienced by the receiver at current rv but also on the SNR of previously received rv's. We propose a novel link abstraction method that can predict the BLER with good accuracy in multipath fading and including the effects of H-ARQ retransmissions. The proposed method is based on estimating the mutual information between the transmitted bits and the received LLRs. We show that, by working at bit level, the effect of unequal error protection in 16 and 64QAM modulations is properly captured without resorting to any set of calibration constants. We also show how to reduce the set of reference BLER curves when working with multiple modulation and code schemes (MCS). Simulation results for LTE downlink with SISO transmission mode are included in the paper.

Lipovac Vlatko - One of the best experts on this subject based on the ideXlab platform.

  • Residual Block Error Rate Prediction for IR HARQ Protocol
    'Mechanical Engineering Faculty in Slavonski Brod', 2020
    Co-Authors: Hamza Mirza, Lipovac Adriana, Lipovac Vlatko
    Abstract:

    This paper provides a simple estimation of the Long Term Evolution (LTE) physical and Medium Access Control (MAC) layer peak transmission performance-the irreducible Block-Error-Rate (BLER) that determines the Hybrid Automatic Repeat Request (HARQ) residual channel available to higher-layer protocols. With this regard, the general pre-HARQ BLER prediction is developed for the Redundancy Version 0 (RV0) codeword transmission, expressed by the Bit-Error-Rate (BER)), considering the cyclic prefix protection against inter-symbol interference sufficient to prevent long error bursts. This implies only sporadic bit error occurrences, exhibiting moderate mutual interdependence that we modelled considering errored bits of each block of data as a sample without replacement and consequently describing it with the hypergeometric distribution instead of the mostly used binomial one. The HARQ BLER estimation model is verified by both problem-dedicated Monte-Carlo simulations and industry-standard LTE software simulation tool, specifically for the LTE FDD downlink channel environment, as the test results exhibit excellent matching with the residual BLER prediction

Hamza Mirza - One of the best experts on this subject based on the ideXlab platform.

  • Residual Block Error Rate Prediction for IR HARQ Protocol
    'Mechanical Engineering Faculty in Slavonski Brod', 2020
    Co-Authors: Hamza Mirza, Lipovac Adriana, Lipovac Vlatko
    Abstract:

    This paper provides a simple estimation of the Long Term Evolution (LTE) physical and Medium Access Control (MAC) layer peak transmission performance-the irreducible Block-Error-Rate (BLER) that determines the Hybrid Automatic Repeat Request (HARQ) residual channel available to higher-layer protocols. With this regard, the general pre-HARQ BLER prediction is developed for the Redundancy Version 0 (RV0) codeword transmission, expressed by the Bit-Error-Rate (BER)), considering the cyclic prefix protection against inter-symbol interference sufficient to prevent long error bursts. This implies only sporadic bit error occurrences, exhibiting moderate mutual interdependence that we modelled considering errored bits of each block of data as a sample without replacement and consequently describing it with the hypergeometric distribution instead of the mostly used binomial one. The HARQ BLER estimation model is verified by both problem-dedicated Monte-Carlo simulations and industry-standard LTE software simulation tool, specifically for the LTE FDD downlink channel environment, as the test results exhibit excellent matching with the residual BLER prediction

Lipovac Adriana - One of the best experts on this subject based on the ideXlab platform.

  • Residual Block Error Rate Prediction for IR HARQ Protocol
    'Mechanical Engineering Faculty in Slavonski Brod', 2020
    Co-Authors: Hamza Mirza, Lipovac Adriana, Lipovac Vlatko
    Abstract:

    This paper provides a simple estimation of the Long Term Evolution (LTE) physical and Medium Access Control (MAC) layer peak transmission performance-the irreducible Block-Error-Rate (BLER) that determines the Hybrid Automatic Repeat Request (HARQ) residual channel available to higher-layer protocols. With this regard, the general pre-HARQ BLER prediction is developed for the Redundancy Version 0 (RV0) codeword transmission, expressed by the Bit-Error-Rate (BER)), considering the cyclic prefix protection against inter-symbol interference sufficient to prevent long error bursts. This implies only sporadic bit error occurrences, exhibiting moderate mutual interdependence that we modelled considering errored bits of each block of data as a sample without replacement and consequently describing it with the hypergeometric distribution instead of the mostly used binomial one. The HARQ BLER estimation model is verified by both problem-dedicated Monte-Carlo simulations and industry-standard LTE software simulation tool, specifically for the LTE FDD downlink channel environment, as the test results exhibit excellent matching with the residual BLER prediction

Farooq Khan - One of the best experts on this subject based on the ideXlab platform.

  • method and apparatus of improved circular buffer rate matching for turbo coded mimo ofdm wireless systems
    2008
    Co-Authors: Jiannan Tsai, Zhouyue Pi, Farooq Khan
    Abstract:

    Methods and apparatus for determining the starting points of Redundancy Version transmissions in a circular rate matching operation. At least one block of information bits to be transmitted are encoded to generate a plurality of coded bits, which are then segmented into a plurality of sub-blocks of coded bits. Each of the sub-blocks of coded bits is interleaved by using a certain interleaver. The interleaved coded bits of the plurality of sub-blocks are collected and filled into a circular buffer having a plurality of Redundancy Versions in the circular buffer, with each Redundancy Version corresponding to a starting bit index in the circular buffer. For each transmission, a subset of bits are selected from the circular buffer by selecting a Redundancy Version from among the plurality of Redundancy Version. The selected subset of bits are modulated by using a certain modulation scheme, and are transmitted via at least one antenna. The Redundancy Versions of the circular being determined such that in at least one pair of Redundancy Versions, the number of bits between the starting point of a first Redundancy Version and the starting point of a second Redundancy Version is not divisible by at least one modulation order.