• ETRI Journal
• /
• v.34 no.3
• /
• pp.450-453
• /
• 2012

IEEE 802.11n standards introduced a mixed-mode format frame structure to achieve higher throughput with multiple antennas while providing backward compatibility with legacy systems. Although multi-input multi-output channel estimation was possible only with high-throughput long training fields (HT-LTFs), the proposed scheme utilizes a legacy LTF as well as HT-LTFs in a decision feedback manner to improve the accuracy of the estimates. It was verified through theoretical analysis and simulations that the proposed scheme effectively enhances the mean square error performance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2011.11a
• /
• pp.78-81
• /
• 2011

In this paper, we propose an additional data transmission scheme using multiple-antennas with backward compatibility for legacy ATSC (Advanced Television Systems Committee) terrestrial DTV (digital television) receivers. The proposed scheme improves the data rate and bit error rate performance compared to the conventional single antenna transmission scheme for additional data. Also, the proposed scheme guarantees backward compatibility for legacy ATSC DTV receivers.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2011.11a
• /
• pp.247-250
• /
• 2011

In this paper, we propose an additional data transmission scheme using multiple-antennas with backward compatibility for legacy ATSC (Advanced Television Systems Committee) terrestrial DTV (digital television) receivers. The proposed scheme improves the data rate and bit error rate performance compared to the conventional single antenna transmission scheme for additional data. Also, the proposed scheme guarantees backward compatibility for legacy ATSC DTV receivers.

• Proceedings of the IEEK Conference
• /
• 2003.11c
• /
• pp.208-211
• /
• 2003

기존 IEEE 802.11 MAC (1)에서는 Fairness를 보장하며 Resource를 제공하는 것을 목표로 동일한 DIFS, Back-off 알고리즘, Source가 같은 경우 동일한 Frame size등을 사용하는 Specification을 작성하여 구현한다. 최근 Home Network과 같은 특수한 Ad-Hoc 환경에서의 이런 Fairness Resource Usage가 오히려 기대 성능을 떨어뜨리는 결과를 가져오고 있다. 이에 802.11 MAC에서 Backward Compatibility를 유지하면서 Prioritized DIFS/Backoff/Frame를 통해 차등화된 서비스를 제공하는 메커니즘을 제안하고자 하는 것이 본 논문의 목표이다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.4
• /
• pp.769-776
• /
• 2016

TELNET is vulnerable to network attack because it was designed without considering security. SSL/TLS and SSH are used to solve this problem. However it needs additional secure protocol and has no backward compatibility with existing TELNET in this way. In this paper, we have suggested STELNET(Secured Telnet) which supports security functionalities internally so that has a backward compatibility. STELNET supports a backward compatibility with existing TELNET through option negotiation. On STELNET, A client authenticates server by a certificate or digital signature generated by using ECDSA. After server is authenticated, two hosts generate a session key by ECDH algorithm. And then by using the key, they encrypt data with AES and generate HMAC by using SHA-256. After then they transmit encrypted data and generated HMAC. In conclusion, STELNET which has a backward compatibility with existing TELNET defends MITM(Man-In-The-Middle) attack and supports security functionalities ensuring confidentiality and integrity of transmitted data.

• Journal of Broadcast Engineering
• /
• v.12 no.1 s.34
• /
• pp.2-10
• /
• 2007

We analyzed the receiving performance of the DVB-S2 transmission system in the BC(Backward Compatibility) mode. The transmitter employs the hierarchical modulation, and the receiver can be implemented by the direct demodulation or the hierarchical demodulation. The performance of each demodulation scheme is analyzed by a statistical method and a computer simulation for the AWGN and nonlinear channels. The ratio of the LP/HP streams which is proper in the domestic satellite broadcasting environments, is also suggested.

• Journal of Korea Multimedia Society
• /
• v.19 no.3
• /
• pp.595-602
• /
• 2016

With the evolution and development of many kinds of healthcare devices and techniques, u-health standards have emerged as a major issue. Yet, most legacy medical devices and systems are still being used without deployment of the standards. Therefore, it is required to support backward compatibility for u-health standard-compliant systems to communicate with legacy non-standard medical and healthcare devices. This paper proposes a new scheme to support backward compatibility of IEEE 11073 system by adding a codec module to IEEE 11073 agent. The codec converts data sent by non-standard health devices to IEEE 11073 MDER data. Plus, we implemented the proposed IEEE 11073 agent with an Intel Edison board which is one of popular open source H/W platforms. The IEEE 11073 manager of the proposed system can monitor and control legacy non-standard devices through the proposed agent system. In our experimental results, we examined the proposed system can support interoperability between u-health standard and non-standard devices and contribute to the growth and expansion of u-health services.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.3
• /
• pp.45-58
• /
• 2023

KVMF(Korean Variable Message Format) 1.0 protocol is the Army's standard tactical datalink protocol that defines standard messages and communication methods to enable data communication between various weapon systems through bitwise variable message processing. The protocol has been applied to a variety of Army weapon systems over the past decade and has contributed to upgrade the Army's operational capabilities by enabling the implementation of Network Centric Warfare (NCW), the core of modern warfare. Since the KVMF 1.0 protocol was applied, new weapon systems with new technologies have been introduced over time, and new weapon systems have new messages based on the characteristics of the weapon system. As a result, compatibility problems arose due to different message versions with existing weapon systems, and it was expected that these problems would continue to emerge in the future, considering the need for continuous message revisions. Therefore, it became necessary to solve this problem, so this paper proposed a KVMF 2.0 protocol design that guarantees compatibility between forward and backward versions. In this paper, we implemented the design as SW, and confirmed that the design worked successfully by test between forward and backward versions on test environment. Therefore, when the KVMF 2.0 protocol design is applied to a weapon system, we can expect that the weapon system can be compatible with the forward and backward versions working with the existing weapon systems as well as with the future weapon systems.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.16 no.2
• /
• pp.27-33
• /
• 2020

Backward compatibility is one of the key issues for radio equipment supporting IEEE 802.11, the typical wireless local area networks (WLANs) communication protocol. For a successful packet decoding with the backward compatibility, the frame format detection is a core precondition. This paper presents a novel frame format detection method based on a deep learning procedure for WLANs affiliated with IEEE 802.11. Considering that the detection performance of conventional methods is degraded mainly due to the poor performances in the symbol synchronization and/or channel estimation in low signal-to-noise-ratio environments, we propose a novel detection method based on convolutional neural network (CNN) that replaces the entire conventional detection procedures. The proposed deep learning network provides a robust detection directly from the receive data. Through extensive computer simulations performed in the multipath fading channel environments (modeled by Project IEEE 802.11 Task Group ac), the proposed method exhibits superb improvement in the frame format detection compared to the conventional method.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.12A
• /
• pp.1375-1379
• /
• 2004

In this paper, we propose a new preamble structure for channel estimation in a MIMO OFDM-based WLAN System. Moreover, both the backward compatibility with IEEE 802.11a system and low overhead are considered for the preamble design. Simulation results show that the proposed preamble has low overhead and is obtained the good performance gain for channel estimation.