위성 네트워크에서 처리량 향상을 위한 충돌 인식 랜덤 액세스 기법
Collision Aware Random Access Schemes for Throughput Enhancement in Satellite Networks
- 주제(키워드) "위성 네트워크 , " "랜덤 액세스"
- 발행기관 아주대학교
- 지도교수 임재성
- 발행년도 2015
- 학위수여년월 2015. 2
- 학위명 박사
- 학과 및 전공 일반대학원 컴퓨터공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000018839
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Satellite networks (SATNETs) have become important for next-generation communication infrastructures because of their advantages, such as wide service areas, centralized management, and ease of installation at any geographic location. Next-generation SATNETs require an efficient multiple access scheme that is able to handle a large number of satellite terminals and bursty traffic conditions. Random access (RA) schemes are suitable for these conditions. For transmitting user traffic through an RA channel, the enhancement of the throughput is the most important aspect. For this reason, many enhanced RA schemes that use successive interference cancellation (SIC) have been developed. However, when the traffic load exceeds a certain amount, the throughput decreases sharply because of the increasing number of collisions that cannot be resolved by SIC. Thus, for a further improvement in the throughput, the development of new RA schemes to reduce collision probability and overcome collision effects is required. This dissertation addresses traffic load control (TLC) schemes for the stabilization of a traffic-load-sensitive RA channel and presents the design of new RA schemes based on advanced coding techniques. We propose two TLC schemes: 1) access control contention resolution diversity slotted ALOHA (AC-CRDSA), and 2) fast congestion control (FCC). These schemes provide an environment in which the SIC for RA schemes can fully operate. We also propose two RA schemes based on advanced coding techniques: 3) analog network coding ALOHA (ANC-ALOHA), and 4) augmented cyclic code shift keying spread spectrum ALOHA (ACCSK/SSA). These schemes facilitate the alleviation of collision effects and maximization of SIC utilization in the slotted and asynchronous RA system. For enhanced RA schemes using SIC and packet repetition, AC-CRDSA provides an accurate traffic load estimation technique. AC-CRDSA controls the traffic load on a channel according to the estimated traffic load and maintains the maximum throughput under a high traffic load. The inflow of excessive traffic larger than the maximum throughput causes congestion in an RA channel. The operation of FCC is based on the backlogged traffic load that has suffered transmission failures in previous frames, and ensures the transmission priority of backlogged traffic. Thus, FCC guarantees both maximum throughput and a low packet loss ratio under severe time-varying traffic conditions. In a slotted RA channel, ANC-ALOHA provides a connection establishment between two users who want to use analog network coding (ANC), and guarantees successful transmission from start to finish. It also provides a channel estimation technique for slotted channels, which is a prerequisite of SIC. By exploiting the inherent advantages of ANC, ANC-ALOHA almost doubles the throughput of slotted RA schemes. In an asynchronous RA channel, ACCSK/SSA significantly improves spectral efficiency and simplifies the correlator configuration. Combined with SIC, ACCSK/SSA achieves additional throughput enhancement, even in the presence of unbalanced packet power.
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Contents
Abstract
Contents
List of Figures
List of Tables
List of Acronyms
1 Introduction
1.1 Background
1.2 Contributions
1.3 Outline of Thesis
2 Overview of Satellite Networks and Random Access Schemes
2.1 Overview of Satellite Networks using MF-TDMA
2.2 Random Access Schemes using SIC
2.3 Random Access Schemes with Reservation
3 Traffic Load Control for Enhanced Random Access Schemes
3.1 Load Control Problems in Random Access Schemes using SIC
3.2 Traffic Load Estimation for CRDSA
3.2.1 Traffic Load Estimation Scheme for CRDSA
3.2.2 Performance Evaluation
3.3 AC-CRDSA: Access Control CRDSA
3.3.1 System Model
3.3.2 Protocol Details
3.3.3 Performance Evaluation
3.4 FCC: Fast Congestion Control
3.4.1 Related Works
3.4.2 System Model
3.4.3 Protocol Details
3.4.4 Performance Evaluation
3.5 Chapter Summary
4 Enhanced Random Access Schemes based on Advanced Coding Technique
4.1 Collision Problems of Slotted and Asynchronous Random Access
4.2 ANC-ALOHA: Analog Network Coding ALOHA
4.2.1 Related Work and Problem Description
4.2.2 Protocol Details
4.2.3 Throughput Analysis using CTA
4.2.4 Performance Analysis using TUA
4.3 ACCSK/SSA: Augmented Cyclic Code Shift Keying Spread Spectrum ALOHA
4.3.1 Related Works and Problem Description
4.3.2 Code Design of ACCSK and ACCSK/SSA
4.3.3 Performance Evaluation
4.4 Chapter Summary
5 Conclusions
References
