To perform link adaptation at radio interfaces of an enhanced packet data
cellular network the system behavior is simulated for different C/I
conditions. Two sets of tables are obtained, each table including upgrade
and downgrade thresholds expressed in terms of Block Error Rate (BLER).
The tables are specialized for taking into account EGPRS type II hybrid
ARQ, Incremental Redundancy (IR). Transmitted blocks are checked for FEC
and results are sent to the network that continuously updates BLER. A
reliability filter output is used to decide the weight between new and
old measurements. IR efficiency is tested for each incoming block and an
indicative variable IR_status is filtered. Each threshold of BLER to be
used is obtained by linear interpolation between the tabulated threshold
without IR and with perfect IR, both weighed with filtered IR_status.
Filtered BLER is compared with interpolated thresholds for testing the
incoming of a MCS switching condition.