QoS Supported Dynamic Channel Scanning for Seamless Handovers in Wireless Networks

YOO, Sang-Jo,GOLMIE, Nada The Institute of Electronics, Information and Comm 2009 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.92 No.6

<P>Channel scanning is an important aspect of seamless handovers since it is required in order to find a target point of attachment (PoA). However, channel scanning in single radio devices may cause severe service disruptions with the current PoA so that the provided QoS will be further degraded during a handover. In this letter, we propose a dynamic channel scanning algorithm that supports QoS. Simulation results show that the proposed mechanism reduces the service disruptions and provides the desired QoS to users during the scanning period.</P>

Throughput study for admission control in IEEE 802.11 DCF with ARF

Kunho Hong,Sukyoung Lee,Golmie, N. IEEE 2009 IEEE communications letters Vol.13 No.6

<P>We propose an analytical approach to determining the admission of new stations to a WLAN operating in IEEE 802.11 distributed coordination function (DCF) with auto rate fallback (ARF). The proposed approach is based on a cross layer analytical model of how the throughput of existing stations in the WLAN is affected by admitting the new station in non-saturated as well as saturated traffic conditions. The effectiveness of the proposed approach is verified by simulations.</P>

Policy-based scanning with QoS support for seamless handovers in wireless networks

Yoo, Sang-Jo,Golmie, Nada John Wiley Sons, Ltd. 2010 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.10 No.3

<P>Supporting seamless handovers between different wireless networks is a challenging issue. One of the most important aspects of a seamless handover is finding a target network and point of attachment (PoA). This is achieved by performing a so-called channel scanning. In most handovers, such as between universal mobile telecommunications system (UMTS), wireless local area network (WLAN), and worldwide interoperability for microwave access (WiMAX), channel scanning causes severe service disruptions with the current PoA and degrades the quality of service (QoS) during the handover. In this paper, a new architecture for QoS supported scanning that can be generalized to different wireless networks is proposed. It employs two techniques. The first is for determining a policy-based order for the channel scanning sequence. With this technique, depending on the network costs and user requirements, the policy engine determines the channel scanning order for different network types and sets up a scanning sequence of PoAs for a given network type. This policy-based scanning order provides a faster discovery of the target PoA that meets the QoS demands of the user. The second technique consists of a QoS supported dynamic scanning algorithm where the scanning frequency and duration are determined based on the user QOS requirements. Most importantly, the scanning duration is scheduled to guarantee the user QoS requirements while the scan progresses. Simulation results show that the proposed mechanism achieves relatively short service disruptions and provides the desired quality to users during the scanning period. Copyright © 2009 John Wiley & Sons, Ltd.</P> <B>Graphic Abstract</B> <P>In this paper, a new architecture for QoS supported scanning that can be generalized to different wireless networks is proposed. It employs two techniques. The first is for determining a policy-based order for the channel scanning sequence depending on the network costs and user requirements. The second technique consists of a QoS supported dynamic scanning algorithm where the scanning frequency and duration are determined based on the user QoS requirements. <img src='wiley_img/15308669-2010-10-3-WCM774-gra001.gif' alt='wiley_img/15308669-2010-10-3-WCM774-gra001'> </P>

Predictive link trigger mechanism for seamless handovers in heterogeneous wireless networks

Yoo, Sang-Jo,Cypher, David,Golmie, Nada John Wiley Sons, Ltd. 2009 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.9 No.5

<P>Effective and timely link-layer trigger mechanisms can significantly influence the handover performance. The handover process will not perform the correct decision and execution unless adequate and timely link-layer trigger information is delivered. In this paper, a predictive link trigger mechanism for seamless horizontal and vertical handovers in heterogeneous wireless networks is proposed. Unlike previous link trigger algorithms based on pre-defined signal level thresholds, the link layer triggers in this study are adaptively and timely fired in accordance with the network conditions. Firstly, the time required to perform a handover is estimated based on the neighboring network conditions. Secondly, the time to trigger a Link_Going_Down to initiate a handover is determined using a least mean square linear prediction in which the prediction interval (k<SUB>h</SUB>) is dynamically determined based on the estimated handover time. An upper bound for the packet loss rate during a handover is derived for a Gaussian shadowing channel. A manner in which this approach can be applied to IEEE 802.21 is shown in media independent handover scenarios. Simulation results of the proposed predictive link triggering mechanism show that it provides a timely proactive handover. The packet loss rate observed in a Gaussian shadowing channel remains low during a handover. Copyright © 2008 John Wiley & Sons, Ltd.</P>

A New Call Admission Control Scheme for Heterogeneous Wireless Networks

Duk Kyung Kim,Griffith, David,Golmie, Nada IEEE 2010 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.9 No.10

<P>Call Admission Control (CAC) between heterogeneous networks, such as an integrated 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) network and a Wireless Local Area Network (WLAN), plays an important role to utilize the system resources in a more efficient way. In this paper, we propose that the preference to the WLAN is determined based on the traffic load in the WLAN and the location of the cellular users. Our analysis relies on a previous study that divides the 3G cellular coverage area into zones based on the amount of resources that are required to support a connection to a mobile user. Using this model, we derive new call blocking and handoff failure probabilities as well as new call and handoff attempt failure probabilities. Through simulations, we investigate proper preference settings by changing the WLAN load in a 3 ring-based sector with a WLAN hotspot.</P>

A Throughput Study for Channel Bonding in IEEE 802.11ac Networks

Kim, Mun-Suk,Ropitault, Tanguy,Lee, Sukyoung,Golmie, Nada IEEE 2017 IEEE communications letters Vol.21 No.12

<P>Several analytical models for the channel bonding feature of IEEE 802.11ac have previously been presented for performance estimation, but their accuracy has been limited by the assumptions that there are no collisions or all nodes are in saturated state. Therefore, in this letter, we develop an analytical model for the throughput performance of channel bonding in IEEE 802.11ac, considering the presence of collisions under both saturated and non-saturated traffic loads, and our numerical results were validated by a simulation study.</P>

A novel ring-based performance analysis for call admission control in wireless networks

Duk Kyung Kim,Griffith, D.,Golmie, N. IEEE 2010 IEEE communications letters Vol.14 No.4

<P>In Orthogonal Frequency Division Multiplex (OFDM) wireless networks such as 3GPP LTE and IEEE 802.16 WiMAX, the scheduler should allocate more resources to users with lower channel quality, such as users near the edge of the Base Station (BS) coverage area who are attempting handovers. In conventional queue-based models, this feature has not been considered in Call Admission Control (CAC) so far. In this letter, we propose a new ring-based model of the BS coverage area to allow a more detailed and accurate analysis. We determine mobility-related parameters such as call dropping probability due to mobility, and validate our results using simulations.</P>

Performance analysis of fast handover for proxy Mobile IPv6

Kim, M.S.,Lee, S.,Cypher, D.,Golmie, N. North-Holland [etc ; Elsevier Science Ltd 2013 Information sciences Vol.219 No.-

In Proxy Mobile IPv6 (PMIPv6), any involvement by the Mobile Node (MN) is not required, so that any tunneling overhead can be removed from over-the-air. However, during the PMIPv6 handover process, there still exists a period when the MN is unable to send or receive packets because of PMIPv6 protocol operations, suffering from handover latency and data loss. Thus, to reduce the handover latency and data loss in PMIPv6, Fast Handover for PMIPv6 (PFMIPv6) is being standardized in the IETF. Nevertheless, PFMIPv6 has a few weaknesses: (1) handover initiation can be false, resulting in the PFMIPv6 handover process done so far becoming unnecessary. (2) Extra signaling is introduced in setting up an IP-in-IP tunnel between the serving and the new Mobile Access Gateways (MAGs). Therefore, in this paper, we present our study on the protocol overhead and performance aspects of PFMIPv6 in comparison with PMIPv6. We quantify the signaling overhead and the enhanced handover latency and data loss by conducting a thorough analysis of the performance aspects. The analysis is very meaningful to obtain important insights on how PFMIPv6 improves the handover performance over PMIPv6, especially in a highway vehicular traffic scenario where Base Stations (BSs)/Access Points (APs) can be placed in one dimensional space and MN's movements are quasi one-dimensional, so that the degree of certainty for an anticipated handover is increased. Further, our analytical study is verified by simulation results.

Timely Effective Handover Mechanism in Heterogeneous Wireless Networks

Yoo, Sang-Jo,Cypher, David,Golmie, Nada Springer-Verlag 2010 WIRELESS PERSONAL COMMUNICATIONS Vol.52 No.3

Efficient MU-MIMO Beamforming Protocol for IEEE 802.11ay WLANs

Kim, Munsuk,Ropitault, Tanguy,Lee, Sukyoung,Golmie, Nada IEEE 2019 IEEE communications letters Vol.23 No.1

<P>IEEE 802.11ay supports multi-user multiple-input-multiple-output (MU-MIMO). However, the MU-MIMO beamforming training (BFT) is a time-consuming process for finding appropriate directional antenna patterns, and inefficient BFT results in a long training time. Thus, in this letter, we propose an algorithm that configures the transmit antenna with the aim of reducing the number of redundant transmissions during MU-MIMO BFT. Both analytic and simulation results show that our proposed algorithm can significantly reduce the training time.</P>