• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.10
• /
• pp.1889-1899
• /
• 2015

In this paper, we propose a multiple slot reservation scheme to transmit data rapidly in the satellite random access channel. In the R-CRDSA (Reservation scheme with Contention Resolution Diversity Slotted ALOHA), each satellite terminal can use only one slot in a frame. Therefore, many slots are wasting in the low traffic load and the satellite terminals which have large date needs many frame to transmit their data although there are unused slots. In the multiple slot reservation scheme, each satellite terminal transmits a packet with their data size and reserves many slots in the light of data size and slot reservation status. Therefore, each satellite terminal transmits their data faster than R-CRDSA. This is because they can reserve many slots in a frame. Furthermore, we simulate proposed scheme and validate the performance of proposed scheme.

• Journal of Advanced Navigation Technology
• /
• v.17 no.5
• /
• pp.497-505
• /
• 2013

In TETRA(TErrestrial Trunked RAdio) standard, TMO(Trunked Mode Operation) communicates with the UE through the base station and it has a higher priority than DMO(Direct Mode Operation) which communicates with UE directly for channel allocation. As a result, the UE needs an algorithm which restricts the frequency allocation by TMO so that DMO can have a successful communication within the network. However, the TETRA DMO standard does not consider this issue. In this paper, we propose an active DMO channel selection algorithm which allocates a channel based on some additional information such as channel usage state of TMO and channel utilization of DMO. The experimental results show that the proposed algorithm outperforms existing DMO channel allocation scheme in terms of the transmission efficiency.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1995.10a
• /
• pp.239-242
• /
• 1995

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1995.10a
• /
• pp.1014-1018
• /
• 1995

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1995.10a
• /
• pp.1008-1013
• /
• 1995

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1995.10a
• /
• pp.1003-1007
• /
• 1995

• Information and Communications Magazine
• /
• v.15 no.3
• /
• pp.65-76
• /
• 1998

• Information and Communications Magazine
• /
• v.17 no.2
• /
• pp.116-127
• /
• 2000

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1996.10a
• /
• pp.1198-1201
• /
• 1996

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.8
• /
• pp.965-973
• /
• 2016

As increase of IoT services in wireless communications, the performance evaluation is required to connects massive number of devices in LTE-A system. Existing performance analysis of 3GPP TR 37.868 is shown the limited results up to the number of devices only 30,000 in a cell. So, it is required the performance analysis according to various parameter values in the greater number of devices environment. In this paper, to evaluate the performance, we developed the new modules to simulate LTE-A random access procedures because of a limit that accommodate massive number of devices in existing LTE module. The simulator was developed by OPNET and it can support up to 100,000 devices per cell. This paper also represents the performance analysis results according to the number of preambles, the maximum number of preamble transmissions, backoff indicator and msg2 window size in the same environment with 3GPP TR 37.868. This results are expected to be utilized such as the transition to 5G network and standardization activities.