The Experts below are selected from a list of 34767 Experts worldwide ranked by ideXlab platform
Lorant Farkas - One of the best experts on this subject based on the ideXlab platform.
-
ISIT - Universal random access error exponents for Codebooks with different word-lengths
2017 IEEE International Symposium on Information Theory (ISIT), 2017Co-Authors: Lorant FarkasAbstract:Csiszar's channel coding theorem for multiple code-books is generalized allowing the codeword lengths differ across Codebooks. Also in this case, for each codebook an error exponent can be achieved that equals the random coding exponent for this codebook alone, in addition, the overload detection failure probability tends to 0. This is proved even for sender and receiver not knowing the channel. As a corollary, a substantial improvement is obtained when the sender knows the channel.
-
Universal Random Access Error Exponents for Codebooks of Different Word-Lengths
arXiv: Information Theory, 2016Co-Authors: Lorant FarkasAbstract:Csisz\'ar's channel coding theorem for multiple Codebooks is generalized allowing the codeword lenghts differ across Codebooks. Also in this case, for each codebook an error exponent can be achieved that equals the random coding exponent for this codebook alone, in addition, erasure detection failure probability tends to 0. This is proved even for sender and receiver not knowing the channel. As a corollary, a substantial improvement is obtained when the sender knows the channel.
Amine Maaref - One of the best experts on this subject based on the ideXlab platform.
-
Unequal Error Protection SCMA Codebooks
IEEE Transactions on Vehicular Technology, 2019Co-Authors: Zeina Mheich, Lei Wen, Pei Xiao, Amine MaarefAbstract:This paper investigates the design of unequal error protection (UEP) Codebooks for sparse code multiple access (SCMA) systems. We propose a joint low-density parity check (LDPC) code and SCMA codebook design approach by incorporating cloud partitioning of codewords in the design of SCMA Codebooks with different protection levels. The protection levels of the SCMA Codebooks could be optimized based on the existing error correction code. Simulation results show that significant gains could be obtained using code-aware UEP SCMA Codebooks, compared to Codebooks designed independently of the channel code.
-
Design of SCMA Codebooks Based on Golden Angle Modulation
IEEE Transactions on Vehicular Technology, 2019Co-Authors: Zeina Mheich, Lei Wen, Pei Xiao, Amine MaarefAbstract:In this paper, we propose to use golden angle modulation (GAM) points to construct Codebooks for uplink and downlink sparse code multiple access (SCMA) systems. We provide two categories of Codebooks with one and two optimization parameters, respectively. The advantages of the proposed design method are twofold: $1)$ the number of optimization variables is independent of codebook and system parameters; and $2)$ it is simple to implement. In the downlink, we use GAM points to build a multidimensional mother constellation for SCMA Codebooks, while in the uplink GAM points are directly mapped to user Codebooks. The proposed Codebooks exhibit good performance with low peak to average power ratio compared to the Codebooks proposed in the literature based on constellation rotation and interleaving.
Robert W. Heath - One of the best experts on this subject based on the ideXlab platform.
-
Limited feedback with joint CSI quantization for multicell cooperative generalized eigenvector beamforming
2010 IEEE International Conference on Acoustics Speech and Signal Processing, 2010Co-Authors: Ramya Bhagavatula, Robert W. HeathAbstract:Existing work on limited feedback for cooperative multicell beamforming quantizes the desired and interfering channel state information (CSI) using separate Codebooks. In this paper, it is shown that comparatively higher sum-rates can be obtained by jointly quantizing the desired and interfering CSI using a single codebook. A selection criterion is developed for random vector quantization (RVQ) to show that joint quantization with RVQ yields higher sum-rates than those obtained using separate Codebooks. The generalized Lloyd algorithm is then used to generate Codebooks using the codeword design strategy proposed in this paper. Simulations are used to show that the proposed joint quantization approaches perform almost as well as the full CSI case.
-
kerdock codes for limited feedback precoded mimo systems
IEEE Transactions on Signal Processing, 2009Co-Authors: Takao Inoue, Robert W. HeathAbstract:Codebook based limited feedback is a practical way to obtain partial channel state information at the transmitter in a precoded multiple-input multiple-output wireless system. In this correspondence, we propose a systematic codebook design. The proposed Kerdock codebook consists of multiple mutually unbiased unitary basis matrices with quaternary alphabet and the identity matrix. We propose to derive the beamforming and precoding Codebooks from this base codebook, eliminating the requirement to store multiple Codebooks. Furthermore, we show that quaternary alphabet facilitates efficient codebook storage and codeword search. We derive the chordal distance for two and four antenna Codebooks, showing that the proposed Codebooks compare favorably with prior designs. Monte Carlo simulations compare achievable rates and error rates for different Codebooks sizes.
-
Progressive refinement for high resolution limited feedback multiuser MIMO beamforming
2008 42nd Asilomar Conference on Signals Systems and Computers, 2008Co-Authors: Robert W. Heath, Tao Wu, A.c.k. Anthony C K SoongAbstract:Limited feedback enables the practical use of channel state information in single user and multiple user MIMO (multiple input multiple output) wireless communication systems. Using the limited feedback concept, channel state information at the receiver is quantized by choosing a representative element from a codebook known to both the receiver and transmitter. Unfortunately, achieving the high resolution required by multiuser MIMO communication is challenging due to the large size Codebooks required. This paper proposes a progressive refinement concept that uses a base codebook quantization followed by a progressively scaled local codebook to enable high resolution quantization and reconstruction.
-
kerdock codes for limited feedback mimo systems
International Conference on Acoustics Speech and Signal Processing, 2008Co-Authors: Takao Inoue, Robert W. HeathAbstract:A codebook based limited feedback strategy is a practical way to obtain partial channel state information at the transmitter in precoded multiple-input multiple-output (MIMO) wireless systems. Construction of conventional Codebooks, such as Grassmannian and Fourier Codebooks, relies on nonlinear search and iterative algorithms which often does not exhibit structure to ease storage or online search computation. Furthermore, multiple Codebooks are needed to support beamforming and spatial multiplexing. In this paper, we propose a new codebook design based on Kerdock codes and mutually unbiased bases which enjoys performance similar to previously known Codebooks. The proposed Kerdock codebook with quaternary alphabet has systematic construction, reduced storage, and reduced online search computation. Special structure in the codebook is used to derive a spatial multiplexing codebook from multiple columns of the beamforming codebook resulting in further storage reduction.
-
ICASSP - Kerdock codes for limited feedback MIMO systems
2008 IEEE International Conference on Acoustics Speech and Signal Processing, 2008Co-Authors: Takao Inoue, Robert W. HeathAbstract:A codebook based limited feedback strategy is a practical way to obtain partial channel state information at the transmitter in precoded multiple-input multiple-output (MIMO) wireless systems. Construction of conventional Codebooks, such as Grassmannian and Fourier Codebooks, relies on nonlinear search and iterative algorithms which often does not exhibit structure to ease storage or online search computation. Furthermore, multiple Codebooks are needed to support beamforming and spatial multiplexing. In this paper, we propose a new codebook design based on Kerdock codes and mutually unbiased bases which enjoys performance similar to previously known Codebooks. The proposed Kerdock codebook with quaternary alphabet has systematic construction, reduced storage, and reduced online search computation. Special structure in the codebook is used to derive a spatial multiplexing codebook from multiple columns of the beamforming codebook resulting in further storage reduction.
Zeina Mheich - One of the best experts on this subject based on the ideXlab platform.
-
Unequal Error Protection SCMA Codebooks
IEEE Transactions on Vehicular Technology, 2019Co-Authors: Zeina Mheich, Lei Wen, Pei Xiao, Amine MaarefAbstract:This paper investigates the design of unequal error protection (UEP) Codebooks for sparse code multiple access (SCMA) systems. We propose a joint low-density parity check (LDPC) code and SCMA codebook design approach by incorporating cloud partitioning of codewords in the design of SCMA Codebooks with different protection levels. The protection levels of the SCMA Codebooks could be optimized based on the existing error correction code. Simulation results show that significant gains could be obtained using code-aware UEP SCMA Codebooks, compared to Codebooks designed independently of the channel code.
-
Design of SCMA Codebooks Based on Golden Angle Modulation
IEEE Transactions on Vehicular Technology, 2019Co-Authors: Zeina Mheich, Lei Wen, Pei Xiao, Amine MaarefAbstract:In this paper, we propose to use golden angle modulation (GAM) points to construct Codebooks for uplink and downlink sparse code multiple access (SCMA) systems. We provide two categories of Codebooks with one and two optimization parameters, respectively. The advantages of the proposed design method are twofold: $1)$ the number of optimization variables is independent of codebook and system parameters; and $2)$ it is simple to implement. In the downlink, we use GAM points to build a multidimensional mother constellation for SCMA Codebooks, while in the uplink GAM points are directly mapped to user Codebooks. The proposed Codebooks exhibit good performance with low peak to average power ratio compared to the Codebooks proposed in the literature based on constellation rotation and interleaving.
Essam Sourour - One of the best experts on this subject based on the ideXlab platform.
-
Codebook-based precoding for generalized spatial modulation with diversity
EURASIP Journal on Wireless Communications and Networking, 2019Co-Authors: Essam SourourAbstract:This paper investigates codebook-based precoding for spatial modulation (SM) and generalized spatial modulation (GSM) systems. Codebook-based precoding allows the system to dispense with full channel state information at the transmitter (CSIT). This considerably reduces the feedback overhead. Phase-only Codebooks with systematic structure are investigated since they avoid increasing the peak to average power ratio of the transmitted signal. It is shown that the proposed phase-only Codebooks yield equivalent performance to published Codebooks that involve gain and phase. In addition, a gain-only codebook is designed to supplement the phase-only codebook and reduce the bit error rate (BER) further. We also compare the performance with the Grassmannian Codebooks which are proposed for other multiple-in-multiple-out (MIMO) systems. In GSM systems, several antennas are simultaneously active as a transmit antenna combination (TAC). The BER performance of unprecoded GSM systems is typically inferior to SM systems due to correlation among TACs. However, with codebook precoding, this effect is mitigated, and the performance of the GSM system becomes superior to the SM system. We investigate codebook precoding for GSM systems where precoding is performed per-TAC or per-antenna. Moreover, we investigate the GSM system where the TACs are selected adaptively based on the achievable benefit from codebook precoding. Using computer simulation, it is shown that the performance of the proposed Codebooks is very promising in both SM and GSM systems. Per-antenna precoding is superior to per-TAC precoding. Adaptive TACs selection further improves performance.
-
Transmit Precoding Based Low Complexity Codebooks and Finite Feedback Rate for Space Shift Keying MIMO Systems
Wireless Personal Communications, 2018Co-Authors: Mohammed Al-ansi, Essam SourourAbstract:Transmit Precoding (TPC) considerably improves the performance of Space Shift Keying (SSK) systems. Codebook-based TPC is able to tackle several difficulties encountered by non-codebook TPC techniques. Channel State Information (CSI) is required at the receiver only, and the index of the best codeword is easily identified and fed-back from receiver to transmitter with low rate message. Motivated by these advantages, this paper contributes to the codebook-based TPC in the following aspects. First, the paper presents a Factorized form of the Full-Combination (FC) codebook with phase rotation only, and shows that only four phases are needed, which significantly simplifies practical implementation. As a second contribution, the paper introduces two statistically filtered Codebooks: Index-Filtration FC and Average-Filtration FC. These Codebooks considerably reduce system complexity due to their small codebook size, while maintaining almost the same BER of the FC codebook. As a third contribution, this paper proposes a new codeword selection criteria based on Long term statistics of the CSI (LCSI), instead of the conventional criteria using instantaneous CSI. This reduces the feedback rate of the index of the selected codeword while providing performance improvement over non-precoded SSK. Simulation results show the effectiveness of the proposed Codebooks and the performance improvement with LCSI selection criteria.
-
phase rotation codebook precoding for space shift keying mimo systems
International Conference on Mobile and Wireless Technology, 2017Co-Authors: Mohammed Alansi, S A Aljunid, Essam SourourAbstract:Transmit Precoding (TPC) techniques based on maximizing the Minimum Euclidean Distance (MED) of the received constellation have been proposed to improve the performance of Space Shift Keying (SSK) MIMO systems. These methods have limitations, including the necessity of full Channel State Information (CSI) at the transmitter, high complexity since they generate arbitrary precoders, and the requirement of infinite rate feedback channel. On the other hand, Codebook based precoding approach have the competency to tackle these difficulties. Hence, this paper proposes Full-Combination (FC) codebook with a systematic structure constructed based on Phase Rotation Precoding (PRP) where the CSI is known to the receiver only. Also, two effective Codebooks called Factorized Full-Combinations (FFC) and Statistically Filtered Full-Combinations (SFF) are designed to solve the exhaustive search problem in FC codebook needed to find the best codeword that maximizes MED. Results illustrate the considerable performance gain achieved through applying the FC codebook. In addition, we show the capability of FFC and SFF Codebooks to reduce the complexity and provide almost the same BER as FC codebook.