J.2 Dynamic allocation of GSM 400, GSM 800, GSM 900, ER-GSM 900, DCS 1800 and PCS 1900 ARFCNs

3GPP45.005GSM/EDGE Radio transmission and receptionTS

If a PLMN is not using some of frequencies of GSM 400, GSM 800, GSM 900, ER-GSM 900, DCS 1800 or PCS 1900 bands, the corresponding ARFCN numbers may be used for dynamic ARFCN mapping. However, in this case mobiles of previous releases, not supporting dynamic ARFCN mapping but supporting the frequency band concerned, monitor different frequencies than actually intended. In this case the operator must take care that NCC_PERMITTED (See 3GPP TS 44.018) is set in a way that those mobiles ignore unintentional measurements, based on NCC not permitted. Note that in this case a mobile station not supporting dynamic mapping, performs the same number of RXLEV measurements per measurement report per carrier on the BA as the mobile station that supports dynamic mapping. However, some loss of performance may occur when the mobile station is searching synchronisation for carriers on the list of strongest cells.