Cheol-Hye Cho

Interference-based channel assignment for DS-CDMA cellular systems

Link capacity is defined as the number of channels available in a link. In direct-sequence code-division multiple-access (DS-CDMA) cellular systems, this is limited by the interference present in the link. The interference is affected by many environmental factors, and, thus, the link capacity of the systems varies with the environment. Due to the varying link capacity, static channel assignment (SCA) based on fixed link capacity is not fully using the link capacity. This paper proposes a more efficient channel assignment based on the interference received at the base station (BS). In the proposed algorithm, a channel is assigned if the corresponding interference margin is less than the allowed interference, and, thus, channels are assigned adaptively to dynamically varying link capacity. Using the proposed algorithm yields more channels than using SCA in such an environment changes with nonhomogeneous traffic load or varying radio path loss. The algorithm also improves service grade by reserving channels for handoff calls.

Detecting a large number of objects in real-time using apache storm

Object detection is an important function for intelligent multimedia processing, but its computational complexity prevented its pervasive uses in consumer electronics. To process large-scale datasets in real-time, more resources and reliable infrastructures are required for spreading the data and running the applications across multiple machines in parallel. In order to detect a large number of objects in real-time, a task-parallel processing framework based on Storm is proposed.

BER (Bit Error Rate) performance according to the FFT input bit resolution in WiBro system

This paper finds the optimum input bit size of FFT engine in WiBro system through the uncoded-BER performances of computer simulation.

The development of video streaming system for iOS based smart device using Scalable Video Coding

In this paper, we propose video streaming system for iOS-based smart device using Scalable Video Coding (SVC).

3D image transmission technology for mobile IPTV

Recently mobile IPTV service becomes primary service to boost sluggish IT industry. Also 3D image seems to be more prominent in broadcasting service. Therefore 3D image service over mobile IPTV service network will appear as key converging telecommunications and broadcasting service. In order to provide 3D image in wireless access network, its necessary to enhance the capacity of wireless access network approximately 2 times, also operators should maximize the efficiency of radio resources usage ensuring QoS/QoE to users. But its difficulty to enhance the radio capacity of wireless access network. Therefore its necessary to use limited radio resource efficiently. In this paper 3D image transmission technology in mobile IPTV network is suggested to increase an ARPU in communication industry.

Comparison of traffic performance predictions for three different handoff-region models

A comparison of traffic performance predictions is shown for three different handoff-region models. The first model is based on a statistical approach assuming an exponential distribution of the handoff-region dwell time. The other two models are newly proposed and based on the fact that the distribution of the dwell-time in the handoff region can be derived only using a priori cell parameters such as cell geometry, mobile velocity distribution, channel numbers and etc. In the second model, the distribution of the dwell-time in the handoff region has been derived in closed form, while the handoff region is approximated as a rectangle. In the third model, no approximation on the geometry of the handoff region has been made, while the handoff dwell-time distribution is expressed in an integral form.

A software fault detection and recovery in CDMA systems

This paper describes an approach to software fault detection and recovery in CDMA systems, which is based on the sanity monitoring and auditing techniques. Sanity monitoring is a fault tolerance technique in a distributed system. It detects and recovers from software faults. We discuss how to identify performance classes and fault types for processes, and how to locate and isolate faults. An audit program detects and recovers from data errors in communication systems such as telephone switches. It is adapted to distributed systems. We discuss data error detection and recovery methods for CDMA systems that also use OS primitives.