• Title/Summary/Keyword: selection transmission

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Prediction-Based Adaptive Selection Cooperation Schemes (예측 정보를 이용한 적응적 협력 선택기법)

  • Wang, Yu;Lee, Dong-Woo;Lee, Jae-Hong
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.11
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    • pp.18-24
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    • 2009
  • This paper proposes two novel prediction-based adaptive selection cooperation schemes combined with a new relay selection strategy. In the proposed schemes, the destination predicts whether the transmission will be successful or not before a single relay is selected to transmit source's decoded data. Depending on the prediction, the destination feeds back a command to the whole network. Numerical results show that the proposed schemes combined with the relay selection strategy successfully reduce its outage probability, improve its throughput, save transmitted power, and prolong the lifetime of the network.

Energy Harvesting in Multi-relay Multiuser Networks based on Two-step Selection Scheme

  • Guo, Weidong;Tian, Houyuan;Wang, Qing
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.9
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    • pp.4180-4196
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    • 2017
  • In this paper, we analyze average capacity of an amplify-and-forward (AF) cooperative communication system model in multi-relay multiuser networks. In contrast to conventional cooperative networks, relays in the considered network have no embedded energy supply. They need to rely on the energy harvested from the signals broadcasted by the source for their cooperative information transmission. Based on this structure, a two-step selection scheme is proposed considering both channel state information (CSI) and battery status of relays. Assuming each relay has infinite or finite energy storage for accumulating the energy, we use the infinite or finite Markov chain to capture the evolution of relay batteries and certain simplified assumptions to reduce computational complexity of the Markov chain analysis. The approximate closed-form expressions for the average capacity of the proposed scheme are derived. All theoretical results are validated by numerical simulations. The impacts of the system parameters, such as relay or user number, energy harvesting threshold and battery size, on the capacity performance are extensively investigated. Results show that although the performance of our scheme is inferior to the optimal joint selection scheme, it is still a practical scheme because its complexity is much lower than that of the optimal scheme.

Performance Analysis of Coded Cooperation Protocol with Reactive and Proactive Relay Selection

  • Asaduzzaman, Asaduzzaman;Kong, Hyung-Yun
    • Journal of electromagnetic engineering and science
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    • v.11 no.2
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    • pp.133-142
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    • 2011
  • Coded cooperation that integrates channel coding in cooperative transmission has gained a great deal of interest in wireless relay networks. The performance analysis of coded cooperation protocol with multiple relays is investigated in this paper. We show that the diversity order achieved by the coded cooperation in a multi-relay wireless network is not only dependent on the number of cooperating relays but is also dependent on the code-rate of the system. We derive the code-rate bound, which is required to achieve the full diversity gain of the order of cooperating nodes. The code-rate required to achieve full diversity is a linearly decreasing function of the number of available relays in the network. We show that the instantaneous channel state information (CSI)-based relay selection can effectively alleviate this code-rate bound. Analysis shows that the coded cooperation with instantaneous CSI-based relay selection can achieve the full diversity, for an arbitrary number of relays, with a fixed code-rate. Finally, we develop tight upper bounds for the bit error rate (BER) and frame error rate (FER) of the relay selection based on coded cooperation under a Rayleigh fading environment. The analytical upper bounds are verified with simulation results.

Adaptation for Object-based MPEG-4 Content with Multiple Streams (다중 스트림을 이용한 객체기반 MPEG-4 컨텐트의 적응 기법)

  • Cha Kyung-Ae
    • Journal of Korea Society of Industrial Information Systems
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    • v.11 no.3
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    • pp.69-81
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    • 2006
  • In this paper, an adaptive algorithm is proposed in streaming MPEG-4 contents with fluctuating resource amount such as throughput of network conditions. In the area of adaptive streaming issue, a lot of researches have been made on how to represent encoded media(such as video) bitstream in scalable way. By contrast, MPEG-4 supports object-based multimedia content which is composed of various types of media streams such as audio, video, image and other graphical elements. Thus, it can be more effective to provide individual media streams in scalable way for streaming object-based content to heterogeneous environment. The proposed method provides the multiple media streams corresponding to an object with different qualities and bit rate in order to support object based scalability to the MPEG-4 content. In addition, an optimal selection of the multiple streams for each object to meet a given constraint is proposed. The selection process is adopted a multiple choice knapsack problem with multi-step selection for the MPEG-4 objects with different scalability levels. The proposed algorithm enforces the optimal selection process to maintain the perceptual qualities of more important objects at the best effort. The experimental results show that the set of selected media stream for presenting objects meets a current transmission condition with more high perceptual quality.

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Cooperative Relaying Scheme Using Multiple Relays in Two-Way Relay Network (양방향 중계 네트워크에서 다중 중계기를 이용한 협력 중계 기법)

  • Park, Ji-Hwan;Kong, Hyung-Yun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.7
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    • pp.815-822
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    • 2010
  • Two-way relaying scheme based on relay selection can not only achieve higher rate but also get the selection diversity gain according to the number of relays. However the scheme can not achieve combining gain because it does not consider the direct link between users. In this paper, we propose, with multiple relays, opportunistic cooperative two-way relaying scheme and incremental cooperative two-way relaying scheme which can achieve both selection diversity gain and combining gain. Simulation results show that proposed scheme outperform the conventional scheme by achieving both combining gain and selection diversity gain according to the number of relays.

Transmit Antenna Selection for Spatial Multiplexing with Per Antenna Rate Control and Successive Interference Cancellation (순차적인 간섭제거를 사용하는 공간 다중화 전송 MIMO 시스템의 전송 안테나 선택 방법에 관한 연구)

  • Mun Cheol;Jung Chang-Kyoo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.6C
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    • pp.560-569
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    • 2005
  • This paper proposes an algorithm for transmit antenna selection in a multi-input multi-output(MIMO) spatial multiplexing system with per antenna rate control(PARC) and an ordered successive interference cancellation (OSIC) receiver. The active antenna subset is determined at the receiver and conveyed to the transmitter using feedback information on transmission rate per antenna. We propose a serial decision procedure consisting of a successive process that tests whether antenna selection gain exists when the antenna with the lowest pre-processing signal to interference and noise ratio(SINR) is discarded at each stage. Furthermore, we show that 'reverse detection ordering', whereby the signal with the lowest SINR is decoded at each stage of successive decoding, widens the disparities among fractions of the whole capacity allocated to each individual antenna and thus maximizes a gain of antenna selection. Numerical results show that the proposed reverse detection ordering based serial antenna selection approaches the closed-loop MIMO capacity and that it induces a negligible capacity loss compared with the heuristic selection strategy even with considerably reduced complexity.

A Base Station Clustering Method Based on Sequential Selection Approach (순차적 선택 기반의 전송 기지국 클러스터 형성 방법)

  • Yoo, Hyung-Gil;Sung, Won-Jin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.9
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    • pp.1-9
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    • 2011
  • In this paper, we propose an efficient method to create clusters of geographically distributed base stations which cooperatively transmit signals in cellular mobile communication systems. The proposed method utilizes a sequential selection approach to choose candidate base stations which can provide maximum weighted sum-rate gain when they participate in the cooperative transmission with the existing cluster. In particular, the proposed method limits the maximum number of base stations in a cluster by considering the system operational and implementation complexities. Moreover, the combinations of clusters dynamically change along with variations of channel environments. Through computer simulations, performance of the proposed method is verified by comparing with the non-cooperative transmission method and the static clustering method. Numerical result shows that the proposed sequential selection based clustering method is especially advantageous for the performance improvement of lower percentile users in terms of average throughput, and thus the proposed method can effectively improve the fairness among users.

Cell Selection Method using Multi-Criteria Decision Making in Heterogeneous Networks (이종 망에서 퍼지 다기준 의사 결정을 이용한 셀 선정 방법)

  • Lee, Jong-Chan;Park, Sang-Joon
    • Journal of the Korea Society for Simulation
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    • v.17 no.3
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    • pp.1-8
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    • 2008
  • It is essential to maintain constant QoS despite of cell overload or erroneous wireless link during transmission because QoS of a multimedia service may be severely degraded by small delay or packet loss. This paper deals with a cell selection method for supporting the QoS of multimedia services over heterogeneous networks. The proposed scheme is based on Fuzzy Multi-Criteria Decision Making (FMCDM), in which uncertain parameters such as user system preference, the communication cost and cell load, and the transmission delay are used in the decision process using the aggregation function in fuzzy set theory. In this scheme, errors in the evaluation parameters impose milder changes on the total evaluation value than in binary logics. Simulation is focused on the average delay and packet loss rate, and the simulation results show that our proposed method provides mobile terminals the optimal performance.

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Partial Retransmission Turbo HARQ Using the Sign Transitions of A Posteriori Values (사후 정보 값의 부호 변화를 이용한 부분 재전송 방식의 터보 HARQ)

  • Jang, Yeon-Soo;Yoon, Dong-Weon;Hyun, Kwang-Min;Lee, Sang-Hyun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.8
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    • pp.768-775
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    • 2011
  • Since error compensation schemes guaranteeing high reliability are required in wireless communication systems for the transmission of the large amount of data, as an efficient error compensation scheme the turbo HARQ scheme combining automatic repeat request and turbo coding has been studied in many places in the literature. In the case of conventional turbo HARQ schemes, the transmitter recognizing NAK signals repetitively sends the whole unit packet to the receiver although the received packet can be partially correctable. Through two successive processes, selection of uncorrectable error data and retransmission of only the relevant parts of the information data, transmission efficiency can be improved. In this paper, we present an error data selection criterion for retransmission using the sign transitions of A Posteriori values and propose a tubo HARQ scheme based on the partial retransmission technique. Through a computer simulation, we show and analyze the performance of the proposed scheme with transmission efficiency.

A Study on QAM Transmission Schemes for Constant Amplitude Coded Multicode Biorthogonal Modulation (정진폭 부호화된 다중부호 이진직교 변조의 QAM 전송방식에 대한 연구)

  • Hong, Dae-Ki;Kim, Sun-Hee;Kim, Young-Sung;Lim, Seung-Ok;Cho, Jin-Woong;Kang, Sung-Jin
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.2
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    • pp.343-351
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    • 2008
  • In this paper, we investigate the design of the QAM(Quadrature Amplitude Modulation) method for the CACB(Constant Amplitude Coded Multicode Biorthogonal) scheme. The modulation method fan improve the transmission data rate by increasing the BE(Bandwidth Efficiency). Additionally, we can improve the system performance by using the QAM SD(Soft Decision) method with the MDSA(Minimum Distance Selection Algorithm). Finally, the DFE(Decision Feedback Equalizer) for the CACB-QAM is simulated under the MPF(MultiPath Fading) channel for real implementation. The proposed scheme can be used for the PHY(PHYsical layer) standard of the WPAN(Wireless Personal Area Network) requiring high rate data transmission.