Joint Optimization of Energy Efficiency and Data Compression in TDMA-Based Medium Access Control for the IoT - Extended Version

Energy efficiency is a key requirement for the Internet of Things, as many sensors are expected to be completely stand-alone and able to run for years without battery replacement. Data compression aims at saving some energy by reducing the volume of data sent over the network, but also affects the quality of the received information. In this work, we formulate an optimization problem to jointly design the source coding and transmission strategies for time-varying channels and sources, with the twofold goal of extending the network lifetime and granting low distortion levels. We propose a scalable offline optimal policy that allocates both energy and transmission parameters (i.e., times and powers) in a network with a dynamic Time Division Multiple Access (TDMA)-based access scheme.Comment: 8 pages, 4 figures, revised and extended version of a paper that was accepted for presentation at IEEE Int. Workshop on Low-Layer Implementation and Protocol Design for IoT Applications (IoT-LINK), GLOBECOM 201

Fixed-point Processing for an IR Positioning System based on QADA Receivers

2022 IEEE 12th International Conference on Indoor Positioning and Indoor Navigation (IPIN), 5-8 September, 2022, Beijing, China.Indoor optical positioning systems have increased in popularity in recent years because they can provide centimeter accuracy in three dimensions (3D) utilizing light-emitting diodes (LEDs) and photoreceptors. This work presents the design of a positioning system, which is based on a set of four photoreceptors functioning as beacons at known places for a single LED to be positioned. However, it might be extended to additional emitters with some medium access control. The associated processing is explained, as well as the basic assumptions to be addressed when approaching its hardware implementation, such as the preliminary partitioning of tasks between hardware and software, and the fixed-point representation of the processing to be implemented in hardware. The system has been validated by simulation in a 2 × 2 × 3.4 m3 volume, yielding mean absolute errors around 0.004 m for the X and Y axes, and around 0.01 m for the Z-axis, as well as lower standard deviations than 0.004 m for the X and Y axes and 0.01 m for the Z-axis.Agencia Estatal de InvestigaciónUniversidad de Alcal

Implementing opportunistic spectrum access in LTE-Advanced

Long term evolution advanced (LTE-A) has emerged as a promising mobile broadband access technology aiming to cope with the increasing traffic demand in wireless networks. However, the enhanced spectral efficiency offered by LTE-A may become futile without a better management of scarce and overcrowded electromagnetic spectrum. In this sense, cognitive radio (CR) has been proposed as a potential solution to the problem of spectrum scarcity. Among all the mechanisms provided by CR, opportunistic spectrum access (OSA) aims at a dynamic and seamless use of certain licensed bands provided the licensee is not harmfully affected. This operation requires spectral awareness in order to avoid interferences with licensed systems. In spite of implementing some spectrum sensing mechanisms, LTE-A technology lacks other tools that are needed in order to improve the knowledge of the radio environment. This work studies the adoption of a Geo-located data base (Geo-DB) that cooperatively retrieves and maintains information regarding the location of unutilized portions of spectrum potentially available for OSA. Moreover, the potential benefit of this LTE-compliant OSA solution is evaluated using a calibrated simulation tool, by which numerical results allow us to optimally configure the system and show that the proposed opportunistic system is able to significantly improve its performance.The authors would like to thank the funding received from the Ministerio de Ciencia e Innovacion within the Project number TEC2011-27723-C02-02 and from the Ministerio de Industria, Turismo y Comercio TSI-020100-2011-266 funds. This article had been written in the framework of the CELTIC project CP08-001 COMMUNE. Study by X. Gelabert is funded by the BP-DGR 2010 scholarship (ref. 00192). The authors would like to acknowledge the contributions of their colleagues.Osa Ginés, V.; Herranz Claveras, C.; Monserrat Del Río, JF.; Gelabert, X. (2012). Implementing opportunistic spectrum access in LTE-Advanced. EURASIP Journal on Wireless Communications and Networking. 2012(99):1-17. https://doi.org/10.1186/1687-1499-2012-99S117201299Martín-Sacristán D, Monserrat JF, Cabrejas-Peñuelas J, Calabuig D, Garrigas S, Cardona N: On the way towards fourth-generation mobile: 3GPP LTE and LTE-Advanced. EURASIP J Wirel Commun Netw 2009, 2009: 1-10.Ratasuk R, Tolli D, Ghosh A: Carrier aggregation in LTE-Advanced. In IEEE 71st Vehicular Technology Conference (VTC 2010-Spring). Taipei; 2010:1-5.Wang H, Rosa C, Pedersen K: Performance of uplink carrier aggregation in LTE-advanced systems. In IEEE 72nd Vehicular Technology Conference Fall (VTC 2010-Fall). Ottawa; 2010:1-5.Tandra R, Sahai A, Mishra S: What is a spectrum hole and what does it take to recognize one? 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In Proc of the Fifth International Conference on Cognitive Radio Oriented Wireless Networks Communications (CROWNCOM). Cannes; 2010:1-5.IEEE Std 80221-2008: IEEE Standard for Local and Metropolitan Area Networks-Part 21: Media Independent Handover. 2009.3GPP TS 36133: Evolved Universal Terrestrial Radio Access (E-UTRA); Requirements for support of radio resource management.Sesia S, Baker M, Toufik I: LTE, the UMTS long term evolution: from theory to practice. Wiley, New Haven; 2009.Digham FF, Alouini MS, Simon MK: On the energy detection of unknown signals over fading channels. In IEEE International Conference on Communications, 2003 (ICC'03). Volume 5. Anchorage; 2003:3575-3579.Ghasemi A, Sousa ES: Collaborative spectrum sensing for opportunistic access in fading environments. In First IEEE International Symposium on New Frontiers in Dynamic Spectrum Access Networks (DySPAN). Baltimore; 2005:131-136.Gelabert X, Akyildiz IF, Sallent O, Agustí R: Operating point selection for primary and secondary users in cognitive radio networks. Comput Netw 2009, 53(8):1158-1170. 10.1016/j.comnet.2009.02.009Taniuchi K, Ohba Y, Fajardo V, Das S, Tauil M, Cheng YH, Dutta A, Baker D, Yajnik M, Famolari D: IEEE 802.21: media independent handover: features, applicability, and realization. IEEE Commun Mag 2009, 47: 112-120.3GPP TS 36305: Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Stage 2 functional specification of User Equipment (UE) positioning in E-UTRAN.3GPP TS 36355: Evolved Universal Terrestrial Radio Access; LTE Positioning Protocol (LPP).3GPP TS 36455: Evolved Universal Terrestrial Radio Access; LTE Positioning Protocol A (LPPa).Ren W, Zhao Q, Swami A: Power control in cognitive radio networks: how to cross a multi-lane highway. 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Rome; 2009:1-6.3GPP TS 36214: Physical layer; Measurements.Ofuji Y, Morimoto A, Abeta S, Sawahashi M: Comparison of packet scheduling algorithms focusing on user throughput in high speed downlink packet access. In 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications. Volume 3. Lis-boa; 2002:1462-1466.ITU-R ITU M2135: Guidelines for evaluation of radio interface technologies for IMT-Advanced 2008

A Novel Deep Learning Framework for Internal Gross Target Volume Definition from 4D Computed Tomography of Lung Cancer Patients

In this paper, we study the reliability of a novel deep learning framework for internal gross target volume (IGTV) delineation from four-dimensional computed tomography (4DCT), which is applied to patients with lung cancer treated by Stereotactic Body Radiation Therapy (SBRT). 77 patients who underwent SBRT followed by 4DCT scans were incorporated in a retrospective study. The IGTV_DL was delineated using a novel deep machine learning algorithm with a linear exhaustive optimal combination framework, for the purpose of comparison, three other IGTVs base on common methods was also delineated, we compared the relative volume difference (RVI), matching index (MI) and encompassment index (EI) for the above IGTVs. Then, multiple parameter regression analysis assesses the tumor volume and motion range as clinical influencing factors in the MI variation. Experimental results demonstrated that the deep learning algorithm with linear exhaustive optimal combination framework has a higher probability of achieving optimal MI compared with other currently widely used methods. For patients after simple breathing training by keeping the respiratory frequency in 10 BMP, the four phase combinations of 0%, 30%, 50% and 90% can be considered as a potential candidate for an optimal combination to synthesis IGTV in all respiration amplitudes

Analysing the EAP-TLS handshake and the 4-way handshake of the 802.11i standard

The IEEE 802.11i standard has been designed to enhance security in wireless networks. The EAP-TLS handshake aims to provide mutual authentication between supplicant and authentication server, and then derive the Pairwise Master Key (PMK). In the 4 -way handshake the supplicant and the authenticator use PMK to derive a fresh pairwise transient key (PTK). The PMK is not used directly for security while assuming the supplicant and authenticator have the same PMK before running 4- way handshake. In this paper, the EAP-TLS handshake and the 4-way handshake phases have been analysed with a proposed framework using Isabelle tool. In the analysis, we have found a new Denial-of-Service (DoS) attack in the 4-way handshake. The attack prevents the authenticator from receiving message 4 after the supplicant sends it out. This attack forces the authenticator to re-send the message 3 until time out and subsequently to de-authenticate supplicant. This paper has proposed improvements to the 4-way handshake to avoid the Denial-of-Service attack

Weighted proportional fairness and pricing based resource allocation for uplink offloading using IP flow mobility

Mobile data offloading has been proposed as a solution for the network congestion problem that is continuously aggravating due to the increase in mobile data demand. However, the majority of the state-of-the-art is focused on the downlink offloading, while the change of mobile user habits, like mobile content creation and uploading, makes uplink offloading a rising issue. In this work we focus on the uplink offloading using IP Flow Mobility (IFOM). IFOM allows a LTE mobile User Equipment (UE) to maintain two concurrent data streams, one through LTE and the other through WiFi access technology, that presents uplink limitations due to the inherent fairness design of IEEE 802.11 DCF by employing the CSMA/CA scheme with a binary exponential backoff algorithm. In this paper, we propose a weighted proportionally fair bandwidth allocation algorithm for the data volume that is being offloaded through WiFi, in conjunction with a pricing-based rate allocation for the rest of the data volume needs of the UEs that are transmitted through the LTE uplink. We aim to improve the energy efficiency of the UEs and to increase the offloaded data volume under the concurrent use of access technologies that IFOM allows. In the weighted proportionally fair WiFi bandwidth allocation, we consider both the different upload data needs of the UEs, along with their LTE spectrum efficiency and propose an access mechanism that improves the use of WiFi access in uplink offloading. In the LTE part, we propose a two-stage pricing-based rate allocation under both linear and exponential pricing approaches, aiming to satisfy all offloading UEs regarding their LTE uplink access. We theoretically analyse the proposed algorithms and evaluate their performance through simulations. We compare their performance with the 802.11 DCF access scheme and with a state-of-the-art access algorithm under different number of offloading UEs and for both linear and exponential pricing-based rate allocation for the LTE uplink. Through the evaluation of energy efficiency, offloading capabilities and throughput performance, we provide an improved uplink access scheme for UEs that operate with IFOM for uplink offloading.Peer ReviewedPreprin