An Efficient 3-D Ray Tracing Method: Prediction of Indoor Radio Propagation at 28 GHz in 5G Network

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The antenna used   for mmWave communication plays a critical role. Please explain why horn and   omni antenna are used for the measurement experiments? Usually multi-array   antenna with various beamforming technologies are used for improve the mmWave   communications. It is highly recommended that some other types of antenna or   antenna arrays be used in the experiments.

In our wireless communication centre,   we carried out Continuous Wave (CW) signal measurement by using SISO system. Generally,   in CW measurements horn-omni, horn-horn, and omni-omni antennas are used. The   measurement(horn-omni) data we used in our article is only to validate our   proposed optimum ray tracing method. From this measurement camping, we got   receiver-wise Receiver Signal Strength(RSSI) and pathloss. Due to equipment   limitation, we did not used multi-array antenna. However, our proposed method   simulation can generate power delay profile, but because of CW measurement we   did not present this data in this paper. In simulation calculation, we used   vector sum to get receiver wise accumulated RSSI as measurement from multiple   paths.

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In this paper, the authors proposed a 3D ray tracing   method, which has been validated by comparing with measurement data.  The paper covers a timely and interesting   topic, and it is well-organized. This reviewer has only one request/comment:   it would be better for readers to exploit the results if the authors could   add a discussion section to explain the applicability of the proposed method   and how to relate with statistical channel models widely used in   standardization.

Our proposed method is able to produce the useful channel information such as Receiver Signal   Strength (RSSI), path loss etc. It can provide more accurate scenario wise result in comparison the Empirical Statistical Methods.  Moreover, the main disadvantage of Empirical   Statistical model is lower accuracy as they did not consider specific   scenario wise propagation. Our method belongs in Site Specific models so it helps   to overcome the limitations of Statistical models. This method is faster; as   we optimized the calculation phase, so it overcome the computational so   called limitation of site specific methods also.

Please see the revised manuscript   line 510-515 for more details

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I strongly believe   multi-array antenna will be used for mmWave communications. And it is kind os   strange to use only SISO for the experiment. Even if the experiment is too   limited, at least some simulations should be provided to justify your   proposed solution.

Your suggestions are highly appreciated. However, the focus of this paper on ray tracing method development which belongs to on site-specific models in radio propagation. We have and had to use our existing equipment to verify our results because of   resource limitation. In this circumstance, we think our measurement can serve   the purpose to verify ray tracing result as our focus is not measurement.   Multi-array antenna is used in channel sounding where need additional   equipment such as fast speed multiplexer, etc. Moreover, to process the raw   data need to use- super resolution algorithm such as Multiple Signal   Classification (MUSIC), Estimation of Signal Parameters via Rotational   Invariance Technique (ESPRIT), MATRIX PENCIL etc. to estimate the direction-of-arrival.   It is out of our current project scope.

As per your valued directions we added   proposed optimum method’s some mobile stations simulations PDP in a Table.   Please see the Table 6 and   line   number 497 to 503 for more details.

Many thanks in advance for your   understanding and considerations.

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The title of the   table 6 reads awkward. The English presentation needs great efforts for   improvement. In addition, is there any base line algorithm for comparison in   table 6? 

The table 6 title has been updated. The   manuscript has been copy edited for language usage, spelling, and grammar by   Dr. Tawfig Ahmad A. Eltaif who is the senior lecturer of Faculty of   Engineering Technology at Multimedia University, Melaka Malaysia.

Our proposed method simulation output   is presented in table 6. No base line is algorithm is available for compare table   6 data, as it   generated by our own proposed algorithm. It can be compare with SBRT   algorithm if all parameters including layout are same.