estimate distance

[Max]

Regarding TA: it's very approximate measure of distance:

1) it's not yet implemented the way it should - see
https://projects.osmocom.org/issues/1545 for example

2) Increase in TA +1 approximately equals to increase of +550 meters
distance between phone and BS (1 bit period = 3.69 usec times speed of
light)

3) There's guard period (8.25 for normal bursts) between transmissions
which allows it not to overlap with next one so even the phone with
incorrect TA might still work with BTS to some extend.


On 11/02/2016 08:07 PM, Keith Whyte wrote:
> On 02/11/16 13:01, sami wrote:
>
>> Hi,
>>
>> Is there a function in OpenBSC that can help in estimating the diastase of the connected phone ? For example, something that gives the value of the power received by the phone from the BTS and the power received by the BTS from the phone (during paging or active call).
>>
>> best regards,
> Hi sami. You can see those uplink and downlink power levels with 'show
> lchan' in OpenBSC.
> For example:
>
>   Measurement Report:
>     Flags: 
>     L1 MS Power: 33 dBm, Timing Advance: 9
>     RXL-FULL-dl:  -86 dBm, RXL-SUB-dl:  -87 dBm RXQ-FULL-dl: 0,
> RXQ-SUB-dl: 0
>     RXL-FULL-ul:  -87 dBm, RXL-SUB-ul:  -47 dBm RXQ-FULL-ul: 0,
> RXQ-SUB-ul: 0
>
> There you will also see "Timing Advance" although I'm not sure how
> exactly to interpret that. Maybe somebody else might comment. I'm also
> not sure what RXQ is, although I've seen those numbers increase when I
> use very low power levels in osmotrx and move the MS away from the USRP,
> so I presume it's an indicator of RF errors?
> I'll take the opportunity to also ask for clarification on that :)
>
>
>

-- 
Max Suraev <msuraev at sysmocom.de> http://www.sysmocom.de/
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