or to the fixed-measurement antenna. Page the test unit, direct it to the traffic channel of interest, and put it in loopback mode to enable BER measurement. Place the test unit in the chamber. In the case of simulated-use testing, place the unit in the intended position relative to the tissue-simulating object (e.g., head or hand phantom). Set the base station simulator to a specific output power and perform a BER measurement. Increase or decrease the base station output power as needed and repeat step 5 until the lowest output power is found that gives a BER better than the specified target BER. Repeat steps 5 and 6 for each position of the mode stirrers. Calculate the TIS value as described next. 2009 by Taylor & Francis Group, LLC Measuring Performance of 3GPP LTE Terminals The TIS parameter is calculated by the following equation: TIS = (12.23) where PBSS(n) is the output power from the base station simulator when this is adjusted to give the specified BER in the test unit for position n of the mode stirrers; N is the total number of stirrer positions; Tcable is the transmission in the cable connecting the base station simulator to the fixed-measurement antenna; and Gref and Rfix are as defined in the calibration section. The advantage of the TIS parameter is that it is well defined and commonly used, and the relation to the radiation efficiency of the test unit's antenna is intuitive. However, TIS measurements are inherently time consuming due to the large number of BER measurements that have to be done during the measure- ment sequence. The fact that TIS is a static measurement and does not include any fading performance can also be considered a disadvantage because the actual TIS performance is not reflected in a real-use performance. This means that units that are optimized for TIS may not be the units that perform best in a real scenario. 12.3.4 Measurement of Average Fading Sensitivity Average fading sensitivity is defined as the lowest average available power during a fading sequence for which the tes