1. Method for dynamically optimize data throughput at the radio interfaces of a packet data cellular network having at disposal of said interfaces one or more type of modulations having different immunity from transmission errors when used for transmitting bursts of data, packed-up in blocks, between mobile stations (MS) and the serving base station (BTS), and vice versa, obtaining for each available modulation an upgrade and/or a downgrade tabulated threshold of the Block Error Rate, or BLER, delimiting a range in which that modulation outperforms the other available modulations in term of net data throughput; the BLER on the relevant temporary connection being continuously averaged and compared with the tabulated thresholds for selecting the proper modulation characterized in that includes the steps of: combining each available modulation with two or more coding schemes obtaining as many modulation-and-coding schemes, termed hereinafter MCSs, with different protection against transmission errors; obtaining for each MCS a first upgrade and/or a first downgrade tabulated BLER threshold (A) valid for low-diversity RF channels, delimiting a range in which that MCS outperforms the other available MCSs in term of net data throughput, considering as low-diversity a channel without frequency hopping and with low user mobility; obtaining for each MCS a second upgrade and/or a second downgrade tabulated BLER threshold (B) valid for high-diversity RF channels, delimiting a range in which that MCS outperforms the other available MCSs in term of net data throughput, considering as high-diversity a channel characterized by frequency hopping or high user mobility; selecting either the first (A) or the second (B) tabulated thresholds according to the diversity of the RF channel which sustains the temporary connection and use the selected thresholds for discriminating the right MCS.