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Insights on Spectrum Sharing in Heterogeneous Networks with Small Cells

Publication . Silva, Bruno C.; Sousa, Sofia C.; Teixeira, Emanuel; Velez, Fernando

This work explores the viability of 5G New Radio spectrum sharing in Ultra High Frequency (UHF), Super High Frequency (SHF) and millimetre wavebands(mmWaves) in outdoor environments. In the mmWaves the linear cellular topology is considered while in the UHF/SHF bands cells with hexagonal shape are assumed. Performance evaluation includes the study of the behaviour of PHY and supported throughput for 2.6, 3.5, 28, 38, 60 and 73 GHz. While the two-slope model is considered for the 2.6 and 3.5 GHz frequency bands, the modified Friis propagation model, with shadow fading, and different values for the standard deviation, is the considered in the millimeter wavebands. With sharing, lower system capacity is supported. We clearly observe that, for coverage distances up to circa 100 m, the supported throughput is higher at the millimetre wavebands, mainly due to the reduction that characterizes the application of the two-slope propagation model at the UHF/SHF bands.

2018Conference object

Open access

Design of Coordinated HeNB Deployments

Publication . Paulo, Rui; Velez, Fernando; Piro, Giuseppe

Uncoordinated deployment of HeNBs has been widely considered, in the research community. However, due to economic or physical constraints, a coordinated deployment of HeNBs can also be considered. This work studies a selected examples of HeNB deployment. We consider the deployment of four Enterprise HeNB which serve up to 8 simultaneous users, in a building, with a geometry of 5x5 apartments. From the theoretical study on the average SINR, we have learned that the smaller the apartment areas are the higher the values for the average SINR are. The performance evolution of the system focuses on the values obtained for the average goodput, Packet Loss Ratio (PLR) and delay for the Proportional Fair, Frame Level Scheduler (FLS) and Exponential Rule (EXPRule) schedulers, with users using a video and a best effort flows at the same time. For the video flows the maximum average goodput was obtained with the FLS scheduler, but when the PLR is taken into account the EXPRule present a slight advantage. In the case of the BE flows, the EXPRule present the best performance. But the main lesson learned is that it is possible to operate a coordinated HeNB deployments without setting the transmitter power of the HeNBs to the maximum value, which can be a step to achieve a greener system.

2018Conference object

Open access

Performance Evaluation of Source Routing Minimum Cost Forwarding Protocol over 6TiSCH Applied to the OpenMote-B Platform

Publication . Ramos, Anderson; Velez, Fernando; Gardašević, Gordana

The aim of this work is the development of Source Routing Minimum Cost Forwarding (SRMCF) protocol over IPv6 over the TSCH mode of IEEE 802.15.4e (6TiSCH), evaluating the performance of these protocols for the Internet of Things (IoT). To perform this evaluation, this work is making use of the OpenWSN project platform, which implements IEEE 802.15.4e in an open source environment. The evaluation process is also being done in the most recent version of the OpenMote-B platform. Another goal of this collaboration is to give contribution to the investigation of the applicability of quality of service (QoS) applied to the IEEE 802.15.4e standard. In the present stage of development, the efforts are concentrated on the programming of the required code, and the adaptation of the OpenWSN stack. Once the programming code is implemented, the team will investigate the possibilities to apply quality of service over the stack developed. Next, the team will also investigate the possibilities to explore long range routing techniques using the OpenMote platforms. In this task, we will use xBee, LoraWAN, Raspberry PI and Arduino platforms.

2018Conference object

Open access

An Extensive Study on the Performance Evaluation and Scheduling of HeNBs

Publication . Paulo, Rui R.; Velez, Fernando J.

Since the dawn of mobile communication systems, reducing the cell size has been one option to increase the signal-to-interference-plus-noise ratio (SINR) in both links. The impact of this reduction can be perfectly understood by considering Shannon’s law. This work studies in detail the performance of Home eNBs (HeNBs), nodes with a smaller coverage area. After a detailed theoretical study of the SINR, a simulation approach is used to extract performance results in small cell indoor scenarios. Results corresponding to the goodput, delay and packet loss ratio are analyzed. Based on an improved version of LTE-Sim, the proportional fair, frame level scheduler (FLS) and exponential rule are tested in an indoor environment. With the saturation conditions taken into consideration, the FLS performs better than the other schedulers. This work shows that with the considered applications, it is possible to achieve a reduction in the transmitter power of HeNBs without compromising the small cell network performance.

2021-03-08Journal article

Open access

Radio Resource Management of Heterogeneous Small Cell Networks

Publication . Paulo, Rui Filipe Rosa; Velez, Fernando José da Silva

While mobile communication users demand new high speed services with enhanced quality, there will always be a need to optimize cellular networks. This work explores the behavior of indoor and outdoor small cells while reducing the cell size to increase system capacity in both links. After justifying evolution of the use of small cells, the concepts of ultra-dense networks and heterogeneous networks toward 5G are then presented. In the initial part of this work, we have chosen a 3GPP 5x5 grid geometry for indoor scenarios. The average signal-to-interference-plus-noise ratio (SINR) has been studied for reuse pattern two and two types of deployment topologies, one with 25 HeNBs and another with 4 HeNBs. We have also addressed the exponential effective SINR mapping (EESM) by extending the study for topologies with 5 and 6 HeNBs. Based on an improved version of LTE-Sim, network performance has been evaluated in terms of the goodput, packet loss ratio (PLR), delay, and the maximum number of supported users. We have evaluated the performance by considering 4, 5, 6 and 25 HeNBs. Results complied with the 3GPP recommendations for PLR and delay. One observed that system capacity is higher for topologies with 25 HeNBs, followed by topologies with 6 HeNBs and 4 HeNBS, and then the indoor deployments with 5 HeNBs. Different packet schedulers have been considered. Results have shown that, with the considered applications and schedulers, it is possible to reduce the transmitter power of HeNBs without compromising the small cell network performance. In the final part of the work an urban micro line-of-sight cell scenario has been studied by comparing the 2.6 GHz, 3.5 GHz, and 5.62 GHz frequency bands while considering the ITU-R M.2135-1 dual slope path loss model (DS-PLM) in the system level simulations. Results have been obtained for different values of the cell radius. System capacity has been determined by considering the 3GPP quality target of 2% for video applications. For all schedulers and frequency bands, for cell radius shorter than the breakpoint distance, the PLR increases when the cell radius decreases. [...]

2022-10-26Doctoral thesis

Open access