In GSM, the maximum distance between cell-site coverage outside of linkbudget depends on Timing Advance for example with regular GSM without extended range the limit is 35km.
I know LTE utilizes Timing Advance- so does that mean that there is hard range limit due to system limitation and not linkbudget for LTE?
For example, if I have a eNodeB about 85 miles away and Ue terminal connected to directional panel antennas with sufficient signal strength and balanced linkbudget, can I still do video or voip or other applications that are time sensitive? Or will latency be limiting factor? Or is there a hard limitation like GSM?
it would be great if you can refer to some 3GPP standard that discusses this?
Thanks.
RF technician
Jonah Obrian
The range limit is primarily determined by the configured PRACH format, which determines the effective window size for a RACH preamble. Format 0 has the smallest window, corresponding to about 14 km, while Format 3 allows ranges up to about 103 km.
The propagation delay between the eNB and the UE is not likely to be the main factor in any delay-sensitive applications; at 100 km, the signal takes less than a millisecond to get to the UE. The path loss, however, will be a significant factor at that distance.
Note that once the UE has established its RRC connection, it can move farther away and still maintain communications, as long as both ends of the link can hear each other.
Thanks Don,
I appreciate the answer Don. So, maximum cell range in terms of access or setting up on network is 100Km(63.3miles). However, once the Ue dedicated mode(RRC connect) it can move or be more more than 63.3 miles away as long it has sufficient signal strength reach the eNodeB. But for all practical purpose it Access range(63.3miles) is real limit because if the Ue setup about 63.3 miles away and drives further let's about 65 miles away and drops for whatever it can't setup or access the network (65miles away)? This is similar to GSM but in GSM the mobile in dedicated mode(voice call) will drop when it reaches 35km limit if it doesn't have extended range.
I think of it as two separate issues: what is the maximum range that a UE can access the eNB (which is limited by the propagation delay that the PRACH is configured to handle), and what is the maximum range at which the UE can maintain its connection (which depends on the link budget).