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- Performance Evaluation and Packet Scheduling in HeNB DeploymentsPublication . Paulo, Rui R.; Velez, Fernando; Piro, GiuseppeThe unsupervised and chaotic deployment of Home eNBs (HeNBs) is leading to high levels of interference. To understand the behaviour of the interference of these uncoordinated deployments is vital to reach significant capacity improvement and also to explore opportunities to save energy. This paper considers high and middle interference level scenarios, with a maximum of four users per cell. HeNBs indoor deployed is considered within building. We theoretically analyse the traffic performance of this scenario through the study of the Signal-to-Interference-plus-Noise-Ratio (SINR). Through the use of the LTE-Sim simulator one obtains the quality indicators for two flows that are being utilised by the users. Video and best effort are studied, while varying the transmitter power and the areas of the apartments. The achieved SINR is higher (around 10 dBm) when the area of the cells is smaller. The variation of the transmitter power of the HeNBs does not present any significant impact. Noticeable throughout the simulations is observed that is possible to operate the system without setting the transmitter power of HeNBs to the maximum value at both interference levels. Simulation results also show that with the considered flows is possible to serve the maximum number of four users per HeNB with high quality. This statement is confirmed by the maximum achieved Packet Loss Ratio for video with a value of value of 1.6 %, which is lower than the maximum of 2 % indicated by the 3GPP. Taking into account the obtained results it is possible to promote a reduction in energy consumption of the HeNBs without penalizing the service quality.
- Design of Coordinated HeNB DeploymentsPublication . Paulo, Rui; Velez, Fernando; Piro, GiuseppeUncoordinated 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.
- Extending the LTE-Sim Simulator with Multi-Band Scheduling Algorithms for Carrier Aggregation in LTE-Advanced ScenariosPublication . Robalo, Daniel; Velez, Fernando J.; Paulo, Rui R.; Piro, GiuseppeCarrier Aggregation (CA) has been proposed by 3GPP LTE-Advanced to meet or even exceed IMT-Advanced systems enhanced peak data rates requirements. In its rationale, multiple Component Carriers (CC) can be flexibly aggregated so that user equipment can access a total bandwidth of up to 100 MHz. As each CC has the same structure as the one from LTE R8, CA does not require notable changes in the LTE physical layer structure. Nevertheless, the way radio resources are allocated to mobile users in CA scenarios is still an hot research topic and the availability of an open source tool modelling such kind of feature is highly demanded in both academia and industry contexts. The present contribution is three-folded. First, it presents an open source and freeware extension of the well-known LTE-Sim simulator, which implements CA functionalities. Second, it also proposes an implementation of multi-band scheduling strategies able to optimally distribute radio resource among mobile users in the presence of multiple CCs and strict Quality of Service (QoS) constraints. Third, computer simulations have been also carried out to demonstrate the effectiveness of the aforementioned contributions. In particular, simulation results show the capacity improvements achieved by the proposed Enhanced Multi Scheduler against systems without CA, considering values of the bandwidth per component carrier of 5 and 20 MHz, in terms of average cell packet loss, delay, goodput and spectral efficiency.