Soonchoul Kim

A novel protocol for downloadable CAS

This paper presents a novel protocol for downloadable conditional access system (DCAS) which can securely download conditional access (CA) software via bidirectional communication channel. The proposed DCAS protocol uses pre-assigned keys and certificates for mutual authentication between a DCAS headend and DCAS host, and then it shares a session key for encrypting and decrypting CA software to be downloaded to a DCAS host. In order to verify the stability and effectiveness of the proposed protocol, we implement the DCAS protocol simulator. It can emulate the function of DCAS entities and the process of messages for mutual authentication, session key sharing and code downloading. Finally, experimental results indicate that the proposed protocol satisfies the design requirements for DCAS1.

QoS provisioning in domain based mobile IP networks

In this paper, we propose a scalable domain-level call admission control (CAC0 algorithm supporting a novel dynamic reservation method in mobile IP (MIP) enable Internet. MIP tunnels enable for a mobile node to move to another subnet on a session. In order to prevent a service quality from being degraded in MIP networks, it is necessary to deliberate the quality of service (QoS) provisioning on the MIP tunnels especially for roaming mobile nodes (MNs) to foreign networks Our CAC algorithm keeps a handoff dropping probability (HDP) below a pre-defined value without regard to overloads of mobility agents (MAs). Our proposed scheme uses the number of calls that will be handed off from neighboring MAs and the number of calls in the current MA. We assume that each class has both a HDP and a desired bandwidth. The proposed admission control algorithm can be expanded to serve not only single class but also multi-class with different QoS requirements. Furthermore, we introduce an aggregated dynamic resource allocation method to reflect incoming call patterns and to reduce the number of reservation signals for the tunnels which can cause the increase in network traffics and the data loss during the handoff processing. We show that our scheme guarantees the given HDP and reduces the number of reservation signals comparing trunk reservation methods.

Delivery of New TTI Services over Terrestrial DMB and a Bidirectional network

This paper proposes the network structure and service model to deliver new traffic and travel information (TTI) services over terrestrial digital multimedia broadcasting (T-DMB) and a bidirectional network. We have newly specified a POI (point-of-interest) and a NWS (news information) application services which are perfectly compatible with TPEG (transport protocol expert group) protocols, and implemented T-DMB based TTI systems including TPEG encoder/decoder and a return-channel server system through CDMA as a bidirectional network. In the real-field environment as verifying the proposed services and systems above, we showed their stability and effectiveness by the excellent results in this paper.

Method for efficient CA software provisioning in downloadable conditional access system

A downloadable conditional access system (DCAS) focuses on transmitting conditional access (CA) software into a set-top-box (STB) securely via a bi-directional communication channel. This paper presents the method to provision CA software onto STBs efficiently for the purpose. In order to achieve this goal, we defined the DCAS policy on CA softwares configuration and downloading method, and designed DCAS headend servers which execute authentication and downloading according to the DCAS policy. Especially, a policy server (DPS) which plays an important role of generating and distributing the policy, is presented in detail. Also we implemented the DCAS system and showed the stability and effectiveness by verifying the implemented results in a testbed1.

Design and implementation of headend servers for downloadable CAS

This paper presents the design and implementation of headend servers for a downloadable conditional access system (DCAS) that can securely transmit CA code via a bi-directional communication channel. To design DCAS headend server, we define core functions to be performed in headend and categorize them into four sections such as authentication, provisioning, personalization and key management. Using this classification, system architecture for DCAS headend and functional block for each server are designed. DCAS headend servers based on an enhanced DCAS protocol are implemented. In order to verify the stability and effectiveness of the implemented headend servers, we construct a test-bed using them and a legacy cable headend system in a laboratory. The experimental results show that the DCAS headend servers are well designed.

Bidirectional Location Based Services Using Terrestrial-DMB and Wireless Communication Network

This paper presents a new bidirectional location based service (LBS) using terrestrial-digital multimedia broadcasting (T-DMB) and wireless communication network. We propose a new bidirectional POI (point-of-interest) application interoperable with TPEG protocol, and introduce the POI data server/client in T-DMB network and the bidirectional TTI contents server/host server in wireless communication network The receiving platform based on laptop computer is connected to T-DMB receiver and CDMA modem simultaneously, and it includes the TPEG decoder implemented by using the proposed protocol. The stability and effectiveness of the proposed protocol is verified through the field test.

A Novel TSI application Based on TPEG using T-DMB

The demand of travel and traffic information (TTI) service has dramatically increased due to rapid increment in the number of vehicles and population of frequently traveling on long weekends. In order to satisfying such a demand, a transport protocol experts group (TPEG) protocol was developed. However, merely two TPEG applications were standardized up to now. This paper presents a novel application, traffic status image information (TSI) application compatible to the existing TPEG protocol, which can be provided in T-DMB network. To verify the stability of TSI protocol, we implemented TSI data server/client, and T-DMB receiver with TSI decoder. Through an experimental broadcasting in the local DMB network, it is shown that the proposed application operates stably and effectively in the verification receiver.

Design and Implementation of T-DMB Receiver for Offering Traffic and Traveler Information

This paper introduces T-DMB (terrestrial digital multimedia broadcasting) receiver to provide TTI (traffic and traveler information) service through T-DMB signal. TTI service is one of the most popular services among the data services based on T-DMB, because many people need real time traffic information to avoid the traffic jam caused by the rapid increase in the traffic volume. Many travelers also want travel information around the interested point to visit. In order to satisfy these demands, we developed T-DMB receiver for TTI service based on T-DMB system having high performance in mobility and reception. This receiver can receive two kinds of services simultaneously, and so we can get TTI service while watching the video service through T-DMB in a car. In this paper, we describe the design and implementation of the receiver and then show the TTI service, which includes RTM (road traffic message), PTI (public transport information), POI (point of interest) and NEWS.

An ATSC 3.0-based scheduling and signaling system for hybrid broadcasting services

This paper introduces a design and implementation of a scheduling and signaling system for an ATSC 3.0 based hybrid broadcasting service. We describe the creation of the hybrid service scheduling information and the generation of service signaling data, including LLS and SLS on ROUTE/DASH basis hybrid delivery.

S-DASH: A new transmission mechanism for IP-based digital broadcasting systems

ATSC 3.0 is a next-generation terrestrial broadcast standard that transmits UHD media content by DASH segment file, not media frame unit. The size of DASH segment files varies even though they have the same quality and playback time. In other words, the sizes of DASH segment files basically burst. Moreover, a DASH segment file size burst more due to the amount of UHD media, which is larger than HD media. However, the bandwidth of broadcast system is limited and transmits media as CBR. Therefore, there are problems of delays and resource efficiency when the segment files with large variability are transmitted through the terrestrial broadcasting. In order to reduce delays, this paper proposes Server DASH (S-DASH). S-DASH selects and transmits the proper quality of a DASH segment file among the various qualities of DASH dataset by a broadcast server. Simulation results show that S-DASH can reduce delays.