Enhanced Circuit-Switched Data (ECSD) is an enhancement of a GSM network in which EDGE is introduced on top of the High-Speed Circuit-Switched Data (HSCSD) service that is used to transfer data in circuit-switched mode on several time slots.

ECSD will enhance the data rates of HSCSD through the introduction of a new modulation scheme (8-PSK) and the introduction of new error correction schemes. The choice of the right error correction scheme can be adapted dynamically if the quality of the radio link changes. This is called link adaptation.

In ECSD there are five different data rates defined. On top of the excisting data rates of 9.6 and 14.4 kbps, there are 3 new data rates introduced. These are given in the table below.

ECSD Modulation and Coding Schemes
Traffic CHannel name Modulation Data rate per time slot (kbps)
TCH/F9.6 GMSK 9.6
TCH/F14.4 GMSK 14.4
E-TCH/F28.8 8-PSK 28.8
E-TCH/F32.0 8-PSK 32.0
E-TCH/F43.2 8-PSK 43.2

If all 8 time slots are used, the maximum data rate will reach 345.6 kbps.

See also