TETRA Network Research Articles

Opis tehnologije i standarda TETRA 1 za savremene digitalne tranking sisteme funkcionalnih mobilnih radio-komunikacija

Introduction/purpose: Since the end of 1995, when TETRA MoU promoted the new TETRA Standard within ETSI, tentatively called TETRA 1, it quickly began to be used, almost exclusively, for the construction of Functional UHF digital trunking systems for mobile radio communications. Methods: A description of the relevant issues from the TETRA 1 technology standards and an analysis of existing specifications, with a more detailed presentation of the radio interface. Results: This article highlights the numerous advantages that radio systems based on the TETRA Standard have in relation to the Functional systems of analog trunking of mobile radio communications, and gives an overview of the basic package of Specifications for system implementation based on the TETRA Standard 1. It describes the interfaces used in the system with a special reference to the description of the radio interface, organized by TDMA, and the method of integration of voice and data transmission. The organization and the basic elements of the TETRA network infrastructure are presented as well as those of the final user's equipment, followed by the analysis of possible practical architectures of mobile radio communication networks based on that standard. Conclusion: After the general descriptions of technology, organization, and architecture, the following are presented: the basic concept of the organization of TETRA 1 network use, the general principle of organization of mobile participants' connections and the basic elements of the TETRA network as well as the architecture and topology of the TETRA 1 network construction.

25 godina TETRA tehnologije i standarda za savremene tranking sisteme funkcionalnih digitalnih mobilnih radio-komunikacija

Introduction/purpose: For the construction of functional mobile radio communication systems today, the trunking systems of digital mobile radio communications are almost exclusively used, the main representative of which is the system with the application of TETRA standards. This article describes the beginnings and historical development of this standard, with the activities of ETSI and TETRA MoU in the fight for the availability and harmonization of the frequency spectrum. Methods: A description of relevant issues of the origin and development of the TETRA 1 standard is given as well as the analysis of the characteristic moments of the innovated TETRA 2 standard. Results: This article describes the beginnings and historical development of this standard, with the activities of ETSI and TETRA MoU in the fight for the availability and harmonization of the frequency spectrum. It also systematize the use of the key TETRA systems in the world and shows its share in the world market by sectors, emphasizing the dilemma of its further development at the crossroads after 25 years of existence. Also, a basic overview of the TETRA 1 standard is given while the basic elements and the principle of its application are described. The innovated TETRA 2 standard and the improvements achieved in the way of data transmission are described in more detail; the process of interoperability certification and, in connection with that, the entry of TETRA into the North American market is emphasized. The parameters selected for advanced data transfer according to the TETRA 2-TEDS standard are presented and analyzed, together with an overview of some limitations during practical application. Conclusion: In the conclusion, the current moment of TETRA is analyzed with a focus on its future after 25 years of development, emohasizing a possibility of modernizing and improving the TETRA network of the Ministry of the Interior of Serbia for the needs of the MoD and the Serbian Armed Forces.

LTE Relocation towards Broadband PPDR System in TETRA Network

LTE Relocation towards Broadband PPDR System in TETRA Network

Fuzzy C-Means Clustering-Based Jamming Detection Algorithm at Base Station

Jamming is defined as the act of intentionally directing electromagnetic energy towards a communication system to disrupt or prevent signal transmission. Jamming represents the most serious security threat in the field of wireless cellular networks (WCN), as it can easily put out of order even WCNs that utilize strong high-layer security mechanisms. In this paper, a fuzzy c-means algorithm is proposed for clustering the jammed signals at the base station in WCNs. The jamming detection process itself uses an improved LCR-based Doppler shift estimation algorithm using only inherent information which is available in common receivers without any excessive hardware requirements. The estimation of channel Doppler shift at base station in cellular networks helps base stations in channel estimation, which effectively improves jamming detection performance. The performance of the proposed algorithms in a TETRA network is modeled and compared with conventional methods, and simulation shows acceptable results in a wide range of user terminal velocities.

Utilizing support vector machine and fuzzy C-means algorithms in the base station for jamming detection

This study presents a comparison of two proposed jamming detection algorithms based on fuzzy C-means (FCM) and support vector machine (SVM) algorithms. Since the SVM classification algorithm needs to be trained for a short period of time before implementation, to improve the performance of the FCM-based jamming detection algorithm, a convenient Doppler shift estimation algorithm has been used in order to recognize the information in the channel. The jamming detection process uses only inherent information which is available in common receivers without any excessive hardware requirements. Using SVM- and FCM-based jamming detection algorithms not only improves the performance of jamming detection, but also reduces hardware complexity. The performance of the proposed algorithms in a TETRA network is modeled and simulations show acceptable results over a wide range of user terminal velocities with comparison to conventional methods.

Adaptive control of call acceptance in WCDMA network

Adaptive control of call acceptance in WCDMA network

Macromol. Rapid Commun. 22/2010

Cover: The picture presents the gelation process of a near-ideal polymer network. This network, the Tetra network, is synthesized by cross-end-coupling of mutually reactive tetra-arm precursors. The Tetra network exhibits an extremely homogeneous network structure resulting in high mechanical strength. Further information can be found in the article by T. Sakai,* Y. Akagi, T. Matsunaga, M. Kurakazu, U. I. Chung, and M. Shibayama on page 1954.

Highly Elastic and Deformable Hydrogel Formed from Tetra‐arm Polymers

After decades of efforts by many researchers, we have succeeded in realizing a near-ideal polymer network. This network, the Tetra network, is made by cross-end-coupling of tetra-arm polymer modules. The mechanical energy dissipation was extremely low (tan δ ≈ 10(-4) ). The macroscopic stress-strain relationship of the Tetra network was in good agreement with that of microscopic elastic blobs. The maximum breaking strength was extremely high (≥27 MPa). These results indicate that the Tetra network is closer to an ideal polymer network than any other conventional model networks. Because the Tetra network can be treated as uniformly packed elastic blobs, it should help apply the knowledge of single polymer chains seamlessly to the design of polymer materials and help further develop the theory of rubber elasticity.