• Title/Summary/Keyword: transmit power control

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Transmit Power and MMSE Receiver Filter Algorithm for Multi Access Points (다중 엑세스 포인트에서 전송전력과 MMSE 수신필터 알고리즘)

  • Oh, Changyoon
    • IEMEK Journal of Embedded Systems and Applications
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    • v.15 no.3
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    • pp.111-118
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    • 2020
  • We investigate the optimization problem of transmit power control and MMSE Receiver filter for multi access points environment. Previous work showed that increasing the number of access points decreases the transmit power consumption. Accordingly, transmit power control algorithm was developed in such a way that the transmit power is minimized, while each terminal meets Signal to Interference and Noise Ratio Requirement. In this work, we further reduce the transmit power consumption by optimizing the transmit power level and the MMSE receiver filter together. We showed that the proposed joint optimization algorithm satisfies the necessary and sufficient conditions to be standard interference function, which guarantees convergence and minimum transmit power consumption. We observed that the proposed algorithm outperforms the algorithm which only optimizes the transmit power.

D2D Power Control in the Cellular System: Non Cooperative Game Theoretic Approach

  • Oh, Changyoon
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.3
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    • pp.25-31
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    • 2018
  • In this paper, we consider the game theoretic approach to investigate the transmit power optimization problem where D2D users share the uplink of the cellular system. Especially, we formulate the transmit power optimization problem as a non cooperative power control game. In the user wide sense, each user may try to select its transmit power level so as to maximize its utility in a selfish way. In the system wide, the transmit power levels of all users eventually converge to the unique point, called Nash Equilibrium. We first formulate the transmit power optimization problem as a non cooperative power control game. Next, we examine the existence of Nash Equilibrium. Finally, we present the numerical example that shows the convergence to the unique transmit power level.

Transmit Power Control for Multi-Access Points Environment (다수 개의 엑세스 포인트 환경에서 전송전력 제어)

  • Oh, Changyoon
    • Journal of Korea Society of Industrial Information Systems
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    • v.25 no.2
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    • pp.49-56
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    • 2020
  • We investigate the transmit power control algorithm for multi-access points environment. Each terminal may transmit a signal to one of these access points. Each access point may receive a signal from desired terminals as well as interference from neighbor terminals. In this paper, a transmit power control algorithm is developed such that the total transmit power is minimized, while each terminal meets the target signal to interference ratio (SIR) requirement. In particular, the effect of increasing the number of access-points on the total transmit power consumption is analyzed. Based on this analysis, we propose a convergence guaranteed power control algorithm. We prove that the proposed iterative algorithm always converges to the target SIR. In addition, we show that the proposed algorithm optimizes the transmit power level. Simulation results show that the proposed algorithm guarantees convergence regardless of the number of access points. We also observed that increasing the number of access points reduces the total transmit power consumption.

Performance Verification of Deep Learning based Transmit Power Control (딥러닝 기반 송신전력 조절방안의 성능검증)

  • Lee, Woongsup;Kim, Seong Hwan;Ryu, Jongyeol;Ban, Tae-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.3
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    • pp.326-332
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    • 2019
  • Recently, the deep learning technology has gained lots of attention which leads to its application to various fields. Especially, there are recent attempts to overcome the limit of wireless communications systems through the use of the deep learning. In this paper, we have verified the performance of deep learning based transmit power control scheme. Unlike previous transmit power control schemes where the optimal transmit power is derived by solving the optimization problem explicitly, in the deep learning based transmit power control, the general solver for the optimization problem is derived through the deep neural network (DNN). Especially, by using the spectral efficiency as the loss function of DNN, the training can be performed without needing labels. Through simulation based on Tensorflow, we confirm that the transmit power control based on deep learning can achieve the optimal performance while reducing the computational complexity by 1/200.

D2D Power Control in the Cellular System: Iterative Algorithm and Convergence

  • Oh, Changyoon
    • Journal of the Korea Society of Computer and Information
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    • v.22 no.9
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    • pp.41-47
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    • 2017
  • In this paper, we consider the case where D2D users and the cellular user share the uplink of the cellular system. We propose an iterative power control algorithm that converges to the optimum power value. Each user iteratively updates its transmit power level according to the interference function. Finally, all D2D users and cellular user that participate in the transmission get the optimum transmit power level. We first investigate the interference structure and define the interference function. Then, we show that the considered interference function belongs to the standard interference function that converges the unique transmit power level. Through numerical examples, the convergence of the proposed power control algorithm is examined in the various transmission scenarios.

Transmission Power-Based Spectrum Sensing for Cognitive Ad Hoc Networks

  • Choi, Hyun-Ho
    • Journal of information and communication convergence engineering
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    • v.12 no.2
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    • pp.97-103
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    • 2014
  • In spectrum sensing, there is a tradeoff between the probability of missed detection and the probability of a false alarm according to the value of the sensing threshold. Therefore, it is important to determine the sensing threshold suitable to the environment of cognitive radio networks. In this study, we consider a cognitive radio-based ad hoc network where secondary users directly communicate by using the same frequency band as the primary system and control their transmit power on the basis of the distance between them. First, we investigate a condition in which the primary and the secondary users can share the same frequency band without harmful interference from each other, and then, propose an algorithm that controls the sensing threshold dynamically on the basis of the transmit power of the secondary user. The analysis and simulation results show that the proposed sensing threshold control algorithm has low probabilities of both missed detection and a false alarm and thus, enables optimized spectrum sharing between the primary and the secondary systems.

Study on the Transmit Power, MMSE Receiver Filter, and Access Point Selection Optimization Algorithm

  • Oh, Changyoon
    • Journal of the Korea Society of Computer and Information
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    • v.26 no.9
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    • pp.65-72
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    • 2021
  • We consider the joint optimization problem of transmit power level, MMSE receiver filter and access point(AP) selection for multi access points environment. In the previous work, transmit power and MMSE receiver filter were jointly optimized[1] and transmit power and best access point were optimized jointly[2]. For each case, the algorithm was proposed and its convergence which guarantees the minimum total transmit power was proved. In this paper, we further improve the algorithm by jointly optimizing three parameters. More specifically, 1) we propose the algorithm by considering transmit power, MMSE receiver filter and access point selection jointly. 2) we prove that the proposed algorithm guarantees convergence with minimum transmit power consumption. In the simulation results, it is shown that proposed algorithm outperforms two other algorithms, i.e., 1) algorithm with transmit power and MMSE receiver filter, and 2) algorithm with transmit power and best access point selection.

Distributed Transmit Power Control for Optimal End-to-End Throughput in Wireless Multihop Networks (무선 멀티홉 네트워크에서 종단간 최적 전송률을 위한 분산 송신전력제어)

  • Choi, Hyun-Ho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.11 no.2
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    • pp.92-101
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    • 2012
  • In this paper, we propose a distributed transmit power control algorithm for optimal end-to-end throughput in wireless multihop networks. Considering a solidarity property of link rates consisting of a multihop link and the fact that the multihop end-to-end throughput is determined by the minimum link rate, the proposed scheme controls the transmit power to make all link rates be equal and so maximizes the end-to-end throughput of multihop link. In addition, in the proposed scheme the transmit node calculates its transmit power autonomously in a distributed manner just through the information sharing with its neighbor nodes and so decreases the information sharing overhead. Simulation results show that the proposed scheme achieves significant improvements in terms of end-to-end throughput and power consumption compared with the conventional maximum equal power allocation scheme.

Cooperative Power Control Scheme for a Spectrum Sharing System

  • Ban, Tae-Won;Jung, Bang-Chul
    • Journal of information and communication convergence engineering
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    • v.9 no.6
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    • pp.641-646
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    • 2011
  • In this paper, we investigate a power control problem which is very critical in underlay-based spectrum sharing systems. Although an underlay-based spectrum sharing system is more efficient compared to an overlay-based spectrum sharing system in terms of spectral utilization, some practical problems obstruct its commercialization. One of them is a real-time-based power adaptation of secondary transmitters. In the underlay-based spectrum sharing system, it is essential to adapt secondary user's transmit power to interference channel states to secure primary users' communication. Thus, we propose a practical power control scheme for secondary transmitters. The feedback overhead of our proposed scheme is insignificant because it requires one-bit signaling, while the optimal power control scheme requires the perfect information of channel states. In addition, the proposed scheme is robust to feedback delay. We compare the performance of the optimal and proposed schemes in terms of primary user's outage probability and secondary user's throughput. Our simulation results show that the proposed scheme is almost optimal in terms of both primary user's outage probability and secondary user's throughput when the secondary user's transmit power is low. As the secondary user's transmit power increases, the primary user's outage probability of the proposed scheme is degraded compared with the optimal scheme while the secondary user's throughput still approaches that of the optimal scheme. If the feedback delay is considered, however, the proposed scheme approaches the optimal scheme in terms of both the primary user's outage probability and secondary user's throughput regardless of the secondary user's transmit power.

Multi-Access Points Transmit Power Control Algorithm in Consideration of the Channel Estimation Error and the Multi Rate Service (채널추정 에러와 다중 전송률 서비스를 고려한 다수 개의 엑세스포인트 전송전력제어 알고리즘)

  • Oh, Changyoon
    • Journal of Korea Society of Industrial Information Systems
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    • v.25 no.4
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    • pp.39-47
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    • 2020
  • We propose a multi-access points transmit power control algorithm in consideration of the channel estimation error and the multi-rate service. In the real communication systems, the channel estimation at the receiver side is imperfect due to limited number of pilot symbol usage. Furthermore, the multi-rate service is supported. We theoretically prove the uniqueness and the convergence of the proposed algorithm in multi-rate service environment. The proposed algorithm composes of one inner loop part and one outer loop part. Simulation results show that 1) the inner loop algorithm guarantees convergence of the transmit power level and the multi-rate service, 2) the outer loop algorithm compensates for the channel estimation error.