检索结果-内蒙古大学图书馆

Optimized layered multicast with superposition coding in cellular systems

WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2012年第13期12卷 1147-1156页

作者： Liu, Yang Wang, Wenbo Peng, Mugen Zhu, Song Beijing Univ Posts & Telecommun Wireless Signal Proc & Network Lab Minist Educ Key Lab Universal Wireless Commun Beijing 100876 Peoples R China

We consider the problem of optimal power allocation and optimal user selection in a layered multicast transmission over quasi-static Rayleigh fading channels. A scheme based on superposition coding is proposed in which basic multicast streams and enhanced multicast streams are superimposed and transmitted by a base station, while users with worse channel conditions can only decode basic multicast streams, and users with better channel conditions can decode both basic and enhanced multicast streams. In this paper, subject to fixed user selection ratios, the optimal power allocation for each stream that maximizes average throughput is investigated, and the impact of power allocation on average outage probability is discussed. Finally, subject to fixed transmit power and power allocation, the optimal user selection ratio for enhanced multicast streams is also studied. Numerical results show that the optimized layered multicast scheme outperforms the conventional multicast scheme in terms of average throughput. Copyright (c) 2010 John Wiley & Sons, Ltd.

关键词： superposition coding layered multicast power allocation user selection ratio

来源：评论

学校读者我要写书评

暂无评论

Pairwise Transmission Using superposition coding for Relay-Assisted Downlink Communications

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2015年第5期14卷 2788-2801页

作者： Shi, Sulong Yang, Longxiang Zhu, Hongbo Nanjing Univ Posts & Telecommun Coll Telecommun & Informat Engn Nanjing 210003 Peoples R China

We consider the downlink relay network, for which a pairwise transmission strategy is suggested with the users being grouped into pairs and the source communicating to each pair of users using a novel pairwise relaying protocol. By utilizing superposition coding (SC), the messages of each two paired users are intentionally transmitted non-orthogonally or simultaneously in the same time-frequency channel to compensate for the bandwidth loss of relaying. We investigate the optimal decoding at the relay and the users, respectively, which are then combined to guide the selection of the power allocation factors of SC and to decide the corresponding decoding order. Then, a largely simplified outage expression of the pairwise relaying protocol is given, based on which we investigate, for the multi-user scenarios, the user pairing problem from the perspective of minimizing the total power consumption under targeted outage probabilities of the users. An easily implemented user pairing algorithm with computational complexity of O(K-2) is provided, which achieves a performance that is very close to that of the optimal user pairing which can be solved in polynomial time, O(K-3). Numerical results show that the pairwise transmission strategy can significantly decrease the average transmit power.

关键词： Downlink relay fading channel decode-and-forward superposition coding user pairing

来源：评论

学校读者我要写书评

暂无评论

Optimal joint rate and power allocation for layered multicast with superposition coding in cellular systems

引用

WIRELESS NETWORKS 2013年第1期19卷 69-81页

作者： Liu, Yang Wang, Wenbo Peng, Mugen Wei, Dongyan Beijing Univ Posts & Telecommun Minist Educ Key Lab Universal Wireless Commun Beijing 100876 Peoples R China Chinese Acad Sci Beijing Peoples R China

We propose a layered multicast transmission scheme with superposition coding for cellular systems, i.e., at a base station a basic multicast stream (BMS) and an enhanced multicast stream (EMS) are superimposed and transmitted, the same BMS is repeatedly transmitted multiple times to ensure most users in the cell receive basic qualities of the service, while in each transmission different EMSs are transmitted to make the users with good channel conditions receive higher qualities of the service. In this paper, the optimal joint rate and power allocation for the layered multicast scheme is studied. Specifically, we first give a proof on the claim that the system delay of a BMS is minimized if the transmission rate of the BMS is set according to a fixed user selection ratio in each transmission. Then subject to fixed transmit power and power allocation, we derive the optimal transmission rate of a BMS that minimizes the system delay of the BMS, and the optimal transmission rate of an EMS that maximizes the average throughput of the EMS. Finally, by balancing the tradeoff between the system delay of a BMS and the average throughput of an EMS, we find the optimal joint rate and power allocation for the layered multicast scheme. Numerical results show that the optimized layered multicast scheme outperforms the conventional schemes in terms of the system delay of a BMS and the average throughput of an EMS.

关键词： superposition coding Layered multicast Rate Power allocation User selection ratio

来源：评论

学校读者我要写书评

暂无评论

Throughput Maximization for Cognitive Radio Networks Using Active Cooperation and superposition coding

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2015年第6期14卷 3322-3336页

作者： Hamza, Doha Park, Ki-Hong Alouini, Mohamed-Slim Aissa, Sonia KAUST Comp Elect & Math Sci & Engn CEMSE Div Thuwal 239556900 Saudi Arabia Univ Quebec Inst Natl Rech Sci INRS EMT Montreal PQ G1K 9A9 Canada

We propose a three-message superposition coding scheme in a cognitive radio relay network exploiting active cooperation between primary and secondary users. The primary user is motivated to cooperate by substantial benefits it can reap from this access scenario. Specifically, the time resource is split into three transmission phases. The first two phases are dedicated to primary communication, while the third phase is for the secondary's transmission. We formulate two throughput maximization problems for the secondary network subject to primary user rate constraints and per-node power constraints with respect to the time durations of primary transmission and the transmit power of the primary and the secondary users. The first throughput maximization problem assumes a partial power constraint such that the secondary power dedicated to primary cooperation, i.e. for the first two communication phases, is fixed apriori. In the second throughput maximization problem, a total power constraint is assumed over the three phases of communication. The two problems are difficult to solve analytically when the relaying channel gains are strictly greater than each other and strictly greater than the direct link channel gain. However, mathematically tractable lowerbound and upperbound solutions can be attained for the two problems. For both problems, by only using the lowerbound solution, we demonstrate significant throughput gains for both the primary and the secondary users through this active cooperation scheme. We find that most of the throughput gains come from minimizing the second phase transmission time since the secondary nodes assist the primary communication during this phase. Finally, we demonstrate the superiority of our proposed scheme compared to a number of reference schemes that include best relay selection, dual-hop routing, and an interference channel model.

关键词： Cognitive radio networks cognitive relaying decode-and-forward relaying superposition coding active cooperation

来源：评论

学校读者我要写书评

暂无评论

Proportional fair scheduling with superposition coding in a cellular cooperative relay system

引用

ANNALS OF TELECOMMUNICATIONS-ANNALES DES TELECOMMUNICATIONS 2013年第9-10期68卷 525-537页

作者： Kaneko, Megumi Hayashi, Kazunori Popovski, Petar Sakai, Hideaki Kyoto Univ Grad Sch Informat Sakyo Ku Kyoto 6068501 Japan Aalborg Univ Dept Elect Syst DK-9220 Aalborg Denmark

Many works have tackled on the problem of throughput and fairness optimization in cellular cooperative relaying systems. Considering firstly a two-user relay broadcast channel, we design a scheme based on superposition coding (SC) which maximizes the achievable sum-rate under a proportional fairness constraint. Unlike most relaying schemes where users are allocated orthogonally, our scheme serves the two users simultaneously on the same time-frequency resource unit by superposing their messages into three SC layers. The optimal power allocation parameters of each SC layer are derived by analysis. Next, we consider the general multi-user case in a cellular relay system, for which we design resource allocation algorithms based on proportional fair scheduling exploiting the proposed SC-based scheme. Numerical results show that the proposed algorithms allowing simultaneous user allocation outperform conventional schedulers based on orthogonal user allocation, both in terms of throughput and proportional fairness. These results indicate promising new directions for the design of future radio resource allocation and scheduling algorithms.

关键词： Cellular relay system Cooperative communication superposition coding Proportional fair scheduling

来源：评论

学校读者我要写书评

暂无评论

Optimality of Simple Layered superposition coding in the 3 User MISO BC With Finite Precision CSIT

引用

IEEE TRANSACTIONS ON INFORMATION THEORY 2019年第11期65卷 7181-7207页

作者： Davoodi, Arash Gholami Jafar, Syed Univ Calif Irvine Dept Elect Engn & Comp Sci CPCC Irvine CA 92697 USA

We study the K = 3 user multiple input single output (MISO) broadcast channel (BC) with M = 3 antennas at the transmitter and 1 antenna at each receiver, from the generalized degrees of freedom (GDoF) perspective, under the assumption that the channel state information at the transmitter (CSIT) is limited to the finite precision. In particular, our goal is to identify a parameter regime where a simple layered superposition (SLS) coding scheme achieves the entire GDoF region. With alpha(ij) representing the channel strength parameter for the link from the j(th) antenna of the transmitter to the i(th) receiver, we prove that the SLS is GDoF optimal without the need for time-sharing if max(alpha(ki), alpha(im)) <= alpha(ii) and alpha(ki) + alpha(im) <= alpha(ii) + alpha(km) for all i, k is an element of [3], m is an element of [M]. The GDoF region under this condition is a convex polyhedron. The result generalizes to arbitrary M >= 3.

关键词： Broadcast channel superposition coding finite precision channel state information at transmitters

来源：评论

学校读者我要写书评

暂无评论

Cooperative Relaying of superposition coding with Simple Feedback for Layered Source Transmission

引用

IEEE TRANSACTIONS ON COMMUNICATIONS 2013年第11期61卷 4448-4461页

作者： Wang, Jin Soo Kim, Yun Hee Song, Iickho Cosman, Pamela C. Milstein, Laurence B. Kyung Hee Univ Dept Elect & Radio Engn Yongin 446701 Gyeonggi South Korea Korea Adv Inst Sci & Technol Dept Elect Engn Taejon 305701 South Korea Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

We consider a relay network that delivers a Gaussian source by employing successive refinement source coding and superposition coding of layers at the source node and successive decoding at the relay and destination nodes. For the network, making use of the decoding results at the relay and destination nodes of the first transmission, an efficient relaying strategy of layers is proposed to minimize the expected distortion (ED) when only the average channel state information is available at the source node. Three types of the proposed scheme, defined as Prop-DF, using decode-and-forward signals, Prop-AF, using amplify-and-forward signals, and Prop-MF, using mixed-forward signals, are addressed and analyzed in terms of the outage probability and distortion exponent. Unlike other studies, we have also taken the relay location into account in deriving the distortion exponent showing the high SNR behavior of the ED. The results show that the proposed scheme increases the distortion exponent up to twice that of the conventional relaying schemes when the relay is close to the source node, and that Prop-MF provides the best performance for most relay locations.

关键词： superposition coding Amplify-and-forward Decode-and-forward Expected distortion Distortion exponent

来源：评论

学校读者我要写书评

暂无评论

A Unified Treatment of superposition coding Aided Communications: Theory and Practice

引用

IEEE COMMUNICATIONS SURVEYS AND TUTORIALS 2011年第3期13卷 503-520页

作者： Zhang, Rong Hanzo, Lajos Univ Southampton Sch ECS Southampton SO17 1BJ Hants England

In this tutorial, a unified treatment of the topic of superposition coding (SPC) aided communications systems is offered, where we focus our attention not only on the theoretical background of SPC but also on its implementation techniques. The design methodology of SPC aided communications transceivers is described, including the Multiple Level Modulation (MLM) concept, the corresponding iterative Successive Interference Cancellation (SIC) aided receiver and the quasi-random coding principle. Building on these fundamental discussions, various future wireless applications of the SPC technique were provided, which encompass cooperative communications-assisted relay systems and cross-layer SPC aided multiplexed Hybrid Automatic Repeat reQuest (HARQ) techniques. Our discussions demonstrate that the SPC technique is a promising enabler for diverse future wireless communications scenarios, ranging from cellular networks to cooperative networks.

关键词： superposition coding turbo receiver quasi-random coding cooperative communications HARQ

来源：评论

学校读者我要写书评

暂无评论

Cross-Layer Design Using superposition coding Scheme for Multiuser OFDM Systems

引用

WIRELESS PERSONAL COMMUNICATIONS 2013年第2期71卷 1339-1352页

作者： Goyal, Kalpana Trivedi, Aditya Maulana Azad Natl Inst Technol Bhopal MP India ABV Indian Inst Informat Technol & Management ICT Dept Gwalior MP India

In this paper, a cross-layer design is proposed for downlink of orthogonal frequency division multiplexing systems which uses superposition coding (SC) scheme. SC theorem allows two users to share the same subchannel. Firstly, the subchannel will be allocated to degraded user (who is far away from the base station) and then this subchannel will be allowed to be shared by potential user (who is near to the base station). We also employed a packet dependent scheduling at the medium access control layer which decides the transmission order of packets according to the delay, size and quality of service priority level of packets. The weight of each user can be calculated by summing up the weights of all packets in the queues of that user. We have considered that each user is having multiple heterogeneous traffic queues. Simulation results show that the algorithm proposed in this paper is better than the previously reported algorithm in terms of total throughput and packet delay with the same computational complexity.

关键词： Cross-layer design OFDM Dynamic resource allocation superposition coding Packet scheduling Quality of service (QoS)

来源：评论

学校读者我要写书评

暂无评论

Study of SISO superposition coding Performance From Improper Discrete Signaling Perspective

引用

IEEE WIRELESS COMMUNICATIONS LETTERS 2024年第3期13卷 884-888页

作者： Pendas-Recondo, Alvaro Lopez-Fernandez, Jesus Alberto Ayestaran, Rafael Gonzalez Univ Oviedo Grp Signal Theory & Commun Dept Elect Engn Gijon Spain

A study of interference management in a Single-Input-Single-Output (SISO) two-user broadcast scenario by adjusting the circularity coefficient of discrete constellations is presented. Previously researched techniques for the same problem, namely the combination of PAM and QAM constellations, are reviewed as instances of the improper approach. The presented investigation further extends to the exploration of other combinations. Remarkably, all results presented in this letter are based on figures of merit of discrete constellations (mutual information, error probability, and minimum distance between symbols) rather than on formulas extrapolated from Gaussian signaling. Findings indicate that certain conclusions drawn previously for Improper Gaussian Signaling (IGS) in a similar setting hold for finite input constellations, though some vary.

关键词： Symbols Mutual information Quadrature amplitude modulation Standards Resource management Receivers Random variables Improper signaling discrete constellations interference channel superposition coding

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：