What is a Handover Hysteresis Margin in Cellular Communications?

Explains how cellular networks decide when to hand over a mobile user from one base station to another.
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[@CuongPhamQ]

Dear Prof. What is the name of software that you use to create lecture in video?

[@georgepalafox5967]

Excellent explanation Sir! Thanks.

[@iain_explains]

Thanks. I'm glad you liked it.

[@pitmaler4439]

Hello I have a more general question concerning the sample rate. We must satisfy the sampling theorem. I thought when we now transmit in the mmWave region, the sampling frequency can never be in such high GHz regions. First one convert it down to the base band and sample next. So the sampling frequency is much lower. Is that conclusion right? Or are there systems that sample in the band pass region? Thanks a lot.

[@iain_explains]

Well yes, sort of. But you only need to sample at twice the highest frequency if you plan to fully reconstruct the analog waveform at some later time. If you're only interested in the digital information that the analog waveform is representing, then you can sample at lower rates. This video might help: "How to Avoid ISI in Digital Communications: Nyquist Zero ISI Theorem" kzbin.info/www/bejne/qZjchZ9_bqemgcU

[@pitmaler4439]

Thanks, I knwo that electric and magnetic field behave E,H ~ 1/r and S=ExH (I believe that is the power density) behaves 1/r^2........and this S is the transmission power you mentioned, is that right?

[@iain_explains]

Yes, that's right. More details at: "What are Antenna Gain, EIRP, and Friis Equation?" kzbin.info/www/bejne/o3nSY2CcartrjJY

[@priyadarshimukherjee9571]

Thank you for the simple explanation Professor... but I have a simple query (may sound obvious and silly to you). Is the hysteresis margin somehow related to the problem of optimal threshold selection for minimizing the error in detection probability OR is it completely based on the long term fading component and the aspect of short term fading gets completely ignored here?

[@iain_explains]

Don't worry, obvious questions are sometimes the best ones! Your question is an interesting one. It does look a bit like the detection error threshold, but these curves are not p.d.f.s - they are simply the power drop as a function of distance for free-space propagation. There is nothing random here. The hysteresis in the choice of threshold is used to allow for fading (both short term and long term).

[@priyadarshimukherjee9571]

Thank you Professor.

[@jonesy3516]

Dear Professor, Thank you again for your great explanations. :) I have another question, but I may have misunderstood the main message: Could you please explain why it is sufficient to sample complex signals with f_sampling = f_max and not f_sampling >= 2 * f_max as it is required for purely real signals? As far as I know, the mobile communication standards stipulate that a 10 MHz signal is sampled with 15.36MSamp/s instead of 20MHz. Thank you very much!

[@iain_explains]

I think you're getting confused between the Sampling Theorem (which applies when you want to sample an analog signal in such a way that you could exactly reproduce it from the samples), and the Zero-ISI Data Transmission Theorem (which applies when you want to send digital data without the waveforms overlapping in time. For more on this, see: "How to Avoid ISI in Digital Communications: Nyquist Zero ISI Theorem" kzbin.info/www/bejne/qZjchZ9_bqemgcU

[@manutauer]

Hello, perhaps could be one of the futur topics be the use of the Fisher Information together with the Cramer Rao Bound. (I know you have a separate video on the FI). Lastly I read a few times about these mathematical tools in terms of positioning and ranging via mobile comm.. Thanks.

[@iain_explains]

Thanks for the suggestion. I've put it on my "to do" list.

[@ahmednor5806]

🙏💐