@conference{Louta20124909,

title = {Design of an effective QoS-aware mapping scheme using persistent allocation probing},

author = { M. Louta and P. Sarigiannidis and P. Nicopolitidis and G. Papadimitriou and M. Obaidat},

doi = {10.1109/ICC.2012.6364291},

year  = {2012},

date = {2012-01-01},

journal = {IEEE International Conference on Communications},

pages = {4909-4913},

abstract = {Mobile Worldwide Interoperability for Microwave Access (WiMAX) constitutes an attractive trademark for supporting wireless access to Intranets and the Internet. Scheduling and mapping processes are of paramount importance since they dramatically affect the network performance. This work endeavors to provide a robust mapping scheme for the downlink sub-frame with respect to various Quality of Service (QoS) constraints. Each downlink request creates rectangular regions, called Horizons, and the mapping technique applies a persistent probing of the Horizons recorded. The evaluation experiments conducted indicate that the scheme designed beneficially affects the system performance. © 2012 IEEE.},

keywords = {IEEE 802.16, mapping, OFDMA, QoS, WiMAX},

pubstate = {published},

tppubtype = {conference}

}

@conference{Sarigiannidis2011139,

title = {On effectively determining the downlink-to-uplink sub-frame width ratio for mobile WiMAX networks using spline extrapolation},

author = { P. Sarigiannidis and M. Louta and A. Michalas},

url = {https://www.researchgate.net/publication/221565459_On_Effectively_Determining_the_Downlink-to-Uplink_Sub-frame_Width_Ratio_for_Mobile_WiMAX_Networks_Using_Spline_Extrapolation},

doi = {10.1109/PCI.2011.44},

year  = {2011},

date = {2011-01-01},

journal = {Proceedings - 2011 Panhellenic Conference on Informatics, PCI 2011},

pages = {139-143},

abstract = {One of the most valuable design issues of the Worldwide Interoperability for Microwave Access (WiMAX) standard is its flexibility. It allows multiple downlink-to-uplink duration definitions concerning the width of the corresponding sub-frames, thus, the telecommunication companies and businesses are able to define the downlink-to-uplink width from 3:1 to 1:1 respectively to meet the traffic demands of the connected subscribers. However, the decision on defining the most appropriate ratio is not yet solved, since current efforts on developing scheduling and mapping schemes consider it as fixed. In this work, a novel adaptive mapping approach - based on cubic spline extrapolation - is proposed in order to dynamically determine the most appropriate downlink-touplink width ratio in accordance to the downlink and uplink traffic demands. The method proposed is evaluated through realistic simulation scenarios, whereas its performance is compared with static approaches maintaining a fixed ratio. The results indicate that the approach suggested succeeds noticeable improvements in terms of network service capabilities and bandwidth utilization. © 2011 IEEE.},

keywords = {extrapolation, IEEE 802.16, mapping, OFDMA, Splines, WiMAX},

pubstate = {published},

tppubtype = {conference}

}

@conference{Sarigiannidis2011353,

title = {Using learning automata for adaptively adjusting the downlink-to-uplink ratio in IEEE 802.16e wireless networks},

author = { A. Sarigiannidis and P. Nicopolitidis and G. Papadimitriou and P. Sarigiannidis and M. Louta},

url = {https://www.researchgate.net/publication/221504931_Using_learning_automata_for_adaptively_adjusting_the_downlink-to-uplink_ratio_in_IEEE_80216e_wireless_networks},

doi = {10.1109/ISCC.2011.5983863},

year  = {2011},

date = {2011-01-01},

journal = {Proceedings - IEEE Symposium on Computers and Communications},

pages = {353-358},

abstract = {IEEE 802.16e allows for flexibly defining the relation of the downlink and uplink sub-frames' width from 3:1 to 1:1, respectively. However, the determination of the most suitable ratio is left open to the network designers and the research community. Existing scheduling and mapping schemes are inflexibly designed. In this paper, a novel adaptive mapping scheme is proposed aiming to dynamically adjust the downlink-to-uplink ratio, following adequately the modification of the load requests with respect to both downlink and uplink directions. A learning automaton is exploited in order to sense the performance of the downlink and uplink mapping processes and to determine the most appropriate length ratio of both sub-frames in order to maximize the network performance. The suggested ratio determination scheme is evaluated through realistic scenarios and it is compared with static schemes that maintain a fixed ratio. The results show that our proposed scheme introduces considerable improvement, increasing the network's service ratio and reducing the bandwidth waste. © 2011 IEEE.},

keywords = {IEEE 802.16, Learning automata, mapping, OFDMA, WiMAX},

pubstate = {published},

tppubtype = {conference}

}

@conference{Sarigiannidis2010763,

title = {A novel fair mapping scheme for IEEE 802.16 downlink sub-frame},

author = { P.G. Sarigiannidis and M.D. Louta and P. Chatzimisios},

url = {https://www.researchgate.net/publication/221003449_A_novel_fair_mapping_scheme_for_IEEE_80216_downlink_sub-frame},

doi = {10.1109/ICUMT.2010.5676550},

year  = {2010},

date = {2010-01-01},

journal = {2010 International Congress on Ultra Modern Telecommunications and Control Systems and Workshops, ICUMT 2010},

pages = {763-768},

abstract = {A novel fair mapping scheme is proposed in this paper for the IEEE 802.16 downlink sub-frame. The mapping process is critical since it allocates the users' requests into the downlink sub-frame in order to be sent to the mobile stations. One of the most noticeable issues in this area lies on the fairness aspect. Giving that the mapping process defines the order and the way that the users' requests are being serviced, some users may be treated unfairly. In this work this issue is considered and a new mapping scheme is introduced. The proposed scheme encloses fair and more efficient mapping process, compared to the leading scheme, according to the presented simulation results. ©2010 IEEE.},

keywords = {Fairness, IEEE 802.16, mapping, OFDMA, Simulation},

pubstate = {published},

tppubtype = {conference}

}

@conference{Sarigiannidis20101243,

title = {Towards a QoS-aware IEEE 802.16 downlink sub-frame mapping scheme},

author = { P.G. Sarigiannidis and M. Louta and D.G. Stratogiannis and G.I. Tsiropoulos},

url = {https://www.researchgate.net/publication/233833066_Towards_a_QoS-Aware_IEEE_80216_downlink_sub-frame_mapping_scheme},

doi = {10.1109/GLOCOMW.2010.5700136},

year  = {2010},

date = {2010-01-01},

journal = {2010 IEEE Globecom Workshops, GC'10},

pages = {1243-1247},

abstract = {IEEE 802.16 (WiMAX) is considered as one of the most promising wireless access technologies supporting high-capacity and long-distance communications as well as user mobility. A problem that should be addressed in the context of multi-access communications is the efficient accommodation of traffic requests to the downlink subframe. The allocation operation in downlink sub-frame is not standardized, while only restrictions on the usage of downlink sub-frame's bandwidth are defined. The most noticeable restriction is the rectangular restriction, requiring all downlink allocations to be mapped in a two-dimensions rectangular shaping. This study is a first step towards defining a QoS-aware mapping scheme, prioritizing traffic requests in accordance with the strict delay requirements they pose. The mapping scheme applies horizon scheduling, permitting bursts to be scheduled efficiently and in a simple way, following the horizons as pilots. The QoS-aware mapping scheme is evaluated by means of simulation experiments, which indicate that the proposed scheme operates effectively and efficiently, by reducing the number of unserviced users and traffic requests, and the portion of the dropped real-time traffic. ©2010 IEEE.},

keywords = {Downlink mapping, IEEE 802.16, OFDMA, QoS, Simulation},

pubstate = {published},

tppubtype = {conference}

}

@conference{Sarigiannidis2010c,

title = {A novel adaptive mapping scheme for IEEE 802.16 mobile downlink framing},

author = { P.G. Sarigiannidis and G.I. Papadimitriou and P. Nicopolitidis and M.S. Obaidat and A.S. Pomportsis},

url = {https://www.researchgate.net/publication/221288841_A_Novel_Adaptive_Mapping_Scheme_for_IEEE_80216_Mobile_Downlink_Framing},

doi = {10.1109/GLOCOM.2010.5683645},

year  = {2010},

date = {2010-01-01},

journal = {GLOBECOM - IEEE Global Telecommunications Conference},

abstract = {IEEE 802.16 (WiMAX) constitutes one of the most promising broadband access technologies for high-capacity and high-distance wireless access networks, supporting user mobility. The contribution of this paper is twofold. Firstly, a novel mapping scheme for IEEE 802.16 Mobile standard is introduced, applying horizon mapping. Secondly, an efficient adaptive prediction-based scheme is devised, which is able to adjust the downlink sub-frame capacity, accordingly to the traffic load, since the standard allows the downlink-to-uplink subframe ratio to be changeable from 3:1 to 1:1. The novel adaptive horizon burst mapping (AHBM) scheme is evaluated by simulation experiments, which indicate that the proposed scheme operates effectively and efficiently, by reducing the number of unserved users, the number of unserved traffic requests, and the portion of wasted bandwidth. ©2010 IEEE.},

keywords = {Downlink mapping, IEEE 802.16, OFDMA, prediction},

pubstate = {published},

tppubtype = {conference}

}