Hello, Thanks for educational video! Could you please explain how FieldFox distinguish two cells(and two PCIs) as they are sharing the same ssb frequency (two signals are on same freq) ? Thanks!
i found this somewhere in the web. "The Physical Cell Identity (PCI) in 5G New Radio (NR) is represented by the Primary and Secondary Synchronization Signals (PSS and SSS) within the Synchronization Signal Block (SSB)1. The PCI is unique to each cell and is used by user equipment (UE) to identify and synchronize with a specific cell1. In the case of multiple cells (each with a unique PCI), each cell would transmit its own SSB. Therefore, two different PCIs would not reside within the same SSB. Instead, each PCI would have its own corresponding SSB1. This is because the positions of the Demodulation Reference Signals (DM-RS) across the PBCH are determined by the PCI1. So, to answer your question, two PCIs cannot reside within the same SSB. Each SSB is associated with a unique PCI, and each cell transmits its own SSB1. This ensures that UEs can correctly identify and synchronize with the appropriate cell." With that, i will think that FieldFox actually scan thru the spectrum. There's a part where user can set the search bandwidth and this is where FieldFox tries to decode the information for all the SSB channel that it found while doing the scan. Hence the long delay for the result to be displayed on the screen. Hope this answers your question.
@@autumngreentech4726 Could you please look at 4:07 once you have populated the results in the scan table? cell0 pci 258 0 86 frequency is 3.606 GHz cell1 pci 803 2 267 frequency is 3.606 GHz Seems like the frequency is the same, correct ?
that's a great observation! 3.606GHz is the carrier signal with about 100MHz of bandwidth and within the same bandwidth there are multiple SSB channels. here is the summary for SSB information and how different channels can be fitted within the 100MHz bandwidth. "In 5G NR (New Radio), the spacing between Synchronization Signal Blocks (SSBs) with different Physical Cell Identifiers (PCIs) depends on several factors, including the carrier frequency and the subcarrier spacing used. The SSB frequency raster and its spacing are defined by the 3GPP standards. Here is an overview: SSB Frequency Raster The SSB frequency raster is the set of frequencies where SSBs can be placed. The placement of SSBs within a given carrier bandwidth follows a defined raster that is determined by the subcarrier spacing (SCS). The SSB raster spacing is as follows: 15 kHz SCS: SSBs are spaced by 240 kHz 30 kHz SCS: SSBs are spaced by 480 kHz 60 kHz SCS: SSBs are spaced by 960 kHz 120 kHz SCS: SSBs are spaced by 1.92 MHz Frequency Range The exact placement of SSBs also depends on the frequency range (FR) in use: FR1 (Sub-6 GHz): SSBs typically use a 30 kHz SCS or 15 kHz SCS, depending on the specific band. FR2 (mmWave): SSBs use a 120 kHz SCS or 240 kHz SCS. Multiple SSBs and PCIs In practice, multiple SSBs can be transmitted within the same carrier, especially in the case of beamforming where different beams cover different spatial directions. Each SSB carries a different PCI. Example Calculation For an SSB with 30 kHz SCS in FR1: SSBs would be spaced 480 kHz apart. If there are multiple SSBs within a carrier, each would be placed at a multiple of 480 kHz from a reference frequency. By adhering to these spacing guidelines, the network can ensure proper decoding and synchronization of SSBs by user equipment (UE), enabling the detection and connection to the correct cell and PCI."
on the Sub Carrier Spacing (SCS): "The bandwidth of a Synchronization Signal Block (SSB) in 5G NR is determined by the subcarrier spacing (SCS) used. The nominal bandwidth for an SSB consists of the Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Physical Broadcast Channel (PBCH). Here's a detailed breakdown: Subcarrier Spacing (SCS) and Bandwidth The 5G NR standard defines different SCS values, and each affects the total bandwidth of an SSB: 1. 15 kHz SCS: SSB occupies 4 Resource Blocks (RBs). Each RB has 12 subcarriers. Total bandwidth: 4 RBs×12 subcarriers×15 kHz=720 kHz. 2. 30 kHz SCS: SSB occupies 4 RBs. Each RB has 12 subcarriers. Total bandwidth: 4 RBs×12 subcarriers×30 kHz=1.44 MHz. 3. 60 kHz SCS: SSB occupies 4 RBs. Each RB has 12 subcarriers. Total bandwidth: 4 RBs×12 subcarriers×60 kHz=2.88 MHz. 4. 120 kHz SCS (used in FR2 or mmWave frequencies): SSB occupies 4 RBs. Each RB has 12 subcarriers. Total bandwidth: 4 RBs×12 subcarriers×120 kHz=5.76 MHz. Summary 15 kHz SCS: 720 kHz 30 kHz SCS: 1.44 MHz 60 kHz SCS: 2.88 MHz 120 kHz SCS: 5.76 MHz These bandwidth values ensure that the synchronization signals and broadcast information within an SSB can be properly transmitted and received by user equipment (UE)."
@@autumngreentech4726 Hi again, thanks for the detailed explanation. What about 4G LTE FDD or TDD? If I'm not wrong, FF can decode several PCI simultaneously, but my confusion is that in 4G SSB is always centralized on carrier frequency (in 5G it could be shifted within total channel BW as you explained) If I'm correct, FF can decode two different PCIs even if PCIs are on the same carrier frequency in 4G?
Thank you! I will be doing this for a client very soon. This was very helpful. You are doing Keysights job! Now if we could get something useful for the indoor mapping.
Did you ever get further with this? I am debating how useful the Indoor Mapping function of the FieldFox is for delivering results to a client. At the moment all I would be able to show are colored dots representing an arbitrary signal level. BTW many thanks for your other FieldFox videos, they have helped me a lot!
the indoor map hasn't changed since this video was recorded. I'm with you on the different color for the dots to represent different signal level. I've talked to someone in Keysight on this and hope there's a new update on this indoor map soon. Glad it helps. Cheers.
it's a high gain low input amplifier I've gotten from eBay. Gain is about 48dB at 1.5GHz and Frequency range is between 1MHz to 2GHz. Input power <-54dBm, input voltage 12V and working currrent about 70mA you can find similar thing here www.ebay.com.au/itm/294642912964?var=593113070149
Hi, nice video. Can you please tell how to add the 'Python with calls to PYVISA' add-on shown at 10:45, when we are trying to export the sequence? In my case I am not getting any add-ons including MATLAB. Do I need to install add-ons separately?
thanks for your support! when you click on "Export Sequence" in Keysight's command Expert, you get the option to either "Copy to Clipboard" or "Save to File". Copy to clipboard will enable you to paste it to your existing code, while save to file will enable you to have these code in one file. You will have to have python installed and also "pyvisa" library prior to executing these code. I'm sure you have done this, but for the sake of others, to install pyvisa after Python is installed, you will have to run CMD in your computer, then type in "python - m pip install pyvisa" without the quotes. hope i answered your question. :)
Thanks for this video it is very helpful. But, I observed that while using differential measurement, the calibration does not give the same accuracy as in single ended. Is there any bug in the AFR software on differential use ? I use the same AFR software as you. Thanks in advance for you help on this topic
@@jalla279 I found this online, not sure whether it'll help you with the differential measurement www.keysight.com/us/en/assets/7018-03037/application-notes/5990-8443.pdf
i lost all the original code. one way to get this sample code is thru the AI code generator. What you can do it try typing in "python code controlling FieldFox using pyvisa"
Very interesting channel, is it possible to know more about the antenna that you're using. I would like to have the datasheet or the web link to TMYTek Active Phase Array Antenna that you used in the measurement. Thanks
This is their website. tmytek.com/ The unit that i used in this demo is BBox GoField. should be able to find the spec in their website. Best is to contact them directly.
For those who are curious on what will happen if we use the internal memory for storage and whether the FieldFox will still working after the memory is full, the short answer is, yes, FieldFox still working even when there's no memory left for recording the new traces. Seems like FieldFox is not using storage as temporary RAM, as what Win7 will do.
Thanks a lot for sharing, I am new in the same field, but I can't good documentation to operate all these RF equipments. Like your voice too, keep it up :)
