Yongho Seok

Bio: Yongho Seok is an academic researcher from MediaTek. The author has contributed to research in topics: Frame (networking) & Communication channel. The author has an hindex of 46, co-authored 405 publications receiving 8031 citations. Previous affiliations of Yongho Seok include French Institute for Research in Computer Science and Automation & LG Electronics.

Optimal multi-sink positioning and energy-efficient routing in wireless sensor networks

Abstract: In wireless sensor networks, the sensors collect data and deliver it to a sink node. Most of the existing proposals deal with the traffic flow problem to deliver data to the sink node in an energy-efficient manner. In this paper, we extend this problem into a multi-sink case. To maximize network lifetime and to ensure fairness, we propose (i) how to position multiple sink nodes in a sensor network and (ii) how to route traffic flow from all of the sensors to these multiple sink nodes. Both of the problems are formulated by the linear programming model to find optimal locations of the multiple sink nodes and the optimal traffic flow rate of routing paths in wireless sensor networks. The improved lifetime and fairness of our scheme are compared with those of the multi-sink aware minimum depth tree scheme.

Method and apparatus for accessing channel in wlan system

Abstract: 본 발명은 무선 통신 시스템에 대한 것으로, 보다 상세하게는 무선랜 시스템에서 채널에 액세스하는 방법 및 장치가 개시된다 본 발명의 일 실시예에 따른 무선 통신 시스템의 스테이션(STA)에서 채널 동기화를 수행하는 방법은, 상기 STA의 채널 액세스가 허용되는 하나 이상의 슬롯에 대한 설정 정보를 액세스 포인트(AP)로부터 수신하는 단계; 상기 하나 이상의 슬롯의 슬롯 경계에서 상기 AP로부터 동기 프레임을 수신하는 단계; 및 상기 동기 프레임에 기초하여 상기 채널 동기화를 수행하는 단계를 포함하고, 상기 동기 프레임은 NDP(Null Data Packet) 프레임일 수 있다

Cross-layer architecture for adaptive video multicast streaming over multirate wireless LANs

Abstract: Multicast video streaming over multirate wireless LANs imposes strong demands on video codecs and the underlying network. It is not sufficient that only the video codec or only the underlying protocols adapt to changes in the wireless link quality. Research efforts should be applied in both and in a synchronized way. Cross layer design is a new paradigm that addresses this challenge by optimizing communication network architectures across traditional layer boundaries. This paper presents cross-layer architecture for adaptive video multicast streaming over multirate wireless LANs where layer-specific information is passed in both directions, top-down and bottom-up. The authors jointly consider three layers of the protocol stack: the application, data link and physical layers. The authors analyze the performance of the proposed architecture and extensively evaluate it via simulations. The results show that the real-time video quality of the overall system can be greatly improved by cross-layer signaling.

Method and apparatus for transmitting control information in wlan system

Abstract: There is provided a method of transmitting control information in a Wireless Local Area Network (WLAN) system, comprising transmitting first control information by means of cyclic shift delay diversity beam-forming and transmitting second control information. The first control information comprises information necessary for each of a plurality of target stations of the second control information to receive the second control information. The second control information beamformed and transmitted to the plurality of target stations.

Scanning procedure in wireless lan, station supporting the same, and frame format therefor

Abstract: Provided is a scan procedure in a wireless local access network, and a station and frame format for the scan procedure. In the scan procedure, a second station receives from a first station a probe request frame which comprises a Homogeneous Extended Service Set Identifier (HESSID) field containing a desired HESSID of the first station and a network type field containing a desired network type of the first station. And, the second station transmits a probe response frame to the first station in response to the probe request frame in case that the HESSID field in the probe request frame is set to a wildcard HESSID or the HESSID of a second station which received the probe request frame, and the network type field in the probe request frame is set to a wildcard network type or the network type of the second station.

User terminal, radio base station and radio communication method

Abstract: The present invention is designed to provide a user terminal, a radio base station and a radio communication method of novel structures that can achieve a good communication environment. A radio base station non-orthogonal-multiplexes downlink signals for a plurality of user terminals over a given radio resource, a user terminal having received the downlink signals for the plurality of user terminals decodes downlink signal for another user terminal, judges whether or not the downlink signal for the other user terminal has been successfully received, based on the decoding result of the downlink signal, reports a judgement result as to whether or not the downlink signal for the other user terminal has been successfully received and a judgement result as to whether or not a downlink signal for the user terminal has been successfully received, to the radio base station, and then the radio base station executes retransmission control of downlink signals based on reports from the user terminal.

A Survey and Tutorial of RFID Anti-Collision Protocols

Abstract: RFID technologies have revolutionized the asset tracking industry, with applications ranging from automated checkout to monitoring the medication intakes of elderlies. In all these applications, fast, and in some cases energy efficient, tag reading is desirable, especially with increasing tag numbers. In practice, tag reading protocols face many problems. A key one being tag collision, which occurs when multiple tags reply simultaneously to a reader. As a result, an RFID reader experiences low tag reading performance, and wastes valuable energy. Therefore, it is important that RFID application developers are aware of current tag reading protocols. To this end, this paper surveys, classifies, and compares state-of-the-art tag reading protocols. Moreover, it presents research directions for existing and future tag reading protocols.

Physical layer frame format for WLAN

Abstract: In a method for generating a data unit conforming to a first communication protocol, a first field and a second field to be included in a preamble of the data unit are generated. The first field includes a first set of one or more information bits that indicate a duration of the data unit and is formatted such that the first field allows a receiver device that conforms to a second communication protocol to determine the duration of the data unit. The second field includes a second set of one or more information bits that indicate to a receiver device that conforms to the first communication protocol that the data unit conforms to the first communication protocol. The first field and the second field are modulated using a modulation scheme specified for a field corresponding to the first field and the second field, respectively, by the second communication protocol.

From QoS to QoE: A Tutorial on Video Quality Assessment

Abstract: Quality of experience (QoE) is the perceptual quality of service (QoS) from the users' perspective. For video service, the relationship between QoE and QoS (such as coding parameters and network statistics) is complicated because users' perceptual video quality is subjective and diversified in different environments. Traditionally, QoE is obtained from subjective test, where human viewers evaluate the quality of tested videos under a laboratory environment. To avoid high cost and offline nature of such tests, objective quality models are developed to predict QoE based on objective QoS parameters, but it is still an indirect way to estimate QoE. With the rising popularity of video streaming over the Internet, data-driven QoE analysis models have newly emerged due to availability of large-scale data. In this paper, we give a comprehensive survey of the evolution of video quality assessment methods, analyzing their characteristics, advantages, and drawbacks. We also introduce QoE-based video applications and, finally, identify the future research directions of QoE.

Method and apparatus for supporting coordinated orthogonal block-based resource allocation (cobra) operations

Abstract: A method and apparatus may be configured to support coordinated orthogonal block-based resource allocation (COBRA) operations. An access point (AP) may be configured to indicate to a plurality of stations (STA)s that it may support COBRA. Each WTRU may be configured to indicate to the AP that it can support COBRA as well. The AP may be configured to transmit a COBRA controller information element (IE) comprising a plurality of fields to each of the WTRUs. Each WTRU may be configured to transmit a COBRA controllee IE comprising a plurality of fields. STA grouping management, group maintenance, channel access, beamforming, sounding and frequency and synchronization procedures are also described.