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Latest success of open experiments of mmWave systems and networks for the Heterogeneous network in 5G Mobile Communication are reviewed. This is conducted in “wireless-fiber project” funded by the Ministry of Internal Affairs and Communications, Japan and high-speed wireless communication systems above Gb/s has been pursued by the collaborative team in Tokyo Institute of Technology as well as the...
Statistic properties of rainfall in Tokyo are presented in this paper. Average rain duration as a function of rain rate is analyzed for future route switching technique to increase network availability. In case of strong rain (>100 mm/h), minimum and maximum duration were 20 sec. and 335 sec., respectively. It was found that even in the campus within 1 km, rain rate is different at each site and...
Multi-input multi-output (MIMO) transmission with multiple antennas, which performs parallel transmission at the same time and frequency and enhances the channel capacity, has attracted attention. In the case of small mobile terminals, the limitation of spaces for the multiple antennas leads to degrade the improvement of the channel capacity in proportion to the number of the antennas. This paper...
In this paper, an evaluation of the influence of rain and its attenuation on link performance in a Tokyo Institute of Technology (Tokyo Tech) millimeter-wave model mesh network are presented. The unique effects arising due to the highly localized behaviors of strong rainfalls have become clear and are characterized in terms of variogram rather than correlation coefficients. Spatial separation even...
MIMO channel emulation systems have been studied and developed to achieve the evaluation for the MIMO transmission technique of user equipments (UEs) with multiple antennas. The system can generate a multipath with a spatial signature by transmitting signals from multiple probe antennas set around the UE. The resolution of the emulated spatial distribution of the multipath is improved as the number...
In LTE (Long Term Evolution) or LTE-Advanced, MIMO (multiple-input, multiple-output) techniques have the potential to realize high throughput. In order to design and evaluate MIMO system, it is necessary to clarify the space-time path model at mobile station. By clarifying the propagation structure from AoA (angle-of-arrival) estimation it is possible to estimate the performance of MIMO system based...
In this paper, the authors propose a novel design for a slim omnidirectional orthogonal polarization MIMO antenna for the base station. The effect of this antenna decreases the number of antennas needed at the base station compared to the space MIMO antenna. Designing a slim orthogonal polarization MIMO antenna is important issue because the space needed for each polarization antenna must be minimized...
This paper proposes a systematic coexistence scheme for a new radio communication system (secondary system), which is additionally introduced to the service area being operated by an existing communication system (primary system). The same frequency band is allocated for both systems. Our proposal is to protect the primary system from interference, on the basis that the primary and secondary systems...
This paper demonstrates the effectiveness of an adaptive impedance control for mobile terminals with MIMO antennas, which aims to improve the antenna performance in the usage environment, over an FDD-LTE (Frequency Division Duplex — Long Term Evolution) system through experimental measurement by using a developed prototype terminal. Measurement results verify the effectiveness of a proposed control...
In this paper, we discuss the efficient use of a mobile router with multiple radio access technologies (RATs), called a cognitive mobile router (C-MR). In a heterogeneous wireless network, where various infrastructure-based RATs have already been deployed, C-MR selects a high quality RAT from among those available and provides a high quality mobile communication to connecting Wi-Fi user terminals...
Wi-Fi is one of the solutions to overcome the explosion of mobile data traffic and improvement of Wi-Fi performance intensifies the cellular data offload to Wi-Fi. Wi-Fi AP (Access Point) selection at the STA (STAtion) is a key function to improve Wi-Fi throughput. Our proposed method is practical for the AP selection. If an STA can know the throughputs between the STA and surrounding APs before exchanging...
Great East Japan Earthquake caused serious damage such as building collapse, fires and flooding as well as damage of communication infrastructures such as mobile phone networks' base stations, backhaul network cables, and etc. In addition, the amount of mobile communication call reached over several dozen times normal situations, and mobile operators was forced to conduct admission control. These...
A multi-access radio network that efficiently utilizes radio resources is a promising approach to flexible, reliable, high-capacity communication. Regarding cooperative controlling functionality in a heterogeneous radio network, two schemes are considered to be applicable to the efficient usage of multi-radio systems: link selection and link aggregation. This paper focuses on link selection and its...
In this paper, we conducted an experiment using a PC to evaluate the proposed novel selection policy for a communication system in heterogeneous wireless networks. It entailed the use of an analytic hierarchy process (AHP) algorithm that took the mobility of the user terminals into account. In particular, the AHP algorithm demonstrated an excellent improvement in overall performance with existing...
In order to implement the heterogeneous wireless network using multiple wireless systems, it is important to comprehend the transmission quality characteristics such as the transmission throughput and delay, because the network control managements are performed based on these qualities. In this paper, we address the study results regarding the transmission quality characteristics of the Wireless LAN...
Heterogeneous radio network which efficiently utilizes the resources of multi-radio access systems is one of promising approaches for flexible, reliable and high-capacity communication. Regarding the cooperative controlling functionality in the heterogeneous system, two schemes are considered to be applicable to the efficient usage of multi-radio systems. One is a link selection and the other is a...
The heterogeneous radio system is one approach to cognitive radio and a great candidate for creating a new fundamental network that improves the efficiency of frequency resource usage. In this paper, our target is to aggregate the adaptive link of multiple radio systems into a single rich link. Generally, time delays differ among multiple different radio systems, which cause the TCP performance to...
Cognitive radio is a great candidate for creating a new fundamental network architecture improving the efficiency of frequency resource usage. In a heterogeneous network, a cognitive radio system composed with a multi-transmission link is required to select the optimized wireless access network to the terminal. To make the proper selection of a wireless access network to the terminal, the relative...
This paper introduces the latest status of our undergoing project aiming at reliable communications by heterogeneous wireless networks. This project is one of the new Research and Development (R & D) projects in Japan to attain the efficient use of the precious and scarce radio spectrum resources. A test-bed facility has been developed and their features, specifications and some experimental results...
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