• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.39-47
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• 2005

The range of hardware implementation increases in communication systems as high-speed processing is required for high data rate. In the broadband wireless access (BWA) system based on IEEE standard 802.16 the functions of higher part in the MAC layer to Provide data needed for generating MAC PDU are implemented in software, and the tasks from formatting MAC PDUs by using those data to transmitting the messages in a modem are implemented in hardware. In this paper, the interface hardware for efficient message exchange between MAC and PHY layers in the BWA system is designed. The hardware performs the following functions including those of the transmission convergence(TC) sublayer; (1) formatting TC PDU(Protocol data unit) from/to MAC PDU, (2) Reed-solomon(RS) encoding/decoding, and (3) resolving DL MAP and UL MAP, so that it controls transmission slot and uplink and downlink traffic according to the modulation scheme of burst profile. Also, it provides various control signal for PHY modem. In addition, the truncated binary exponential backoff (TBEB) algorithm is implemented in a subscriber station to avoid collision on contention-based transmission of messages. The VLSI architecture performing all these functions is implemented and verified in VHDL.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.95-98
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• 2004

In this paper, the hardware design of a transmission convergence sublayer(TC) for boradband wireless access system is described, which performs (1) formatting TC PDUs to MAC PDUs, (2) RS encoding/decoding, (3) providing various control signal to PHY modem. The TC hardware has been designed in VHDL, and successfully synthesized in an FPGA chip.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.837-840
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• 1999

In this paper, we design and verify the hardware circuit that performs PLCP(Physical Layer Convergence Protocol) protocol functions of physical layer in IEEE 802.11 frequency hopping WLAN(Wireless Local Area Network). Altera MAX＋PLUS I $I^{〔1〕}$ is used as a design tool. The designed circuit consists of control register module to interface with upper layer, FIFO module to transmit/receive data with upper layer, TX function module, and RX function module. It is verified that the developed circuit conforms well to the IEEE 802.11 standard specification and can support both 1Mbps and 2 Mbps transmission rate by simulation. The developed circuits can be utilized for the implementation of protocol processor in wireless LAN areas.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.235-236
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• 2006

IEEE 802.16 networks support mobile stations (MSs) to access broadband wireless networks while moving at a vehicular speed. However, IEEE 802.16 networks do not provide link layer native multicast capability because of point-to-multipoint connection characteristic. Due to this feature, it is not easy to adopt protocols or applications which need native link layer multicast capability. In order to solve the multicast support problem, we use the built-in LAN emulation feature of IEEE 802.16 which is based on Convergence Sublayer (CS). Our proposed operational procedures support not only the delivery of link local scope multicast packets, but also the delivery of non-link local scope multicast packets such as site local or global scope multicast packets. We also present the method of forming multicast Connection Identifier (CID) which is used to transport IP packets over IEEE 802.16 networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1941-1951
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• 1998

In this paper, hardware circuit that performs functions of IEEE 802.11 wireless LAN frequency hopping PLCP protocol is designed using 0.8 um CMOS cmn8a technology of the COMPASS. Transmission rate of the designed hardware is 1Mbps. The designed circuit have about 6300 gates and $2.5{\times}2.5mm^2$ area. In order to verify the circuit, two PLCP circuits are interconnected and frames are transmitted from one PLCP circuit to the other PLCP circuit. As a results of the simulation, we conclude that the designed PLCP circuit works well as the IEEE 802.11 standard specification.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.4015-4033
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• 2015

The future mobile networks consist of hyper-dense heterogeneous and small cell networks of same or different radio access technologies (RAT). Integrating mobile networks of different RATs to provide seamless and smooth mobility service will be the target of future mobile converged network. Generally, handover from high-speed networks to low-speed networks faces many challenges from application perspective, such as abrupt bandwidth variation, packet loss, round trip time variation, connection disruption, and transmission blackout. Existing inter-RAT handover solutions cannot solve all the problems at the same time. Based on the high-layer convergence sublayer design, a new receiver-aided soft inter-RAT handover is proposed. This soft handover scheme takes advantage of multihoming ability of multi-mode mobile station (MS) to smooth handover procedure. In addition, handover procedure is seamless and applicable to frequent handover scenarios. The simulation results conducted in UMTS-WiMAX converged network scenario show that: in case of TCP traffics for handover from WiMAX to UMTS, not only handover latency and packet loss are eliminated completely, but also abrupt bandwidth/wireless RTT variation is smoothed. These delightful features make this soft handover scheme be a reasonable candidate of mobility management for future mobile converged networks.