• Title/Summary/Keyword: power and rate allocation

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A Study on MIMO-ARQ Scheme Using D-MSSTC (D-MSSTC를 이용한 MIMO-ARQ에 관한 연구)

  • Jeon, Chanyong;Lee, Jeong Woo
    • Journal of IKEEE
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    • v.21 no.1
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    • pp.70-72
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    • 2017
  • We proposed a multi-input multi-output automatic repeat request (MIMO-ARQ) scheme using double multi-strata space-time code (D-MSSTC) for high spectral efficiency in $4{\times}N_r$ MIMO systems. To improve error performance of the proposed scheme, we allocate power and phase to each layer of MSSTC over every transmission. Additionally, we suboptimally optimize power allocation to maximize the minimum coding gain distance of D-MSSTC and phase allocation to efficiently minimize inter-layer interference in MSSTC. In simulation results, it is observed that the proposed MIMO-ARQ scheme based on D-MSSTC shows better block error rate (BLER) performance than conventional schemes.

Near-BER lossless Asymmetric 2PAM non-SIC NOMA with Low-Complexity and Low-Latency under User-Fairness

  • Chung, Kyuhyuk
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.2
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    • pp.43-51
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    • 2021
  • As the number of mobile devices has been increasing tremendously, system capacity should be enlarged in future next generation communication, such as the fifth-generation (5G) and beyond 5G (B5G) mobile networks. For such future networks, non-orthogonal multiple access (NOMA) has been considered as promising multiple access technology. In this paper, to reduce both latency and complexity in existing NOMA, we propose non-successive interference cancellation (SIC) NOMA with asymmetric binary pulse amplitude modulation (2PAM), nearly without bit-error rate (BER) loss. First, we derive the closed form of BER expressions for non-SIC NOMA with asymmetric 2PAM, especially under Rayleigh fading channels. Then, it is shown that the BER performance of the stronger channel user who is supposed to perform SIC in conventional NOMA can be nearly achieved by the proposed non-SIC NOMA with asymmetric 2PAM, especially without SIC. Furthermore, we also show that the BER performance of the weaker channel user in conventional NOMA can be more closely achieved by the proposed non-SIC NOMA with asymmetric 2PAM. These BERs are shown to be achieved over the part of the power allocation range, which is consistent with the NOMA principle of user fairness. As a result, the non-SIC NOMA scheme with asymmetric 2PAM could be considered as a promising NOMA scheme toward next generation communication.

New Direction of Pilot Rural Development -With Respect to Rural Settlement Zone Development Project- (새로운 시범(示範) 농촌(農村) 건설(建設) 방향(方向) - 농어촌정주생활권개발사업(農漁村定住生活圈開發事業)을 중심으로 -)

  • Lim, Jae Hwan
    • Korean Journal of Agricultural Science
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    • v.22 no.2
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    • pp.209-222
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    • 1995
  • To mitigate the development gap between urban and rural area, the government has implemented project planning as the Rural Integrated Development in each Gun level since 1986. On account of shortage of the development fund, the government had changed the Gun level development into Myeon level development so called the Rural Central Settlement Zone Development. The government had started nine pilot projects throughout Korea from 1990. This study is aimed at identifing problems that found in the course of implementation of the projects and recommending the new direction of the successful implementation of the projects in the future. The problems and directions found in the cource of project implementation were as follows: 1. Project implementation by investment priority considering economic and financial rate of return should be made. 2. Objective project planning should be made. 3. Equal allocation of the limited investment fund by group interest and egoism should be prohibited. 4. Enforcement of special man power should be taken into account. 5. Unification of the diversified existing terms and conditions of loans for house construction and improvement. 6. Road development oriented budget allocation should be improved. 7. Sufficient development fund should be procured considering the present rate of sufficiency of the project cost as 36%. 8. Sufficient supply of the credit loans for improvement of living environment of the farmers should be realized. 9. Rational implementation planning in connection with farm household income source development should be made.

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Margin Adaptive Optimization in Multi-User MISO-OFDM Systems under Rate Constraint

  • Wei, Chuanming;Qiu, Ling;Zhu, Jinkang
    • Journal of Communications and Networks
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    • v.9 no.2
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    • pp.112-117
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    • 2007
  • In this paper, we focus on the total transmission power minimization problem for downlink beamforming multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems while ensuring each user's QoS requirement. Although the linear integer programming (LIP) solution we formulate provides the performance upper bound of the margin adaptive (MA) optimization problem, it is hard to be implemented in practice due to its high computational complexity. By regarding each user's equivalent channel gain as approximate independent values and using iterative descent method, we present a heuristic MA resource allocation algorithm. Simulation results show that the proposed algorithm efficiently converges to the local optimum, which is very close to the performance of the optimal LIP solution. Compared with existing space division multiple access (SDMA) OFDM systems with or without adaptive resource allocation, the proposed algorithm achieves significant performance improvement by exploiting the frequency diversity and multi-user diversity in downlink multiple-input single-output (MISO) OFDM systems.

Energy Optimal Transmission Strategy in CDMA System: Duality Perspective

  • Oh, Changyoon
    • Journal of the Korea Society of Computer and Information
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    • v.20 no.9
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    • pp.61-66
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    • 2015
  • We investigate rate scheduling and power allocation problem for a delay constrained CDMA systems. Specifically, we determine an energy efficient scheduling policy, while each user maintains the short term (n time slots) average throughput. More importantly, it is shown that the optimal transmission strategy for the uplink is same as that of the downlink, called uplink and downlink duality. We then examine the performance of the optimum transmission strategy for the uplink and the downlink for various system environments.

Geometric Programming Applied to Multipoint-to-Multipoint MIMO Relay Networks

  • Kim, Jaesin;Kim, Suil;Pak, Ui-Young
    • Journal of Communications and Networks
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    • v.17 no.3
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    • pp.241-246
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    • 2015
  • In this paper, we consider a relaying system which employs a single relay in a wireless network with distributed sources and destinations. Here, all source, destination, and relay nodes are equipped with multiple antennas. For amplify-and-forward relay systems, we confirm the achievable sum rate through a joint multiple source precoders and a single relay filter design. To this end, we propose a new linear processing scheme in terms of maximizing the sum rate performance by applying a blockwise relaying method combined with geometric programming techniques. By allowing the global channel knowledge at the source nodes, we show that this joint design problem is formulated as a standard geometric program, which can guarantees a global optimal value under the modified sum rate criterion. Simulation results show that the proposed blockwise relaying scheme with the joint power allocation method provides substantial sum rate gain compared to the conventional schemes.

Capacity of Spectrum Sharing Cognitive Radio with MRC Diversity under Delay Quality-of-Service Constraints in Nakagami Fading Environments

  • Zhang, Ping;Xu, Ding;Feng, Zhiyong
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.4
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    • pp.632-650
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    • 2013
  • The paper considers a spectrum sharing cognitive radio (CR) network coexisting with a primary network under the average interference power constraint. In particular, the secondary user (SU) is assumed to carry delay-sensitive services and thus shall satisfy a given delay quality-of-service (QoS) constraint. The secondary receiver is also assumed to be equipped with multiple antennas to perform maximal ratio combining (MRC) to enhance SU performance. We investigate the effective capacity of the SU with MRC diversity under aforementioned constraints in Nakagami fading environments. Particularly, we derive the optimal power allocation to achieve the maximum effective capacity of the SU, and further derive the effective capacity in closed-form. In addition, we further obtain the closed-form expressions for the effective capacities under three widely used power and rate adaptive transmission schemes, namely, optimal simultaneous power and rate adaptation (opra), truncated channel inversion with fixed rate (tifr) and channel inversion with fixed rate without truncation (cifr). Numerical results supported by simulations are presented to consolidate our studies. The impacts on the effective capacity of various system parameters such as the number of antennas, the average interference power constraint and the delay QoS constraint are investigated in detail. It is shown that MRC diversity can significantly improve the effective capacity of the SU especially for cifr transmission scheme.

Achievable Rate Analysis for Opportunistic Non-orthogonal Multiple Access-Based Cooperative Relaying Systems

  • Lee, In-Ho;Lee, Howon
    • Journal of Information Processing Systems
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    • v.13 no.3
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    • pp.630-642
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    • 2017
  • In this paper, we propose the opportunistic non-orthogonal multiple access (NOMA)-based cooperative relaying system (CRS) with channel state information (CSI) available at the source, where CSI for the source-to-destination and source-to-relay links is used for opportunistic transmission. Using the CSI, for opportunistic transmission, the source instantaneously chooses between the direct transmission and the cooperative NOMA transmission. We provide an asymptotic expression for the average achievable rate of the opportunistic NOMA-based CRS under Rayleigh fading channels. We verify the asymptotic analysis through Monte Carlo simulations, and compare the average achievable rates of the opportunistic NOMA-based CRS and the conventional one for various channel powers and power allocation coefficients used for NOMA.

Avoided Generation Costs of IPPS Considering Forced Outage Rate and Economic Loading Order (고장정지율과 경제적 투입순서를 고려한 민자발전소의 회피발전비용 계산)

  • 원종률;박종배;김진호
    • Journal of Energy Engineering
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    • v.11 no.1
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    • pp.47-58
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    • 2002
  • This paper presents a new method for the evaluation of avoided generation costs. Unlike conventional load decrement method, it exactly considers forced outage rate and economic loading order of IPPs (Independent Power Producers). Therefore we can provide exact generation avoided costs of IPPs by the developed method. Because probabilistic simulation is conducted in this method, effects on the costs of IPPs are exactly considered. Also we suggest an allocation method of avoided generation costs by participation factor. In the case studies we have shown avoided generation costs considering loading order and forced out-age rate by using this method.

Efficient Interference Control Technology for Vehicular Moving Networks

  • Oh, Sung-Min;Lee, Changhee;Lee, Jeong-Hwan;Park, Ae-Soon;Shin, Jae Sheung
    • ETRI Journal
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    • v.37 no.5
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    • pp.867-876
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    • 2015
  • This paper proposes an efficient interference control scheme for vehicular moving networks. The features of the proposed scheme are as follows: radio resources are separated into two resource groups to avoid interference between the cellular and vehicle-to-vehicle (V2V) links; V2V links are able to share the same radio resources for an improvement in the resource efficiency; and vehicles can adaptively adjust their transmission power according to the interference among the V2V links (based on the distributed power control (DPC) scheme derived using the network utility maximization method). The DPC scheme, which is the main feature of the proposed scheme, can improve both the reliability and data rate of a V2V link. Simulation results show that the DPC scheme improves the average signal-to-interference-plus-noise ratio of V2V links by more than 4 dB, and the sum data rate of the V2V links by 15% and 137% compared with conventional schemes.