tag:blogger.com,1999:blog-1834236085756782640.post3265358370132226322..comments2024-03-21T14:19:53.378+00:00Comments on The 3G4G Blog: Air-Ground-Air communications in Mission Critical scenariosZahid Ghadialyhttp://www.blogger.com/profile/11618208626682295272noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-1834236085756782640.post-46866836069672169822015-11-13T21:51:19.675+00:002015-11-13T21:51:19.675+00:00Anonymous comment looks logical.Anonymous comment looks logical.Mirzahttps://www.blogger.com/profile/16397741927060924911noreply@blogger.comtag:blogger.com,1999:blog-1834236085756782640.post-66861181827091707232015-08-03T00:05:49.519+01:002015-08-03T00:05:49.519+01:00LTEA can support Doppler shift up to 600Hz (PRACH)...LTEA can support Doppler shift up to 600Hz (PRACH) ref 3GPP.<br /><br />If an aircraft is flying towards a cell, level flight, 1000kph, at a height of 10,000m and is at a ground distance of say 10km from the cell, what is the closing speed to the cell?<br /><br />it is 1000*cos(45deg) = 707kph, agree? <br /><br />in that case it could not communicate with the cell due to the high Doppler shift.<br /><br />to get a closing speed less than 500kph, angle is >60deg.<br /><br />the number of cells required will be huge if that is the only way of addressing the Doppler shift problem.<br /><br />do the trigonometry, speed is a problem. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1834236085756782640.post-77436632447517833702015-03-18T04:45:11.581+00:002015-03-18T04:45:11.581+00:00Hi,
In US, DA2G commercial service is already ava...Hi, <br />In US, DA2G commercial service is already available. Only one company provides it. New company is planning same service with LTE. The aim of CEPT study is to provide same service in Europe. <br />The objective of 3GPP study is just answer for French administration. <br />NGMN 5G white paper proposes to include DA2G service into the 5G vision. I think it is more interesting topic for DA2G.Anonymoushttps://www.blogger.com/profile/12927934211081354416noreply@blogger.comtag:blogger.com,1999:blog-1834236085756782640.post-53545046540915372442015-03-17T21:27:39.464+00:002015-03-17T21:27:39.464+00:00Zahid,
At the altitude where planes fly the main ...Zahid, <br />At the altitude where planes fly the main problem will be interferences since at 10km hight you are in line of sight with every LTE relay landing 300km around (unless specific spectrum bands are allocated to this application). <br /><br />On your drawing if you replace the plane by something flying lower, like an helicopter, this will be will be more realistic, and this may be a particularly useful case for example to do the coverage of a disaster place during a civil security mission.Louis GIBAULT (via 3GPP LTE/LTE-A Standards Linkedin group)noreply@blogger.comtag:blogger.com,1999:blog-1834236085756782640.post-83777249551935449762015-03-17T07:03:48.738+00:002015-03-17T07:03:48.738+00:00"Except of cell size [sic], and parameter ada..."Except of cell size [sic], and parameter adaptation for synchronization/handover processes in eNBs no difference of DA2GC ground network to usual terrestrial LTE networks" <br />"Altitude of about 10 km (first flight phase)." <br /><br />Very interesting! I guess at that altitude, the relative speeds of the communicating entities is not actually that high, so might actually be a less extreme use case to that of a high speed train.Oliver Thomas (via 3GPP LTE/LTE-A Standards Linkedin group)noreply@blogger.com