the region (defined by sNonIntraSearch,PIQ) shown in Figure 15.2, or in other words, when the UE is considered to be in unacceptable radio conditions. In addition to periodic search within the current cell, the cell search is also restarted after successful reselection and reading of the system information in the new cell after reselection. Also in the case that the serving cell does not fulfil the cell camping criteria, discussed in the beginning of this chapter, the UE will start neighbour cell search and measurement procedure for all layers broadcast on BCCH, regardless of their priorities and the values of sIntraSearch and sNonIntraSearch. If either serving cell RSRP or RSRQ (optional) is below the corresponding sNonIntraSearch level and quality threshold then the UE is considered to be in bad RF conditions and has to search for higher priority cells more often. The search interval in this case is not specified exactly in [2]. Instead the so-called maximum allowed 'detection time' is given. The detection time is the maximum time allowed to identify, measure and evaluate the cell reselection criteria for a candidate. 3 A summary of detection times is given in Table 15.5 for one layer. The table applies to lower priority cells and higher priority cells when UE is considered to be in bad radio conditions. A nominal value for the search interval can be deduced as the difference between detection time and the evaluation time, although it should be remembered that UE does not strictly speaking have to comply with such nominal value as long as the overall detection time requirement is satisfied. When intra-frequency or inter-frequency LTE cell search is active, searching one layer for new cells must not take longer than 20 DRX cycles, which is obtained as the difference between values in Tables 15.4 and 15.5. The serving frequency is searched (at least) once every 20 DRX cycles constantly regardless of the number of other layers. For inter-frequency LTE layers one layer must be searched once every 20 DRX cycles, and