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Your search keyword '"Zhao, Lian"' showing total 34 results
Start Over Author "Zhao, Lian" Journal ieee transactions on vehicular technology
34 results on '"Zhao, Lian"'

5. Integrated Sensing and Communication in mmWave Wireless Backhaul Networks

Author

Cui, Yue, Ding, Haichuan, Ke, Sheng, and Zhao, Lian

Abstract

Integrated sensing and communication (ISAC) becomes prevailing in wireless communications since it fully exploits the spectrum resources by incorporating data transmission and potential sensing functionalities of radio networks. With large bandwidth and directional communication, millimeter wave has the potentials for high data-rate communications and favorable time and spatial domain resolution, which can provide extensive sensing functionalities if properly utilized. Since self-backhauling at mmWave bands is considered a promising technology to enable high-throughput networks, we investigate how to embed ISAC functions into mmWave network by jointly considering high-speed data transmissions and high accuracy localization. To maximize the utilization of mmWave BSs for sensing and communication, we study the problem of optimal sensing task allocation taking into account target location, the requirements of different sensing tasks, user distribution, link scheduling, and data routing. With ISAC operations in mind, we analyze the time needed to complete each sensing task to facilitate problem formulation. To overcome the computational complexity in solution finding, we propose a sensing-oriented column generation (SOCG) scheme, which is shown to achieve near optimal performance via extensive performance evaluation. Furthermore, evaluation results demonstrate that the obtained sensing task allocation provides good throughput performance while ensuring the requirements of sensing tasks are satisfied.

Published
2024
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11. Least squares approximations to lognormal sum distributions

Author

Zhao, Lian and Ding, Jiu

Subjects
Approximation theory -- Analysis, Least squares -- Analysis, Lognormal distribution -- Analysis, Business, Electronics, Electronics and electrical industries, Transportation industry
Abstract

In this paper, the least squares (LS) approximation approach is applied to solve the approximation problem of a sum of lognormal random variables (RVs). The LS linear approximation is based on the widely accepted assumption that the sum of lognormal RVs can be approximated by a lognormal RV. We further derive the solution for the LS quadratic (LSQ) approximation, and our results show that the LSQ approximation exhibits an excellent match with the simulation results in a wide range of the distributions of the summands. Using the coefficients obtained from the LSQ method, we present the explicit closed-form expressions of the coefficients as a function of the decibel spread and the number of the summands by applying an LS curve fitting technique. Closed-form expressions for the cumulative distribution function and the probability density function for the sum RV, in both the linear and logarithm domains, are presented. Index Terms--Cumulative distribution functions (CDF), curve fitting, [L.sup.2]-norm, least squares (LS) linear/quadratic approximations, lognormal random variables (RVs), probability density function (pdf).

Published
2007

34. Distributed Multichannel and Mobility-Aware Cluster-Based MAC Protocol for Vehicular Ad Hoc Networks.

Author

Hafeez, Khalid Abdel, Zhao, Lian, Mark, Jon W., Shen, Xuemin, and Niu, Zhisheng

Subjects
*VEHICULAR ad hoc networks, *COMPUTER networks, *FUZZY logic, *COMMUNICATION, *WIRELESS communications, *IEEE 802.11 (Standard)
Abstract

Since vehicular safety applications require periodic dissemination of status and emergency messages, contention-based medium-access-control (MAC) protocols such as IEEE 802.11p have problems in predictability, fairness, low throughput, latency, and high collision rate, particularly in high-density networks. Therefore, a distributed multichannel and mobility-aware cluster-based MAC (DMMAC) protocol is proposed. Through channel scheduling and an adaptive learning mechanism integrated within the fuzzy-logic inference system (FIS), vehicles organize themselves into more stable and nonoverlapped clusters. Each cluster will use a different subchannel from its neighbors in a distributed manner to eliminate the hidden terminal problem. Increasing the system's reliability, reducing the time delay for vehicular safety applications, and efficiently clustering vehicles in highly dynamic and dense networks in a distributed manner are the main contributions of the proposed MAC protocol. The reliability and connectivity of DMMAC are analyzed in terms of the average cluster size, the communication range within the cluster and between cluster heads (CHs), and the lifetime of a path. Simulation results show that the proposed protocol can support traffic safety and increase vehicular ad hoc networks' (VANETs) efficiency, reliability, and stability of the cluster topology by increasing the CH's lifetime and the dwell time of its members. [ABSTRACT FROM PUBLISHER]

Published
2013
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