8.1 Conclusion
This master thesis investigated the performance of LTE network utilized in a smart grid. The study has proven that LTE network is a promising solution due to its low latency and large bandwidth.
Firstly, the communication requirements in a smart objects are categorized into three parts: a) communication in substations/distributed generation (DG); b) col-lecting and dissemination of phasor data; and c) colcol-lecting and dissemination of consumption data. In each part, we specified the communication requirements in term of latency and bandwidth mainly based on IEEE standards and related re-search. The latency less than 10 ms and the peak rate larger than 22 Mbps are required for a proposed hypothetical smart microgrid in this thesis. Secondly, we estimated the single antenna LTE performance both theoretically and experimen-tally. The theoretical analysis indicates that the latency is less than 9.5 ms, the peak rate is more than 100 Mbps in downlink and 67 Mbps in uplink. The experimental measurements show that the latency and peak rates of the LTE network provided by TELE2 fulfil the requirements for the communication in the hypothetical smart microgrid as summarized in Table 8.1, while the latency of the LTE network pro-vided by TELIA is a little longer than the required. The latency can be improved using an appropriate scheduler.
Last, a scheduler was designed to optimize the latency. The simulation results show the latency is reduced to around 5 ms for smart objects communication via LTE. In addition, the results show that LTE can handle more than 300 PMUs in a single cell.
It must be noted that we assume all the physical resources are allocated to data transmission without considering any resources needed for control signalling in this thesis.
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CHAPTER 8. CONCLUSION & FUTURE WORK 43
Table 8.1. Comparison between communication requirements and experiment re-sults.
Type Requirements Experiment Comments
TELE2 TELIA TELE2 TELIA
Latency 10 ms 9.2725 ms 13.2375 ms 83.27% ≈ 0 Peak rate 22 Mbps ≥ 30 Mbps ≥ 30
Here latency results from experiment is obtained by halving mean RTT value of 100 bytes from Chapter 6. Based on the “best” fitting model, the probability that the latency of each LTE network will be less than 10 ms is evaluated and filled in Comments column.
8.2 Future Work
Although it has been proven that 3GPP LTE is a promising solution to interconnect devices in a smart grid, this smart microgrid only includes the components PMU and AMI. In practice, there are many other potential components which need two-way communicational infrastructures to help a power grid achieve the goals of a smart grid. For instance, the transformers, breakers and other devices mounted on electricity buses need to report their status and receive remote control commands.
More investigation needs to be done before PMU and AMI are deployed in a real smart grid. In addition, the real time electricity price is still under development.
Furthermore, we only studied the performance of one single antenna LTE net-work in this thesis. The performance of MIMO LTE needs to be analysed not only for fulfilling the communication requirements but also for the scheduler de-sign. Therefore a more complete simulation model for LTE is required. Based on the model, a scheduler which can allocate physical resources in both time and frequency domains can be designed.
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