Future Mobile Telecommunication Systems Research Articles

Numerically Optimized Fourier Transform-Based Beamforming Accelerated by Neural Networks

Conventional beamforming methods for reconfigurable reflector antennas assume full control over the amplitude and phase of the reflected field. Here, we develop a novel beamforming methodology for reflecting Programmable Metasurfaces (PMS) with capacitive memory. Although utilizing such fully reactive PMS simplifies antenna design and reduces energy consumption, the PMS reflection magnitude is unity and thus a global optimization of the reflection phases over the PMS unit cells is required in each beamforming scenario. We propose an implementation of such an optimization method rooted in the traditional Fourier transform-based beamforming and evaluate its performance. Additionally, we show that a pair of trained feed-forward neural networks (FFNN) with one input, one hidden, and one output layer can replace time-consuming global optimizations in the case of a PMS comprising 3×10 unit cells. We train the FFNNs on a dataset obtained for typical single- and dual-beam beamforming scenarios. After training, the FFNNs perform requested beamforming tasks within a fraction of second and with about the same accuracy as the original optimization algorithm. The proposed methodology may find applications in future mobile telecommunication systems that require real-time beamforming on low-end hardware. The same beamforming methodology can be also employed in short-range wireless power transfer systems.

Spectrum Requirements Estimation for the Future IMT Systems: Current Work and Way Forward

In order to satisfy the spectrum requirements of the future international mobile telecommunication (IMT) systems, to realize scientific allocation and usage of spectrum resources and to avoid spectrum waste brought by allocation in advanced, there is a need to make a reasonable estimation for the spectrum demands of future IMT systems. The estimation results can also provide guidelines for the subsequent spectrum planning and assignment work. This paper gives a description of study progress of related spectrum estimation for future IMT systems. From the analysis of current work and practical situation, the key factors in the estimation methodology are summarized to provide a reference for the following work.

A high-temperature superconducting filter for future mobile telecommunication systems

This paper presents a narrow-band high-temperature superconducting bandpass filter on a sapphire substrate applicable to future mobile communications systems. The design and simulation of a ten-pole quasi-elliptic function filter implemented using a cascaded quadruplet trisection coupling topology is discussed. The filter is designed to have a 10-MHz passband in the Universal Mobile Telecommunications System base-station receive band. The filter substrate was a sapphire wafer measuring 47 mm /spl times/17 mm /spl times/43 mm, which had a double-sided thin-film coating of Yba/sub 2/Cu/sub 3/O/sub 7/. The filter displayed a minimum insertion loss of 0.2 dB in the passband and a return loss better than (-12dB preliminary) over the passband. A high performance out-of-band rejection associated with a quasi-elliptic filter function was also recorded.

Probability criterion paging area planning in future mobile communications systems

Future mobile telecommunications systems are obligated to offer advanced multimedia services to a huge number of users. The burden imposed by the signaling operations supporting these services can severely degrade the system performance and lead to congestion problems in network equipment (switches, databases, gateways, etc.). Paging operations in a mobile cellular network are responsible for a large part of the signaling load and, therefore, the issue of how to efficiently conduct them becomes of critical importance. The key to its solution lies on the application of multiple step paging schemes and on the ‘proper’ planning of paging areas (PAs). In this paper, we devise and solve a version of the PA-planning problem. In particular, we provide a low complexity probabilistic algorithm capable of reducing paging costs. To improve performance, the algorithm uses additional information regarding the locations of last user-network interactions. Numerical results show that significant savings can be achieved compared to a conventional paging scheme.

Base station controller testbed for the future public land mobile telecommunication systems

Base station controller testbed for the future public land mobile telecommunication systems

A reliable and environmentally friendly packaging technology-flip-chip joining using anisotropically conductive adhesive

There is an increasing demand to move the radio base station closer to the antenna for future mobile telecommunication systems. This requires a significant reduction in weight and volume and increased environmental compatibility. This work provides an evaluation of environmental impact and reliability when using anisotropically conductive adhesives (ACA) for flip-chip joining in radio base station applications. Conventional FR-4 substrate has been used to assemble a digital ASIC chip using an anisotropically conductive adhesive and flip-chip technology. The chip has a minimum pitch of 128 /spl mu/m with 7.8 mm in chip 8 and has in total 144 bumps with a bump size of 114/spl times/126 /spl mu/m/sup 2/. Bumping was made using electroless nickel/gold technology. Bonding quality has been characterized by optical and scanning electron microscopy and substrate planarity measurement. The main parameters affecting quality are misalignment and softening of the FR-4 substrate during assembly, leading to high joint resistance. Reliability testing was conducted in the form of a temperature cycling test between -40 and /spl plusmn/125/spl deg/C for 1000 cycles, a 125/spl deg/C aging test for 100 h and a 85/85 humidity test for 500 h. The results show that relatively small resistance changes were observed after the reliability test. The environmental impact evaluation was done in the form of a material content declaration and a life cycle assessment (LCA). By using flip-chip ACA joining technology, the content of environmentally risky materials has been reduced more than ten times, and the use of precious metals has been reduced more than 30 times compared to conventional surface mount technology.

Detection of fraud in mobile telecommunications

Under the CEC’s ACTS’ programme, the collaborative R&D project ASPeCT2 was set up to look at the problems and possible solutions for security in future mobile telecommunications systems to follow on from GSM. The project consortium consisted of Network Operators (Vodafone, Panafon), equipment suppliers (Siemens ATEA, Siemens AG, Giesecke and Devrient) and academic institutions (Royal Holloway, University of London and Katholieke Universiteit Leuven). While the greater part of the project focused on protection of the communication between users mainly related to cryptographic mechanisms and services a substantial section addressed the problems of fraud and abuse of the networks, looking at possible tools for detection and management, but also examining the legal implications.

Applying cryptography within the ASPeCT Project

This article considers the application of cryptographic techniques within the ASPeCT project. ASPeCT is concerned with the provision of certain advanced security features within future mobile telecommunications systems, and we concentrate on two areas of interest within ASPeCT where cryptography is directly being used to provide security solutions: the provision of Trusted Third Party services and the secure billing of value-added information services.

Performance bounds of a multiple-step paging strategy in future universal mobile telecommunication systems

In future mobile telecommunications, due to the huge number of users and the specific functions that support mobility, a significant amount of signaling load will have to be carried by the finite capacity of the radio link. Hence, methods aiming at radio link signaling load reduction are welcome. In this paper we propose and analyze a method that saves paging signaling load by exploiting information related to the terminal location during the most recent interaction between the terminal and the network. The penalty paid is extra processing power and extra paging delays. An analytical model is developed so as to describe the performance versus traffic intensity and mobility conditions. The performance of the proposed paging scheme is investigated, and it is shown that the method operates well even in the worst case, which is the high user mobility conditions. Possible extensions of the method, which exploit information related to the mobility degree of each individual user or information characterizing the mobility conditions in a certain location area, are also proposed.

Evaluation of location area planning scenarios in future mobile telecommunication systems

In third generation mobile telecommunication systems, signalling requirements due to location updating and paging are expected to be remarkable, mainly because of the huge number of mobile subscribers. Location area planning is characterised by the trade-off between the number of location updates and the amount of paging signalling that the network has to deal with. Location area planning should be based on criteria which guarantee that signalling load will be kept under tolerable levels. Various approaches for location area planning in a city environment the worst case environment—are discussed in this paper. The simplest approach is the use of heuristic algorithms for approximating the optimum location area configuration. Then more complex scenarios which are based on geographical criteria (population distribution, highway topology, etc.) are investigated. Finally, user mobility characteristics are taken into account in the most complex scenarios. All scenarios are applied over a simulation model representing a city area, providing us with a very clear view of their performance characteristics.

User profile identification in future mobile telecommunications systems

A UMTS (Universal Mobile Telecommunications System) user profile denotes in which domains and under which conditions a specific service is available to a user. As the research work on UMTS is still in progress, new requirements for the user profile and its management are likely to be set. This article discusses the UMTS user profile identification issues. The authors introduce first the concept of user profile and the UMTS entities related to it. Then, the user profile is described and its management requirements are discussed followed by the description of two scenarios proposed for the user profile identification. Finally, the authors give a comparison of the two scenarios and their concluding remarks. >

Future public land mobile telecommunication systems.

In March 1992, the World Administrative Radio Conference (WARC) of the International Telecommunication Union (ITU), identified global bands 1885-2025 and 2110-2200 MHz for future public land mobile telecommunication systems (FPLMTSs), including 1980-2010 and 2170-2200 MHz for the mobile satellite component. The potential for all FPLMTS radio interfaces to be in the same band provides a strong incentive for trying to maximize the commonality between the satellite and terrestrial component of FPLMTSs. This would simplify multimode mobile equipment and also greatly increase the utility of FPLMTSs for the provision of basic telecommunication needs in underdeveloped regions of the world. Extension of integrated voice, video and data telecommunications to a person rather than a place will have a dramatic effect on everyday life, and on the organizations which currently provide these services. The author outlines some of the international standards work in this area being carried out by the International Radio Consultative Committee/International Telegraph and Telephone Consultative Committee (CCIR/CCITT), in particular that of CCIR TG8/1 (formerly IWP8/13) on FPLMTS.

Future public land mobile telecommunication systems

In March 1992, the World Administrative Radio Conference (WARC) of the International Telecommunication Union (ITU), identified global bands 1885-2025 and 2110-2200 MHz for future public land mobile telecommunication systems (FPLMTSs), including 1980-2010 and 2170-2200 MHz for the mobile satellite component. The potential for all FPLMTS radio interfaces to be in the same band provides a strong incentive for trying to maximize the commonality between the satellite and terrestrial component of FPLMTSs. This would simplify multimode mobile equipment and also greatly increase the utility of FPLMTSs for the provision of basic telecommunication needs in underdeveloped regions of the world. Extension of integrated voice, video and data telecommunications to a person rather than a place will have a dramatic effect on everyday life, and on the organizations which currently provide these services. The author outlines some of the international standards work in this area being carried out by the International Radio Consultative Committee/International Telegraph and Telephone Consultative Committee (CCIR/CCITT), in particular that of CCIR TG8/1 (formerly IWP8/13) on FPLMTS.