Random Access Scheme with Reservation for Next Generation Satellite Networks
차세대 위성 네트워크를 위한 예약방식의 랜덤 접속 기법
- 주제(키워드) satellite network , random access , multiple access , NCW
- 발행기관 아주대학교
- 지도교수 임재성
- 발행년도 2013
- 학위수여년월 2013. 2
- 학위명 박사
- 학과 및 전공 일반대학원 NCW학과
- 실제URI http://www.dcollection.net/handler/ajou/000000013887
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
The topic of the high reliable and high efficient Random Access (RA) for Satellite Networks (SATNETs) is considered important for the Next-Generation SATNETs (NG-SATNETs), and numerous studies concerning this issue have been over 40 years. Now a days, the high performance RA scheme for SATNETs is necessary than ever before, since NG-SATNETs will be used to carry Internet traffic more and more among huge users. This will bring our global living life the new opportunities of the service models; e.g., for global coverage consumer transaction, Small Office Home Office (SOHO), and mobile messaging via SATNETs. Furthermore for emergency communication the SATNETs will be the most attractive infrastructure, since it does not need the fixed infrastructure. These features of SATNETs have been observed for the military transformation. Therefore many challenging issues are studied for the military communications. In general, RA schemes for SATNETs have been rarely used to transmit user traffic because of their low throughput of the traditional RA schemes (i.e., ALOHA, Slotted ALOHA, Diversity Slotted ALOHA) and the long propagation delay of SATNETs. Thus Demand Assigned (DA)-based multiple access schemes are used more for SATNETs. However, as the traffic property becomes more bursty (i.e., large ratio between the peak and average data rate), the DA-based multiple access schemes become less efficient. In this reason, high reliable/efficient RA schemes in SATNETs have been attracted interested for transmitting user traffic. The objective of this dissertation is to develop a novel RA scheme which has the property of the high reliability and the high efficiency for the NG-SATNETs. In this dissertation, the RA scheme with reservation for SATNETs, called by Reservation-Contention Resolution Diversity Slotted ALOHA (R-CRDSA), is proposed. The RCRDSA protocol can improve the channel throughput and the channel capacity efficiency more than CRDSA, in particular for the traffic of multi-packet messages which is considered as the traffic character in the NG-SATNETs. To investigate the performance of the R-CRDSA, analytic performances are derived by the observation of the transition between two successive frames, and the average number of packets in a message. The scheme performance is evaluated by developed analytic models in terms of the critical point, the throughput, and the capacity efficiency. The simulation results show that the analytic derivations are valid. In addition, the stability of the R-CRDSA is investigated. The stability analysis for an RA scheme is the most important measure for its practical use. In this dissertation, the stability model of the R-CRDSA is formulated. Using this formulation, various system configurations can be investigated under stable channel configurations to find optimal operational parameters in terms of average backlog time, traffic generation probability, and supportable user population. For example, minimum retransmission probability with minimum backlog time (delay), maximum traffic generation with maximum user population, and maximum user population with minimum delay, while guaranteeing the stability of channel. The method to exploit the Slot State Information (SSI) in SATNETs is also suggested in this dissertation. Inherently the SSI produced from the result of Interference Cancellation (IC) and the overhearing property of SATNETs. Therefore the exploiting the SSI can enhance the performance RA scheme in SATNETs for the load control mechanism and guaranteeing the traffic priority. The R-CRDSA is simple in its principle and is easy to implement with the same cost of the CRDSA, but it is suitable for users with multi-packet messages more. The R-CRDSA can be a good candidate for NG-SATNETs. In particular, for nextgeneration MILSATCOM, the R-CRDSA scheme will play an important role in applications via SATNETs such as Push-to-Talk (PTT), mobile messaging, Tactical Data Links (TDLs), sensor networks, and SCADA systems. Furthermore the stability analysis formulation of the R-CRDSA in this dissertation can be used to design NG-SATNETs and various service models planned for NG-MILSATCOM.
more목차
1 Introduction 1
1.1 Motivation 1
1.1.1 NG-SATNETs for NCW 1
1.1.2 Random Access Schemes for SATNETs 4
1.1.3 High Reliable/Efficient RA schemes for NG-SATNETs 5
1.2 Contributions 8
1.3 Organization 11
2 Background and Related Works 13
2.1 Overview of SATCOM 13
2.1.1 Characteristics of Satellite Communications 14
2.1.2 Advantages of Satellite Communications 16
2.1.3 Satellite Communications for Computer Networks 18
2.2 Multiple Access Schemes for SATNETs 20
2.2.1 Connection-Oriented Multiple Access (Pre-Assignment) 20
2.2.2 Demand Assignment Multiple Access (Demand-Assignment) 22
2.2.3 Contention-Oriented Multiple Access (Random Access) 27
2.3 Review of CRDSA Protocol 31
3 RA Scheme with Reservation for SATNETs 33
3.1 Two Barriers in the Advanced RA schemes 33
3.1.1 Critical Point 35
3.1.2 Capacity Efficiency 37
3.2 R-CRDSA: Reservation with CRDSA Scheme 39
3.2.1 Three Rules of R-CRDSA 40
3.2.2 Example of R-CRDSA 46
3.2.3 Comparing with DSA, CRDSA, and R-CRDSA 47
3.2.4 Implementation Considerations 48
3.3 Performance Analysis 49
3.3.1 System Model 51
3.3.2 Analytic CRDSA Throughput Upper Bound Derivation 52
3.3.3 Normalized Throughput of R-CRDSA 54
3.3.4 Normalized Efficiency of R-CRDSA 57
3.3.5 Simulation Results 58
3.4 Summary 63
4 Stability Analysis of R-CRDSA 64
4.1 Stability of Random Access Schemes 64
4.1.1 Related Works 64
4.1.2 Definition of Stability for RA Schemes 65
4.1.3 Source of Instability in RA channel 65
4.2 Stability of R-CRDSA 68
4.2.1 System Model 68
4.2.2 Drift Analysis 71
4.2.3 Comparison of Drift-Backlog for R-CRDSA 79
4.3 System Configuration Comparison for Stable Operation 84
4.3.1 Average Delay 85
4.3.2 Comparison of the Min. Average Backlog Time (Db) 88
4.3.3 Comparison of Max. Traffic Generation Probability (p0) 90
4.3.4 Comparison of Supportable User Population (M) 91
4.4 Summary 95
5 Conclusions and Suggestions for Future Work 97
References 101
