• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1786-1795
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• 2006

Portable Internet extended from wireless LAN has a large cell size, similar to a wireless mobile communication. and can provide the seamless service which offers middle-low speed mobility. IEEE 802.16e, the international standard of Portable Internet, uses PKMv2 protocol for authorization and key exchange between a MSS and a BS. This paper proposes a new protocol based on PKMv2, which can provide that MSS is able to do fast authorization with a new BS when soft handover is occurred in a MSS. Our protocol can carry out fast authorization because of reducing the number of messages and parameter exchange, public key encryption and signature in wireless network more than the previous works. It also prevents eavesdropping from an external attacker and keeps the security against impersonation attacks for both a MSS and a BS.

• ETRI Journal
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• v.36 no.4
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• pp.554-563
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• 2014

The burgeoning growth of real-time applications, such as interactive video and VoIP, places a heavy demand for a high data rate and guarantee of QoS from a network. This is being addressed by fourth generation networks such as Long-Term Evolution (LTE). But, the mobility of user equipment that needs to be handed over to a new evolved node base-station (eNB) while maintaining connectivity with high data rates poses a significant challenge that needs to be addressed. Handover (HO) normally takes place at cell borders, which normally suffers high interference. This inter-cell interference (ICI) can affect HO procedures, as well as reduce throughput. In this paper, soft frequency reuse (SFR) and multiple preparations (MP), so-called SFRAMP, are proposed to provide a seamless and fast handover with high throughput by keeping the ICI low. Simulation results using LTE-Sim show that the outage probability and delay are reduced by 24.4% and 11.9%, respectively, over the hard handover method - quite a significant result.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.804-810
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• 2002

The code division multiple access(CDMA) system capacity is limited by the amount of interference of the system. To reduce the unnecessary interference, this paper proposes optimized cell identification codes for site selection diversity transmission(SSDT) power control in wideband code division multiple access system of third generation partnership project(3GPP). The main objective of SSDT power control is to transmit on the downlink from the primary cell, and thus reducing the interference caused by the multiple transmission. In order to select a primary cell, each cell is assigned a temporary identification(ID) and user equipment(UE) periodically informs a primary cell ID to the connecting cells during soft handover. The non-primary cells selected by UE do not transmit the dedicated physical data channel(DPDCH) to reduce the interference. A major issue with the SSDT technology is the impact of uplink symbol errors on its performance. These errors can corrupt the primary ID code and this may lead to wrong decoding in the base station receivers. The proposed SSDT cell ID codes are designed to minimize the problem and to be easily decoded using simple fast Hadamard transformation(FHT) decoder.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.1
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• pp.38-55
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• 2013

Wireless network systems provide fast data transmission rates and various services to users of mobile devices such as smartphones and smart pads. Because many people use high-performance mobile devices, the use of real-time multimedia services is increasing rapidly. However, the preoccupation of resources by real-time traffic users is causing harm to other services-for example, frequent call interference, lowered service quality, and poor network performance. This paper suggests a resource allocation algorithm for effective traffic service support in a hybrid network. The main objective is to obtain an optimum value of data rates by comparing user requirements with the amount of resources that can be allocated. A new mechanism based on Adaptive-Quality of Service (QoS) and a monitoring system based on Queue-Aware are proposed. Adaptive-QoS supports effective resource control according to the type of traffic service, and the monitoring system based on Queue-Aware measures the amount of resources in order to calculate the maximum that can be allocated. We apply our algorithm to a test system and use Qualnet 4.5.1 to evaluate its performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.872-875
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• 2005

Portable Internet extended from wireless LAN has a large cell size, similar to a wireless mobile communication, and can provides the seamless service which offers middle-low speed mobility. IEEE 802.16e, the international standard of Portable Internet, uses PKMv2(Privacy Key Management) protocol for authorization and key exchange between a MSS(Mobile Subscriber Station) and a BS(Base Station). This paper first reviews and studies overall security architecture of TTA HPi standard and IEEE 802.16e which supports mobility based on WMAN(Wireless Metropolitan Area Network) standard(IEEE 802.16)