In Enhanced Data rates for GSM Evolution (EDGE) cellular radio networks, a packet-switched transmission mode that supports transmission rates as high as 473.6 kbps. EGPRS estimates link quality in order to adapt the modulation and coding scheme (MCS), of which there are nine levels. Four levels employ Gaussian minimum-shift keying (GMSK) and yield transmission rates up to 140.8 kbps. Five levels employ 8-phase shift keying (8-PSK) and yield transmission rates up to 473.6 kbps. If the system senses that the link quality is good, it will elect to employ the more efficient 8-PSK and, therefore, realize higher signaling rates per time slot and higher data throughput. If the link quality is estimated to be poor, the system will ratchet down to the less capable GMSK. Incremental Redundancy (IR) is an enhanced automatic repeat request (ARQ) technique that forward error correction (FEC) overhead in an attempt to maximize throughput. See also 8-PSK, ARQ, cellular radio, coding, EDGE, FEC, GMSK, GPRS, link, modulation, overhead, packet switch, signaling rate, throughput, and time slot.