Gwang-Ja Jin

Two-state routing protocol for maritime multi-hop wireless networks

The expensive satellite communication currently accessible from ships is ill equipped to meet the needs of a growing number of seafaring Internet users. In order to provide cheap and high-speed Internet access to ships, the radio coverage of existing broadband networks can be extended through a multi-hop network that provides wireless links between neighboring ships. One of the most important issues in such networks is the appropriate choice of a routing protocol that provides efficient and reliable communication. In this paper, a maritime two-state routing protocol for a multi-hop ship network is proposed that provides efficient and reliable communication with a minimum of overhead. The maritime path loss model considered for simulations and the mobility model used in this paper represent real traffic of ships. In this paper, the proposed routing protocol is compared to the leading alternatives and simulation results are presented to quantify the performance.

A modified AOMDV routing protocol for maritime inter-ship communication

In maritime communication, QoS problem caused by routing is very important. In this paper, we propose a method based on AOMDV protocol providing a route recovery mechanism when a link breaks in an active route to reduce lost packets. The results show that the proposed method can reduce packet loss ratio and delay time compared with the AOMDV.

The Modified Proportional Fair Packet Scheduling Algorithm for Multimedia Traffic in LTE System

The Long Term Evolution (LTE) system is already able to provide a various background of media to mobile users, including multimedia services such as audio, video, data. In fact, the High Speed Downlink Access plus (HSPA+) solution within LTE can greatly enhance bit rates on downlinks. However, the supporting for multimedia applications with different QoS requirements is not devised yet. Hence, in this paper we present an effective packet scheduling algorithm based on proportional fairness (PF) scheduling algorithms for LTE. We optimize traffic class weightings and instantaneous user data rates that are central to packet prioritization approach of packet scheduling. Finally, we evaluated and showed the performance of optimized scheduling algorithm through simulation of multimedia traffics being currently transmitted to users the over LTE links in a multi-cell environment.

Antenna with wide beamwidth and high return loss for UHF RFID reader

A circularly polarized antenna with a wide beamwidth and high return loss is presented. The antenna consists of four U-shaped metal strips sequentially rotated and fed with a 90° phase difference. The antenna is designed for UHF RFID applications, and the experimental results show that it has a wide beamwidth of over 114° at 915 MHz and high return loss of over 34 dB in the 902-928 MHz range.

A Modified AOMDV Routing Protocol for Maritime Inter-ship Communication

In maritime communication, QoS problem caused by routing is very important. In this paper, we propose a method based on AOMDV protocol providing a route recovery mechanism when a link breaks in an active route to reduce lost packets. The results show that the proposed method can reduce packet loss ratio and delay time compared with the AOMDV.