레일리 페이딩 채널에서 협력 다중점 합동 다이버시티 전송에 대한 연구
A Study on Coordinated Multi-point Joint Diversity Transmission in Rayleigh Fading Channels
- 발행기관 아주대학교
- 지도교수 오성근
- 발행년도 2014
- 학위수여년월 2014. 8
- 학위명 박사
- 학과 및 전공 일반대학원 전자공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000017906
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
In this dissertation, we study a coordinated multi-point (CoMP) joint diversity transmission network (JDTN) in Rayleigh fading channels. First, as a useful tool to analyze the performance of the CoMP JDTN, we derive a closed-form ergodic cooperative capacity (ECC) expression of the CoMP JDTN in Rayleigh fading channels. To obtain the closed-form ECC expression, we first derive a closed-form probability density function (PDF) of the instantaneous diversity-combined signal-to-noise ratio, and then a closed-form ECC expression for the CoMP JDTN by using the derived closed-form PDF. Second, using the closed-form ECC expression, we deal with the joint power allocation (JPA) problem for the CoMP JDTN with the constraint on the total coordination point power (TCPP), aimed at maximizing the ECC in Rayleigh fading channels. We first consider the coordinated two-point (Co2P) JDTN that consists of two coordinated transmission points (CTPs) - CTP1 and CTP2 - and a user equipment, under the unity TCPP. We obtain the relationship that yields the optimum CTP1 power with respect to the mean branch gain-to-noise ratios (GNRs). Then, we introduce two simple log-linear approximated (LLA) expressions for the optimum CTP1 power, with exact slope and approximated slope, respectively, at the balanced point. Using the LLA expressions, we also draw efficient criteria for turning off Co2P joint diversity transmission (JDT). Next, we extend the JPA problem to the case of a non-unity TCPP constraint. We furthermore introduce more accurate log-quadratic approximated (LQA) expressions for obtaining the CTP powers. Then, we extend our study to a coordinated three-point (Co3P) JDTN. Given the mean branch GNRs, we obtain a LLA expression for obtaining the optimum power of the third CTP (i.e., the worst quality-providing CTP). After obtaining the third-CTP power, we obtain the CTP powers of the two better quality-providing CTPs by invoking the LLA CTP power expressions for Co2P JDT power allocation, under the remaining power that is given by the TCPP minus the third-CTP power. Finally, we deal with the JPA problem for the CoMP JDTN with an ergodic rate requirement in Rayleigh fading channels, aimed at minimizing the TCPP. Prior to the JPA problem for minimizing the TCPP in the CoMP JDTN, we present several approximate expressions for the EC of a single-branch Rayleigh-faded channel and the ECC of cooperative-branch Rayleigh-faded channels. Next, for the Co2P JDTN, we derive an optimality-conserving condition for the optimum CTP powers. We present two simple expressions such as a LLA expression for optimum CTP1 power and a LQA expression for optimum CTP2 power. Then, we present an improved JPA method for the Co2P JDTN, which can maintain the TCPP at an almost optimum level for the ergodic rate requirement. In this improved method, we obtain a much better TCPP approximation to give the required ergodic rate by using the linear interpolation of two known nearby sets of TCPP versus the ergodic rate. Using the TCPP approximation, we then obtain two CTP powers by using the LQA and LLA CTP power expressions of Co2P JDT for ECC maximization under the TCPP constraint. We further extend this method to the Co3P JDTN according to the similar process to that in the Co2P JDTN.
more목차
List of Figures
Abbreviation
1 Introduction
1.1 Background and Motivation
1.2 Contributions
2 Closed-form Ergodic Cooperative Capacity for CoMP Joint Diversity Transmission
2.1 CoMP JDTN Model and Capacities
2.2 PDF of Instantaneous DC-SNR
2.3 Closed-form ECC
2.4 Proof of Theorem 2.1
2.5 ECC Behaviors
3 Joint Power Allocation for Ergodic Cooperative Capacity Maximization
3.1 CoMP JDTN Model
3.2 Problem Formulation and Optimum Power Allocation
3.3 JPA for Co2P JDT under Unity TCPP
3.4 JPA for Co2P JDT under Non-unity TCPP
3.5 JPA for Co3P JDT
3.6 Numerical Results
4 Approximations for Ergodic Capacities in Rayleigh fading Channels
4.1 Approximations for EC of a Single-branch Rayleigh-faded Channel
4.2 Approximation for ECC of Two-branch Rayleigh-faded Channels at the Balanced Point
4.3 Approximation for ECC of Three-branch Rayleigh-faded Channels at the Balanced Point
5 Joint Power Allocation for Total Coordination Point Power Minimization
5.1 Problem Formulation and Optimum Power Allocation
5.2 Approximated Expressions of JPA for Co2P JDT
5.3 JPA for Co2P JDT using Duality Condition
5.4 JPA for Co3P JDT using Duality Condition
5.5 Numerical Results
6 Conclusions
References
