556 research outputs found
AWEQ: Post-Training Quantization with Activation-Weight Equalization for Large Language Models
Large language models(LLMs) exhibit excellent performance across a variety of
tasks, but they come with significant computational and storage costs.
Quantizing these models is an effective way to alleviate this issue. However,
existing methods struggle to strike a balance between model accuracy and
hardware efficiency. This is where we introduce AWEQ, a post-training method
that requires no additional training overhead. AWEQ excels in both
ultra-low-bit quantization and 8-bit weight and activation (W8A8) quantization.
There is an observation that weight quantization is less challenging than
activation quantization. AWEQ transfers the difficulty of activation
quantization to weights using channel equalization, achieving a balance between
the quantization difficulties of both, and thereby maximizing performance. We
have further refined the equalization method to mitigate quantization bias
error, ensuring the robustness of the model. Extensive experiments on popular
models such as LLaMA and OPT demonstrate that AWEQ outperforms all existing
post-training quantization methods for large models
Uniform bound and a non-existence result for Lichnerowicz equation in the whole <i>n</i>-space
IRS-aided UAV for Future Wireless Communications: A Survey and Research Opportunities
Both unmanned aerial vehicles (UAVs) and intelligent reflecting surfaces
(IRS) are gaining traction as transformative technologies for upcoming wireless
networks. The IRS-aided UAV communication, which introduces IRSs into UAV
communications, has emerged in an effort to improve the system performance
while also overcoming UAV communication constraints and issues. The purpose of
this paper is to provide a comprehensive overview of IRSassisted UAV
communications. First, we provide five examples of how IRSs and UAVs can be
combined to achieve unrivaled potential in difficult situations. The
technological features of the most recent relevant researches on IRS-aided UAV
communications from the perspective of the main performance criteria, i.e.,
energy efficiency, security, spectral efficiency, etc. Additionally, previous
research studies on technology adoption as machine learning algorithms. Lastly,
some promising research directions and open challenges for IRS-aided UAV
communication are presented
A Deterministic Construction for Jointly Designed Quasicyclic LDPC Coded-Relay Cooperation
This correspondence presents a jointly designed quasicyclic (QC) low-density parity-check (LDPC) coded-relay cooperation with joint-iterative decoding in the destination node. Firstly, a design-theoretic construction of QC-LDPC codes based on a combinatoric design approach known as optical orthogonal codes (OOC) is presented. Proposed OOC-based construction gives three classes of binary QC-LDPC codes with no length-4 cycles by utilizing some known ingredients including binary matrix dispersion of elements of finite field, incidence matrices, and circulant decomposition. Secondly, the proposed OOC-based construction gives an effective method to jointly design length-4 cycles free QC-LDPC codes for coded-relay cooperation, where sum-product algorithm- (SPA-) based joint-iterative decoding is used to decode the corrupted sequences coming from the source or relay nodes in different time frames over constituent Rayleigh fading channels. Based on the theoretical analysis and simulation results, proposed QC-LDPC coded-relay cooperations outperform their competitors under same conditions over the Rayleigh fading channel with additive white Gaussian noise
I/Q Imbalance and Imperfect SIC on Two-way Relay NOMA Systems
Abstract: Non-orthogonal multiple access (NOMA) system can meet the demands of ultra-high data rate, ultra-low latency, ultra-high reliability and massive connectivity of user devices (UE). However, the performance of the NOMA system may be deteriorated by the hardware impairments. In this paper, the joint effects of in-phase and quadrature-phase imbalance (IQI) and imperfect successive interference cancellation (ipSIC) on the performance of two-way relay cooperative NOMA (TWR C-NOMA) networks over the Rician fading channels are studied, where two users exchange information via a decode-and-forward (DF) relay. In order to evaluate the performance of the considered network, analytical expressions for the outage probability of the two users, as well as the overall system throughput are derived. To obtain more insights, the asymptotic outage performance in the high signal-to-noise ratio (SNR) region and the diversity order are analysed and discussed. Throughout the paper, Monte Carlo simulations are provided to verify the accuracy of our analysis. The results show that IQI and ipSIC have significant deleterious effects on the outage performance. It is also demonstrated that the outage behaviours of the conventional OMA approach are worse than those of NOMA. In addition, it is found that residual interference signals (IS) can result in error floors for the outage probability and zero diversity orders. Finally, the system throughput can be limited by IQI and ipSIC, and the system throughput converges to a fixed constant in the high SNR region
Outage Performance of Fluid Antenna System (FAS)-aided Terahertz Communication Networks
Millimeter-wave networks have already been successfully rolled out in many
countries and now the research direction heads toward new technologies and
standards to enable Tbps rates for future sixth-generation (6G) wireless
communication systems. This work studies a point-to-point terahertz (THz)
communication network exploiting the concept of a fluid antenna system (FAS)
over correlated alpha-mu fading channels, nicely fitting the THz communication.
Furthermore, the considered system is expanded to the selection-combining-FAS
(SC-FAS) and maximum-gain-combining- FAS (MGC-FAS) diversity variates at the
receiver side. The proposed FAS and its diversity configuration techniques are
aimed to combat the high path loss, blockages, and molecular absorption effect
related to the THz band. Our contribution includes comprehensive outage
probability (OP) performance analysis for the THz band given the non-diversity
and diversity FAS receivers. Moreover, the derived outage probability formulas
are verified via Monte Carlo simulations. Numerical results have confirmed the
superior performance of the MGC-FAS scheme in terms of OP. Finally, this work
justifies that a higher number of antenna ports dramatically improves the
system performance, even in the presence of correlation.Comment: Accepted for Presentation at IEEE ICC 2023 (Rome, Italy), 6 pages, 5
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Resource Allocation for Multicarrier Rate-Splitting Multiple Access System
In this article, we investigate the resource allocation problem for the multicarrier rate-splitting multiple access (RSMA) systems. On each subcarrier, messages are non-orthogonal superimposed on the power domain through the one-layer RSMA scheme. A novel three-step resource allocation algorithm is proposed to deal with the non-convex problem of sum rate maximization. In step 1, assuming average power allocation among subcarriers, we obtain the power distribution factors of the users in a single subcarrier by converting this problem into a difference of convex program (DCP), and approximate it by its first-order Taylor expansion. In step 2, we convert the user-subcarrier matching problem into an assignment problem and use the Hungarian algorithm to solve it. In step 3, the optimized power allocation algorithm is used to calculate the power allocation among the subcarriers, and then updates the power vector for each user. Numerical results show that our proposed three-step resource allocation algorithm could achieve comparable sum rate performance to the existing near-optimal solution with much lower computational complexity and outperforms orthogonal multiple access (OMA) scheme
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