• The Journal of Asian Finance, Economics and Business
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• 제8권9호
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• pp.113-119
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• 2021

With the increasing pressure of international competition, urban agglomeration cooperation and innovation had become an important means of regional economic development. This study analyzed the spatial characteristics of the Urban Cooperative Innovation Network in Guangdong-Hong Kong-Macao Greater Bay Area, found out the dynamic evolution law of innovation, provided suggestions for policy management departments, and effectively planned the industrial layout. According to the data of the State Intellectual Property Office of China, this study researched invention patents from 2005 to 2019. This paper constructed the urban cooperative innovation network, and took 11 cities in the bay area as the research objects, and used social network analysis to study the spatial structure and dynamic evolution of the urban innovation network. Every indicator reflected the urban cooperative innovation, but they all showed a certain decline in 2008-2010. And it is inferred that the innovation network space of each city will be "obvious fist advantages, significant spillover effect and weakening role of Hong Kong and Macao". This paper divided urban cooperative innovation of Guangdong-Hong Kong-Macao Greater Bay Area into three stages. Summing up the characteristics of each stage is helpful to recognize the changes of urban cooperative innovation and to do a good job in industrial layout planning.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.956-958
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• 2010

The paper considers MIMO two-way scheme to optimize the end to end capacity in local wireless mesh network. The basic idea is to perform data transmission via intermediate cooperative nodes and cooperative relay therefore higher throughput can be achieved. Each node is equipped with multiple antennas, and has two time slots one for transmission (Tx) and the other is reception (Rx), which are arranged alternatively in the network. In the conventional SISO network, it takes at least four time slots to accomplish the function of two-way relay. Moreover, cooperative technique is used in order to enhance multiplexing of forward and backward streams.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4405-4418
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• 2015

Different network provides different service. To maximize the profit, heterogeneous networks form a whole, which may either compete or cooperate with each other. In this paper, the healthcare monitor network architecture is introduced to build the competitive and cooperative mechanisms of heterogeneous networks which contain three networks, namely, cellular network, WLAN and WMAN. This paper considers the natural growth rate of the network with competitive and cooperative effects. Then, the stability of the proposed model and its equilibrium points are analyzed by the ordinary differential principle. Finally, simulation results show that the natural growth rate cannot increase the profit of the network, but effective cooperative among heterogeneous networks can increase the profit of each network, and competitive may decrease the profit of each network.

• Journal of Communications and Networks
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• 제12권1호
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• pp.11-18
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• 2010

Diversity-multiplexing tradeoff (DMT) is an efficient tool to measure the performance of multiple-input and multiple-output (MIMO) systems and cooperative systems. Recently, cooperative multicast system with wireless network coding stretched tremendous interesting due to that it can drastically enhance the throughput of the wireless networks. It is desirable to apply DMT to the performance analysis on the multicast system with wireless network coding. In this paper, DMT is performed at the three proposed wireless network coding protocols, i.e., non-regenerative network coding (NRNC), regenerative complex field network coding (RCNC) and regenerative Galois field network coding (RGNC). The DMT analysis shows that under the same system performance, i.e., the same diversity gain, all the three network coding protocols outperform the traditional transmission scheme without network coding in terms of multiplexing gain. Our DMT analysis also exhibits the trends of the three network coding protocols' performance when multiplexing gain is changing from the lower region to the higher region. Monte-Carlo simulations verify the prediction of DMT.

• Journal of Communications and Networks
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• 제10권2호
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• pp.204-212
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• 2008

We study the routing problem in all-wireless networks based on cooperative transmissions. We model the minimum-energy cooperative path (MECP) problem and prove that this problem is NP-complete. We hence design an approximation algorithm called cooperative shortest path (CSP) algorithm that uses Dijkstra's algorithm as the basic building block and utilizes cooperative transmissions in the relaxation procedure. Compared with traditional non-cooperative shortest path algorithms, the CSP algorithm can achieve a higher energy saving and better balanced energy consumption among network nodes, especially when the network is in large scale. The nice features lead to a unique, scalable routing scheme that changes the high network density from the curse of congestion to the blessing of cooperative transmissions.

• Journal of Communications and Networks
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• 제13권3호
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• pp.266-276
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• 2011

In wireless networks, it is well-known that intermediate nodes can be used as cooperative relays to reduce the transmission energy required to reliably deliver a message to an intended destination. When the network is under a central authority, energy allocations and cooperative pairings can be assigned to optimize the overall energy efficiency of the network. In networks with autonomous selfish nodes, however, nodes may not be willing to expend energy to relay messages for others. This problem has been previously addressed through the development of extrinsic incentive mechanisms, e.g., virtual currency, or the insertion of altruistic nodes in the network to enforce cooperative behavior. This paper considers the problem of how selfish nodes can decide on an efficient energy allocation and endogenously form cooperative partnerships in wireless networks without extrinsic incentive mechanisms or altruistic nodes. Using tools from both cooperative and non-cooperative game theory, the three main contributions of this paper are (i) the development of Pareto-efficient cooperative energy allocations that can be agreed upon by selfish nodes, based on axiomatic bargaining techniques, (ii) the development of necessary and sufficient conditions under which "natural" cooperation is possible in systems with fading and non-fading channels without extrinsic incentive mechanisms or altruistic nodes, and (iii) the development of techniques to endogenously form cooperative partnerships without central control. Numerical results with orthogonal amplify-and-forward cooperation are also provided to quantify the energy efficiency of a wireless network with sources selfishly allocating transmission/relaying energy and endogenously forming cooperative partnerships with respect to a network with centrally optimized energy allocations and pairing assignments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권6호
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• pp.1668-1688
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• 2012

Cooperative communications and network coding schemes have been proposed to increase system throughput for ad hoc networks. In this paper, we present throughput and delay analysis of the new network coding-enabled cooperative MAC protocol called NC-MAC, which has been proposed by us in order to significantly enhance system performance. This protocol introduces an approach that can accommodate both cooperative communication and network coding for wireless ad hoc networks by slightly increasing overhead and modifying standards. The protocol's performance is evaluated using mathematical analysis and computer simulation and two performance measures, system throughput and average channel access delay, are used for a performance comparison with previous schemes. It is assumed that all the frames exchanged over a wireless channel are susceptible to transmission errors, which is a new but more reasonable assumption differentiating this research from previous research. Numerical results show this protocol provides significantly enhanced system performance compared with conventional cooperative MAC protocols used in previous research. For instance, system performance is 47% higher using the NC-MAC protocol than when using the rDCF protocol.

• 전기학회논문지
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• 제58권6호
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• pp.1238-1240
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• 2009

In the wireless sensor network, cooperative transmission is an effective technique to combat multi-path fading and reduce transmitted power. Relay selection and power allocation are important technical issues to determine the performance of cooperative transmission. In this paper, we proposed a new multi-relay selection and power allocation algorithm to increase network lifetime. The proposed relay selection scheme minimizes the transmitted power and increase the network lifetime by considering residual power as well as channel conditions. Simulation results show that proposed algorithm obtains much longer network lifetime than the conventional algorithm.

• 한국통신학회논문지
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• 제36권3C호
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• pp.170-174
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• 2011

본 논문은 양방향 중계 채널(Two-Way Relay Channel) 에서 기존에 연구되었던 협력 통신(Cooperative Communication) 에서 네트워크 부호화(Network Coding)에 대해 간단히 소개한다. 협력 통신 시스템에서의 직교성을 이용한 새로운 네트워크 부호화 기법을 제안한다. 제안된 직교 사상 네트워크 부호화 기법은 기존에 널리 사용되고 있는 DF(Decode-and-Forward) 모듈러 합 기법의 전송률을 유지하면서 DF 기법의 단점인 오류 전파(Error Propagation) 현상을 제거하여 향상된 BER(Bit Error Rate) 성능을 보인다.

• 한국통신학회논문지
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• 제36권2A호
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• pp.133-138
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• 2011

This paper presents an information theoretic outage analysis for physical layer of a cooperative multihop wireless network. Our analysis shows that cooperation by selecting a proper relay at each hop increases the coverage or data rate of the network. In our analysis we consider both symmetric and asymmetric network model. We also investigate the availability of cooperative relay at each hop and show that end-to-end performance of the network depends on the relay selection procedure at each hop. We also verify our analytical results with simulations.