LTE cell radius

LTE_tutorial_FemtoForum_part1

LTE - The UMTS Long TermEvolution From Theory to Practice- Stefania Sesia, Issam Toufik,Matthew Baker - Google Bøker.url

Preamble format.URL

The range limit is primarily determined by the configured PRACH format, whichdetermines the effective window size for a RACH preamble. Format 0 has thesmallest window, corresponding to about 14 km, while Format 3 allows ranges upto about 103 km.The propagation delay between the eNB and the UE is not likely to be the mainfactor in any delay-sensitive applications; at 100 km, the signal takes less than amillisecond to get to the UE. The path loss, however, will be a significant factor atthat distance.Note that once the UE has established its RRC connection, it can move fartheraway and still maintain communications, as long as both ends of the link can heareach other.

I think of it as two separate issues:what is the maximum range that a UEcan access the eNB (which is limitedby the propagation delay that thePRACH is configured to handle), andwhat is the maximum range at whichthe UE can maintain its connection(which depends on the link budget).

Doc6-LTE%20Workshop_TUN_Session5_Performance%20Evaluation

8. 18.2.2.1 Initial Timing Advance • After a UE has rst synchronized its receiver to the downlink transmissions received from the eNodeB(see Section 7.2), the initial timing advance is set by means of the random access procedure described in Section 17.3. This involves theUE transmitting a random access preamble from which the eNodeB estimates the uplink timing and responds with an 11-bit initial timingadvance command contained within the Random Access Response (RAR) message. This allows the timing advance to be con gured by theeNodeB with a granularity of 0.52 µs from 0 up to a maximum of 0.67 ms,1 corresponding to a cell radius of 100km. 8

3GPP Long Term Evolution (LTE)

LTE cell radius (2).mmap - 10/30/2014 -