检索结果-内蒙古大学图书馆

Localized Power Control for Multihop Large-Scale Internet of Things

IEEE INTERNET OF THINGS JOURNAL 2016年第4期3卷 503-510页

作者： Bader, Ahmed Alouini, Mohamed-Slim KAUST CEMSE Dept Thuwal 239556900 Makkah Province Saudi Arabia

In this paper, we promote the use of multihop networking in the context of large-scale Internet of Things (IoT). Recognizing concerns related to the scalability of classical multihop routing and medium access techniques, we advocate the use of blind cooperation in conjunction with multihop communications. However, we show that blind cooperation is actually inefficient unless power control is applied. Inefficiency in this paper is projected in terms of the transport rate normalized to energy consumption. To that end, we propose an uncoordinated power control mechanism whereby each device in a blind cooperative cluster randomly adjusts its transmit power level. We derive an upper bound on the mean transmit power that must be observed at each device. We also devise a practical mechanism for each device to infer about the size of its neighborhood, a requirement necessary for the operation of the power control scheme. Finally, we assess the performance of the developed power control mechanism and demonstrate how it consistently outperforms the point-to-point case.

关键词： Blind cooperative transmission distributed array gain large-scale Internet of Things (IoT) localized power control multi-hop networking

来源：评论

学校读者我要写书评

暂无评论

Joint Design of Multiple Non-Regenerative MIMO Relaying Matrices With Power Constraints

引用

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2013年第19期61卷 4861-4873页

作者： Zhao, Chao Champagne, Benoit McGill Univ Dept Elect & Comp Engn Montreal PQ H3A 0E9 Canada

This paper investigates the joint design of multiple non-regenerative multiple-input multiple-output (MIMO) relaying matrices, with the purpose of minimizing the mean square error (MSE) between the transmitted signals from the source and the received signals at the destination. Two types of constraints on the transmit power of the relays are considered separately: 1) a weighted sum power constraint, and 2) per-relay power constraints. As opposed to using general-purpose interior-point methods, we exploit the inherent structure of the problems to develop more efficient algorithms. Under the weighted sum power constraint, the optimal solution is expressed as a function of a Lagrangian parameter. By introducing a complex scaling factor at the destination, we derive a closed-form expression for this parameter, thereby avoiding the need to solve an implicit nonlinear equation numerically. Under the per-relay power constraints, the optimal solution is the same as that under the weighted sum power constraint if particular weights are chosen. We then propose an iterative power balancing algorithm to compute these weights. In addition, under both types of constraints, we investigate the joint design of a MIMO equalizer at the destination and the relaying matrices, using block coordinate descent or steepest descent. The bit-error rate (BER) simulation results demonstrate that all the proposed designs, under either type of constraints, with or without the equalizer, perform much better than previous methods.

关键词： distributed array gain MIMO MMSE non-regenerative power balancing relay

来源：评论

学校读者我要写书评

暂无评论

A Low-Complexity Hybrid Framework for Combining-Type Non-regenerative MIMO Relaying

引用

WIRELESS PERSONAL COMMUNICATIONS 2013年第1期72卷 635-652页

作者： Zhao, Chao Champagne, Benoit McGill Univ Dept Elect & Comp Engn Montreal PQ H3A 0E9 Canada

Combining-type relay systems can benefit from distributed array gain if the signals retransmitted from different relays are superimposed coherently at the destination. For this purpose, we propose a low-complexity hybrid framework in which the non-regenerative multiple-input-multiple-output relaying matrix at each relay is generated by cascading two substructures, akin to an equalizer for the backward channel and a precoder for the forward channel. For each of these two substructures, we introduced two one-dimensional parametric families of candidate matrix transformations. The first family, non-cooperative by nature, depends only on the backward or forward channel of the same relay. The second (cooperative) family also makes use of information derived from the channels of other relays. This hybrid framework allows for the classification and comparison of all possible combinations of these substructures, including several previously investigated methods and their generalizations. The design parameters can be optimized based on individual channel realizations or on channel statistics;in the latter case, the optimum parameters can be well approximated by linear functions of the signal-to-noise ratios. The proposed methods achieve a good balance between performance and complexity: they outperform existing low-complexity strategies by a large margin in terms of both capacity and bit-error rate, and at the same time, are significantly simpler than previous near-optimal iterative algorithms.

关键词： Combining-type distributed array gain Hybrid relaying MIMO Non-regenerative relaying

来源：评论

学校读者我要写书评

暂无评论

Relaying schemes using matrix triangularization for MIMO wireless networks

引用

IEEE TRANSACTIONS ON COMMUNICATIONS 2007年第9期55卷 1683-1688页

作者： Shi, Hui Abe, Tetsushi Asai, Takahiro Yoshino, Hitoshi NTT DoCoMo Res Labs Tokyo Japan DoCoMo Euro Lab Wireless Solut Labs Munich Germany

Multiple input multiple output (MIMO) relay networks are wireless communication systems comprising of multiple nodes, each of which is equipped with multiple antennas. Recent information theories have shown that using multiple nodes to simultaneously relay a message can improve the capacity of source-to-destination communications. In this paper, we propose new relaying schemes for MIMO relay networks. The major concept behind the proposed schemes is to transform each of the MIMO relay channels into an equivalent triangular channel with positive real diagonal entries. By doing so, the resultant MIMO relay channel can simultaneously offer both distributed array gain (diversity gain obtained among relay nodes) and intranode array gain (diversity gain realized by multiple antennas of individual relay node) while maintaining the maximum spatial multiplexing gain (number of parallel data pipes). Based on this concept, three relaying schemes are derived that perform QR decomposition and phase control. Numerical results confirm that at least one of the proposed schemes outperforms the amplify-and-forward and the zero-forcing relaying schemes under various conditions. Moreover, we show that ratios of noise power level at relay and destination node have a great impact on capacities.

关键词： distributed array gain intranode array gain phase control QR decomposition spatial multiplexing gain wireless networks

来源：评论

学校读者我要写书评

暂无评论

Analyses of achievable gains in half duplex MIMO relaying schemes using multiple relay nodes

Analyses of achievable gains in half duplex MIMO relaying sc...

引用

International Symposium on Antennas and Progagation

作者： Shi, Hui Abe, Tetsushi Asai, Takahiro Yoshino, Hitoshi DoCoMo Inc NTT Res Labs Yokosuka Kanagawa 2398536 Japan DoCoMo Commun Labs Europe GmbH Wireless Solut Labs Munich Germany

In multiple-input multiple-output (MIMO) wireless relay networks, simultaneously using multiple relay nodes can improve the capacity of source-to-destination communications. Recent information theories have shown that passing the same message across multiple relay nodes can improve the capacity of source-to-destination communications. We have previously proposed three relay schemes that use jointly QR decomposition and the phase control matrix;computer simulations have confirmed the superiority of these schemes over conventional ones such as amplify-and-forward and zero-forcing schemes. In this paper, we analyze the capacity and achievable gains (distributed array gain, intra-node array gain and spatial multiplexing gain) of the previously proposed relay schemes (QR-P-QR, QR-P-ZF, and ZF-P-QR) and thus provide an insight into what contributes to their superiority over conventional schemes. The analyses show that the location of the relay nodes used has a significant impact on capacity. On the basis of this observation, we further propose a method that enables each relay node to individually select its relay scheme according to its channel conditions so as to maximize the capacity. A computer simulation confirms the capacity improvement achieved by the proposed selection method.

关键词： MIMO wireless relay networks distributed array gain intranode array gain spatial multiplexing gain QR decomposition phase control

来源：评论

学校读者我要写书评

暂无评论

A relaying scheme using QR decomposition with phase control for MIMO wireless networks

A relaying scheme using QR decomposition with phase control ...

引用

IEEE International Conference on Communications (ICC 2005)

作者： Shi, H Abe, T Asai, T Yoshino, H Wireless Laboratories NTT DoCoMo Inc. Japan

ISBN: (纸本)0780389387

Multiple-input multiple-output (MIMO) wireless networks are wireless communication systems composed of multiple nodes, each of which is equipped with multiple antennas. As proven by earlier studies, point-to-point MIMO systems offer significant capacity through spatial multiplexing and diversity techniques. Furthermore, recent studies have shown that the capacity of MIMO wireless networks can be greatly improved by using multiple relay nodes to relay messages simultaneously from source to destination. This paper proposes a relaying scheme for MIMO wireless networks. Its major concepts are 1) performing QR decomposition on backward and forward channels in conjunction with phase control at each relay node, and 2) conducting successive interference cancellation (SIC) at the destination node. Such operations enable the wireless network to obtain distributed array gain among multiple relay nodes and receive array gain while maintaining maximum spatial multiplexing gain. Numerical examples have shown that the proposed relaying scheme is superior to previously proposed ones in both ergodic and outage capacity perspective.

关键词： MIMO wireless networks spatial multiplexing gain receive array gain distributed array gain QR decomposition phase control successive interference cancellation (SIC)

来源：评论

学校读者我要写书评

暂无评论

A relaying scheme for MIMO wireless networks with multiple source and destination pairs

A relaying scheme for MIMO wireless networks with multiple s...

引用

11th Asia-Pacific Conference on Communications

作者： Abe, T Shi, H Asai, T Yoshino, H Wireless Laboratories NTT DoCoMo Japan

ISBN: (纸本)0780391322

A multiple-input multiple-output (MIMO) relay network is composed of source, relay, and destination nodes, each of which is equipped with multiple antennas. Network information theory has shown that the use of multiple relay nodes in source and destination (S-D) communication makes the capacity of the S-D system logarithmically increase with the number of relay nodes. In [13], we proposed a MIMO relay scheme for a relay network with single source and destination pair;each of the multiple relay nodes performs QR decomposition of backward and forward channels in conjunction with phase control (QR-P-QR). In this paper, we extend this scheme to the MIMO relay network with multiple source and destination pairs. For this aim, We use the group nulling approach to decompose the multiple S-D MIMO relay channel to parallel independent S-D MIMO relay channels, and apply the QR-P-QR scheme in each of the decomposed MIMO relay links. Numerical examples show that the proposed relay scheme offers higher capacity than the existing zero-forcing (ZF) relaying scheme.

关键词： MIMO relay networks spatial multiplexing gain receive array gain distributed array gain group nulling QR decomposition phase control successive interferece cancellation (SIC)

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：