Lisi Jiang

Bio: Lisi Jiang is an academic researcher from Beijing University of Posts and Telecommunications. The author has contributed to research in topics: Throughput (business) & Cellular network. The author has an hindex of 5, co-authored 7 publications receiving 114 citations.

Challenges of System-Level Simulations and Performance Evaluation for 5G Wireless Networks

Abstract: With the evaluation and simulation of long-term evolution/4G cellular network and hot discussion about new technologies or network architecture for 5G, the appearance of simulation and evaluation guidelines for 5G is in urgent need This paper analyzes the challenges of building a simulation platform for 5G considering the emerging new technologies and network architectures Based on the overview of evaluation methodologies issued for 4G candidates, challenges in 5G evaluation are formulated Additionally, a cloud-based two-level framework of system-level simulator is proposed to validate the candidate technologies and fulfill the promising technology performance identified for 5G

Energy distribution method of system for simultaneous transmission of wireless information and energy

Abstract: The invention relates to the field of wireless communication technologies, in particular to an energy distribution method of a system for simultaneous transmission of wireless information and energy The energy distribution method comprises the following steps that: information interaction is carried out on a mobile terminal serving base station and peripheral base stations, and deployment density of nearby activity base stations is obtained; the base station carries out position estimation on a receiving end of a mobile terminal, position information is obtained and downlink channel state information is obtained through user feedback; a model is established based on a stochastic geometric theory, an optimization problem is established with coverage as a constraint condition, when all mobile terminals adopt a unified distribution ratio rho of information decoding to energy harvesting, an optimal solution rhoa of a maximized average collection energy is solved; the rhoa is taken as a parameter, optimization is carried out on the distribution ratio rho of information decoding to energy harvesting based on a position of a mobile user, and a computed result is fed back to the mobile terminal; and the distribution ratio rho of information decoding to energy harvesting is provided by the mobile terminal according to instructions of the base station

Game-theoretic hierarchical resource allocation in ultra-dense networks

Abstract: Ultra-dense networks (UDN) can increase the network coverage and improve the overall throughput which make it a promising network technology. However, traditional resource allocation algorithms are concerned with the improvement of the overall performance of the network. This paper considers the quality of service (QoS) and energy consumption of each femtocell and proposes a game-theoretic hierarchical resource allocation algorithm in UDN. Firstly, a modified clustering algorithm is performed. Then we transform this resource allocation problem to a two-stage Stackelberg game. In sub-channel resource allocation, we aim to maximize the throughput of the whole system by cluster heads (CHs). The power allocation takes account of the balance between QoS requirement and transmit power consumption. Simulation results show that the proposed algorithm can obtain a performance improvement compared with other algorithms.

Kronecker product-based codebook design and optimisation for correlated 3D channels

Abstract: Discrete Fourier transform DFT codebook has been favoured by long term evolution because of its simplicity and effectiveness for two-dimensional multi-input multi-output channels. In order to further explore vertical freedom, a Kronecker product-based codebook KPC, which is the Kronecker product of a horizontal DFT codebook and a vertical one, has been proposed. However, how to effectively design the codebook is still a challenge, because neither its effectiveness nor optimisation has been studied. In this paper, we demonstrate that the codewords in the KPC approximately match the distribution of the optimal beamforming vectors under spatially correlated three-dimensional channels, showing the effectiveness of such codebook structure. Moreover, because the maximal cross-correlation amplitude Imax of the original KPC is high, we investigate the structure of the codebook and then find a criterion of constructing the optimal KPC to achieve the lowest Imax, namely the Welch bound. Furthermore, considering the optimal codebook only exists under certain conditions, a modified discrete stochastic approximation algorithm is used to construct a near-optimal codebook. Simulation results show that our algorithm greatly reduces Imax and respectively provides 1 and 0.5dB coding gain compared to the traditional DFT codebook and the original KPC, which confirms the efficiency of the codebook design. Copyright © 2014 John Wiley & Sons, Ltd.

Improved sparse channel estimation for multi-user massive MIMO systems with compressive sensing

Abstract: Massive multiple input multiple output (MIMO) is a promising technology for the next generation communication system to increase data rate and throughput. To fully enhance the performance of massive MIMO and improve the quality of service, accurate channel state information (CSI) is required for coherent detection. However, due to the overwhelming pilot overhead, conventional pilot aided channel estimation (PACE) approaches are not suitable for massive MIMO systems, especially for frequency-division duplexing (FDD) systems. In this paper, we consider the channel estimation problem in FDD multiuser massive MIMO systems. A spatial correlated channel is first modeled. By exploiting the spatial correlation, the channel can be represented in a sparse form in spatial-frequency domain. Then, the theory of compressive sensing (CS) is applied to develop an effective method for channel estimation. Moreover, based on the inherent common sparsity in the user channel matrices, this paper proposes an improved sparse channel estimation orthogonal matching pursuit (OMP) algorithm to reduce the pilot overhead and improve the channel estimation accuracy. Simulation results demonstrate that the proposed algorithm can significantly reduce the pilot overhead and have the superior performance in greatly elevating the accuracy of channel estimation.

A Survey on 5G Usage Scenarios and Traffic Models

Abstract: The fifth-generation mobile initiative, 5G, is a tremendous and collective effort to specify, standardize, design, manufacture, and deploy the next cellular network generation. 5G networks will support demanding services such as enhanced Mobile Broadband, Ultra-Reliable and Low Latency Communications and massive Machine-Type Communications, which will require data rates of tens of Gbps, latencies of few milliseconds and connection densities of millions of devices per square kilometer. This survey presents the most significant use cases expected for 5G including their corresponding scenarios and traffic models. First, the paper analyzes the characteristics and requirements for 5G communications, considering aspects such as traffic volume, network deployments, and main performance targets. Secondly, emphasizing the definition of performance evaluation criteria for 5G technologies, the paper reviews related proposals from principal standards development organizations and industry alliances. Finally, well-defined and significant 5G use cases are provided. As a result, these guidelines will help and ease the performance evaluation of current and future 5G innovations, as well as the dimensioning of 5G future deployments.

The Design of CMOS Radio-Frequency Integrated Circuits: RF CIRCUITS THROUGH THE AGES

Abstract: This expanded and thoroughly revised edition of Thomas H. Lee's acclaimed guide to the design of gigahertz RF integrated circuits features a completely new chapter on the principles of wireless systems. The chapters on low-noise amplifiers, oscillators and phase noise have been significantly expanded as well. The chapter on architectures now contains several examples of complete chip designs that bring together all the various theoretical and practical elements involved in producing a prototype chip. First Edition Hb (1998): 0-521-63061-4 First Edition Pb (1998); 0-521-63922-0

Enabling Technologies for Ultra-Reliable and Low Latency Communications: From PHY and MAC Layer Perspectives

Abstract: Future 5th generation networks are expected to enable three key services—enhanced mobile broadband, massive machine type communications and ultra-reliable and low latency communications (URLLC). As per the 3rd generation partnership project URLLC requirements, it is expected that the reliability of one transmission of a 32 byte packet will be at least 99.999% and the latency will be at most 1 ms. This unprecedented level of reliability and latency will yield various new applications, such as smart grids, industrial automation and intelligent transport systems. In this survey we present potential future URLLC applications, and summarize the corresponding reliability and latency requirements. We provide a comprehensive discussion on physical (PHY) and medium access control (MAC) layer techniques that enable URLLC, addressing both licensed and unlicensed bands. This paper evaluates the relevant PHY and MAC techniques for their ability to improve the reliability and reduce the latency. We identify that enabling long-term evolution to coexist in the unlicensed spectrum is also a potential enabler of URLLC in the unlicensed band, and provide numerical evaluations. Lastly, this paper discusses the potential future research directions and challenges in achieving the URLLC requirements.

Resource Allocation for Ultra-Dense Networks: A Survey, Some Research Issues and Challenges

Abstract: Driven by the explosive data traffic and new quality of service requirement of mobile users, the communication industry has been experiencing a new evolution by means of network infrastructure densification. With the increase of the density as well as the variety of access points (APs), the network benefits from proximal transmissions and increased spatial reuse of system resources, thus introducing a new paradigm named ultra-dense networks (UDNs). Since the limited available resources are shared by ubiquitous APs in UDNs, the demand for efficient resource allocation schemes becomes even more compelling. However, the large scale of UDNs impedes the exploration of effective resource allocation approaches particularly on the computational complexity and significance overhead or feedback. In this paper, we provide a survey-style introduction to resource allocation approaches in UDNs. Specifically, we first present some common scenarios of UDNs with the relevant special issues. Second, we provide a taxonomy to classify the resource allocation methods in the existing literatures. Then, to alleviate the main difficulties of UDNs, some prevailing and feasible solutions are elaborated. Next, we present some emerging technologies thriving UDNs with special RA features discussed. Additionally, the challenges and open research directions are outlined in this field.

Hybrid Peak-to-Average Power Ratio Reduction Techniques: Review and Performance Comparison

Abstract: Orthogonal frequency division multiplexing (OFDM) is an efficient multi-carrier modulation technique for wireless communication. However, one of the main drawbacks encountered in implementing it is its resultant high peak-to-average power ratio (PAPR). Many techniques have been proposed in the literature to substantially decrease the peaks in the OFDM signal. The problem with these, however, is that their effects on other parameters are not always positive. These effects include a decrease in the bit error rate (BER), an increase in complexity, or a reduction in the bit rate. The objective of this paper is to describe the PAPR problem in a bid to reduce the peaks in the OFDM signal. The paper proposes a classification, performance evaluation and optimization of PAPR reduction techniques for commercial, public safety, and tactical applications. In the taxonomy proposed herein, we also include a new category, namely, hybrid techniques. Furthermore, we compare the principal characteristics through a complementary cumulative distribution function and BER evaluation, and conclude on the importance of hybrid techniques, when the goal is to both improve the BER and reduce the PAPR.