Dual-Sideband Constant-Envelope Frequency-Hopping Binary Offset Carrier Multiplexing Modulation for Satellite Navigation
Round 1
Reviewer 1 Report
The authors propose a novel multicarrier constant-envelope multiplexing modulation named asymmetric constant-envelope frequency-hopping binary offset carrier multiplexing (ACE- FHBOC). The proposed dual-sideband constant-envelope multiplexing modulation is aimed to provide higher design flexibility in the number of subcarrier frequencies. The authors present mathematical models and propose typical applications of ACE-FHBOC. Following that they discuss several generation schemes and derive the ACF and power spectrum density function. In order to simulate and analyze the proposed modulation scheme the authors develop a software-defined receiver. The presented results show that the proposed method exhibits lower ACF ambiguity, better anti-narrowband interference, and multipath performance than conventional methods.
The manuscript is mostly well written and contains some interesting research results.
The simulation scheme is presented in figure 11, and some simulation parameters inTable 4. However, there are some processing blocks in the Figure 11 which are not descbribed into sufficient details within the text. It would be useful for the reader to understand the main characteristics of these parts of the system including the Interference, Noise, Filtering, Bit Synchronization, and others.
Author Response
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Author Response.doc
Reviewer 2 Report
Dear authors,
Using multiple carriers with asymmetric constant envelope to achieve carrier modulation with frequency hopping and binary offset is an interesting approach to deal with narrowband interference, carrier binary offset ambiguity, and finally multipath, which is a "blister" in urban positioning, as you have already published in GPS solutions. The multiplexing algorithm is theoretically well justified, and the behaviour of the observables and results in time and phase space is adequately illustrated and explained. Impressive improvement in multiplexing efficiency and lower expectation of false locking at lower C/N_0, significantly lower NELP multipath errors compared to ACE-BOC for the signals used as examples. It would be appropriate to at least describe the characteristics of the "example signals" and their time lengths, not just how the results based on them were obtained.
I do not doubt the quality of results, nor the quality and reliability of the simulator used. I recommend to ler the readers to which SDR receiver (generic?) was used (in Section 5.2), as I believe the results presented provide a solid basis for further proof-of-concept lab testing and deployment in real-world conditions.
Best regards.
Author Response
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Reviewer 3 Report
My comments for Authors:
1. abstract is too long, please correct it. Maybe you could add obtained results in abstract.
2. all acronyms must be explained in text, please check it.
3. I don't see chapter with discussion, please compare your solution with references, why your solution is better? What is a major contribution of this solution?
4. conclusion, this paragraph should be improved.
5. References, please add more positions.
Author Response
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Author Response File: Author Response.doc
