Journal articles: 'TDMA'

1

Massling, A., N. Niedermeier, T. Hennig, E. O. Fors, E. Swietlicki, M. Ehn, K. Hämeri, et al. "Results and recommendations from an intercomparison of six Hygroscopicity-TDMA systems." Atmospheric Measurement Techniques 4, no. 3 (March 8, 2011): 485–97. http://dx.doi.org/10.5194/amt-4-485-2011.

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Abstract. The performance of six custom-built Hygrocopicity-Tandem Differential Mobility Analyser (H-TDMA) systems was investigated in the frame of an international calibration and intercomparison workshop held in Leipzig, February 2006. The goal of the workshop was to harmonise H-TDMA measurements and develop recommendations for atmospheric measurements and their data evaluation. The H-TDMA systems were compared in terms of the sizing of dry particles, relative humidity (RH) uncertainty, and consistency in determination of number fractions of different hygroscopic particle groups. The experiments were performed in an air-conditioned laboratory using ammonium sulphate particles or an external mixture of ammonium sulphate and soot particles. The sizing of dry particles of the six H-TDMA systems was within 0.2 to 4.2% of the selected particle diameter depending on investigated size and individual system. Measurements of ammonium sulphate aerosol found deviations equivalent to 4.5% RH from the set point of 90% RH compared to results from previous experiments in the literature. Evaluation of the number fraction of particles within the clearly separated growth factor modes of a laboratory generated externally mixed aerosol was done. The data from the H-TDMAs was analysed with a single fitting routine to investigate differences caused by the different data evaluation procedures used for each H-TDMA. The differences between the H-TDMAs were reduced from +12/−13% to +8/−6% when the same analysis routine was applied. We conclude that a common data evaluation procedure to determine number fractions of externally mixed aerosols will improve the comparability of H-TDMA measurements. It is recommended to ensure proper calibration of all flow, temperature and RH sensors in the systems. It is most important to thermally insulate the aerosol humidification unit and the second DMA and to monitor these temperatures to an accuracy of 0.2 °C. For the correct determination of external mixtures, it is necessary to take into account size-dependent losses due to diffusion in the plumbing between the DMAs and in the aerosol humidification unit.

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Nilsson, E., E. Swietlicki, S. Sjogren, J. Löndahl, M. Nyman, and B. Svenningsson. "Development of an H-TDMA for long-term unattended measurement of the hygroscopic properties of atmospheric aerosol particles." Atmospheric Measurement Techniques Discussions 2, no. 2 (April 15, 2009): 1057–73. http://dx.doi.org/10.5194/amtd-2-1057-2009.

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Abstract. A new hygroscopic tandem differential mobility analyzer (H-TDMA) has been constructed at Lund University within the frameworks of the EU FP6 Infrastructure Project EUSAAR (http://www.eusaar.org/). The aim of this coordinated H-TDMA development is to design and evaluate a new generation of H-TDMAs that are capable of conducting long term measurements of the hygroscopic growth and state of mixing of sub-micrometer atmospheric aerosol particles at the EUSAAR aerosol super-sites across Europe. The H-TDMA constructed for this project has been validated with respect to hygroscopic growth factor, stability of relative humidity (RH), temperature stability and its ability to operate unattended for longer periods of time. When measuring growth factors of ammonium sulphate, the new H-TDMA system was found to measure within a growth factor deviation of ±0.05 compared to previously recorded data by Tang et al. (1994). The long term RH of the system has been found stable at 90.0% with a standard deviation of ±0.23% and an average temperature variability of the second DMA less than ±0.1 K. Daily automated ammonium sulphate measurements have validated the ambient measurements. The instrument is operated at the EMEP/EUSAAR background station Vavihill in the southern part of Sweden.

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Nilsson, E., E. Swietlicki, S. Sjogren, J. Löndahl, M. Nyman, and B. Svenningsson. "Development of an H-TDMA for long-term unattended measurement of the hygroscopic properties of atmospheric aerosol particles." Atmospheric Measurement Techniques 2, no. 1 (June 30, 2009): 313–18. http://dx.doi.org/10.5194/amt-2-313-2009.

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Abstract. A new hygroscopic tandem differential mobility analyzer (H-TDMA) has been constructed at Lund University within the frameworks of the EU FP6 Infrastructure Project EUSAAR (http://www.eusaar.org/). The aim of this coordinated H-TDMA development is to design and evaluate a new generation of H-TDMAs that are capable of conducting long term measurements of the hygroscopic growth and state of mixing of sub-micrometer atmospheric aerosol particles at the EUSAAR aerosol super-sites across Europe. The H-TDMA constructed for this project has been validated with respect to hygroscopic growth factor, stability of relative humidity (RH), temperature stability and its ability to operate unattended for longer periods of time. When measuring growth factors of ammonium sulphate, the new H-TDMA system was found to measure within a growth factor deviation of ±0.05 compared to previously recorded data by Tang et al. (1994). The long term RH of the system has been found stable at 90.0% with a standard deviation of ±0.23% and an average temperature variability of the second DMA less than ±0.1 K. Daily automated ammonium sulphate measurements have validated the ambient measurements. The instrument is operated at the EMEP/EUSAAR background station Vavihill in the southern part of Sweden.

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4

Yun, Changho, and Yong-Kon Lim. "GSR-TDMA: A Geometric Spatial Reuse-Time Division Multiple Access MAC Protocol for Multihop Underwater Acoustic Sensor Networks." Journal of Sensors 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/6024610.

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The nonnegligible propagation delay of acoustic signals causes spatiotemporal uncertainty that occasionally enables simultaneous, collision-free packet transmission among underwater nodes (UNs). These transmissions can be handled by efficiently managing the channel access of the UNs in the data-link layer. To this end, Geometric Spatial Reuse-TDMA (GSR-TDMA), a new TDMA-based MAC protocol, is designed for use in centralized, multihop underwater acoustic sensor networks (UASNs), and in this case all UNs are periodically scheduled after determining a geometric map according to the information on their location. The scheduling strategy increases the number of UNs that send packets coincidentally via two subscheduling configurations (i.e., interhop and intrahop scheduling). Extensive simulations are used to investigate the reception success rate (RSR) and the multihop delay (MHD) of GSR-TDMA, and the results are compared to those of previous approaches, including C-MAC and HSR-TDMA. GSR-TDMA outperforms C-MAC; the RSR of GSR-TDMA is 15% higher than that of C-MAC, and the MHD of GSR-TDMA is 30% lower than that of C-MAC at the most. In addition, GSR-TDMA provides even better performance improvements over HSR-TDMA; the RSR of GSR-TDMA is 50% higher than that of HSR-TDMA, and the MHD of GSR-TDMA is an order of102lower than that of HSR-TDMA at the most.

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5

Massling, A., N. Niedermaier, T. Hennig, E. Fors, E. Swietlicki, M. Ehn, K. Hämeri, et al. "Results and recommendations from an intercomparison of six Hygroscopicity-TDMA systems." Atmospheric Measurement Techniques Discussions 3, no. 1 (February 15, 2010): 637–74. http://dx.doi.org/10.5194/amtd-3-637-2010.

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Abstract. The performance of six custom-built Hygrocopicity-Tandem Differential Mobility Analyzers (H-TDMA) systems was investigated in the frame of an international calibration and intercomparison workshop held in Leipzig, February 2006. The goal of the workshop was to harmonize H-TDMA measurements and develop recommendations for atmospheric measurements and their data evaluation. The H-TDMA systems were compared in terms of the sizing of dry particles, relative humidity (RH) uncertainty and consistency in determination of number fractions of different hygroscopic particle groups. The experiments were performed in an air-conditioned laboratory using ammonium sulfate particles or an external mixture of ammonium sulfate and soot particles. The sizing of dry particles of the six H-TDMA systems was within 0.2 to 4.2% of the selected particle diameter depending on investigated size and individual system. With regard to RH uncertainties, the H-TDMA systems showed deviations up to 4.5% RH from the set point at RH=90% investigating the hygroscopic growth of ammonium sulfate particles and comparing the results with theory. The evaluation of number fractions investigating an externally mixed aerosol delivered differences up to +/−8% in calculated number fraction for one and the same aerosol type. We analysed the datasets of the different H-TDMAs with one fitting routine to investigate differences caused by the different data evaluation procedures. The results showed that the differences were reduced from +12/−13% to +8/−6%. We can conclude here that a common data evaluation procedure to determine the number fraction of externally mixed aerosols will improve the comparability of H-TDMA measurements. We finally recommend, to ensure a good calibration of all flow, temperature and RH sensors in the systems. It is most important to thermally insulate the RH control unit and the second DMA and to monitor those temperatures as accurately as 0.2 °C. For a correct determination of external mixtures, it is necessary to take into account size-dependent losses due to the diffusion in the pluming between the DMAs and in the aerosol humidification unit.

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6

Asker, Dalal, Teruhiko Beppu, and Kenji Ueda. "Sphingomonas jaspsi sp. nov., a novel carotenoid-producing bacterium isolated from Misasa, Tottori, Japan." International Journal of Systematic and Evolutionary Microbiology 57, no. 7 (July 1, 2007): 1435–41. http://dx.doi.org/10.1099/ijs.0.64828-0.

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A yellow-pigmented, Gram-negative, motile, strictly aerobic, pleomorphic bacterium (strain TDMA-16T) was isolated from a freshwater sample collected at Misasa (Tottori, Japan). Strain TDMA-16T was slightly tolerant to gamma-ray irradiation and produced carotenoids, including zeaxanthin, nostoxanthin and an unknown carotenoid, effectively [1.7 mg (g dry cells)−1]. The DNA G+C content of strain TDMA-16T was 63.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences placed strain TDMA-16T in a distinct lineage in the family Sphingomonadaceae; sequence data showed that strain TDMA-16T was most closely related to Sphingomonas mali IFO 15500T (95.1 %), Sphingomonas aquatilis JSS7T (95.0 %), Sphingomonas pruni IFO 15498T (94.9 %), Sphingomonas melonis DSM 14444T (94.9 %) and Sphingomonas asaccharolytica IFO 15499T (94.5 %). The major fatty acids of strain TDMA-16T were C17 : 1 ω6c (34.5 %) and C18 : 1 ω7c (29.3 %). The presence of Q-10 as the main ubiquinone, the Sphingomonadaceae-specific sphingoglycolipid in the polar lipid profile and 2-hydroxy fatty acids, plus the absence of 3-hydroxy fatty acids, supported identification of this strain as a member of the genus Sphingomonas sensu stricto. Phylogenetic distinctiveness and unique phenotypic characteristics differentiated strain TDMA-16T from closely related Sphingomonas species. The results of polyphasic taxonomic analyses suggest that strain TDMA-16T represents a novel Sphingomonas species, for which the name Sphingomonas jaspsi sp. nov. is proposed. The type strain is strain TDMA-16T (=NBRC 102120T=DSM 18422T=CCUG 53607T).

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7

Aji, Rizal Fathoni, Heru Suhartanto, and Setiadi Yazid. "A Sense-based Registration Process for TDMA in IEEE 802.11 Network." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 1 (February 1, 2018): 355. http://dx.doi.org/10.11591/ijece.v8i1.pp355-359.

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TDMA implementation offer better fairness and throughput in IEEE 802.11. To implement TDMA, new registration process is needed, because current registration mechanism can disrupt TDMA process. This paper proposes a sense-based TDMA registration process using service slot and random timer. Simulation result shows, by using our mechanism, we can reduce the number of unused timeslot, and for 10 new nodes, each node only need 7 ms to complete the registration process.

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8

Nguyen, VanDung, Tran Anh Khoa, Thant Zin Oo, Nguyen H. Tran, Choong Seon Hong, and Eui-Nam Huh. "Time Slot Utilization for Efficient Multi-Channel MAC Protocol in VANETs." Sensors 18, no. 9 (September 10, 2018): 3028. http://dx.doi.org/10.3390/s18093028.

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In vehicular ad hoc networks (VANETs), many schemes for a multi-channel media access control (MAC) protocol have been proposed to adapt to dynamically changing vehicle traffic conditions and deliver both safety and non-safety packets. One such scheme is to employ both time-division multiple access (TDMA) and carrier-sense multiple access (CSMA) schemes (called a hybrid TDMA/CSMA scheme) in the control channel (CCH) interval. The scheme can adjust the length of the TDMA period depending on traffic conditions. In this paper, we propose a modified packet transmitted in the TDMA period to reduce transmission overhead under a hybrid TDMA/CSMA multi-channel MAC protocol. Simulation results show that a MAC protocol with a modified packet supports an efficient packet delivery ratio of control packets in the CCH. In addition, we analyze the hybrid TDMA/CSMA multi-channel MAC protocol with the modified packet under saturated throughput conditions on the service channels (SCHs). The analysis results show that the number of neighbors has little effect on the establishment of the number of time slots in TDMA periods and on SCHs under saturated throughput conditions.

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9

Asker, Dalal, Tarek S. Awad, Lynne McLandsborough, Teruhiko Beppu, and Kenji Ueda. "Deinococcus depolymerans sp. nov., a gamma- and UV-radiation-resistant bacterium, isolated from a naturally radioactive site." International Journal of Systematic and Evolutionary Microbiology 61, no. 6 (June 1, 2011): 1448–53. http://dx.doi.org/10.1099/ijs.0.013482-0.

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Four gamma- and UV-radiation-resistant bacterial strains, designated TDMA-24T, TDMA-24-2, TDMA-24-3 and TDMA-24-4, were isolated from a fresh-water sample collected at Misasa, Tottori, Japan. Cells of these strains were Gram-reaction-positive, non-motile, non-spore-forming, rod-shaped and formed red colonies. The genomic DNA G+C contents ranged from 70.5 to 70.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel isolates belong to the genus Deinococcus, the highest sequence similarities being with Deinococcus aquaticus PB314T (98 %) and Deinococcus caeni Ho-08T (97 %). The polar lipid profile of strain TDMA-24T comprised three unidentified phosphoglycolipids, five unidentified glycolipids and seven unidentified polar lipids. MK-8 was the predominant respiratory quinone. Major fatty acids were iso-C15 : 0, C15 : 1ω6c, C15 : 0, C16 : 0 and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c). On the basis of their phylogenetic positions and chemotaxonomic and phenotypic characteristics, the novel isolates represent a novel species of the genus Deinococcus, for which the name Deinococcus depolymerans sp. nov. is proposed. The type strain is TDMA-24T ( = JCM 14369T = NBRC 102115T = CCUG 53609T).

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10

Nofal, Samer. "On the time complexity of achieving optimal throughput in time division multiple access communication networks." AIMS Mathematics 9, no. 5 (2024): 13522–36. http://dx.doi.org/10.3934/math.2024659.

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<abstract><p>The fundamental problem of finding transmission schedules for achieving optimal throughput in time division multiple access (TDMA) communication networks is known to be NP-hard. Let $ \mathcal{N} $ be a scheduled $ k $-time slot TDMA network with $ n $ stations and $ m $ links. We showed that an optimal link schedule for $ \mathcal{N} $ can be computed recursively with a recursion tree of logarithmic depth $ \mathcal{O}(\ln m) $ in expectation. Additionally, we showed that optimal link schedules for those TDMA networks, with recursion trees of depth meeting the expectation, can be found in time $ \mathcal{O}(m^{2+\ln k}) $. Likewise, we discuss analogous results for computing optimal station schedules of TDMA networks.</p></abstract>

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Sivakumar, V., and D. Rekha. "Underwater Acoustic Sensor Node Scheduling using an Evolutionary Memetic Algorithm." Journal of Telecommunications and Information Technology 1 (March 28, 2018): 88–94. http://dx.doi.org/10.26636/jtit.2018.116217.

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Underwater Acoustic Sensor Networks (UWASNs) play an important role in monitoring the aqueous environment which has created a lot of interest for researchers and scientists. Utilization of underwater acoustic sensor node (UASN) scheduling for transmission remains, due to the limited acoustic bandwidth available, a challenge in such an environment. One of the methods to overcome this problem is to efficiently schedule UASN data using time division multiple access (TDMA) protocols the parallel transmissions, simultaneously avoiding interference. The paper shows how to optimize the utilization of acoustic sensor node bandwidth by maximizing the possible node transmissions in the TDMA frame and also by minimizing the node's turnaround wait time for its subsequent transmissions by using an evolutionary memetic algorithm (MA). The simulation of MA-TDMA proves that as the size of the network increases, every node in UWASN transmits with an average minimal turnaround transmission time. It also proves that as the TDMA cycle repeats, the overall network throughput gets maximized by increasing the possible node transmissions in the MA-TDMA frame.

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12

Zhang, Yi Bo, and Yan Qin Li. "Design and Application of the Efficient Time-Division Multiple Address Protocol for Hybrid Server." Applied Mechanics and Materials 380-384 (August 2013): 2083–86. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.2083.

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The protocol of the hybrid server was designed based on the Internet of things for the realization of the intelligent management with the different equipments under the Internet of things. The Internet of things had large number of nodes, and the net topology was easy to change, it also had high requirements for the reliability. According to the properties of these properties, an efficient time-division multiple address protocol that was called E-TDMA protocol was proposed based on the improvement of the time division multiple address protocol. A power management system was designed based on the Internet of things, and the Internet of things was applied in the intelligent power management system, the indexes of the E-TDMA protocol based on the Internet of things such as throughput capacity, network stability were tested with the simulation. Test result shows that the number of the data packets in the buffer cache is much less than the traditional TDMA protocol and the dynamical TDMA protocol. It is because that the E-TDMA can make all the units can send data in the same time through CDMS coding. The result shows that the proposed E-TDMA protocol has efficient performance of accessing to the information channel and stability of network transmission in the application of the power management system.

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Jabbair, B., and D. McDysan. "Performance of demand assignment TDMA and multicarrier TDMA satellite networks." IEEE Journal on Selected Areas in Communications 10, no. 2 (1992): 478–86. http://dx.doi.org/10.1109/49.126998.

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Yan, Zhongjiang, Qianqian Li, Bo Li, and Mao Yang. "A Link Distance Division Based Time Division Multiple Access Protocol for Directional Aeronautical Relay Networks." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 1 (February 2020): 147–54. http://dx.doi.org/10.1051/jnwpu/20203810147.

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In directional aeronautical relay networks, the airplane relay explores the advantages of the directional antenna, in terms of long transmission distance, low transmission power, small interference range and so on, to help the ground nodes transmitting data. However, data transmission delay extension problem occurs when the distance of the transmission link extends, where the wireless signal transmission time approximates the data transmission time such that the wireless signal transmission time cannot be omitted. To address the data transmission delay extension problem, a link distance division based time division multiple access protocol, LDD-TDMA, is proposed in this paper. Different from the traditional TDMA protocol, where the time slots are equal and are determined by the longest transmission link, the length of the time slots are different and are determined by different transmission links. Furthermore, the concept of communication coverage ring is proposed where the nodes located in the same ring communicate with the relay utilizing the same time slot length. The relationships between the number of rings, the ring radius and the transmission range of the LDD-TDMA are modelled and derived as a closed formula, where the ring radius are optimized such that the gain is maximized. Simulation results show that LDD-TDMA outperforms TDMA by 13.37% when the transmission range is 200 km and the ring number is 4.

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LIM, ALVIN, and KUI MOK. "PERFORMANCE EVALUATION OF ADAPTIVE MEDIA ACCESS CONTROL PROTOCOLS FOR PERVASIVE WIRELESS NETWORKS." Journal of Interconnection Networks 03, no. 03n04 (September 2002): 253–72. http://dx.doi.org/10.1142/s0219265902000665.

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As pervasive and high-density wireless networks become increasingly common, it is critical to address the problems of intermittent disconnection, high error rate and collision that cause degradation in the performance of wireless media access control protocols, such as slotted ALOHA Time Division Multiple Access (slotted ALOHA/TDMA) and Direct Sequence Code Division Multiple Access (DS/CDMA). We propose adaptive techniques for improving performance of media access protocols through awareness of the mobile communication environment. These techniques involve detection of intermittent disconnection, high error rates, and collisions. Upon detection and notification of these conditions by snooping devices, the media access control layer adapts its operation and synchronization accordingly to reduce delay and loss of bandwidth. Results from our simulation studies show that adaptive TDMA improves performance by as much as 12 times over basic TDMA and adaptive CDMA improves by as much as 4 times over basic CDMA in wireless network with high density cells. Overall, adaptive CDMA still performs better than adaptive TDMA by about 4 times.

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Vaattovaara, P., M. Räsänen, T. Kühn, J. Joutsensaari, and A. Laaksonen. "A method for detecting the presence of organic fraction in nucleation mode sized particles." Atmospheric Chemistry and Physics Discussions 5, no. 3 (June 1, 2005): 3595–620. http://dx.doi.org/10.5194/acpd-5-3595-2005.

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Abstract. New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm) and the lower end of Aitken mode particles (d≤50 nm) is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer) method to shed light on the presence of organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

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Vaattovaara, P., M. Räsänen, T. Kühn, J. Joutsensaari, and A. Laaksonen. "A method for detecting the presence of organic fraction in nucleation mode sized particles." Atmospheric Chemistry and Physics 5, no. 12 (December 14, 2005): 3277–87. http://dx.doi.org/10.5194/acp-5-3277-2005.

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Abstract. New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm) and the lower end of Aitken mode particles (d≤50 nm) is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer) method to shed light on the presence of an organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10 nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various oxidized organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

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Morozs, Nils, Paul Mitchell, and Yuriy V. Zakharov. "TDA-MAC: TDMA Without Clock Synchronization in Underwater Acoustic Networks." IEEE Access 6 (2018): 1091–108. http://dx.doi.org/10.1109/access.2017.2777899.

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Wang, Jui Teng. "Throughput analysis for interference limited TDMA and TDMA/CDMA wirelessad hocnetworks." International Journal of Communication Systems 22, no. 3 (March 2009): 365–72. http://dx.doi.org/10.1002/dac.967.

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XU, WANG, and ZI SHU HE. "A Weighed Least Square TDOA Location Algorithm for TDMA Multi-target." International Journal of Wireless and Microwave Technologies 1, no. 2 (April 15, 2011): 16–25. http://dx.doi.org/10.5815/ijwmt.2011.02.03.

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Kazama, Hiroshi, Takatoshi Sugiyama, and Hideki Fukuda. "Experiments on satellite TDMA system for multimedia communications." Electronics and Communications in Japan (Part I: Communications) 84, no. 10 (April 18, 2001): 55–65. http://dx.doi.org/10.1002/ecja.1047.

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AbstractAs a new form of communications, computer networks represented by the Internet have become widespread. In these networks, multimedia information such as static and dynamic images, audio, data file, and so on are handled. In such multimedia communications, the access circuits of the users are low‐speed ones while the return links to the users are large‐capacity, high‐speed circuits and, therefore, the configuration has an asymmetric bidirectional form. In this paper, as a highly efficient method of transmission of asymmetric bidirectional multimedia communications with different speeds, which can be adopted only to satellite systems, the TDMA signals of variable transmission speeds are used in the return links of multiple connected transmitting stations. The multiplexed SSMA signals are superposed on TDMA signals of the low‐speed forward links. Such a multimedia satellite TDMA communication system is proposed and a fabricated prototype is used in the satellite connections of the NTT Yokosuka and Musashino Research Centers. In this prototype, the actual TDMA capacity is 42.24 Mbits/s while 20 circuits of 32 kbits/s are accommodated in the SSMA signal. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(10): 55–65, 2001

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Hu, Jinbin, Wenjun Lyu, Shaohua Zhong, and Jiawei Huang. "Motion Prediction Based TDMA Protocol in VANETs." Electronics 9, no. 11 (October 29, 2020): 1792. http://dx.doi.org/10.3390/electronics9111792.

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In Vehicular Ad Hoc Networks (VANETs), the high mobility of vehicle nodes makes the network topology change frequently, reducing the forwarding efficiency of MAC protocol. In the existing enhanced TDMA-based MAC protocol, the farthest node in the current transmission range is chosen as the forwarding node to accelerate the multi-hop transmission. However, we use probabilistic model to show that there potentially exist better forwarding nodes, which could effectively improve transmission efficiency. Therefore, we propose a motion-prediction based TDMA protocol, which predicts the network topology in the next frame to select the better forwarding node. The test results of highway and urban scenarios show that the motion-prediction based TDMA protocol effectively reduces the number of hops in multi-hop transmission and decreases the broadcast delay by 50% to cover the whole network.

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Jia, Gu, Yu Wen Wang, Fan Ji Meng, Guo Hua Ye, and Guo Lin Wang. "An Adaptive TDMA Slot Assignment Algorithm for Scalable Wireless Mesh Networks." Applied Mechanics and Materials 392 (September 2013): 872–75. http://dx.doi.org/10.4028/www.scientific.net/amm.392.872.

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The media access control (MAC) protocol based on fixed slot allocation has low throughput and high delay in high load wireless mesh network. In order to improve the performance of wireless mesh network, we propose a scalable adaptive time division multiple access (TDMA) slot allocation algorithm based on the existing fixed TDMA. The algorithm uses the network structure of clustering and builds a more optimized frame structure, cluster head dynamically allocates time slot according to the packet number of the cluster member sent and the priority level, at the same time taking into account the situation of nodes joining and leaving to improve the scalability of the network The simulation results on OPNET network simulation platform show that the algorithm is superior to fixed TDMA algorithm in both throughput and delay.

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Nosheen, Irum, Shoab A. Khan, and Umar Ali. "A Cross-Layer Design for a Multihop, Self-Healing, and Self-Forming Tactical Network." Wireless Communications and Mobile Computing 2019 (April 9, 2019): 1–16. http://dx.doi.org/10.1155/2019/1523906.

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In mission and time critical applications, bandwidth and delay optimizations are the key goals of communication systems. This paper presents a cross-layer framework design that reduces the call setup time, provides collision-free communication, and reuses the empty slots of Time Division Multiple Access (TDMA) protocol which otherwise causes low throughput and large delay. As number of communicating nodes in tactical networks is small as compared to commercial mobile ad hoc networks (MANETs), classical TDMA will yield huge number of empty slots and any Carrier Sense Multiple Access/Collision Detection (CSMA/CD) technique may cause more delay in some critical scenarios. Proposed methodology gives a Cross-Layer Architecture for Network (NET) Layer and Medium Access Control (MAC) Layer. Our design provides bandwidth efficient, collision-free communication to Software-Defined Radios (SDRs) in self-forming and self-healing tactical networks with low call setup time and multihop routing. For this purpose TDMA as MAC layer protocol and Ad Hoc On Demand Distance Vector (AODV) as Network Layer Routing Protocol are used. Our slot allocation (SA) algorithm, Cross-Layer TDMA (CL-TDMA), consists of control phase where AODV control packets are exchanged and data transfer phase where transmission of data and voice occurs. All active radios in vicinity gather information about communicating nodes based on the exchange of control packets by SDRs. Our algorithm then uses this information to help all active SDRs find slot(s) that will be used for collision-free transmission. A number of experiments are performed to establish improved performance of the proposed technique compared to other established techniques and protocols.

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Sekhar, Ravi, Haider Rasheed Abdulshaheed, Harshavardhan Reddy Penubadi, J. F. Tawfeq, Azmi Shawkat Abdulbaq, A. D. Radhi, Pritesh Shah, et al. "Sustainable optimizing WMN performance through meta-heuristic TDMA link scheduling and routing." Heritage and Sustainable Development 6, no. 1 (March 8, 2024): 111–26. http://dx.doi.org/10.37868/hsd.v6i1.389.

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Wireless mesh networks (WMNs) have become a popular solution for expanding internet service and communication in both urban and rural areas. However, the performance of WMNs depends on generating optimized time-division multiple access (TDMA) schedules, which distribute time into a list of slots called superframes. This study proposes novel meta-heuristic algorithms to generate TDMA link schedules in WMNs using two different interference/constraint models: multi-transmit-receive (MTR) and full-duplex (FD). The objectives of this study are to optimize the TDMA frame for packet transmission, satisfy the constraints, and minimize the end-to-end delay. The significant contributions of this study are: (1) proposing effective and efficient heuristic solutions to solve the NP-complete problem of generating optimal TDMA link schedules in WMNs; (2) investigating the new FD interference model to improve the network capacity above the physical layer. To achieve these objectives and contributions, the study uses two popular meta-heuristics, the artificial bee colony (ABC) and/or genetic algorithm (GA), to solve the known NP-complete problems of joint scheduling, power control, and rate control. The results of this study show that the proposed algorithms can generate optimized TDMA link schedules for both MTR and FD models. The joint routing and scheduling approach further minimizes end-to-end delay while maintaining the schedule's minimum length and/or maximum capacity. The proposed solution outperforms the existing solutions in terms of the number of active links, end-to-end delay, and network capacity. The research aims to improve the efficiency and effectiveness of WMNs in most applications that require high throughput and fast response time.

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Cao, Shuo, Honglei Qin, Li Cong, and Yingtao Huang. "TDMA Datalink Cooperative Navigation Algorithm Based on INS/JTIDS/BA." Electronics 10, no. 7 (March 25, 2021): 782. http://dx.doi.org/10.3390/electronics10070782.

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Position information is very important tactical information in large-scale joint military operations. Positioning with datalink time of arrival (TOA) measurements is a primary choice when a global navigation satellite system (GNSS) is not available, datalink members are randomly distributed, only estimates with measurements between navigation sources and positioning users may lead to a unsatisfactory accuracy, and positioning geometry of altitude is poor. A time division multiple address (TDMA) datalink cooperative navigation algorithm based on INS/JTIDS/BA is presented in this paper. The proposed algorithm is used to revise the errors of the inertial navigation system (INS), clock bias is calibrated via round-trip timing (RTT), and altitude is located with height filter. The TDMA datalink cooperative navigation algorithm estimate errors are stated with general navigation measurements, cooperative navigation measurements, and predicted states. Weighted horizontal geometric dilution of precision (WHDOP) of the proposed algorithm and the effect of the cooperative measurements on positioning accuracy is analyzed in theory. We simulate a joint tactical information distribution system (JTIDS) network with multiple members to evaluate the performance of the proposed algorithm. The simulation results show that compared to an extended Kalman filter (EKF) that processes TOA measurements sequentially and a TDMA datalink navigation algorithm without cooperative measurements, the TDMA datalink cooperative navigation algorithm performs better.

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Lee, Cheol-Woong, Gyu-Min Lee, and Byeong-Hee Roh. "Adaptive Strategy to Change Firing Phases of Collided Nodes in Extended-Desync TDMA-Based MANETs." Sensors 21, no. 20 (October 12, 2021): 6776. http://dx.doi.org/10.3390/s21206776.

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As a multi-hop extension of the desynchronization-based TDMA (Desync-TDMA), the extended Desync-TDMA (Ext-Desync) with self-adapting property is proposed to overcome the limitations of existing CSMA/CA and dynamic TDMA-based schemes for Mobile Ad-hoc Networks (MANETs). However, existing studies overlooked the potential problem of firing message collisions caused by node movements, leading to the severe degradation of MANET networking performance. In this paper, we derive a mathematical model to evaluate the problem due to collisions of firing messages for moving nodes. With the derived model, we propose a method for a collided node to determine whether it changes its firing phase or not, adaptively in a distributed manner, by considering both the collision situation and the slot utilization. The comparative analysis between the proposed method and existing representative ones is also presented for various networking features. The performances of the proposed method are compared with CSMA/CA as well as other existing Ext-Desync-based schemes. The numerical results show that the proposed method achieved much faster resolution and higher slot utilization in collision situations than other Ext-Desync-based schemes. In addition, we also show that the proposed method outperformed the comparable methods, including CSMA/CA, in terms of packet delivery ratios and end-to-end delays.

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Dobslaw, Felix, Tingting Zhang, and Mikael Gidlund. "Latency Improvement Strategies for Reliability-Aware Scheduling in Industrial Wireless Sensor Networks." International Journal of Distributed Sensor Networks 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/178368.

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We propose novel strategies for end-to-end reliability-aware scheduling in Industrial Wireless Sensor Networks (IWSNs). Because of stringent reliability requirements in industrial applications where missed packets may have disastrous or lethal consequences, all IWSN communication standards are based on Time Division Multiple Access (TDMA), allowing for deterministic channel access on the MAC layer. We therefore extend an existing generic and scalable reliability-aware scheduling approach by the name of SchedEx. SchedEx has proven to quickly produce TDMA schedules that guarantee a user-defined end-to-end reliability levelρ_for all multihop communication in a WSN. Moreover, SchedEx executes orders of magnitude faster than recent algorithms in the literature while producing schedules with competitive latencies. We generalize the original problem formulation from single-channel to multichannel scheduling and propose a scalable integration into the existing SchedEx approach. We further introduce a novel optimal bound that produces TDMA schedules with latencies around 20% shorter than the original SchedEx algorithm. Combining the novel strategies with multiple sinks, multiple channels, and the introduced optimal bound, we could through simulations verify latency improvements by almost an order of magnitude, reducing the TDMA superframe execution times from tens of seconds to seconds only, which allows for a utilization of SchedEx for many time-critical control applications.

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29

Colby, Roger J. "TDMA: its finally here!" International Journal of Satellite Communications 3, no. 1-2 (January 1985): 1–2. http://dx.doi.org/10.1002/sat.4600030102.

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Benjamin, Melvin C., and Winston M. Bogaert. "Comsat's tdma traffic terminal." International Journal of Satellite Communications 3, no. 1-2 (January 1985): 15–25. http://dx.doi.org/10.1002/sat.4600030106.

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Barnett, Jerry, and John F. Phiel. "Intelsat tdma system monitor." International Journal of Satellite Communications 3, no. 1-2 (January 1985): 57–69. http://dx.doi.org/10.1002/sat.4600030110.

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Bernard, A., L. Kerromes, J. Meunier, F. Rancy, C. Bareyt, D. Vautier, A. Beaucent, J. Salomon, and C. Sergent. "The french tdma terminal." International Journal of Satellite Communications 3, no. 1-2 (January 1985): 85–100. http://dx.doi.org/10.1002/sat.4600030113.

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Zhang, Tianjiao, and Qi Zhu. "EVC-TDMA: An enhanced TDMA based cooperative MAC protocol for vehicular networks." Journal of Communications and Networks 22, no. 4 (August 2020): 316–25. http://dx.doi.org/10.1109/jcn.2020.000021.

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Nando, Ferry, A. Permatasari, Lindawati, A. S. Handayani, C. R. Sitompul, and Hani M. Putri. "Transmission Performance Analysis of TDMA Radio and MAC Communication of TDMA Protocol." Journal of Physics: Conference Series 1167 (February 2019): 012015. http://dx.doi.org/10.1088/1742-6596/1167/1/012015.

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Saravanan, M., Rajeev Sukumaran, M. R. Christhuraj, and T. T. Manikandan. "Stochastic Network Calculus Model for Delay Distribution of Time Division Multiple Access and Carrier Sense Multiple Access in Underwater Acoustic Wireless Communication." Revista Gestão Inovação e Tecnologias 11, no. 4 (July 22, 2021): 2885–901. http://dx.doi.org/10.47059/revistageintec.v11i4.2325.

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Underwater Acoustic wireless communication becomes a popular research area for transmitting and receiving data between the communicators in the ocean environment. High accuracy in data communication can be succeeded by proficient modeling of carrier sense multiple access and time division access. For such innovations, the system has to proceed with an appropriate framework to make constant data traffic and limitations on start to finish data traffic delays. There are two major wireless communication multiple access methods that can be utilized in real-time underwater networks. One of the multiple access schemes is TDMA and another one is CSMA/CA. This paper concentrated on the modeling of TDMA and CSMA/CA also proposes the comparison of delay (end-end) of both multiple access protocols. The results using SNC to obtain delay bounds and are associated with simulation. The results show TDMA has a lesser efficiency than CSMA/CA in the acoustic environment.

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Aslam, Aqsa, Pedro M. Santos, Frederico Santos, and Luís Almeida. "Empirical Performance Models of MAC Protocols for Cooperative Platooning Applications." Electronics 8, no. 11 (November 12, 2019): 1334. http://dx.doi.org/10.3390/electronics8111334.

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Vehicular ad-hoc networks (VANET) enable vehicles to exchange information on traffic conditions, dynamic status and localization, to enhance road safety and transportation efficiency. A typical VANET application is platooning, which can take advantage of exchanging information on speed, heading and position to allow shorter inter-vehicle distances without compromising safety. However, the platooning performance depends drastically on the quality of the communication channel, which in turn is highly influenced by the medium access control protocol (MAC). Currently, VANETs use the IEEE 802.11p MAC, which follows a carrier sense multiple access with collision avoidance (CSMA/CA) policy that is prone to collisions and degrades significantly with network load. This has led to recent proposals for a time-division multiple access (TDMA)-based MAC that synchronize vehicles’ beacons to prevent or reduce collisions. In this paper, we take CSMA/CA and two TDMA-based overlay protocols, i.e., deployed over CSMA/CA, namely PLEXE-slotted and RA-TDMAp, and carry out extensive simulations with varying platoon sizes, number of occupied lanes and transmit power to deduce empirical models that provide estimates of average number of collisions per second and average busy time ratio. In particular, we show that these estimates can be obtained from observing the number of radio-frequency (RF) neighbours, i.e., number of distinct sources of the packets received by each vehicle per time unit. These estimates can enhance the online adaptation of distributed applications, particularly platooning control, to varying conditions of the communication channel.

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Carvalho, Fabiano C., and Carlos E. Pereira. "A runtime stability analysis of clock synchronization precision on a time-triggered bus prototype." Sba: Controle & Automação Sociedade Brasileira de Automatica 20, no. 1 (March 2009): 45–52. http://dx.doi.org/10.1590/s0103-17592009000100004.

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This paper provides a runtime stability analysis of the Daisy-Chain clock synchronization algorithm running over CASCA - a time-triggered extension of CAN bus. The main objective is to show with practical results how to achieve global time base of high precision and how this precision is affected by the modification of the TDMA transmission schedule. That contributes by providing some basic guidelines for the task of designing time-triggered, TDMA-based distributed systems for embedded control applications.

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Park, Sihyeong, Mi-Young Kwon, Hoon-Kyu Kim, and Hyungshin Kim. "Execution Model to Reduce the Interference of Shared Memory in ARINC 653 Compliant Multicore RTOS." Applied Sciences 10, no. 7 (April 3, 2020): 2464. http://dx.doi.org/10.3390/app10072464.

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Multicore architecture is applied to contemporary avionics systems to deal with complex tasks. However, multicore architectures can cause interference by contention because the cores share hardware resources. This interference reduces the predictable execution time of safety-critical systems, such as avionics systems. To reduce this interference, methods of separating hardware resources or limiting capacity by core have been proposed. Existing studies have modified kernels to control hardware resources. Additionally, an execution model has been proposed that can reduce interference by adjusting the execution order of tasks without software modification. Avionics systems require several rigorous software verification procedures. Therefore, modifying existing software can be costly and time-consuming. In this work, we propose a method to apply execution models proposed in existing studies without modifying commercial real-time operating systems. We implemented the time-division multiple access (TDMA) and acquisition execution restitution (AER) execution models with pseudo-partition and message queuing on VxWorks 653. Moreover, we propose a multi-TDMA model considering the characteristics of the target hardware. For the interference analysis, we measured the L1 and L2 cache misses and the number of main memory requests. We demonstrated that the interference caused by memory sharing was reduced by at least 60% in the execution model. In particular, multi-TDMA doubled utilization compared to TDMA and also reduced the execution time by 20% compared to the AER model.

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Lu, Jun, and De Zhi An. "TDMA-Based Time Slots Assignment Algorithm." Applied Mechanics and Materials 241-244 (December 2012): 2445–53. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.2445.

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In this paper we studied timeliness of TDMA-based MAC scheduling mechanisms. TDMA-based MAC protocols require sensor nodes to deliver data individually so as to eliminate collisions in shared channel. This scheduling mechanism can assist sensor nodes in managing energy efficiently since data resending that collisions induced has a significant impact on battery life. But during medium access arbitration, the elected central node has to receive other nodes’ state messages one by one before assigning time slots for each node. While in large-scale sensor networks, the waiting time would be a relatively long duration and result in timeliness decrease in time-sensitive environments. We propose a novel time slots assignment algorithm for TDMA-based MAC protocols that allows sensor nodes to deliver state messages simultaneously to central node for medium access arbitration and present an analysis in which these two approaches are compared in respect to timeliness. The algorithm is evaluated through simulation. Simulation results have confirmed the timeliness of our new algorithm.

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Djukic, P., and P. Mohapatra. "Soft-TDMAC: A Software-Based 802.11 Overlay TDMA MAC with Microsecond Synchronization." IEEE Transactions on Mobile Computing 11, no. 3 (March 2012): 478–91. http://dx.doi.org/10.1109/tmc.2011.56.

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Fan, Jing, Jian Bin Xie, Feng Li, and Geng Li. "Adaptive Energy Efficient Cross-Layer TDMA-Based MAC Protocol in Wireless Mesh Sensor Networks." Applied Mechanics and Materials 462-463 (November 2013): 98–103. http://dx.doi.org/10.4028/www.scientific.net/amm.462-463.98.

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Based on TDMA sleep scheduling scheme, by collecting cross-layer routing information and feedback information, according to the detection of routing information and neighbor information, the sleep slot and data transmitting slot are assigned orderly on TDMA based channel by Mesh router. The sending and receiving mutual interference collision is eliminated by slot allocation with collision avoid method. Moreover, path wake up strategy in terms of the nodes hop are introduced which can assign listen frame and wake up slot better. As a result, a TDMA-based energy efficient cross-layer MAC protocol for wireless mesh sensor networks are proposed, and then the performance of the protocol are analysis by simulation. The study results show that based on WMN and WSN, WSN and WMN can be constructed to achieve a full interconnection network named WMSN.TCP-MCA protocol can effectively reduce idle listen time of node which reduce overall energy consumption of the network.

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Chathalingath, Anishchandran, and Arun Manoharan. "Performance Optimization of Tridiagonal Matrix Algorithm [TDMA] on Multicore Architectures." International Journal of Grid and High Performance Computing 11, no. 4 (October 2019): 1–12. http://dx.doi.org/10.4018/ijghpc.2019100101.

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Fast and efficient tridiagonal solvers are highly appreciated in scientific and engineering domain, but challenging optimization task for computer engineers. The state-of-the-art developments in multi-core computing paves the way to meet this challenge to an extent. The technical advances in multi-core computing provide opportunities to exploit lower levels of parallelism and concurrency for inherently sequential algorithms. In this article, the authors present an optimal performance pipelined parallel variant of the conventional Tridiagonal Matrix Algorithm (TDMA), aka the Thomas algorithm, on a multi-core CPU platform. The implementation, analysis and performance comparison of the proposed pipelined parallel TDMA and the conventional version are performed on an Intel SIMD multi-core architecture. The results are compared in terms of elapsed time, speedup, cache miss rate. For a system of ‘n' linear equations where n = 2^36 in presented pipelined parallel TDMA achieves speedup of 1.294X with a parallel efficiency of 43% initially and inclines towards linear speed up as the system grows.

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Schlegel, Robert E., Shalini Srinivasan, Hank Grant, Randa L. Shehab, and Shivakumar Raman. "Clinical Assessment of Electromagnetic Compatibility of Hearing Aids and Digital Wireless Phones." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 42, no. 14 (October 1998): 1023–27. http://dx.doi.org/10.1177/154193129804201404.

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Research studies have shown that digital wireless phones interact with some hearing aids, creating a buzzing noise that may reduce speech intelligibility. Interference signals for three phone technologies were generated at five sound pressure levels (35 dB, 45 dB, 55 dB, 65 dB, and 75 dB) and mixed with speech at 65 dB SPL to test the speech intelligibility of 24 hearing-impaired people. A “No Noise” condition was also tested. Scores for the TDMA-217 Hz phone signal at low speech-to-noise ratios (<10 dB) were significantly lower than those for CDMA and TDMA-50 Hz at the same level. The CDMA and TDMA-50 Hz phone signals had a similar effect on speech intelligibility. Speech intelligibility scores at speech-to-noise ratios of 20 dB and 30 dB were similar to those for the “No Noise” condition. The articulation index represented the best index for predicting the impact of wireless phone interference on speech intelligibility.

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Verma, Pawan Kumar, Rajesh Verma, Arun Prakash, and Rajeev Tripathi. "Throughput-Delay Evaluation of a Hybrid-MAC Protocol for M2M Communications." International Journal of Mobile Computing and Multimedia Communications 7, no. 1 (January 2016): 41–60. http://dx.doi.org/10.4018/ijmcmc.2016010104.

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This paper proposes a robust hybrid-MAC protocol for direct communication among M2M devices with gateway coordination. The proposed protocol combines the benefits of both contention-based and reservation-based MAC schemes. The authors assume that the contention and reservation portion of M2M devices is a frame structure, which is comprised of two sections: Contention Interval (CI) and Transmission Interval (TI). The CI is based on p-persistent CSMA mechanism, which allows M2M devices to compete for the transmission slots with equal priorities. After contention, only those devices, which have won time-slots, are allowed to transmit data packets during TI. In the authors' proposed MAC scheme, the TI is basically a TDMA frame and each M2M device is 802.11 enabled. Each M2M transmitter device and its corresponding one-hop distant receiver communicate using IEEE 802.11 DCF protocol within each TDMA slot to overcome the limitations of TDMA mechanism. The simulation results demonstrate the effectiveness of the proposed hybrid-MAC protocol.

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Dong, Luo Bing, Ke Chu Yi, Zhi Qiang Li, and Pei Yi Shen. "Analysis on Cooperative GBN-ARQ Performance in TDMA Single Source and Single Relay Network." Key Engineering Materials 474-476 (April 2011): 1966–73. http://dx.doi.org/10.4028/www.scientific.net/kem.474-476.1966.

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This paper proposes a new cooperative GBN-ARQ（Go-Back-N Cooperative Automatic Repeat Request: GBN-CARQ）algorithm which is suitable for the single source and single relay wireless communication system based on TDMA, establishing the queuing model of single source and single relay wireless communication system based on TDMA and providing the expressions of its throughput and delay performance. By comparing with GBN-ARQ algorithm and normal cooperative ARQ（Cooperative ARQ：CARQ）algorithm, it is shown that GBN-CARQ algorithm has better average throughput performance.

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Sugihara, Makoto. "Dynamic Slot Multiplexing Under Operating Modes for TDMA-Based Real-Time Networking Systems." Electronics 9, no. 2 (January 29, 2020): 224. http://dx.doi.org/10.3390/electronics9020224.

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The Time Division Multiple Access (TDMA) scheme has been proposed as the one which assures real-time messaging in a networking system. In the TDMA scheme, a networking system operates based on time slots which are defined as discrete time units. Some messages are periodically and exclusively assigned to their own time slots and are assured to be sent between network nodes by their own deadline. In this paper, we note that an operating situation of a system determines what functions of the system run. More concretely, an operating situation determines what data the system requires and how frequently it requires them. We propose to introduce operating modes, each of which reflects its own operating situation, to the TDMA scheme. An operating mode is specified by a set of communication signals which are active under the operating mode. We propose a dynamic slot multiplexing (DSM) technique which switches operating modes and assignments of communication signals to time slots adaptively with operating situations. System designers are to schedule all messages of communication signals for every operating mode so that the messages are sent by their own deadline. Compared with a single-mode TDMA system, in which a single message schedule is determined for all communication signals, our approach optimally determines a message schedule for each operating mode so that it can avoid wasting networking resources. Our experiment shows that DSM technique achieves about 21%-37% lower operating frequency than static slot multiplexing one.

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Taylor, N. F., D. R. Collins, C. W. Spencer, D. H. Lowenthal, B. Zielinska, V. Samburova, and N. Kumar. "Measurement of ambient aerosol hydration state at Great Smoky Mountains National Park in the Southeastern United States." Atmospheric Chemistry and Physics Discussions 11, no. 8 (August 4, 2011): 21877–933. http://dx.doi.org/10.5194/acpd-11-21877-2011.

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Abstract. We present results from two field deployments of a unique tandem differential mobility analyzer (TDMA) configuration with two primary capabilities: identifying alternative stable or meta-stable ambient aerosol hydration states associated with hysteresis in aerosol hydration behavior and determining the actual Ambient hydration State (AS-TDMA). This data set is the first to fully classify the ambient hydration state of aerosols despite recognition that hydration state significantly impacts the roles of aerosols in climate, visibility and heterogeneous chemistry. The AS-TDMA was installed at a site in eastern Tennessee on the border of Great Smoky Mountains National Park for projects during the summer of 2006 and winter of 2007–2008. During the summer, 12 % of the aerosols sampled in continuous AS-TDMA measurements were found to posses two possible hydration states under ambient conditions. In every case, the more hydrated of the possible states was occupied. The remaining 88 % did not posses multiple possible states. In continuous measurements during the winter, 49 % of the aerosols sampled possessed two possible ambient hydration states; the remainder possessed only one. Of those aerosols with multiple possible ambient hydration states, 65 % occupied the more hydrated state; 35 % occupied the less hydrated state. This seasonal contrast is supported by differences in the fine particulate (PM2.5) composition and ambient RH as measured during the two study periods. In addition to seasonal summaries, this work includes case studies depicting the variation of hydration state with changing atmospheric conditions.

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Taylor, N. F., D. R. Collins, C. W. Spencer, D. H. Lowenthal, B. Zielinska, V. Samburova, and N. Kumar. "Measurement of ambient aerosol hydration state at Great Smoky Mountains National Park in the southeastern United States." Atmospheric Chemistry and Physics 11, no. 23 (December 7, 2011): 12085–107. http://dx.doi.org/10.5194/acp-11-12085-2011.

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Abstract. We present results from two field deployments of a unique tandem differential mobility analyzer (TDMA) configuration with two primary capabilities: identifying alternative stable or meta-stable ambient aerosol hydration states associated with hysteresis in aerosol hydration behavior and determining the actual Ambient hydration State (AS-TDMA). This data set is the first to fully classify the ambient hydration state of aerosols despite recognition that hydration state significantly impacts the roles of aerosols in climate, visibility and heterogeneous chemistry. The AS-TDMA was installed at a site in eastern Tennessee on the border of Great Smoky Mountains National Park for projects during the summer of 2006 and winter of 2007–2008. During the summer, 12% of the aerosols sampled in continuous AS-TDMA measurements were found to posses two possible hydration states under ambient conditions. In every case, the more hydrated of the possible states was occupied. The remaining 88% did not posses multiple possible states. In continuous measurements during the winter, 49% of the aerosols sampled possessed two possible ambient hydration states; the remainder possessed only one. Of those aerosols with multiple possible ambient hydration states, 65% occupied the more hydrated state; 35% occupied the less hydrated state. This seasonal contrast is supported by differences in the fine particulate (PM2.5) composition and ambient RH as measured during the two study periods. In addition to seasonal summaries, this work includes case studies depicting the variation of hydration state with changing atmospheric conditions.

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Nugraha, I. Gde Dharma, Edwiansyah Zaky Ashadi, and Ardiansyah Musa Efendi. "Performance Evaluation of Collision Avoidance for Multi-node LoRa Networks based on TDMA and CSMA Algorithm." Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications 15, no. 1 (March 29, 2024): 53–74. http://dx.doi.org/10.58346/jowua.2024.i1.005.

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LoRa can be used as the communication technology for the intelligent monitoring system. However, LoRa is usually used for outdoor communication. The usage of LoRa as indoor communication has many challenges. One of the challenges is that collision happens when using standard LoRa devices with only one channel. The algorithms based on TDMA (Time-division Multiple Access) and CSMA (Carrier-sense Multiple Access) protocols can be used to address this challenge. These two algorithms can be modified by applying the device that is the center of the network (gateway) as a central control and the data transmitter (sensor node) as a passive device. The test was conducted on the Intelligent Laboratory Monitoring System to evaluate this design on a multi-node LoRa network. RSSI testing proves that the distance and building interference affect the signal strength or RSSI of sensor nodes, so the average RSSI value is -73.75 with an RSSI threshold of value -106. The gateway successfully collected each sensor node data with an average success of about 64.953%. The experiment results show the success rate of the CSMA-based algorithm is 10% versus 100% in TDMA-based algorithm; the delay is 4125 ms for CSMA-based and 428.3 ms for TDMA-based. This result means that the CSMA-based algorithm is more complex, takes more time to process the data than the TDMA-based algorithm, has a low success rate, and is more prone to collisions.

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ZHANG, X., J. HONG, L. ZHANG, X. SHAN, and V. O. K. LI. "CP-TDMA: Coloring- and Probability-Based TDMA Scheduling for Wireless Ad Hoc Networks." IEICE Transactions on Communications E91-B, no. 1 (January 1, 2008): 322–26. http://dx.doi.org/10.1093/ietcom/e91-b.1.322.

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Journal articles on the topic 'TDMA'

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