Random Access Scheme with Reservation for Next Generation Satellite Networks

Alternative Title
Lee, MinWoo
Alternative Author(s)
일반대학원 NCW학과
The Graduate School, Ajou University
Publication Year
satellite networkrandom accessmultiple accessNCW
Alternative Abstract
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.

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Graduate School of Ajou University > Department of Military Digital Convergence > 3. Theses(Master)
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