Dear Friends,

I am trying to understand the difference between Type 1 and Type 2 Timing Advance in LTEⁱ.

Please can one of the LTE Gurus illuminate?

Here is an excerpt from 36.305

8.3.1 General
In the Cell ID (CIDⁱ)-based method, the UEⁱ position is estimated with the knowledge of the geographical coordinates of its serving eNodeBⁱ. Enhanced Cell ID (E-CID) positioning refers to techniques which use additional UE and/or E UTRANⁱ radio resource related measurements to improve the UE location estimate. For E-UTRAN access, these measurements may include [20, 21]:
UE measurements ([20], [21]):
- Reference signal received power (RSRP);
- Reference Signal Received Quality (RSRQ);
- UE Rx – Tx time difference.
E-UTRAN measurements ([20], [21]):
- eNB Rx – Tx time difference
- Timing Advance (TADV):
- Type1: TADV = (eNB Rx – Tx time difference) + (UE Rx – Tx time difference)
- Type2: TADV = eNB Rx – Tx time difference;

Thanks.

Cheers,

Kal