RESUMO
In this work, an open Radio Access Network (RAN), compatible, scalable and highly flexible Software Defined Radio (SDR)-based Remote Radio Head (RRH) framework is proposed and designed. Such framework can be used to implement flexible wideband radio solutions, which can be deployed in any region, have common radio management features, and support various channel bandwidths. Moreover, it enables easier access for researchers to nonsimulated cellular networks, reduce system development time, provide test and measurement capabilities, and support existing and emerging wireless communication technologies. The performance of the proposed SDR framework is validated by creating a Network-in-a-Box (NIB) that can operate in multiband multicarrier 4G or 5G standalone (SA) configurations, with an output power of up to 33 dBm. Measurement results show, that the 4G and 5G NIB can achieve, respectively, up to 883 Mbps and 765 Mbps downlink data transfer speeds for a 100 MHz aggregated bandwidth. However, if six carriers are used in the 4G NIB, 1062 Mbps downlink data transfer speed can be achieved. When single user equipment (UE) is used, maximum uplink data transfer speed is 65.8 Mbps and 92.6 Mbps in case of 4G and 5G, respectively. The average packet latency in case of 5G is up to 45.1% lower than 4G. CPU load by the eNodeB and gNodeB is proportional to occupied bandwidth, but under the same aggregated DL bandwidth conditions, gNodeB load on the CPU is lower. Moreover, if only 1 UE is active, under same aggregated bandwidth conditions, the EPC CPU load is up to four times lower than the 5GC.
RESUMO
An increasing demand of magnetic field sensors with high sensitivity at room temperatures and spatial resolution at micro-nanoscales has resulted in numerous investigations of physical phenomena in advanced materials, and fabrication of novel magnetoresistive devices. In this study the novel magnetic field sensor based on combination of a single layer graphene (SLG) and thin nanostructured manganite La0.8Sr0.2MnO3 (LSMO) film-hybrid graphene-manganite (GM) structure, is proposed and fabricated. The hybrid GM structure employs the properties of two materials-SLG and LSMO-on the nanoscale level and results in the enhanced sensitivity to magnetic field of the hybrid sensor on the macroscopic level. Such result is achieved by designing the hybrid GM sensor in a Wheatstone half-bridge which enables to employ in the device operation two effects of nanomaterials-large Lorentz force induced positive magnetoresistance of graphene and colossal negative magnetoresistance of nanostructured manganite film, and significantly increase the sensitivity S of the hybrid GM sensor in comparison with the individual SLG and LSMO sensors: S = 5.5 mV T-1 for SLG, 14.5 mV T-1 for LSMO and 20 mV T-1 for hybrid GM at 0.5 T, when supply voltage was 1.249 V. The hybrid GM sensor operates in the range of (0.1-2.3) T and has lower sensitivity to temperature variations in comparison to the manganite sensor. Moreover, it can be applied for position sensing. The ability to control sensor's characteristics by changing technological conditions of the fabrication of hybrid structure and tuning the nanostructure properties of manganite film is discussed.