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Characterization and Measurement of Wideband Directional Channels in FM Band For New Efficient Wireless Systems

Periodic Reporting for period 1 - FM-4NXTG (Characterization and Measurement of Wideband Directional Channels in FM Band For New Efficient Wireless Systems)

Reporting period: 2016-05-01 to 2018-04-30

The frequency bands are very scarce and they are named one of the most expensive real estates. Hence, it is very critical that the frequency bands are adequately utilised. When the FM radio stations utilisation is analysed it is seen that the FM radio users are tending to move from traditional radio devices to online radio, especially the younger generation from 13 to 35 year-olds. Besides, there is a gradual increase in online radio revenues worldwide with an average annual growth rate of 28 % per year. This trend indicates that the traditional FM radios will phase out in the near future. This also clearly points out a under-utilisation for one of the precious frequency bands. Since the FM Band has excellent area coverage compared to higher frequency bands, it has high potential applications to be used for 5G systems supplementary downlink channels.

This project aims to develop the first directional channel models for the FM Band so that the band can be better utilised for future wireless systems such as 5G. It is now apparent that future wireless systems need some supplementary lower frequency band links on the downlink site in order to meet the required data rates and the FM Band is one of the ideal candidates. However, before the band can be utilised for a digital two-way wireless system, its channel needs to be be better understood. Thus, the main objective of this research is to develop directional channel models for the FM Band and then to validate the developed models through simulations and the field measurements. Once the channel models are available, the performance of the wireless systems can be better assessed before they are deployed.

With the channel models developed for the FM Band, the band can be better utilised for the wireless communication and hence can provide additional wireless connectivity to the society. With the internet-of-things promising all devices to be connected, the utilisation of the FM Band overall will help building a connected society.

The overall objectives of this project with the given framework are: 1) To develop standard directional channel models in FM Band suitable for contemporary wireless systems with multiple antenna and relay networking, 2) For the utilisation of the band for different environments, developing these models for four different environments (typical urban, bad urban, rural area, and hilly terrain), and 3) to validate the developed models via measurements and simulations.

The project outcomes will also provide guidelines for the modelling of channels around the FM Band, enabling the systems operating around this band to be better exploited. For the future work of this project, we will experiment two-way high speed data communication over this frequency band.
As part of this project, we developed simulation environments that utilises the ray-tracing approach. We then started developing stochastic channel models for the FM Band. The models developed supported four different environments, namely typical urban, bad urban, rural area, and hilly terrain. These are the typical environments that FM Band can be utilised in. The models assumed some channel parameters, which then needed to be validated by the field measurements. We then continued on simulations using ray tracing to get the typical channels for the FM Band. The simulation results were used for the validation of the stochastic models. We then performed field measurements for the band. We obtained the permit for the field measurements from Turkish authorities. We picked a site where we can find the four environments mentioned above. The measurements were performed for multi-path channel, direction of arrival, and Doppler measurements. The measurements were performed in Gebze, Turkey, starting in September 2017. From the measurements, we have observed that the stochastic models developed for a given environment indeed represent a FM Band channel. Moreover, based on the measurements we performed, we proposed typical channel power delay profiles for the FM Band. Hence, we can use the developed models in the simulation of the wireless systems. We then extended the results for the relay channels, by simply cascading the channel models.

As part of dissemination, we have published one journal, one conference paper, one patent, and one technical document for Inclusive Radio Communication Networks for 5G and Beyond (IRACON) of EU H2020 Cost program. IRACON contains key European researchers in the area of 5G research. We submitted one more conference paper and will submit one more journal paper that consolidates the overall results of the project.

Apart from the publications, we have performed two meetings with Turkish frequency regulation body and conveyed the potential usage of the FM Band for future systems.
As part of this research, directional channel models for the FM Band have been developed. This is one of the first studies in modelling the FM Band channels for the two-way digital communication systems. The channel delay profiles, direction of arrivals, and other key channel characteristics are obtained for the FM Band channels. This enables wireless communication researchers to better assess the performance of the systems using the FM Band. The approach developed in this study can be used towards other frequency bands’ channel modelling. The project serves to the goal of utilizing lower frequency bands for the future wireless systems and lays out ground work for other frequency bands around the FM Band. These bands are expected to be useful for supplementary downlinks of 5G systems. Hence, there is a direct usage of the results for the future wireless systems.
Channel power delay profile model for a bad urban area.
FM Band channel modelling approach
Overall measurement setup
Channel power delay profile for an urban area relatively far away from the transmitter.
FM-4NXTG logo
One of the routes followed for the measurements.
Channel power delay profile model for a hilly terrain region.
Channel power delay profile for an urban area.
Channel model from stochastic channel modelling approach - Hilly Terrain
Channel power delay profile for a rural area.
Channel power delay profile for a hilly terrain region.